Mechanical and System Simulation Modeling and Analysis of Surge Relief Valve

Surge pressure relief valve is widely used in oil transportation. When water hammer occurs in the pipeline, the valve shall be opened in time to release the high pressure so as to ensure the safety of the oil pipeline. This paper discusses the structure and principle of the surge relief valve. Combined with the working process, the stress and working state of the main valve and the pilot valve are analyzed. The mechanical model of the pilot valve is established. This paper focuses on the analysis of the parameters affecting the closing process of the main valve. The relevant laws of the structure and performance parameters of the pilot valve to the main valve closing are obtained. The model of relief valve is modeled and simulated in detail by the AMESim software. The dynamic characteristics of the surge relief valve are analyzed and the correctness of the main parameters and rules that affect the main valve closing is verified by using the model. According to the analysis and simulation results, the friction force of the pilot valve can only affect whether the two valves can close normally. The closing time of the main valve is inversely proportional to the diameter of the inlet pressure orifice. In the normal operating range, the closing time of main valve gradually increases with the diameter of outlet pressure pipes, but does not change with the length of outlet pressure pipes.

Simulation of Dynamic Characteristics of Pneumatic Control Valve With Smart Valve Positioner

In this research, in order to predict the dynamic characteristics of a regulating valve, a mathematical model is proposed for a pneumatic control valve using a smart valve positioner (AVP300), and the dynamic characteristics of the control valve were simulated. We modeled the components of the control valve (i.e., nozzle flapper, pilot valve, Auto/Manual (A/M) screw, bleed orifice, pneumatic actuator, gland packing, and pressure reducing valve), and simulated the dynamic characteristics using SimulationX, a one-dimensional analysis software. For the nozzle flapper, we proposed a model that considers the influence of fluid force due to pressure change as well as the influence of the change in effective area by measuring the displacement, pressure, and flow rate of the nozzle flapper. The diaphragm chamber, which operates the pilot valve of the positioner, was made of transparent acrylic. The displacement of the pilot valve was measured by a laser displacement sensor, and its movement against pressure change was clarified. The sonic speed conductance and critical pressure ratio of the A/M screw and bleed orifice were determined experimentally and reflected in the model. In the pneumatic actuator, the effective cross-section of the diaphragm was obtained from the change in pressure and displacement. The change in volume was calculated from the experiment using a fixed chamber. The friction force of gland packing was modeled using static and dynamic friction forces. The experiment on the dynamic characteristics of valve displacement was performed with the input signal of the valve displacement set from 20% to 80%. A comparison of the experimental results of the valve displacement and simulation results showed good agreement. The simulation in this study is considered effective in predicting the dynamic characteristics of the control valve.

Using a Multi - function Pressure Valve in Volumetric Hydraulics Drives

The paper deals with using hydraulic equipment for pressure and flow control in volumetric hydraulic drives to control a throttle movement speed of the output link of an executive hydraulic motor. Depending on the type of problem to be solved, hydraulic equipment is divided into the pressure and flow control, and the shutoff and regulating elements used in equipment are divided into those of valve and spool type. The main paper objective is to analyse designs and feasibilities for using a multi-functional pressure valve to solve real-life problems of control in a volumetric hydraulic drive. The paper presents a multi-function indirect pressure valve design of DZ standard size (Rezroth Bosch Group) and its detailed principle of operation. In the multifunctional pressure valve design there are threaded plugs, the combination of which allows us to control the pilot valve, using the pressure in the hydraulic system (internal control) or the pilot valve control from an external pressure source. Pilot drainage to the valve outlet port (internal drainage) or drainage directly to the tank is possible. It is shown that the term “Load Sensing System” that is used in Western equipment to mean “control based on load magnitude” can be correctly used to describe designs for using a multifunctional valve.Issues on setting up internal functional communications of the valve to select feed modes of a pilot valve and its drainage have been fully considered. By examples of using a multifunctional pressure valve, the valve operation capabilities are shown, namely as an overflow valve, a sequence one, its operation in the balancing scheme of the gravity load and as part of a hydraulic drive with alternating load. The use of multi-function pressure valve in presses allows us to increase the pressing force through using the weight of the punch. The article belongs to the category of systems engineering, and the represented options of the using valve can be applied when designing the volumetric hydraulic drives with throttle control of the movement speed of the output link in hydraulic drives.

Parametric Study on Fluid Dynamics of Pilot-Control Angle Globe Valve

Globe valve is widely used in numerous industries, and its driving energy consumption accounts for high percentages of the whole piping system. In order to figure out novel globe valves with low energy consumption, the pilot control globe valve (PCGV) is proposed, which is made up of a main valve and a pilot valve. By the pressure difference of fluid itself, the opened/closed status of the main valve can be controlled by the pilot valve, which can save driving energy and shorten the response time. In order to fit PCGV in an angle displaced piping system, the pilot control angle globe valve (PCAGV) is developed. In this paper, with validated numerical methods, both steady and transient simulations focusing on the valve core diameter, the single/multi orifices, orifice diameters and their arrangements located on the valve core bottom are presented. The results show that the pressure difference increases with the increase of the valve core diameter and the decrease of the orifice diameter, and large orifice diameters (d > 12 mm) should be avoided in case the valve cannot be opened. As for the multi orifices, it can be treated as a single orifice which having similar cross-sectional area. Meanwhile, the opening time of the main valve also increases with the increase of the valve core diameter correspondingly. Besides, a fitting formula of pressure difference calculation depending on the inlet velocity and the valve core diameter is obtained, which is a power–law relationship.