Steam and boiler specialist company Spirax Sarco has released a wafer-check directional control valve (DCV) that can be used in hot and cold water systems and can be installed in ‘reverse’ to act as a vacuum breaker, preventing the siphoning of liquids back up the pipe where it can damage upstream equipment.
The DCV can be used in mining processes and in process-line sprinkler installations and in steam and condensate lines, and, if used as a vacuum breaker, it protects equipment when the steam supply is turned off and the equipment cools.
The wafer-check valves are maintenance free and prevent reverse flow in pipelines carrying most types of liquids, steam and gases. The valves are compact and designed to fit between two pipeline flanges. The valves are available in a range of body materials, including bronze and stainless steel, with seating options of stainless steel, flouropoly- mer elastomer for oils and gases or an ethylene propylene diene monomer for water applications.
Different spring options are available, including high-temperature and heavy-duty springs for boiler and gravity feed-line applications. The company also offers an option which has no spring for very low opening differential pressures.
The valves can be installed between a wide range of flange types and in any plane. Computer-aided product design and standardised production methods ensure that the valves are of the highest quality. The robust materials of construction ensure low wear rates and the flow-path design ensures reduced instances of pressure drop.
When boilers are switched off and steam pressure is lost, the head of water above a pump can cause flow through the pump, flooding the boiler. The company’s DCV 2B valve is fitted with a heavy-duty spring and installed in the line after the feed pump to prevent gravity flow.