A 55-gallon drum grease pump bolts onto a standard 400 lb open-head drum and turns shop air into continuous high-pressure delivery through a 50:1 air-operated, double-acting reciprocating piston. For ratio selection and system design, see the 55 gallon drum grease pump system design guide.
Key Specifications
| Parameter | Standard 50:1 | Heavy-Duty 50:1 |
|---|---|---|
| Pump ratio | 50:1 | 50:1 |
| Max outlet pressure | 7,500 PSI (517 bar) | 8,700 PSI (600 bar) |
| Flow rate | 1.19 – 1.76 lb/min | up to 4.0 lb/min |
| Air inlet pressure | 70 – 150 PSI (4.8 – 10.3 bar) | 100 – 150 PSI (6.9 – 10.3 bar) |
| Air consumption | 3.6 CFM @ 150 PSI | 5.0+ CFM @ 150 PSI |
| Air inlet connection | 1/4″ NPT (F) | 1/4″ NPT (F) |
| Grease outlet connection | 1/2″ NPT (M) | 1/2″ NPT (M) |
| Compatible drum | 400 lb (55-gal) open-head | 400 lb (55-gal) open-head |
| Drum inner diameter | 572 – 590 mm (adjustable follower plate) | 572 – 590 mm (adjustable follower plate) |
| Follower plate seal | Polyurethane wiper lip | Reinforced PTFE composite |
| Stroke volume | ~4.5 cc/stroke | ~9.0 cc/stroke |
| Wetted materials | Carbon steel, stainless steel balls, Buna-N seals | Carbon steel, stainless steel balls, PTFE and UHMWPE seals |
| Operating temperature | -20°C to +60°C | -20°C to +80°C |
| Pump weight (pump only) | ~4.5 kg (9.9 lb) | ~6.2 kg (13.7 lb) |
How the 50:1 Ratio Works
Outlet pressure equals inlet air pressure x 50: 100 PSI x 50 = 5,000 PSI; 150 PSI x 50 = 7,500 PSI at maximum inlet. The double-acting motor pumps on both strokes for continuous delivery; at 60 cycles per minute the standard pump moves ~4.5 cc/stroke x 60 cycles/min = ~270 cc/min, and the heavy-duty version displaces ~9.0 cc per stroke.
Drum Fit and Follower Plate
The pump mounts through a steel cover on a 400 lb (55-gal) open-head drum. The adjustable follower plate covers drum inner diameters from 572 to 590 mm and rides the grease surface down to keep the inlet primed and air out. The standard plate uses a polyurethane wiper lip; the heavy-duty plate uses a reinforced PTFE composite. Sizing details are on the follower plate page.
Grease Compatibility
NLGI #000 through #2 pump with excellent flow on both versions. NLGI #3 is workable but needs more than 100 PSI inlet air and delivers slower, especially in the cold. NLGI #4 and stiffer grades are not recommended. When changing grease type, clean pump and lines first; incompatible thickeners can harden or separate inside the pump.
Limits to Check Before You Order
- Hose and fitting ratings. Every discharge component must be rated to the pump’s maximum outlet pressure; general hydraulic hose in the 3,000 to 5,000 PSI class is not sufficient.
- Stiff grease in the cold. NLGI #3 at low temperature needs higher inlet pressure and delivers slower output.
- Grease changes. Switching grease types requires cleaning the pump and hose, not just swapping drums.
- Non-standard drums. Drum inner diameters outside 572 – 590 mm need follower plate confirmation before ordering.
High-pressure grease can penetrate skin and cause serious injection injury; depressurize the line before servicing fittings.
Bulk Filling: Feeding Grease Guns from a 55-Gallon Drum
Fleet shops and busy maintenance departments buy grease by the 55-gallon drum because the unit price beats cartridges and pails decisively — but the drum is only a win if you can actually get the grease out and into guns without wasting half of it. Anyone who has scooped NLGI 2 grease from a drum with a spatula knows how slow and messy that route is. Three setups solve it properly:
- Drum-mounted air pump with a filler hose. The configuration on this page: mount the pump, drop in the follower plate, and pressurize the drum. Guns load through a filler coupler in seconds with no air pockets.
- Hard-plumbed bulk line to a wall reel or bench dispenser. Larger shops run the pump’s output through high-pressure hose to one or more dispensing points, so several techs can fill guns without walking to the drum.
- Drum-lid gun deck. An alternative where the lid itself carries the pump and a gun dock — the whole drum becomes the grease station. Alemite and Lincoln both build this class of equipment (verified in their bulk catalogs), alongside ISOHITECH equivalents.
For loading technique at the gun end — bleeding air, filling the barrel, avoiding the classic mess — see the manual grease gun guide, or how to load a grease gun from a bucket for pail-based setups. The full engineering side — pressure ratios, line sizing, NLGI grade effects — is covered in the companion 55-gallon drum air grease pump system design guide.
Moving and Mounting a Full Drum
A full 55-gallon drum of grease weighs several hundred pounds — plan the logistics before the truck arrives, not after:
- Use a drum truck or dolly. Rolling a full drum across the shop on a dedicated drum cart is routine; manhandling one is not. Position the drum at its final pumping spot before mounting the pump.
- Leave headroom for the pump and lid. The pump tube, lid assembly, and air line add height — a low shelf or mezzanine edge that fits a bare drum may not fit a rigged one.
- Keep the air supply reachable. These pumps run on shop air; siting the drum next to an air drop avoids running hoses across walkways.
- Chock or strap the drum. A tall, top-heavy drum on a smooth floor is a tipping hazard once the pump handle and hose are attached.
Typical Applications
- Fleet service bays and truck shops with daily greasing
- Agricultural equipment service in seasonal maintenance windows
- Construction and earthmoving equipment workshops
- Plant maintenance departments feeding centralized lubrication circuits
What Is Supplied
A standard assembly includes the pump unit, steel drum cover, adjustable follower plate, high-pressure discharge hose, swivel fitting, and grease control valve or dispensing gun. Confirm hose rating and thread standard at order.
Share your grease grade, drum supplier, and air pressure and we will confirm the configuration. Request a drum pump quote.
Frequently Asked Questions
When should I choose a 55-gallon drum pump instead of a keg pump or a manual gun?
Choose the drum pump when consumption is continuous: fleets, production lines, shops greasing many points daily. If use is intermittent or the pump must move, a grease keg pump for 120 lb containers fits better; a manual gun suits a few occasional points.
What outlet pressure does the 50:1 ratio produce?
Multiply inlet pressure by fifty: 100 PSI x 50 = 5,000 PSI; 150 PSI x 50 = 7,500 PSI. The heavy-duty version is declared to 8,700 PSI (600 bar).
How much compressed air does the pump need?
The standard pump consumes 3.6 CFM at 150 PSI across a 70 to 150 PSI inlet; the heavy-duty pump needs 5.0+ CFM and starts at 100 PSI. An undersized compressor shows up as slow cycling and falling output.
Can it handle NLGI #3 grease?
Yes, with limits. NLGI #3 needs more than 100 PSI inlet air and flows slower than #2, and cold weather strengthens both effects. NLGI #4 and stiffer grades are not recommended.
My drum inner diameter is outside 572 – 590 mm. Will it fit?
The adjustable plate covers 572 to 590 mm. Outside that range, measure the drum inner diameter and confirm sizing before ordering; a loose plate lets grease bypass the wiper and admits air.
What hose rating do I need?
Hose, swivel, and gun must all be rated to the maximum outlet pressure, not the inlet air pressure.
Can I switch grease types in the same pump?
Only after cleaning. Flush the pump and line before introducing a different thickener family, because some combinations harden or separate when mixed. Plan changeovers at drum swaps.
What differs between the standard and heavy-duty versions?
Both are 50:1 double-acting pumps for 400 lb drums. The heavy-duty version raises the declared maximum outlet to 8,700 PSI (600 bar), flows up to 4.0 lb/min, uses PTFE and UHMWPE seals, and extends the range to -20°C to +80°C.
What maintenance does the pump need?
Keep the air supply filtered and regulated, drain moisture regularly, and inspect the follower plate wiper and hose. A pump that cycles but delivers nothing usually needs the inlet check ball cleaned.
Who makes this pump and how do I order?
IsoHiTech Lubrication Systems supplies air-operated drum pumps, follower plates, hoses, and fittings, founded in 2023, engineering since 2006. Send your grease grade, drum dimensions, and air supply to inquiry@isohitech.com, or get a configuration check.
Can I fill grease guns directly from a 55-gallon drum?
Yes — that is the standard bulk setup. A drum-mounted air grease pump with a filler hose couples to the gun’s filler valve and loads it in seconds. Without a pump, filling from a drum means scooping grease by hand, which is slow, messy, and introduces contamination.
Do I need a follower plate with a drum grease pump?
On 55-gallon drums, yes. The follower plate rides down on the grease surface, wiping the drum wall and feeding grease to the pump inlet. Skipping it invites air pockets, loss of prime, and grease stranded on the drum walls that never reaches the pump.
