BOILER BLOWDOWN VALVES TYPE ODM1 ODM2FUNCTION:

Boiler Blowdown Valves type ODM-2 are pneumatically actuated. They are designed for blowing down steam boilers and waste- heat boilers. Thanks to the pneumatic actuation, the valves are suitable for supervision-free or controlled supervision service in installations with automatically controlled boiler blowdown process.

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CONSTRUCTION:The blowdown valve comprises two main functional units:- valve body,- pneumatic actuation ODM2, hand lever ODM1.Valve body is made of carbon steel.Valve seat is made from rolled stainless steel:H17N2.Valve plug is made from 4H13 material andsealed in the bonnet by means of a packing box.Pneumatic actuation unit includes a spring-loaded pneumatic actuator and a yoke. Thespring thrust provides for efficient valve shut-offtightness.

PRINCIPLE OF OPERATION:In order to initiate boiler blowdown, it is necessary to supply the actuator with pressure. The air supply is determined by valve nominal diameter and boiler pressure, and can be calculated from the following equation:

PS= 0,25 + PK x Xwhere:PS = air supply [MPa]PK = boiler pressure [MPa]X = area coefficient of plug and actuator.The blowdown process is completed within 3-4 seconds.Quick valve closing is due to a powerful spring thrust.

INSTALATION:

Boiler Blowdown Valves have flanged connections. Face – to – face dimensions and flanges are in accordance to PN. The valve should be mounted on a pipe so that the arrow on the body agreed with the fluid flow direction. The valve does not require servicing during operation. In case of leakage that cannot be eliminated by tightening of clamping screws, the valve should be send back for repair to the nearest service point or to the manufacturer.

POLNA ENGINEERING Sp. z o.o.ul. T. Kościuszki 227

40-600 Katowicetel. +48 32 781 85 17fax +48 32 750 06 65

e-mail: polna@polna-eng.plinternet: www.polna-eng.pl

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20 25 32 40 50

6 7 10 20 22

105 115 140 150 16575 85 100 110 125

14 14 18 18 18

4 4 4 4 4

160 160 180 200 230

80 80 90 100 115

80 80 80 85 90

with acutator 300 300 300 320 320

with lever 225 225 225 245 245

with acutator 19 19 21 26 31

with lever 15 15 17 22 27

0,035 0.075

Dimensions DNKvs coofficient

X

H

Weight[kg]

D

Do

dnL

L1

F

MATERIALS:- carbon steel GP240GH (1.0619)- stainless steel GX5CrNiMo 19-11-2, (1.4408)

BLOWDOWN DATA:

FIG.1 A: Condensate amount to be discharged [kg / h] S: Salt content in supply water [mg / l] Q: Boiler capacity [ kg / h] K: Allowable salt content in boiler water [mg /l] FIG.2 Valve capacity [kg / s] Boiler working pressure [MPa] Valve opening causes condensate and deposit discharge. At the time of blowdown also surface blowoff takes place. Blowdown frequency and duration, which influence surface blowoff, can be determined from the adjacent charts: 1. Fig.1 illustrates the amount of condensate that needs to be discharged within an hour in order not to exceed the allowable salt content in condensate.2. Fig.2 illustrates discharge amount in kg / s for a given valve.3. On the basis of the data given in paragraphs 1 and 2 above, it is possible to determine condensate discharge duration.4. On average, the blowdown takes from 3 to 4 seconds. If the result achieved from the above calculation as per paragraph 3 differs substantially, then the blowdown frequency needs to be modified. For example:a. result of calculation: 1,5 s per 1 hourb. we assume: 3 s every 2 hoursa. result of calculation: 7 s per 1 hour β. we assume: 3,5 s every 0,5 hour.

Example:• S: Salt content in supply water : 1 500 mg / l• K: Allowable salt content in boiler water: 5 000 mg /l• Q: Boiler capacity: 1 000 kg / hThus A: condensate amount discharged = 31 kg / h as per Fig.1 Sample calculation of discharge duration as per Fig.2:• boiler working pressure: 2,5 MPa• valve size: DN 25• valve capacity: 10 kg / sthus discharge duration = 31 kg / h : 10 kg / s = 3,1 s