How Circumferential Piston Pumps work
Circumferential piston pump is a type of positive displacement pump that operate using two interlocking rotors which draw fluid into the pump chamber and move it through the chamber using rotational mechanical force. The rotors do not touch each other or the pump housing directly, so the fluid is moved through the pump without any mechanical contact, resulting in gentle handling of the fluid and less damage or shear to it.
Circumferential piston pumps are capable of handle fluids of both low and high viscosity. For low viscosity fluids a circumferential piston pump with alloy rotors is best suited, these rotors can be run with very close clearance to the fluid head without the risk of galling or seizing in the event of inadvertent pressure surges causing contact. The combination of the rotor geometry and the tight tolerances results in low slip operation, with a long sealing path between the pump inlet and outlet. This results in high efficiency, excellent priming ability, precise metering capability, and superior flow control.
Furthermore, the large fluid cavities of the rotors and the generously sized anti-cavitation ports allow for efficient pumping of high viscosity fluids, slurries, and even liquids containing large chunks or particles.
Circumferential piston pumps can handle a wide range of fluids, including those with high viscosity, shear-sensitive or abrasive properties. They are also self-priming and can generate high pressures and flow rates.
Advantages of Circumferential Piston Pumps
The large fluid cavity allows circumferential piston pump to handle large sensitive solids, high viscosity media and abrasive liquids. The combination of these features means that circumferential piston pump offers a gentle pumping action with reduced risks of damaging sensitive liquids. The action of the interlocking rotors delivers a very gentle, pulse-free pumping action with the high suction capacity necessary for allowing thick mixes to be drawn into the pump without any separation of the ingredients. The reduced pressure and velocity between the outer edge of the rotor and the chamber wall also prolongs the life of the pump and minimizes heat within the pump head.
The pumps offer bi-directional flow, easy SIP and CIP cleaning for fast cleaning cycles and are simple to maintain. Rotors and seals can be inspected by simply removing the front cover, which gives ready access to the rotors and enable their removal for inspecting seals. Maximum service life can be achieved even under severe operating conditions where fluids are non-lubricating or abrasive. This capability is due to the absence of contact between the bearings and the pumped fluid, nor is there sliding or rolling contact and rotor-to-rotor contact. Where high viscosity fluids and solids are involved, the large fluid cavities of the rotors, together with the large easy-entry anti-cavitation ports enable efficient pumping.
The longer sealing path of the circumferential piston pump means that the rotor and body are more complex in their design. The advantages that flow from these improved characteristics make the effort and expense well worthwhile in the majority of applications where the consistent, higher pump performance and reduced product degradation is of concern to the pump user.
circumferential piston pump in AxFlow’s product portfolio all benefit from attention that has been given to extending pump life, delivering economic performance and return on investment. Models are available constructed from 316 stainless steel and non-galling alloy rotors. Although not common to all types, examples of developments include the positioning of static hubs in the cover, as opposed to the body, to improve flow and reduce ‘dead spots’; using greased lube bearings to provide positive lubrication to all bearings over the entire speed; the provision of shorter shafts to reduce overhung load and improve seal and bearing life; locating gaskets on the front cover to enable easier cleaning for products containing small particulates and increased commonalty of parts.
- High reliability.
- Easy maintenance.
- Small footprint area.
- Suitable for mobile skid mounting.
- No slippage on product over 200 cP.
- Extremely gentle and smooth pumping action.
- Wide operating temperature range (-50⁰C to +150⁰C).
- Viscosities up to 500.000cP
- No galling or seizing.
- An increased priming capability.
- Higher pressure capabilities.
- No product ingress between rotor face and rotor case.
Applications
Circumferential piston pumps are synonymous with sanitary and hygienic products processing. Typical applications include personal care products, excipients, medicines, dairy products, confectionery, cakes, biscuits and sauces. Although there is still no legal obligation on food manufacturers to use hygienically certified fluid handling equipment in Europe, the ever-increasing costs both financially and potential harm to a brand’s reputation resulting from hygienically defective products, has meant that never has there been so much pressure on manufacturers of foods and sanitary products to utilise the correct hygienic process equipment in the sight of the law. All circumferential piston pump available from AxFlow for such duties comply will all relevant international standards.
The roles for circumferential piston pumps in challenging industry sectors should not be overlooked. Their ability to pump slurries and pastes makes them perfectly suited to paper and pulp production, ceramics, coatings, plastics and chemicals.
Whilst for certain applications and duties there are areas where circumferential piston pumps could be employed, careful consideration must be given to the nature of the media being pumped and the expectations required of the pumps before a final decision should be made. For applications where product degradation, viscosity, abrasion, pressure and life-cycle costs are of higher concern, the circumferential piston pump should be employed.
Why buy circumferential piston pumps from AxFlow?
AxFlow provides circumferential piston pumps that cater to an extensive variety of industries and applications. Exclusive to AxFlow, you will be provided with personalized recommendations from highly experienced process engineers, and access to the most prominent process technology manufacturers that are independent of the manufacturer. If you require assistance in selecting the appropriate pumps that satisfy your requirements, feel free to contact AxFlow without any delay. AxFlows engineers and specialists can help with the selection process, specifications, installation, and maintenance of your fluid handling equipment.
