Slurry Handling and Piping Systems
A slurry can be loosely defined as any material that is primarily a liquid, but contains more than 10% solids. A slurry can be anything from pure water that contains a small amount of sand, to materials like lime mud that are very thick and viscous. Valves designed long ago for use on domestic water systems cannot always handle the rigorous demands of slurries.
As an example, lime slurry is often used in pH control. When a valve is shut, the upstream pressure in the line tends to de-water the lime, leaving a dry plug at the point of closure. When the valve is opened again, this plug will block the flow. Quarter-turn valves often compound the problem by packing the lime even tighter when they are operated. Lime will also quickly scale and build up inside the valve, especially in any crevices or dead spaces that exist. The solids content of a slurry also makes it difficult to achieve a tight seal when closing. The seating area of metal valves can become blocked by or filled with solids, preventing a bubble-tight shut off.
Red Valve Control Pinch Valves are designed to handle even the most difficult slurries. The elastomer walls of our pinch valve sleeves resist abrasion and seal tight around entrapped solids. The flexing action of the sleeve breaks up dewatered material and prevents buildup.