Pneumatic FRL (Filter, Regulator & Lubricator) unit - How They Work
The FRL unit is always located at the air inlet of the plant. It is used for purifying and treating the compressed air. This unit consists of the following components:
These components you can also find within the detailed symbol.
The unit usually includes a pressure regulator with gauge (manometer). Since the pressure in the following sections of the plant only can be below the central system pressure, it is also called a "pressure reducer".
A fine-pored filter is used to purify the compressed air of dirt, pipe sinter from the distribution network and condensate.
An lubricator adds to the compressed air an oil mist. Oil can reduce the wear of an installation. However, if the compressed air has been lubricated once, it has to be oiled constantly , as the old oil hardens. Since the materials are getting better, newer plants can avoid oiling.