Strainers are extensively used to trap foreign materials from different major rotary equipments mainly like pumps, compressors, fans, blowers etc or it may be used for protection of major instruments like meters, valves, and seals.
These are mainly neglected piece of equipment which are mainly important not only for protection but are MUST for many services and many chemical processes can not run without them. Still we do not focus on use of suitable design of these strainers.
Its a closed housing with cleanable screen element designed to remove & capture foreign particles.
Strainers are called strainers because they are used to strain or filter out debris / particles from liquid streams. They basically have one housing and one filter element nothing more than this. The discharge port is usually the intermittent outlet from it.
The main function of these strainers is to capture all particles above design specs reliably & in an uninterrupted manner with very little maintenance ans spare parts.
Currently the wedge wire construction of filter screen is very effective for all strainer applications. The advantage of wedge wire usage in any filter application is that it is non-clogging in nature as it is hard steel mesh of V-Shape in place of cloth and hence there is no pores choking during any sticky or slimy application.
Now the salient feature of a good strainer is that
1. It should have sufficient operation time before choking or clogging. Use wedge wire mesh for easy online cleaning.
2. Easily back washable. Wedge wire system can be easily washed online (in place with just one back flow). In case of cloth etc it has to be opened and closed after manual cleaning. So it actually becomes CIP filter easily.
3. It should pose minimum pressure drop in the system which is possible with wedge wire very easily.
4. long life span.
5. Wedge wire based Duplex system can be a very good option for continuous operation in non acidic media.
6. The only disadvantage of wedge wire is that currently we don't have any option to have it in nonmetallic MOC. I mean if nonmetallic MOC is required wedge wire is not possible today.
In next article, I will post about selection of strainers.