Valve for Slurry of OPC, PFA Lime & Anhydrite

A construction company producing aerated blocks for various building requirements across commercial and residential developments are using valves from AKO UK within their manufacturing process.

Aerated concrete blocks are amongst the most environmentally friendly building products available. Every part of the process is designed to minimise waste and maximise energy efficiency, from selection of raw materials, to the energy-saving manufacturing technology.

How the Valve for Slurry Assists in this Application

The aerated block manufacturing company use the valves from AKO UK to weigh off a slurry for the production of the aerated blocks, to fill weigh a hopper. The slurry is made up of ordinary portland cement (OPC), pulverised fuel ash (PFA), lime and anhydrite. At a temperature of around 30-35 degrees C, certain amounts of the cement slurry is conveyed through the pinch valve which accurately controls the flow.

Pinch Valve used within this application – VF100.03X.31.30LA

VF model, air operated, aluminium body, aluminium flanges PN10/16 with mild steel bushing contact parts, natural rubber sleeve.

The pipe work is always open ended, and the valve is installed onto horizontal pipe work. The Pinch Valve is normally open, and performs 350 cycles per week. 4 bar air pressure is available to close off the valve.

Valve for Slurry: New and Improved Design

The Pinch Valve installed on this hopper is an old Paladon style valve. Paladon Valves was a valve distribution company that was bought out by AKO GmbH (German head office) in 2000, and renamed AKO UK Ltd.

The main difference between Paladon valves and AKO valves is the body shape. Paladon valves were very round and bulbous shaped, whereas the AKO pinch valve has an elliptical shaped body which uses less air consumption and ensures that the sleeve closes in the same way every time.

AKO Pinch Valves are also a lot more light weight because they no longer have heavy cast iron flanges. Instead they now come in aluminium with a choice of bushing material if required, such as mild steel or stainless steel.

The rubber sleeves inside the AKO Pinch Valves are also improved with extra walls, and are therefore longer lasting. The AKO valves also have a true and full bore, whereas with the older Paladon valves, sometimes the sleeve would reduce the bore.

Valve for Slurry: Timescale of Replacing Spare Parts

It is great that this old valve is still going strong, performing to a high standard after so many years in service. AKO UK provide the replacement internal rubber sleeves for the valve, which have not needed to be replaced very often over the years in this case. It is difficult to pinpoint an exact lifetime of the sleeves in this application because it depends if there is something sharp in the slurry. However, one of the pinch valves on this site was resealed in 2015 and is still in use with the same sleeve installed – 7 years later! The site engineer informed us that the valve most likely sat in stores for a number of years before it was installed too.

The Pinch Valve is operated via a solenoid valve. The aeration block manufacturing company started using pinch valves within this application due to a recommendation from the design engineer, who reports that “The valve works well with very little maintenance.”