Peristaltic pump
A peristaltic pump moves medium by squeezing a flexible hose or tube against a curved track with rollers or shoes. The medium touches nothing but the bore of the hose, so the pump has no seals, valves or moving parts in the wetted path.
In more detail
It is a positive displacement pump, so it sweeps a fixed volume per revolution and its flow follows shaft speed rather than discharge pressure. That makes it self-priming and repeatable enough to meter with, and it runs dry without losing a mechanical seal, because it has no mechanical seal to lose. The hose is the wear part, and changing it is most of what the wet end ever asks of you.
The hose is the pump
A rotor carries rollers or shoes around a curved track, and each one pinches the hose shut against it. The roller carries the medium trapped ahead of it towards the discharge. Behind the roller the hose springs back to its round bore, and the vacuum that creates draws the next slug of medium in from the suction line.
Nothing else touches what you are pumping. No impeller, no valves, no shaft seal, no gland. One component sits in the wetted path and it is a length of rubber, which is why the type turns up on duties that destroy the wet end of other pumps.
Flow follows the shaft, not the pressure
Each pass of a roller displaces the volume held in one occluded length of hose, so the flow is set by the bore and the shaft speed. Halve the speed and you halve the flow. Raise the discharge pressure and the flow barely moves, the way it behaves on any positive displacement pump. That repeatability is why the type gets used for metering and dosing, where the duty is a rate rather than a head.
A liability comes with that, and it is the one that catches people out. A positive displacement pump has no natural pressure ceiling, so a closed discharge valve means the pump keeps trying until something gives. A relief path is part of the installation, not an optional extra.
The duties it suits
Abrasive media point towards a peristaltic, because the slurry only ever runs through a rubber bore and there are no close clearances for grit to wear open. So do shear-sensitive media, because the medium is carried rather than accelerated. So does anything that would attack a mechanical seal, or that must not pick up anything from the pump, since there is no seal and no metal in the wetted path to give it anything.
Abrasive and shear-sensitive media both want pumping slowly, and that constraint appears nowhere on a performance curve. It is a selection decision taken before anyone reads a duty point off a chart, and it is the reason a peristaltic sized on flow alone can still be the wrong machine.
What it costs you
The hose is a consumable. It flexes under every revolution and it will eventually fail, so hose replacement is a planned running cost rather than a fault, and the pump has to be sited where you can actually get at it to do the job.
Discrete rollers also give you a pulsed flow rather than a smooth one, which usually wants a damper on the discharge where the downstream process or the instrumentation is sensitive to it. And the hose sets the pump's pressure ceiling, so a duty a rotary lobe or a progressive cavity pump takes comfortably can sit outside the range of a peristaltic passing the same flow. Take the pressure rating from the manufacturer for the specific pump and hose, not from the type.
Where a peristaltic sits against the pumps we carry
Peristaltic pumps are not part of our range. On the positive displacement side we supply rotary lobe and progressive cavity pumps, and all three types overlap on abrasive, viscous and shear-sensitive work. A progressive cavity pump moves thick or shear-sensitive product at a steady rate and tolerates solids. A rotary lobe pump strips down quickly and cleans in place, which is usually what decides it on hygienic duties.
Where a peristaltic is the right answer for your duty, we will tell you so rather than sell you round it. Send us the flow, head and medium and you will get that answer either way.
Frequently asked
How does a peristaltic pump work?
A rotor turns rollers or shoes around a curved track, pinching a flexible hose shut against it. Each roller carries the medium trapped ahead of it towards the discharge. Behind the roller the hose springs back to its bore, and the vacuum that creates draws the next slug in from the suction line.
What is a peristaltic pump used for?
Peristaltic pumps handle abrasive slurries, shear-sensitive product, and metering and dosing duties where the flow has to be repeatable. They also suit a medium that would attack a mechanical seal, because the medium touches only the bore of the hose and there is no seal in the wetted path.
What is the difference between a hose pump and a tube pump?
Both are peristaltic. A hose pump squeezes a thick reinforced hose with shoes or rollers and covers industrial flows and pressures. A tube pump squeezes thinner, more flexible tubing with rollers and suits low-flow dosing and laboratory work. Manufacturers use the two names for the two ends of the same principle.
Can a peristaltic pump run dry?
Yes, for far longer than a pump that relies on a mechanical seal, because a peristaltic has no seal in the wetted path to lose. A mechanical seal needs liquid to lubricate it, so on a conventional pump you take the liquid away and the seal goes. Check the manufacturer's dry running limit for the hose before you build a duty around it.
Is a peristaltic pump self-priming?
Yes. The hose recovering its shape behind each roller is what creates the suction, so the pump pulls air out of the suction line and primes itself. It also runs in reverse if you reverse the drive, which helps with clearing a line or emptying back to a tank.
Should you use a peristaltic or an air-operated diaphragm pump?
Air-operated diaphragm pumps earn their place in a narrower set of cases than their popularity suggests, mainly where there is compressed air on site and no electricity. Compressed air is expensive to produce, so the running cost is far higher than an electric drive, and the air supply's reliability and cleanliness become part of your pump. Where electricity is available, we would go electric.
Does Channel Pumps supply peristaltic pumps?
No. Our positive displacement range is rotary lobe and progressive cavity, which cover much of the same ground on abrasive, viscous and shear-sensitive duties. If a peristaltic is the right pump for your duty, we will say so rather than sell you round it.