Page 7 of catalogue Needle valves of Erhard GmbH & Co. KG

The perfect solution, even for special requirements
ERHARD RKV Needle valves are suitable for classic uses such as the bottom outlet control and safety devices in turbines and Pipes as well as for numerous other specially applications: A Shut-off device in pipes with high operating pressure and high flow velocities A Pump start-up valve A Return flow prevention for Pumps with drop weight A Piston type check valve A Safety overflow valve for removing impermissible pressure increases in the Pipe system (free of auxiliary power) A Bypass outlet surge protection in pipelines A Pilot operated pressure-reducing valve (free of auxiliary power) A Pipe burst protection A Turbine bypass A Turbine control A Filling valve for high pressures and pipe discharging in the open air or for large pipelines A Flushing/purging valve A Pump test rig A Air flow rate control in aeration Tanks A Industrial applications A Pressure control device in natural gas pipes

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ERHARD is in demand worldwide as a competent partner for large and small projects. The company repeatedly verifies its expertise by achieving success in even the most demanding and sophisticated projects. Here are a few examples: Water power is one of the cleanest sources of energy on the earth. Modern technologies make this resource more and more economically viable. An ERHARD needle valve with ingenious Control engineering [1] was installed in the secondary turbine outlet during the modernisation of a River Danube power station. The valve operates autonomously via its own medium control and if the turbines are shut down, pressure surges and therefore risk to the plant are reliably avoided. In storage operation of large drinking water supply Plants, geodetic energy is often available virtually free of charge. Reliable Valves suitable for use with drinking water are necessary in the parts of the plant in which energy recovery is possible. An example of the use of ERHARD valves for these application cases is a needle valve DN 600 PN 16 with weight-loaded Hydraulic

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actuator and magnetic clutch [2]. Up to 1,200 l/s have to be safely controlled upstream of the turbine and must be stopped reliably and without surges if the turbine is shut down. In this application case, ERHARD proves to be a competent partner for the project planning and design of valves. In a drinking water project in the United Arab Emirates, 380,000 m³ extremely precious drinking water are distributed into desert regions daily. The net includes a 180 km pipeline, in which more than 500 ERHARD valves DN 200 to DN 1600 are used, including 32 ERHARD needle valves (DN 700, pump bypass 56 bar, pressure release) [3] with all kinds of different tasks. An especially adapted version in seawater desalination plants ensures continuous, fault-free operation. A task which involves very high standards for the design of the valve. Apart from their use in the drinking water sector, needle valves are also used in the wastewater sector, e.g. for aeration control in a wastewater treatment plant [4].

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