Spool Valve Research Articles

Procena položaja bez senzora i identifikacija vremena prelaza za kalem elektromagnetnog ventila velike brzine za uključivanje/ isključivanje

In this paper, a sensorless method of detecting the spool position of a high-speed on/off solenoid valve is presented. The method depends on analyzing the time-current curve of the solenoid coil passing current and measuring the maximum stroke of the valve spool, such that the dynamic behavior of the valve is estimated and the spool displacement curve is plotted. A mathematical model of the solenoid valve is developed and the effect of the hydraulic force on the valve spool is studied. Experimental results show that the proposed method error is less than 7% when compared to valve spool displacement measured by the commonly used linear variable displacement transducer.

Generation Mechanism of Flow Force Acting on Spool Valve

Generation Mechanism of Flow Force Acting on Spool Valve

Instability Measurement of Cavitation Conditions in a Spool Valve Through the Definition of a Cavitation Instability Index

Instability Measurement of Cavitation Conditions in a Spool Valve Through the Definition of a Cavitation Instability Index

Discrete-time Adaptive Control of Pneumatic Actuators for 6-DoF Stewart Platform

This paper deals with computer-controlled pneumatic actuators for the Gough-Stewart platform with 6 degrees of freedom. An important feature considered in the paper pneumatic actuator is the use of a group of valves rather than a spool valve to control the pressure in the chambers, which leads to a significant quantization in terms of the level of the control action. In addition, there is a sampling in time in the control loop. The present work is aimed at ensuring the robustness of the pneumatic actuators for the Stewart platforms concerning their parameters and the effect of changing the load on the drive caused by the interdependence of the drives due to the movement of the platform. Two discrete-time (parametric, and signal-parametric) adaptive control algorithms, based on the concept of an implicit reference model with anti-windup correction are proposed. The simulation results are presented, demonstrating the efficiency of the signal-parametric algorithm.

Flow Characteristic of a Cavitating Jet Issuing from a Small Rectangular Orifice

This study focused on the nature of a cavitating jet issuing from a small rectangular orifice the same size as a control port in a water hydraulic spool valve. The aspect ratio of the jet exit was varied to investigate the cavitation jet behavior. The flow characteristics for each aspect ratio were measured, and the jet behavior was observed with a high-speed camera. The flow characteristics of cavitating jets are changed with the aspect ratio and cavitation number. The larger aspect ratio orifice shows a higher flow rate and larger cavitation number of inception. Visualization of a cavitating jet shows that the behavior of cavitation bubbles depends on the aspect ratio. The cavitating jet region is maintained to the same dimensionless position for all aspect ratios. In addition, the distribution and time history of luminance of the visualized images for each aspect ratio shows that the cavitation generates stably in the jet shear layer.

Ušteda energije i poboljšanje performansi elektromagnetnog ventila velike brzine za uključivanje/isključivanje

High-speed on/off solenoid valves (HSVs) are digital vales commonly used in hydraulic power systems. These valves are usually used in pressure and flow control which requires high dynamic and energy performance to improve the control accuracy. This paper aims to propose a new control method used to improve the dynamic and energy performance of HSVs. The proposed method is based on the pulse width modulation (PWM) technique implemented by LabVIEW software and NI myRIO. Based on that, NI myRIO has a real-time module; no feedback is needed. A mathematical model of the HSV is introduced, describing each subsystem of the vale and its interactions with each other. The proposed method is validated under different operating conditions. The results show that applying the proposed control method on the HSV will reduce the valve spool closing time by 72% and reduce energy consumption by 94% compared to the traditional on/off control method.

Position Control Algorithm of Fuzzy Adaptive PID of Hydraulic Interconnected Suspension Under Load Impact Disturbance

Position control accuracy of hydraulic interconnected suspension (HIS) for agricultural vehicle is unsatisfied under load impact conditions. In order to address this problem, advanced control methods were studied in this paper. The technical scheme of HIS was developed firstly. The transfer function from proportional valve spool displacement to hydraulic cylinder piston displacement was derived and then the parameters of the transfer function were also identified. The PID, sliding mode control (SMC) and fuzzy adaptive PID (FAPID) control algorithms were designed. The co-simulation of AMESim and SIMULINK was adopted to compare and analyze the control characteristics of the three algorithms. An experimental platform was also built to verify the improvement effect. The research conclusions show that when the HIS operates under load impact condition, for FAPID algorithm, the rise time is reduced by 0.27s, the maximum overshoot is reduced by 9.83mm, and the absolute value of average error is decreased by 62.62% compared with PID control algorithm. The response speed of SMC is the fastest, but there is a large chattering in the steady-state displacement. The designed FAPID control algorithm balances the advantages of fast response, high control precision and good stability, and the control performance is better than that of SMC and PID control algorithms. The research methods in this paper can provide reference value for position control accuracy improvement of hydraulic suspension.

Transient flow behaviors of the check valve with different spool-head angle in high-pressure hydrogen storage systems

The strong collision problem of check valve, caused by the high-pressure hydrogen flow, is one major problem in the high-pressure hydrogen storage systems. Understanding of the transient flow behaviors and the impact of the hydrogen gas flow is important for the safety of check valve in hydrogen storage systems. Based on the transient CFD method and the moving mesh technology, the transient hydrogen flow model for the check valve is established. It has been proved by the comparison between the result of simulation and experiment. The flow characteristics at different moment during the opening process is studied, and the movement of the spool of the check valve is also analyzed. Moreover, several transient hydrogen gas flow models with different spool-head angle are established, and effect of the spool-head angle on the movement performance of the valve spool and flow field characteristics is investigated. The results show that the acceleration, velocity and kinetic energy the spool hits the stopper increase by 7%, 16%, and 33% when the spool-head angle increases from 10° to 50°, which enhance the impact effect of the valve spool. This work obviously has a potential benefit for the structural optimization and application of the check valve in the high-pressure hydrogen storage systems.

Rheological Characterization and EHL Simulation of a Grease in a Lubricated Sealing Contact

This contribution provides an insight into the tribological behavior of grease-lubricated contacts in pneumatic spool valves. As the properties of the grease are strongly non-Newtonian, multiple measurements were performed to parameterize two viscosity models, the Herschel-Bulkley and the Palacios-Palacios model. These models are integrated into an EHL simulation of the sealing contact and qualitatively compared for two temperatures. For that system, the total friction force is rather unaffected by the choice of the viscosity model. In addition, qualitatively similar results with about 10 % deviation from the non-Newtonian behavior could be obtained using a Newtonian approximation of the lubricant.

Control Performance Improvement of Hydro-Viscous Clutch Based on Fuzzy-PID Controller

As a rotational speed controller, a hydro-viscous clutch (HVC) is usually used in the constant pressure water supply system to maintain the needed water pressure constant. However, when the hydro-viscous clutch is working, it often suffers from the problem of output rotational speed fluctuation since the spool of proportional relief valve can easily get stuck. Consequently, water pressure will fluctuate too. A special pump control system of HVC was proposed based on the Fuzzy-PID controller for the purpose of reducing the fluctuation rate. The MATLAB simulation was carried out according to the mathematical model and the results show that the Fuzzy-PID control strategy is superior to traditional PID control. The corresponding experiment was performed and the result indicate that through applying the Fuzzy-PID controller based pump control system, the rotational output speed fluctuation of HVC can be inhibited from ±60π to ±6π rad/min, and the water pressure fluctuation is dropped from ±0.1 to ±0.002 MPa.

Internal Leakage Predicition of Hydraulic Spool valves Based on Acoustic Emission Technology

In order to realize the nondestructive testing (NDT) of the internal leakage fault of hydraulic spool valves, the internal leakage rate must be predicted by AE (acoustic emission) technology. An AE experimental platform of internal leakage of hydraulic spool valves is built to study the characteristics of AE signals of internal leakage and the relationship between AE signals and leakage rates. The research results show the AE signals present a wideband characteristic. The main frequencies are concentrated in 30~50 kHz and the peak frequency is around 40 kHz. When the leakage rate is large, there are significant signal characteristics appearing in the high frequency band of 75~100 kHz. The exponent of the root mean square(RMS) of AE signals is positively correlated with the exponent of the leakage rate only if the leakage rate is greater than 2~3 mL/min. This find could be used to predict the internal leakage rate of hydraulic spool valves.

Transient simulation and experiment validation on the opening and closing process of a ball valve

The ball valve is an important device in the pipeline transportation system of nuclear power plants. Its operational stability and safety directly affect the normal working of nuclear power plants. In this study, the transient numerical simulation of the opening and closing process of a ball valve was conducted on the basis of the flow interruption capability experiment of the ball valve by using the moving mesh method and inlet and outlet variable boundary conditions. The flow rate and pressure difference with time of the opening and closing process of the ball valve were studied. The internal flow characteristics of the ball valve under different relative openings were analyzed in conjunction with the typical back-step flow structure. Results show that the transient numerical results agree well with the experimental results. The internal flow characteristics of the ball valve are similar at the same opening during opening and closing process. At small opening, the spool and outlet channels easily form a back-step flow structure. The disappearance and generation of backflow vortices during opening and closing occur at 85% opening and 75% opening, respectively. With the decrease in opening degree, the difference in vortex core area in the flow channel of the ball valve spool in the opening and closing process gradually appears. The research results provide some reference value for the design and optimization of ball valves.

Design of control valve with low energy consumption based on Isight platform

The pressure drop of a control valve is directly associated with the energy consumption of the control system. The conventional design method of a control valve results in high energy consumption, while the control ability deviates from the design goal. Additionally, repeated corrections via flow experiments are inefficient. To efficiently design a low-energy-consumption control valve that satisfies control requirements, a novel design method is proposed herein. It is parametrically defined in Sculptor software based on the conventional valve spool. Various software packages are integrated using script files in the Isight platform. An approximate model is constructed using sample points generated based on the design of experiments; subsequently, it is solved using an optimization algorithm. Simulation results indicate that the output pressure of the pump and the average pressure drop of the control valve decrease by 4.38% and 5.51%, respectively, under the same flow rate. The working flow characteristics curve exhibits high linearity, implying that energy conservation is realized while the control ability is improved. Moreover, the force on the valve spool decrease by 1.36% on average, while the pressure and velocity in the flow field are reduced.

ПРИМЕНЕНИЕ ЭЛЕКТРОТЕХНОЛОГИЙ ДЛЯ ВОССТАНОВЛЕНИЯ ДЕТАЛЕЙ СЕЛЬСКОХОЗЯЙСТВЕННОЙ ТЕХНИКИ

The technology of non-galvanized ironing of parts in the electrolyte flow with simultaneous hydromechanical activation of the plated surface is proposed, its advantages over the traditional type of coating are shown. The technological process of coating hydraulic control valve spools has been developed. The technological process of restoring spools consists of the following operations: preliminary surface preparation (mechanical treatment), degreasing, washing, anodic treatment, electrodeposition and final mechanical treatment. The designs of the installation and the electrochemical cell for ironing hydraulic control valve spools, providing optimal hydrodynamic conditions when applying coatings on worn surfaces, are proposed. Optimal modes and composition of ironing electrolyte have been defined, providing a high rate of precipitation growth (1.5...3 mm/h), adhesion strength and wear resistance of coatings. Bench and field tests of hydraulic valves with restored spools were performed, which confirmed the results of laboratory studies and the high efficiency of the proposed technology.

Analysis of energy losses in a hydraulic load sensing proportional valve

The paper presents modeling and simulation of a hydraulic proportional valve PVG 32 by Danfoss widely used in agricultural machinery. A suitable mathematical model is created in LMS Amesim and SolidWorks Flow simulation software programs with the analysis of its energy performance. Their outcomes are validated with the experimental results to correctly describe the real valve characteristics. Since the spool valves are designed with overrunning loads in mind, considerable throttling losses are observed in the discharge line when the machine is operating with a resistive load.Therefore; this paper suggests the possibility of implementing energy saving techniques in the valve by using independent metering and gives simulation model for further use.

Pengaruh Penggunaan Filter Non Original Terhadap Kerusakan Bucket Control Valve Excavator 320D

The hydraulic oil filter is one of the components contained in the hydraulic system which functions to filter the impurities contained in the oil so that it does not circulate into the system. The purpose of this study was to determine the performance of the original and non-original filters in relation to the damage that occurred to the control valve. The results indicated that the damage to the spool valve was caused by hydraulic oil contaminated with water, resulting in corrosion on its surface. Visual inspection of the hydraulic oil filter reveals particles found in the filer element.

Influences of Control Parameters on Reduction of Energy Losses in Electrohydraulic Valve with Stepping Motors

In many heavy machines, the use of high force drives is required. For such tasks, electrohydraulic servo drives with proportional valves are used most often. In these valves, the proportional electromagnets are applied. If high precise control is additionally required, it is necessary to use expensive servo valves or precise stepping motors. In this paper, the application of a valve with one (or with two) stepping motors in the electrohydraulic servo drive is described. Such motors may work in a micro-step mode, which enables the precise positioning of the valve spool with low energy consumption. The control system structure that was used for positioning, consisting of such an electrohydraulic servo drive with a valve having stepping motors, is described. In the investigations, the following control parameters are considered: the number of stepping motors used, proportional gain coefficients, supply pressure, and desired step distance. The simulation model of the servo drive is proposed, enabling the investigations of energy consumption during the positioning process. In the investigations, the drive step responses are recorded and compared, taking into account the rise time and energy consumption. The overshot-free algorithm is used in the following step and tested in positioning tasks. The collected results of energy consumption of the drive during the positioning process are compared with other solutions.

Digital Twin-Driven Mating Performance Analysis for Precision Spool Valve

The precision spool valve is the core component of the electro-hydraulic servo control system, and its performance has an important influence on the flight control of aviation and aerospace products. The non-uniform surface topography error causes a non-uniform mating gap field inside the spool valve, which causes oil leakage and leads to deterioration of the spool valve performance. However, the current oil leakage calculation method only considers the influence of size errors, which is not comprehensive. Thus, how to characterize the mating behavior of the spool valve and its effect on oil leakage with consideration of surface topography errors is the key to evaluating the performance of the spool valve. This paper proposes a new way of analyzing the mating performance of precision spool valves, which considers the surface topography errors based on digital twin technology. Firstly, a general framework for the analysis of mating performance of precision spool valve based on a digital twin is proposed. Then, key technologies of assembly interface geometry modeling, matching behavior modeling and performance analysis are studied. Finally, a quantitative correlation between the mating parameters and the oil leakage of the precision spool valve is revealed. The method is tested on a practical case. This proposed method can provide theoretical support for the accurate prediction and evaluation of the mating performance of the precision spool valve.

Robust μ-Controller for Hydraulic Spool Valve, Pilot Operated with Switching Micro Valves

Hydraulic spool valve, pilot operated with bi-state switching micro valves is a low-cost alternative to the conventional proportional and high-response valves. However, high-frequency switching causes variations in the control flow which limits achievable spool tracking error. This paper presents the design of a robust μ-controller for the spool position reference tracking synthesized with D-K iterative procedure. Furthermore, in order to reduce wind-up effects in the closed-loop, the μ-controller is decomposed to a canonical observer and state feedback components which allows explicit introduction of the saturated control signal in the controller equations. The uncertainty model required for the μ-synthesis is inferred from the nonlinear hydraulic model by identification of a Box–Jenkins model set characterized by its parameter covariance matrix. The regulator is implemented in a 32-bit programmable logic controller (PLC) and its performance is experimentally verified on a laboratory test bench of electro-hydraulic power steering system.

Analysis of the Movement Characteristics of the Pump Valve of the Mine Emulsion Pump Based on the Internet of Things and Cellular Automata

Studying the movement characteristics of the coalmine emulsion pump valve is of great significance for optimizing the dynamic response characteristics of the pump valve, reducing the hysteresis effect, and improving the volumetric efficiency. This article combines the Internet of Things (IoT) and cellular automata techniques to investigate the movement characteristics of the valve of the emulsion pump. Based on Adolf’s exact differential equation and Runge–Kutta iterative method, the movement displacement and movement of the pump valve spool speed curve are computed using Scilab software. We employ cellular automata and AMESim to establish the hydraulic system model of emulsion pump and analyze the movement characteristics of pump valve movement displacement, speed, stability, and closing hysteresis through simulation. Finally, the IoT techniques and a test device are used to evaluate the movement displacement of the pump valve. The experimental results verify the feasibility of using the proposed method to study the pump valve motion characteristics, greatly reduce the cost of testing and parameterized design, and contribute to the development of highly reliable and efficient emulsion pump valves.