Application mandates a strainer, not aware of any standard regulating a strainer.
It is a capital mistake to theorise before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts. (Sherlock Holmes - A Scandal in Bohemia.)
Although it is not in a specific code, it is general good industry practice to include a temporary start-up strainer in pump suction lines. You can find such references in API 686 "RP for Machinery Installation and Installation Design." Go to chapter 6 "Piping", section 2.8 "Inlet Strainers". There is information on both permanent and temporary inlet strainers in there for you.
You need them to ensure that your pump is protected during start-up from any sort of construction debris, trash, slag, gloves, tools, animals, etc., that may have been left inside of the piping. Although I've never specifically had an issue with this, I've heard many stories where such items were left inside of the pipe and not captured until it was too late. One situation that sticks out involved an entire side grinder left inside. Wasn't a good day for them from what I'm told.
As RVAmeche stated, most pump manufacturer's also state/recommend the need for one in their technical documentation as well.
"Thinking is the hardest work there is, which is probably the reason why so few engage in it."
Dear all, thank you for your response. it is so helpful.
Dear MrDGrayPPD, Your answer about start up activity that makes me initiate this question. in one of my project case, a strainer installed on pump suction with 60 mesh and it result so many debris which is we have to clean it very often. My question is what parameter of pump that can decide which mesh size should we use?
The pump manufacturer should provide a value for the maximum sphere size that the pump can pass. I prefer to let the pump pass small particles rather than have them accumulate in a strainer that needs to be cleaned and which can damage the pump due to cavitation. If the pump could pass a 1/2 inch sphere, I see no need to capture particles any smaller than 1/4 inch.
If the inlet is coming from a tank or something where you have low NPSH margin (5-10m say), then strainers can cause more pump damage from cavitation as they block up than they save from the odd bit of grit wandering through the pump.
The worst are simple top hat type strainers installed for commissioning which never get removed or take hours to dismantle pipework to get it out.
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
Suppose that the "temporary" strainer is used on the pump suction during the start-up. Per experience, it may need to dump out the debris several times if too much junk in the pump suction pipe during start-up. After then, the temporary strainer may be removed.
The issue from the OP is that he's got a 60 mesh filter on what seems to be a fairly dirty service.
Now for me either clean up the service or fit in a "bolt catcher" with 5mm or 10mm holes and let the pump flush through the much smaller sand / grit particles.
A 60 mesh is 0.25mm
Or install a self cleaning filter / cyclone
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
Dear all, thank you so much with all the responses.
I have study case when a centrifugal pump with duty as Deisohexanizer Reboiler Pumps, it flows treated naphta from bottom product of Deisohexanizer to a Furnace and it circulating so on. My question has the same topic which is permanent strainer used on pump suction has 60 mesh. it is stated on data sheet that permanent strainer size is 60 mesh. Why is that? what is vendor/pump supplier consideration to pick so finer mesh of strainer?
If the pump is a canned motor pump, not designed to pass solids of any significant size, a permanently installed strainer might be recommended by the manufacturer. But, I don't see any details provided for the type of pump. But, if there are significant solids in this stream, a canned motor pump should not have been selected.
From experience, I would have a strainer anytime.
Just need to be concern with the mesh size so that it does not impede flow.
As a maintenance engineer, and worked on many pipe repair on the upstream of the pump, you'll be surprised on the amount of crap left in the pipe after repair work.
Like rags, consumables, etc.
Luckily they were mostly captured in the strainer.
What unit are we operating here ? Is this de iC6 column downstream of a platformer / CCR? There are numerous cases of pumps and other equipment fouling up in these and similar units where chlorides are used to maintain catalyst activity - overdosing the chloride activator at the feed inlet to the platformer is the root cause of these fouling issues.
