Twin screw pumps
For hygienic applications, twin-screw pumps have been playing a greater role within the group of positive displacement pumps for several years now. Originally, these pumps were primarily used to convey oil products. It is only in recent years that the principle behind these pumps has become firmly established in food and beverage production and in the pharmaceutical, cosmetics and fine chemicals sectors.
These are innovative pumps that meet very high quality standards. They are made entirely of stainless steel. In the standard version, the twin-screw pumps have two spindles. A left-hand and a right-hand feed screw displace the product in the axial direction. Unlike PC pumps, which have a similar principle of operation and where the rotor or stator sometimes have to be replaced after a short time, twin-screw pumps operate with very little wear. The running screws do not come into contact and are designed to be wear-resistant, so that abrasion in the pumped medium is completely avoided.
Because the product is not centrifuged in the direction of rotation and then deflected, as is the case with centrifugal and rotary lobe pumps, conveying of the product is particularly gentle. The pumps also operate with extremely low pulsation, ensuring that they go easy on both the material being conveyed and the production line.
Other features of our twin-screw pumps include their high suction capacity, which is characterised by low NPSH values and works to counteract cavitation. Not only is it possible to convey low and high viscosity products – including with low gas content – with one and the same pump, it can also be used to carry out CIP cleaning. This saves space and money, because there is no need to install a second pump for CIP, reducing expenditures on measuring, control, piping and valve systems, and on cabling.
As a rule, hygienic twin-screw pumps come with EHEDG hygiene certification. They are easy to disassemble and conveying lumpy products up to 45 mm in diameter is no problem. Double-flow high-pressure twin-screw pumps are available for pressure differences of up to 50 bar.
Both the pump outlet and the two pump inlets are offered in different nominal diameters to cover a performance range of up to 50 bar. This is particularly important when pumps and heat exchangers or filtration systems are operating together.
In all pump designs, the position of the mechanical seals is in line with the best available technology in pump design. They are fully within the area of flow and feature excellent flushing, cooling and cleaning. The mechanical seals are sturdy and wear-resistant and are single or double-acting depending on the application. All elastomers that come into contact with the product are designed as FDA-compliant moulded rings, making cleaning extremely easy.
Hygienic twin-screw pumps are the natural choice for demanding pumping jobs. They are used for example to convey processed cheese, fondant mass, viscous dough, sausage meat, whole egg, frozen orange juice concentrate or yeast cultures. In the personal care and pharmaceutical products sector, twin-screw pumps ensure excellent quality in creams, toothpastes, body lotions and medicines sold to customers.