New technology for hygienic and aseptic control valve applications in small volume dosing.

The requirements for hygienic and operational safety in the pharmaceutical, biotechnology and the food and beverage industries are continuously increasing. In order to fulfil the requirements and the associated customer requirements, GEMÜ has developed the PD design (plug diaphragm) to combine the advantages of diaphragm valves with regard to cleanability with the advantages of globe valves with regard to controllability.

A diaphragm valve (see figure 1 Gemü 650 Diaphragm Valve) is the first choice when a valve is needed that is easy to clean and suitable for CIP and SIP processes. Diaphragm valves can also be used to implement rough control applications, provided that the desired flow rates are large enough. However, if a fine batch is required or a large control range must be covered, diaphragm valves soon reach their limits. Globe valves (see figure 2 Gemü 530 Globe Valve) with flow restrictors may be precise control valves, but they are anything but aseptic. Due to the so-called lift effect on the spindle, medium is transported into the gland packing and is not removed during plant cleaning, which can lead to the accumulation of dirt particles in this area and/or the multiplication of bacteria.

In order to avoid this, bellows made from PTFE or stainless steel are often used as actuator seals. But with this design solution too, medium can be deposited between the folds of the bellows.

For the GEMÜ 567 BioStar aseptic control valve, a new approach was therefore adopted to achieve the hermetic separation of the medium from the actuator while simultaneously achieving very good valve control characteristics. The separation of the area conveying the medium from the actuator was implemented through a newly developed PTFE diaphragm and the automatic control solution through a parabolic plug (see figure 3 Gemü 567 Biostar Aseptic Control Valve). The basis for this was the GEMÜ PD design (plug diaphragm). The advantages of the plug diaphragms and the angle valve body are cleanability and the cavity geometry. This makes the valve a suitable control valve for aseptic areas and most similar applications.

With the newly developed GEMÜ PD design, the GEMÜ 567 BioStar aseptic control valve offers the option of precisely controlling the addition of small volumes in the range of 80 l/h to 4100 l/h in aseptic conditions in the pharmaceutical industry, the biotechnology industry, as well as the food and beverage industries. This opens up versatile aseptic applications, such as the highly precise dosing and automatic controlling of trace elements, additives, growth substances, flavourings or dyes, the preparation of biocultures, pressure control for WFI systems, aseptic tanks and fermenters. It can also be used in the manufacture of beverages, e.g. for the carbonation of beer and mineral water. Another possible application is in the production of foods, for example in analysers and in-line mixing systems. In conclusion it can be said that the GEMÜ 567 BioStar control valve opens up countless options for control in aseptic and hygienic applications.

The GEMÜ 567 BioStar is available in sizes from DN8 to DN20, with various connections and actuators. Approvals include FDA, USP Class VI and ATEX.