Using automation to improve process water quality

Process water often has to be modified to meet the required quality standards, either as part of a manufacturing process or to prevent corrosion, microbiological build-up or scale formation. Monitoring a combination of pH, chlorine, reduction potential (ORP), temperature and conductivity is the first step in achieving the optimum process conditions. Combined with precision flow measurement and control circuits, the quality of process water can be achieved and documented.

From cooling towers to craft breweries, process water has a wide variety of uses and each application has different demands. Water quality is often controlled using a blending process that combines two sources of water of known quality to produce the required process quality. This can be achieved either by ratio control or quality control procedures.

Preventing corrosion and the deposition in cooling towers for example can be achieved through the careful blending of treated and raw water to create the right balance for make-up water used to maintain system levels. Water blending also has a significant effect on consumables such as beer, where the taste is affected by the water composition going into the fermentation process, so monitoring and maintaining a high-quality source of process water is essential.

Fixed ratio control requires the quality of both the raw water and the pure water to remain consistent. To achieve this, flowmeters are used on both lines and a control valve is used to deliver the correct ratio for the blended water. The alternative is to use a water quality monitor that is set up to measure a parameter, such as conductivity. This monitor is linked to the water supply valves via a control loop that regulates the blending proportionally and can therefore compensate for variations in supply quality.

Designing and creating these control systems requires considerable expertise to ensure that they perform reliably and are properly integrated with the surrounding control infrastructure. Process control experts at Brkert have created an extensive range of compatible flow control and quality measurement products that can be combined to deliver an optimised quality control system that can be scaled to suit any process.

Systems can be designed around pneumatic or electrical valve actuation and in-line sensors, using either a stand-alone process controller such as those offered by Brkert or using PLC control that is incorporated within the wider process environment. Smaller systems can be pre-assembled from standard products and bench-tested prior to installation, while larger, more complex designs can be individually designed and kitted to ensure smooth integration.

Go to www.burkert.co.uk for more information.