Visualized research experimental platform for pre-stage structure of deflected jet servo valve

Abstract

This invention relates to the field of fluid transmission and control technology, specifically to an experimental platform for visual research on the structure of a pre-stage of a deflector jet servo valve. The platform includes an experimental bench with an internal oil tank; a motor-gear pump unit integrated within the oil tank, with its inlet connected to the tank and its outlet connected to the inlet of an energy storage device via a pipeline; and a first proportional pressure regulating valve, whose inlet is connected to the outlet pipeline of the energy storage device for regulating system pressure. This invention, by configuring a safety protection circuit consisting of the first proportional pressure regulating valve and a dual proportional control circuit consisting of a second and a third proportional flow regulating valve for both inlet and return oil paths, not only accurately sets and limits the system's maximum operating pressure but also independently and precisely controls the inlet flow and outlet back pressure of the test piece. This reproduces the real and complex working pressure and flow boundary conditions of the servo valve pre-stage, ensuring the engineering application value of the experimental results.

Description

Technical Field

[0001] This invention relates to the field of fluid transmission and control technology, specifically to an experimental platform for visual research on the pre-stage structure of a deflector jet servo valve. Background Technology

[0002] The deflector jet servo valve is a core control component in an electro-hydraulic servo system. Its pre-stage structure is intricate and complex, characterized by its tiny size and numerous shape elements. The flow field distribution and fluid flow state within the pre-stage directly determine the static and dynamic performance of the entire servo valve; therefore, a deep understanding of its internal flow mechanism is crucial. However, due to the extremely small structural scale of the prototype pre-stage, direct flow field testing presents challenges such as the difficulty in integrating measurement equipment and the significant interference that the measurement process causes with the flow field itself. This makes it difficult for traditional testing methods to effectively reveal the microstructure and dynamic evolution of its internal flow field, constituting a key obstacle in flow field mechanism research.

[0003] Currently, to address this issue, the field typically employs scaled-up models based on fluid dynamics similarity criteria for experimentation. However, providing a highly stable and precisely adjustable visual fluid supply system for this scaled-up model is a prerequisite for achieving high-precision flow field measurements. Existing conventional fluid supply systems suffer from problems such as large flow pulsations, insufficient pressure control accuracy, and slow adjustment response, failing to meet the stringent requirements of fluid power sources for high-sensitivity flow field visualization research, such as that of a deflector jet servo valve pre-stage. Summary of the Invention

[0004] The purpose of this invention is to provide an experimental platform for visual research on the pre-stage structure of a biased jet servo valve, in order to solve the problems mentioned in the background art.

[0005] To achieve the above objectives, the present invention provides the following technical solution: An experimental platform for visualizing the pre-stage structure of a biased jet servo valve includes an experimental bench with an internal oil tank; a motor-gear pump unit integrated inside the oil tank, with its inlet connected to the oil tank and its outlet connected to the inlet of an energy storage device via a pipeline; a first proportional pressure regulating valve, with its inlet connected to the outlet pipeline of the energy storage device, used to regulate system pressure; a second proportional flow regulating valve, with its inlet connected to the outlet pipeline of the first proportional pressure regulating valve, used to precisely regulate system flow; a pre-stage visual structure for the biased jet servo valve, with its inlet connected to the outlet pipeline of the second proportional flow regulating valve and its outlet returning to the oil tank via a return oil pipeline; and a variable frequency drive electrically connected to the motor-gear pump unit, controlling its speed by adjusting the power supply frequency.

[0006] In a preferred embodiment of the present invention, the energy storage device is a diaphragm energy storage device, and its inlet bypass is connected to the main pipeline between the outlet of the motor gear pump group and the inlet of the first proportional pressure regulating valve, for absorbing the pressure pulsation of the liquid flow at the outlet of the motor gear pump group.

[0007] In a preferred embodiment of the present invention, a stirrer is further provided inside the oil tank, and the stirring blades of the stirrer are immersed in the fluid medium inside the oil tank to homogenize the medium temperature.

[0008] In a preferred embodiment of the present invention, a third proportional flow regulating valve is further included. The inlet of the third proportional flow regulating valve is connected to the outlet pipeline of the pre-visualization structure of the deflector jet servo valve, and its outlet is connected to the return oil pipeline flowing back to the oil tank, for adjusting the outlet back pressure of the pre-visualization structure of the deflector jet servo valve.

[0009] In a preferred embodiment of the present invention, a precision flow meter is further included, connected in series in the connecting pipeline between the outlet of the first proportional pressure regulating valve and the inlet of the second proportional flow regulating valve, for real-time and accurate measurement of the flow rate of the medium flowing through this pipeline.

[0010] In a preferred embodiment of the present invention, a first pressure sensor is further included, the pressure measuring point of which is connected to the connecting pipeline between the outlet of the second proportional flow regulating valve and the inlet of the pre-visualization structure of the deflector jet servo valve, for measuring the inlet pressure of the test piece.

[0011] In a preferred embodiment of the present invention, a second pressure sensor 11 is further included, the pressure measuring point of which is connected to the connecting pipeline between the outlet of the pre-visualization structure of the deflector jet servo valve and the inlet of the third proportional flow regulating valve, for measuring the outlet pressure of the test piece.

[0012] In a preferred embodiment of the present invention, a measurement and control system is further included. The measurement and control system includes a programmable logic controller (PLC). The PLC is electrically connected to the variable frequency drive, the first proportional pressure regulating valve, the second proportional flow regulating valve, the third proportional flow regulating valve, the precision flow meter, the first pressure sensor, and the second pressure sensor via signal lines to form a closed-loop control circuit, so as to receive sensor data in real time and adjust the speed of each control valve and pump according to preset instructions.

[0013] In a preferred embodiment of the present invention, a temperature control device is further included, which includes a heater and a cooler disposed in the oil tank. The heater and the cooler are both electrically connected to the programmable logic controller to perform constant temperature control on the medium in the oil tank.

[0014] In a preferred embodiment of the present invention, the pre-visualization structure of the deflector jet servo valve is a magnified transparent experimental model made of high-transmittance optical glass, which has a flow chamber that simulates the flow channel of the actual deflector jet servo valve pre-stage, providing an optical measurement path for the particle image velocimetry system.

[0015] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention.

[0016] Compared with existing technologies, the experimental platform for visualizing the pre-stage structure of the biased jet servo valve constructed in this invention has the following advantages: By using a variable frequency speed controller and a submersible motor gear pump unit to work together, a wide range and high precision stepless adjustment of the flow and pressure of the test system is achieved in a flexible manner from the drive source. Compared with traditional throttling speed regulation or bypass overflow speed regulation, energy loss and system heat generation are significantly reduced. By integrating a diaphragm-type energy storage device into the pump outlet pipeline, the inherent flow pulsation and pressure shock generated during the operation of the gear pump are actively and efficiently absorbed, providing a highly stable liquid supply condition with minimal fluctuations for the subsequent pre-visualization structure of the deflector jet servo valve, thereby ensuring the accuracy and reliability of flow field visualization measurements such as particle image velocimetry. By configuring a safety protection circuit consisting of a first proportional pressure regulating valve and a dual proportional control circuit consisting of a second proportional flow regulating valve and a third proportional flow regulating valve in the inlet and return oil circuits, the maximum working pressure of the system can be precisely set and limited. It can also independently and accurately control the inlet flow and outlet back pressure of the test piece, thereby reproducing the real and complex working pressure and flow boundary conditions of the servo valve pre-stage, ensuring the engineering application value of the experimental results. The system employs a PLC automatic measurement and control system that collects and provides closed-loop feedback of key parameters such as pressure and flow rate in real time. Its control response is fast and its accuracy is high. It can maintain the system's pressure and flow rate at the set values ​​required by the test for a long time, overcoming the lag and inaccuracy of manual adjustment, and greatly improving the test efficiency and data consistency. By adding a temperature control device and a stirrer for homogenizing oil temperature, active regulation and closed-loop constant temperature management of the fluid medium temperature were achieved, eliminating the flow field variable error introduced by the change of the viscosity-temperature characteristics of the medium, so that the test results can more accurately reflect the real flow physics under isothermal conditions. Attached Figure Description

[0017] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which: Figure 1A 3D view of the experimental platform for visualizing the pre-stage structure of a biased jet servo valve. Figure 2 Internal structure diagram of the experimental platform for visualizing the pre-stage structure of the deflecting jet servo valve. Figure 1 ; Figure 3 Internal structure diagram of the experimental platform for visualizing the pre-stage structure of the deflecting jet servo valve. Figure 2 ; Figure 4 This is a schematic diagram of the mechanism in the experimental platform for visualizing the pre-stage structure of the biased jet servo valve.

[0018] In the diagram: 1. Experimental stand; 2. Oil tank; 3. Energy storage device; 4. Motor gear pump assembly; 5. Stirrer; 6. First proportional pressure regulating valve; 7. Precision flow meter; 8. Second proportional flow regulating valve; 9. First pressure sensor; 10. Deflecting jet servo valve front visualization structure; 11. Second pressure sensor; 12. Third proportional flow regulating valve. Detailed Implementation

[0019] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0020] Please refer to Figure 1-4 The present invention provides a visualization research experimental platform for the pre-stage structure of a biased jet servo valve, which mainly consists of an experimental bench 1, a pump source liquid supply module, a pulsation suppression module, a pressure and flow control module, a pre-stage test module, a sensing and monitoring module, and an automatic control module.

[0021] The experimental platform 1 serves as the integrated support base for the entire system. Its lower space houses an integrated oil tank 2, used to store and supply the clean fluid medium required for the experiment, such as water or simulated oil of a specific viscosity. The core of the pump supply module is the motor-gear pump unit 4, which is integrally integrated and completely submerged in the fluid medium inside the oil tank 2. Its inlet is directly connected to the oil tank 2. This submerged integrated design not only greatly simplifies the external connection piping but also utilizes the surrounding fluid medium for efficient heat dissipation and noise reduction of the operating motor and gear pump, resulting in a compact structure.

[0022] The drive motor in the gear pump unit 4 is connected to a variable frequency drive via a power cable. This variable frequency drive can be, for example, a Siemens G120C series high-performance vector frequency converter. By changing the frequency of the sinusoidal power supply to the motor, it smoothly adjusts the actual speed of the motor in the range of 0 to 50 Hz or even higher, thereby achieving linear and stepless control of the output flow of the gear pump and realizing flexible supply from the source of energy conversion.

[0023] On the outlet main pipeline of the motor gear pump set 4, an energy storage device 3 is connected by a bypass through a three-way connector. The energy storage device 3 is a bladder-type or diaphragm-type energy storage device with a nominal volume of 2.5L. Inside, the gas chamber and liquid chamber are completely separated by an oil-resistant rubber diaphragm. The gas chamber is pre-filled with dry nitrogen at a specified pressure.

[0024] When the gear pump is working, its inherent periodic meshing will generate flow pulsation, causing pipeline pressure fluctuation. At this time, the pulsating liquid flow enters the accumulator 3, the liquid chamber is deformed by pressure, and the pulsating energy is transferred to the compressed gas in the gas chamber and absorbed and buffered by it, thereby transforming the fluctuating pressure liquid flow into a smooth flow, effectively ensuring the high stability of the liquid supply to the downstream deflector jet servo valve pre-visualization structure 10.

[0025] The pressure-stabilized fluid first enters the first proportional pressure regulating valve 6, which can be an Atos RZMO-A type proportional relief valve. The inlet of this valve is connected to the outlet main pipeline of the accumulator 3. As a safety valve, it receives 0 to 10V or 4 to 20mA analog electrical signals from the back-end measurement and control system, and can continuously and accurately set the maximum safe pressure of the system pipeline. When the actual system pressure approaches and exceeds the electronically controlled threshold, the valve core automatically opens and overflows the excess fluid back to the oil tank 2, thereby precisely clamping and protecting the entire test circuit from overpressure damage.

[0026] After the system pressure is safely limited, the fluid flows through a precision flow meter 7 connected in series in the main pipeline. The precision flow meter 7 is preferably a Coriolis mass flow meter adapted to high-precision measurement of small flow rates, such as the Emerson ELITE series CMFS015M model, which can measure and output the mass flow rate and density signal of the fluid in real time with a high accuracy of ±0.1%, and its built-in local LED display can provide intuitive readings.

[0027] The outlet of the precision flow meter 7 is connected to the inlet of the second proportional flow regulating valve 8. The second proportional flow regulating valve 8 can be an RZMO type proportional throttle valve, which precisely controls the flow rate entering the inlet of the downstream deflector jet servo valve pre-visualization structure 10. Its opening degree is adjusted by the closed loop of the measurement and control system to meet the stringent requirements of different test conditions for flow rate and Reynolds number.

[0028] The deflector jet servo valve pre-stage visualization structure 10 is the core experimental object of this platform. It is precision-machined from high-transmittance optical glass such as borosilicate or quartz. It is a transparent experimental model that scales up the actual tiny servo valve pre-stage flow channel by tens of times according to fluid mechanics similarity criteria, such as the Reynolds similarity criterion. Its interior has precisely replicated key flow chambers such as jet nozzles, deflector plates, and receiving channels, providing an unobstructed optical measurement path for flow field visualization research using particle image velocimetry technology.

[0029] After the fluid flows through the transparent test model, it exits from its outlet. In the return oil line, it first passes through the pressure measuring point of the second pressure sensor 11 for outlet pressure detection, and then enters the inlet of the third proportional flow regulating valve 12. The outlet of the third proportional flow regulating valve 12 is connected to the pipeline returning to the oil tank 2. Its function is to establish a stable and precisely adjustable return oil back pressure in the outlet pipeline of the pre-visualization structure 10 of the deflecting jet servo valve by receiving instructions from the measurement and control system, thereby completely replicating the real inlet and outlet pressure boundary conditions of the servo valve pre-stage in actual operation.

[0030] To achieve fully automated and precise control, this platform is equipped with a measurement and control system based on an NI CompactRIO (C-RIO) or Siemens S7-1200 programmable logic controller. Both the first pressure sensor 9 and the second pressure sensor 11 are high-precision pressure transmitters from the Swiss KELU PA-21Y series. The pressure measurement points are encapsulated on the inlet and outlet pipes of the test piece, respectively, and the output 4 to 20 mA pressure signal is connected to the analog input module of the programmable logic controller.

[0031] The flow signal from the precision flow meter 7, the real-time frequency and speed signals from the variable frequency drive, and the signal from the Pt100 platinum resistance thermometer installed in the oil tank 2 are also connected to the measurement and control system. The programmable logic controller has a built-in automatic control program based on the PID algorithm, which outputs precise control signals to the variable frequency drive, the first proportional pressure regulating valve 6, the second proportional flow regulating valve 8, and the third proportional flow regulating valve 12 through the analog output module, forming a closed-loop control loop for pressure, flow, and back pressure.

[0032] For example, when the actual flow rate detected by the precision flow meter 7 is lower than the target flow rate set by the user through the human-machine interface configured by LabVIEW or WinCC, the controller will automatically increase the output frequency of the variable frequency drive or increase the opening of the second proportional flow regulating valve 8 until the deviation returns to zero, thereby achieving automated control.

[0033] In addition, to eliminate the deviation of test results caused by changes in fluid properties with temperature, the system is equipped with a complete temperature control device. A set of stainless steel electric heaters and an immersion coil cooler connected to an external chiller unit are installed inside oil tank 2. When the controller's PID loop detects that the medium temperature is lower than the set temperature, such as 25°C, it automatically activates a solid-state relay to drive the electric heaters. When the temperature rises above the threshold due to prolonged circulation, the chiller unit's circulating water pump and solenoid valve are automatically activated, removing heat through the cooler until the oil temperature recovers and stabilizes within the constant temperature range required to capture accurate flow field data. Simultaneously, the agitator 5 inside oil tank 2 continuously rotates, its propeller blades forcing convection circulation of the medium within tank 2, ensuring minimal temperature gradients and good medium temperature uniformity, thereby guaranteeing the consistency of the test's thermal boundary conditions.

[0034] The working principle of this invention is: Before the test, the user sets the target values ​​for flow rate, pressure, back pressure, and temperature using the operating software on the touchscreen. The measurement and control system issues a command to start the motor gear pump group 4 to begin low-speed scavenging circulation, and simultaneously monitors the data from various sensors in the system.

[0035] After the medium flows through the energy storage device 3 and the pulsation is eliminated, the measurement and control system uses PID closed-loop control to adjust the first proportional pressure regulating valve 6 to establish the system safety pressure cap, adjust the output frequency of the variable frequency drive to finely control the total flow, adjust the second proportional flow regulating valve 8 to precisely limit the flow into the test piece, and adjust the third proportional flow regulating valve 12 to generate the required back pressure.

[0036] When all parameters reach the set steady-state value, the PIV laser and camera can be turned on to measure the flow field containing tracer particles through the transparent flow channel of the pre-visualization structure 10 of the deflector jet servo valve.

[0037] During the test, all test data were synchronously recorded and stored by the monitoring and control system at a frequency of 10Hz or higher, providing a complete dataset for subsequent analysis. After the test, the system gradually depressurized and stopped the pump unit through a program.

[0038] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. An experimental platform for visualizing the structure of the pre-stage of a biased jet servo valve, characterized in that, include: The experimental stand (1) has an oil tank (2) inside. The motor gear pump assembly (4) is integrated inside the oil tank (2), with its inlet connected to the oil tank (2) and its outlet connected to the inlet of the energy storage device (3) via a pipeline; The first proportional pressure regulating valve (6) has its inlet connected to the outlet pipeline of the energy storage device (3) and is used to regulate the system pressure; The second proportional flow regulating valve (8) has its inlet connected to the outlet pipeline of the first proportional pressure regulating valve (6) for precise regulation of system flow. The deflector jet servo valve has a front-mounted visualization structure (10), whose inlet is connected to the outlet pipeline of the second proportional flow regulating valve (8), and whose outlet flows back to the oil tank (2) through the return oil pipeline. The variable frequency speed controller is electrically connected to the motor gear pump group (4) and controls its speed by adjusting the power supply frequency.

2. The experimental platform for visualizing the structure of the pre-stage of the biased jet servo valve according to claim 1, characterized in that, The energy storage device (3) is a diaphragm energy storage device, and its inlet bypass is connected to the main pipeline between the outlet of the motor gear pump group (4) and the inlet of the first proportional pressure regulating valve (6) to absorb the pressure pulsation of the liquid flow at the outlet of the motor gear pump group (4).

3. The experimental platform for visualizing the structure of the pre-stage of the biased jet servo valve according to claim 2, characterized in that, The oil tank (2) is also equipped with a stirrer (5), the stirring blades of which are immersed in the fluid medium in the oil tank (2) to homogenize the medium temperature.

4. The experimental platform for visualizing the structure of the pre-stage of the biased jet servo valve according to claim 1, characterized in that, It also includes a third proportional flow regulating valve (12), the inlet of which is connected to the outlet pipeline of the deflector jet servo valve front visualization structure (10), and its outlet is connected to the return oil pipeline flowing back to the oil tank (2), for adjusting the outlet back pressure of the deflector jet servo valve front visualization structure (10).

5. The experimental platform for visualizing the structure of the pre-stage of the deflecting jet servo valve according to claim 4, characterized in that, It also includes a precision flow meter (7), which is connected in series in the connecting pipeline between the outlet of the first proportional pressure regulating valve (6) and the inlet of the second proportional flow regulating valve (8) for real-time and accurate measurement of the flow rate of the medium flowing through this location.

6. The experimental platform for visualizing the structure of the pre-stage of the deflecting jet servo valve according to claim 5, characterized in that, It also includes a first pressure sensor (9), whose pressure measuring point is connected to the connecting pipeline between the outlet of the second proportional flow regulating valve (8) and the inlet of the pre-visualization structure (10) of the deflector jet servo valve, for measuring the inlet pressure of the test piece.

7. The experimental platform for visualizing the structure of the pre-stage of the biased jet servo valve according to claim 6, characterized in that, It also includes a second pressure sensor (11), whose pressure measuring point is connected to the connecting pipeline between the outlet of the pre-visualization structure (10) of the deflector jet servo valve and the inlet of the third proportional flow regulating valve (12), for measuring the outlet pressure of the test piece.

8. The experimental platform for visualizing the structure of the pre-stage of the biased jet servo valve according to claim 7, characterized in that, It also includes a measurement and control system, which includes a programmable logic controller (PLC). The PLC is electrically connected to the variable frequency speed controller, the first proportional pressure regulating valve (6), the second proportional flow regulating valve (8), the third proportional flow regulating valve (12), the precision flow meter (7), the first pressure sensor (9), and the second pressure sensor (11) via signal lines to form a closed-loop control circuit, so as to receive sensor data in real time and adjust the speed of each control valve and pump according to preset instructions.

9. The experimental platform for visualizing the structure of the pre-stage of the deflecting jet servo valve according to claim 8, characterized in that, It also includes a temperature control device, which includes a heater and a cooler installed in the oil tank (2). The heater and cooler are both electrically connected to the programmable logic controller to perform constant temperature control on the medium in the oil tank (2).

10. The experimental platform for visualizing the structure of the pre-stage of the biased jet servo valve according to claim 1, characterized in that, The pre-visualization structure (10) of the deflecting jet servo valve is a magnified transparent test model made of high-transmittance optical glass. Its interior has a flow chamber that simulates the flow channel of the actual deflecting jet servo valve pre-stage, providing an optical measurement path for the particle image velocimetry system.

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