Air Line Lubricators
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ARO-Flo Air Line Lubricators: Oil Mist for Pneumatic Equipment
Air tools, air motors, cylinders and valves with moving seals often need a small, steady supply of oil to run smoothly and last. An air line lubricator meters that oil into the air stream as a fine mist, at a constant ratio to the air flowing through it. This page carries 19 ARO-Flo mist lubricators across four series, from 1/8" to 1" NPT, with polycarbonate or metal bowls and rated flows up to 330 SCFM.
Does Your Air Line Need a Lubricator?
Lubricate only what needs it. The equipment's own manual is the deciding document.
- Air tools and air motors whose manuals call for lubricated air
- Cylinders and valves specified for lubricated service
- Not needed for equipment lubricated for life or specified for dry air, such as ARO 1/2" diaphragm pumps
- Keep blow-off and drying air unlubricated, on a separate branch
Flow and Bowl Capacity by Series
Choose the lubricator by the air flow it has to serve. Bowl capacity sets how often it needs refilling. Flow ratings are at 90 psi inlet pressure with a 7 psi pressure drop.
| Series | Ports and rated flow | Bowl capacity | Bowls on this page |
|---|---|---|---|
ARO-Flo 1000 |
1/8" 32 SCFM, 1/4" 51 SCFM |
0.6 oz polycarbonate, 0.7 oz metal |
Polycarbonate, metal |
ARO-Flo 1500 |
1/4" 51 SCFM, 3/8" 105 SCFM |
1.9 oz polycarbonate, 1.5 oz metal |
Polycarbonate, metal with sight glass |
ARO-Flo 2000 |
3/8" 85 SCFM, 1/2" 156 SCFM, 3/4" 222 SCFM |
4.3 oz polycarbonate, 3.7 oz metal |
Polycarbonate, metal with sight glass, metal |
ARO-Flo 3000 |
3/4" and 1" 330 SCFM |
3.7 oz metal |
Metal with sight glass, metal |
Reading an ARO-Flo lubricator part number
In L36341-110, the fourth digit is the series (1 = 1000 up to 4 = 3000) and the fifth is the port size (1 = 1/8" up to 6 = 1"). After the dash, the middle digit is the bowl: 0 = polycarbonate with guard, 1 = metal with sight glass, 2 = metal. So L36341-110 is a 2000 Series 1/2" lubricator with a sight glass metal bowl.
Setting the Drip Rate
ARO-Flo lubricators are siphon-type: the air flowing through draws oil up and through the sight dome, where you can count the drops. The adjustment screw in the sight dome sets the rate. Turn it counterclockwise for more oil and clockwise for less, following the + and - markings on the body. Because the drip rate follows the air flow, set it with air flowing through the lubricator at a steady, typical rate.
ARO's rule of thumb
Start at one drop per minute for each 10 SCFM of average flow. A branch averaging 20 SCFM gets 2 drops per minute, one averaging 50 SCFM gets 5. Then adjust to what the equipment manufacturer recommends.
Bowls, Filling and Oil
- Polycarbonate bowl Transparent, with a guard, so the oil level is always visible. Rated to 150 psi and 23°F to 125°F. Not for synthetic oils or oils with ester-based additives.
- Metal bowl Rated to 250 psi and 23°F to 175°F, and compatible with oils that polycarbonate cannot take. The sight glass version shows the level through a window.
- Filling under pressure A ball check valve in the body isolates the bowl, so the fill plug can be removed and oil added while the line stays in operation. Fill to the top of the bowl.
- Oil A good grade of non-detergent oil, such as ARO 29665, unless the equipment manual specifies otherwise.
Installing a Lubricator
- Install downstream of the filter and regulator, never ahead of them
- Place it as close as possible to the equipment, so the oil mist reaches it
- Mount with the bowl pointing down and air flowing in the direction of the arrow
- Match the piping to the lubricator's port size
- Turn the bowl so the sight glass faces the operator
- Depressurize before removing the bowl for service
Frequently Asked Questions
How many drops per minute should an air line lubricator deliver?
ARO's starting point is one drop per minute for every 10 SCFM of average air flow through the lubricator, so a line averaging 20 SCFM gets 2 drops per minute. ARO-Flo lubricators are siphon-type, so set the drip rate while air is flowing steadily, using the adjustment screw in the sight dome. Then check the equipment manual and fine-tune from there.
What oil should I use in an ARO-Flo lubricator?
A good grade of non-detergent oil, such as ARO lubricating oil part number 29665, unless the manual for the air-operated equipment specifies something else. If you use synthetic oil, or oil with ester-based additives, choose a lubricator with a metal bowl, because these substances are not compatible with polycarbonate.
Can I refill the lubricator without shutting off the air?
Yes. A ball check valve in the lubricator body restricts operating pressure to the bowl, so the fill plug can be removed and the bowl filled while the air line stays in normal operation. Remove the fill plug carefully and fill to the top of the bowl.
Where should the lubricator be installed?
Downstream of the filter and regulator, and as close as possible to the equipment it serves, so the oil mist reaches it before it settles out in the piping. Mount it with the bowl pointing down and the air flowing in the direction of the arrow, and match the piping to the lubricator's port size.
Which air-operated equipment should not get lubricated air?
Only lubricate equipment whose manual calls for it. ARO's 1/2" diaphragm pumps, for example, need no air line lubrication beyond the O-ring lubricant applied during assembly. Keep blow-off and drying air unlubricated as well, and use a separate, lubricated branch for the tools, cylinders and valves that need oil.
The Right Oil, in the Right Amount
Too little oil and seals and vanes wear early. Too much and oil ends up in exhaust air, on products and on the floor. A correctly sized lubricator with a properly set drip rate delivers just what the equipment needs, close to where it needs it.
Order the lubricators above, with a compressed air filter and air pressure regulator upstream. To combine all three, choose a pre-assembled FRL combination unit, or pair a lubricator with a piggyback filter regulator. Application selections are on the industry pages for car wash, packaging and general manufacturing.
Need help setting up lubrication?
Talk to ARO about lubricator sizing, drip rates or oil selection. Monday to Friday, 08:00 am to 5:00 pm CST.