Milk pumps are widely used in industrial applications. Cheese production is just one example for where companies have to rely on gentle conveying for their products so that the consistency is maintained. Dairies utilise milk pumps for the transport of milk or cream. Also in the production of yoghurt or ice cream, milk pumps are integrated into the production process.
Pumps are utilised as stationary or even also as mobile on tankers. Due to the product characteristics, special hygienic demands are placed on milk pumps. The product is highly perishable and must be protected from germs. Generally stainless steel of 1.4404 is utilised as the preferred material. The pumps should be self-draining and cavity-free so that cleaning in the plant (CIP) is possible without dismantling. It is also advantageous when a low surface roughness is ensured. Typical values are less than 0.8 µm. A formation of germ deposits is therefore hampered.
EHEDG or also 3A Certificates can be utilised as an indication for suitable materials for milk pumps. In the European Union, a manufacturer's certificate in accordance with the EU Directive 1935/2014 is required for milk pumps.
Due to the low viscosity, centrifugal pumps are widely used but also displacement pumps such as the HYGHSPIN twin screw pump are also utilised for milk pump applications.
Twin screw pumps impress in this field with their flexibility compared to centrifugal pumps. This is particularly of advantage when the unit is not only utilised as a milk pump but also for other media. The wide rpm range creates many possibilities. This means that other highly viscous media can also be conveyed. Very frequently encountered is the "dual use", the utilisation of the HYGHSPIN twin screw pump for the process and for the conveyance of cleaning liquids in the CIP mode. The volume flows for process and cleaning can therefore vary widely, without this presenting problems for the HYGHSPIN pump.
Furthermore, a HYGHSPIN twin screw pump can easily deal with greatly differing system characteristics. Centrifugal pumps are often limited in their regulating capabilities for such cases. HYGHSPIN twin screw pumps are also utilised for conveying larger volumes. If the HYGHSPIN twin screw pumps are utilised as milk pumps, then there is an advantage when conveying vat-stored milk, which contains relatively high-viscosity residues which can result in deposits, can be safely conveyed. Centrifugal pumps hereby come up against their design limitations.
Twin screw pumps indicate low NPSH values and therefore have a high pumping speed. As long as they are partially filled with products and the system is designed accordingly, then the twin screw pumps are self-priming. This is advantageous if the milk pump suction pipework must be evacuated. With a doubled rinsing mechanical seal, the HYGHSPIN twin screw pumps can run-safe in a dry condition so that there is no risk in this regard with evacuations.