The Operating Principle
Straining
As raw water enters the unit, it passes through the tubesheet into the ports of the multiple Poro-Edge™ strainer tubes, causing dirt and debris to collect along the length of the tube. The tubes retain any solids while allowing clean water to pass through the slots and into the strained water chamber where it exits via the outlet.
The strainer operates continually with only a 2 PSIG pressure drop until the filter media are seventy five percent (75%) full of dirt
Unlike other strainer designs, the tubesheet is the reason for the 2 PSIG pressure drop, not the filter media.
As the strainer continues to collect the dirt beyond the 75% full condition, the pressure drop begins to increase.
At 4 PSIG, the strainer goes into backwash mode.
Backwashing
During backwashing the stainless steel backwash assembly rotates along the tubesheet. The seal plate forms a pressure tight connection with the tubesheet permitting each tube to be cleaned – one at a time – in consecutive order.
Unlike other designs, the Poro-Edge media of the R.P. Adams Strainer is separated from the backwash mechanism by a substantial metal tube sheet. This prevents the backwash mechanism from coming into contact with the media and damaging the elements caused by large solids becoming lodged between the media and the backwash arm. In the event of the shear key failing, due to very large solids entering the raw water chamber, the large surface area of the Poro-Edge media will permit flow to continue, allowing time to correct the problem before a loss of flow is encountered.
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