Selden moves to automated processing for screen wash products

London - Selden Research has installed two stand alone automated blending plants, designed by SPX Process Equipment, to optimise processing efficiency at its Buxton plant, which produces automotive windscreen wash. The systems combine alcohol, water, colourings, perfumes and surfactants in preset quantities and flowrates to service Selden’s bulk filling lines or production storage tanks as required.

Selden required for two systems offering the capabilities to produce a variety of screen washes ranging from 15% -85% alcohol (IMS) diluted with water in total production volumes up to 9000l/hr, according to Mike Scott, process systems production manager at SPX PE. Each system, he said, was supplied with a Bran + Luebbe touch screen display PLC control panel for easy recipe selection, together with specification of the flowrate and batch size requirements.

Each system is fitted with a remote progressive cavity pump in order to transfer alcohol stored externally in a bulk storage area to the main processing rig. At the rig, water is pumped using a Johnson Pumps centrifugal unit from a local break tank through a flowmeter. Depending on the specific product a concentrated pre-mix of surfactants, perfume and colouring dye is introduced to the rig from an IBC using a Bran + Luebbe ProCam metering pump and through an Endress + Hauser flowmeter with pulsation smoothing software.

“The alcohol and water is mixed in-line using a Bran + Luebbe Static Mixer,” says Mike Scott. “It passes through a mass flowmeter where we can measure the total flowrate and the density of the mix. From this we can derive total flows of both water and alcohol in order to see if we are meeting the required alcohol content.” The system uses PID control from the PLC to adjust automatically the relevant pump via speed control inverters.

The final operation is to create the finished product by bringing the premix and IMS/Water solution together through a static mixer. This process is closely monitored and uses PID control again to ensure that the final product is always within specification. Previously Selden created a batch of product manually, which was then transferred to a storage tank or directly to a machine.