Strainer or No Strainer? Both schools of thought have their strong points

摘要

For years, members of the back- flow prevention industry have debated the value of strainers at the inlet of an assembly's installation. Arguments on both sides of the issue have merit and should be carefully considered before a strainer is installed. A strainer is essentially a screen placed in the flow path. It is intended to catch sand and debris that may foul the integrity of a check valve. A fouled inlet check valve in a reduced pressure principle assembly, for example, will cause the relief valve to discharge intermittently with small sand and potentially several gallons per minute with lunch buckets and two-by-four sized debris.