Water purification systems play a key role in the production of multimedia DVDs. The complex processes involved depend upon a continuous supply of ultra-pure water. At one manufacturing company in Britain this is achieved with water purification systems designed, manufactured and installed by Wychwood Water Systems of Witney, Oxfordshire, with the help of Burkert Fluid Control Systems as key valve and instrumentation supplier. With the type of complicated processes that are involved in producing high-quality DVD masters, precise valve control is necessary.
Wychwood has supplied and installed a network of water purification units that enable its client to meet these exacting requirements. Water purification of water initially involves reverse osmosis membrane technology, counter-current three-bed deionisation and final stage of purification is with nuclear-grade mixed-bed polishing deionisers. Wood says: “With such complicated process involved, precise valve control is essential. Secondly, we needed accurate measurement and control and for this we used Burkert’s 8225 conductivity instrumentation and the 8205 pH controllers. Finally, we needed pneumatic valve islands to operate the valves – another requirement met by Burkert”.
Wychwood first turned to Burkert for solenoid valves, then for controllers, pneumatics, diaphragm valves and, of course, the solenoids. Burkert supplied a total of 56 2030 PVC diaphragm valves, operated by three 5470 pneumatic valve islands. The conductivity transmitter and pH transmitters were built into a corrosion-resistant skid-mounted assembly, cutting down on electrical and mechanical site installation.
The British project has led to a similar one with a sister company in Poland, also producing DVDs. Here, Wychwood is also providing an ultra-pure water system. Wood adds: “It is important that these purified water systems are kept cool at all times – otherwise bacteria can begin to grow. For this we use chilled water through a stainless steel 316L double skinheat exchanger. Temperature control is essential in the process of mastering DVDs. It is specified that there should be no more than a one degree change in temperature over a one hour period, which is very precise”. “To achieve that stipulation we used the Burkert stainless steel top control globe valves which provide us with the accuracy and control that we need”. The 2712 top control globe valves include the Burkert EasyLink system that connects the valve to a pt100 temperature sensor, enabling the temperature to be automatically controlled by the valve with the option of a link to a PLC.
