Work was completed earlier this year (2014) on the new 382m² half-million pound extension to the manufacturing area of the Centa Transmissions factory in Shipley, West Yorkshire, which has enabled Centa to restructure the entire production and warehousing facilities within the factory. In turn, this has resulted in an increase in output and efficiency that is impacting positively on the business.
Centa’s managing director, Bob Arnott, says:
“The new building has given us the extra space we needed for expansion and we have installed three new machines to make a new production cell. The comprehensive factory re-organisation means that the company, which has seen sales increase over the last three years, is set for further significant growth over the coming months.”
Two new lathes, the ST740 and the ST30, along with a new and larger VF3YT machining centre, has given Centa the ability to not only produce more work in house, but to now manufacture components of up to 660mm diameter on site. This means that some of the work previously outsourced is now being produced in Shipley, the result being greater control, profitability and efficiency.
The expansion of the factory has also seen some new faces joining the Centa team, with two graduate engineer positions being made permanent in the design team, Gary Middleton coming in as production controller and Tom Binns as a sales engineer with responsibility for London and the South East of England.
Centa is also building on its expertise in the elimination of vibration and noise caused by misalignment and is a leader in carbon fibre shafting, whether as a lightweight, short shaft where weight reduction is the objective, or to cover long-span marine drives. Foremost in this area is their highly versatile and super-lightweight CENTADISC-C composite coupling and carbon fibre shaft, which is designed to span distances of 6 metres, without the need for intermediate bearing support. Longer shafts are bespoke and will be designed to ship specification. All can be provided to various levels of classification, for example, ABS, DNV, etc.
Very often it’s the support bearings on long shafts that cause misalignment problems as they do not allow for flexibility in the ships structure, their rigidity restricting shaft movement which in turn, causes vibration. This vibration then results in excessive noise and premature wear on the drive components. That’s why the specification of a long, super-strong tubular shaft, which does not rely on intermediate support, results in a quiet, efficient and highly reliable marine transmission system.
Initially created to save weight in fast ferries, offshore support vessels and workboats are now using hollow composite shafts. For example, carbon fibre shafts were installed on a number of Delta ARRC boats built for petroleum company BP, with twin 1000bhp CAT engines, 3 section CD shafts and aluminium housing cooper bearings acting as watertight bulkhead seals. These are 7.8m long weighing 138 kg for the entire shaftline.
“The benefits of carbon fibre shafts are numerous, Arnott, says, They are typically 70% lighter than solid steel shafts and employ flexible couplings to eliminate stress on the drive components. They also enable higher speeds to be achieved and allow marine engineers to span ever greater distances without bearing support. This results in fewer bearings and pedestals, less noise, more power and quicker and easier installation.”
Tubes, in general, have a better stiffness to weight ratio and with lower weight tubes engineers benefit from faster rotation, or longer spans with more torque. Consequently, the larger the diameter of the tube the better the weight to stiffness ratio will be, resulting in a smoother, more economical drive system.
Carbon fibre shafts for new build ships are no more expensive than conventional steel installations because you save on bearings, support structures; temperature monitoring and installation times. In effect, the designer can engineer a tube specifically for the application based on length, speed and power transmission, removing any redundant weight common in steel shafting.”
In situations where there is a requirement for a long span drive, the use of a carbon fibre shaft provides the perfect solution, particularly in the hull of large catamarans with staggered engines. These shafts also allow placement of large engines further forward in the vessel, transferring the centre of gravity to a more favourable position, for example, in luxury super yachts, ferries, workboats and other marine craft.
In practice, this means that where a distance of several metres would have previously been bridged using flexible couplings and a steel shaft supported by multiple pillow blocks, a lightweight carbon fibre shaft will ‘hang’ freely between engine and gearbox, unimpeded by supports and with its flexible connections acting as a double cardanic joint.
Other benefits of utilising a long carbon fibre shaft are that they integrate well within the increasingly flexible hulls of modern vessels, particularly aluminium; they require minimal maintenance and provide a robust, torsionally stiff, corrosion resistant and sound absorbing answer to transmission vibration and noise; as well as compensating for axial, radial and angular misalignment.
Centa’s carbon fibre shafts with CENTADISC-C have been available for seven years and the company is now seeing increased demand for carbon fibre shaft solutions for their weight saving capacity. For example, Port of London likes the fact that maintenance issues are vastly reduced and problems relating to corrosion are eliminated.
“Centa’s design and tube construction philosophy is based meeting the growing trend for super-strong shafts, combining ever-greater spans and lower weight, whether it’s of a steel or carbon fibre construction.”
This and the vastly increased capacity at the Shipley works, means customers of Centa, a company at the forefront of marine power transmissions development in the UK, are already benefiting from the service they receive.
To complement their range of flexible couplings and shafts, Centa offers a wide range of gearboxes that meet the demands of the marine industry and from 600 tonnes down to Ø22mm, their gears providing versatile solutions to all types of drive problems. Centa also has the ability to provide gear sets/gearboxes for ‘Pod Drives’, irrespective of size or power.
As the official UK distributor for Kumera Norgear, Centa provides gearboxes and speed reducers for fire-fighting pumps, electrical and hydraulic power supplies and thruster propellers for all types of craft.