The Muffler Performance Effect on Pressure Reducing Valve Dynamics

The gas pressure control units are widely used for various applications. Very often such units operate at large flow rates and pressure drops, thus becoming a powerful noise sources. The problem of noise reduction and protection is a formidable challenge for the design and operation of such units. One of the ways for noise reduction is a muffler installation. However, the in-line installation of such devices may cause malfunction of the pressure reducing valve. Any variation in the output line impedance may provoke instability and self-exited oscillation of the regulator. In this paper the muffler's effect on pressure reducing valve dynamics is studied. The subject of research is a muffler installed at the pressure reducing valve outlet. The mathematical model of this system is implemented in the Simulink software to analyze the muffler impact on pressure reducing valve static and dynamic characteristics and to estimate the system noise level. The dependences between the system and muffler parameters are obtained as a result of simulation. The experimental research at the pneumatic bench is implemented for mathematical model verification. The muffler effect on transient process quality is analyzed. Stability domains are calculated and the muffler influence on system stability margin is evaluated. The theoretical results demonstrate acceptable correlation with experimental data.