Background: The master cylinder of heavy hydraulic press commonly used multi-stage pressure
relief to ensure that hydraulic oil of master cylinder flows into tank without impact.
Objective: In order to easily, safely and reliably implement this function, a multi-stage pressure relief
valve with hydraulic resistance network was designed.
Methods: This valve can steadily reduce the pressure of master cylinder through matching several hydraulic
resistances which only need one switch valve. Through expanding analysis, two-stage pressure
relief structure was generalized to N-stage structure which can control the process of pressure relief on
Results: The AMESim simulation models of multi-stage pressure relief valve were established and the
simulation results were analyzed. This valve can effectively control multi-stage pressure relief and ensure
high-pressure chamber relieves pressure without impact. The valve provides a secure and reliable
pressure relief plan for heavy hydraulic presses.
Conclusion: This paper proposed the two-stage pressure relief theory based on the hydraulic resistance
theory and extended it to the N-stage pressure relief. If system increases one module, the pressure release
rate will change one more time, which is well adaptable. Besides the multi-pressure relief valve which is
based on the pressure relief theory can realize the function of the high flow balance and adaptable pressure
relief. According to the mathematical modeling and simulations, the increasing hole diameter of the throttle
valves can make the former pressure relief rate get close to the latter. When the hole diameter is large
enough, there will be no break of the pressure relief rate. As the diameter of the damping hole increases,
the first pressure relief rate slows down, however, the whole pressure relief time is prolonged.