12 Questions
What is the minimum number of safety valves required to be fitted to the boiler for them to be considered efficient?
2 safety valves
Why is it essential for the springs and valves of safety valves to be within a lockable casing?
To prevent excess pressure build-up
What material is commonly used for the fabrication of the valve, valve seat, valve stem, and lock nut of safety valves?
Bronze
Why is it important for the valve lift to be equivalent to ¼ of the diameter of the valve in safety valves?
To allow for full steam flow
Where is the safety valve independently mounted?
On a separate port on the boiler shell
Why must no other valves be fitted between the boiler shell and the safety valve?
To ensure proper functioning of the safety valve
How does the setting of the safety valve on the superheater compare to the other 2 safety valves?
It is set at a lower pressure
What triggers a safety valve to lift off its seat and allow steam to escape?
Pressure pushing against the valve
How are main steam stop valves typically designed in single boiler installations?
Screw down - screw lift type
What is the purpose of having a screw down, non-return type main steam stop valve in multiple boilers connected?
Prevent steam from other boilers flowing into a damaged boiler
How are valve seats maintained in position for cast steel, self-closing main steam stop valves in water tube boilers?
Pressed in and chest peened over
What additional safety feature may be incorporated in some main steam stop valves to protect a steam turbine?
Emergency self-closing mechanism
Test your knowledge on safety valves that protect boilers from over pressurization and their independent mounting on the boiler shell. Learn about the requirements set by the Department of Transportation regarding the number of safety valves needed for a boiler.
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