ERV Floating Procedure

7/23/2019 ERV Floating Procedure

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PROCEDURE FOR

ELECTROMATIC RELIEF VALVE FLOATING

Document No: PWR/TSX/BLR/03/247/00/11

Bharat Heavy Electricals Limited

Power Sector: Technical Services

Kribhco Bhawan, A-8-10, Sector 1, Noida, 201301



P R O C E D U R E F O R

E L E C T R O M A T I C R E L IE F V A L V E F L O A T I N G

Procedure fo r E lect romat ic Re l ie f Va lve F loa t ing

Docum en t No : PW R/TSX/BLR/0 3 /2 4 7 /0 0 /11

N a m e

D es igna tion S ig na tu re

Prepared by :

D H R U V G A R G

Sr. Eng ineer Boi ler)

D1\91tAl 1 Y

Rev iewed by :

G. Mura l i

AGM Boi ler )

I s s u e d b y :

N . K B a n s a l

G M P S - T S )

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Date of Issue

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Pow er Sector : Technical Serv ices HQ )

Kribhco B haw an, A-8-10, Sector 1, Noida, 201301

P o w e r S e c t o r — T e c h n i c a l S e r v i c e s

ocumen t No: PWR /TSX/BLR/03/247/00/11

2



PROCEDURE FOR


Power Sector – Technical Services Document No: PWR/TSX/BLR/03/247/00/11

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Content

S. No. Description Page No.

1. Objective 4

2. Electromatic Relief Valve (ERV) Assembly, System &

Terminology4

3. ERV Floating Principle 7

4.

Checks for ERV Floating (Mechanical & Electrical) 7

5. Pre – Floating Activity 8

6. Safety Precautions 8

7. Safety Equipments 8

8. Procedure for ERV Floating 9

9.

ERV Setting Values 10

10. Appendix 1: ERV Details in a typical drawing for “Safety

Valve Setting for Boiler, Superheater, Reheater & Soot

Blower” for a 500 MW Boiler

11



PROCEDURE FOR



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1.

Objective

Electromatic Relief Valve (ERV) is provided in the system to prevent boiler pressure

going beyond the required level at any load by operating it electrically from remote

according to requirement and to prevent frequent operation of safety valves, therebyincreasing its life and availability.

ERV Floating is one of the last commissioning activities before boiler is ready for load

operations. The objective of ERV Floating activity is to determine and ensure:

Popping or Set Pressure for the ERVs

Clean popping of the ERVs

Reseating or Closing Pressure of the ERVs

Clean reseating of the ERVs

Blowdown for the ERVs

Cleanliness of the ERVs and its exhaust system

2. ERV System, Assembly & Terminology

Isolating Valve – Shown in Figure 1. It is the mechanical isolating gate valve provided

for isolating ERV from the system.

Pilot Valve – Shown in Figure 1. Pilot Valve is the main component of ERV which

when operates relieves the pressure of the system.

Solenoid Assembly – Shown in Figure 1. Solenoid gets energized from electrical

supply via actuated pressure switch, which in turn operates the pilot valve.

Control Station – Shown in Figure 1. Control Station is equipped with 3 point switch

(manual, off and automatic) and corresponding 3 lamps (red, blue & green). Green

light indicates auto position. Blue light indicates system pressure reaching the set

point or corresponding relay for pressure switch has been energized at manual

position. Red light glows, when the valve remains open fully at the time of floating.

Hand operation is performed by putting the switch to manual position for opening

and then to ‘off’ position for closing.

Controller – Shown in Figure 1. Controller houses pressure switches for set & reseat

pressure and get impulses through impulse line originating from MS Line. By

adjusting the screws, the operating point (i.e. set pressure & blowdown) can be

decided.

Set Pressure – Pressure at which ERV starts floating. Basically, it is the gauge

pressure at the valve inlet, for which the ERV is adjusted to open under service

conditions.

Reseat Pressure – Pressure at which ERV stops floating i.e. the pressure at which the

disc reseats.



PROCEDURE FOR



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Blow Down – It is the difference between set pressure and reseating pressure

expressed as a percentage of the set pressure. It signifies the amount of pressure

relieved from the system.

Blowdown (%) = (Set Pressure – Reseat Pressure) * 100

Set Pressure

Figure 1: Electromatic Relief Valve System



PROCEDURE FOR



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Figure 2: Electromatic Relief Valve Assembly

Nomenclature List (for Figure 2)

226 Base Stud 344 Disc

229 Nut 345 Guide

303 Main Base 347 Disc Spring

305 Inlet Neck 351 Pilot Seat Bushing

307 Support Plate 355 Pilot Disc

311 Pilot Valve Tube 356 Pilot Stem

322 Nipple Extension 376 Pilot Spring

323 Discharge Collar 377 Pipe ELL

324 Pipe Elbow 378 Pipe Nipple

332 Solenoid Assembly 379 Lever

341 Seat Bushing – Main 383 Solenoid Plunger Head



PROCEDURE FOR



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3.

ERV Floating Principle

ERV Floating principle is explained below with the help of Figure 2 giving details of ERV

Assembly.

Steam under pressure from the superheater enters the main valve through the inletchamber A, and passes upward around the disc guide, to chamber B, steam enters

chamber C through the clearance space between the main valve disc (344) and its guide

(345). The main valve disc (344) is held in the closed position by steam pressure in

chamber C. the pressure in chamber c is the same as in chamber b when the escape

through port D is prevented by the closure of the pilot valve disc (355). The pilot valve

disc (355) is held in the closed position by pilot valve spring (347) and by the steam

pressure in chamber E. It is opened by the operating lever (379) under the action of the

solenoid plunger head (383). When the pilot valve is opened steam is released from

chamber D through port F at a faster rate than supplied through the clearance space

between the main valve disc and the main valve disc guide. The resultant unbalance ofpressures in chambers B and C produces a force which moves the main valve disc from

its seat, permitting steam to escape from chamber B to outlet G.

4.

Checks for ERV Floating

Mechanical Checks

Visually inspect all the ERV for correction erection and installation as per drawing.

No load transmission from discharge piping to ERV.

Vertical installation (within ± 1˚).

Body drain to a safe area.

Adequate 360⁰ access around valve & overhead.

Controller away from location of vibration and several looping in impulse pipe.

Slope of impulse line towards the controller & provided with siphon.

Gap between solenoid plunger end and pilot valve operating lever is 22.7 to 35.4

mm.

Pressure connection at 8 to 10 pipe dia. upstream from ERV.

Electrical Checks

Terminal connection correctness w.r.t. wiring diagram.

Installation of recommended fuses.

Power supply.

Cut off switch in solenoid for proper function.

Pressure switch for correct range.

Smooth action of solenoid by pressing.



PROCEDURE FOR



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5.

Pre – Floating Activity

Close the ERV Isolating gate valve.

Put the switch on ‘Auto’ and green light will indicate correctness.

Turn the switch to ‘Manual’. Measure the movement of solenoid plunger. It should

press the operating lever in such a way that pilot stem moves by 2.4 to 3.2 mm.

Red and blue lamps should be glowing now. Blue lamp shows that relay is energized.

Red light shows that plunger has reached the bottom of stroke i.e. the valve has

opened.

Put the switch back to ‘Auto’. Red & blue lights should go off. Solenoid & opera ting

lever returns to normal position.

Put the switch to ‘off’. All lights should go off.

6.

Safety Precautions

a) Do not stand in front of discharge side of an ERV during floating.

b) Never install a ERV in a horizontal position, as they are designed for vertical

operation only. Always provide Isolating Valve for ERV to isolate it from the system.

c) Drains of ERV must be piped to a safe area.

d) 360⁰ and overhead access to ERV should be there.

e) Minimum number of people, only who are required for the floating & setting of ERV

should be present on the ERV floor during the activity.

f)

Cordon off the area where valves are going to be tested to avoid trespassing during

the activity and warn people at the site about the activity and precautions to be

taken.

g) Use safety equipments listed in the section of Safety Equipments for personnel

safety from noise and high temperature during the activity.

7. Safety Equipments

a) Asbestos Gloves

b)

Safety Helmetc) Ear Muffs

d) Eye Protector

e) Safety Shoes

f) Protective Clothing

g) First Aid Box (Containing – Eye Lotion, Tincture of Iodine, Burnol, Bandages, Cotton

etc.)



PROCEDURE FOR



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8.

Procedure for ERV Floating

Light up the boiler following O&M instructions. Keep Main Steam Stop valve closed.

Raise the pressure to 35 kg/cm² and hold.

Disconnect the impulse line from controller and steam flush the line for 15 – 30

minutes by opening isolation valve.

Restore back the impulse line.

Open slightly the ERV isolation gate valve. Allow at least 30 minutes for warming up

of valve. Open the isolation valve fully.

If valve leakage is visible (it can happen due to entrapment of dirt or scale in seat),

operate the switch on ‘Manual’ for few seconds. If the valve leakage persists even

after 5 minutes of operation, valve seat requires rectification.

Increase the boiler pressure. As the pressure increases, first the low pressure (closing

pressure) switch indicating light will glow indicating its actuation. On further increase

of pressure, ERV will pop.

Note down the popping pressure & blow down. Check set pressure, reseat pressure

and blowdown for the ERV in the Safety Valve Details Chart provided in the drawing

“Safety Valve Setting for Boiler, Superheater, Reheater & Soot Blower” (Typical

Drawing No.: 2 –00 –047 –XXXXX). A typical drawing for ERV Setting for 500 MW Boiler

is enclosed in Appendix 1.

If popping pressure is less than recommended, turn the corresponding setting screw

counter clockwise. For decreasing popping pressure, turn it clock-wise.

For setting blow down, the recommended graph (as in Figure 3) may be referred. By

turning corresponding setting screw for blow down, same can be increased

(clockwise) or decreased (counter clockwise).



PROCEDURE FOR



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Figure 3: Typical Graph for Setting Blowdown of SH ERV

9.

ERV Setting Values

A typical set of values for ERV Setting for a 500 MW Boiler is given in Table 1 as below.Table 1: Typical ERV Setting Values for a 500 MW Boiler

S.No. Location Valve

Tag No.

Valve Model No. Valve Set Pressure

(in kg/cm2) (G)

Blowdown

(%)

Type Of Valve

OPEN CLOSE

1. Super Heater SV9 CONSOL 1538 VX-10W 185.5 180.3 2.8 ERV




5. Super Heater SV13 CONSOL 1538 VX-10W 186.6 180.6 3.2 ERV6. HRH SV22 CONSOL 1525 VX 48.4 47.1 2.7 ERV

7. HRH SV23 CONSOL 1525 VX 48.4 47.1 2.7 ERV





Appendix 1:

ERV Details in a typical drawing for “Safety Valve Setting for Boiler, Superheater, Reheater & Soot Blower” for a 500 MW Boiler



DISTRIBUTION LIST

Regional / Other Heads

ED, PS-NR, Noida

ED, PS-ER, Kolkata

ED, PS-WR, Nagpur

ED, PS-SR, Chennai

GM (I), CQ, Noida

Regional Project Site Heads

GM (PMX, CFX, MSX & IT), PS-NR

GM(Anpara & Harduaganj), PS-NR

GM (GGSR) , PS-NR

GM(SCP, Commrcl), PS-NR

GM (GVK Goindwal), PS-NRGM(Jhajjar), PS-NR

GM (Pariccha), PS-NR

GM(Bawana), PS-NR

GM (TSX) , PS-NR

GM (Dadri & Farakka), PS-NR

GM (Nalco Damanjodi) , PS-SR

GM (Vallur) , PS-SR

GM (North Chennai) , PS-SR

GM (Neyveli) , PS-SR

GM (SAS) , PS-SR

GM (Malwa) , PS-SR

GM (Tuticorin) , PS-SR

GM (Rihand & Vindhyachal), PS-WR

GM (Pipavav) , PS-WR

GM (Satpura) , PS-WR

GM (Hazira) , PS-WR

GM (Project & Pur) , PS-WR

GM (Bina Power) , PS-WR

GM (Project - I) , PS-ER

GM (Project II) , PS-ER

GM (Project III & IV) , PS-ER

GM (Project V) , PS-ER

GM (Project VI) , PS-ER

GM (Project VII) , PS-ER

GM (WBPDCL Projects) , PS-ER

Regional Commissioning Heads

AGM (TSX), PS-WR, Nagpur

AGM (TSX), PS-SR, Chennai

AGM (TSX), PS-NR, Noida

AGM (TSX), PS-ER, Kolkata

For kind information

For kind information and wider

circulation among Site

Engineers

For kind information and

wider circulation among

Commissioning Engineers



Regional Service Center Heads

RSM – Noida

RSM – Chandigarh

RSM – Varanasi

RSM –

Nagpur

RSM – Baroda

RSM – Secunderabad

RSM – Patna

Engineering Heads/Others

AGM (Engg.), BHEL – Hyd

GM (I) (Engg.), BHEL – Trichy

GM (Engg – FB), BHEL – Trichy

AGM (FES-FBC & HRSG), BHEL –

Trichy

AGM (Engg-FBC & HRSG),BHEL – Trichy

Regional Project Site In-charge/ Construction Manager

CM, Barsingsar, PS-NR

CM, Bawana, PS-NR

CM, Chabbra, PS-NR

CM, Dariba, PS-NR

CM, Dadri, PS-NR

CM, Jhajjar, PS-NR

CM, Farakka, PS-NRCM, Anpara D, PS-NR

CM, GVK Goindwal, PS-NR

CM, Harduaganj Extn, PS-NR

CM, Kosti, Sudan, PS-NR

CM, GGSR Refinery, PS-NR

CM, LM Bhatinda, PS-NR

CM, Obra, PS-NR

CM ,Parichha, PS-NR

CM, Abhijit, PS-ER

CM, Adhunik, PS-ER

CM, Bakreshwar, PS-ER

CM, Baramura, PS-ER

CM, Bongai RPL , PS-ER

CM, Barauni IOC, PS-ER

CM, Barauni TPS, PS-ER

CM, Barh Stage II, PS-ER

CM, Bokaro A, PS-ER

CM, Chandrapura, PS-ER

CM, Durgapur, PS-ER



distribution to service

engineers


wider circulation among Site

Engineers



CM, Haldia (IOCL & HMC) , PS-ER

CM, IISCO Burnpur Project, Asansol, PS-ER

CM, Kahalgaon STPP, PS-ER

CM, Korba West, PS-ER

CM, Koderma, PS-ER

CM, Lakwa, PS-ER

CM, Lepetkata, PS-ER

CM, Maithon, PS-ER

CM, Marwa, PS-ER

CM, Mejia, PS-ER

CM, MTPP-Kanti, PS-ER

CM, NTPC Bongaigaon, PS-ER

CM, Paltana, PS-ER

CM, Santaldih, PS-ERCM, Sidhriganj, Bangladesh, PS-ER

CM, TISCO - Jamshedpur, PS-ER

CM, Teesta, PS-ER

CM, Vizag, PS-ER

CM, Bharuch, PS-WR

CM, Bhusawal, PS-WR

CM,BORL Bina, PS-WR

CM, Bina Power, PS-WR

CM, Bhilai, PS-WR

CM, Hazira, PS-WRCM, Hindalco Mahan, PS-WR

CM,HZL, PS-WR

CM,IOCL (IRUP) , PS-WR

CM,JPL Raigarh, PS-WR

CM, Khaperkheda, PS-WR

CM, Korba, PS-WR

CM, Paras, PS-WR

CM, New Parli, PS-WR

CM, Kutch Lignite, PS-WR

CM, Monnet Ispat Project, PS-WR

CM, Nagothane, PS-WR

CM, Chandrapur, PS-WR

CM, Pipavav – Amreli, PS-WR

CM, Sikka, PS-WR

CM, SLPP Mangrol, PS-WR

CM, Sulaymaneyah, PS-WR

CM, Ukai # 6, PS-WR

CM, SAIL Rourkela, PS-WR

CM, India Bulls, PS-WR



CM, Avantha Power - 1, PS-WR

CM, Avantha Power – 2, PS-WR

CM, Rihand-5 & 6, PS-WR

CM, Amarkantak, PS-SR

CM, Bellary, PS-SR

CM, RINL Vizag, PS-SR

CM,HPCL Vizag, PS-SR

CM, Kakatiya, PS-SR

CM, Kalwakurthy, PS-SR

CM, Kothagudem, PS-SR

CM, KRL Kochi, PS-SR

CM, Kundakulam, PS-SR

CM, Kuttiyadi (Kerala) , PS-SR

CM, Muddanur, PS-SRCM, Nalco CPP, PS-SR

CM, Nalco Damanjodi, PS-SR

CM, Nettampad, PS-SR

CM, Neyveli, PS-SR

CM, NINL Duburi, PS-SR

CM, North Chennai Stage II, PS-SR

CM, Raichur, PS-SR

CM, Simhadri Stage II, PS-SR

CM, Sipat, PS-SR

CM, Vallur, PS-SR

Safety In-charge

DGM- QLY & HSE, PS-ER

AGM-FEX, PS-NR

Management Representatives

AGM (Quality & IT), PSNR – Noida

SDGM (Quality), PSWR – Nagpur

AGM (Quality & PLC), PSER –

KolkataAGM (Quality) SR – Chennai

Power Sector - Technical Services

GM (PT & ADMIN)

GM (TS)



ERV Floating Procedure

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