Basket strainers are installed to protect equipment from damage caused by unwanted debris that may be in the pipeline. The unwanted debris could be dirt or other foreign particles that make their way into the process fluid. From here, they can really make key liquids a great deal cleaner and to some degree, more hygienic too. They can make no end of a difference to the end user.
What you need to know
Basket strainers are a device typically connected to a pumps suction. They are a device in turn which is used to filter out solids. Or debris larger than the mesh contained within the strainer, which would otherwise damage the pump, internal parts or system. They are used to capture particles which are usually visible to the naked eye, and if smaller, filters are typically used.
The design of self-cleaning basket strainers
Self cleaning strainers, also known as backwash filters or automatic strainers consist of a strainer, drain, scraper and motor. Within the strainer there is a hollow shaft with a blade which when the cleaning process is initiated, scrapes along the inside of the mesh removing debris. Simultaneously a bottom outlet valve opens creating an area of low pressure causing the recently freed debris to flow via the bottom outlet valve and be drained away.
The cleaning process is initiated either by a timer. It starts the motor located at the top of the unit to begin the screening process. Or via a differential pressure switch which senses when the screen is blocked. Pressure switches are located on the inlet and outlet of the unit and when the inlet pressure is higher than the outlet pressure, the filter is known to be blocked. These are low maintenance designs enabling the mesh to remain clean and free from solids. Also with long maintenance intervals, without manual intervention.
Overall
Installing a basket strainer into a pipeline system ensures that equipment downstream is protected from unwanted and potentially damaging debris. Choose a mesh size slightly smaller than the particles you wish to filter. Do so to ensure that any foreign particles are trapped in the basket. You’ll also want to consider other factors, like the temperature and pressure requirements. Also think about the type of liquid or gas passing through the basket strainer. Be sure to maintain your basket strainer by checking pressure periodically. Also you can do this too by scheduling regular cleanings as well. This small investment will have lasting impact on downstream equipment.
