Take a look at "screen changers" and "breaker plates". It should give you some ideas and vendors to contact to progress your idea.

Good luck,
Latexman

To a ChE, the glass is always full - 1/2 air and 1/2 water.

I agree - solve the first issue - i.e. trap the debris in something that is designed to be cleaned so you don't get the problem.

If its a return line this implies it's already been through some pumps and exchangers?? surely better to remove the stuff before it gets into the plant?

"If we open partially, the material will be flushed out " - Errrr how does that work exactly?

A drawing or sketch would prove useful.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

Latexman and little " ,

It's sometimes really a problem, the seed goes through the stainer and grows in the linesystem,
the only thing that helps is poison to prvent growing of the shells.
Patibar, plastics and other non-living stuff can be held of course by a strainer.

How about other options than a multi hole orifice plate?

Perhaps a section of smaller diameter line which can't get blocked,

A control valve which can open to max and then close again? something like this http://www.samsoncontrols.com/product/kzt-ceramic-...

look for "V control ball valves". Basically it does your "open the orifice then close it" trick. Whether anyone makes one big enough I don't know, but you won't get much better than that IMHO.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

The best solution could be to install a rotary multi-hole plate that may change the opening angle. It's the same as a butterfly valve with the disc drilled with holes.
I designed and installed this device in the fire water system of a nuclear power plant. See my paper "Eliminate cavitation in your piping systems" published in the magazine HYDROCARBON PROCESSING in February 2012.
It has a cavitation coefficient lower than the multi-hole plates fixed in a vertical position, so probably you may substitute your 2 present multi-hole plates by only one rotary multi-hole plate. Turning the plate it is self cleaning by the flow stream.

Dear Mr. Casflo,

Thanks for your input. Actually we are looking for it only.
I would request you to provide the vendor details.

We need to provide a differential pressure of 4 Kg/cm². Can it be possible with a single rotary multi hole orifice? More over is possible to install a 72" valve since our line is of 72" and flow rate is 13000 m³/h. You said you did the design? What was the situation demanded for such orifice? what is the fluid handled sea water only?

I have gone through your article. it was really good and innovative.

I think that it's possible to install a single rotary multi-hole orifice of 72" to provoke a pressure drop of 4 kg/cm2 without cavitation.
In the case of the article the size is 4" and it provokes a pressure drop of more than 9 kg/cm2 to handle 100/125 m3/h of water taken from a lake.