Quick Answer: Match the pump to the container first. For 5-gallon (35 lb) pails, use a manual bucket pump (3,500 PSI) or an electric bucket pump (6,000 PSI). For 120 lb drums, choose a 50:1–55:1 pneumatic grease drum pump such as the 9120 Air Drum Pump. For 400 lb / 55-gallon drums, specify a 50:1 or 60:1 air-operated pump with a drum-matched follower plate. In every case, the follower plate must match the drum’s inner diameter, and the air compressor must meet the pump’s CFM demand.
Related: complete guide to grease pumps · 5 gallon grease pump guide
What Is a Grease Drum Pump?
A grease drum pump — also called a grease barrel pump or grease dispenser pump — is a high-pressure transfer device that extracts grease directly from bulk containers (5-gallon pails, 120 lb kegs, or 55-gallon drums) and delivers it through a hose to a control gun or a centralized lubrication system. Pneumatic models use an air motor whose piston is larger than the grease piston; the area ratio between the two multiplies the air pressure into much higher grease pressure. A close-tolerance follower plate rides the grease surface down as the container empties, sealing against the drum wall so the pump keeps its prime and the grease stays clean.
ISOHITECH manufactures drum pumps, centralized lubrication systems, and dispensing accessories for fleet, mining, construction, and industrial maintenance. The selection logic below applies to any industrial grease drum pump; the specification examples come from ISOHITECH models.
Grease Pump Types by Container Size
5-Gallon (35 lb) Pails
Five-gallon pails are the standard container for small shops and mobile service. Two drive options cover this size. The manual 5 gallon grease pump fits 25–50 lb pails, develops up to 3,500 PSI, and delivers 1.2 oz per 28 strokes through a 6 ft high-pressure hose — no air or power required. Where outlets are available, the electric grease bucket pump (120V/230V AC) delivers up to 6,000 PSI at 100–200 ml/min with a 10 ft hose and included follower plate. It fits straight-wall pails of 290–330 mm diameter; tapered pails break the follower plate seal and starve the pump.
120 lb (16-Gallon) Drums
The 120 lb (54 kg) drum is the workhorse size for fleet bays and industrial maintenance. Pneumatic pumps dominate here. The ISOHITECH 9120 Air Drum Pump runs a 55:1 ratio on ordinary 40–140 PSI shop air, delivering 0.7 lb/min (317 g/min) while consuming about 5 cu.ft/min (150 L/min) of air. For higher line resistance, the 120 lb air-operated grease pump uses a 50:1 ratio to reach 7,500–10,000 PSI from a 30–150 PSI air inlet, with a dispense rate of 16–40 oz/min and NLGI 000–2 compatibility. Both mount through the drum bung with a cover, adapter, and follower plate.
400 lb / 50- to 55-Gallon (205 L) Drums
A pump for 50 gallon drum and 55-gallon (400–484 lb) containers serves high-volume users: mine sites, large fleet depots, and plants feeding centralized systems. The ISOHITECH grease drum pump family covers 30 L through 55-gallon drums at 50:1 or 60:1 ratios, output up to 8,700 PSI (600 bar), and flow of 1.5–4+ lbs/min. Because a full drum weighs 400 lb or more, pair the pump with a mobile base — the 200 L lubrication cart carries 250 kg on 260 mm wheels with a universal pump bracket, turning the drum into a movable lubrication station.
Setting Up a 120 lb (16-Gallon) Keg: Interfaces, Follower Plates & Adapters
The 120 lb (16-gallon, ~54 kg) keg is the most common bulk grease container in automotive, fleet, mining, and agricultural maintenance. Getting a keg station right depends on three mechanical interfaces: the drum cover, the follower plate, and the pump tube connection. The dimensions below come from the 120 lb grease drum specification guide — always measure the actual drum, because all values are nominal.
Keg Interface Dimensions
- Drum cover: approximately 15 in (381 mm) outer diameter.
- Pump tube opening (bung): 2-3/8 in (60.3 mm) — the industry-standard interface, accepting 50:1, 65:1, and 100:1 air-operated pump tubes as well as manual filler pump assemblies.
- Suction / pump tube length: 28–29 in (711–737 mm) to reach the full drum depth and achieve near-complete evacuation.
Follower Plate Sizing for 120 lb Kegs
A 120 lb keg requires a follower plate OD of 13.5–15 in (343–381 mm), matched to the measured drum inner diameter — a typical ~355 mm drum ID pairs with a 350 mm plate, as shown in the compatibility table above. The fit matters economically as well as mechanically: with a correctly sized plate, industrial testing shows recovery of up to 99.5% of the drum contents, while an undersized plate lets grease bypass the wiper and an oversized plate sticks and stalls. Replacement and retrofit plates are listed on the follower plate page.
Conversion and Adapter Options
Because the 2-3/8 in bung is a shared industry interface, a keg station can be re-equipped without replacing the drum. Swapping between a 50:1 tube and a 65:1 or 100:1 tube adds pressure margin for stiffer grease or longer hose runs, and a manual filler pump assembly can be fitted to refill smaller reservoirs from the same keg. When moving a pump between a keg and a 55-gallon drum, two changes are mandatory: swap the follower plate to the new drum diameter, and confirm the pump tube length — a keg-length tube will not reach the bottom of a full-height drum.
Hose layout deserves the same attention as the pump itself: every 50 ft of 3/8 in hose adds approximately 500 PSI of pressure drop at 1 lb/min flow. For runs beyond 100 ft, step up the hose diameter or the pump ratio. Pumps purpose-built for this container, such as the 120 lb air-operated grease pump, are supplied with the cover, adapter, and follower plate already matched to keg dimensions.
Manual vs Pneumatic vs Electric: Which Drive Type?
| Drive Type | Typical Pressure | Typical Flow | Power Needed | Best For |
|---|---|---|---|---|
| Manual lever | Up to 3,500 PSI | 1.2 oz per 28 strokes | None | Low-frequency service, field work, 5-gal pails |
| Electric (120/230V) | Up to 6,000 PSI | 100–200 ml/min | Standard wall outlet | Shops without compressed air; consistent duty |
| Pneumatic (50:1–60:1) | 5,000–8,700 PSI | 0.7–4+ lbs/min | Compressor, 3–22 CFM | Fleet bays, centralized systems, continuous use |
Pneumatic pumps are the default grease dispenser choice for high-volume work: the air motor stalls harmlessly when the gun closes, holding pressure without consuming air. Electric bucket pumps win where no compressor exists. Manual pumps remain the low-cost entry into bulk dispensing.
Electric Filler & Transfer Pumps: DJB and DCB Model Reference
Two electric pump families sit alongside the drum-mounted dispensing pumps above: DJB filler pumps, which refill centralized lubrication system reservoirs directly from 200 L drums, and DCB electromagnetic piston pumps, which meter oil in single-line resistance (SLR) systems.
| Model | Type | Max Pressure | Output | Link |
|---|---|---|---|---|
| DJB | Electric grease filler pump series | — | — | DJB filler pumps |
| DJB-F200 | Electric grease filler pump for 200 L drums | 1.0 MPa operating (relief valve at 1.2–1.5 MPa) | 200 mL/min constant; 1.1 kW motor | DJB-F200 pump |
| DCB | Electromagnetic piston pump series (SLR oil) | — | — | DCB pumps |
| DCB-2 | Electromagnetic piston pump for single-line resistance systems | 3.0 MPa (1.6 MPa on model 48228) | 0.24 mL per stroke; 1–4 L tank options | DCB-2 pump |
A filler pump is the practical companion to any centralized system fed from bulk drums: instead of pouring or scooping grease into the system reservoir, the DJB-F200 transfers it at 200 mL/min through a closed hose with a drum follower plate — no contamination, no air pockets. The DCB-2, by contrast, is a metering pump: each solenoid stroke delivers exactly 0.24 mL of oil into an SLR network of DPT resistance metering valves, with no rotating seals or shafts to wear.
What is a grease filler pump used for?
A grease filler pump transfers lubricant from a bulk container — typically a 200 L drum — into the reservoir of a centralized lubrication system. The DJB-F200 does this electrically at 200 mL/min within a 0.3–1.0 MPa working range, using a follower plate and closed hose so the grease never contacts shop air or debris. This keeps the main system reservoir clean and removes the mess and contamination risk of manual refilling.
Pressure Ratio Selection (Typically 30:1 to 75:1)
Industrial grease drum pumps typically range from 30:1 to 75:1 in pressure ratio. The ratio multiplies air pressure into grease pressure:
Grease outlet pressure (PSI) = Air supply pressure (PSI) × Pump ratio
On 100 PSI shop air, a 50:1 pump delivers up to 5,000 PSI at the outlet; a 55:1 pump delivers 5,500 PSI; a 60:1 pump delivers 6,000 PSI. The pump stalls automatically when system back-pressure is reached, so the real requirement is that stall pressure exceeds the total resistance of hose, fittings, and the lubrication point.
- Short hose runs, single gun, NLGI 0–1: lower ratios are sufficient.
- Standard workshop and fleet duty, NLGI 2: 50:1 is the industry default — it balances pressure, flow, and air consumption.
- Long hose runs, multi-point manifolds, centralized systems: 55:1–60:1 provides margin against line pressure drop.
- Cold environments or stiff grease: higher ratio compensates for viscosity rise; see the NLGI section below.
For reference, benchmarks such as the Macnaught P6-TR pair a 50:1 pump with a 10,000 PSI booster gun. ISOHITECH supplies aftermarket-compatible components. Brand names used for compatibility reference only. ISOHITECH is not an authorized OEM dealer.
Follower Plate & Drum Compatibility
The follower plate is the most common failure point in a drum pump installation. Its wiper seal must maintain contact with the drum’s inner wall across the full diameter. An undersized plate lets grease bypass the seal and pool above it; an oversized plate sticks and stalls. Match the plate to the drum — not the other way around.
| Drum Size | Drum Inner Diameter | Follower Plate OD |
|---|---|---|
| 30 L | ~270 mm | 265 mm |
| 60 L | ~318 mm | 313 mm |
| 120 lb (54 kg) | ~355 mm | 350 mm |
| 400–484 lb / 55 gal | ~571 mm | 566 mm |
Dimensions are nominal — always verify against the drum manufacturer’s specification. For replacement or retrofit plates, the ISOHITECH grease pump follower plate comes in 265, 285, 550, and 590 mm diameters with 30 or 40 mm center holes, zinc-plated steel construction, and a 6 mm NBR wiper edge rated for NLGI 0–3 greases.
Flow Rate & Cycle Time Estimation
Flow rate determines how fast technicians can work and how long a container lasts. Rated outputs from the ISOHITECH range:
- 9120 Air Drum Pump (55:1): 0.7 lb/min (317 g/min) — a 120 lb drum supports roughly 170 minutes of continuous dispensing.
- 120 lb 50:1 pump: 16–40 oz/min (0.47–1.18 L/min) depending on air supply and grease temperature.
- 50:1/60:1 drum pump family: 1.5–4+ lbs/min for high-volume transfer.
- Electric 5-gal bucket pump: 100–200 ml/min.
- Manual 5-gal pump: 1.2 oz per 28 strokes.
As a sizing rule, estimate daily grease consumption first. A few pounds per day suits a 5-gallon pail pump; a pail per week justifies a 120 lb drum; continuous multi-bay or centralized operation calls for the 55-gallon drum. These are approximations — actual flow varies with air supply, grease grade, and temperature.
Grease Drum Pump Selection Table
| Container | Recommended Pump | Type | Pressure Ratio / Max PSI | Flow Rate |
|---|---|---|---|---|
| 5 gal (25–50 lb pail) | Manual bucket pump | Lever | 3,500 PSI max | 1.2 oz / 28 strokes |
| 5 gal (35 lb pail) | Electric bucket pump | Electric 120/230V | 6,000 PSI max | 100–200 ml/min |
| 120 lb (16 gal) | 9120 Air Drum Pump | Pneumatic | 55:1 / 40–140 PSI air | 0.7 lb/min |
| 120 lb (16 gal) | 120 lb air-operated pump | Pneumatic | 50:1 / 7,500–10,000 PSI | 16–40 oz/min |
| 30 L – 55 gal (400 lb) | Grease drum pump family | Pneumatic | 50:1–60:1 / up to 8,700 PSI | 1.5–4+ lbs/min |
NLGI Grade & Temperature Considerations
Grease consistency drives three decisions: ratio, follower plate, and seal material.
- NLGI 000–0 (semi-fluid): flows readily; any pump type handles it, and light follower assistance is enough.
- NLGI 1–2 (standard industrial): the design center for most drum pumps. NLGI 2 requires a follower plate to feed reliably, especially in 120 lb and 55-gallon containers.
- NLGI 3 and stiffer: verify with the manufacturer before ordering — very stiff grease can exceed the pump’s self-priming capability and stall the follower plate’s descent.
Temperature acts through viscosity: a 120 lb pump rated for -20°C to +80°C moves far less grease per stroke at the cold end, so in winter budget extra pressure margin or warm the drum. For seals, standard NBR suits mineral-oil and lithium greases; synthetic, polyurea, or service above 60°C calls for PTFE or Viton seal kits.
Frequently Asked Questions
What is a grease drum pump and how does it work?
A grease drum pump is a high-pressure transfer pump that mounts on a bulk grease container — a 5-gallon pail, 120 lb keg, or 55-gallon drum — and dispenses grease through a hose to a control gun or lubrication system. Pneumatic models multiply shop air pressure by their ratio (for example 50:1) to generate grease outlet pressures of 5,000 PSI or more, while a follower plate seals the grease surface to maintain prime and prevent contamination.
How do I choose the best grease drum pump for a 5-gallon bucket vs a 55-gallon drum?
Start with daily consumption and available power. For a 5-gallon bucket, a manual pump (3,500 PSI, no utilities) or an electric bucket pump (6,000 PSI, wall outlet) is usually the best fit. For 55-gallon drums in high-volume shops, a 50:1 or 60:1 pneumatic pump with a drum-matched follower plate and a mobile cart handles continuous duty. Always confirm pail or drum diameter before ordering — 5-gallon pails need a straight-wall container of roughly 290–330 mm.
What pressure ratio do I need — 40:1, 50:1, or 60:1?
Multiply your available air pressure by the ratio to get grease outlet pressure. On 100 PSI shop air, 50:1 gives 5,000 PSI — enough for standard NLGI 2 workshop duty with moderate hose lengths. Choose 55:1–60:1 for long hose runs, centralized multi-point systems, cold conditions, or stiff grease. Higher ratios trade some flow and air efficiency for pressure margin.
What size air compressor do I need for a pneumatic grease drum pump?
Check the pump’s rated consumption, not just its pressure range. A 55:1 drum pump like the 9120 consumes about 5 CFM (150 L/min). For light intermittent use, 3–6 CFM at 90 PSI is sufficient; for continuous industrial duty, plan 15–22 CFM at 120–150 PSI and size the compressor about 20% above rated demand. Always install a filter-regulator-lubricator (FRL) upstream — dirty or dry air is the leading cause of premature air-motor wear.
Do I need a follower plate, and how do I match it to my drum?
Yes for NLGI 1–2 grease in any container larger than a cartridge. The follower plate prevents air ingestion, stops grease skinning, and enables near-complete drum evacuation. Match its outer diameter to the drum’s inner diameter — for example, 350 mm for a 120 lb drum or 566 mm for a 55-gallon drum — and confirm the center hole fits your pump tube (30 or 40 mm are common).
Can I move a 50:1 pump between a 120 lb keg and a 55-gallon drum?
Mechanically yes — both containers use the industry-standard 2-3/8 in pump tube opening — but two changes are required: swap the follower plate (approximately 343–381 mm for a 120 lb keg versus about 566 mm for a 55-gallon drum) and confirm the pump tube length matches the drum depth (typically 28–29 in for a keg; longer for a 55-gallon drum). A keg-length tube in a full-height drum leaves a large volume unreachable.
How much grease is left in a 120 lb keg after pumping?
With a correctly sized follower plate, industrial testing shows recovery of up to 99.5% of the drum contents. Without a follower plate — or with an undersized one — grease clings to the walls, the pump ingests air well before the keg is empty, and systems waste an average of about 15% more grease.
Shop ISOHITECH Grease Drum Pumps
Browse the full grease drum pump category for pneumatic, electric, and manual models from 5-gallon pails to 55-gallon drums, or visit the Grease Pump hub for type comparisons, selection guides, and troubleshooting resources.
Need Help Sizing a Pump for Your Drums?
Send us your container size, grease grade, and air supply — our engineers will match the pump ratio, follower plate, and hose kit to your application. Request a quote.
