Chemical digesters are used in paper mills to chemically break down wood in order to separate wood fibers from the lignin glue that holds them together. Using heat and special chemicals called liquor, wood is broken down into dissolved organic materials and a collection of alkali compounds. Both components are also referred to as liquors, and retain a high amount of chemicals. Both are also difficult to handle with traditional metal ball, plug and gate valves due to their high solids content, thick consistency and the chemicals involved.
To reduce wear and ensure reliability, the valves used to control these liquors must be compatible with the chemicals in question. They must also be able to control thick slurries, seal on entrapped solids and not be subject to abrasive wear.
Control Pinch Valves from Red Valve are used on many different liquor applications because they offer several advantages over traditional metal valves. At the heart of a pinch valve is a full face-to-face elastomer sleeve that is the only wetted part of the valve. High-quality synthetic elastomers ensure chemical compatibility and abrasion resistance.
The rugged flexibility of the sleeve allows it to seal on entrapped debris for a drop-tight seal. The sleeve also has a full-port, allowing maximum flow with no obstructions. When throttled, the sleeve maintains a streamlined flow path, with no obstructions or changes in the direction of flow.