Pulsation Dampener Charge Indication 1

[sshep]

My Friends,

One of our plants uses alot of milton roy hydraulically actuated diaphram pumps for process service. There have been a number of cases where the pulsation dampeners lose their charge, causing problems and equipment failures. Our maintenance department wants to put in some way to monitor the health of these pulsation dampeners when they are on-line. Pressure does not seem a useful indication because it will simply float around the process pressure.

Is there some model of pulsation dampener which has a travel indication to show the compression of the bladder, (or diaphram, or bellows as applicable)? This seems like something that might exist. Otherwise I will take any advice on an alternative.

best wishes,
sshep

 

[micalbrch]

That is a bit strange. You talk about bladder/diaphragm type dampeners and not about air-over-liquid dampeners, correct? If yes, why do they lose charging pressure? Do you use compressed air for charging or pure nitrogen? Some manufactures specify nitrogen only as oxygen molecules can pass the bladder so that the dampeners lose charging pressure. That can be a reason.

I have head of manufactures who manufacture self regulating dampeners. ABEL pumps is one but as far as I know they do it for high pressure (> 600 psi) only and these units are rather expensive and require a permanent compressed air connection. They monitor the movement of the diaphragm but don't ask me how. I suppose they work well but that does not help you with your existing units.

 

[sshep]

Thanks. Your link to Abel was exactly what I would expect from a system which could monitor and charge itself. I can see some benifits for systems which might pump against a wide range of process pressures.

Our dampeners are charged with N2 from a bottle. The whole inquiry comes from some instances where the charge got low. There are a few threaded connections which could leak- fill valve, pressure gage, etc. I also made the comment that we should soap test as part of a regular fixed interval maintenance program. At places I worked previously this was like an every 3 or 6 month type thing because there should not be any leakage. I should probably make some observations on how we are filling these things- it could be an operator thing. Maybe some don't depressurize before charging or something simple.

An "air over liquid" system would allow for monitoring, but such systems have their own problems. Personally I don't see why someone hasn't invented a system that uses a spring which would effectively not require any attention at all once set to the right tension.

best wishes,
sshep

 

[micalbrch]

I think your idea to check filling valves and gauge connection is the best idea. As you use the correct gas, I cannot see any other possible reason than leakage through the fittings.

Yes, your idea with the spring sounds good. But keep in mind that most probably not the manufacturer but the operator must set the spring. That is the first problem (guarantee). The second is that you would need gas in any case to support the diaphragm. And last but not least such a dampener is a pressure vessel. Whatever is done with it must be approved. I think that's why nobody did it so far.