HD30, HD40, HD50, HQD30, HQD40, HQD50, HQD75, HQD120, P185, P420 Oil Filter Element

Purpose of an Air Compressor Oil Filter

An oil filter is crucial in air compressors, particularly in larger systems like oil-injected screw compressors. It helps:

• Remove contaminants: Filters out dirt, sand, rust, and other debris from the oil, preventing these particles from causing wear on bearings, clogging the oil separator, or damaging the compressor.
• Prevent excessive wear: Ensures that only clean oil circulates within the system, extending the life of the compressor and reducing the need for repairs.

Components and Design

Most air compressor oil filters resemble a can with an opening on one side. Inside, they contain a folded paper element designed to maximize surface area and allow ample oil flow. However, not all filters are identical, and quality variations can significantly impact performance.

Types and Considerations

1. Bypass-Valve Feature

   • A critical feature, especially in rotary screw compressors, is the bypass valve. This valve opens if the filter becomes clogged or the oil is too cold, allowing oil to flow around the filter.
   • This feature ensures that the compressor always receives oil, as operating without it would lead to overheating and potential damage. Lower-quality filters may lack a bypass valve or have one that activates at incorrect pressures.

2. Temperature Resistance

   • Unlike automotive filters, air compressor oil filters are designed to withstand higher temperatures, often required by synthetic compressor oils. Using an automotive filter can lead to issues due to inadequate heat resistance.

3. Oil-Free Compressors

   • Even some oil-free rotary screw compressors have oil filters, specifically for the gearbox oil. These filters clean the oil used to lubricate the gearbox, which houses the motor and compressor elements.

4. Reciprocating Compressors

   • Smaller reciprocating compressors generally lack oil filters because they rely on the crankshaft splashing oil to lubricate components. Here, regular oil replacement is essential to remove contaminants.

Choosing the Right Filter

When purchasing a filter:

• Ensure it has a properly functioning bypass valve.
• Check its compatibility with synthetic oils and high-temperature applications.
• Avoid automotive filters, as they may not meet the specific demands of air compressors.