frl unit (filter-regulator-lubricator unit)

FRL UNIT (FILTER-REGULATOR-LUBRICATOR UNIT)

• In most pneumatic systems, the compressed air is first filtered and then regulated to the specific pressure and made to pass through a lubricator for lubricating the oil. Thus usually a filter, regulator, and lubricator are placed in the inlet line to each air circuit. These may be installed as separate units, but more often they are used in the form of a combined unit.

• The combination of filter, regular, and lubricator is often labelled as FRL unit or service unit.

• Fig.11.11 illustrates the arrangement of a FRL unit.

• Composite symbol: Fig.11.12 illustrates how individual component symbols form a composite symbol of a FRL unit.

1. Selection of a FRL Unit

While selecting a FRL unit, the following factors should be taken into account.

1. Consideration of industrial environment:

• For tough industrial environments (such as foundries, shipyards, oil & gas and heavy machinery), use of metallic FRL is recommended.

• For small industries (such as vehicle service environments), composite FRL would be a better choice.

2. Air flow requirement of the tool: It is always recommended to select an FRL unit with an air flow capacity superior to the tools requirement.

3. Pressure drop in the system: Pressure drop is the drop in air pressure from the beginning of a pipe to its end. Based on the amount of pressure drop, appropriate FRL unit will be selected.