KSB Adds Dual-Function Valve for High-Volume Pumping

The KSB Group unveiled last month an innovative butterfly valve with an integrated shutoff and pump check valve for use in high-volume pumping operations such as industrial cooling circuits, water transport, water distribution, desalination of seawater, and hydropower.

The device is part of the Frankenthal, Germany-based company's new Dualis series of valves. (The North American division, KSB Inc., is in Henrico, Va.) The valve is manufactured in pressure classes of PN 6 to PN 40, and in nominal sizes ranging from DN 500 to DN 1400.

DN sizes refer to, of course, the valves' inner diameters (ID), which are expressed in millimeters. The ID range is thus 500 to 1,400 mm, which equates to nominal sizes of 20 to 56 in.


KSB's Dualis valves are sized for high-volume water pumping operations. The dual-function butterfly/check valves are built to customer specs.

The valve is equipped with an electro-hydraulic actuator that opens and closes the butterfly to a Category A tightness level of ISO 5208/EN 12266-1. In the event of an operational failure, a weight fitted to the lever arm closes the valve at a pre-programmed speed to protect pumps, water turbines, and pipelines from backflow or damaging surge pressure.

In a telephone interview with ThomasNet News, Keith McElroy, vice president of sales at AMRI Inc., KSB Inc.'s valve, actuator, and accessories division in Houston, added details about the design and function of the Dualis valves.

McElroy says the valves are engineered to shut off and isolate pumps if an operational problem arises. Butterfly valves and check valves are usually separate components that are installed next to each other, so the advantage he cites for the KSB design is that both components, as the name Dualis implies, are part of one unit. While there are other manufacturers that also supply integrated butterfly/check valve designs, Dualis versions are among the largest in the market, according to McElroy.

The soft-seated valve has a dry body and dry shaft and a rubber-lined inner body, he says. The only areas that contact fluid media are the disc and the rubber-lined inner body. This prevents corrosion to the outer body, as well as to the shaft, bearings, and other critical components.

The device uses a counterweight on the lever arm and a hydraulic cylinder to close the butterfly valve at a preset speed. McElroy says operators will want the valves closing or being regulated at certain speeds, so they do not slam shut when problems occur, and thereby risk damage to connecting pipes.

Each valve is built according to a user's needs. Apart from ID size and pressure specifications, typical material choices include aluminum/bronze for the disc and a stainless steel or coated ductile iron body with an inner lining of hard rubber.

Dualis valves are not inventoried by the company, McElroy says. Once a buyer places an order, the valve is built. Typical lead times for delivery range from 16 to 20 weeks, he adds, and there are no order minimums.

Modules are available for use in construction of a valve. Depending on what an end-user needs, these can include such options as special control cabinets, electrical measuring equipment, sensors, and additional controls.

The actuator is described by KSB as a compact unit that contains all of the valve's electro-hydraulic components. The actuator is designed to provide ready access to these components for assembly, disassembly, and maintenance. Electrical installation of the valve system is straightforward -- it requires a standard 3-phase, 400-volt/50-Hz power supply.

KSB Group and its global divisions clearly expect that the double-function Dualis butterfly/check valve will become an important option for specialty water-pumping applications. "When customers see the product, they will recognize the value of having this valve combination," McElroy remarked.

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