Filters and Strainers

Filters and strainers are used to separate solids from a process flow for subsequent further processing or to free a process flow from impurities. The pressure losses occurring across filters and strainers depend, among other things, on the load level and can therefore vary significantly. In order to prevent damage to components downstream of filters and strainers, for which there is a minimum required operating pressure, monitoring of the pressure loss might be necessary so that protective measures can be initiated in case of excessively high values.

Cleaning

Filters and strainers are cleaned from collected impurities either at predefined intervals or as needed. The need for cleaning is usually determined by monitoring the pressure losses, as these increase with increasing load level of the filters and strainers. The cleaning is subsequently either done manually or by automated procedures.

Flow Rate and Pressure Losses

As with valves, the dependency between flow rate and pressure losses is expressed by the Kvs‑value. Usually, the Kvs‑value is given for the clean state where filter or strainer are free from solids. As solids accumulate, the Kvs‑value decreases.