Boiler Accessories Flashcards
What is a gate valve?
A gate valve is an isolation valve that is not intended for throttling applications. When fully open the gate valve offers very little resistance to flow.
What is a globe valve?
A globe valve is an isolation valve that is intended to throttle flow. When fully open the globe valve offers some resistance to flow.
What does a check valve do?
A check valve allows flow in only one direction. A swing check is used on horizontal runs of pipe and lift check is used for vertical runs of pipe. An arrow on this valve indicates direction of flow.
What is the purpose os the main steam stop valve?
The main steam stop valve is used to isolate the boiler for inspection/repairs or cleaning.
What is the purpose of a non-return valve?
The non-return valve sis an isolation valve that allows the flow os steam out of the boiler only. It should be locate as close to the boiler as possible.
What is slow-operating valve? A quick opening valve?
A slow opening valve requires more than 5 (five) full turns to be fully open. A quick opening valve require less than 5 full turns to be fully open.
How do you blowdown a boiler?
Blowdown a boiler: find the true water level, have 1/2 (half) a gage glass or better, open cooling water to blowdown tank, open quick opening valve, open slow opening valve fully wide and close it, close quick opening valve, check column and glass and secure cooling water to blowdown tank.
How do you fin “true after level” in a boiler?
You find the “true water level” by blowing down the water column and the gage glass. Blowdown the connections to the gage glass independently to assure that there is no blockage.
How does pressure gauge work?
A pressure gauge utilizes a bourdon tube to indicate pressure. A hollow tube close at one end is connected to linkage and an indicator. As pressure is applied this tube straightens and indicates the condition on a calibrated face.
What is the difference between a blow-down tank and a flash tank?
A blow-down tank tempers the blowdown before discharging to sewer. A flash tank recovers heat from the blowdown in addiction to tempering the blowdown.
A pressure gauge reads 200 PSI. What is the absolute pressure?
The absolute pressure would be 214.7 PSIA. 200 PSI + 14.7 = 214.7 PSIA.
How often would you test the “low water cut-out”?
The low water cut-out should be tested at the start of every shift.
What is an open feed water heater? A closed feed water heater?
In an open feed water heater the steam and water come in direct contact such as a D.A. In a closed feed water heater the steam and water do not come in direct contact such as a shell and tube heat exchanger.
Where in the boiler room is a check valve required?
The ASME code dictates that a check valve will be placed on the feed water line between the feed pump and the boiler.
The boiler just tripped on low water. What will you do?
Continue to feed water to the boiler and troubleshoot the cause of the low water. When corrected, purge boiler and relight.
