8/9/2019 Boiler Safety Valve

1/2

Introduction: Marine Boiler Safety Valves

The pressure setting of the superheater safety valve should be less that the designed pressure

of the boiler, i.e. less than that of the steam drum safety valve, to ensure flow of steam

through the superheater under blow off conditions. The pressure setting of one steam drum

safety valve should be same as the design pressure of the boiler. The pressure setting of

another safety valve should be 2-3 % more than the designed pressure of the boiler.

Read more:

http:www.brighthub.comengineeringmarinearticles!!"#2.asp$i$&&'23()v!bi

Pressure Setting of the Boiler Safety Valve:

*f it is found that the boiler safety relief valve is not lifting at the designed lifting pressure,

manual pressure setting of the boiler safety valve has to be done for the proper and safe

operation of the boiler. The ad+ustment can be carried out on this type of valve to give the

desired discharge and blow down characteristic.

'. afety valve pressure setting can be done from high to low pressure or vice versa.

2. Tae necessary personal safety precaution and arrange tools i.e. gagging tool and

master gauges.

3. lowly raise the boiler pressure and blow off the safety valves manually few times for

thermal e$pansion and to reduce the thermal stress on the valves.

#. Then screw down all the safety valves higher than the setting pressure at which you

are going to set.

). Raise the boiler steam pressure 2-3 % more than the designed pressure of the boiler,

then stop firing and unscrew the first valve slowly, when it blows off at 2-3 % more

than the designed pressure then note this opening and closing pressure of the valve

and finally gag it.

". Raise the boiler pressure at the designed pressure of the boiler and unscrew the 2nd

valve, when it blows off at designed pressure then note this opening pressure and

chec the closing pressure also. Rechec the setting pressure and gag the valve.

!. Then set the superheater safety valve lower than the designed pressure of the boiler in

same procedure.

. /inally tae out the gagging tools. 0ressure setting should be done in presence of

surveyor.

http://www.brighthub.com/engineering/marine/articles/77642.aspx#ixzz123W5v7bihttp://www.brighthub.com/engineering/marine/articles/77642.aspx#ixzz123W5v7bi

8/9/2019 Boiler Safety Valve

2/2

Read more:

http:www.brighthub.comengineeringmarinearticles!!"#2.asp$i$&&'23(**s$1

http://www.brighthub.com/engineering/marine/articles/77642.aspx#ixzz123WIIsxYhttp://www.brighthub.com/engineering/marine/articles/77642.aspx#ixzz123WIIsxY