Intake filters for compressors: the air filter on the inlet

Intake filters

The intake filter is the first thing a compressor breathes through. Dust, sawdust and pollen behave inside the cylinder like grinding paste — without filtration they wear the piston rings and the pump seizes. A clogged filter is almost as bad: the machine chokes on it, takes longer to fill, and burns more electricity than it needs to. We carry original filters for ATMOS, ABAC and Black Wind as well as universal metal ones with threads from 3/8" to 1".

First, let us settle which filter you are after

The phrase "filter for a compressor" means two entirely different things, and it is worth not mixing them up. The intake filter — the kind in this category — sits on the inlet and protects the machine itself from workshop dust. It is a cheap part that gets changed regularly.

If what you need is clean air at the outlet — free of water, oil and dust, for spraying or for air tools — then you are after filtration downstream of the compressor. That lives in compressed air treatment, and our article goes through it in detail. An intake filter will not help you at the outlet, and the other way round.

The whole filter, or just the cartridge?

This is the question that comes up most often here. What decides it is the state of the housing — the shell the cartridge sits in.

What they look like

A complete filter is the housing with the cartridge in it, and it screws into the inlet. The cartridge is only the inner part.

Which filter belongs on your machine

The Counterpart column says what to order instead of the whole thing, or alongside it: for a complete filter that is its cartridge, for a cartridge the filter it belongs in. The thread is given wherever the source states one — filters tied to a particular pump are not chosen by thread but by the machine.

#showmore#

When to change the filter

How often

Normally once a year, or together with an oil change. In a dusty shop considerably more often — for Black Wind compressors the maker states every 100 running hours if the machine stands in dust. A practical guide: if you saw wood, grind or sweep in the same room the compressor stands in, halve the interval.

How to tell it is time

The surest way is to look. A cartridge that has gone grey or brown right across is no longer working. The second sign is indirect: the machine takes longer to fill than it used to and runs hotter, because it cannot draw breath. And if the housing is cracked or does not seat, it is time whatever the cartridge looks like.

Blow it out, or replace it?

Blowing a cartridge out with compressed air looks as if it helped — but the fine dust is only driven deeper into the material and the flow does not come back. On a part this cheap that is not a trade worth making. Never blow from the dirty side outwards, and never put a damp cartridge back.

Unbranded compressor: choose by the thread

For older and unbranded machines there is no original filter to be had — and you do not need one. Universal metal filters are chosen purely by the male pipe thread on the inlet: we carry 3/8" and 1/2".

How to find the thread: unscrew the old filter and measure the outside diameter of the thread — 3/8" is roughly 17 mm, 1/2" roughly 21 mm. If you are not sure, photograph the inlet with the old filter on it and send it to us; we will recognise it from the picture.

What goes with it

The intake filter is one of the things a compressor needs regularly. Here is the rest.

• Compressor oils — changed at the same time as the filter
• Service kits — oil, filters and seals for one service, together
• Compressed air treatment — filtration and drying DOWNSTREAM of the compressor, not at the inlet
• Compressor noise — a clogged filter chokes the machine and raises the noise
• How to filter compressed air — which stage of filtration is enough for what

Ventilek says

A cartridge costing a few crowns decides whether your pump survives.

Friends, the intake filter is the cheapest part on the machine and the worst one to economise on. Dust that gets through behaves in the cylinder like emery — and a worn pump is not repaired, it is replaced. Change the cartridge faithfully with every oil change, and if you saw timber or grind right next to the compressor, sooner than that. One more thing: when you buy just the cartridge, check the housing. A cracked shell draws unfiltered air around the cartridge, and a new cartridge in it is money thrown away.

• Compressor oils
• Service kits for compressors

Frequent questions about intake filters

Should I buy the whole filter or just the cartridge?

When the housing is sound and seats properly, the cartridge is enough. You need the whole filter when the housing has cracked, the thread in it has broken off, or it does not seat — the machine then draws unfiltered air around the cartridge and a new cartridge would be wasted. In the table above each complete filter has its cartridge listed, and the other way round.

How often is the intake filter changed?

Normally once a year or together with the oil. In a dusty shop more often — for Black Wind compressors the maker states every 100 running hours if the machine stands in dust. Where sawing or grinding goes on next to the compressor, halve the interval.

Can a cartridge be blown out and reused?

We do not recommend it. Blowing it out looks effective, but the fine dust is only driven deeper into the material and the flow does not come back. At the price of a cartridge it is not worth it. Above all, do not blow from the dirty side and do not refit a damp cartridge.

My compressor has no brand on it — which filter do I take?

A universal metal one — chosen by the male pipe thread on the inlet. We carry 3/8" and 1/2". Measure the outside diameter of the old filter’s thread: 3/8" is roughly 17 mm, 1/2" roughly 21 mm. Or photograph the inlet and we will advise.

How do I tell which filter fits my ABAC?

By the pump designation, not by the type of compressor. You will find it on the plate of the compressor unit — the cast-iron part, not the receiver. In the table above the pumps are listed against each filter.

Does my compressor take one filter or two?

It depends on the machine — a pump with two inlets takes two filters. For Black Wind compressors this is stated on each filter’s own page, because it differs from model to model. If you are not sure, send us the model of the machine and we will check.

Fitment follows the data held against the products in our catalogue. The thread is given wherever the source states one; filters tied to a particular pump are not chosen by thread.