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ZWICK Armaturen GmbH

Ennepetal, Germany

Maximum Performance as the Norm

[ Published in HOERBIGER@MOTION 01/2013 ]

Over the course of more than 30 years, ZWICK Armaturen GmbH, located in Ennepetal, Germany, has made a name for itself internationally with butterfly and check valves, in particular for critical applications. The medium-sized family business in the southern Ruhr region is a typical example of companies that are leaders in their market niche. To maintain their edge, Hidden Champions like ZWICK continually look for new approaches to optimize the function and quality of their products. When it comes to butterfly valve actuators, ZWICK relies on HOERBIGER Automation Technology.

One of its most successful products is the triple offset butterfly valves of the TRI-CON series. These valves are in demand whenever high reliability and an absolutely leakproof design are key. On average, ZWICK manufactures 6,000 valves annually in nominal sizes ranging between DN 50 and DN 1800. The machinery is designed for components up to 2.2 meters in diameter (DN 2200). In addition to series production, one of the strengths of the family business is the capability to still offer the customer specialized solutions from made-to-order production.

First-rate engineering and state-of-the-art manufacturing methods make it possible. ZWICK has high-precision machine tools, which allow special components, such as the conical sealing element, the sealing disk and the stainless steel seat of an industrial valve, to be produced with very tight tolerances. Thanks to this production method, part of which is patented, the company can guarantee that its industrial, butterfly and check valves are 100% leakproof even under high nominal pressures up to 160 bar and temperatures up to a maximum of 815 degrees Celsius. A special feature of ZWICK valves is the sealed bearing. It makes it possible to reliably use the butterfly valves even in systems containing cracking and crystallizing substances. Materials such as stainless, duplex and super-duplex steels, titanium alloys such as Inconel, bronze and Hastelloy pose very high machining demands.

With the investment in two new production lines, ZWICK meets requests voiced by customers to receive even sophisticated valves and replacement parts more quickly than in the past. The new equipment is expected to reduce the machining time by 20 to 80 percent as compared to the production on individual machines. In order to be independent of potential bottlenecks in the supply of material, ZWICK stores approximately 1,000 tons of raw material at any given time. Even if ZWICK were forced to newly procure raw materials, the company operates significantly faster than others.

PART

ZWICK builds valves for the highest standards: the performance spectrum encompasses metal seated butterfly valves of the TRI-CON series, check valves of the TRI-CHECK series, and TRI-BLOCK, a redundant "double block and bleed" design. The most successful product is TRI-CON, in which an elliptical disk performs the sealing function. As a result of the floating, self-centering disk, the valve seals completely even during temperature fluctuations. Unlike other manufacturers, ZWICK does not produce the disks and housing in pairs, but manufactures them in a patented precision production operation as series components. It is not until they are assembled that an employee takes the components, which fit each other in terms of size, from inventory and combines them into a valve that is guaranteed 100 percent leakproof.

PART OF

ZWICK has been using electrohydraulic actuators made by HOERBIGER's Strategic Business Unit Automation Technology as drives for the safety-relevant applications of its best-selling TRI-CON product. A compelling feature of the self-sufficient and compact drive units is that they continue to operate even if the central oil supply should fail. Thanks to a spring set, the system switches to safety mode in the event of a failure in the power supply or hydraulic system. Another advantage of the compact power pack made by HOERBIGER is that the tank, pump and motor have been combined into a powerful functional unit: the valve manufacturer can install the electrohydraulic HOERBIGER actuator in the same way as an electric drive.

PARTNERSHIP

More than 30 years ago, today's ZWICK Armaturen GmbH became a contract manufacturer for industrial valves. Back then, valves used to control the engine exhaust gases of submarines were needed. ZWICK has developed valves on its own since 1997. And it has done so successfully: today, the company operates two locations in Germany and another in the USA. The employees produce process and control butterfly valves for power plants, refineries and the chemical and petrochemical industries. Its customer base also includes the shipbuilding industry as well as manufacturers of offshore equipment.