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Multi couplings improve productivity & safety

14 March 2014

Stäubli multi-couplings provide the secure, automatic, leak free connections operating at the heart of Perkins impressive engine testing facilities at their Peterborough factory.

For well over 75 years, Perkins has led the field in the design and manufacture of high-performance diesel engines. A programme of continuous development, allows the company to offer one of the most advanced and comprehensive ranges. Acquired by Caterpillar in 1998, together they are the world’s largest diesel engine manufacturer, supplying major equipment manufacturers in the construction, power generation, materials handling, agricultural and general industrial markets.

Perkins prides itself on hot testing every engine it produces (it also cold tests each engine too!). This requires a bank of test cells where the engine can be connected to coolant, fuel, oil, electrics and an exhaust line which allows each engine to be run up to the designed speed. Perkins operated no less than 68 engine test beds, each one manually operated, calling for laborious and slow connections to be made to each engine. Health and safety of operatives and environmental aspects were also a concern in the cells with the risk of hot oil escaping and the chance of a fire in the confined space of the test bed – a new safer and automated solution was required.

Perkins embarked on a project to replace its existing engine test facilities with new state-of-the-art automated systems that provided a clean working environment, eliminated any chance of environmental harm and would be capable of accommodating the growing production volumes on the 4 litre and 6 litre engine lines. In total the project was a £25 million investment.

Essential to the new system was automating the connections required by each engine, removing any chance of poor or incorrect connections and eliminating any leaks. The new cells also had to to be able to test and monitor the electrical systems increasingly being used on diesel engines and provide data sets for each engine that could be accessed, analysed and supplied to the customer when required.

This project was the largest upgrade implemented at the Peterborough plant and called for a top quality facility, flexible enough to cope with the numerous variations in equipment and layout being applied to the standard engine design. When planning the connections, previous good working experience of using Stäubli mono connectors made it natural to involve Stäubli in this multi coupling application too.

Stäubli analysed the connection requirements and recommended using tailored sets of multi-coupling plates with the socket side located on the engine test cradles and the plug side on the test beds. Similar solutions had been produced by Stäubli for use in the motorsport sector as well as being extensively used in the automotive market for example by Renault at their Cleon factory in France.

Assembling an array of quick release connectors onto a single multi-coupling plate provides quick and simultaneous connection of all services e.g. coolant, oil, fuel, pressure transducers, electrics and data. It is the most significant single improvement in productivity that can be applied to engine test beds.

Stäubli MCS multi-couplings are configured for each specific application. Experienced Stäubli engineers review requirements to determine the precise specification for the plate. This takes into account the type of fluids in use, their pressure and temperature as well as the electrical connections (amperage, voltage, number of pins etc.) required and the type of valving and seals needed and the size envelope available and positioning on the unit. Wide experience in the connection of fluids and gases and the facility to incorporate and develop electrical connections with  sister company, Multi-Contact, places Stäubli in a unique position, able to supply full function multi-coupling solutions.

From this data Stäubli designs and manufactures a specific multi-coupling plate drawing on products from its wide range. This will include modular quick release couplings and electrical connectors, guiding and centring components as well as connection and locking systems. Extra connectors can be added to give spare capacity or to allow for future modifications. In the Perkins application Stäubli SPH series connectors were selected for the fluid lines and REA series for the electrical connections.

The use of multi-couplings dramatically improves safety as well as productivity. Clean break connectors ensure no loss of fluid or ingress of contamination on disconnection and help maintain a clean and safer working environment. Connection can only be made in one position, eliminating any risk of circuit inversion and mis-connection. Guidance pins on the multi-coupling ensure that the engine is located precisely in the correct position on the test bed. Inclusion of the electrical connections on the plate removes any tangle of leads around the engine that can often be a problem.

The 68 manual test beds at Perkins were replaced with 12 cells on the 4 litre line using 52 engine pallets. The productivity of the test beds improved dramatically. Production levels of 125,000 engines/year calls for a testing rate of 37 per hour – a rate easily achieved by the new facility. Floor to floor times for each engine through testing are now of the order of 15 mins compared with hours on the old system and the working environment and safety aspects have been improved out of all recognition.

Some of the engine pallets have now been operating through the test cells for several years, testing close on 1 million engines, Stӓubli’s connectors have operated faultlessly.

The test facility has performed so well that a similar system on the 6 litre engine line has been installed. Six test cells and 20 test pallets have each been equipped with Stäubli multi coupling plates, capable of testing the increasing production volumes of engines.

Frank Perkins who started the company would approve; his motto was ‘Where there is no vision the people perish’ certainly vision was essential to the objective of producing a world best engine test facility at Peterborough; Stäubli multi couplings have played a vital part in bringing this vision to reality.