Spraybake Limited has recently completed a major upgrade to a 28m long rail vehicle paint spray and bake booth, which has been in daily use since 1996. The booth was first installed for Rail Care at Wolverton Railway Works.
Wolverton railway works, known locally as Wolverton Works or just The Works, was established in Wolverton, Buckinghamshire, by the London and Birmingham Railway Company in 1838 at the midpoint of the 112 miles long route from London to Birmingham.
‘The Works’ is now operated by Knorr-Bremse as one of its two UK Rail Services facilities. This facility, ideally placed to serve customers located in London and the south of the UK, has the capability and capacity to carry out service, maintenance, repair, overhaul and upgrades on all train types.
The Knorr-Bremse Group, with its head office in Munich Germany is the world’s leading manufacturer of braking systems for rail vehicles. They also provide services to rail operators throughout the world for the repair and upgrade of rail passenger vehicles. Knorr-Bremse is renowned for exacting high standards on quality control and finish required for upgraded rail vehicles.
To meet the high standards of paint finish and durability required by Knorr-Bremse, Spraybake were tasked to offer technical solutions that would provide the following:
• Minimal temperature variations within the spray booth during the paint application and drying process.
• Rapid rise in temperature to allow painting within minutes of first start-up during the coldest winter period.
• Reduction in process times after paint application. Rapid drying of paint to facilitate greater production through the spray booth.
• Data logging of each paint job of temperature and humidity, process time and reporting the exact consumption of electricity and gas.
• Automatic control of main fan speed for accurate mandatory pressure monitoring within the spray booth.
• Improvement to lighting within the spray booth.
Spraybake were contracted by Knorr-Bremse and undertook the following work:
• Spraybake installed the own designed and renowned, “Enhanced Curing System,” comprising of a series of high velocity air delivery nozzles which were installed in the ceiling and at each end of the spray booth. A direct drive centrifugal fan system deliverers filtered, heated air through the nozzles at up to 10m/s. This system is used during the flash-off and drying process providing an excellent mix of air and heat thereby eliminating the previous problems of significant temperature variations.
• Installed new direct-fired Midco heating system. With minimal moving parts the Midco is highly reliable and is the most energy cost efficient burner available. From cold the Spraybake Unit is available at a constant 20 degsc within 6 minutes from start up.
• The use of the ‘Enhanced Curing System’ during the flash-off and drying process reduces process times by up to 40%. Energy usage is also reduced by up to 40%. Significantly, the enhanced process time allows an increase of the number of rail vehicles painted. Projected increase in throughput is expected to exceed 35%.
• To meet the requirements of Knorr-Bremse Quality Control, Spraybake installed a Supervisory Control and Data Acquisition System (SCADA). This computer system is used for gathering and analysing real time data for temperature, humidity, temperature variation and the consumption of gas and electricity used against each identified rail vehicle. Using the true cost that Knorr-Bremse pays for gas and electricity the system provides a visual display of the monetary value of energy used during each process. This is provided to heighten the awareness of the operators to the true energy cost involved in painting of each rail vehicle.
• Spraybake installed Variable Speed Drive control (VSD’s) to each of the main air inlet and extract fans. Utilising a pressure transducer system the main fans are controlled by the VSD’s to maintain a marginally negative pressure at all times during the paint and drying process. This is required under COSHH Regulations. Not only does this system provide fully automatic control of booth pressure it also warns the operators of the imminent shutdown of the booth when extract paint arrester filters become blocked.
The use of VSD’s is a properly engineered solution to controlling booth pressure and eliminates the need for in-duct dampers and manual/motor driven adjustment. Reduction in electrical consumption can be up to 40% annually. A new Programmable Logic Controller (PLC) was installed in the main control panel. This allowed the control integration of the new Enhanced Curing System and the automatic pressure monitoring of the booth.
• Spraybake upgraded the lighting system to provide a minimum of 1200 lux at one metre above the floor of the booth. Operators now enjoy virtually shadow free conditions when applying paint, allowing maintenance of the paint edge on large flat surfaces.
The work was completed to the agreed schedule of works. Knorr-Bremse has indicated their complete satisfaction with project.