A duplex strainer, also known as a twin basket strainer, is a type of filter that is installed in a gas, oil, or water piping system to remove large particles of dirt and debris. In most cases, a duplex strainer system consists of two separate housings for strainer baskets. A valve handle is also included between the two boxes to redirect liquid flow to one strainer while the other is being cleaned.

In some strainers, the valve will operate automatically, and the strainer will perform a self-cleaning method.

These kind of strainers are used in pipeline systems when the flow cannot be stopped. They can filter up to 40 µm depending on the size of their NB. Basket strainers are used in industries where the majority of the pollutants are solids. These strainers, unlike other types of strainers, are very simple to maintain.

Duplex strainer

How Does A Duplex Strainer Work?

A Duplex strainer, or a Basket strainer, is made up of two distinct strainer baskets that are housed together. The suspended solids are trapped in a cleanable basket.
valve handle is put between the two baskets to restrict the flow of liquid to one strainer while the other is being cleaned. Butterfly valves are used to change the flow direction.

Lube oil system uses duplex filters. Only one filter is used at a time, while the other is kept clean.

What Is The Purpose Of a Duplex Strainer?

These strainers or filters are used where the flow of the fluid cannot be stopped. For example in Fuel Lines, Lube Oil lines etc where if the flow is stopped, it can lead to the fatal failure of engines and equipments.

Cleaning Of Duplex Filter

Filters are cleaned on a regular basis or whenever there is a pressure drop. To clean the filter, flip the filter over to the clean side.

Open the purge cock on the filter you’re using and make sure oil is flowing through it.