Pump Pulsation Damper Required 1

[ChemEngSquirrel]

I'm installing a positive displacement pump in chemical injection service (offshore facility). How can i determine if a pulsation damper is necessary?

 

[ione]

Which kind of pump do you intend to install?
What I mean is that the number of pistons is not a trivial information on this one as multiple pistons pumps will exhibit smoother pulsations.

 

[Pumpsonly]

It all depends on how much pressure and flow fluctuation your process can tolerate.Pulsating flow will also cause higher stress in your piping and fittings.

A simplex , long stroke, low RPM pump will have highest pulsation. If your injection rate is relatively high, using a multiplex pump may reduce the pulsation to an acceptable level without a dampener. Of cause the will also be more costly.

 

[bimr]

It depends on the type of pump. Some of the positive displacement pumps like the screw or peristalic types do not need dampeners.

For piston type pumps, it is common to oversized the piping to minimize pumping problems.

 

[micalbrch]

Progressive cavity, gear and lobe pumps do not require a pulsation dampener.

Simplex and duplex piston/plunger/diaphragm pumps must have a pulsation dampener.

Triplex pump should have a a pulsation dampener.

Quintuplex and more do not need a pulsation dampener.

Peristaltic pumps often must have a pulsation dampener.

Tell us what the flow and the pressure is.

 

[ChemEngSquirrel]

Thanks for responses so far. Pump is an air driven diaphragm pump with 3barg discharge pressure and 40litres/hr rate. Line is 8mm internal diameter. Is a pulsation damper required?

Thanks.

 

[bimr]

Not really. You have such low velocity that a pulsation dampener will not be necessary.

Use a hose with a smooth interior, not a ribbed hose. The ribbed hose has significantly higher head loss.

 

[micalbrch]

I agree with bimr. The pump is pretty small and the pressure not very high. Try it without dampener.

 

[ione]

I'm with bimr too.

Take a glance to this, it could help in the future

http://www.pump-zone.com/articles/225.pdf

 

[ChemEngSquirrel]

Thanks all. Good help.

 

[EngAzat]

Hi ChemEngSquirrel,
In my opinion installing a vessel (accumulator)in the discharge line will act as a damper.
Good luck

 

[DubMac]

Positive displacement pumps are divided into 2 classes: rotary and reciprocating.

Rotary P.D. pumps such as screw, progressive cavity, lobe, peristaltic, gear pumps emit almost no pulsations, therefore do not require dampeners.

Reciprocating P.D. pump such as piston, plunger, axial piston, diaphragm,etc. transfer the rotational motion of the driver into back and forth motion in the fluid end. The more pistons/fluid compartments there are, the smaller the pulsation is from each.

As prior posters said, the answer to your question is dependent upon the individual service and installation. If your system is robust enough to withstand pulsations, then don't use a dampener. If the pipes start shaking bolts loose, then use one.

Pulsations will not hurt the pump, only the system or process.

 

[micalbrch]

I have to comment your post DuMmac, as I think you are not completely correct.

Pulsations can hurt the pump too as the pulsations also act backwards to the pump itself.

Peristaltic pumps are rotating pumps but due to their design with one or two shoes which squeeze the hose they can be seen as a simplex single or double acting piston pump as far as it concerns the pulsations. They often need a pulsation dampener.

 

[DubMac]

micalbrch,

You are correct sir; yes some rotaries can require dampeners. Mine was mostly a general statement and is not absolute; maybe just 90% of the time.

But you dont have to call me DuMmac over the deal, come on man, it is Friday after all. This could drive me to drink; and very soon I might add.....

 

[micalbrch]

Yes, sorry DubMac! But as you wrote it was Friday evening....

 

[ports394]

Well.. if backflow was a concern. AODD pumps have check valves.. wouldn't that be sufficient to stop the pulses from acting backwards on the pump?