An inline filter or screen is essentially a piece of wire mesh inside a housing. In your home pressure system, this simple piece of equipment sits after the pump and before any other filters. Its job is to catch any debris which would otherwise end up blocking your more expensive cartridge filters. The beauty of the inline filter is it can easily be removed by the home owner, washed under the hose and put back in place. This is one of the ways you can ensure your cartridge filters last longer and can do the job you require them to do.
*NB Placing inline filters or screens before the pump means that if the screen becomes blocked it can cause the pump to keep running even when there is no water flow – putting undue pressure on the pump and potentially causing burn out.