2. Function Of
Feed Check
Valve:
• The function of the Feed
Check Valve is to control
the supply of waterto the
boiler and prevents the
back flow of waterfrom
the boiler when the feed
pump pressure is less than
boiler pressure or pump is
stopped.
3. Construction Of Feed
Check Valve:
The Feed Check Valve is fitted
in the water space of the boiler
just below the normal water
level of the water.
It consists of non-return valve,
water inlet pipe, outletpipe,
spindle, gland and hand wheel
a shown in diagram.
The outlet pipe of valve
connected with boiler and inlet
pipe connected with end of
delivery pipe of feed pump.
4.
5. Working Of Feed Check
Valve:
The lift of the valve is controlledby
moving the spindle up and down with
the help of the hand wheel. So flow of
water is controlled. If pump is fail or
stop due to any circumstances,the
pressure on pump side is lower than
the boiler pressure.
Resulting the downward force on non-
return valve is higher. Therefore valve
sits on its seat and closes the passage.
This will prevent the back flow of water
from boiler to the water pump.
Inlet and outlet pipe of valve exposes
different pressure. At inlet of valve the
feed pump pressure acts and outlet
pipe of valve the boiler pressure act.
When feed pump is in operation, the
pressure on the feed pump side (inlet)
is more than pressure on the boiler side
(outlet).
This pressure differencelifts the non
return valve,and allows water flow
into the boiler.