Potable Water System Products

February 2005 » New & Noteworthy

Solenoid actuation valves

Parker Fluid Control Division offers the Valve Actuation Series of solenoid valves for applications in which solenoid valves must actuate the movement of larger process valves to control the flow of liquids or gases. The valves are available in pipe- and Namurmounted models, have a pressure range of 30 to 150 psi, and an operating temperature range of minus 40°F to 167°F. A conversion plate enables users to alter the valve's function onsite from four-way to three-way operation. A captured pilot exhaust eliminates external contamination and the need for additional piping connections. The valves are constructed of hard-coat anodized aluminum, brass, and stainless steel.

Parker Fluid Control Divison

Torque-limiting actuator

The Flowserve Limitorque SMB, multi-turn electric actuator can produce torque ranging from 15 foot-pounds (ft-lb) to 60,000 ft-lb, and can handle stem thrusts as great as 500,000 pounds in water treatment and distribution applications. An automatic torque-limiting feature, however, deenergizes the motor to prevent damage to the valve if an obstruction is encountered. A double-reduction gear set (helical and worm), available in several combinations, eliminates speed-vs.-torque sizing trade offs, according to the manufacturer. The SMB also offers single- or double-compensating spring assemblies that can be added to the gear housing for high-temperature or high-speed applications.

Flowserve Corp.

Critical pipe analysis

Wallingford Software plans to launch later this year a Critical Link Analysis tool as part of the next release of its InfoWorks hydraulic modeling and data management software for the water industry. InfoWorks can estimate the criticality of a single pipe; the new tool will automate this modeling process for every pipe in an input list. The program will calculate the risk associated with each pipe, with risk defined as the probability of failure -- inferred from data on the pipe condition and type -- multiplied by the impact of failure. This model can be used to identify critical links in a water distribution system, design a response strategy, test alternative solutions, and ensure an alternative water supply. Reports will show local versus remote effects of pipe failure, residual pressure, duration, remote residual pressure, remote duration, and maximum pressure.

Wallingford Software Ltd.

 

Flexible reservoir covers

DuPont Dow Elastomers' Hypalon©, a chlorosulfonated polyethylene synthetic rubber, is used in flexible, geomembrane liners and covers that meet ANSI/NSF Standard 61 for potable water storage facilities.

Hypalon covers are produced by laminating the polymer to both sides of a woven polyester scrim. The covers reduce evaporation losses, retard chlorine depletion, prevent algae growth, and keep out airborne pollutants and other contaminants.

Hypalon has a low thermal expansion coefficient and is resistant to damage from ultraviolet radiation. To reduce the number of field seams and to decrease installation costs, covers and liners are factory fabricated into custom-designed, large panels, and folded or rolled on a core for shipment. They are available in several colors to blend into the surrounding environment.

DuPont Dow Elastomers

Spray-on tank linings

Sherwin-Williams' AR 520 PW EnviroLastic© Polyurea coating, part of the company's ControlTech—„¢ coatings line, meets ANSI/NSF Standard 61 for potable water use, with a minimum tank size of 50 gallons. It is an alternative to fiberglass liners and other mat-reinforced systems for lining most concrete and steel water tanks, as well as largediameter pipes, manholes, clear wells, and process tanks for potable water. The no-VOC, no-odor coating can be applied at temperatures as low as minus 20°F and in high humidity, but must be applied by Sherwin-Williams-certified contractors. The coating dries tackfree in as few as 45 seconds.

Sherwin-Williams Co.

Low-temperature epoxy coating

PPG High Performance Coatings offers Aquapon© LT, an NSF 61-certified, low-temperature epoxy coating for concrete and steel potable water tanks of 1,000 gallons or greater capacity. The coating cures at temperatures as low as 32°F and exhibits a dry heat tolerance of 300°F. When an appropriate film thickness is achieved -- 4.0 to 7.0 mils (dry) -- Aquapon LT does not require a top coat for corrosion protection and is ideal for harsh environments, according to the company. It is a low-VOC product and is available in two, ready-mixed colors -- industrial gray and industrial white. At normal temperatures, Aquapon LT dries to the touch and can be recoated in four hours; handled in six hours.

PPG High Performance Coatings


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