How much time is recommended to maintain the suction strainers in a new crude oil instalation (in the suction piping line before the centrifugal pumps)?
Seriously, If you plan to leave the strainer in, install pressure taps so you can measure the delta P and know if it is clogged.
If you are really confident that you've done a good job of cleaning pipe, you can go without the pressure taps and remove the screen at your earliest opportunity after startup.
We've run years with some of these screens in place. At 200 percent area, pressure drop isn't a problem unless they clog, which is of course why they are there in the first place !
If we are taking about startup strainers (Royal Knight,cone type,etc); these suction strainers are normally used for equipment startup only; sometimes they are removed after water flushing operations and before actual production. If they are kept in place they need constant attention. If continued filtration is required, a filter designed for continuous service is recommended.
I'd agree with CHD01, if you want permanent filtration, install filters, in my experience suction strainers are put in to catch welding slag, loose nuts, bolts, welding rods, etc. that might have been left in pipe from construction during commissioning. I'd expect them to be pulled after commissioning and prior to normal operation.
A Diferential Pressure meter would be good idea, filters in the suction lines can cause pump cavitation.
Whenever you suspect the entrance of dirt, use a strainer. If you are pumping from a tank you might catch some rags.
If you are using foam pigs to clean your pipe lines, be sure to mount a strainer in the suction.
Whenever pumps start cavitating, is noisy or vibrating heavily, check the strainer first.
