The challenge

With production in Vlotho (Germany) and Suzhou (China), the purpose of the project was to increase the availability of the diaphragm at both production sites, but in particular at the factory in Suzhou, China, as the majority of the diaphragms would be required here in the future. At the same time, it was important to focus on the quality and the properties of the diaphragm. The main objective was to secure production and direct sales of the diaphragm in the destination country (China) at a competitive price and of a high quality, particularly with emphasis on the lifetime and the chemical resistance of the compound.

The process

The project was initiated with a thorough review of the requirement specifications of STÜBBE. During this process, we also selected and tested the suitable rubber qualities.

”After the initial meetings with STÜBBE, we started the development of a new rubber quality and built a test stand at AVK GUMMI for the purpose of testing the existing STÜBBE diaphragms as well as diaphragms produced in our own rubber quality,” says Carsten Bach Jensen, Sales Manager at AVK GUMMI, and adds: “We adjusted the mould and carried out a number of tests with emphasis on friction and wear resistance as well as the bonding between rubber and PTFE/fabric.”

STÜBBE has received test samples at regular intervals throughout the entire process and has shared the test results with AVK GUMMI. Furthermore, the required approvals (FDA 21 CFR 177.2600, Elastomer Guidelines (23 °C), W270, 3-A Sanitary Standards Class II) were obtained during the development phase.

The solution

”After several tests, the choice fell on AVK GUMMIs newly developed rubber quality, EXF-70,” says Hendrik Märker and continues: ”Compared with the test results of the existing diaphragms, the test results of the diaphragms produced in the new rubber quality were far better with respect to standard deviation and average lifetime. Therefore, there was no doubt as to whether or not we should carry out the change.”

The cooperation

”Our cooperation with AVK GUMMI has been very successful, both in relation to technical advice, quality assurance, durability and the optimisation of the project,” says Hendrik Märker and concludes: ”The project was more comprehensive than expected, but we have no doubt reached our goal and completed the project with a positive outcome. This means that we will definitely also consider AVK GUMMI in connection with future projects.“

STÜBBE GmbH & Co., KG, Germany

Diaphragm valve

STÜBBE is an international manufacturer of pumps, valves and instrumentation systems made of thermoplastics. 

With more than 60 years of competence in thermoplastic, STÜBBE has the expertise and experience to develop durable solutions for handling aggressive media in complex applications. The products are used across the world in the environmental technology, surface technology, chemical industry and metallurgy & mining. STÜBBE has production in Vlotho (Germany) and Suzhou (China).

It was important for STÜBBE to find a European cooperative partner with modern and high-qualitative production facilities and product development capabilities in Europe and Asia. Therefore, it was a great advantage that AVK GUMMI already had a factory in China
Hendrik Märker, International Purchasing Manager, STÜBBE GmbH & Co., KG