What is an FRL and How Is It Important to a Pneumatic System and Its Components?

Posted June 27, 2018

Pneumatic systems are incredibly useful, allowing you to power all of your tools and devices. But like any system, there are key components that must be utilized to protect the system and the tools running off of that system. The FRL, or filter regulator lubricator, is one of these components. The FRL allows you to account for the heat, moisture and dirt that are inherent in compressed air.

The Three Components of a FRL: Filter, Regulator, Lubricator

The FRL packs the three things you need inline, ensuring that the air coming out the end is exactly how you need it to be. Let’s look at each component:

Filter

As the name indicates, the filter is there to clean contaminants out of the air in the line. As with most filters, it acts as a strainer, allowing air to flow through while trapping dirt, rust, dust, etc. The filter also separates liquids into oil and water. The filter is the first stage of the FRL system, installed upstream of both the regulator and the lubricator.

You are probably well aware of how damaging contaminants can be in your pneumatic system. The dirt and other particles have to go somewhere, and they do—straight into whatever piece of equipment is using the air. The contaminants gum up your tools and increase friction, eventually leading to loss of functionality or complete breakage. The more you can filter out such contaminants and keep them out of your equipment, the less downtime you will have to deal with.

Downtime is expensive, so it pays to have the best filter you can find in your FRL. You can choose from three different filter types—general purpose, vapor and coalesce. General purpose filters can remove both particles and liquids. Vapor filters catch odor and oil vapor. Coalescing filters take out oil.

Keep in mind that filters will create a drop in pressure, so you need a filter that will get the job done without sacrificing too much pressure.

Regulator

The regulator serves to maintain pressure at a level that is right for your system. They can reduce pressure coming into the system upstream while seeking to maintain constant flow downstream. Ideally the regulator should keep perfect constant pressure, but in reality, it will always be affected by what is occurring upstream.

There are two main types of general purpose regulators—relieving and non-relieving. The relieving type can let the pressure off the system as necessary. The hissing noise you hear from pneumatic systems is the sound of this type relieving the system. A non-relieving type will not do this. With non-relieving regulators, you need another method of relieving the system.

A regulator should be chosen based on what kind of pressure and flow requirements you have for your equipment.

Lubricator

The majority of tools used with pneumatic systems require lubrication to operate efficiently and to minimize wear and tear from internal friction. While it is sometimes possible to lubricate these tools using a grease gun or other method, it is usually less messy and more effective to lubricate them through the airflow. A lubricator in a FRL system lets you add a precise level of lubricant to avoid over-saturating your tools.

The oil added has an added benefit—it can clear out undesirable oils from the system, such as those from the compressor.

You have two options: either oil-fog or micro-fog. Oil-fog delivers larger drops to the airflow, while micro-fog delivers much smaller drops to form a mist.