Temporary strainer selection

[lokmane]

Hi,
What are the selection criteria for a temporary strainer to use during the commissioning? I think this has to start by defining the particle size any suggestion on this?
Second thing if the equipment is fitted with a operation strainer do I need to add a temporary one?

And thanks in advance.

 

[LittleInch]

What ever particle size would damage the downstream equipment.

You need to look at this as a permanent arrangement and make sure you have differential pressure being monitored and some relatively easy way of getting the thing out without breaking lots of flanges. Now I would actually install a filter body, maybe a Y strainer and then just remove the basket after commissioning. Once you've removed all the pipe to get your strainer out and then re levelled everything, you would save the money by fitting a proper body in the first place....

Make sure it's good and strong - last one I put in had 20 bar (sic) across it and had bolts, bits of weld cut outs, sand, paper, gloves, and assorted welding rod ends etc in it. Fortunately we had made it out of 3mm Stl Stl and the end bowed a bit, but it didn't break up. If your temporary strainer blocks and then breaks this is worse than if it wasn't there it the first place.... The previous strainer we rejected looked like a waste paper bin and was made of v thin mesh - this wouldn't have lasted a minute.

These guys are great for bespoke stuff and know what they are doing and dispatch world wide.

http://www.filters.co.uk/

My motto: Learn something new every day

Also: There's usually a good reason why everyone does it that way

 

[lokmane]

Thank you Littleinch for your valuable input, you had used 3mm strainer, based on what you had choose this size? is there a selection guideline because i believe that if we select a small size this will plug rapidly, and larger one will not protect downstream equipment
Regards.

 

[LittleInch]

I used a 3mm thick punched hole body but with an 80 mesh insert inside it. Sorry if I confused things.

As I said, it is a balance between initially regularly plugging the filters and damaging the downstream equipment. Normally you see these filters directly u/s of things like compressors, HX's and other equipment which can be damaged by dust and dirt but in normal operation filters further u/s take care of it. However during commissioning the pipework etc in between can be full of dust and debris. You still need to protect your d/s equipment to the same level as you would in normal operation - that requirement doesn't change. If you end up damaging a $20MM compressor for the sake of a $10K filter which was too big then no one is going to thank you....

Cleaning commissioning strainers which need pipework to be dismantled each time is a real pain, especially if it's finely balanced and supported which is why I would now recommend using a solid filter body which you can access the internals much easier and then for normal use either remove the filter element / cage or replace it with a "bolt catcher" where you could just have say a 5mm hole in the filter cage to catch any big thing which gets introduced during maintenance etc.

If your commissioning filter starts clogging then it is doing its job(!)

My motto: Learn something new every day

Also: There's usually a good reason why everyone does it that way

 

[lokmane]

Thank you for your help.