Pinch Valves Provide Superior Performance and Low Total Cost of Ownership for Lime Slurry

Calcite Limestone
Calcite Limestone
Lime is a basic industrial chemical that has widespread use in many chemical processes. It is also used extensively in food and beverages production processes. Examples of chemical industry applications are the manufacture of caustic soda (sodium hydroxide), the production of acetylene, the production of the fertilizer calcium cyanamide, the purification of citric acid, the production of pool chlorine, and the making of road de-icing chemicals. Examples of lime use in the food and beverage industry are the production of sugar, the processing of milk and cream, the production of baking powder, the ripening and storage of fresh fruits and vegetables, and the production of corn tortilla's.

Lime is normally stored as a dry powder and mixed with water or additional chemicals to create a lime slurry that can be pumped through pipes and added to the production stream as needed. The management of lime slurry to process piping, valves, and instrumentation is challenging because of lime's physical and chemical properties. Lime slurry is slightly abrasive and can be quite corrosive depending upon the other chemicals involved. Lime also has a tendency to build up as scale inside pipes and valves. This scaling can severely inhibit the operation of traditional quarter-turn valves and restrict flow. Another concern is the problem of dewatering, which happens at the point where pressure is shut off. The upstream pressure in the line ahead of a flow control valve will force liquid out of the lime, leaving a very hard, dry plug behind. The plug is hard enough to prevent the opening of a ball, plug, or butterfly valve. A significant maintenance headache occurs when this happens.

Pinch valve in lime slurry service
Pinch valves in lime slurry service.
Because of their simple, elastomer wetted, cavity-free design, rubber sleeved pinch valves have proven over time to be the best long-term solution for slurries. Pinch valves provide an excellent seal with tight shut-off, and because of their robust & straight-through design, are able to open and close regardless of obstacles in the flow tube. Other benefits making pinch valves ideal for lime slurry use are low maintenance (no bearings, seals or packing), fast opening and closing, self-cleaning and high Cv.

Control Valve
Control Valve
(Red Valve)

Pinch valves are available in 1" through 96" diameters, can be operated manually or via pneumatic or electric actuators, and perform excellently as control valves.

For any abrasive and corrosive service, and particularly for lime slurry service, pinch valves provide an inexpensive flow control solution with superior performance and very low total cost of ownership.

For more information on the proper application of pinch valves contact Process Control Solutions by calling (800) 462-5769 of by visiting