There is a limit to how much pressure a single impeller can sensibly produce. Push for more and you end up with a large, fast-spinning impeller that is noisy, inefficient and hard on its bearings. Multistage pumps take a smarter route: stack several smaller impellers in series on one shaft, and let each one add a share of the pressure. The flow stays the same through all of them, but the head builds stage by stage, so a compact pump can reach pressures a single-stage design never could.
We supply multistage pumps from Calpeda, Ebara and Lowara in horizontal, vertical and inline forms, and can source other makes for a specific duty. Whether you write it as one word or two, multi stage pumps are about the same thing: pressure built across several impellers in series. The ranges are below, or call +44 1332 913500 for help choosing.
A multistage pump is a centrifugal pump with two or more impellers on the same shaft, all turning together off one motor. Liquid enters the first stage, gains pressure, moves into the second where more is added, and so on through the stack. The impeller design fixes the flow; the number of stages fixes the total head.
This is far more efficient than chasing the same pressure from one big impeller. Several smaller impellers keep the pump compact, ease the loads on shaft and bearings, and give better efficiency across the range. A multistage impeller pump will commonly reach heads from 50 m to over 300 m depending on stage count and impeller diameter.
Each stage is an impeller paired with a diffuser. The impeller flings the liquid outward and gives it speed; the diffuser turns that speed into pressure and feeds the flow into the eye of the next impeller. Stacked in series, the pressure climbs step by step. Because the liquid passes through one stage at a time, the pump reaches high pressure without needing a large impeller or high running speed, which is why multistage pumps run quieter and more efficiently than single-stage pumps at the same high-head duty.
Horizontal multistage pumps are the common form, stages laid out horizontally in a segmental casing with connections at each end. They cover water supply, boosting, irrigation, boiler feed and process duty, and are easy to get at for service.
Vertical multistage pumps stack the stages vertically for a small footprint, ideal where floor space is tight, in plant rooms, risers and packaged booster sets. Inline versions put suction and discharge on one centreline to simplify pipework.
Submersible multistage pumps are essentially borehole pumps, the stages stacked vertically in a slim casing to fit down a bore. Our borehole pumps page covers these in full.
Self-priming multistage pumps add a priming chamber to clear air from the suction line, letting the pump sit above the liquid without manual priming, for irrigation, rainwater harvesting and surface water supply.
Multistage pumps are built for long life with fairly simple upkeep. The multistage pump parts that wear over time are the impellers, the diffuser wear rings, the shaft seal and the bearings. Calpeda, Ebara and Lowara all keep good spares availability, and the modular build means individual stages, seals and bearings can be changed without pulling the whole pump from the system. Routine work usually means checking and replacing the mechanical seal, which is the most frequent wear item, inspecting impellers and wear rings for erosion, and checking the bearings. On clean water and good maintenance, expect five to ten years between major overhauls.
Selection means matching the pump curve to your duty point. You need the flow in m³/hr or l/s, the total head (static lift plus friction losses plus residual pressure), and the liquid. The number of stages is then chosen to hit the head at that flow: more stages for more head, larger impeller diameter for more flow. We supply Calpeda, Ebara and Lowara and source other makes where a job calls for it. Send the duty to +44 1332 913500 and we will specify the right pump.
If your questions have not been answered here, get in touch with our team for more information.
A multistage pump is a centrifugal pump with two or more impellers arranged in series on a single shaft. Each impeller adds pressure to the liquid, so the more stages, the higher the discharge pressure. The flow rate stays constant regardless of the number of stages. Multistage pumps are used wherever high pressure is needed from a compact, efficient package.
A single stage pump has one impeller and generates all its pressure in a single step. A multistage pump has multiple impellers in series, building pressure incrementally through each stage. For the same total head, a multistage pump is more compact, more efficient and runs more quietly than a single stage pump with a larger impeller.
A multistage impeller pump is simply another name for a multistage pump. It refers to the fact that the pump uses multiple impellers (stages) stacked in series to build pressure. Each impeller adds head to the liquid before passing it to the next stage.
The key components are the impellers (one per stage), diffusers or volute casings, the shaft, mechanical seal, bearings, suction and discharge casings, and wear rings. The mechanical seal and wear rings are the primary service items. Replacement parts are readily available for the Calpeda and Lowara ranges we supply.
Use a multistage pump when your system requires high head (typically above 40-50 metres) at moderate flow rates. A standard single stage centrifugal pump is more cost-effective at lower heads. If your duty requires high pressure for boosting, boiler feed, RO systems or high-rise water supply, a multistage pump is almost certainly the right choice.
A well-specified multistage pump running on clean water with routine maintenance typically lasts 10 to 20 years. The mechanical seal is the most frequent replacement item (every 3 to 5 years depending on duty), with impellers and wear rings replaced less frequently as they erode over time.
