For special use

Slip rings or electrical rotary transmitters make it possible to transmit signals and electrical power from a fixed to a mobile structure. However, if liquid or gaseous substances are also to be transferred, more sophisticated solutions are necessary. With its combined rotary connectors, Servotecnica offers a range of systems that can be individually adapted to the respective application.

Servotecnica GmbH develops and manufactures electrical rotary joints for every application. They can be used for various types of signals in a wide variety of industrial applications. As a partner in mechanical engineering, the company based in Raunheim (Rhein-Main area) has decades of experience. With series such as "Capsule", "Faston" or "Through-Bore", it has a wide range of slip ring series for a wide variety of applications - from machine tool construction to the packaging sector and the medical and pharmaceutical industries to the wind energy sector. The aim of Servotecnica is to deliver reliable components with an optimal ratio of quality and price - if required also in a robust steel housing with a high degree of protection for the oil and gas industry as well as the offshore sector.

The most important function of an electrical rotary transmitter or slip ring is to transmit signals or electrical power from a fixed to a mobile structure in order to enable continuous rotation between both sides. Slip rings therefore consist of an external stator, which is usually fixed, and an internal rotor. The permanent conductive contact is made during rotation by precious metal brushes in the stator, which rub against precious metal rings on the rotor. Servotecnica slip rings achieve a service life of up to 50 million revolutions.

Liquid connector and rotary joint combined

With its combined rotary joints or rotary connectors (also known under the terms combined slip ring, electrical rotary connector and fluid rotary connector or fluid rotary joint), the manufacturer offers solutions that allow liquids, liquid substances or gases to be transported from a fixed to a mobile structure. The combined rotary joints or rotary connectors are produced and sold by Servotecnica itself. The integrated fluid connectors, on the other hand, come from the US partner DSTI.

There can be several passages for transmission. Depending on the liquid or gas, appropriate sealing materials are used for each application. Slip rings are used for the electrical signals. The stator consists of precious metal brushes (gold-plated or silver-plated copper), while the rotor is made up of rings made with precious metal. The mode of operation is reversible: the normally fixed outer part can be made to rotate and the - normally rotating - inner part can therefore be held in place.

Demanding use on the high seas and in food production

An example of applications in which combined rotary joints are used are cable drums for offshore applications. Depending on the application, this must transmit electrical power, signals and data from the rotating drum to the stationary part. Fiber optic cables are often used here. In the case of more complex cable drums, such as those that are the rule in container ports or on oil platforms, gases and fluids must be transported in addition to the electrical signals. This is where the specially designed rotary joints are used, which are combined with slip rings - also ATEX-certified, if required - to form a compact unit.

Another very demanding application example are filling systems for food or beverages or pharmaceutical products in a sterile environment. Here it is important to meet certain basic requirements such as resistance to cleaning agents or a high level of impermeability. In beverage filling systems, the combined rotary joint enables the bottles to be cleaned with detergent and water, blown out with compressed air and refilled with the appropriate liquids. At the same time, the data from various sensors must be passed on to monitor the processes.

Wide range of rotary connector designs

Servotecnica offers a range of different combined rotary joints. The simplest solution is the SVTS C 05 version with a single air passage of 6 or 10 mm. The electrical part of the rotary joint can transmit power, with contacts with up to 15A and up to 24 passages, as well as digital and / or analog signals or field buses.

If a larger number of air passages with pressures of up to 40 bar is required, we recommend combining the LT pneumatic transmitter with one of the SVTS A type electrical slip rings. The LT21241 version offers 24 air passages and 56 electrical power signals and / or signals including field buses.

The SE series with 2 to 24 passages in seven gradations is the right solution for very high gas pressure and small installation space. This achieves up to 512 bar at 300 rpm. For higher speeds of up to 500 rpm and pressures of up to 512 bar, the liquid rotary connector series GP with 2-3-4-6-8-10-12 passages with connections up to 1 “is recommended.

Perfectly adapted to the requirements

The GPS series with steel housing is suitable for solutions that require both air and liquid passages. With the GPS-301-12 version, up to twelve passes with pressures of up to 512 bar are possible - always provided that it can be combined with an electrical slip ring or rotary joint that allows the transmission of power, signals and fieldbuses. For each series, Servotecnica also offers solutions specially adapted to the individual application. In this way, the manufacturer can meet every requirement in the area of ​​combined rotary connectors.

By Christian Becker, Managing Director of Servotecnica, Raunheim