Elastic metal C Ring in Cryogenic Valve HTMS High Tech Metal Seals
In this respect HDW (Howaldtswerke–Deutsche Werft GmbH) remembered the expertise and many enjoyable years of collaboration working with STÖHR Armaturen and commissioned Stöhr for the development and manufacture of a compact valve block. The novel design needed to take into account the special and challenging requirements of submarine construction and the expense of testing welded joints leading to lower costs for the shock test and other associated tests with the valve block concept.
It proved to be a difficult task as the particular requirements associated with the handling of oxygen also had to be met. During the filling stage, when the oxygen is in a liquid aggregate state, both the liquid and gas forms need to be taken into consideration for the extraction process. Liquid oxygen tends to oxidize and harden organic materials, altering the material substance and making it brittle. A sealing material capable of handling cryogenic temperatures at elevated pressures was required. The selected seal needed to maintain its sealing integrity at values <1.0 x 10 e-8 mbar*l/s, down to a temperature of minus 268°C. Replacement of the seal during maintenance of the valve block needed to be easy and thus eliminate the need to recondition the grooves of the valve.
With HTMS, High Tech Metal Seals from Belgium, Stöhr had found an experienced partner for metal seals able to assist their company in the development of a valve block that would replace the function of the individual valves, halving the space required and unit weight. This goal was achieved by reducing the number of medium contacting holes and optimising machinability.
The complexity of this task required the consecutive implementation of 3 High Performance HTMS seals.
The design and manufacturing know-how of Stöhr as well as the use of the Metal C-Sealing rings from HTMS ultimately produced the desired result - a valve block that saves on space, weight and test expenditure, and is advantageous in terms of safety and reliability. Thanks to their great enthusiasm and know-how in the field of valve technology, Stöhr Armaturen came up with an innovative and tailor-made solution. The resulting valve block, which is easy to assemble on the front side of the tank, has exceeded all expectations.
08 June 2010
