Displacement Characteristics of Variable Hydraulic Transformer

2014 ◽  
Vol 543-547 ◽  
pp. 741-746 ◽  
Author(s):  
Guan Zhong Yang ◽  
Ji Hai Jiang
Keyword(s):  
Flow Rate ◽  
Load Flow ◽  
Hydraulic Transformer ◽  
Swash Plate

A new kind of hydraulic transformer, called variable hydraulic transformer (VHT), has been proposed to control its load flow rate. The displacement characteristics of VHT are investigated in detail. The mathematic models are concluded and optimized. Matlab is used to simulate and calculate, finding that there are 5 controlled angles of the port plate that can help define displacement characteristics of VHT. The relationships between the displacement characteristics and the structure in VHT are shown. The results demonstrate the performance laws of VHT when the controlled angles of the port plate and of the swash plate change.

Development of a Novel High Pressure Electronic Pneumatic Pressure Reducing Valve

2010 ◽  
Vol 133 (1) ◽  
Author(s):  
Xu Zhipeng ◽  
Wang Xuanyin
Keyword(s):  
High Pressure ◽  
Flow Rate ◽  
Closed Loop ◽  
Mechanical Design ◽  
Mathematic Model ◽  
Load Flow ◽  
Pneumatic Pressure ◽  
Output Pressure ◽  
Novel Structure ◽  
Pressure Reducing Valve

Pressure reducing valve (PRV) is one of the critical components in high pressure pneumatic systems. Nowadays, manually operated PRVs have been widely used, but there is still no universal electronic PRV. Thus, we proposed a novel high pressure electronic pneumatic pressure reducing valve (EPPRV) whose inlet pressure (pi) is up to 31.5 MPa. The EPPRV mainly consists of a poppet structured pilot valve and a piston structured main valve. A proportional electromagnet was used as the command element, and a pressure closed loop, rather than a force closed loop controller, was designed. First, the mechanical design and functionality of the EPPRV are carefully analyzed. Then, a mathematical model is built up, and the working characteristics of pressure, flow rate, and frequency response are simulated. Finally, the test bench is introduced, and detailed experiments are carried out. Simulated and experimental results are highly consistent within output pressure (po) ranging from 8 MPa to 25 MPa and load flow rate (qld) ranging from 60 g/s to 650 g/s, which verifies the feasibility of the novel structure and the validity of the mathematic model.

Four-port hydraulic transformer with inlet and outlet equal flow and its flow characteristics

2021 ◽  
pp. 095440622110316
Author(s):  
Chu Zhang ◽  
Lianquan Zhou ◽  
Xiaonan Bo ◽  
Weiwei Qu ◽  
Panpan Zang
Keyword(s):  
Theoretical Analysis ◽  
Flow Rate ◽  
Hydraulic System ◽  
Measurement Data ◽  
Flow Characteristics ◽  
Remarkable Feature ◽  
Flow Rates ◽  
Instantaneous Flow ◽  
Hydraulic Transformer ◽  
System A

Without changing the original valve control hydraulic system, a kind of hydraulic transformer, called four-port hydraulic transformer (FHT), is proposed to recover the energy loss caused by system throttling. The remarkable feature of FHT is that the flow rate at inlet and outlet ports are equal. This means that FHT can be connected into the load circuit of hydraulic system to recovery energy without refreshing flow rate. This paper investigates the flow characteristics of FHT, including instantaneous flow rates, average flow rates and flow pulsations in each port. The relationships between the structure of port plate and the flow characteristics are given. The variation rule of number of plungers connected to four ports is shown, and the relationship between the variation and the flow pulsation is revealed. The simulation results show that the flow rates and displacements of symmetrical ports are same, and the instantaneous flow rate of symmetrical ports has the same rule. The results also show the frequent changes of the number of plungers connected with each port lead to more flow jump points in instantaneous curves, and the jump point is the basic cause of its loud noise. The test shows that the flow rates of measurement data of the experiment are very close to the theoretical analysis, proved the theoretical analysis of flow characteristics for FHT are appropriate and reasonable, which has a certain reference for the development and energy-saving application for FHT.

scholarly journals Research on the Pressure Ratio Characteristics of a Swash Plate-Rotating Hydraulic Transformer

Energies ◽  
2018 ◽  
Vol 11 (6) ◽  
pp. 1612 ◽  
Author(s):  
Chongbo Jing ◽  
Junjie Zhou ◽  
Shihua Yuan ◽  
Siyuan Zhao
Keyword(s):  
Pressure Ratio ◽  
Hydraulic Transformer ◽  
Swash Plate

Kinematic Analysis of a Swash-Plate Controlled Variable Displacement Axial-Piston Pump With a Conical Barrel Assembly

2009 ◽  
Vol 132 (1) ◽  
Author(s):  
Zhiru Shi ◽  
Gordon Parker ◽  
Jonathan Granstrom
Keyword(s):  
High Pressure ◽  
Frequency Analysis ◽  
Flow Rate ◽  
Piston Pump ◽  
Flow Ripple ◽  
Swash Plate ◽  
Piston Displacement ◽  
Output Flow ◽  
Variable Displacement ◽  
Axial Piston

Variable displacement, swash-plate controlled, axial-piston pumps are widely used in applications that require high pressure and variable flow rates. The pump consists of a rotating barrel assembly that houses several pistons in a circular array. A swash-plate is used to control the displacement of the pistons to adjust the output flow of hydraulic fluid. As the barrel rotates, the pistons slide along the angled swash-plate and draw oil from the supply and then discharge oil into the high pressure circuit. This results in an almost constant output flow rate. This paper analyzes the kinematics of a pump based on its geometry dependent characteristics. The analysis assumes an idealized case in which there is no oil leakage and the fluid is considered to be incompressible. It is revealed through the analysis that the piston displacement and the pump output flow are slightly increased by using a conical barrel. Instantaneous and mean flow rate equations are used to describe the output flow characteristics and flow ripple effect. The output flow rate ripple profile is found to be a function of both swash-plate angle and the conical barrel angle. A term defined as the flow rate uniformity coefficient is used to better quantify the flow ripple phenomenon. A frequency analysis is performed on the output flow rate and an additional order is found to be present when using a conical barrel pump versus one with a cylindrical barrel when the pumps have an odd number of pistons. Conical barrel piston pumps are found to have a slight increase in piston displacement, velocity, and acceleration relative to the rotating barrel frame of reference over a pump with a cylindrical barrel. This translates into an increase in the output flow rate for a conical piston pump under the same operating conditions. The conical barrel is also found to have a reduction in the rotational inertia allowing for faster angular acceleration. The presence of an extra order from a frequency analysis for a conical pump with an odd number of pistons has the potential to cause unwanted noise or vibration to the structure or components attached to the pump.

scholarly journals Effect of Rotation Speed and Flow Rate on Slip Factor in a Centrifugal Pump

2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
Bo Chen ◽  
Baolin Song ◽  
Bicheng Tu ◽  
Yiming Zhang ◽  
Xiaojun Li ◽  
...  
Keyword(s):  
Centrifugal Pump ◽  
Flow Rate ◽  
Rotation Speed ◽  
Internal Flow ◽  
Load Flow ◽  
Optical Measurements ◽  
Centrifugal Pumps ◽  
Pump Impeller ◽  
Slip Factor ◽  
Deviation Coefficient

This work analyzes the causes of the slip phenomenon in the impeller on the basis of the internal flow mechanism. Detailed optical measurements of the flow inside the rotation passages of a five-bladed centrifugal pump impeller are obtained through particle image velocimetry (PIV). On the basis of experimental data, the deviation coefficient of slip velocity is proposed and then revised according to the slip factor calculation formula of Stechkin. Results show that, at the same rotation speed, the slip factor increases with the flow rate and reaches the maximum value at 1.0 QBEP flow rate. At different rotation speeds, the slip factor increases with the rotation speed and shows a relatively large variation range. Moreover, a revised slip factor formula is proposed. The modified model is suitable for the correction of slip factor at part-load flow rates and serves as a guide for the hydraulic performance design and prediction of centrifugal pumps.

Modelling of the Cross Angle and its Impact on Pump Performance

2021 ◽  
Author(s):  
Andris Rambaks ◽  
Katharina Schmitz
Keyword(s):  
Flow Rate ◽  
Volumetric Flow Rate ◽  
Great Success ◽  
Pump Performance ◽  
Flow Ripple ◽  
The Past ◽  
Swash Plate ◽  
Simulation Results ◽  
The Cross ◽  
Pressure Controlled

Abstract A secondary swash plate angle, also known as a cross angle, has been used in the past to reduce flow ripple with great success. However, for the past two decades, research in this field has been scarce. In this paper, a pressure controlled 9-piston pump is investigated to determine the effects of the cross angle on commutation, acting forces and torques, as well as volumetric flow rate pulsations. A detailed description of the piston kinematics, the simulation model used, and the subsequent simulation results are presented in this contribution.

Simulation and Analysis on Load-Sensing Swash Plate Piston Pumps Based on AMESim

2014 ◽  
Vol 631-632 ◽  
pp. 723-727 ◽  
Author(s):  
Lan Tang ◽  
Zhuo Qing Li ◽  
Tao Tao Gao
Keyword(s):  
Flow Rate ◽  
Rotation Speed ◽  
Steering System ◽  
Piston Pump ◽  
Load Sensing ◽  
Swash Plate ◽  
Set Up ◽  
Different Parts

Relations between different parts are analyzed based on the structure of load-sensing swash plate piston pump. The models of piston pump and the servomechanism are set up by AMESim and connected with load-sensing steering system. The pressure and flow rate response under different rotation speed without priority valve is researched. The result shows such piston pump model can always response quickly and provide reasonable pressure and flow rate that fit the steering demands.

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