Analysis of Dynamic Characteristics of Pressure-Regulating and Pressure-Limiting Combined Relief Valve

Tao He,Chuanli Wang,Tian Xie,Rui Shi,Alessandro Mauro

doi:10.1155/2021/3486143

Tao He, Chuanli Wang + Show 3 more

Open Access

https://doi.org/10.1155/2021/3486143

Copy DOI

Abstract

Aiming at the problem of the lack of a cooperation mechanism of combined relief valves, this paper proposes a new pressure-regulating and pressure-limiting combined relief valve. Combined with the ordinary relief valve dynamic characteristic analysis method, the dynamic model of the combined relief valve under normal working conditions was established, and its dynamic characteristics were simulated using Simulink. The results showed that the multi-pressure stabilization design of the combined relief valve improves its usability and stability. Under the same structural parameters, the overshoot of the combined relief valve was 5.7%, and the response time was 12 ms, which is better than the ordinary relief valve. Besides, it effectively improves the instability problems, such as the vibration and the large pressure fluctuation of the ordinary relief valve under high pressure and large flow conditions. When the sum of the effective force area on the upper side of the flange of the pressure-regulating valve core and the area of the tail vertebra is equal to the effective force area of the lower side of the flange of the pressure-regulating valve core, the dynamic performance of the relief valve is optimal. For example, if the effective force area under the flange is 1.8 cm2, then the inlet pressure overshoot is 2.8%, and the response time is 10 ms. An appropriate volume of the sensitive cavity, the quality of the valve core, and the fluid resistance of the pressure relief valve are factors that can effectively improve the dynamic performance of the pressure-regulating and pressure-limiting combined relief valve.

Highlights

Relief valves are key components of pressure regulation mechanisms in hydraulic systems, and their performance directly determines the pressure stability and the safety of hydraulic systems [1, 2]
According to the block diagram of the pressure-regulating and pressure-limiting relief valve established in Figure 3, Simulink software was used to establish its model. e variable step-size Runge–Kutta algorithm was used for numerical simulation to investigate different factors. e impact on the dynamic performance of the relief valve was recorded
Combining the previous research methods on the dynamic characteristics of ordinary relief valves, this paper establishes a mathematical model of the combined relief valve under normal working conditions and uses Simulink software to simulate its pressure-regulating dynamic characteristics. e conclusions were drawn as follows

Summary

Introduction

Relief valves are key components of pressure regulation mechanisms in hydraulic systems, and their performance directly determines the pressure stability and the safety of hydraulic systems [1, 2]. When the inlet pressure increases to the specified pressure of the pressure-limiting valve, the concave-convex structure of the valve core makes the pressure-limiting valve sensitive cavity communicate with the pressure-regulating valve spring cavity, the pressure-limiting and pressureregulating valves are synchronously opened, and the double valves are relieved of the pressure, which is beneficial to the release of high pressure and large flow, ensuring the system safety It can be seen from the above working principle that in the pressure-regulating and pressure-limiting combined relief valve designed in this paper, the spring of the pressure-regulating valve and the spring of the pressure-limiting valve are soft, and the spring of the pilot valve is harder, effectively avoiding the resonance phenomenon caused by the direct use of the pressurelimiting valve and the pressure-regulating valve due to the close control pressure. X sin 2 φ Bw1 CdπD1􏼠1 − 2D1 􏼡sin 2 φp, where p1 is the inlet pressure of the pressure-regulating valve; A1 is the effective force-bearing area under the flange of the pressure-regulating valve core; p2 is the sensitive cavity pressure of the pressure-regulating valve; A2 is the effective force-bearing area on the upper side of the pressureregulating valve core flange; p3 is the sensitive cavity pressure of the pressure-limiting valve; A3 is the effective forcebearing area of pressure-regulating valve tail vertebra; m1 is the quality of the pressure-regulating valve core; x is the valve opening of the pressure-regulating valve core; Bs1 is the pressure-regulating valve transient hydrodynamic damping; Bx is the viscous damping coefficient of the pressureregulating valve; Kx is the pressure-regulating valve return spring stiffness; x0 is the precompression of the pressureregulating valve spring; Bw1 is the pressure-regulating valve core steady-state hydrodynamic stiffness; Cd is the flow coefficient of the relief valve; D1 is the diameter of the pressure-regulating valve; φ is the pressure-regulating valve core half cone angle; ρ is the density of the fluid; and L is the pressure-regulating valve damping length

Pressure and Flow Equation of the Pressure-Regulating

Flow Equation Flowing through a Fixed Liquid

Results and Analysis

Conclusion