Fluid Power Journal

Case Study: Developing a Water-Hydraulic Process Valve


From Freudenberg Sealing Technologies.

Applications in the process industry make high demands on all components. The components must meet hygienic design specifications, be resistant to process media, and fulfill various conformity requirements.

And of course, this also applies to the seals. That is why the Danish manufacturer Hydract relied on Freudenberg Sealing Technologies’ development expertise to select effective sealing solutions for its new hygienic process valve.

Hydract, based in Holstebro, Denmark, specializes in innovative valve technologies for the liquid processing industry. Unlike conventional valves, Hydract relies on water instead of compressed air to power the valve actuator. Water is noncompressible and thus enables more precise control and improved mixing accuracy. A new hydraulically actuated process valve for a market-leading brewery was also based on this principle.

Beverage industry requirements

Specially designed to meet the needs of breweries and other hygienic liquid processing requirements, the patented process valve also required customized sealing solutions. Quite early in the development process, it became clear that standard seals could not meet the high requirements of the beverage industry. The valves used in the process industry must be able to meet high standards in terms of hygienic design specifications, receive industry-specific approvals, and resist cleaning media.

The developers turned to the experts at Freudenberg Sealing Technologies. They have already demonstrated their comprehensive know-how in this field with their product line for hygienic plants in the process industry.

The joint development work resulted in three food-approved seals: the hygienic pressure seal made of Quantum PTFE F18245 and 85 EPDM 302 in two sizes, a hygienic radial seal made of 85 EPDM 302, and a static seal in which two O-rings made of 85 EPDM 302 combine to form a sealing element. With a tailored hygienic design, all three seals offer high-pressure resistance from 5°C to 140 °C (41°F to 284°F), pressure resistance from 0 to 10 bar (0 to 145 psi), and a long service life. The premium quality materials used have received the relevant approvals and were subjected to the conformity tests according to EG (Reg.) 1935/2004, EU (Reg.) 10/2011, FDA, and 3-A sanitary standards.

Test bench trials

The joint development project showed that customized sealing solutions can also be developed in a timely and cost-effective manner. As a basis for further development steps, the team at first tested three of the new hydraulic process valves on Freudenberg’s in-house test bench. This enabled the necessary design adjustments for optimal service life to be identified and minor changes affecting installation and geometry to be implemented directly. The sample seals for the various test bench trials were produced without tools and thus with considerable cost and time benefits. This was made possible by the Freudenberg Xpress service, which offers machined seals made from original materials and original profiles for prototypes, spare parts, or economical small series. Special machining and milling techniques enable individual designs to be realized precisely.

The close cooperation between Freudenberg and Hydract resulted in three high-performance sealing solutions that are fully functional over a long service life, even under demanding test conditions. They offer very good resistance to extreme pressures, meet hygienic design standards, and thus have ideal properties for use in the beverage industry.

For more information, visit www.fst.com.

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