Duplex strainer or twin basket strainer is a type of filter built into a fuel, oil or water piping system and it is used to remove large particles of dirt and debris. The duplex Filter system usually consists of two separate strainer baskets housed. The system also contains a valve handle placed between the two baskets to divert the flow of liquid to one strainer while the other is being cleaned. On some strainers, the valve will work automatically and the strainer will perform a self-cleaning operation.

These types of strainers are installed in the pipeline systems where flow cannot be stopped. Depending upon their NB size they are capable of filtration up to 40 µm. Basket Strainers find use in industries where impurities are mostly solids. Unlike other types of strainers, it is easy to conduct maintenance on these strainers

Duplex Filter are mainly used in various industries such as process industry, power industry, chemical industry, oil and gas industry, pulp and paper industry, pharmaceutical industry, metals and mining industry, water and waste management, fire fighting industry, refineries and petrochemical plants. Strainers are used to remove hazardous elements that might cause partial or complete breakdown of operations if they get into the system.

Duplex Filter is used to fluid filtration from impurities. This equipment consists of two vessels with needed filters. The isolating lines will be handling with butterfly or 3-way valve. The filters of duplex filter are washable. The standard that usual for vessel drawing Is ASME.