Characteristics of an electro-pneumatic power modulator
Transmissions of pneumatic power - Electropneumatic power modulators

An electro-pneumatic power modulator controls gas energy transfer by driving variable-area orifices.

For compressible fluids, the mass flow through each passage section is a function of the pressures upstream and downstream of the section in question. ISO 6358-1989 proposes a mathematical approximation of the laws of flow through a fixed restriction using two parameters:

• the sonic conductance C, expressed in m³ · s ^–1· Pa^–1, the image of the effective cross-sectional area of the component determined in the sonic regime;

• the critical pressure ratio b, delimiting sonic and subsonic flow regimes.

According to the following expressions :

In the sonic regime,...