Due to the natural water hardness in Hertfordshire, Newsprinters had installed an RO system to purify the local water supply before using it in the dampening process on the printing presses. This delivered a purified and very soft water resource. However, to meet the requirements of the printing press manufacturer, a chemical had to be added to bring the water hardness up to a specified level, 9 or 10 on the German water hardness scale.
Paul Wesley, Group Technical Manager, at Newsprinters, explains:“We had identified the process of re-hardening the water as having the potential for improvement, provided we could find a way to blend the two water sources accurately. Our facilities management (FM) team suggested Bürkert as a possible partner in this project; as a well-respected supplier of high-quality, reliable process control equipment, it was an easy decision.”
There are essentially two ways in which to achieve a water blending solution – using flow meters and a flow control device to deliver a set mix ratio or by installing a conductivity sensor that is linked to a flow control valve on the raw water line. Bürkert’s engineers suggested the latter option as the most cost-effective and accurate system.
The FM personnel installed the additional pipework, flow control valve and the conductivity sensor, with assistance from Bürkert in commissioning the new system. By eliminating the cost of around 1,000 litres of re-hardening chemical each week as well as the environmental benefits of not having to transport the chemical to the plant, Newsprinters has achieved significant savings through this project.
Emmet O’Sullivan, Account Manager for Bürkert, comments: “As soon as we looked at the application, it was clear the most effective solution would involve a conductivity sensor and a closed-loop feedback to the control valve. This would ensure continuous accuracy and take account of any changes in the quality of the raw water source. We commissioned the control valve and assisted with the installation to ensure the seamless introduction of this solution.”
Once the water blending installation was complete, the hardness of the water was carefully monitored and found to be both accurate and reliable. The printing works is arranged in such a way that there are two separate water supply systems, so while the water blending solution was being trialled on one, the second line remained with the original re-hardening chemical.
Paul Wesley concludes: “After six months of successful trials, we requested a second blending unit from Bürkert, and both have now been in use for several months. It was soon apparent that the new system was able to accurately maintain the water hardness at exactly the point we needed. As a result, we have made a significant saving in terms of our chemical requirements and reduced our CO2 footprint at the same time.”
Digital electro-pneumatic process controller for integrated mounting on process control valves
- Compact and robust stainless steel design
- Easy start-up via Tune function for position and process controller
- Contact-free position sensor
- Integrated pilot air duct with spring chamber aeration
- PROFIBUS DP-V1, EtherNet/IP, PROFINET, Modbus TCP or büS (Bürkert System Bus)
Pneumatically operated 2 way Globe Control Valve
- Excellent control characteristics
- High cycle life and maintenance-free operation
- Flow optimised body in stainless steel
- Several Kvs value per port size due to removable valve seats
- Control units can be mounted directly without external tubing