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

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 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
(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 https://flowcontrol.processcontrolsolutions.com.

Pinch Control Valve for Wash Water Discharge in Treatment Plant

In wastewater treatment plants a pressure control valve is often needed on a standby pump to control discharge of wash water from the wash water pumping station.

Wash water discharge diagram using pinch control valve (Red Valve) 

Red Valve Series 5400

The main pump and the standby pump are rated to provide maximum flow at a constant pressure. A pressure sensor with integral transmitter is required to continually monitor system pressure. Under normal operating conditions, the pressure control valve is normally closed. After the surface wash shuts down, pressure from the discharge pump changes. The sensed line pressure is transmitted to a controller which sends a signal to the positioner on the control valve.

As the line pressure increases, a Red Valve Series 5400 control pinch valve opens. As the flow demand increases, line pressure decreases, and the valve closes. This system constantly maintains the pressure needed to operate the system. From the pressure control valve, the system discharges to atmospheric pressure over a clear well.

Due to the potentially high pressure drop conditions, the pressure control valve needs to be able to withstand the effects of possible cavitation. Red Valve Series 5400 control pinch valves, with their one-piece elastomer cone sleeve construction, are ideally suited for this application. The flow characteristics and pressure drop capabilities of the cone sleeve controls the flow and handles the pressure drop in the system. To assure cavitation does not occur, a TFO variable orifice to stage the system pressure drop by creating back pressure on the control valve. This setup fulfills the need of the treatment plant, and is a proven cost-effective, maintenance-free solution.

Reprinted with permission from Red Valve.

Valve Selection Guide for Wastewater Treatment

Wastewater Treatment Facility

Over the past 30 years, the process of wastewater treatment has seen dramatic changes as world populations continue to increase and concern over the environment grows. Ever more stringent regulations for wastewater quality have been met with high-tech engineering. Red Valve Company has worked closely with the designers and operators of wastewater treatment plants across the globe to provide innovative solutions for the most difficult challenges faced in a treatment plant.

Unlike most valve companies who view water and wastewater as one and the same, Red Valve provides products specifically engineered for the rigors of use on slurries such as sewage, sludge and grit. Red Valve provides a Total System Solution for Wastewater Treatment that encompasses every step of the treatment process, from collection to final discharge. Their commitment is to provide dependable, cost effective products that offer the best possible solution for their particular application. See the brochure below for specific water treatment facility applications where these products provide a proven, superior engineered solution.

Contact Process Control Solutions with your valve and actuation requirements by calling (800) 462-5769 or by visiting https://flowcontrol.processcontrolsolutions.com.

Red Valve Solutions Guide for Wastewater Treatment Facilities from Process Control Solutions, LLC