Strainers are mechanical devices to retain (and remove) foreign particles from flowing liquids and protect equipment such as pumps and compressors. There are several types of strainers, including the Y, basket and duplex types. A critical element is the strainer’s screen, specifically its mesh size (perforation density).
PIPE STRAINERS TYPES
There are two basic designs for pipe strainers, i.e. “y-strainers” and “basket strainers”.
A Y-strainer has a y-shaped compact design and is used to capture foreign particles flowing through the pipes of a pipeline.
Y strainers can be installed either horizontally or vertically, with the filtering element positioned towards the ground, and generate a pressure drop in the pipeline.
This type of strainer for pipeline needs to be cleaned often, to make sure that the filtering ability of the device is not jeopardized by the accumulation of debris. The pipeline can be kept in service, generally, when y-strainers need a cleanup.
Y-strainers suit high-pressure gas pipelines with a low concentration of foreign particles and debris. Indeed, Y strainers have a lower capacity to store dirt than basket strainers of similar size.
BASKET STRAINER (T-STRAINER)
A basket strainer features an upright and perforated basket that traps the foreign particles carried by the fluid conveyed by the pipeline.
A basket strainer can store bigger quantities of dirt and debris than y-strainers of the same size, due to the larger size of the filtering element, and is the preferred choice when pressure drops in the pipeline are not acceptable.
T strainers shall be installed upright, and the top of the strainer can be removed for frequent cleaning (self-cleaning t-strainers are also available on the market).
A special type of T-strainer is the so-called “duplex basket strainer”: this device, consisting of two parallel basket strainers, facilitates the maintenance of the filtration element keeping the line in service (the line is bypassed when one of the two strainers is cleaned).