Hydroforming technology creates innovative diaphragm valve bodies


New tube valve body offers unique advantages over forged and cast bodies

Bürkert Fluid Control Systems has launched a completely new body type for diaphragm valves that is particularly aimed at applications in hygienic environments. The bodies, manufactured through the use of a patented manufacturing procedure - so-called hydroforming technology - satisfy the highest requirements imposed on materials and cleanability. With a lightweight, sustainable, and hygienic design the tube valve bodies are unique and compensate for the weaknesses of forged and cast valve bodies.

With the introduction of the new tube valve body, Bürkert completes its product line in the diaphragm valve area and presents a high-performance alternative to forged and cast valve bodies. The great benefit of the new housings is that they are manufactured from high-quality stainless steel tube, like the other plant or system lines. This enables hygienic tube-to-tube welding of virtually identical materials, through which a uniformly high quality of weld seams is ensured. Compared with cast bodies, in addition, neither cavities nor other defects occur in the manufacturing process, which means the risk of contamination is significantly minimised.

Through the processing of high-quality tubes in combination with hydroforming technology, it is possible to manufacture variants that are as much as 75% lighter than forged housings, which goes hand in hand with a great customer benefit. For example, through the reduced material used, the energy requirement and the heat-up or cooling phase duration of the plants are reduced during the cleaning or sterilisation processes. Thus energy costs are lowered and downtimes are reduced.

Moreover, the same housings enable optimised temperature control, easier process validation and shorter response times, as well as reduced installation costs, because supports are eliminated. In addition, the lightweight design of the housing has a positive effect from an ecological perspective. Thanks to the low mass, users profit from energy-savings by which the CO2 footprint is reduced in operation. The manufacturing process is also designed to be more environmentally-friendly. When manufacturing a DN 25 cast valve body, almost 7,000g of CO2 are released; the value for the new Bürkert tube valve body is just over 2,000g.

Specifically, for the hydroforming process, an ordinary stainless steel tube in pharmaceutical quality is filled with a water-oil emulsion and then charged with a high inner pressure. In this process the tube is formed into a valve body and simultaneously it is joined permanently to a flange. Afterwards, flange and tube are connected via laser welding to ensure the cleanability and stability of the product. A special annealing process to increase resistance follows. In the final step, precision surfaces of the highest quality are generated. The result is an innovative product in which a medium only comes into contact with a pharmaceutical-compatible tube and diaphragm.

Target applications of the new tube valve body are in the demanding markets of pharmaceuticals, biopharmaceuticals, cosmetics, as well as the food and beverage industry. From a technical, economic and ecological perspective, the valve bodies satisfy the current requirements and regulations of these markets. For example, they fulfill the globally established ASME-PBE standard regarding dimensions and tolerances, as well as the EHEDG requirements regarding hygienic design.

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For the market introduction the tube valve bodies are available in the welding connection sizes ½, ¾, 1, 1½ and 2 inches with the Bürkert diaphragm valve types 2031 and 3233.