A flexible impeller pump sits in an unusual spot between pump families: it primes like a positive displacement pump but moves liquid as smoothly as a centrifugal one. A rubber or thermoplastic impeller with bendable vanes turns inside an offset housing, the vanes flexing as they pass a cam to open and close chambers that carry the liquid round to the outlet. The result is a gentle, low-pulsation flow that suits delicate and viscous products alike.
We supply flexible impeller pumps from Jabsco, the established name in this design, and can source other makes where a job calls for it. The Jabsco ranges are below, or call +44 1332 913500 for help choosing.
The pump body is a simple cylindrical housing with an inlet, an outlet and a raised cam on one inside wall. The flexible impeller, usually moulded rubber, sits on the drive shaft with its vanes pressed against the housing. As it turns, the vanes leaving the cam spring open and draw liquid in behind them; the vanes meeting the cam bend over and squeeze liquid out ahead. Because those vanes seal against the housing, the pump primes itself from dry and can run in either direction.
That combination, self-priming, gentle handling and bi-directional running, is what makes the design useful where a centrifugal pump would lose prime and a gear or piston pump would chew up the product. Rubber impeller pumps are a mainstay wherever liquids need moving without being beaten up on the way.
Their gentle handling and self-priming make flexible impeller pumps a fixture across several industries:
Hygienic and non-hygienic variants are both available, so the same basic pump covers sterile process duty and everyday transfer.
We stock the Jabsco flexible impeller range, which spans light-duty through to industrial and food-grade duties:
We also carry flexible impeller accessories, including replacement impellers, seals and service kits, so pumps are quick to maintain.
Choosing a flexible impeller pump comes down to the liquid (its viscosity, any soft solids, temperature and whether the duty is hygienic), the flow rate you need, the head, and how the pump will be driven. The impeller material and body material are then matched to the fluid. Because the impeller is a wear part, it is worth keeping a spare on hand for any pump in regular service. Tell us about your liquid and duty on +44 1332 913500 and we will point you to the right Jabsco model.
If your questions have not been answered here, get in touch with our team for more information.
A positive displacement pump that moves liquid with a flexible, usually rubber, impeller whose vanes bend as they pass a cam inside the housing. This creates chambers that open to draw liquid in and close to push it out, giving smooth, self-priming, low-shear flow.
Gentle transfer of liquids that must not be sheared or aerated, and self-priming transfer of viscous fluids and liquids with soft solids. Common in food and beverage, pharmaceutical, cosmetics, marine and farming, handling everything from beer and milk to delicate process fluids.
Yes. The impeller in this design is almost always moulded rubber, so rubber impeller pump is just another name for a flexible impeller pump. Some impellers use thermoplastic compounds for particular chemical or temperature needs, but the principle is identical.
Only very briefly. The impeller relies on the pumped liquid to lubricate and cool it against the housing, so running dry quickly wears or damages the vanes. Flexible impeller pumps prime well, but they should be primed and kept wet in normal running.
The impeller is the main wear part and its life depends on the liquid, the running hours and how often the pump sees dry running. On regular duty it is normal to replace it periodically as part of routine maintenance, which is why we keep flexible impeller accessories and service kits in stock.
