6 replies to this topic

[betty]

Dear:

The check valve is only in Centrifugal pumps…Why? Where?


There are suction valve and discharge valve acting (as check valve) in reciprocating pump.?


Regards

[mohamedbadawy]

my friend, from the meaning of the valve you can choose or decide when to use it; by means : its name is Check valve or Non return valve, so you can use on lines that you don't need a backflow in it, or to prevent the backflow in this line; and this is happened when you have a sudden pressure drop after and before a certain point in a line that you have a reverse wave - high amplified or dangerous waves" like in case of after shut-off pumps" for this reason we use it after pumps

[betty]

Thanks for such replay..

Yeah as you metioned exactly..

But I'm wonderliing why do they put check valve after pump, just to prevent backflow, or there is another reasons?

Best Regrads

Edited by betty, 13 January 2012 - 07:34 AM.

[pavanayi]

Betty,
The check valve is present to prevent any backflow through the pump.
When the pump is pumping, it delivers liquid from low pressure (suction) to high pressure (discharge side). If the pump trips due to any reason, there is a driving force for the liquid to flow from the discharge piping (high pressure area) into the suction piping (low pressure area) through the pump casing, which will 1. Damage the pump and 2. May overpressurise the upstream piping/components/vessels which are not designed for the high pressure.

So, to prevent the backflow through the pump, check valve is installed just after the pump discharge.

Edited by pavanayi, 13 January 2012 - 08:55 AM.

[betty]

Thanks for such clarification.

[fallah]

The check valve is only in Centrifugal pumps…Why? Where?

betty,

Check valves, at least, shall be provided at below situations to prevent back flow:

1) Discharge of centrifugal and rotary pumps and compressors
2) Discharge of dosing and volumetric pums
3) Utilities and sevice lines (e.g. chemical injection line) permanently connected to process lines or equipment

Fallah

[27hours]

There are several types of check valve. simply swing type and non slam check valve.
If discharge flow of pump and compressor has fluctuation or pulsation due to types of rotating machines, non slam check valve is used for protecting piping damage.