What a 5:1 Air-Operated Oil Pump Is
A 5:1 air-operated double-acting oil pump moves oil from a closed drum to a dispensing point using shop air as the only power. The 5:1 ratio is a nominal multiplier, roughly 5 bar of oil pressure per 1 bar of air. Double-acting means oil moves on both strokes of the piston, so there is no dead return stroke. Within the oil pump family, air-operated designs fill the gap between manual and electric drive; our guide to the three basic types of oil pumps shows where they fit.
Performance and Connections
The core figures first, then the port details.
| Item | Figure |
|---|---|
| Pump ratio | 5:1, nominal |
| Flow | 12-38 L/min |
| Air supply | 5-8 bar (70-115 psi) |
| Outlet pressure | 40-51.7 bar (580-750 psi) |
| Drum range | 50-220 kg |
| Pump weight | 5-7.7 kg |
Air inlet is 1/4 inch with BSP or NPT thread; the oil outlet is 1/2 or 3/4 inch, again BSP or NPT. At mid-range settings the pump fills a 5 L measure in seconds, not minutes.
Oils It Moves
The pump handles engine oils from 0W-20 through 20W-50, synthetics, hydraulic oils, ATF, and differential oils. The viscosity ceiling is the SAE 240 gear-oil grade, about 1500 cSt, and thicker oil simply flows slower. Waste or used oil is a separate duty, since abrasives and fuel dilution wear a transfer pump faster; confirm that application before ordering. Where the job is bulk fluid transfer rather than drum dispensing, an electric bucket pump is the alternative tool, and our oil filtration guide covers the clean-oil side.
Air Supply Reality
Feed the pump 5-8 bar of clean, dry, regulated air through a regulator and water trap. At 8 bar inlet the outlet sits near 40 bar; the ratio stays nominal because the pump is flow-limited at the top of its range. When flow feels slow, check air volume and oil temperature before blaming the pump.
Mounting Choices
Drum mounting bolts the pump to the bung with a two-stage suction tube; tube lengths run 730-940 mm to follow drum depth across the 50-220 kg range. Wall mounting hangs the pump on a bracket with a short 175 mm tube for fixed fill points. A trolley suits shops that roll oil between bays. Fixed stations take drum mounts, tight floors take wall mounts, and moving oil takes the trolley.
Materials and Seals
Wetted bodies come in aluminum, carbon steel, or stainless steel to match the fluid and the site. Seals come in NBR, PU, or FKM; confirm fluid compatibility at ordering instead of assuming a default. Where a steady mechanical drive fits better than air, a trochoid pump is the alternative; ask our team for a quote to compare the two.
Frequently Asked Questions
What does the 5:1 ratio mean?
It is a nominal pressure multiplier: about 5 bar of oil per 1 bar of air. At 8 bar inlet the outlet sits near 40 bar.
What does double-acting mean?
Oil moves on both strokes of the piston, so flow never pauses for a return stroke. A single-acting design idles on every second stroke.
Which oils can it pump?
Engine oils from 0W-20 through 20W-50, synthetics, hydraulic oils, ATF, and differential oils. The ceiling is the SAE 240 grade, about 1500 cSt.
Which drums does it fit?
Closed drums from 50 to 220 kg. The suction tube follows drum depth, with 730-940 mm tubes for drum mounting.
What air supply do I need?
5-8 bar of clean, dry, regulated air. Fit a water trap and regulator ahead of the air inlet.
Why does flow slow down in winter?
Cold oil thickens and resists the piston. Warm the drum toward room temperature instead of raising air pressure at the pump.
Drum, wall, or trolley mounting?
Drum mounting suits fixed fill stations, and wall mounting saves floor space. A trolley suits oil that moves between bays.
Can it pump used oil?
Waste oil is a separate duty because abrasives and fuel dilution accelerate wear. Confirm the application before ordering.
What do I specify when ordering?
List drum size, mounting style, port threads, and seal material, then contact us for a quote to confirm the build. We reply with a matched build and tube length.
Who builds these air-operated oil pumps?
IsoHiTech Lubrication Systems, founded in 2023, engineering since 2006, builds and supports every unit. Email inquiry@isohitech.com for specifications and a quotation.
