Giao an Mon Hoc Thiet Bi Thuc Pham

7/27/2019 Giao an Mon Hoc Thiet Bi Thuc Pham

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I HC NNG

TRNG I HC BCH KHOA

KHOA HA- B MN CNG NGH THC PHM

GIO N MN HC

THIT B THC PHM

( 4 N V HC TRNH)

BIN SON: TS. TRNG TH MINH HNH


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TI LIU THAM KHO

1. Lm Ch, Nguyn Nh Thung, on D, H L Vin (dch), Nhng qutrnh v thit b sn xut thc phm, Nh xut bn khoa hc k thut, HNi, 1989.

2. on D (ch bin), Bi c Hi, Mai vn L, Nguyn Nh Thung, Cngngh v cc my ch bin lng thc, Nh xut bn khoa hc k thut, H

Ni, 1983.

3. GS Trn Thanh K, My lnh, Trng i hc Bch khoa Thnh ph HCh Minh, 1992.

4. Bi Hi, Dng Quc Hng, H Mnh Th, Cc thit b trao i nhit,Trng i hc Bch khoa H N, 1996.

5. PGS.TS L vn Hong, Cc qu trnh v thit b cng ngh sinh hc trongcng nghip, Nh xut bn khoa hc k thut, H Ni, 2004.

6. V B Minh, Hong Minh Nam, C hc vt liu ri, Nh xut bn khoahc v k thut ,1998.

7. Nguyn Nh Nam, Trn Th Thanh,My gia cng c hc nng sn - thcphm, Nh xut bn gio dc, 2000.

8. Nguyn Trng Th ( dch), C s thit k my thc phm, A.I.A- Xokolov,Nh xut bn khoa hc k thut, H Ni, 1976.

9. Cc qu trnh c bn trong sn xut thc phm , Nh xut bn gio dc,2000.


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NI DUNG CHNG TRNH

M U

PHN 1: Cc my vn chuyn

Chng 1: Cc my v thit b vn chuynPHN 2: Cc my c hc

Chng 2: Cc my phn loi v lm sch

Chng 3: Cc my lm nh

Chng 4: Cc my p

Chng 5: Cc my nh lng

Chng 6: Cc my ra chai

PHN 3: Cc thit b nhitChng 7: Cc thit b nhit


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1

M U

1. Cu to v phn loi my sn xut thc phm

1.1. Cu to my

My hin i ch yu gm:

-Thit b np liu

-Cc c cu tha hnh c b phn lm vic

-Cc c cu truyn dn (ng c) [ngun ng lc]

-Cc my hin i thng c thm hng lot cc b phn ph :

+ iu chnh v hiu chnh s lm vic ca my

+ iu chnh my, khi ng, dng my, kim tra

+ Bo v v chuyn i

1.2. Phn loi my sn xut thc phm

1.2.1. Theo tnh cht tc dng ln sn phm gia cng:

- My: l trang b trong sn phm chu tc ng c hc, khi gia cng trn my y, sn

phm khng thay i tnh cht ca n, m ch thay i hnh dng, kch thc hoc cc

thng s tng t khc chu tc ng c hc

- Thit b: l trang b nh my cng tc c bit, trong sn phm b thay i tnh cht

vt l hay ha hc hoc trng thi t hp di cc tc dng nh: c l, sinh ha, nhit in

c im: + My: c cc b phn lm vic chuyn ng trc tip tc dng c hc ln sn

phm gia cng

+ Thit b: C mt khong khng gian nht nh (bung lm vic) trong

tin hnh tc dng ln sn phm vi mc ch thay i tnh cht ca n

1.2.2. Theo cu to ca qu trnh

- My lm vic gin on: Sn phm gia cng chu tc dng trong sut thi gian ca mt

chu k nht nh. Sau qu trnh li tip din lp li c tnh cht chu k. Thnh phmc ly ra cui chu k

- My lm vic lin tc: Thi gian ca qu trnh lm vic n nh, np sn phm ban u

v ly sn phm c tin hnh ng thi. Cc b phn lm vic trong nhng iu kin

n nh

1.2.3. Theo mc c kh ha v t ng ha


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2

- My khng t ng

- My bn t ng

- My t ng

1.2.4. Theo nguyn tc phi hp trong dy chuyn sn xut

- My ring l- Nhng my t hp hoc b my

- Nhng my lin hp

- H thng my t ng

1.2.5. Theo c im chc nng

- Cc my v thit b vn chuyn: Bng ti, gu ti, vt ti

- Cc thit b c hc: My phn loi, my nghin, my xay xt, my ct thi, my ch,

my p,...- Cc thit b ln men

- Cc thit b ha l: Chng ct, tinh luyn, trch li,...

2. Yu cu c bn i vi my sn xut thc phm

i vi my sn xut thc phm, khi thit k, ch to v s dng chng, ngoi nhng

yu cu chung ( cng, sc bn, bn rung ng) cn phi p ng nhng yu cu sau:

- Kh nng thc hin qu trnh cng ngh tin tin

- Hiu qu kinh t k thut cao

- Tnh chng mn cao

- Gi thnh h: My c kt cu n gin, vt liu ch to ra n r tin, d kim, chi

tit tiu chun ha. Sa cha, bo dng d dng, thun li

- Lm vic n nh, tin cy, m bo mi trng lm vic t bi, ting n,...

- Tui th 10 12 nm

3. Nhng vt liu chnh ch to thit b sn xut thc phm

3.1. Kim loi v hp kim

a. Gang: Ph bin nht, chim 50% kim loi trong my ch bin thc phm. L hp kim

ca Fe-C: 2-4%

u im: C tnh c cao, dng c cc chi tit phc tp nh thn my, b my, sng

trt,...Kh nng chu nn gp 4 ln kh nng chu un.

Phn loi:


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3

- Gang xm C: 2,8-3,7%. K hiu C4

- Gang trung tnh: Cng l gang xm nhng cho thm ph gia silicocanxi,

silicoalumin, felosilu. K hiu CM4

- Gang cu: Cng l gang trung tnh nhng cho thm hp kim Mg, bn rt cao, c

th c cc trc khuu ca my nn. K hiu B4- Gang r: %C thp, d gia cng

- Gang hp kim: Thm vo cc loi gang trn cc kim loi Cr, Mn, Ni, Si. Dng ch

to gung bm, v bm chu axit, ng dn chu cc mi trng khc nhau

b. Thp: C c tnh, kh nng gia cng c cao. Ty theo phng php nhit luyn cho

nhng thp c c tnh khc nhau, rt cao. C 3 nhm:

- Thp cacbon : CT3, CT5.

Thp 45, thp 50Thp dng c

- Thp hp kim: Cao, Thp

c. ng: Khng bn trong mi trng c Cl, Br, I, NH3, H2S. Dn in, dn nhit tt, d

dt mng, ko si. Dng nhiu trong cng nghip ru bia, cc loi thp,...

ng : - Thau

- Thanh. Hp kim Al, Si, Sn

d. Nhm: Chu cc mi trng HNO3 m c,CH3COOH3.2. Phi kim loi

a. Ngun gc v c:

- granit: granit + andezit + thy tinh lng gi l matit: chu axit

- Amian: Dng lm m chu nhit, lm b chng chy, bo n

- Thy tinh

- Gm

b. Ngun gc hu c:- Cao su: 2-4%S: Cao su mm, dng lm m, cc khc ni trc

20-40%S: Cao su ebonit

- Faolit: L hn hp ca phenol formuldehyt + amian. bn cao, lm cc ng ng

dn, thng cha, my bm

- Ngoi ra cn c nha PVC, PP,...


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4

CHNG 1. CC MY V THIT B VN CHUYN

1. Khi nim

My v cc thit b vn chuyn ng vai tr quan trng trong dy chuyn sn xut

cc sn phm thc phm, lin kt cc h thng cng ngh trong dy chuyn sn xut, vnchuyn nguyn liu t kho cha n dy chuyn sn xut v vn chuyn sn phm v kho

cha ...

Phn loi: Theo phng thc lm vic c hai loi:

- Loi vn chuyn lin tc: Bng ti, vt ti, gu ti, cc thit b vn chuyn vt liu bng

khng kh, bng thy lc,...

- Loi vn chuyn gin on: Cu, palng, cu trc, thang my,...

Trong cc nh my sn xut v ch bin lng thc thc phm, vn chuynnhng vt liu ri, vt liu ng ti, nhng kin hng hoc nhng vt liu n chic theo

phng nm ngang, thng ng hoc nghing, ch yu dng my v thit b vn chuyn

lin tc. Khc vi loi lm vic gin on, nhng my v thit b vn chuyn lin tc c

th lm vic trong mt thi gian khng gii hn, chuyn ch vt liu theo mt hng

nh khng dng li khi np liu v tho liu. Nh vy nng sut ca chng tng i ln

hn so vi cc my v thit bi vn chuyn gin on

Cc my v thit b vn chuyn lin tc hin nay c th chia ra hai nhm chnh:

- My c b phn ko: Bng ti, xch ti, co ti, gu ti,ni ti, gi ti- My khng c b phn ko: Cc loi vt ti, cc my vn chuyn qun tnh, cc h

thng vn chuyn bng khng kh v thy lc

chng ny chng ta s kho st mt s my v thit b vn chuyn lin tc c

dng ph bin trong cc nh my sn xut v ch bin lng thc thc phm trong v

ngoi nc

2. Cc thit b vn chuyn c hc

2.1. Bng ti2.1.1. Cng dng

Trong cc my vn chuyn lin tc th bng ti l loi c dng nhiu nht

u im: An ton cao, cu to n gin, bn

C kh nng vn chuyn vt liu ri v n chic theo cc hng nm ngang,

nm ngang v kt hp c hai


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Vn u t v ch to khng ln

C th t ng ha

Vn hnh n gin, bo dng d dng

Lm vic khng n

Nng sut cao, tiu hao nng lng tNhc im: Phm vi s dng ca bng ti b hn ch v:

- Chng c dc cho php khng cao, thng t 16-240 ty theo vt liu

- Khng th vn chuyn theo ng cong

- Khng vn chuyn c vt liu do, dnh kt

2.1.2. Cu to v phn loi bng ti:

Hnh 1.1. Bng ti c nh

Bng ti gm c tm bng (3) kn un cong trn tang dn (5) v tang cng (1). Tm

bng va l b phn ko, va l b phn ti liu. Chuyn ng c nh lc ma st xut

hin khi tang dn quay. ng c (9) cng vi hp gim tc (8) v cc ni trc l cc c

cu truyn ng ca my. Phu (2) np vt liu, phu (6) tho vt liu. B phn co

(7) lm sch tm bng.Tm bng c cng s b nh b phn cng (10) lp tang cui my hoc lp

nhnh khng ti. Tt c cc cm my nu trn u c lp trn mt khung .

Khi my lm vic, tm bng dch chuyn trn cc gi trc ln (4), (11) mang theo vt

liu t phu np liu n phu tho. Qu trnh tho liu tin hnh tang u my


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Sau y l s phn loi cc bng ti dng trong cc nh my lng thc thc

phm.

Hnh 1.2.S cc bng ti c nh

a) nm ngang; b,c, d) c ng vn chuyn phi hp; ) c xe tho liu; c) lu ngVn tc chuyn ng ca bng ti khi vn chuyn cc ht c cho bng 1.1 v

bng 1.2


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Bng 1: Vn tc chuyn ng ca tm bng i vi bng ti nm ngang

Vt liu vn chuyn Vn tc chuyn ng ca tm bng m/s

Thc, go, u, la m

Ng, i mch, kiu mch

Ht hng dng

Ht bng

ht u nnh

Ng bp

Ht gy

Tru v ph liu ca ht

Bao bt, hng ng kin

2,5 4,5

2,0 2,5

1,5 2,0

2,5 3,5

1,5 2,0

0,8 1,2

1,5 2,0

0,8 1,2

0,6 1,2

Bng 2: Vn tc v nng sut ca cc bng ti c nh khi vn chuyn cc loi ht c

khi lng th tch 0,75l/m3

400 500 600-650 759-800 900-1000 1100- 1200

Vn tc tm bng m/sNng sut, T/h

2,550

3,5100

3,5175

4,5350

4,5500

4,8800

2.2 Gu ti

2.2.1. Khi nim: vn chuyn nhng vt liu ri ( dng bt, ht, cc nh) i theo

phng thng ng hoc nghing trn 500 ngi ta dng gu ti

2.2.2. Cu to v nguyn tc lm vic

a. Cu to: Gu ti gm nhng b phn sau:

- B phn ko di v tn mang nhiu gu v un vng qua tang (hoc a xch) trn vdi ca my

- Chn my gm c tang (hoc a xch), trc lp tang, v v hp np liu

- u my gm c trc dn ng, tang (hoc a xch), b phn truyn ng v b phn

tho liu


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- Thn my gm nhiu on ng c tit din trn hoc ch nht ni vi nhau bng bch,

nm vo khong gia u v chn gu ti, bao kn b phn ko

Hnh 1.3. Hnh dng chung ca gu ti

1) Bng; 2) gu; 3) tang u my; 4) tang chn my; 5) b gu ti 6) phu np liu

7) b phn cng 8) ca quan st 9) trc u my 10) u gu ti 11) ca tho liu

b. Nguyn tc lm vic: Khi my lm vic th gu xc vt liu khu vc chn my v

vn chuyn ln pha u my. y, di tc dng ca trng lc v lc qun tnh, vt

liu c t gu vo b phn tho liu ri t chuyn ti ni s dng

Vt liu ri c vn chuyn bng gu ti gm nhiu dng: dng bt (hoc bi), dng ht,

dng cc

u im: - Cu to n gin, kch thc chim ch nh


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- C kh nng vn chuyn vt liu ln mt cao kh ln (50-70m),

- Nng sut cao (700m3/h)

Nhc im: - Nu vt liu vn chuyn ln gy va p, d sinh ting n

- D b qu ti nu tip liu khng u, nn cn np liu mt cch u n

- Khng tho liu c gia chng, np liu v tr ty thch.2.2.3. Phn loi:

- Theo cu to ca b phn ko: c 2 loi:

Gu ti dng bng: c dng ph bin vn chuyn nhng vt liu ri trong cc kho

lng thc, cc nh my xay bt, nh my xt go, nh my ch bin thc n gia sc, nh

my bnh m, nh my p du, nh my sn xut tinh bt, nh my bnh ko, nh my sn

xut m si v cc nh my thc phm khc.

Gu ti dng xch: (mt hoc 2 dy xch): ch yu dng vn chuyn nhng vt liudng cc v nhng vt liu gy tc hi cho tm bng ( nh vt liu nng)

- Theo phng php tho liu: c 3 loi gu ti:

Gu ti tho liu di tc dng ca trng lc

Gu ti tho liu di tc dng ca lc li tm

Gu ti tho liu di tc dng ca lc kt hp ( lc li tm v trng lc).

2.3. Vt ti:

2.3.1. Khi nim: vn chuyn nhng vt liu ri theo hng nm ngang, nghing hoc thng ng,

trong cc nh my thc phm, ngi ta dng vt ti.

Trong cc vt ti, vt liu c vn chuyn tng t nh mt ai c chuyn ng

dc theo inh c quay. Vt ti gm c mt mng c nh v mt trc vt. Khi trc vt quay

lm cho vt liu chuyn ng tnh tin theo mng.

u im :

- Chim ch t: Vi cng nng sut th din tch tit din ngang ca vt ti nh hn nhiu

so vi cc my vn chuyn khc.

- S lng bi v cc chi tit chu mi mn khng nhiu nn d vn hnh thao tc.

- B phn cng tc nm trong mng kn nn c th ni mng vo v tr no ca h

thng thng gi.

- Tc quay ca trc vt tng i ln.


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- Gi thnh thp.

Nhc im :

- Chiu di vn chuyn v nng sut b gii hn. Chiu di ln nht ca vt ti thng

khng qu 30m vi nng sut ti a l 100T/h.

- Ch vn chuyn c nhng vt liu tng i ng nht.- Vt liu b o trn mnh, mt phn b nghin nt hoc b phn loi theo khi lng

ring. V vy ngi ta khng th dng vn chuyn thc n gia sc ch bin.

- Tiu tn nhiu nng lng hn bng ti.

2.3.2. Cc loi vt ti

2.3.2.1. Vt ti nm ngang

Hnh 1.4. Cc vt ti

a) s vt ti nm ngang:

1. mng; 2. gi trc treo; 3. trc; 4. cnh vt; 5. thnh mt u; 6.ng np liu;

7,8. ng tho liu; 9. Van an ton; 10. C cu truyn ng

b) hnh dng trc vt

c) cc loi cnh vt khc nhau v chiu quay ca chng

a. Cu to v nguyn tc lm vic:

Trong mng c nh 1 ti phn trn c lp nhng gi trc treo 2 lm ch cho trc 3.

Trc c hoc rng v trn sut chiu di ca n c gn cnh vt 4. v tr gi trc treo,

cnh vt b gin on 1 khong bng chiu di gi trc. Mt u 5 ca mng c bt kn.

Vt liu vo phu np liu 6, i ra ng tho liu 7 v 8 dc theo vt ti. y (6,7 v

8) c cc van chn c th thay i kch thc ca np v tho. Cui vt ti c van an

ton 9 tho vt liu khi qu y. C th thay bng ng chy trn lp gn ca tho liu.

a

b

c


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Ty theo cch b tr cnh vt trn trc m vt ti c th l phi hoc tri ( hnh 1.4.c).

C nhng vt ti gm 2 phn trong c 1 phn l phi, 1 phn l tri.

Cc vt ti ny dng vn chuyn hai dng vt liu theo hng ngc chiu nhau.

Nhng vt ti c cnh c lm bng thp l ch dng vn chuyn vt liu kh v ti.

Mun vn chuyn nhng vt liu cc hoc dnh phi dng vt ti dng bng (hinh 1.5). vn chuyn nhng vt liu vn cc (ht m, tinh bt, hp cht thc n gia sc) th dng

cnh vt dng bi cho ( hnh 1.6)

Hnh 1.5. Cnh vt dngbng.

1.6. Vt ti dng bi cho

Mng ca vt ti gm nhiu on t 2m n 4m, ni ghp vi nhau bng bch v

bulng. Nu vt ti di qu 3,5 m th phi lp nhng gi trc trung gian (thng l gi trc

treo) ci ny cch ci kia 3m. Trong cc nh my lng thc thc phm ch nn dng vt

ti c chiu di khng qu 15m. Nu cn vn chuyn theo di ln (30m) th nn lp

ng trc hai vt ti c hai b phn truyn ng i u nhau.

2.3.2.1. Vt ti thng ng

Khi nim: Vt ti thng ng dng vn chuyn vt liu ri v vt liu dng cc

nh (ht, bt, thc n gia sc, cc loi c). Cng c th dng loi vt ti ny vn


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chuyn cc vt liu n chic. Chiu cao khng qu 12-15cm nng sut 80-100 m 3/h (vi

D cnh vt 300mm)

u:

- Tit kim din tch

- Tho liu theo hng ty , v tr trung giantheo chiu cao thn my.

Nguyn tc lm vic:

Vt liu c a vo trc vt thng ng

trong v tr kn, nh ma st vi cnh vt m thc

hin chuyn ng quay. Di tc dng ca lc li

tm vt liu c p st vo b mt trong ca

mng.

Ma st gia vt liu vi mng lm cho qu

trnh quay ca vt liu b hm bt nn tc

vng ca n gim. Kt qu vt liu trt theo b

mt xon c v c nng dn ln pha trn.

3. Vn chuyn vt liu bng khng kh

3.1. Khi nim:Vn chuyn vt liu bng khng kh da trn nguyn l li dng kh nng chuyn

ng ca dng kh trong cc ng dn, vi tc nht nh mang vt liu t ch ny ti

ch khc di trng thi l lng. V l thuyt th c th dng khng kh vn chuyn vt

liu ri c khi lng v kch thc ht bt k. Nhng nng lng vn chuyn v tiu

tn tng nhanh rt nhiu ln so vi trng lc ca ht vt liu, nn thc t phm vi ng

dng ca phng php ny b hn ch.

Mun lm cho hn hp khng kh v cc ht vt liu chuyn ng c trong cc ng

dn th cn phi to c chnh lch p sut 2 u ng, ni cch khc l phi to ra p

lc. p lc c to thnh bng cch gim p sut ca khng kh hoc tng p sut ca

khng kh.

3.2. Phn loi:

Theo tr s p sut to thnh c th chia ra:

Hnh 1.7. Vt ti thng ng


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- Cc h thng p sut thp, trong tn tht p sut khng vt qu 5.10 3N/m2.

- Cc h thng p sut trung bnh, trong tn tht p sut khng vt qu 104N/m2

- Cc h thng p sut cao trong tn tht p sut ln hn 104N/m2.

Hnh 1.8. Cc s nguyn l:

a) ca h thng ht vi p sut trung bnh vn chuyn bt

b) ca h thng ht vi p sut cao

c) ca h thng y vi p sut cao

3.2.1. Cc h thng vn chuyn bng khng kh vi p sut thp v trung bnh:

Trong cc nh my lng thc thc phm cc nc, h thng p sut thp v trung

bnh c s dng rng ri c gii ha cc cng on vn chuyn trong phn xng


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v gia cc phn xng vi nhau, cho php kt hp vi 1 vi qu trnh cng ngh nh

lm lnh, phn loi, sy..v..v..

hnh 1.8a l s nguyn l ca mt h thng ht v p sut trung bnh dng vn

chuyn bt t thng cha ti kho cha. Bt do t 1 ch n c tho vo thng cha

2, t y bt i theo ng dn 3 vo b phn tho liu 4 t pha trn mng 5, mng ny s

phn b bt xung cc kho cha 6 nh qut 7.

T b phn tho liu khng kh c dn vo xycln 8 ri vo my lc ti 9 lm

sch. T my lc khng kh sch vo qut 10 v ra ngoi tri. H thng ny lm vic vi

nng hn hp = 4,5 5,0 kg/kg v vn tc khng kh 18-20 m/s

3.2.2. H thng vn chuyn bng kh vi p sut cao:

hnh 1.8b l s mt h thng vn chuyn vi p sut cao bng phng php ht.

Chn khng trong mng c to thnh bi my thi kh 1. Khi nhng vi ht 2 vo trong

khi ht th khng kh c ht vo, ko theo ht v vn chuyn n trong ng dn 3.Mun x dch c ng dn d dng cn c nhng on ng mm 4. Qua ng dn ht i

vo b phn tho liu 5. Ht c tch ra khi b phn tho liu nh van cng 6. Khng

kh theo ng dn 7 a i lm sch bi xycln 8 v my lc ti 9 ri vo my thi kh

v thot ra ngoi.


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PHN 2

CC THIT B C HC

CHNG 2: CC MY LM SCH V PHN LOI .

2.1 Khi nim chung :

- Trong Cng ngh sn xut thc phm thc phm, nguyn liu a dng v

chng loi, kch c, thnh phn khc nhau .Trong qu trnh thu hoch b ln nhiu tp

cht. Do , m bo cc iu kin cng ngh ch bin m bo cht lng thnh

phm, gi tr cm quan v..v, nguyn liu trc khi ch bin cn phi qua khu lm

sch v phn loi

Mc ch ca qu trnh phn loi :

* m bo cht lng nguyn liu : ng nht v kch c, thnh phn

* Tng thi gian bo qun

* Thch hp cho cc cng on ch bin tip theo

C s phn loi: C s ca qu trnh phn loi da vo hnh dng, kch thc, chiu

di, tnh cht kh ng, tng tc b mt, tnh cht t tnh v..vv, mi loi mt my

ring

V d : Phn loi mu sc: c t bo quang in

Phn loi kch thc: sng, my chn ht.

Phn loi theo tng tc b mtPhn loi theo khi lng ring : my gn

Tch tp cht l : Nam chm in, nam chm vnh cu

2.2. Phn loi theo c tnh hnh hc:

2.2.1. Khi nim: Phn loi theo c tnh hnh hc c s dng rt ph bin trong

cc x nghip lng thc tch tp cht hoc xp loi nguyn liu, bn thnh phm

v thnh phm. C s phng php ny l da vo s khc nhau v chiu dy, chiu

rng, chiu di, hnh dng v tit din ca cc phn t trong khi ht lng thc,

thnh phm phn loi. i vi dng ny ngi ta dng my phn loi theo kiusng.

2.2.2. Sng:

Sng l phng php ph bin v n gin nht phn loi nguyn liu v

sn phm trong cc nh my ch bin bt go v x nghip ch bin thc n hn hp

cho gia sc .


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T "sng " dng trong trng hp l phn loi c kch thc ln v "ry" dng

trong trng hp l phn loi c kch thc nh.

Vic phn loi ht c th tin hnh theo 2 cch:

- Phn loi kch thc t nh n ln (hnh 2.1): Ti y cc mt sng c xp nitip nhau. Mt sng c kch thc l nh c t trc, kch thc l ln t sau.

Khi hn hp vt liu chuyn ng t tri sang phi ta s thu c s phn loi nh

mong mun.

- Phn loi kch thc t ln n nh (hnh 2.2): Ti y mt sng c xp song

song v chng ln nhau. Mt sng c kch thc l ln dt ln trn, kch thc l nh

t di. Khi hn hp vt liu chuyn ng t trn xung ta s thu nhn c s

phn loi nh mong mun

Hnh 2.1.Phn loi theo kch thc t nh n ln Hnh 2.2.Phn loi theo kch thc t ln n nh

Cc b phn chnh ca sng

Mt sng l b phn lm vic chnh. Cc vt liu trn mt sng phi c chuynng tng i trn mt sng. Nhng vt liu phi c kch thc nh hn kch thc

l sng c th lt xung l th sng qu trnh phn loi mi c tin hnh.

Cu to: C 2 loi tm c l, li an v thanh ghi .

- Mt sng c l: L cc tm kim loi: thp hay ng, trn c cc l c din tch

khc nhau: trn, thun di (vung), tam gic. Din tch cc b mt t do phi c t l

hp l so vi tng din tch mt sng, do mi m bo bn c kh .

l

chiu dy 1,5

Tuy nhin chiu dy ti a ca mt sng khng vt qu 12mm. Mt sng dng

phn loi cc vt liu c kch thc > 5mm. Cc l trn mt sng c kch thc t

5-80mm c b tr song song hay xen k nhau. Cc l hnh ch nht c chiu di

gp 3 ln chiu rng.


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u im ca mt sng ny l bn, thi gian s dng di nhng n c nhc im l

b mt t do nh.

Mt sng c l vi hnh dng v kch thc khc nhau .

Trong qu trnh phn loi, hn hp c chia lm 2 phn :- Phn lt qua sng gi l cu t lt sng (CTLS)

- Phn nm li trn sng gi l cu t trn sng (CTTS)

Tm sng c l c ch to t l kim loi dy khong 0,8-1,0 mm.

Ty theo kch thc l sng ngi ta chia sng thnh nhiu s. S hiu ca sng

l t l s tng ng vi kch thc l sng ( tnh bng mm) nhn vi 10.

Th d: Sng t l thun di, chiu rng l 1,75mm th mang s hiu 17,5 (No

17,5).

- Mt sng an( hnh 2.3): Dng cc si vi, si kim loi, si la hoc si nha tnghp an li vi nhau theo mt kch thc nht nh. Mt sng bng si kim loi c

an thnh cc l dng vung hoc ch nht kch thc cnh l t 5mm n

0,4mm. u im ca loi mt sng ny l c b mt t do ln nhng nhc im l

khng bn.

S hiu ca mt li sng an bng si kim loi l s tng ng vi kch

thc cnh l sng tnh bng mm

V d : i vi sng l vung cnh D = 0,4 mm mang s hiu 0.4 (No =04 )

- Ry :

i vi sng an nu kch thc l > 0,2mm gi l mt sng an

i vi sng an nu kch thc l < 0,2 mm gi l ry

Lin X mt ry la c chia lm 2 loi: Ry nh v ry nng ty theo

khi lng 1m2 mt ry .

Ry nng: C 20 con s ( t s hiu No 71 n No 280 )

Ry nh c 25 con s ( t s hiu No 7 n s hiu 76)

i vi ry nng s hiu v d No71 ngha l trong 10cm c 71 hng li vi ry nh s hiu No 76 ngha l 1cm c 76 hng l. Ry nh phn

loi bt, ry nng phn ht ln hn v d : Go, Cm.

Gn y ry la c thay bng ry an t si kapron hoc nylon, ry an

bng si nhn to bn gp 3 ln, t ht m v hu nh khng lm tc l ry

- Thanh ghi ( hnh 2.4):


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Loi ny dng phn loi cc loi vt liu c kch thc ln hn hn 80mm.

Cu to mt sng gm cc thanh ghi c c theo chiu dc sang, khe h gia

chng bng kch thc vt liu lt qua sng.

Hnh 2.3 . Cc dng mt sng li an

Kch thc ca thanh ghi c chn ph thuc kch thc ca sn phm cha

sng. Vi H = d v B = (0,2-0,3) d. Cc cnh nghing c gc nghing khong 6-100

Ch lp t phn chiu rng thanh ghi c kch thc nh hn lun lun quay xungdi .

2.2.3. Phn loi cc my sng

a.Theo cu to ca b phn lm vic : My sng chia lm 2 nhm .

- Mt sng phng: c dng ph bin nht v c h s s dng b mt lm

vic ca li cao nht. C 3 loi : My sng c li chuyn ng tnh tin qua li,

my sng c li chuyn ng trn, my sng c my chuyn ng rung (hnh 2.5).

Hnh 2.5. S cu to cc loi sng phng

- Mt sng hnh tr: kim tra ph liu ca ht.

Hnh 2.4 . Hnh dng cc thanh ghi ca sng


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b. Theo iu kin s dng : Sng c nh

Sng lu ng

c. Theo s lng mt sng: Sng n

Sng kpd. Theo hnh thc dn ng :

My sng dao ng qun tnh

My sng dao ng bng c cu lch tm .

My sng dn ng bng tay quay thanh truyn

e.Theo vt liu cn sng:

My sng tp: Dng tch tp cht.

My sng phn loi: phn ring cc thnh phn ht

c kch thc v cht lng khc nhau.

2.2.4. My sng c mt sng phng chuyn ng tnh tin qua li :

c dng ph bin nht in hnh l my sng phn loi bng li sng v

khng kh .

Cu to: Hnh 2.6 l cu to ca mt my sng phn loi bng li sng v

khng kh dng lm sch v phn ring ht. Theo chiu cao ca my c th chia

thnh 3 phn:

- Vng phn loi bng khng kh lm sch ht .- Thng sng phn ht theo ln thnh 3 phn ht ring bit .

-Vng phn loi bng khng kh chia tng ht theo ln thnh cc phn

ring theo tnh cht kh ng hc .

Nguyn tc lm vic: Ht vo bung 1, qut 2 ht khng kh ko sn phm

vo ng 3 v cun theo cc hn hp nh i vi kh ng lc. Nhng hn hp ny

c lng vo bung 4 v t y chng c tch ra khi my. Khng kh sch

bung 4 c qut thi vo ln th 2 lm sch ht. Nh vy qut lm vic theo

nguyn tc tun hon kn ca dng khng kh. thng sng 5 khi ht c phn ra mt s thnh phn ht khc nhau theo

chiu rng v chiu dy ca ht. Tt c vo nhng ngn khc nhau ca vng phn

loi bng khng kh pha di. Qut 6 ht khng kh qua lp sn phm ang trt

theo mt phng nghing 7. Tng ng vi cc vn tc ca khng kh khc nhau ti


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nhng ngn ring ca bung lnh, c cc hn hp khoang, ht bn, ht sch v hn

hp nh c lng xung

Hnh 2.6. Cu to my phn loi bng li sng v khng kh

2.2.5. My sng rung .

Mc ch s dng : - Phn loi nguyn liu

- Vn chuyn vt liu

- Lm ti v ngui vt liu

Phn loi: C 2 c cu gy rung ng cho my sng rung

- a c gn i trong .- C cu lch tm

* a c gn i trong: c gn trn trc dn ng ca my. Khi trc quay

cc a ny gy nn cc lc qun tnh lm cho thng sng chuyn ng theo cc

hng khc nhau.


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Cu to v nguyn tc lm vic:

1- thng sng

2,3- l xo xon

4- trc dn ng5- i trong

Hnh 2.6. S ca mt my sng rung

Hnh 2.6 l s ca mt my sng rung. C cu gy rung ng l a c gn i

trng. li trn, cc tp cht ln c tch ra, cn li di l cc tp cht nh

Thng sng 1 c gn li sng t trn bn l xo xon thng ng 2,3. Cc chi tit

lp ghp cc l xo vi thng sng, cho php iu chnh mc ko cng ca chng.

Ti trng tm ca thng sng c trc 4 trn c gn i trong 5. Khi trc mang i

trng quay th trng tm ca thng sng chuyn dch tng i vi trng tm caton h, cn trng tm ca ton h th ng yn .

* C cu lch tm: Trc lch tm ca my c ta trn cc gi . Cc gi ny

li c gn vo thng sng. Khi my lm vic thng sng s thc hin chuyn ng

rung nh s quay ca trc lch tm.

S cu to my sng rung c cu lch tm c trnh by trn hnh 2.7

Hnh 2.7. S cu to my sng rung c cu lch tm

1. B my; 2. L xo; 3. Khung sng; 4. i trng gy rung; 5. a quay6. trc lch tm 7. Bnh ai dn ng; 8. li sng

My gm c khung sng 3 c bng h thng l xo gn trn b my 1.

Trn khung sng 3 cn gn ca trc lch tm 6. Pha ngoi trc lch tm 6,

ngi ta b tr hai a 5 m vnh ca n c gn hai i trng. Vi cch lp ny, c th

iu chnh bin dao ng ca sng. Trc lch tm nhn truyn ng quay qua


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bnh ai dn ng 7 t ng c vo. Trn khung sng c th t 1,2 hay nhiu li

sng 8 ty theo yu cu phn loi

Tnh ton :

Nng sut ca my sng rungXc nh theo cng thc

Q = Bq, kg/h

Trong : B - Chiu rng ca mt sng, cm

q - Ti lng ring ca mt sng kg/cm gi

Chiu di ca mt sng :

L =btpv

q

36, m

Trong : p : Khi lng ring ca vt liu em sng kg/m3

vtb: Vn tc trung bnh ca cc phn t vt liu c th ly bng

0,003 - 0,004m/s.

2.3. Phn loi theo nhng tnh cht kh ng hc

Trong cc x nghip ch bin bt, go v thc n hn hp cho gia sc thng

dng kh ph bin cc thit b phn loi hn hp bng dng khng kh. l phn

loi bng sc gi, da vo tnh cht kh ng hc ca cc cu t phn chia thnh

cc phn khc nhau.

Nhng tnh cht kh ng hc ca phn t ph thuc vo hnh dng, kch thc,

khi lng, trng thi b mt ca phn t, v tr ca phn t trong dng khng kh v

cui cng l trng thi ca khng kh..

Kh nng chng li sc y ca dng khng kh gi l cn gi ca phn t.

Nu cc phn t c cn gi khc nhau th vn tc ca chng khc nhau. Da vo

s khc nhau c th phn loi hn hp .

nc ta, Trung Quc, Nht Bn .v..v. cn dng qut hm tch cc tp

cht nh v nng trong khi lng thc da vo nguyn tc phn loi theo tnh chtkh ng hc trn (hnh 2.8).


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Hnh 2.8. S t hp 3 qut hm tch tp cht nng v nh

a. trng hp trong thc c t sib. trng hp trong thc c nhiu si

2.4. Phn loi theo t trng.

cc nh my ch bin go, bt v thc n gia sc th qu trnh lm sch v

cc tp cht nng nh: , si, t vin, mnh thy tinh v..v. rt quan trng . Chng

c kch thc gn bng kch thc ca ht nn khng th phn loi bng sng .Do

phi phn loi v s khc nhau v t trng .

Nu cc cu t trong hn hp cn phn loi c s khc nhau r rt v t trng

th cng d dng phn ring ra .My tch tp cht si da trn nguyn tc phn loi theo t trng. S qu

trnh cng tc ca my tch c gii thiu hnh 2.9

mt s nh my, cn dng ph bin loi my tch kiu Grigorovic. B

phn cng tc chnh ca my tch ny l nhng a trn hnh cn .Khi my chuyn


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ng lc trn, di tc dng ca lc li tm qun tnh, ht chuyn ng ln pha trn

ca a hnh chp, cn si chuyn ng xung di ( hnh 2.10).

Hnh 2.9. S my phn ly si 2.10. S cng tc ca mt my tch

1. Phu np liu 1.Phu np liu 2. Mt sng;

2. My lng 3. B phn iu chnh gc nghing

3. Sng 4. Phng khng kh; 5. Qut

2.5. Phn loi theo t tnh .

2.5.1 Khi nim: Cc nguyn liu thnh phm a vo nh my thng c ln

tp cht kim loi, nht l st, do qu trnh thu hi, vn chuyn hoc lc lm sch .

Tp cht st c th lm hng b phn cng tc ca my (c b mt trc nghin,

my xay,v..v..) v c th bt tia la - gy ha hon . Do lm sch tp cht st lmt khu c ngha quan trng ca qu trnh sn xut. Cc loi tp cht st, gang,

niken u c th dng nam chm tch ra c .

2.5.2 Thit b

Dng nam chm vnh cu hoc nam chm in tch cc tp cht st (hnh

2.11, hnh 2.12) .

Thit b phn loi bng t tnh gm: Nhiu thi nam chm ghp li, cc nam

chm b tr trn mt phng nghing m sn phm chy qua. Sn phm chy qua nam

chm thnh lp mng vi vn tc khng ln lm nam chm ht li cc tp chtst. Sau mt thi gian lm vic cn lm sch b mt nam chm.

i vi nam chm vnh cu phi m bo lc ht khong 12 kG. Lp nguyn

liu chy qua nam chm khng c qu dy.


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Hnh 2.11. S thit b nam chm vnh cu Hnh 2.12. My phn loi bng nam chm in

2.6. Phn loi theo tnh cht b mt nguyn liu .

2.6.1 Khi nim: Cc cu t khc nhau trong khi ht c trng thi l b mt

khng ging nhau. B mt ca chng c th x x, r, nhn, c v, khng v v..v..

Nhng trng thi b mt khc nhau y c th p dng phn loi trn b mt phng

nghing .

2.6.2. Nguyn tc ca cc thit b phn loi theo tnh cht b mt nguyn

liu (hnh 2.13):

Khi cc phn t b mt trng thi khng ging nhau chuyn ng trn b mt

phng nghing th chu tc dng ca lc ma st khc nhau. Do , cc phn t y dchchuyn vi nhng vn tc khc nhau. V vy, cui mt phng nghing, chng s ri

cc v tr khc nhau. Nu t trn qu o ri nhng tm chn th c th phn loi

hn hp ra lm nhiu phn khc nhau theo h s ma st.

Phng php phn loi da vo s khc nhau v h s ma st c ngha rt ln

trong trng hp phn loi hn hp gm 2 hoc nhiu dng ht c kch thc gn

nhau

Hnh 2.13. S d nguyn l phn

loi theo tnh cht b mt nguyn

liu


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2.7. Cc my phn loi khc :

My phn loi da theo chiu di ht: (My chn ht)

2.7.1. Mc ch:

- phn ring cc sn phm thc phm ri xa hoc tch cc tp cht theo chiu diht (nh p du, men ...).

- Chn ht ging tc cc tp cht rm r tch cc tp cht ngn nh: sn, ct, tm tch

go xay ra khi thc .v.v...

2.7.2. Phn loi:

c 2 loi - My chn ht kiu tr.

- My chn ht kiu a.

2.7.3. My chn ht kiu hnh tr(hnh 2.13a, hnh 2.14)

Cu to : My gm ng tr bng thp 1 (v thng), b mt bn trong ca v

thng c nhng l t ong 2 v vt ti 3, t trong mng 4 .

ng tr c ch to bng thp tm, nhng l t ong c ng knh > 3mm

thc hin bng phay cc tm thp hoc km.

Nguyn tc lm vic: Khi ng tr quay th nhng ht ring l ri vo cc t

ong, nhng ht ny cng quay vi ng tr 1 gc no ri ri xung. Ht ngn c

lt vo trong l t ong su hn ht di. V vy khi ng tr quay, cc ht ngn ri

xung mun hn ri vo mng v c tho ra bng vt ti . Nhng ht di trc theo

b mt bn trong ca v thng dc theo chiu di ca thng. Mc phn ring hn

hp ht trn ph thuc vo tm t mt cnh trn 5 ca mng 4.

2.7.4.My chn ht kiu a (hnh 2.13.b):

Cu to v nguyn tc lm vic: Cc l t ong 7 nm trn b mt a gang

quay 8. Khi a quay cc ht ngn ri vo bn trong cc l t, sau ri xung mng

6 v c tho ra khi my .Cn ht di trt theo chiu nghing ca my.

Hnh 2.13. Nguyn tc lm

vic ca my la chn c ht

a. Kiu hnh trb. Kiu a


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Hnh 2.14. My chn ht kiu tr


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CHNG 3

CC THIT B LM NH

3.1. My nghin:

3.1.1. Khi nim :

Trong cng nghip sn xut lng thc thc phm thng gp qu trnh nghin

nh vt liu t cc cc to, cc ht thnh dng bt th, va hoc bt mn .

V d : CN xay bt hn hp, nghin ht ng cc thnh bt

CN thc n gia sc: nghin ht, c kh v cc cht b sung khc (mui, nguyn

t vi lng, vitamin, khng sinh), thnh bt, nghin th kh du, li ng v.v...

CN bnh ko : nghin bn TP: Cacao vn, bt nho scola, nghin bt,

nghin ng .CN tht c : Nghin xng, nghin bt c .

CN SX du bo : Nghin ht c du, nghin kh du .

CN ln men : Nghin i mch, mm ht ti, mm ht kh v.v ...

Qu trnh nghin nh vt liu trong cc my nghin l nh cc lc c hc. C th

phn loi cc dng tc dng c hc nhm ph v vt liu em nghin nh (hnh 3.1).

Ty theo kt cu ca tng loi my nghin m lc ph v vt liu em nghin c th l

lc nn, p, ch, b, ct, x, p trt, va p hoc do mt vi lc trn cng tc dng

ng thi. Cng nghin ph thuc:

- Lc tc dng kt cu my cc c cu truyn ng.

- Tnh cht c l ca vt liu em nghin nh cng m, tnh cht ca v ht.

Hnh 3.1. Cc lc nghin

a )nn p; b)ch; c) b; d)ct

) x; e) p trt; g) p


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3.1.2. Cc loi my nghin.

Cc loi my nghin nghin nh bng mt hoc vi dng tc dng c hc nh

m t hnh 3.1. Cc loi my nghin gm c: My nghin a, my nghin trc,

my nghin chu con ln, my nghin ba, my nghin bi v.v... Ty theotnh cht c

l hnh dng, m ca nguyn liu em nghin, yu cu ca sn phm, nng xut,cng sut, tnh cht cng ngh ca cng on tip theo (kh t ) m chon my nghin

ph hp v kinh t nht .

3.1.3 My nghin a.

Trong CNLTTP dng my nghin a nghin bt va v mn. Hin nay t

dng do nng sut thp.

Phn loi c 4 dng my nghin a :

- My c trc thng ng lm quay a trn .

- My c trc thng ng lm quay a di .

- My c trc nm ngang lm quay 1 a .

- My c trc nm ngang lm quay 2 a.

Cu to: B phn chnh ca my nghin a l a nghin ch to bng kim loi

hoc bng nhn to .

Bng kim loi c th bng thp c hoc bng gang.

a bng nhn to gm cc thnh phn c trnh by bng 3.1

Bng 1: Thnh phn a nghin bng Thnh phn %

Loi mt Btnhm

Silic Thch anh ManhditMagiClorua

Bt nhm 70 15 15

Bt t nhm 40 30 15 15

Silic 70 15 15

Thch anh 70 15 15

Ch to a nghin cn m bo cc yu cu.

- B mt nghin cn c cng cao, nhm ln .

- C tnh ng u trn ton b b mt a nghin, khi lm vic th mn u

khng b st m.


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Do lc lin kt ca a km hn a kim loi nn phi lm thm ai thp. a

c vn tc vng 10m/s. i vi trc quay thng ng 18m/s i vi trc quay nm

ngang a gang th 28m/s cn a thp c t 68m/s.

tng kh nng nghin ca a tng bt ra khi khe nghin v tng khong

cch thng gi ngi ta gia cng mt a thnh cc vnh, cc rnh chm c profin hnhtam gic trn 2 mt a (Hnh 3.2 v 3.3).

Nng sut ca my nghin a :

Tnh theo cng thc thc nghim:

Q = 0,9 q0 = 32

2

)1(

k

kvD

Trong :

q0 : Nng sut ring trn 1m2b mt a lm vic trong 1 gi T/m2 h.

Vi thc q0 = 1,6 T/m2 h

D : ng knh ln nht ca mt lm vic ca a .m

K = D/d = 1,3 1,7, t s gia ng knh ln v nh ca a nghin .

V: Vn tc vng ca a quay, thng ly v =12,5 15m/s

Cng sut my nghin a :

Hnh 3.2.

Hnh 3.3.


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N =180

vQ ; kw.

3.1.4. My nghin trc:

Cc my nghin loi hai, ba hay nhiu trc c dng rt rng ri trong ngnh

CNTP nghin bt m, bt ng, nghin cc loi ht lm bt bn thnh phm, cc loiht c du khai thc cht bo, lm thc n gia sc, lm bnh ko v ln men.

S nguyn l ca cc loi my nghin c m t hnh 3.4 .

Vi s ny, cc loi my nghin c chung 1 nguyn l lm vic l nghin nt

vt liu khi n i qua khe hp gia 2 trc nghin. Vt liu b nghin nt 1 ln nh cc

my loi I, II, III, IV, V v VI, b nghin p 2 ln cc my VII, VIII, ba ln cc

my loi X, XI, 4 ln loi IX v 5 ln loi my XII. Vi nhng loi my nghin m

mt trc thc hin c hai ln nghin nh trc 2 loi VII, trc 2, 3, 4 loi IX th vt

liu em nghin phi c tnh cht dnh v dai, sau khi nghin c cn thnh dimng. Cn vi cc loi ht th thng dng my nghin hai hoc 4 trc.

hnh 3.5a, l my nghin c 2 trc c nh dng nghin p, cn cc loi

vt liu do, nho, khng xut hin hin tng qu ti do lc p tng t ngt. My

loi ny c cu to n gin nht v cng thay i c khong cch khe nghin bng

cch x rnh trn b my dch chuyn bu lng gi trc vi b my trc khi

nghin. Nhng khi my lm vic th chiu rng khe nghin () l khng i.

hnh 3.5b, l my nghin c trc di ng c khi lm vic, nh c lp hai l

xo chu nn gia trc v b my c nh. Loi ny dng thch hp nghin vtliu dng ht cc nh. Khi qu ti, lc p tng t ngt nn 2 l xo gi trc di ng, l

xo b nn li lm tng khong cch gia 2 trc thot lp vt liu ang gy ra qu ti.

Khi ht hin tng qu ti, lc p tr li bnh thng, 2 l xo li y trc di ng tr

v v tr c vi khe h () lm vic. Loi ny c dng rt rng ri.

hnh 3.5.c, l my nghin 2 trc, nhng c 2 trc u c lp l xo chu nn

cng di ng c khi c qu ti. My ny dng thch hp vi vt liu em nghin,

cng c kch thc khng u, d gy qu ti do lc p tng t ngt. Do kt cu phc

tp nn t dng.Di y l s lm vic ca my nghin 4 trc (hnh 3.6) :

My c hp cha liu chung phn thnh 2 ngn, trong mi ngn c hnh chp

6. Gn vi c cu thy lc t ng iu chnh khe h gia 2 trc nghin. Ht t hp

cha liu xung, quay van chn iu chnh 3 n cp trc ri liu 4 ri ht thnh lp

mng trn trc nghin quay chm 9. Mi cp trc nghin 8 v 9, nu l cp trc nhn


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th lp dao co sch, nu cp trc nghin x rnh th lp bn chi 1 co sch b mt 2

trc. my ny cn lp ng thng p 7, v tay quay 10 iu chnh bng tay

khong cch khe nghin.

Bng c cu dn ng kiu xch m thc hin c nhim v truyn ng cho

trc nghin quay nhanh v trc nghin quay chm theo chiu ngc nhau, va mbo s iu chnh khong cch gia hai trc nghin mt cch d dng .

Hnh 3.4. S nguyn l cc my nghin trc Hnh 3.5. My nghin 2 trc

Tnhton nng sut nghin l thuyt ca my nghin trc:

Xc nh theo cng thc:

Q = 3,6 . 10-6 L v tb . K (kg/h)

: Chiu rng xe nghin (mm)

L : Chiu di trc nghin (mm)

: khi lng ring ca sn phm nghin (kg/m3)

v tb =2

cn vv +

vn, vc : Vn tc vng ca trc nhanh v trc chm (m/s)


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Hnh 3.6. Cu to ca my 4 trc nghin dng nghin ht

3.1.5. My nghin ba:

Nguyn l: Qu trnh nghin nh vt liu trong my nghin ba l do va p

ca cc ba vo vt liu, s ch xt vt liu vi ba v vi thanh trong ca v my.

Cc ht vt liu nh lt qua tm li phn loi v c a ra khi my. Cn vt liu

ht to cha ng yu cu th c cc a ba tip tc nghin nh.

hnh 3.7 l my nghin ba nghin th v trung bnh c m nghin ph:my nghin c lp thm m nghin 7 trn thnh trong v my lm tng kh nng ph

v vt liu di tc dng va p ca ba v tc dng ch xt ca m nghin.

M nghin ph c t ngay di ghi 2 v tr ca np liu 1. Ghi 2 c nhim

v phn phi u theo chiu rng my, hn ch bt kh nng vng liu ln khi ba

p. Trn trc quay 3 c lp cc a treo ba 8 cch u v lch u mt gc. Trn mi


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a 8 c treo hai ba 4, cc hng ba ny p trn cc mt phng qua cc khe ghi 2

theo sut b rng ca my. Vt liu sau khi c nghin nh s lt qua li 6 ra

khi my, cn cc cc to cha lt c s b p tip cho ti khi nh chui qua li

6 mi thi. Np ba 5 tho m c thay li hoc thay ba.

Hnh 3.8 m t my nghin ba nghin th v trung bnh c li thay ic: l mt kiu my nghin khc cng loi my hnh 3.7, cng np liu tip

tuyn theo chiu quay ca ba, nhng li sng 2 thay i va dng nghin th (l

li sng to) va dng nghin trung bnh khi thay i li sng c c l nh.

a treo ba 1 c bn cht treo ba v cc ba nghin c treo gn nhau sut chiu

rng ca my nghin. S vng quay ca rt trong khong 400- 1000 vng/ph, vn tc

vng ca rto t ti 40m/s v mc nghin bng 10 -15 .

Hnh 3.7. My nghin ba nghin th v Hnh 3.8. My nghin ba nghin

trung bnh c m nghin ph th v trung bnh c li thay i

1.phu np liu; 2.ghi; 3. trc; 4.ba c

5. np my; 6.li sng; 7. m nghin ph 1. a treo ba; 2. li sng

My nghin mn loi ba c np liu chiu trc c gii thiu hnh

3.9. Vt liu em nghin c qua phu 1 c tay quay 8 iu chnh vic np liu

theo nng sut thch hp. Vt liu em nghin c chy thnh lp qua nam chm 2

tch vn st trc khi chy vo khoang nghin. Ba nghin 4 c c thnh dng

su hoc tm cnh, trn hai u cnh i xng c un cong v hai vch trong ca

khoang nghin va thc hin qu trnh p ca u cnh, va thc hin qu trnh

ch xt vt liu nm gia u cnh vi vch 6 trong khoang nghin. Cc vch ny

c to gn tng hiu qu ch xt. Trong khoang nghin cn lp thm tm p 3

v li tho sn phm 5. Trc lp ba nghin c truyn chuyn ng quay t mt


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qua puly 7. Kch thc vt liu em nghin ti 40mm v bt nghin t 0,25mm. Trc

lp ba quay 1800 - 2700 vg/ph, cn cng sut 10 kW. My nghin loi ba c ny

dng thch hp nghin ht, cc loi c, r, cc loi xng v cc ho cht.

Hnh 3.9. My nghin mn loi ba np liu chiu trc

3.1.6. My nghin rng:

Nguyn l: Qu trnh nghin trong my nghin rng cng l do tc dng va p

ca cc rng vi vt liu em nghin nh my nghin ba. Do my ny thngc xp cng loi vi my nghin ba, dng nghin mn hoc rt mn nh my

nghin rng khng c li sng. My nghin rng khng nhng c dng nhiu trong

ngnh lng thc, thc phm m cn c dng c trong ngnh ch bin thc n gia

sc (nghin xng, v s, mui khong v.v...), nghin ho cht v luyn kim. Trong

sn xut thng dng hai loi my nghin rng :

1. Loi c mt roto quay.

2. Loi c hai roto quay.

c hai loi ny gm cu to loi c li sng v khng c li sng.My nghin rng loi mt roto v c li sng: c gii thiu hnh 3.10.

Trn trc quay 5 ca my c lp roto 4, trn roto ny c lp cc dy rng nghin 6

thnh cc vng trn ng tm. Cc rng ny cng xa tm quay th bc rng cng

gim. i din vi roto 4 l a rng c nh 2 lp vi v my 3. Trn a rng c nh

cng lp cc rng 6 thnh cc vng trn ng tm c bc khng i. Cc vng rng


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trn a c nh nm xen gia cc vng rng trn roto quay 4. S rng v s vng rng

thay i tu theo tng loi my vi cc yu cu cng ngh c th khc nhau. Vt liu

em nghin np vo qua ming np liu theo chiu trc, khi ri vo vng rng th nht

c p vng sang vng rng th hai ca a i din, ri li b vng tip sang vng

rng th 3. v.v... qua cc ln va p, vt liu vng t trong ra ngoi v c p nhti khi lt c li sng 1 sang b phn thu hi bt thnh phm.

Hnh 3.10. My nghin rng loi mt roto v c li sng

1. li sng; 2. a rng c nh; 3. v my; 4. roto

5. trc quay; 6. rng nghin

3.1.7.Mt s my nghin trong CN hp .

a. Bm nghin.

Bm nghin thng dng gia cng cc nguyn liu m trong c chanc nhiu nh nghin c chua .

Cu to v nguyn tc lm vic:Hnh 3.11

Trn thn bm bng gang 1 c gn trc quay 2 .

Trn trc quay gn cc li dao 3. Dao 3 c gn sao cho chng to thnh 1

ng xon c. Do phi gn dao n lch vi dao kia mt gc 12 0. Xen k gia cc


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li dao trn trc, ngi ta t cc li dao c nh 4 gn vo thn my. Nguyn liu

qua phu 5 vo my. Do tc dng ca dao quay, nguyn liu c nghin nh v do c

to xon c, nguyn liu nghin c chuyn dn v pha cui c cnh qut 6 y

qua khe h 7 vo bung 8 .

y cnh qut 9 y sn phm nghin theo ng 10 ra ngoi. C 2 cnh qutu gn trn trc quay 2. Kch thc khe h c th iu chnh tu theo yu cu nghin

nh. Khong cch gia dao trn trc v dao c nh l 2,5mm.

Nng sut my khong 800 kg/ h.

S vng quay ca trc 400 vng/ph.

Hnh 3.11 : Bm nghin

b. My ng ha:

Trong cng nghip hp hoc CN ch bin sa, my ng ho c dng

lm ti v nh mn cc thc phm lng nhm tng tiu ho v v mn mng ca sn

phm. Th d khi sn xut nc qu c (nc chui, nc c chua), lm cho nc

qu khng b phn lp sau ny, khi sn xut cc loi hp sp rau qu th cht lng

sn phm c tng ln nhiu.

1. Thn bm .

2. Trc quay3. Li dao4. Li dao c nh

5

12

0

A

B4

5

678

9

1

2

3 10

1

3

4


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Nguyn tc lm vic ca my l dng p lc cao y sn phm i qua cc khe

h rt nh, p sut ca sn phm vo l khong 150 atm v khi ra khi khe nh ch cn

cao hn p sut ngoi tri mt t (2 - 3 atm). Khi thay i p sut mt cch qu t

ngt v tc tng ln nhiu lm cho sn phm b ti nh ra, th d khi chui i qua

thit b ng ho, cc si tht chui c nh i khong 10 ln. Kch thc ca khe hc th iu chnh c t 0,1 0,15 cm, tc chuyn ng ca sn phm qua t

ti 150 -200m/s

My c nng sut 5000 l/h, cng sut in 28 km c gii thiu qua s cu

to v nguyn tc lm vic nh sau :

Hnh 3.12 gii thiu s cu to v nguyn tc lm vic ca my ng ha

nh sau: b phn truyn ng 1 lm quay pittng 2, sn phm i qua van ht 3 v b

nn qua van y 4, khe h 5 ri theo ng y ra ngoi. H thng tay vn 6 v l xo

iu chnh 7 dng iu chnh kch thc khe h 5 gia hm y 8

Hnh 3.12 : My ng ha .

3.2. Cc my ct thi nguyn liu:

3.2.1. Mc ch v phm vi ng dng: ( Khi nim)- Ct l 1 trong nhng phng php lm nh nguyn liu c thc hin bng

li dao, bn dao, dao thanh rng (hay li ca). Trong CNTP thng gp qu trnh

ct thi nguyn liu trong sn xut hp rau qu, hp tht c, CN ch bin cc sn

phm lnh ng, CN sn xut thuc l, CN sn xut ng.

7

8

5

9

42 1

3

1. b phn truyn ng2. pittong3. van ht4. van y5. khe h6. tay vn7. l xo iu chnh8. hm y

6


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* Hiu qu ca qu trnh ct thi: ph thuc trc ht vo b phn dao ct

(ph thuc kiu v dng li dao) v theo c im chuyn ng ca li dao. ng

thi cn ch n mc ch ch yu ca qu trnh ct thi, yu cu v kch thc,

hnh dng v b mt ca ming ct. Qui trnh ct khng li ph liu. V vy my ct

dng trong CNTP phi c nhng yu cu sau:- Cu to dao phi cho php thay i c chiu dy hoc chiu rng ca di sn

phm (m khng cn thay dao)

- Dao phi tch c cc cc sn phm m khng bt x chng ra, khng lm bin

dng r rt sn phm ban u v khng lm nc p trong sn phm chy ra.

- Li dao khi mi mn phi ng u theo tt c chiu di ca n v d mi sc.

- Dao phi gi c cht lng ca sn phm ban u.

* c trng ca qu trnh ct: Qu trnh ct c c trng bng s chuyn

ng tng i ca li dao v sn phm. Trong ng thi xy ra 2 chiu: Trcgiao v song song vi li dao.

Nu gi: vn l tc cp liu (hoc tc tin vo sn phm ca li dao).

: vt l tc trt ca n ln sn phm

n

t

v

v= tg

: Gc trt ; ng vai tr quan trng trong qu trnh ct v ngi ta gi tg l

h s trt (c sch gi l h s ct)

Qua nghin cu nn h s trt cng ln th b mt ct cng nhn v v nt cng t.

Ct c th l cht hoc thi. Nu v t = 0 qu trnh ct s tr thnh cht. V vy,cht l trng hp c bit ca thi .

3.2.2. C cu ca 1 my ct:

C th ch l 1 dao hay gm 1 b dao lp trn 1 hay vi trc song song, sn

phm a vo pha dao bng cch cho n dao cng bc hay t n dao.

Cu to li dao: C th gm c cc loi nh sau:


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- Dao a rng

- Dao a c li nhn.

- Dao hnh cn

- Dao hnh li lim.

- Dao dng bn

- Ca, dao 3 gc, dao xon c.

Hnh 3.13. Hnh dng dao v li ca

a) dao a rng b) dao a c li nhn c) dao hnh cn

d,e) dao hnh li lim f) dao dng bn g) ca dng bng

h) dao ba gc i) dao xon c

3.2.3. Phn loi my ct:

Theo hnh dng ca mt phng phn chia, ngi ta phn bit my ct :

- Theo mt hay vi mt phng thng song song,

- Theo b mt cong

- Theo hnh dng xc nh ca cc vt liu.

- Theo nghin nh hay nghin mn.

3.2.3.1. My ct theo mt hay vi mt phng thng song song:


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Dng dao a, phng, li lim, dng bng chng c truyn chuyn ng

quay, tnh tin hay phc tp. a sn phm vo v ly sn phm ra th dng trng

lc, a liu cng bc hay t ko.

Hnh 3.14. S cc b phn lm vic ca my dng ct theo mt phng

Trn s hnh 3.14-a l s my a a sn phm cng bc nh 1 bng

ti t nm ngang (khi ct tht) hoc nghing (khi ct c). Tc vng ca li dao

tng ng vt, tc cp liu l vn. t sn phm trn mt bng lm vic ca bng tic tin hnh t do hay dng lc t vo tm y lp trn tm bng . Trng hp th

nht vt vn vic ct t lm bin dng sn phm kh ln. Trng hp th 2, lm cc

vu ta gi sn phm c nh th lc vt >> vn, sn phm t bin dng hn nhiu.

C cu ct ny gm c mt, hai hay vi a lp trn mt, hai hay nhiu trc. C

th dng my ct nhiu ca c dao a trong trng hp ct vt rn hay cc sn phm

dng do, cc nh.

Trn s 3.14-b l s b phn lm vic ca my nhiu dao ct sn phm

do. N gm trc 1 c b dao a 2 lp rp vi bc xc nh v trc 3 ca thng quay4, theo b mt ct ca thng c rnh vng m bo ct t sn phm. Thng quay 4

dng cp liu. Tc vng ca n tng ng vi tc cp liu vn, cn tc

vng ca trc 1 tc l tc trt ca li dao v t. T l : vt : vn = 3 - 5.

Chiu dy ln nht ca cc em ct quyt nh chiu rng ca khe . Nng

sut ca c cu tnh bng :


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Q = .s.l.vn m3/s

Trong : : H s s dng nng sut ln nht c th t c

s : Chiu rng khe, m.

l : Chiu di ca khe sn phm i qua 1 cch t do m

vn : n dao, m/s

Trn hnh 3.14-c l c cu lm vic vi cc dao a lp trn mt trc, v sn

.phm t n dao qua vng lm vic. T n dao c m bo bng ma st sinh ra gia

sn phm v cc dao a. y, momen lc ct phi nh hn momen lc ma st xut

hin trn b mt tip xc ca dao vi sn phm.

Trn hnh 3.14- e l s cu to ca c cu lm vic c dao a lp trn 2 trc

song song v sn phm t n dao qua vng lm vic. T n dao c m bo bng

ma st sinh ra gia sn phm v dao lp i xng i vi ng trc ca rnh np sn

phm. Tc cho nguyn liu n dao s nh nht thi im n dao trung bnh khi

ngp ht na th nht ca a v ln nht khi sn phm cha y hon ton tit din

ca rnh ni t a.

Trn hnh 3.14-.f l s cc b phn lm vic ca my ct c ca dng bng.

y bng chuyn ng vi tc vt ct sn phm a vo bng ti vi vn tc vn.

Bnh ai ch ng, t pha di, cn bnh ko cng th pha trn. Trn my c

th lp mt hay mt s li ca lm vic ng thi hoc ni tip nhau.

ct x phng, keo xng, trng luc v nhng sn phm tng t cng loi

c tr lc ct nh, ngi ta dng chi tit ct l nhng dy ko cng 1 (hnh 3.15) buc

cht trn khung 2. i khi khung c truyn chuyn ng dao ng thnh thi (ct

trt).

Hnh 3.15. S my ct x phng v cc sn phm nh trng, keo xng


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3.2.3.2. My ct sn phm theo b mt cong:

Gm c cc loi dao hnh cn, hnh cu, xon c hay loi dao t hp, m bo

khi a sn phm vo th to hnh phi phn chia theo ng cong b mt.

Trn s hnh 3.16-a l s cu to v lm vic ca c cu dao hnh cn,

m bo chia phn sn phm theo b mt hnh tr. y tc vng ca a tngng vi vt, cn tc cp nguyn liu cho a hay tc n dao vo sn phm tng

ng vi vn. ct c cht lng theo t l ca chng nm trong gii hn 30-50

Trn hnh 3.16-b l s cu to ca c cu ct vi dao hnh cu c truyn

chuyn ng quay xung quanh trc nm ngang XX vi tc vng v t = R v a sn

phm vo hay quay dao xung quanh trc thng ng vi tc trung bnh vn = R1. V

dao hnh cu nn h s trt khi ct KC = : 1, trong v 1 l cc tc gc

quay tng ng.

Trn hnh 3.16- c l s nguyn l v cu to v s lm vic ca dao xon c.Cu to ca dao nh th m bo ly c phoi mng khi tc cp liu khng ln.T

l gia tc vng ca dao vt v tc a sn phm vo vn l K= 40-50. Chiu dy

phoi ct ra l 0,3-0,6 mm

Trn hnh 3.16- d l s dao nhiu mt dng ct c ci ng trc khi

cho vo thit b khuch tn. Cu to ca dao nh vy c phoi dng hnh mng

bn, trnh s ng tng ca nguyn liu khi cht y trong thit b khuch tn.

Hnh 3.16. S cc c cu ct theo b mt cong


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3.2.3.3. My phn chia sn phm ra thnh tng ming c hnh dng v

kch thc xc nh:

Dng ct sn phm ban u ra thnh tng mu nh di dng lt, tm,

khoanh, cc nh, thanh, si, ming lp phng.

- Trn hnh 3.17- a,b l s nguyn l v cu to v s lm vic ca ccmy ct thnh tng cc nh hay thnh tng lt. B phn lm vic gm bung 1

cp nguyn liu vo, c hnh dng nh 1 ci chm, m bo p u sn phm v

hng sn phm vo b phn dao ct. B phn dao ct gm a 2 nm ngang (a) hay

thng ng (b) c gn dao 3. my (a) c dao hnh rng lc v phng, cn my (b)

th dao phng. Sn phm sau khi ct c ly ra qua ca (4) nh trng lng bn thn

ca n. Trong my (a) dao lp vung gc vi hng chuyn ng v thc hin cht

my (b) th dao t di 1 gc i vi bn knh v hnh thnh qu trnh thi.

Trn hnh 3.17 c l s c cu a ct sn phm ra thnh si. y trnmt a dp hnh cc chi tit ct dao hnh tri xoan, cn l th hnh trn m bo ct

ra c hnh si

Hnh 3.17. S cc b phn lm vic ca cc my dng ct thnh lt,

khoanh, thanh v thnh si

Hnh 3.18 th hin s cc my dng ct thnh tm, thnh cc nh v

thnh ming lp phng trong :Cc c cu lm vic ct sn phm ra thnh lt (tm): S hnh

3.18.a,b.Trong trng hp th nht a), vic ct tin hnh bng dao tm 1. Dao ny

truyn chuyn ng dao ng. Trng hp b, vic ct lt tin hnh bng dao a 1. Sn

phm c a vo nh cp trc 2, 3 lp trn gi di ng, cn trc quay 3 th lp

trn gi c nh.


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Cc c cu lm vic dng ct sn phm ra thnh ming lp phng hay

hnh hp ( hnh 3.18- c v d ). S 3.18-c gm 2 b dao tm 1 v 2 v dao hnh li

lim 3. S 3.18.d gm 2 b dao a 1,2 v mt dao hnh li lim 3. Kch thc ca

ming lp phng c xc nh bng khong cch gia 2 b dao th nht v theo

vng quay ca dao hnh li limNng sut ca cc c cu phn chia sn phm ra thnh cc c hnh dng nht

nh.

Q = f0 vsp (m3/s)

Trong :

f0 : Din tch tit din sng ca lp sn phm chuyn ng qua c cu ct. m2

vsp : Tc cp sn phm (m/s)

Hnh 3.18. S cc my dng ct thnh tm, thnh cc nh v thnhming lp phng

3.2.3.4. C cu nghin nh v nghin mn:

c dng khi yu cu nghin sn phm tng i nh v mn( hnh 2.23)


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Hnh 3.19. S cc my ct dng nghin mn

Trn hnh 3.19-a l s lm vic ca my xay tht hoc c dng nghin

trung bnh v nh. B phn lm vic gm c cu cp sn phm l mt vt ti 1 vi

bc thay i v v tr 2. C cu ct gm cc li dao quay 3 lp tng cp vi cc

li 4, kch thc ca l li gim theo hng chuyn ng ca sn phm. pha ca

ra ca c cu c t vng khu 5, khi vn vo ai c 6 th vng khu ny s xit cht

dao trn li m bo ct c sn phm. Vt ti 1 quay bn trong v tr to nn 1 lc

p y sn phm v pha c cu ct v n sn phm i qua l li v truyn chuyn

ng cho dao quay.

Trn hnh 3.19-b l s b phn lm vic ca my bm dng nghin nh

hng lot sn phm thc phm nh tht, c, rau, m....My lm vic gin on, sn

phm cn nghin c a vo chu quay 1, y kn mt phn bi np 2 ng m

theo kiu bn l. Trong vng lm vic c lp trc 3, trn trc gn dao 4.

Trn hnh 3.19-c l s nguyn l cu to ca my bm quay c thng 1 thay

cho chu quay xung quanh trc nm ngang vi tc ln. Qu trnh nghin c thchin nh mt b dao hnh li lim 2, lp trn trc nm ngang 3.

3.2.4. Mt s my ct thc t:

3.2.4.1. My thi thn l thc vt: My thi rau c rm PCB-3,5


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Hnh 3. 20.My thi rau c rm PCB-3,5

1. Khung 2. Dy chuyn 3. cn ng m

4,5. trc cun cung cp di v trn. 6. l xo nn 7. trng thi

8. bnh 9. mng 10. tm k thi

Hnh 3.21. cc c cu chuyn v cung cp vt thi

a) Cc trc cung cp( mt ct): 1. Tm k thi 2. l xo 3. v


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4. trc cun trn 5. Trc cun di 6. Xch 7. trc dy chuyn 8. cn ng m

b) Dy chuyn (mt bng): 1. trc ch ng 2. xch ca dy chuyn 3. thanh

kim loi 4. tm g 5. thanh bn 6. inh c cng 7. Trc ph ng

Hnh 3.22. Trng thi1. bnh 2. bnh rng nh thay th 3. thn gi 4.dao 5. b phn ly hp

6. khp ch thp 7. trc 8. bnh rng ln thay th 9. puly

3.2.4.2. My thi c qu:

Hnh 3.23. My thi c qu kiu a nm ngang KPM

1. a 2. Dao 3.Cc hp 4.trc truyn thng ng


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Hnh 3.24. My thi c qu kiu thng ng PKP-2,0

1. a 2.Dao 3. Thng cp liu 4. Mng thot

:


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CHNG 4. CC MY P

4.1. Khi nim:

p l qu trnh tc ng lc c hc ln vt liu lm vt liu b bin dng nhmmc ch:.

- Phn chia pha lng rn trong vt liu.

- nh hnh - Bin dng vt liu.

Phm vi s dng:

Sn xut ng, sn xut nc qu, sn xut du thc vt, tinh du.

Sn xut u ph, pho mt, b .

Ch bin bnh m, m si, bnh bch qui.

To hnh m si, bnh qui, p ng thnh vin, p cc sn phm kh: Bnh

rau, lng kh, vin canh

p cc loi bnh men, cc bnh thc n gia sc.

p cc vin thuc, cc loi ko.

Chun b cho cc qu trnh ch bin tip theo .

Cc yu t nh hng n qu trnh p:

+ Tnh cht vt liu

+ p lc p

+ Vn tc my p

+ Thit b p

+ Thao tc: u ca vt liu vo p

+ Vn cung cp nng lng.

4.2. Phn loi my p: C hai nhm my p l nhm my p tch pha lng ra khi

pha rnv nhm my p to hnh sn phm

4.2.1. My p tch pha lng ra khi pha rn4.2.1.1. My p trc vt: My p trc vt l loi my p lm vic lin tc, c

th s dng cho nhiu loi nguyn liu khc nhau. B phn lm vic chnh ca my l

trc vt c bc vt nh dn hay ng knh trc ln dn quay trong xi lanh nm

ngang. Nguyn liu p khi di chuyn theo trc p chu p sut tng dn. S p xy ra

do khe h gia xi lanh v bc vt gim dn.


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My p kiu trc vt thng dng trong cc nh my tinh du, nh my hp

(p nc c chua v..v)

Hnh 4.1. MY P TRC VT

Trc vt 1 t trong xi lanh c c l 2 c nh. Trc quay 250 vng/pht.

Nguyn liu vo phu 3. Nc p chy qua l trn xi lanh vo mng 4 ra ngoi. B p

qua ca 5 ra theo mng 6. Kch thc ca tho b 5 c th iu chnh ty theo tca b i ra bng cch tnh tin trc vt v pha trc hay lui li v pha sau. Ca nh

nc p chy ra nhiu hn nhng cht lng km hn. Lc mi cho my chy nn

m to ca sau gim dn. Nng sut ca my p trc vt loi ln c th t c

khong 5 tn/ pht. p sut to ra khong 8-10kg/cm2.

Nng sut my p trc vt

Q = 3600 F0 .v0.. ( kg/ h)

F0 : Din tch ct ngang ca lp nguyn liu trong xi lanh ( m2)

F0 =4

)( 2120 dd

d0 : ng knh trong ca xi lanh (ch ca vo ) m

d1 : ng knh c trc vt ( u) m

v0 : Tc nguyn liu chy dc theo trc vt m/s

3 1 2

64

55

4 6

32

My p c ng knhtrc vt ln dn

Xi lanh hnh tr

My p c ng knhtrc vt nh dn

Xi lanh hnh nn

1


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v0 =60

ns

n : S vng quay ca trc vt (vng/pht)

s : Bc vt ( u ) (m)

: H s cha y ca nguyn liu = 0,6 0,7 .

: Khi lng ring nguyn liu (kg/ m3)

Nhc im ca my p trc vt: Ch xt mnh trong qu trnh p, do lm

cho nc ngt (hoc du) b vn c.

4.2.1.2. My p thy lc:

L loi my thng c dng trong cc nh my ch bin thc phm nh sn

xut ru vang. N gm bm A c nhiu pittng tr, thng cha B, b phn phi C

v my p D, sn phm p c np vo bung 14.

Hnh 4.2. S thit b p thy lc ( p ru vang)

Nguyn tc lm vic:


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Khi bt u lm vic, a tay gt 18 vo v tr II v cho bm chy.

Khi pittng tr 2 chuyn sang bn tri nng van ht 3 v cht lng lm vic t

thng cha B dng ln ng 4 v np y xi lanh ca bm. Khi pit tng tr chuyn

ng ngc li th van 3 ng, van 1 m. Cht lng lm vic theo ng 10, i vo b

phn phi C. Qua van nng 6, cht lng chy vo xi lanh lm vic ca my p. Di

p sut ca cht lng lm vic, pittng 15 nng bung 14 c sn phm p v pha u

p 13. Trong bung to ra p sut mi mt, nn 1 phn cht lng ca sn phm p

c tch ra qua b mt khoan l ca bung p .

p sut ca pittng truyn qua sn phm n thanh ging 11 v thanh ngang

12. Tu theo vic tch mt phn cht lng m p sut tng ln trong xilanh lm vic

ca my p v trong cc ng ng dn. Trong khi th tch ca sn phm p gim

i, nn tc nng ca tr trn cng phi gim. Do phi thay i vic bm cht

lng lm vic: Cht lng t xi lanh ca bm theo ng 9 i vo di pittng 7 v p

lc n n mt p sut nht nh, pittng nng ln trn p l xo 5 v m van 8. Qua

van , cht lng chy v pha van ht 3 ca bm, nh lng cht lng i vo xi

lanh lm vic ca my p gim i.

Khi p xong th tt bm v chuyn tay gt 18 v v tr I, khi van 6 ng li,

van 17 m ra v cht lng lm vic t xi lanh 16 chy vo phn bn phi ca thng B.

Tr trn 15 v bung p 14 c h xung di v b c tho ra. thng B c t

li 10, lc cht lng lm vic trc, khi vo xi lanh ca bm .

4.2.1.3. My p trc:

1. Cu to my p:

Mt b my p gm cc b phn chnh:

- Gi my.

- Cc trc p: Trc nh, trc trc, trc sau.

- B gi trc v b iu chnh v tr lp trc.

- B phn nn trc nh.

- Tm dn ma (lc y v cc lc khc)2. Trc p:

Gm c li trc bng thp, 1 u gn 1 bnh xe rng cao chn truyn chuynng, lng cht trong o trc bng gang c bit. Thp lm li trc c thnh phnNi = 3-4% ; Cr = 0,5 - 1% ; C = 0,2 0,45%. Hai c trc trn nhn bng, ng knhbng 1/2 ng knh trc p. . hai u ao truc co vanh chn nc ma khoi bn vao


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c truc. Hnh dang va v tr lp cua vanh o trn truc nh va hai truc trc co khacnhau

Gi my c nhiu kiu: kiu nh thng (hnh 2.31), kiu nh nghing v kiucn nn cong (hnh 2.32)

Hnh 4.3: My p kiu nh thng Hnh 4.4: My p kiu cn cong.(kiu Fives Lille- Cail C46).

3. B phn nn trc nh ( p lc trc nh) .

Trong qu trnh p, p lc trc nh ng vai tr quyt nh. N ph v t bo

ma, gii phng nc ma ra khi t bo.

to ra p lc ln trc nh, c th s dng cc thit b :

- Thit b tng p l xo

- Thit b tng p du

- Thit b tng p kh nn.

Nhc im ca thit b tng p l xo l lc tc dng ln trc nh khng u

nn hin nay t dng.


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Ta thy p sut du l F =22

4

4

d

p

d

p

=

Theo nguyn l Pascan, p sut ny chnh l p sut trong hp du. Do vy p

lc tc dng ln c trc s l :4

.2D

F

Lc tc dng ln trc nh l P = 2 . pd

DD

d

p..2

4.

42

22

2=

So snh lc tc dng ln trc nh vi khi lng gang bn A

2

2

2

2

2.2d

D

p

P

d

D

p

P==

u: To c p lc ln trc nh. p lc ny khng thay i khi lp ma

vo dy mng khc nhau.

Nhc: Chim nhiu din tch .

Lm vic nng n, mc ln.

5. Thit b, tng p bng kh nn:

Nguyn l ging thit b tng p bng du nhng p sut cao, y c to

ra bng kh nn.

4.2.1.4. My p dng kh nn:

Trong my p ny lc tc dng ln nguyn liu l khng kh nn. My ny cdng nhiu trong dy chuyn sn xut nc qu trong cho cc nguyn liu khng

cng nh da, cam, qut (hoc nho), phng php p ny rt tt v qu trnh p khng

ph v nhng c cu cng ca nguyn liu v, cung, x, l nhng cht khng c li

cho thnh phn ca nc qu.

My lm vic gin on, chu k p 2,5 gi (cc thao tc ph u c c kh

ho)

Cu to v nguyn tc lm vic ca my p dng kh nn

Thng p 1 lm bng kim loi khng r, tm dy 1mm, trn c c l1,2 x 20mm. Bn ngoi bc cc tm kim loi chu lc. Hai u thng p 2 bng gang,

bn trong lt kim loi khng r. Dc thng p c ca nguyn liu vo p, c th

ng cht nh 1 cnh ca c vt vn. Bn trong thng p l thng cao su 3


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Hnh 4.8. S nguyn l lm vic ca my p dng kh nn

1. Thng p . 2. u thng p.

3. Thng cao su. 4. ng dn khng kh nn.

5. Trc rng 6. trc.

. Khng kh nn t my nn kh i theo ng 4 vo trc rng 5 qua cc l c

trn trc vo trong thng cao su (trn hnh v thng cao su trng thi khng p).

Di tc dng ca khng kh nn thng cao su b cng ln to mt p sut cn thit,

tc dng ln nguyn liu p nc qu. Lp nguyn liu p nm gia thng p v

thng cao su. Nc p qua l trn thng p ra ngoi mng hng chy i. B cn li

trong thng p, sau mi ln p m ca trn thng v cho thng quay, b s t ri ra

ngoi mng c trc vt y i.

Mi my p phi dng ti 3 ng c in quay thng p, trc vt v cho my

nn kh. Vn tc thng p 20 vng/pht. Nng sut my 1,5 tn nguyn liu/ gi.

My p ny lp trn khung khng cn b xy kch thc 5180 x 2510 x 2290mm.

Qu trnh p: Thng khng quay cho nguyn liu vo t t cho ti khi y, ng

ca li cho thng quay 5 pht khng cho khng kh vo. Khi nguyn liu c

phn b u trn mt thng. Bt u cho khng kh vo thng cao su. Cho t t 5 -

10 pht cho t n p sut 3 3,5 atm. Li x kh ra cho thng quay o nguyn

liu. Li cho khng kh nn vo vi p sut cao hn v gi thi gian lu hn. Lm

nh vy 3 ln v p sut khng kh nn ln cui cng trong thng cao su phi t 6

atm.

2

3 1

6

4

5


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4.2.2. My p to hnh:

4.2.2.1. My p trc ln (My p nn)

Dng trong sn xut m ng.

Hnh 4.9 : Nguyn l lm vic ca my p nnMy p trc ln lm vic lin tc, gm c b phn nn (2 trc ln) v b phn

to hnh (khun c ). Hai trc ln quay ngc chiu nhau to nn p sut y bt

nho v khun c.

Khun c l cc a kim loi c gia cng l c hoa vn

4.2.2.2. My p cn:

a. Nhng cc bt nho m chuyn ng nh bng ti vn chuyn 1 v tc dng

ln mng c nh 2 (hnh 2.38.a). Khi cc bt nho i dc theo mng c tit din nh

dn th n c gi cht to nn c cu ng nht v trn.b. Qu trnh dt mng nhng cc bt nho m u xy ra khi n chuyn ng

dc theo k h nh dn to nn bi bng ti vn chuyn 1 v thnh c nh 2 hoc

bng ti v tn khc 3, chuyn ng v pha ngc li.Lc ny cc bt nho quay

xung quanh trc ca n, chuyn di ra khi khe h v dn dn c to thnh hnh

tr ( hnh 2.38b).


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c. Khi dt bt nho m trng s thc hin 1 s khu. u tin nhng cc bt

nho i qua gia i trc 1, quay ngc chiu nhau v cn mng thnh bnh. Sau

nh trc c rnh 2 c cun li thnh cun xon c. Cun c a ra bi thng

quay 3, v c cn gia thng v b mt v my c nh 4 v sau chuyn sang

bng ti 5, kt qu n t ko di ra n kch thc cn thit (hnh 2.38c) .

Hnh 4.10 : Nguyn l lm vic ca my p cn.

4.2.2.3. My dp p:Dng trong CN bnh ko.

Hnh 4.11. S my dp p to hnh bnh quiB phn to hnh( khun c 1 ca my p (hnh 2.39) c gia cng thnh

hnh hoa vn phong ph. B phn to hnh thc hin chuyn ng qua li, a khi

bt nho c cn 2 nm trn bng ti 3 v p xung. p sut dp gn 0,3-0,5

MN/m2( 3-5 kg/cm2)

1

2

3


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4.2.2.4. My p ng bnh :

B phn ch yu ca my p c khun c kiu ng l cc a hoc ci bnh

quay chm.

a c nhng l t cc khun c. Vt liu m t b phn np liu chovo cc khun ng bnh. y khun l cc bn di ng ln xung.

Qu trnh ng bnh c th theo di s hnh 2.40. To v tr I, bn 2

thp nht. Sau khun c 1 cht y sn phm t 3 (v tr II), tip n p nguyn

liu bi bn ( giai on ny trn khun c c t tm 4 v tr III) v cui cng

bn y thnh phm ng bnh v nng cao hn mt bn khong 0,5mm.

Trong 1 vng, bn s ngng li 4 ln vi thi gian 11,5 giy, c 4 khun c,

lm vic vi v = 8 vng/ pht, to 32 bnh/ pht. p sut p gn 150 - 200 kg/ cm 2 .

Hnh 4.12. S lm vic ca my p c khun c kiu ng

1. Khun c 2. Bn

3. sn phm 4. Tm kim loi


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CHNG 5: CC MY NH LNG

1. MC CH V PHM VI NG DNG

Trong cc nh my thc phm, qu trnh nh lng nguyn liu, nh lng vt

liu b sung v thnh phm c ngha ln m bo nng sut v hiu sut sn xut

cng nh mi ch tiu cht lng ca sn phm.i tng nh lng rt a dng v phong ph nh: dng ri, lng t nht, lng

nht, m c, do, nho, qunh. Do , ty theo cu to v tnh cht ca sn phm

cn nh lng m c cc phng php v cc thit b nh lng khc nhau.

Cc my nh lng thng c lp ngay di boong ke cha, t trc cc

my v thit b ch bin hoc cc my trn v.v...

2. PHN LOI

2.1.Theo nguyn tc nh lng:

- My nh lng theo th tch: Cu to n gin, d s dng nhng mc chnh xc thp

- My nh lng theo trng lng: Kt cu phc tp, gi thnh cao nhng

mc chnh xc cao

Phng php nh lng th tch c sai s t 2-3% nn ch p dng khi o

lng s b. Phng php nh lng theo khi lng c sai s nh lng thp

khong 0,1% nn c p dng khi cn o lng chnh xc cc cu t ca hn hp.

2.2. Theo phng thc lm vic.

- My nh lng lin tc

- My nh lng gin on (tng m)

2.3. Theo tnh cht vt liu.

- My nh lng vt liu ri

- My nh lng vt liu do

- My nh lng vt liu lng.

3. CC MY NH LNG VT LIU RI.

nh lng vt liu ri hay l cc sn phm ht, ngi ta dng cc my nh

lng th tch v trng lng, nh lng lin tc v tng phn. Phng php nh

lng theo th tch c sai s ln hn nhng kt cu my n gin hn, sai s nmtrong gii hn cho php nn vn c s dng rng ri trong nhiu dy chuyn sn

xut.

Nhng my nh lng cp liu lin tc thng gp l loi thng, a, vt ti, bng

ti, my lc, pittng, rung lc v dao ng cng nh loi trng lng lm vic t ng

v na t ng.


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3.1. Thng nh lng : (My nh lng kiu tang)

3.1.1. c im v phm vi ng dng:

- My nh lng th tch lm vic lin tc

- nh lng cc sn phm dng ri, dng ht, bt v..v

3.1.2. Phn loi:

- Kiu thng hnh tr hay thng c nhiu cnh (hnh 5.1a v 5.1 b): iu chnhdng sn phm nh lc ma st v lc bm dnh vi b mt thng.

- Kiu hnh qut: loi hc (hnh 5.1c) v loi cnh ( hnh 5.1d): cc loi thng ny

th loi thng tr nhn v c nhng np gn nh dng cho sn phm bt v ht nh.

Nhng thng mi cnh dng cho sn phm dng cc nh v cc trung bnh.

Hnh 5.1. Cc thng nh lng

a) Thng nh lng hnh tr b) Thng nh lng c cnh

c) Thng nh lng c hc d) thng nh lng c cnh

1. Trc thng 2. Thng 3. L tho 4. Ci no co vt liu d

trong cc ngn 5. Ngn 6. Thng cha liu 7. Trc no

Tc vng ca thng t 0,025 n 1m/s. Nng sut ca thng c th iu

chnh bng tm chn thay i chiu dy ca lp sn phm i vo, hoc thay i s

vng quay ca tang.

Nng sut thng cp liu kiu tang trn (Hnh 6.1a ) c tnh theo cng thc :

Q = 3600 F v k , kg/h

Trong : F : Din tch tit din ca l, m2.

v : Tc trung bnh ca sn phm chy qua l, (m/s )

(Thng ly bng vn tc vng ca tang nh lng v = 0,025 - 1 m/s)k : H s cha y ca ca xung liu, ph thuc khi lng ring ca ht .

: Trng lng ring ca sn phm kg/ m3

3.2. a nh lng :



- Dng cp v nh lng vt liu dng ht nh v dng bt kh.


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- m bo cp liu chnh xc khi nng sut tng i ln.

3.2.2. S kt cu:

a quay mm nh lng (hnh 5.2a) l mt

a quay nm ngang 1, sn phm trn a c

iu chnh bng ng tip liu di ng 3 ph bn

ngoi ng tho ca boong ke.ng c in lm quay trc thng ng 4

qua c cu truyn ng.

Hnh 5.2a. S kt cu mm hay a nh lng

3.2.3.Cu to v nguyn tc lm vic

Cu to:

1. a cha liu2. Trc3. ai thang4. Hp gim tc5. Bnh rng thng6. Hp cp liu7. ng c nh8. ng di ng9. Tm gt10.ai c11.Tay quay12.Cp bnh rng nn13.Bnh rng vng14.Bnh rng15.Cnh o

Hnh 5.2b. My nh lng kiu aNguyn tc lm vic:

a 1 lp cng trn trc 2 nhn chuyn ng quay t mt qua ai thang 3, hp

gim tc 4 v cp bnh rng thng 5. Liu t hp cha liu 6 chy qua 2 cnh o 15

gn trn trc 2 ( chng dnh bt) ri xung a 1. iu chnh lng liu trn a

1, dng h thng ng chn liu 7 v 8. ng 7 pha trong lp c nh, mt ngoi ng c

tin ren. ng 8 lng ngoi ng 7, u pha trn hn vi ai c 10 - n ren trn ng 7.


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ai c 10 hn vi bnh rng vng 13 n khp vi bnh rng 14. Khi tay quay 11 quay

truyn chuyn ng qua cp bnh rng nn 12, cp bnh rng 14 v 13 lm ai c 10

quay n ren vi ng 7 c nh. Do cng lm ng 8 cng ai 13 va quay va tnh

tin dc trc (ln hoc xung) lm thay i lng liu trn a 1. Dng gt 9 (cng

iu chnh c v tr cao thp) gt liu trn a 1 xung ng tho liu.

C 2 kh nng iu chnh nng sut :- Thay i vng quay ca trc 2 mang a 1.

- Dch chuyn v tr ng 8 bng tay quay 11.

3.2.4. Nng sut ca a nh lng :

Nng sut ca a nh lng c tnh theo cng thc:

Q = 60

+

00

2

3

tg

hR

tg

nh, kg/h

Trong :

: Khi lng ring ca ht hoc bt kg/m3

.h : Chiu cao nng ng tip liu 8 so vi a (m)

n: S vng quay ca a, vng/pht

R : Bn knh ng tip liu 8, m.

: Gc nghing t nhin ca khi vt liu khi chuyn ng,

3.3. Vt nh lng



- Vt nh lng dng cp v nh lng sn phm dng ht, cc nh v dng

bt trong nhng trng hp b qua hin tng nghin nt.

- My c th nh lng v tr t nm ngang hay nm nghing mt gc no .

3.3.2. Cu to vt nh lng

Hnh 5.3. Vt nh lng


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3.3.3. Nng sut ca vt nh lng:

Nng sut ca vt nh lng c xc nh theo cng thc :

Q = 47 D2 SK n ( kg/h)

Trong :

D : ng knh vt xon , m

S : Bc vt, m Thng thng : S = (0,8 - 1,0) DK : H s y, K= 0,8 - 1,0

n : S vng quay ca vt xon trong 1 pht. i vi sn phm linh ng

n = 40 - 80 v/ ph, t linh ng hn th n = 20 - 40 v/ph.

: Khi lng ring ca sn phm (kg/m3)

trnh vt liu tch t trong vt nh lng cn phi m bo t l:

D (4-5) DC (mm)

Trong : DC : Kch thc ln nht ca cc sn phm .

3.4. Bng ti nh lng3.4.1. c im v phm vi ng dng:

- My nh lng lm vic lin tc

- Dng cp v nh lng vt liu cc nh cng nh vt liu m dnh kt. Vi

vt liu m, dnh, dng thanh gt lm sch b phn chu ti v bng vi bng tm cao

su

- Bng ti nh lng c th t nm ngang hay nm nghing.

3.4.2. Phn loi:

- Bng ti nh lng theo th tch.

- Bng ti nh lng theo trng lng

3.4.3. Bng ti nh lng theo th tch

Hnh 5.4. Bng ti nh lng theo th tch

1. Khung 2. tang dn 3. tang cng ( tang ko) 4. Bng 5. ng c in

6. Hp gim tc dn ng 7. im ta ca thng cha liu 8. Phu cha


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9. Tm chn iu chnh 10. C cu ko cng

Nhnh bng pha trn bng nhng con ln nh lng. Dc theo bng c t

thanh chn to thnh mng nh dn sn phm cp liu. Vt liu t thng cha liu

c cp vo bng mt cch u n v c th iu chnh theo chiu cao ca tm

chn. Tc ca bng ly t 0,1 - 0,5m/s.

3.4.4. Bng ti nh lng theo khi lng- Bng ti nh lng theo khi lng ta trn gi bn l

Hnh 5.5. Bng ti nh lng theo khi lng

Trn hnh 5.5 cho ta s nguyn tc ca bng ti nh lng theo khi lng;c cu ny lp trn khung, ta trn gi bn l. Sn phm cp bng bng ti c

cn bng i trng; dch chuyn i trng c th iu chnh c nng sut trong gii

hn 1/3. Khi thay i nghing ca khung my nh lng th do thay i trng

lng sn phm nn h thng n by t ng thay i v tr iu chnh tm chn v

tit din l ra ca thng cha liu.

- Bng ti nh lng theo khi lng iu chnh bng in

Hnh 5.6a. Bngti nh lng theo khi lng iu chnh bng in1. Bng ti 2. im ta 3. ng c in 4. Cnh tay n 5. Tay n

6. C cu cp liu dao ng in 7. i trng 8. Cng tc in

Bng ti nh lng theo trng lng c th t ng ho nh thit b in kh

nn thy lc.

Trn hnh 5.6a cho bit s thit b in iu chnh qu trnh lm vic ca

my nh lng - Bng ti 1 lc trn im ta 2 c dn ng bng ng c in 3.


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Tin hnh cn bng nh c cu cnh tay n trng lng 4 vi tay n 5 v i trng

7. Vt liu c a vo bng c cu cp liu dao ng in 6. tay n 5 c h

thng cng tc in 8 qua mt thit b c bit lm thay i ch lm vic ca b

rung, nh hng n vic cung cp vt liu, sao cho khi phc c s cn bng ca

h trng lng.

Trn hnh 5.6b l s mt kiu bng ti nh lng iu chnh bng inkhc. S iu chnh c thc hin bng cch thay i c cu cp liu 7. khi thay

i trng lng ca bng ti 1, c cu trng lng 2,3 v 4 lm thay i v tr ca h

thng ct in 5. Nh iu khin bng in m thay i c t s truyn ca b bin

tc 6, lm chuyn ng my cp liu 7

Hnh 5.6b. Bng ti nh lng theo trng lng iu chnhbng in thay i tc cp liu

1. Bng ti 2,3,4. C cu trng lng 5. H thng ct in

6. B bin tc 7. My cp liu

3.5 CC MY NH LNG THEO TRNG LNG

3.5.1. c im:

- My nh lng trng lng loi tng phn mt gm cc b phn:

. B phn cp liu cp sn phm vo nh lng.

. Thng cha cn.

. B phn iu khin t ng my nh lng

- thng cha phi c hnh dng nh th no n tip nhn c hon ton vt

liu dng ri da vo v tho liu ra ht sau khi xc nh trng lng

Cc my nh lng theo trng lng c cc loi sau:


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3.5.2. My nh lng bt:

Hnh 5.7. My nh lng bn t ng dng cho bt

1. Phu cha bt cn cn 6. Lng tr

2.Vt ti bt 7,8. Cnh tay n

3.ng c in 9. i trng

4.B gim tc 10. B phn ng ct in

5.Thng nh lng

Trn hnh 5.7 l my nh lng trng lng bn t ng dng cho bt, chuyn

bt t thng cha 1 bng vt ti 2, vt ti ny c truyn chuyn ng quay t ng

c in 3 qua b gim tc 4. Bt i vo trong thng cha nh lng 5, phn cui ca

thng cha c gn lng tr 6 ta trn cc tay n ca c cu trng lng 7 v 8, i

trng 9 v b phn ng ct in 10 ca ng c vt ti cp liu v nh ch vic cp

bt. Tin hnh ng in li cho vt ti cp liu nt n tay 11.

iu khin t ng my nh lng theo trng lng tng phn, ngi ta

dng b phn c in hay in v kh nn.

3.5.3. My nh lng iu khin bng kh nn hay thy lc:

Trn hnh 5.8 cho bit cc b phn iu chnh my cp liu nh lng trng

lng lm vic lin tc. My nh lng trng lng l tang c nhiu hc 1, c cnbng trn n by 2 bng i trng 3 (di ng chnh li c cu nh lng) v 4.

Khi thay i trng lng, tang 1 truyn ng bng n by lm thay i v tr

ca van 5, iu chnh vic cp khng kh nn hay du, lm thay i v tr pt tng ca

ng c tr ng 6 v co 7, thay i lng vt liu do a cp liu 8 cung cp.

i vi cc my nh lng trng lng th b phn ng in n gin v

thun tin hn c l cng tc thy ngn; chng c t trn nhng chi tit tng ng


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ca c cu nh lng trng lng (n by hay thanh lc) m v tr ca n thay i

trong qu trnh cn. Nhng trang b nh lng ng bao t ng thng gp c cu

to khc nhau ph thuc vo tnh cht c l ca sn phm cn (bt ng, ht go,

ch, ko, m ng v cc sn phm thc phm khc).

Hnh 5.8. My nh lng iu chnh bng kh nn hay thy lc

3.5.4. My nh lng bng t bo quang in Khi nh lng ng bao c th dng my nh lng cn mt ln v cc my

nh lng cn nhiu ln. Khi cn mt ln th thc hin nh lng trng lng mt

phn sn phm sau mt ln nhn.

Trong cc my nh lng cn nhiu ln c phn trng lng bit th

tin hnh cn mt vi ln lin tc; iu cho php tng s ln cn trong mt n v

thi gian m khng gim mc chnh xc ca vic nh lng.

Di y l s nguyn l s iu khin t ng my nh lng bng t bo

quang in (hnh 5.9):

Bao b rng a ln trn bn quay v a v pha b phn cp liu dao ng 1,2.

Hp bao b i vo mt trong cc a cn ca n cn, trn a cn khc c t sn mu

trng lng; lp mt mn chn nh trn u n cn ny, khi t n trng lng cn

bng th tm chn che ngun nh sng tc dng ln t bo quang in. trong khi

th rle quang in b tiu hao, tc dng n cc b phn tha hnh ca thit b t

ng, lm nh ch vic cp sn phm vo trong bao b. ng thi c cu bn quay


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lm vic, y bao b y ra v t ln bao b rng khc. Sau b phn cp liu

bng dao ng li t ng lm vic v lm y bao b mi.

Hnh 5.9. My nh lng trng lng nh t bo quang in

1. Phu np liu 6. l chn

2. B rung 7. Mu trng lng

3. n chiu sng 8. bn cn

4. ng dn lung sng 9. Bao b np y

5.T bo quang in 10. Bao b rng

11. Rle quang in

4. CC MY NH LNG DNG CHO SN PHM DNG BT NHO

4.1. Khi nim:

nh lng sn phm dng bt nho ngha l phn chia lin tc t khi chung

ra thnh cc cc ring, c th tch xc nh v c trng lng tng ng bng nhau.

Trong khi phi m bo t trng cc cc cho ng u. V d nh trong sn xut

bnh m th sai s nh lng khng c vt qu 2,5% trng lng trung bnh cc

on.

4.2. Phn loi: Cc my nh lng th tch i vi bt nho thng gp nhngdng sau:

a/ Cc my nh lng ct cc bt nho t dng si c p u n t khun

p ra, nhng on y phi c hnh dng xc nh v c ct bng dao chuyn ng

vi tn s khng i;

b/ My nh lng c thng lng c np y bt nho v tho ra bng

phng php cng bc ;


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c/ Cc my nh lng loi dp ct cc bt nho thnh hnh dng v th tch xc

nh t bng chun b s b sn phm

4.2.1. My nh lng bt nho bng dao lc:

Cu to v nguyn tc lm vic:

1. phu cha2. khun p3. dao lcHinh 5.10a. My nh lng bt

nho c dao lc

Trn hnh 5.10a cho s my

nh lng ct tng phn bt nho bng

dao lc. Bt nho t phu cha 1 c mt hay vi vt xon cun ly v a i vi tc

khng i qua khun p 2 c profin v tit din xc nh; trong qu trnh cp liu

th khi sn phm c ln cht v bt buc phi chuyn ng lm cc si c ng

u ln v t trng. Dao 3 lc vi tn s u ct cc si bt thnh cc thi c chiu di

v th tch bng nhau.

4.2.2. My nh lng bng thng lng:

1. phu tip liu2. Trc cp liu3. Bung nhn4. Tm ct chn5. pittng6. thng lng7. c cu chia8. Pittng9. l xo10.bng ti

Hnh 5.10b. My nh lng bng thng lngTrn hnh 5.10b cho my nh lng c thng lng v c pittng thc ra tng

phn. T phu 1 sn phm c cc trc cn cp liu 2 a vo trong bung nhn 3.

Trong khi tm chn ct 4 v pittng 5 v tr tn cng bn tri. Tm chn 4 v pit

tng 5 di chuyn chuyn sang bn phi v bt u ct khi sn phm trong bung 3,

ri sau n c y vo thng lng 6 ca c cu chia 7.


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Thng liu cha y bt nho, cn pt tng 8 nn l xo 9 v v tr bn phi. Khi

quay c cu chia i 900 pit tng 8 c gii phng khi p lc ca pit tng 5 di tc

dng ca l xo 9, tng phn bt c y ra bng ti 10, tng phn bt ny bng th

tch thng liu.

4.2.3. My chia c thng lng v c cu chia quay lin tc: c ch trn

hnh 5.11. Thng c gn 1 cun bt nho i qua gia n v c cu chia 2, c cu chiac bung liu hnh tr 3, trong c pit tng 4 dch chuyn. Di p lc ca bt nho

li theo chiu su ca bung liu cho n ch ta ca con ln 5 trn cam nh hnh 6.

Khi bung liu i ngang qua mp nhn 7 th bt nho c ct ra khi khi sn

phm chung; khi cc con ln ln trn hnh qut c nh 8 th cc bt nho c pit

tng p t bung liu ln bng chuyn 9. Quay cam 6 c th iu chnh c trng

lng phn bt nho cn nh lng.

1. Tang tip liu2. C cu chia3. Bung cha liu nh lng4. Pittng5. Con ln6. Cam nh hnh7. Mp nhn8. Hnh qut c nh9. Bng chuyn

Hnh 5.11.My chia c thng lng v c cu

chia quay lin tc

4.2.4. My nh lng m vn thn

Trn hnh 5.12 cho bit s lm vic ca thit b nh lng p l mt b

phn ca my t ng sn xut m vn thn. N gm a p 1 vi khun p c hnh

dng xc nh, bng thp ca bng chuyn 2, bng chuyn 3 v khun p 4 cp btnho v tht xay.

Bt nho v tht xay c a vo khun p bng bm hi chuyn. Bt nho c

dng ng v tht xay c cp vo trong n thnh tng phn ring nh c b phn ct

bng kh nn.


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ng bt nho c ct bng dy tch khng kh. Khun dp ct ng bt

nho ra nhng thi vn thn m c cha phn tht xay. trnh dnh bt nho, ngi

ta bi trn khun dp bng du m.

Thit b nh lng tng t c dng phn lng m, men, lm bnh bch

quy, ko v nhng sn phm khc trong sn xut thc phm.

Hnh 5.12. S my nh lng m vn thn

1. a dp

2,3. bng chuyn

4. Khun p

5. NHNG MY NH LNG SN PHM THC PHM LNG.

5.1. Mc ch v phm vi ng dng.

- nh lng sn phm lng bng my c ph bin rng ri trong nhiu

ngnh sn xut thc phm. u im khi nh lng bng my :

. Ci tin c iu kin v sinh.

. m bo c nng sut cao.

. nh lng sn phm mt cch chnh xc.

- C ba phng php nh lng c bn: Trng lng, th tch v nh lng

theo mc trong ph bin nht i vi sn phm lng l hai phng php nh

lng th tch v nh lng theo mc.

- Cc yu cu i vi nhng my rt sn phm thc phm lng ch yu l donhng tnh cht vt l khc nhau ca chng quyt nh (to bt, nht, bay hi);

V d nh bia, sm pa v cc ung khc c cha kh, gim tn tht kh

cacbonnic th phi rt di p sut cao hn p sut kh quyn. Ngi ta to nn trong

bao b mt p sut cao bng p sut trong bnh ng cht lng chy ra.


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Nhng sn phm c cha vitamin (nc p hoa qu v rau) nn rt di chn

khng, trong trng hp ny gim c hm lng oxy trn mt sn phm trong bao

b kn.

i vi nhng my rt cc cht lng c bt th cn cc yu cu c bit.

5.2. Phn loi cc my rt:

Nhng my phn lng sn phm thc phm lng c th phn loi theonhng du hiu khc nhau. Trong bng 5.1 nu ra s phn loi ca my rt ph thuc

vo phng php rt cht lng, cu to ca my v cc b phn rt.

Bng

Bng 5.1. PHN LOI CC MY RT

Cc nhm

myCc ch s Cc phng php vt l, cu to v k thut thc hin rt

I Loi myC cu rt

bng tay

Bn t ng t ng

t ng theo

cc khi chi

tit

Lin hp bt

kn khc

nhau

II Cu to myMt rnh

thng

Nhiu rnh

thng

Kiu bn

quay- -

III

Phng

php np

cht lng

Di p

sut chiu

cao ct cht

lng khng

i

Di p

sut chiu

cao ct cht

lng gim i

To chn

khng trong

bao b np

y

Bm pit

tng

p sut ct

cht lng

trn c

kh

IV

Thit b

ng kn Kho nt Van

Ngt bng

khng kh Van trt bng hi

V C cu rt T 1 n 40

VI nh lng

Theo th

tch nh

bnh lng

di ng

Theo th

tch nh

bnh lng

c nh

Theo mc,

ngha l np

y bao b

n mc

bit

VIITc dng

ln b phn

ng kn

Nng mm

bn di,

trn c

bao b nh

c cu cam

c nh

Nng mn

bn di,

trn c

bao b nh

khng kh

nn

Cho dng

in vo

cun dy

ca van

hnh ng

xon.

- i vi nhng sn phm c nht nh: khi lng ring t 0,9 n

1,0g/cm3, v nht 0,8 - 8,5 centipoize nht nh: sa, crem, ru, nc, ru mi,


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bia, ru vang xi r, nc p, du thc vt, du c, dm ... th c th dng cc b phn

rt trong cht lng cn phn lng chy di tc dng ca trng lng (thit b rt,

trng lc).

- i vi nhng sn phm c nht cao hn (hng chc ln): nh dch c

chua, vng sa, dch rau, mt nh, kem cc ... ngi ta phn lng nhng sn phm y

nh p cng bc chng trong nhng dng c c bit ca my nh lng.5.3. Cc c cu rt ca my nh lng .

5.3.1.C cu rt kiu van

a.Cu to:

Hnh 5.13a. C cu rt kiu van nh Hnh 5.13b.Tnh tan tnh t chy khi

lng bng cch ngt khng kh thay i mc cht lng

1. Bnh lng2. Van 3 chiu3,4. ng

5. ng rt nguyn liu vo bao b

Trn hnh 5.13a, ch c cu rt kiu van n gin nht, n gm c bnh lng 1,

van ba chiu 2, ng 3, ng ni 4 np y bnh lng v ng ni 5 rt th tch

o lng vo bao b cha.b.Nguyn tc lm vic: Th tch cht lng i vo trong bnh lng 1 ph thuc

vo v tr u bn di ca ng 3 h c hai u.

Khi nt ca van ba chiu ti v tr ch phn bn phi ca hnh v, cht lng

di p sut thy tinh i vo trong bnh lng, y khng kh trong bnh ra qua ng 3.

Khi cht lng dng n mp di ca ng th khng kh khng ra c na, cn cht

lng trong bnh lng c dng ln cao hn mp di ca ng mt on, ph thuc


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vo mc cht lng trong thng rt. p sut khng kh trn cht lng s ngn cn vic

np tip tc vo bnh lng, cn li ra ca cht lng b ng; cht lng trong ng 3 s

dng ln v theo quy tc bnh thng nhau n c xc nh bng mc cht lng

trong thng rt. Nh th l chm dt mt chu trnh nh lng. Th tch c iu

chnh bng cch nng ln hoc h ng 3 xung.

tho cht lng vo bao b cha, th quay nt ca van ba chiu ngc kimng h mt gc 900, nh ch phn bn tri hnh v.

Tu theo cch quay van m nhng my dng c cu rt ny thuc loi quay tay,

bn t ng v t ng.

Cht lng chy ra cng nhanh, th nng sut my cng ln, trong nhng iu

kin khc ging nhau.

Giao an Mon Hoc Thiet Bi Thuc Pham

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