Design Guide for Air Slide Conveyor
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Transcript of Design Guide for Air Slide Conveyor
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No Subject Requirement (Rule of thumb & Application) References and notes
1 Aerated bulk material density 0.66 multiply by bulk density DCL, if aerated bulk density is not known
2 Applicated material density for air slide conveyor 5 up to 200 lb/ft^3,
For material has angle of repose 35 up to 40 deg is categorized as most free
flowing material (Book)
DCL
For bulk density 70PCF - 20inch WG in plenum chamber
For bulk density > 70PCF - 27inch WG in plenum chamber
DCL,
70PCF 1.24ton/m^3
20 inch WG 50 mBar
27 inch WG 67 mBar
400 mmWG 40mBar FLSmidth
unknown DCL
Permeability 1.5 m^3/m^2.min, Pressure drop 100mmWG (10mBar) FLSmidth
For case P630, length 35m and diaphram area is 0.63*35 =
22.05 m^2, check fan capacity selected from graphical table
43m^3/min (40mBar)
Air ow rate through Porous Membrane=
1.5m^3/m^2.min * 22.05m^2 = 33 m^3/min
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Safety factor for air flow rate for fan according to porous
membrane requirement is about 43/33 SF1.3
8 deg, but may be as low as 6 degrees depending on product material type. DCL , Most product suitable for air gravity conveying are handled
on a conveyor sloped at between 6 and 12 degrees. The slope can
be reduced to 1 or 2 degrees for product which have excellent
fluidizing characteristics.
7 deg, currently aplicated on Tonasa V project is 7 deg (not as minimum but
applied conveyor angle)
FLSmidth, The areated material flows like a liquid
at a suitable inclination of the conveyor
(4o-15
o) depending on the type of material
conveyed
5 Minimum sugested conveyor angle
DESIGN GUIDE FOR AIR SLIDE CONVEYOR
Pressure required for close type conveyor3
Permeability and pressure drop of Porous DIAPHRAM4
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6a The volume of free air required (Fan flow rate) 10 SCFM (Standard cubic feet per minute) per square foot
Dimension of air slide conveyor of DCL
A=24 inch (2 ft), length=35m (115 ft)
Membrane area = 2 x 115 (ft^2) = 230 ft^2
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Free air requirement = 10 SCFM/sqft * 230 sqft = 2300 SCFM (65 m^3/min)
Fan flow rate = standard 65 m^3/min
DCL
The volume of free air required for most applications is
approximately 10 SCFM per square foot of conveying media when
handling a product like cement, fly ash, phosphate rock dust, and
lime products. However the air requirements may vary for other
materials from 4 to 15 SCFM (standard cubic feet per minute) per
square foot. In conveying alumina and bauxite, the air
requirement for fluidization can be as little as 4 SCFM. Please be
aware that there is no definite formula for calculating the volume
of free air required. In order to establish the proper air
requirements for materials not previously handled, DCL offers
testing at their facility
6b Handbook of pneumatic conveying engineering
Chapter 18. Fluidized motion conveying system
Basic property of cement portland:
1. Bulk density : 1,070kg/m^3 67lbs/ft^32. Particle density : 3,060kg/m^3 191lbs/ft^3
3. Mean particle size : 14m --------------------------------------------------------------
Taken from table that (approximation)
Terminal velocity needed is 5ft/sec 0.025m/s
Porous membrane area is 230ft^2 21.37m^2
Fan ow rate is 0.025m/s*21.37m^2 0.534 m^3/s
32m^3/min
SF=1.3 (FLSmidth - previous result)
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Fan flow rate requirement = 1.3 * 32m^3/min 42m^3/min
Fan flow rate = standard 42m^3/min
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6c FLSmidth
Fan flow rate based on P630 and conveying distance 35m is 43
standard m^3/min
Fan flow rate = standard 43m^3/min
7 Air supply interval Up to 100 m FLSmidth
8 Air pressure for open type conveyors installed in
silos or hoppers are generally determined by the
head of product over the conveyor
Air pressure for all material:
head product over conveyor, H< 2ft - 1PSI
head product over conveyor, 2H15ft - 6PSI
Except for alumina, pressure of 3 PSI is adequate regardless of head
DCL, pressure up to 1PSI can be supplied by centrifugal blower
and pressure greater than 1PSI should be supplied by positive
displacement blower . A high pressure compressor plant is not
recommended for use in supplying fluidization air as this source is
considered dirty air meaning the presence of water and oil
9a Standard dimension of conveying channel Fuller Airslide Conveying Technology, FLSmidth
For example,
Material Cement Portland (A36M/A16M)
A36M: 1.27 up to 1.75 ton/m^3
A16M: 1.06 up to 1.32 ton/m^3
Angle of repose 30-44 deg
For A=600 Nominal capacity > 1,500 m^3/h
For A16M Cement portland, the capacity is > 1,500 ton/h
9b DCL
24 inch (600 mm) - 39,000 ft^3/h 1,100m^3/h
For A16M Cement portland, the capacity is > 1,100 ton/h
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9c FLSmidth
For example,
For P630, capacity range is from 250 up to 1000 m^3/h
For A16M Cement portland, the capacity up to 1,000 ton/h
Conveying angle minimum 4 deg , apllied 7 deg
For 35m conveyor length, Fan capacity 35m^3/min (based on
400mmWG air pressure)
9d Conveyor box width (b) 0.65 (mass flow rate/particle density)^0.5
Mass flow rate = 800 ton/h
Cement portland (non aerated) density = 72 ~ 99 lbs/ft^3 85lbs/P^3
0.5 as aspect ratio (depth/width of flowing bed)
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b 0.65 (800/85)^0.5 2ft 610mm
Handbook of pneumatic conveying engineering
Chapter 18. Fluidized motion conveying system