Diaphragm valve
Diaphragm valves are a way of controlling fluids ( gases , steam , liquids ). In particular, highly viscous and / or highly adhesive media are distributed or dosed with it, for example. With other valve principles such as seat valves, some of these fluids would be deposited in the valve body. In the worst case, there could be cross contamination . That is why valves based on the membrane principle are also referred to as the principle of operation with the least dead space. Diaphragm valves with certain body materials and qualities are therefore often to be found in pharmaceutical and biotechnology systems , as any cross-contamination is to be prevented here.
However, other processes are also preferably implemented with membrane valves. Since different colors are used in painting systems or systems for the production of printer cartridges, it must be ensured here, for example, that the next color does not mix with the previous one. In the case of highly adhesive fluids of this type, this can best be achieved with aseptic valves.
In addition to the aspect of low dead space, diaphragm valves must also be designed and installed with optimized drainage to enable residue-free removal of the medium. For optimal emptying, there are various empirical values with regard to the suitable angle for installation in the pipeline .
Bar design
The membrane seals the valve on the sealing bar. For this purpose, the membrane is only moved over a relatively small distance by means of a pressure piece. The sealing ridge comes towards the membrane. The membrane only needs to be deformed slightly to open the valve completely. The operating medium only touches the membrane surface, all mechanical parts are outside of the media-wetted area. This type is made of plastic and metal. The direction of flow is arbitrary.
Areas of application: Use with high-purity (HP and sterile application) to heavily contaminated liquid, gaseous, neutral and aggressive media. Depending on the version, the application limits are 10 bar operating pressure and 150 ° C operating temperature, the flow characteristics are favorable. However, depending on the design, operating pressures of up to 20 bar can also be achieved.
Special features and advantages: All mechanical components are outside of the media-wetted area. The operating medium only touches the inner surface of the valve body and the surface of the shut-off diaphragm. With pneumatic actuation, the valve is also suitable for increased switching changes. When the valve is open, the pipe sections located behind can be emptied as much as possible by using appropriate installation angles.
Exemplary areas of application: Pharmacy, hygiene and sterile technology, semiconductor and microchip production, all areas of water treatment such as sewage, waste water, seawater, cooling water and utility as well as ultrapure and pharmaceutical water, sludge, powder and dust, cellulose and paper production / processing, paint and varnish production / processing, mining and mining technology, precious stone, metal and mineral extraction / processing, fertilizer production, gypsum, cement, sulfur and lime extraction, brine technology, sewage treatment technology, granulate production, mechanical and plant engineering , Automation technology, food and beverage technology.
Low seat design
These valves, on the other hand, do not have a sealing web, so that these are not diaphragm valves in the sense of standardization. However, they are still popular due to their robustness. Exemplary areas of application: Heavily polluted waste water, cellulose and paper production / processing, mining and mining technology, precious stone, metal and mineral extraction / processing, fertilizer production, gypsum, cement, sulfur and lime extraction / processing, sewage treatment technology and granulate production.
Norms
Almost all European manufacturers and distributors of valves orient themselves towards or meet the applicable standards with their web seat diaphragm valves. For diaphragm fittings made of metal, this is, for example, the DIN standard EN 13397.
Individual evidence
- ↑ Ralph Kroupa: Practical Manual Industrial Valves 2003 . Ed .: Ralph-Harry Klaer, Wolfgang Mönning. Vulkan, 2003, p. 67 ( limited preview in Google Book search).
- ↑ Valves for a filling system for printer cartridges at chemietechnik.de
- ↑ Theoretically determined angle of rotation for installation in horizontal pipelines (PDF)
- ↑ DIN EN 13397 industrial valves - diaphragm valves made of metal