Wychwood cleans up water supplies

Water purification systems designed, manufactured and installed by Wychwood Water Systems play a key role in the production of multimedia DVDs.

It is essential that the conditions for mastering and manufacturing DVDs meet the highest standards.

The complex processes involved depend upon a continuous supply of ultra pure water that must meet strict purity of 18Mohm resistivity and less than 15 parts per billion total oxidisable carbon.

At one major 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 and that's why Wychwood turned to Burkert.

The end user concerned is a leading name in the master and manufacture of DVDs for the reproduction of multimedia.

Peter Wood, Managing Director of Wychwood Water Systems, says: "As part of the process for manufacturing the masters and then producing the DVDs, the company requires absolute theoretically pure water.

In addition, they produce effluent from the process that requires purification before being put out to waste".

Wychwood has supplied and installed a network of water purification units that enable its client to meet these exacting requirements.

Purification of water in such an application is a multiple stage process.

The initial step involves media filtration and water softening.

reverse osmosis membrane technology is used to reduce the total dissolved solids within the feed water by 99%.

Reverse osmosis removes both organic and inorganic impurities from the water.

It is also very suitable to "high tech" industries, because as a membrane technology it provides great system integrity that can be fully validated.

It is a continuous pressure-driven process for which no chemical additions are required.

The next step in the purification process is counter current three-bed deionisation with the Wychwood Ionmaster CCP product providing water purity of 0.1uS/10Mohm.

The final stage of purification is with nuclear grade mixed-bed polishing deionisers.

Each stage polishes out more of the impurities in the water - leading to absolute theoretical water purity of 0.055uS/18.2Mohm.

This and other stages of purification can be used in a wide range of applications from electronics, pharmaceuticals, cosmetics, aerospace, healthcare, to name but a few.

Wood says: "With such complicated process involved, precise valve control is essential.

We needed good, high quality valves.

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".

In previous unit designs Wychwood had used solenoids sourced from an Italian supplier but when these proved to be unreliable they turned to Burkert for quality, reliability and off the shelf supply.

From a few solenoid valves the company soon increased its relationship to an order 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 unique 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.

Both projects illustrate Burkert's capability as a single source for valves and instrumentation.

The combination of both skills and quality equipment from both companies provide the client with a durable and reliable end result.

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