Twin screw pumps
Twin screw pumps have played a major role for many years within the group of displacement pumps for hygienic applications. Originally, these pumps were used primarily for the transportation of oil products. Only in the past few years has this pumping principle firmly established itself in the food and beverage industries as well as pharmaceuticals, cosmetics and fine chemicals.
The innovative pumps fulfil very high quality standards. They are made entirely of stainless steel. The standard design of the twin screw pumps is a two spindle version. A left and a right-hand feed screw displaces the product in the axial direction. Unlike the working principle of the similar eccentric spiral pumps, where sometimes the rotor or stator must be replaced after a short time, twin screw pumps work with very little wear. The non-contact running screws are designed as very resistant to wear, therefore abrasion and wear are entirely avoided in the medium.
Since the product is not spun and then deflected in the direction of rotation as in centrifugal and rotary lobe pumps, the product conveying is performed particularly gently. Furthermore the pumps also work with extremely low pulsation to protect the conveyed material and the production plant.
Additional features of the twin screw pumps are their high suction power, which is accompanied by low NPSH values which therefore counteract cavitation. Not only the conveyance of low and high viscosity products - also with low gas content - is possible with the same pump, the CIP cleaning can also be performed with the same pump. This saves space and money because there is no requirement to install a second pump for CIP, which therefore reduces the effort and expense for measuring, regulating and pipework as well as valve engineering and cabling.
Hygienic twin screw pumps generally have an EHEDG hygiene certification, they are easy to dismantle and conveying lumpy goods up to 45 mm in diameter is not a problem. Double flow high-pressure twin screw pumps are available for differential pressures of up to 50 bar. Both the pump outlet as well as the two pump inlets are selectable with different nominal diameters to cover a performance range of up to 50 bar. That is especially important for the co-operation for pumps and heat exchangers and/or also filtration systems.
The position for the mechanical seal in all pump designs complies with the latest technical standards for design technology for pumps. They are positioned exactly in the flow area and are therefore excellently washed round, cooled and cleaned. The mechanical seals are robust and wear resistant and are single or double effective depending on their application. All elastomers which come into contact with the product are designed as FDA compliant shaped rings which considerably simplifies the cleaning process.
Hygienic twin screw pumps are predestined for demanding pumping tasks. They are utilised for many applications e.g. conveying cheese spread, pastes, viscous dough, meat emulsion, whole egg, frozen orange juice concentrate or yeast cultures. Twin screw pumps guarantee that creams, toothpaste, body lotions as well as also medicines can be supplied to the customer with excellent quality in the fields of body care products and pharmaceutical products.