Milk pumps

Milk pumps are widely used in industrial applications. In the production of cheese, for example, companies depend on gentle conveying of their products to ensure that consistency is maintained.  Dairies use milk pumps to convey milk or cream. Milk pumps are also integrated into the production processes for yoghurt or ice cream.

Pumps are used either in a fixed position or as mobile pumps on tankers. Because of the properties of the products, there are special hygienic requirements in place for milk pumps. The product is perishable and must be protected against germs. As a rule, the material used is stainless steel 1.4404. The pumps should be self-emptying and free of dead spaces so that cleaning in place (CIP) is possible without disassembly. Ensuring a low surface roughness is also an advantage. Values of less than 0.8 µm are typical. This makes it more difficult for germ deposits to form.

For milk pumps, EHEDG or 3A certification can be used as an indication of suitable design. In the European Union, a manufacturer’s certificate in accordance with EU Regulation 1935/2014 is required for breast pumps.

Because of their low viscosity, centrifugal pumps are often used as milk pumps, but positive displacement pumps such as HYGHSPIN screw pumps are also used.

Compared to centrifugal pumps, the flexibility of twin-screw pumps is impressive. This is of particular benefit if the unit is used not only as a milk pump, but also for other media. A wide speed range opens up many possibilities, also allowing other highly viscous media to be pumped. “Dual use” applications are very common, with a HYGHSPIN twin-screw pump used for both the process and for pumping cleaning liquids in CIP mode. The volume flows for process and cleaning can be very different here, without causing problems for the HYGHSPIN pump.

HYGHSPIN twin-screw pumps can also be used to cover a wide range of system characteristics. In such cases, centrifugal pumps are often limited in terms of control. HYGHSPIN twin-screw pumps are also used to pump large volumes. Where HYGHSPIN twin-screw pumps are used as milk pumps, they have the advantage when pumping milk for making cheese that residual quantities with higher viscosities resulting from settling can also be safely pumped. Here, centrifugal pumps are stretched to their design limits.

Twin-screw pumps have low NPSH values, giving them a high pumping speed. At least when partially filled with product and the system is designed accordingly, twin-screw pumps are self-priming. This is an advantage if milk pumps need to evacuate suction lines. With a double flushed mechanical seal, HYGHSPIN twin-screw pumps are safe to run dry, so there is no risk in this respect during evacuations.