Pulsation dampener requirement

[VKu]

Getting issue with centrifugal water pump system, starting up of pump causing pressure surge which lead to failure of rupture disc down the line.
Pump data:flow rate 585 gpm
total head 410ft
NPSHa 25 ft
Maximum suction pressure 4.9 psig
Rupture disc set point is 240psig @100 deg F
Can a Pulsation Dampener be a solution to this issue?

 

[BronYrAur]

When you say total head, do the mean the dead-head of the pump - far left of the curve? Or does 410 ft correspond to your flow rate of 585? Does the pump have a soft start or VFD?

 

[LittleInch]

Surge on pump start can be casued by many things.

A pump curve and a schematic of the system is required.

Is there a possibility of drain back or vacuum developing in the system?

A pulsation damper will do very little, but you might need a surge tank, a control valve, a relief valve or a soft start to your motor.

Rupture discs are notorious for not liking shock loading even well below their set pressure.

Is this new or just started?

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[VKu]

Thanks for response!

Total head given correspond to flow rate of 585gpm. Not using soft starter.
This is new pump, working on commissioning of project. Installed control valve to resolve the issue but still getting same problem.

 

[chief]

A pressure surge is caused by an empty pipeline with air in it. The air is compressed as the water begins to flow and creates destructive water hammer effects. Fit a jockey pump ((Low power ,low flow) to maintain a full pipeline and possibly a little circulation line or safety valve to create a small circulation line to prevent overheating of the jockey pump. Do not forget a check valve to prevent backflow on the jockey pump.

Offshore Engineering&Design

 

[georgeverghese]

Dead head pressure of 187psig for the 10.2in impeller is 78% of RD set pressure, which seems ok. Maybe you have the 11.0in impeller (dead head pressure of 222psig = 92% of RD set press, which is too close) ? Also check with the RD vendor if the max operating 187psig is within the max permissible limit for the RD purchased - some cheaper RD designs may not permit max operating pressure exceeding 70-80% of stamped burst pressure.

 

[Latexman]

What RD do you have? Some can take more abuse than others.

Good luck,
Latexman

To a ChE, the glass is always full - 1/2 air and 1/2 water.

 

[BronYrAur]

Is the pipe always full of water, or is it empty until the the pump is energized?

 

[bimr]

ClaVal and Singer manufacturer Pump Control valves are designed for installation on the discharge of a pump to prevent pipeline surges caused by starting or stopping of the pump. These valves usually include check valves as part of the valve.

ClaVal Pump Control Valve

This type of valve will most likely eliminate the problem, or you can look at the pipeline.

As the previous posters noted, the problem originates in the design of the pipeline which you have not described. Do you have more information on the pipeline?

 

[VKu]

its empty

 

[VKu]

Thanks Latexman, I do not have information for RD manufacturer. I may need to check that.

 

[LittleInch]

Vku,

Please stop drip feeding us information one drip at a time if you want us to help you.

you need to provide enough decent information that we can understand your system ( size, length, orientation etc, how the operation worked before, how it operates now as it seems the pump is new, what other things you've tried and didn't work and all other relevant information which has been requested.

Then we as a disparate group of responders may be able to assist you in looking at your problem

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[VKu]

Sorry, It took some time to collect all the informations. See attached sketch of system, Its 2 pumps in parallel, stating one at a time.
Earlier in similar system, but pump with lower hp pump working fine. This time we have bigger pump which is causing this issue. We tried with adding control valve that did not help. Other than that we are think about putting actuator on the ball valve(next to dual plate check valve) also about 'surge absorber or pulsation dampener.
Thanks

 

[VKu]

Thanks bimr for ClaVal control valve suggestion. Considering that option.

 

[bimr]

Hard to understand what your operational process is. From your notes, it appears you are starting the pipe system empty (assume that the piping drains out by gravity).

Based on these observations, the problem would most likely go away if you kept the piping full of liquid.

You might call the local ClaVal representative and have him review some of the options available. CalVal (and Singer) make all kinds of products for these applications such as relief valves and back pressure valves.

relief valve

 

[georgeverghese]

Your sketch shows the RD set at 230psig, while your first post says 240psig. Also check with the pump vendor what is the tolerance on actual developed head when compared to published curves - the pump may actually be developing a slightly higher head than the standard published curve for a given impeller size. You may want to post us the design case spec RD datasheet and the vendor supplied RD datasheet if you need help.

 

[chief]

To prevent air accumulation in the system pipelines ,fit an automatic air vent at the highest system point. As previously mentioned the system can be maintained full and pressured by the use of a jockey pump set to cut-in/out by a pressure switch arrangement.

Offshore Engineering&Design

 

[LittleInch]

Looking at your system, I'm still surprised you have a RD there. Normally RD are used where there is either some dangerous or very hazardous fluid and you don't want any leakage passed a relief valve or where the pressure rise is very fast such that a relief valve won't open fast enough ( e.g. LP shell side of a HP HX).

Your check valve appears to be shown the wrong way around?, but if your system is empty you could be running a long way to the right of the curve on start up and hitting > 1000gpm down the line. That would result in a fairly big surge when it finally hits some end point.

An update would be appreciated.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.