It is inevitable that imnpurities will make their way into the aire distribution lines in any system. Pipe scale, rust, moisture, compressor oil, pipe compound and dirt are some fo the contaminates that can damage valve parts and other close fitting parts of downstream devices.
A filer will remove all foreign matter and allow clean dry aire to flow freely. It should be installed in the line upstream from all working devices and in such a way that it cannot be bypassed to avoid damage to those devices.
The filter capacity should be large enough to handle the required flow of air. in order to properly size a filter for a particular application, the maximum allowable pressure drop that can be caused by the filter should be established.