Finer mesh for pd pumps, coarser mesh for centrifugals. Y type strainers for lighter duties ( low dirt holding capability for Y type). Basket strainers for more dirt holding capability in moderate to heavily dirt laden liquid streams.
Presume this post is related to your other recent post on pump shaft leakage on a centrifugal. One way to resolve would be as you have discovered ie to install a finer mesh strainer to filter out finer particles in the entire feed stream. The other way is to modify the seal flush plan to enable finer filtration/screening of the seal flush stream only - talk to your rotating machinery specialist colleague on the relevant API mechanical seal flush plan identifier (plan 31 I gather from the internet ?). This may be a better solution if this seal flush plan can be implemented.
I was not asked. However please can you elaborate more what parameters are needed? I would like to know what parameters are required upon which mesh selection is dependent. I did not ask to select mesh or did not ask that mesh needs to be replaced with more appropriate one
there is no direct answer to your question. You really need to ask or look at the technical data from the pump or seal vendor as to what they recommend. You may only get some good information if you talk to them as they may not want to write it down due to liability.
Too small a mesh and your operators will be cursing you as the filters might need cleaning several times a shift and cause disruption / shutdown etc and then all that happens is someone either changes the spec of the filter or "accidentally" increases the size of the holes in a non approved manner.
It can also lead to pump damage if your inlet pressure falls below the NPSH / cavitation of the pump.
SO
first and foremost find out what size particles cause you an issue in your d/s equipment
Then work out if you have enough inlet pressure not to kill your pump. Normally clean filters are 2-3 psi DP, dirty one up to 12-15 psi DP
Then also try and work out if possible what the particle load is in your incoming fluid (may not be possible)
Is there anyway you can do a trial on similar fluid to see how much dirt you collect at different mesh sizes?
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
Thanks. For such great reply. No I dnt have any facility to do trial.. what do you mean by 2-3 psi DP? PLEASE EXPLAIN
Also, is there any chart available which can be filled and submitted so as to acquire accurate meah size? I can test products in my laboratory to get parameters like solid particles etc.
2 to 3 psi differential pressure across the filter.
If your inlet is coming from atmospheric tanks you might not have a lot of spare pressure to drive the fluid through a filter. We know NOTHING about your system as you haven't told us anything.
A simple search for filter mesh size gives you data like this.
Thanks for reply. The link is very useful but I want to know what factors are needed to select mesh like if I give inlet pressure temperature solid particles fluid composition etc then thw mesh can be selected appropriate to the service of the pump and associated mechanical seal.
Hope you get my point.
I get your point, but there is no simple response.
Filter mesh type baskets are intended to be used to prevent the passage of particles bigger than the hole size in the mesh. How big that hole is is up to you depending on the cleanliness requirement of the downstream equipment.
The bigger issue then is how much material will be collected and how often the filters will block up to create a differential pressure greater than 12-15 psi. That's not easy without some sort of actual practice or understanding of the amount of material likely to be caught by the filter.
If the fluid can be described as "clean" then a filter mesh is probably the right move. Anything else including occasional "dirty" batches or where you can calculate from samples and testing that X,000m3 of product = say 2 kg of particles. If X,000m3 equates to less than 7 days operation then you might need to look at more complex filtration systems such as cyclones, self cleaning filters etc.
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
