4th Class Power Engineering Part B Unit 3 - Boiler Safety Devices

4th Class Power Engineering Part B Unit 3
- Boiler Safety Devices
35 kPa - ANS For a steam heating boiler, the safety valve shall be such that, with the
fuel burning equipment installed and operated at maximum capacity, the pressure
cannot rise more than _____ above the maximum allowable working pressure when all
steam outlets are closed




A
The Manufacturer - ANS LP boiler safety valves can be repaired by this




VI
Steam pressure acting on the disk of the valve - ANS A boiler steam drum safety
valve opens by means of




TU
Screw the blow down ring downwards - ANS To raise only the closing pressure of the
valve, one would

Perform an accumulation test - ANS If you are not sure that the safety valves are of
IS
sufficient capacity for the boiler, you would

Lip - ANS A part on a safety valve that allows it to pop open
OM

Pressure is up to at least 34 kPa - ANS On steam heating boilers, the safety valve test
lever must not be used unless

Monthly - ANS A steam heating boiler safety valve lever test should be performed
NA


20 kPa - ANS For hot water boilers operating up to 400 kPa, a pressure relief valve
opening pressure tolerance may be as much as
JP




Blowdown of a Safety Valve - ANS Defined as the difference between opening and
closing pressures

Suddenly increased due to a larger area - ANS Safety valves "pop" open because the
force of the steam is

6% - ANS Safety valves must be large enough to discharge all the steam a boiler can
produce without allowing the pressure to exceed the maximum allowable working
pressure by more than

, DN 15 (½ in) - ANS According to the current code no safety valve on a steam heating
boiler shall be smaller than

DN 100 (4 in) - ANS According to the current code no safety valve on a steam heating
boiler shall be larger than

Operate the test lever two or three times in order to allow the disk to seat - ANS After
checking a safety valve using the try lever, the valve continues to simmer after closing.
In order to close the valve fully the operator should




A
Increased or decreased by up to 5% - ANS The popping pressure of a safety valve




VI
may be

Manufacturer Representative - ANS The only person who can adjust the opening




TU
pressure or popping point of a safety valve is a

At least two - ANS If a boiler has 57 square metres of heating surface, it must have
___________ safety valves
IS
Increase the amount of blowdown - ANS Raising the blowdown ring on a pop safety
valve will
OM

Vertical - ANS The safety valve on steam boiler shall be installed in the _____ position
and located in the highest practicable part of the heating boiler proper

Stop Valve - ANS Device that is NOT allowed before or after the safety valve
NA


Melting of the alloy in a fusible plug - ANS Temperature relief valves can open on a
rise in temperature by the expansion of a wax-filled rod or by the

Adjusting Ring - ANS The blow down on a safety valve is adjusted by turning the
JP




Disc Area - ANS The force of the steam pressure acting on the safety valve disc is a
function of the

Seal - ANS Device that a boiler inspector will install in order to prevent tampering with
a safety valve setting