Barrel pumps

Barrel pumps draw grease straight from the container and replace decanting by hand. The pneumatic ones work on a ratio principle: a large-area air piston drives a small-area grease piston, and the area ratio multiplies the air pressure into grease pressure. That is why 4 to 8 bar of shop air can produce grease pressures in the hundreds.

Source: DropsA manufacturer data, retrieved 31 July 2026 – IPG · PPG · IPO · CannonPump · HPM · MGF · PPO. The figures in the respective datasheet are binding.

The PPO range is the oil transfer pump of the programme: 28 to 40 l/min at 8 bar line pressure, air inlet 1/4″ or 3/8″ BSP, oil outlet 1/2″ or 3/4″ BSP. The versions are matched to the drum — 50–60 l, 180–220 l or 750–1500 l — and the ratio follows from that: the larger the drum and the heavier the oil, the higher the chosen ratio.

The ratio is the number that decides

20:1 at 8 bar line pressure gives 160 bar, 75:1 gives 600 bar — exactly the maximum figures DropsA publishes for the IPO and IPG ranges.

From which follows the point maintenance keeps missing: if line pressure drops from 8 to 5 bar, available grease pressure falls in the same proportion. A barrel pump that works fine in the morning and fails on the late shift usually has a compressed-air problem, not a pump problem. The PPG range is explicitly rated for 2.5 to 8 bar.

Grease or oil — the ranges are not interchangeable

The split is unambiguous: IPG for grease, IPO for oil. The pressure shows it — 600 bar against 160 bar. Oil does not need that pressure because it has no yield point to overcome; grease does. The IPG is the only range rated to NLGI 3, the other grease pumps to NLGI 2. What the consistency classes mean is covered in our article on NLGI classes.

Manual or pneumatic

HPM and MGF work without compressed air, and the difference between them is pressure against volume. The HPM reaches 400 bar and delivers 40 to 60 grams per ten lever strokes — it is for greasing, where high pressure is needed. The MGF delivers 400 grams over the same ten strokes, roughly eight times as much, but without high pressure: it is a transfer pump for filling containers. The HPM covers 15, 16 and 18–30 kg containers, the MGF 18–30 kg and 50–60 kg. The CannonPump sits between them at 125 cm³/min, 250 bar and a 3/8″ BSP outlet.