1 reply to this topic

[a1986]

Dear Sirs

i have received some process data sheet for gear pumps. i have notice that in three of ten data sheets is not expressed at what pressure is set internal relief valve...

 

in your opinion why is not defined set value for internal relief valve of this three pumps??

is this a value that process have to indicate? do i ask for this value at my process department??

 

best regards

[Art Montemayor]

  

Never rely on the effective performance of an internal gear pump pressure relief device.  What I mean by this is that you have no documentation to prove to safety authorities that the device is appropriate and dependable for safely relieving the pump.  That doesn’t mean that the device is flawed.  It just means that the pump manufacturer is not in the business of designing and studying relief devices.

 

What I am recommending to you is backed up by practically all the major chemical and petrochemical companies in the world.  When I worked DuPont projects, we would strip the gear pumps of these devices and specify and install custom, specific relief valves that were fully documented to do the specific job – and we would never discharge the relieved liquid back to the pump’s suction; we would pipe the discharge back to the source tank or vessel.

 

I don’t know who you are and what your position is in your company, but I would surely work with the process engineer who is responsible for specifying the subject pump and ensure that the data sheets clearly indicate what I have stated above.  I can assure you that the pump manufacturer will not be able to give you specifics (like Cv, relief rates, etc.) regarding their internal relief device and will be only too glad to allow you to furnish a separate, designed, pressure relief valve.