Research on the performance of electro-hydraulic proportional flow valve controlled by active pilot pump

2016 ◽  
Vol 231 (4) ◽  
pp. 720-731 ◽  
Author(s):  
Yunxiao Hao ◽  
Long Quan ◽  
Jiahai Huang
Keyword(s):  
Pressure Differential ◽  
Small Displacement ◽  
Flow Pulsation ◽  
Pump Speed ◽  
Pump Flow ◽  
Flow Capacity ◽  
Flow Through ◽  
Large Flow ◽  
Proportional Flow ◽  
Flow Valve

The cartridge flow valves, used in heavy machine and equipment, have the advantages of low leakage, large flow capacity, simple structure, and ease of modulation. However, in order to reduce the influence of load variety on the flow through valve, a pressure differential compensator or a cartridge type flow sensor should be added to the proportional throttle valve. These methods have disadvantages of reducing the flow capacity of valve and increasing the throttling loss. To overcome these disadvantages, a low energy consumption, high controllable electro-hydraulic proportional flow valve which consists of a hydraulic transistor (Valvistor) and a small displacement hydraulic pump driven by a servo motor is proposed firstly in the world. As the pump flow is basically proportional to the pump speed and little influenced by load variety, the flow through main valve is proportional to pilot pump speed. In the research, it’s known that feedback throttle slot pre-opening will cause the decrease of the main valve flow as pressure drop increases. So, small orifices are used instead of the pre-opening of feedback throttle slot to reduce the influence of load variety on the flow through valve. Furthermore, a method of pressure differential changing with pilot pump rotational speed calibration is introduced to further mitigate the influence of pressure difference. In this paper, the mathematical dynamic model of the valve is also established and the stability criterion of valve is derived. The influence of valve parameters and the flow pulsation of pilot pump on valve flow performance is analyzed and simulated. In view of the pilot pump flow pulsation frequency being much higher than the valve natural frequency, the research shows that the influence of flow pulsation of pilot pump on valve flow performance is very little. The research work provides a new method for the large flow electro-hydraulic proportional control system.

The Design of Giant Magnetostrictive Flow Valve and its COMSOL Simulation

2010 ◽  
Vol 160-162 ◽  
pp. 1146-1150 ◽  
Author(s):  
Pei Chen ◽  
Quan Guo Lu ◽  
Ding Fang Chen ◽  
Kun Chen
Keyword(s):  
Fast Response ◽  
Flow Displacement ◽  
Magnetostrictive Strain ◽  
Valve Opening ◽  
Magnetostrictive Actuator ◽  
Comsol Simulation ◽  
Displacement Model ◽  
Large Flow ◽  
Pilot Valve ◽  
Flow Valve

By combining magnetostrictive actuator with flow valve directly, the flow was precisely controlled due to magnetic materials’ properties of fast response (less than 1μs)and large magnetostrictive strain (up to 1500ppm). The structure was designed based on this theory, and the flow - displacement model of valve was established by analyzing the size of the valve opening in different incentive current. The flow field was analyzed through multi-physics analysis software COMSOL. Simulation results showed that, the continuous adjustment and precision control were realized in a certain range of flow in the valve. Therefore, it could not only adjust the flow in micro amount directly, but also can be a pilot valve for high frequency precision large flow valve.

A Novel Control Strategy for Pilot Controlled Proportional Flow Valve With Internal Displacement-Flow Feedback

2018 ◽  
Vol 140 (11) ◽  
Author(s):  
He Wang ◽  
Xiaohu Wang ◽  
Jiahai Huang ◽  
Jun Wang ◽  
Long Quan
Keyword(s):  
Pressure Drop ◽  
Flow Rate ◽  
Control Strategy ◽  
Pid Controller ◽  
Back Propagation ◽  
Back Propagation Neural Network ◽  
Internal Displacement ◽  
Valve Opening ◽  
Proportional Flow ◽  
Flow Valve

The present study is focused on the construction of a well-performing pilot controlled proportional flow valve with internal displacement-flow feedback. A novel control strategy for the valve is proposed in which the flow rate through the valve is directly controlled. The linear mathematical model for the valve is established and a fuzzy proportional–integral–derivative (PID) controller is designed for the flow control. In order to obtain the flow rate used as feedback rapidly and accurately in real-time, back propagation neural network (BPNN) is employed to predict the flow rate through the valve with the pressure drop through the main orifice and main valve opening, and the predicted value is used as the feedback. Both simulation and experimental results show that the predicted value obtained by BPNN is reliable and available for the feedback. The proposed control strategy is effective with which the flow rate through the valve remains almost constant when the pressure drop through the main orifice increases and the valve can be applied to the conditions where the independence of flow rate and load is required. For the valve with the proposed control strategy, the nonlinearity is less than 5.3%, the hysteresis is less than 4.2%, and the bandwidth is about 16 Hz. The static and dynamic characteristics are reasonable and acceptable.

Maximum airflow through the nose in humans

1991 ◽  
Vol 70 (3) ◽  
pp. 1369-1376 ◽  
Author(s):  
J. Pertuze ◽  
A. Watson ◽  
N. B. Pride
Keyword(s):  
Peak Flow ◽  
Maximum Flow ◽  
Nasal Breathing ◽  
Flow Capacity ◽  
Maximum Expiratory Flow ◽  
Maximum Effort ◽  
Flow Through ◽  
Expiratory Flow ◽  
Nasal Flow ◽  
Alpha Adrenergic Agonist

Inspiratory and expiratory flow via the nose and via the mouth during maximum-effort vital capacity (VC) maneuvers have been compared in 10 healthy subjects. Under baseline conditions maximum flow via the nose was lower than that via the mouth in the upper 50-60% of the VC on expiration and throughout the VC on inspiration. The mean ratio of maximum inspiratory to maximum expiratory flow at mid-VC was 1.38 during mouth breathing and 0.62 during nasal breathing. Inspiratory flow limitation with no increase in flow through the nose as driving pressure was increased above a critical value (usually between 12 and 30 cmH2O) was found in all six subjects studied. Stenting the alae nasi in seven subjects increased peak flow via the nose from a mean of 3.49 to 4.32 l/s on inspiration and from 4.83 to 5.61 l/s on expiration. Topical application of an alpha-adrenergic agonist in seven subjects increased mean peak nasal flow on inspiration from 3.25 to 3.89 l/s and on expiration from 5.03 to 7.09 l/s. Further increases in peak flow occurred with subsequent alan stenting. With the combination of stenting and topical mucosal vasoconstriction, nasal peak flow on expiration reached 81% and, on inspiration, 79% of corresponding peak flows via the mouth. The results demonstrate that narrowing of the alar vestibule and the state of the mucosal vasculature both influence maximum flow through the nose; under optimal conditions, nasal flow capacity is close to that via the mouth.

scholarly journals Control Method of Slipstream Gas Source System of a Propeller

2019 ◽  
Vol 267 ◽  
pp. 01001
Author(s):  
Jinchun Shi
Keyword(s):  
Control Method ◽  
Low Flow ◽  
Source Control ◽  
Whole Process ◽  
Gas Source ◽  
Compressed Gas ◽  
Flow Through ◽  
Great Energy ◽  
Large Flow ◽  
Stable Control

For the slipstream gas source control system of propeller, there is no mature application in China. The traditional slipstream gas source system manually realizes the stable control of gas and flow through the self-operated pressure reducing device. But this mode can only be used in the condition of small pressure and low flow, cannot meet the actual need of high pressure and large flow, and cannot monitor and automatically control the energy consumption of compressed gas and heating equipment, resulting in great energy waste. Based on the actual engineering conditions, and according to the characteristics, user requirements and work flow of the slipstream gas source system, this paper describes a new control method for the slipstream gas source system of a propeller in detail, which solves the issue of automatic control in the whole process and realizes the key technical point, rapid stabilizing of airflow pressure and temperature.

Investigation on the modeling and dynamic characteristics of a fast-response and large-flow water hydraulic proportional cartridge valve

2020 ◽  
Vol 234 (22) ◽  
pp. 4415-4432
Author(s):  
Mingxing Han ◽  
Yinshui Liu ◽  
Kan Zheng ◽  
Youchun Ding ◽  
Defa Wu
Keyword(s):  
Genetic Algorithm ◽  
Flow Rate ◽  
Dynamic Characteristics ◽  
Fast Response ◽  
Dynamics Simulation ◽  
Multi Objective Optimization ◽  
Multi Objective ◽  
Flow Capacity ◽  
Water Hydraulic ◽  
Large Flow

In large-power and high-pressure hydraulic systems, the maximum instantaneous flow rate is often several thousand liters per minute. Normal proportional valves are often difficult to meet their requirements for large flow rate and fast response at the same time. And the leakage of hydraulic oil will seriously pollute the environment. Therefore, a novel water hydraulic proportional valve with fast response and high flow capacity is presented for the large transient power hydraulic system in this paper. The valve utilizes a two-stage structure with two 2/2-way water hydraulic proportional valves as the pilot stage and a cartridge poppet valve as the main stage to achieve fast-response and large-flow capacity simultaneously. A detailed and precise nonlinear mathematical model of the valve considering both structural parameters and flow force is developed. A comprehensive performance optimization has been carried out, which can be mainly divided into computational fluid dynamics simulation optimization based on reducing flow force and multi-objective optimization based on genetic algorithm. The effects of double U-grooves' parameters on the flow force (flow-induced loads) have been studied in detail by numerical simulation. Through the grooves geometry optimization, the maximum flow force can be reduced by 10%. Then, the influences of structure parameters on the performance of step response have been studied, and the optimal parameters of the valve have been obtained by multi-objective optimization based on genetic algorithm. The maximum overshoot has been reduced from 15% to 6% (about 60%) and the adjusting time has been reduced from 58 ms to 48 ms. The dynamic characteristics of the valve have been improved effectively. Finally, a test apparatus which has the ability to provide transient large flow is built. The accuracy of simulation model and optimization design method is verified by test results.

Optimal Construction of a Hydraulic Pump With Elliptic Rotated Piston by Kakeya-Besicovitch Application

2007 ◽  
Author(s):  
Petru Ungur ◽  
Petru A. Pop ◽  
Mircea Gordan ◽  
Nicodim Muresan
Keyword(s):  
Spindle Speed ◽  
Original Position ◽  
Hydraulic Motor ◽  
Hydraulic Pump ◽  
Constant Length ◽  
Variable Volume ◽  
Flow Capacity ◽  
Elliptical Section ◽  
Large Flow ◽  
Optimal Construction

The paper has presented an application of Kakeya-Besicovitch, third example about commutation of finite element beam endpoints inside of arbitrary small zone. This area is a hypocycloid with three cusped points at that inner tangent has a constant length independent by the point position of its inner tangent, which being rotated in clock-way it’s came back to its original position with its endpoints reversed. The application is a hydraulic pump compound by one rotated piston with elliptical section which is rolling in a fixed chamber with hypocycloid form and three cusped rounded tips after a curvature equal with major axe ellipse endpoints curvatures. The rolling motion is imposed by eccentric exterior source that acting inside of cylindrical pocket located in the center of elliptic piston, which divided the hypocycloid in three equal parts at 120° from each other. The pump could be working as a hydraulic motor which is endowed with rotating distributor that can feed each chamber with variable volume one by one due to moving the piston. The pump’s relevance is given by its efficiency, allowing a large flow capacity to a lower spindle speed, ensured a constant ratio spindle speed which working silence and a large stability.

scholarly journals Modeling nutrient consumptions in large flow-through bioreactors for tissue engineering

2009 ◽  
Vol 103 (5) ◽  
pp. 1003-1015 ◽  
Author(s):  
Mamatha Devarapalli ◽  
Benjamin J. Lawrence ◽  
Sundararajan V. Madihally
Keyword(s):  
Tissue Engineering ◽  
Flow Through ◽  
Large Flow

Affinity pump system: a new peristaltic blood pump for cardiopulmonary bypass

Perfusion ◽  
2000 ◽  
Vol 15 (1) ◽  
pp. 77-83 ◽  
Author(s):  
C Jaggy ◽  
M Lachat ◽  
B Leskosek ◽  
G Zünd ◽  
M Turina
Keyword(s):  
Blood Flow ◽  
Cardiopulmonary Bypass ◽  
In Vitro Study ◽  
Pump System ◽  
Ventricular Assist ◽  
Pump Speed ◽  
Pump Flow ◽  
Pump Chamber ◽  
Time Flow

An in vitro study has been carried out to assess the pump performance of a new peristaltic, extracorporeal displacement pump (Affinity) for cardiopulmonary bypass. The pump system consists of a pump rotor (0-110 rpm), a pump chamber, a venous reservoir with a 5/8″ connecting tube and the Affinity console. The polyurethane chamber is connected to the venous reservoir by a 5/8″ tube and fills passively due to the hydrostatic pressure exhibited by the fluid height in the venous reservoir. The implementation of an occlusive segment in the pump chamber, which collapses in low filling states, should prevent significant negative pressures. An in vitro circuit was filled with bovine blood (37°C, hematocrit 35%) and the pump flow was measured by an ultrasonic transit time flow probe with respect to pre-load, diameter and length of attached tubing in the venous line, pump speed (rpm) and size of the connecting tube (3/8″ and 5/8″). At 108 rpm and a preload equal to 10 mmHg, the flow was 8.6 ± 0.42 l/min for an afterload of 80 mmHg. The reduction of the inlet connector to 3/8″ diminished the pump flow significantly to 5.2 ± 0.31 l/min ( p < 0.0001). The pump flow decreased linearly with respect to the length of the attached tube in the venous line and for a 2 m long 5/8″ silicon tube, the rpm-optimized flow was still 6.0 ± 0.28 l/min at a preload of 10 mmHg. In case of low filling state or too high rpm, the occlusive segment collapsed and no cavitation bubbles could be detected. Our in vitro measurements yield a nomogram for rpm-optimized blood flow with respect to the pre-load in the venous reservoir. The delivered 5/8″ connecting tube facilitates optimum filling of the pump chamber for high blood flow, but limits the use of venous reservoirs to Affinity products. The pump yields a high blood flow even when long tubing in the venous line is used. This makes the pump a candidate for a ventricular assist device. In hypovolemia or high rpm, the occlusive segment collapses and no negative pressure is generated at the inflow site of the pump chamber.

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