PUMPS – In the creation of a high vacuum, oil-free membrane pumps provide the necessary fore-vacuum and turbo pumps perform the final compression. High-quality metal connecting components provide for reliable and permanently leak-proof connections in this process.

For more than half a century, VACUUBRAND GMBH + CO KG, located in the North Baden city of Wertheim, has specialised in technology for the generation of vacuums. The product spectrum includes, for example, rotary vane pumps, oil-free membrane pumps and entire vacuum pump stands. Vacuum pumps are used in laboratories, industrial applications or for leak detection, to name just a few. The top priorities at VACUUBRAND are functionality and, above all, quality: After several years of continuous operation, a VACUUBRAND pump should function just as reliably and smoothly as on the first day.

Especially the membranes, thanks to their oil-free operating principle, very high running smoothness and long life, open up a broad spectrum of applications. The MD 1 membrane pump introduced in the year 2000 has become very popular. Several thousand of these pumps have been built so far, which is a considerable number for the mid-sized company. Their primary area of use is to create fore-vacuum for turbomolecular pumps. High vacuum is needed for numerous applications, but the pumps needed for this cannot seal against atmospheric pressure. A fore-vacuum pump is always needed to provide the necessary pressure level. The turbo pump compresses for example from 10-6 millibar to approximately two millibar, while the MD 1 membrane pump takes care of the step between two and 1,000 millibar, i.e. atmospheric pressure. It is used for example as highly reliable OEM equipment in small turbo pump stands, which are used universally in research and analysis.

Leak detection devices are another typical application. They are used in the semiconductor industry, the manufacture of flatscreen monitors, the coating of eyeglasses or the production of lamps. These production processes take place under vacuum or in a defined process gas atmosphere. The systems have to be absolutely leak-proof. Leak detection devices operate with high vacuum. In many devices, the reliable and compact MD 1 is used as a membrane pump for the fore-vacuum.

Vacuum has to be of high quality

For such demanding vacuum processes, VACUUBRAND requires quality down to the smallest detail. This also applies to the pneumatic connection components, for which the company uses connecting components from Eisele Pneumatics GmbH + Co KG in Waiblingen. They are also included as OEM parts in the CAD construction kit of the vacuum specialist, so that the design engineers have easy access to the Eisele components for all VACUUBRAND products. Eisele provides detailed documentation of its components, which of course considerably facilitates the design engineer’s selection and use of the right threaded connections. Thanks to the broad product assortment, virtually all required components are available from one source. The high-quality parts from the Eisele modular kit can easily be modified to create specific customer solutions, for example by turning an additional face or adding a threaded joint. Eisele is always the right address when it comes to implementing special customised solutions. Currently, the company has 2,000 of these to offer.

The connecting components are installed on the outside of the MD 1 and therefore have to withstand not only the vacuum, but also all environmental influences. Eisele threaded connections made of anodised aluminium and brass are used in non-corrosive vacuum applications, where they have withstood the test of time for many years. The swivel screw fittings for the MD 1 with pre-mounted sealing rings are delivered by Eisele pre-assembled and ready for mounting. For corrosive applications, for example in chemical analysis, VACUUBRAND manufactures its own injection moulded parts from ETFE.

Pumps like the MD 1 remain in use for many years, which is why model maintenance and long-term supply of replacement parts are especially important. Here again Eisele is the right partner with its quality standard “Made in Germany”. The MD 1 features high performance and a lightweight and compact design. Its pumping capacity per weight clearly sets it apart from the competition, which is especially important for installation situations. The MD 1 is available as an OEM and built-in pump in different actuating versions, for example as MD 1 Vario-SP. Another quality characteristic is the low noise level throughout many years of operation. Users in analytical labs or research facilities appreciate that.

Special requirements fulfilled

The sealing requirements for vacuum applications are much higher than in normal pneumatic applications, in which a certain leakage rate, although not desirable, can at least be tolerated. In vacuum applications, even small leaks would endanger the entire process, since the required end vacuum could not be achieved reliably and stably. That is exactly why the connections and fittings have to fulfil high requirements. A clear advantage of Eisele quality becomes obvious here: All surfaces are extremely smooth and free of burrs, and all sealing surfaces feature a very high degree of plane parallelism, which prevents the occurrence of incorrect positions during tightening. Another decisive advantage of the Eisele system is that the hose connections are threaded instead of plug-in connections. Otherwise, the connections of the external hoses would be too easy to disconnect. They could be pulled off accidentally, for example. That is why a permanent yet easy-to-install connection system is the best solution for VACUUBRAND. Sealing against vacuum leakage can therefore be ensured over many years, even at high temperatures.

Dr. Jürgen Dirscherl, Technical Director at VACUUBRAND, appreciates the long-term cooperation with Eisele: “In matters of connecting components Eisele is an optimal supplier for the design engineer.”