How centralised lubrication works
Every system on this site is built from the same four parts, arranged differently for the job. Here's what each part does, how the three metering architectures actually dose a point, and why a point at the far end of a long pipe run doesn't get less lubricant than one right next to the pump.
The building blocks
Pump, distributor, pipe assembly, control system
However a system is configured, it breaks down into the same four parts. The diagram shows how they connect; the cards below describe what each one actually does.
Pump
Provides the lubricant and the pressure to move it. Motor-driven pumps run continuously or on a timed cycle; manual pumps are worked by hand on smaller systems. See our lubrication pumps.
Distributor
Splits the flow from the pump into a metered dose for each lubrication point. How it does that — by flow resistance, by piston displacement, or in strict sequence — is what separates the three architectures below. See our distributors.
Pipe assembly
Carries lubricant from the pump to the distributor, and from the distributor out to each point — pipe joints, fittings, and flexible or rigid tubing. It's plumbing, not metering: on a volumetric system, the dose at a point doesn't depend on how long its pipe run is.
Control system
The pump's own timer, or the host machine's PLC, decides when a cycle runs. A pressure switch and a level switch close the loop, so a blocked line or a low reservoir raises a fault instead of a point quietly running dry.
The mechanism
Three ways to meter a dose
This is about how each architecture doses a point, not which one to choose for a given machine — for that, see the selection guide, which matches point count and working pressure to an architecture.
Resist type — metering by flow resistance
The simplest architecture. Lubricant is pushed through a fixed restriction — a small-diameter passage sized into the distributor — on its way to each point. Because the restriction is a fixed passage rather than a moving part, the dose split between points is only proportional, not individually guaranteed the way a piston-metered dose is. That's a fine trade for the light machinery it's suited to — printing, packaging, small tools — where point counts are low and the tolerance doesn't matter.
Volumetric — metering by piston stroke
A volumetric distributor doses by displacement, not by pressure. Each outlet has its own small piston, and one stroke of that piston discharges a fixed volume — set only by the piston's diameter and travel.
That's why the dose delivered to a point close to the pump and a point at the end of a long pipe run can be identical. The distance the lubricant travelled to get there doesn't enter into the metering at all — only the piston's own geometry does. It's the reason volumetric systems suit machine tools, textile machinery, plastics and elevators, where points are spread across the machine at very different distances from the pump.
Progressive — metering in strict sequence
A progressive distributor is built from a chain of small blocks, each feeding one outlet. They don't fire together: block one has to complete its stroke before block two can move, block two before block three, and so on round the chain — then it repeats.
That interlock is what makes a progressive system self-checking. Because the blocks are mechanically forced to take turns, a single blocked outlet stalls the whole chain and shows up immediately as a pressure rise at the pump, rather than silently starving just that one point. It's why progressive systems suit construction and engineering machinery and heavy-duty bearings, where a missed point is expensive and a stalled system needs to be obvious. See how a blockage is diagnosed in our troubleshooting guide.
Running it
What decides when a cycle runs
The fourth part from the diagram above, in more detail — two ways to start a cycle, and two ways to monitor one.
The pump's own timer
Simplest to set up: the pump has a built-in programmer that fires a cycle on a fixed schedule, independent of what the machine is doing. Straightforward where duty is steady.
The host machine's PLC
Wired into the machine's own controller, so lubrication cycles are tied to actual running time rather than the clock — a machine that's stopped doesn't keep burning through lubricant while it waits.
Pressure switch
Fitted to the delivery line, it signals when pressure has risen beyond the expected range — the tell for a blocked distributor outlet. See our accessories.
Level switch & indicator
Fitted to the reservoir, it signals before the pump runs dry, so a system due for a refill raises a fault instead of quietly starving every point downstream.
Need a hand specifying a system?
Tell us the machine, the lubricant and the number of lube points, and we'll come back with the right pump and distributor combination.