Basket strainers and cylinders are widely used range of filters used to separate solids from liquids.

With a well-established design, each filter comprises an assembly of a perforated metal cylinder or cone that supports one or more layers of very fine wire mesh.

To increase their structural strength, the filters can also be manufactured with two perforated cylinders with one or more layers of fine wire mesh sandwiched between them, reducing the open area and so enabling the filtration of very fine impurities.

The filters are inserted in a hollow body (known as a filter housing) in the path of the fluid flow, parallel to the flow, forcing the fluid to pass through the filter media. The size of the wire mesh required depends upon both the type of fluid to be filtered and the size of the impurities.

These types of filters can provide a very high degree of separation with little change in the pressure drop across them. They must be cleaned or backwashed to prevent substance build-up – something which would gradually affect the filters' performance.