Rotary Lobe Pump > SXApplication

The SX range of rotary lobe pumps has been designed for use on wide ranging applications within the Pharmaceutical, Biotechnology, Fine Chemical and Speciality Food industries. Being certified by EHEDG (European Hygienic Equipment Design Group) as fully CIP cleanable to their protocol, the SX range is ideally suited to applications where cleanability and corrosion resistance is paramount.

In addition the SX pump range also conforms to USA 3-A Sanitary Standard and all media contacting components are FDA compliant. The SX pump operates with a high efficiency, low shear pumping action for assured gentle handling of delicate and sensitive media. The SX pump range is also classified for use in potentially explosive atmospheres under the ATEX Directive 94/9/EC Group II, Categories 2 & 3, with temperature classification T1 to T4. The SX range is compact in size, capable of flow rates up to 115 m³/h and pressures up to 15 bar.

Standard Design Pump Gearbox

The SX pump with its conventional lobe pump design concept has a robust cast iron gearbox, which provides maximum shaft rigidity and easy oil seal replacement. The SX range in series 1 – 4 has a universal gearbox design. This gives the flexibility of mounting pumps with the inlet and outlet ports in either a vertical or horizontal plane, by changing the foot and its position.

The SX range in series 5 & 6 has dedicated gearbox castings, which also allows the inlet and outlet ports to be in either the vertical or horizontal plane. The SX series 7 has a dedicated gearbox casting allowing inlet and outlet ports in a vertical plane only.

Pump head Construction

The SX pump has sanitary design full bore inlet and outlet ports to International Standards, maximising inlet and outlet port efficiency and NPSH characteristics. Vertical porting and unique rotorcase internal profile enhances self-draining and self venting while maintaining optimum volumetric efficiency.

The SX pump has four lobe rotors, designed using CFD (Computational Fluid Dynamics) to develop the optimum rotor geometry – possibly the first rotary lobe pump to be developed using this technology. All rotors are rated to 150°C facilitating use with CIP/SIP processes.


How It Works



Alfa Laval rotary lobe pumps are conventional positive displacement pumps with rotor case, rotor case cover, rotors, rotor nuts, shafts, gearbox, shaft seals and elastomers. The pumps operate with no internal contacting parts in the pump head.

The SX can be supplied either as a bare shaft pump or mounted on a base plate complete with coupling, guard, gear motor and shroud for easy plug-and-play installation.

The standard materials of construction are 316L stainless steel for all wetted parts and painted cast iron for the gearbox. Other materials are available on request.

In addition, Alfa Laval manufactures all pump parts, including the rotor case and high-precision rotors. This facilitates maintenance and guarantees full interchangeability of spare rotor parts.

Operating principle

A gear train in the pump gearbox drives the rotors and provides accurate synchronization, or timing, of the rotors. The contra-rotating propulsion system has two rotors spinning in opposite directions within the pump head. Fluid is carried through the pump in the cavities formed between the dwell of the rotor and the interior of the rotor case.

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