Precision in Air


November 01 2012

Proportional Valves in Test Machines


Rotating, high precision proportional valves are key elements in many modern test machines as they can be used to precisely regulate air pressures and flows and can therefore be used to accurately control the movement of cylinders.

There are many types of machines used for esting, both static and dynamic systems which can be used to test materials, fabrics, traction, compression, hardness and other machines designed to perform drop tests. Almost everything that is manufactured requires some form of testing, for example, medical equipment, automotive components, cables in lifting systems and bicycle handlebars to name just a few examples.

Tetratec is an important Camozzi customer which has used Series LRP servo valves for a long time in pressure, flow and leakage testing machines. In such applications these servo valves are used to regulate pressure very quickly and with great precision.

These valves measure and regulate parameters like absolute, relative and differential pressure in a very dynamic way, both for inert air and gases. Series LRP valves can also be used in many other applications in addition to testing machines including, for example, in laboratories and production processes.

They can also be used as a reference in the calibration of less precise systems.

Series LR proportional valves are integrated electro-pneumatic systems which operate using a rotating spool driven by an electric motor that oscillates at +/- 30° in less than 5ms and a pressure sensor which precisely regulates the pressure value. This patented system guarantees maximum pressure and speed whilst also reducing cycle times and air consumption.

A miniature electric motor is used to drive the rotating spool and the angular position of the spool is controlled by an integrated electronic device which ensures a high degree of accuracy with negligible hysteresis. Series LR servo valves can operate at frequencies greater than 70Hz with response times that vary from 1 to 5ms (regulation from 0 to 100%).

Linearity and repeatability can reach values of less than 1%. Regulation precision is within 1m bar or less. Autonomous plug and play components are available which integrate the command actuator, regulation controller and pressure sensor all within the same body.