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Custom-made drive techniques for catering chains

18.07.2018

Heat-resistant and robust drives made by Groschopp

Grilled chickens, turning slowly on a skewer, are a feast for sore eyes and a culinary delight. Using modern techniques, these flexibly applicable rotisseries, manufactured by UBERT, make this culinary delight possible. However, very special demands are placed on such applied drive techniques - for these systems have to be especially heat-resistant, easy to clean and resistant to aggressive cleaning agents, which is no problem for Groschopp:    any technical requirement is mastered with individual and custom-tailored solutions developed by the experts of Groschopp-drives.

Ever since the foundation of the enterprise in 1965, the company UBERT GASTROTECHNIK GMBH is involved in the techniques for catering chains. The enterprise provides their equipment worldwide for fast-food-restaurants, snack bars, super-markets, petrol stations and leisure parks. UBERT not only offers single units for this target group, but also ready-for-use master plans; if requested, their experts take on the entire planning of the equipment, including the production and assembly. Even numerous customer-specific solutions are  implemented.

Ever since fast-food-chains have begun to conquer the world, UBERT as a pioneer has been involved in active participation in the creation of this branch. By doing so, the current technologies continue to be further developed, while completely new areas of applications are  unlocked. The company utilises fully-automated and computer-controlled processing centres in their production. High-power laser-, die-cutting- and metal-forming-techniques, as well as high-speed-bending automats ensure that the equipment, manufactured for the gastronomy, conform to the highest standards.

High Quality, made-to-measure

Additionally purchased components must also conform to these high quality-standards, e.g. the drive techniques produced by Groschopp which are used in a variety of rotisseries. UBERT has collaborated with Groschopp for more than 20 years. Naturally, there is a very good reason for such long-standing customer loyalty: "Then, as well as today, Groschopp offers high-quality products at a good price-performance ratio", maintains Christoph Stephan, Head of Design and Development at UBERT. "Especially for our rotisseries, due to the high operational temperatures and the regular cleaning necessary for the equipment, very special demands arise in respect of its drive techniques. Groschopp flexibly adapts all drive solutions to suit these technical requirements."

The special focus of our enterprise is on innovative motors and reducer gears, which are tailored to suit the systems of our customers. Any special request made is gladly implemented: for example, one gear-motor, designed for a rotisserie-series made by UBERT, was furnished with a special dip-coating in order to protect it against splash water during thorough cleaning. Generally speaking, almost all products that Groschopp deliveres to UBERT are of made-to-measure special design, necessitated by the extreme operational conditions. Motors have to be equipped, among other conditions, with a special winding due to the high oven temperatures, in order to guarantee a reliable operation and a long life-span.

Well-thought-out drive technique for the 'All-rounder'

Groschopp developed, for instance, an individual drive system for the rotisserie-series RT608, which is a component of the 'Convex Kombi-Towers CKT2000' made by UBERT. This combines rotisserie and steamer in one equipment – saving space and eliminating unnecessary long transport ways. The 'Kombi-Tower' is armed with three different heating systems for every occasion: infrared makes possible an optimal browning; convection guarantees a quick and all-through cooking, while steam makes for juicy products. Made-to-measure motors and reducer gears made by Groschopp are inserted in our rotisseries; their rotary drives allow a rotation around a shared, horizontally positioned centre-axle of up to eight skewers equipped with items to be grilled. This serves for a uniformity of the cooking, allows the meat juice and fat to drip down onto the respective next skewer, and in that way, ensures for a juicy grill-result: crispy on the outside, juicy on the inside. Furthermore, the optically displayed rotation supports the attractiveness of the grilling procedure and stimulates impulse buying.


"Our requirements put onto any drive solution demand first and foremost a sufficiently strong torque as well as heat resistance of up to approx. 60° C ambient temperature", says Stephan. By means of CAD-drawings of the rotisserie, Groschopp develops a drive system that is individually tailored for the application; it comprises a fan-cooled induction-skeleton-motor combined with a two-step reducer gear.

Special Motor, High-Powered Cooling

The compact, multi-pole, single-phase squirrel-cage induction motor with 20 Watts output is designed for various voltages in order to enable their application worldwide. The motor-winding is tailored individually to suit the application: In that way, strong vibration of the metal-sheet chassis is prevented. In addition, in such a robust environment, the International Insulation Class IP F, combined with a built-in thermoprotector, ensures a trouble-free operation even at high ambient temperatures.

The ingenious ventilation is naturally another factor, guaranteeing an optimal cooling by means of a special combination and an exactly defined routeing of air flow. The fan, positioned at the bottom of the drive, causes an upward current, leading heat away from motor and reducer gear, which is allowed to escape through louvres at the top of the equipment. The temperature values have been proven to be so good that the appliances were certified in  conforming to strict UL-specifications and, therefore, have been permitted for the American market as well. Any necessary thermal measurements of the motor drives under operation have been conducted by Groschopp.

Robust and Heat-resisting Reducer Gear

The reducer gear's ratio is i = 495:1, and is designed for a maximum torque of  3,000 Ncm.  The first transmission ratio is a worm-, the second a spurwheel-combination, which has been designed in a fortified way due to the higher torque-load. The possibility of an unequal loading of the grill was taken into consideration, which could cause impact stress: our special motor/reducer gear-combination is optimally laid out for such an event. "We were able to absorb such impact stresses by strenghtening the spurwheel", maintains Groschopp.

The extremely high operational temperatures were taken into consideration when designing the reducer gear; for temperatures can be as high as 280° C inside the grilling area. Although the drive unit is spatially separated by insulation, the generated heat can nevertheless be transmitted partly, which could have an impact on the reducer gear. All these factors have been taken into consideration in chosing the correct sealing elements as well as the lubrication solvent: sealing elements are made of heat-resistant silicone; a special, low- viscosity grease for gears, suitable for high load and high temperatures, has been chosen as lubrication solvent.

"The rotisserie RT608 serves as a  good example for the way, Groschopp meticulously plans and executes their drive solutions for our requirements", says Stephan. "Our cooperation is affected by our mutual understanding for the requirements and interests of each other, and it is characterized by an excellent basis of mutual trust." UBERT is highly pleased with all individual drive solutions supplied by Groschopp – hence, nothing can be seen that would stand in the way of the next 20 years cooperation.

 

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