Proportional valve gives precise, variable flow

May 22, 2003
Proportional pneumatic valves can have hysteresis levels as high as 15%, which can wreak havoc on closed-loop control systems. Another problem with proportional valves is that they often vary from one to another in terms of maximum flow and gain. Gain is the rate of flow change to valve input current, and engineers require consistency and linearity for tight control.

 
 

To solve these problems Clippard Instrument Laboratory, Cincinnati (www.clippard.com), redesigned its EV valves, combining elements of low power and fast operation with a single moving part to provide a high cycle life. They found these characteristics could be used to make superior proportional valves.

The company adjusts the valve's magnetic field to compensate for mechanical tolerance limitations. This adjustment, combined with a low-mass element and virtually no internal friction, makes gain more consistent and linear. Maximum flow variation is held to ±10%, and hysteresis to less than 10%, thus improving performance of most closed-loop systems.

The new valves, dubbed the EVP Series, are said to provide the same reliability and long life as the company's EV valves. The new valves have standard and manifold mounting options, a variety of orifice sizes and control voltage ranges, and three electrical connector options.

Sponsored Recommendations

April 16, 2025
Clean. Compact. Less heat.
April 16, 2025
SEW-EURODRIVE Introduces DR2C motor, IE5 Ultra-Premium Efficiency Motor
March 31, 2025
Unlike passive products - made of simple carbon springs - the bionic prostheses developed by Revival Bionics are propulsive, equipped with a motor and an artificial Achilles tendon...
March 31, 2025
Electric drives are a key technology for the performance of machines, robots, and power tools. Download this guide for an introduction to high-quality mechatronic drive systems...

Voice your opinion!

To join the conversation, and become an exclusive member of Machine Design, create an account today!