Effect of Pump Inlet Conditions on Hydraulic Pump Cavitation: A Review

2008 ◽  
pp. 318-318-15
Author(s):  
RJ Bishop ◽  
GE Totten
Keyword(s):  
Hydraulic Pump ◽  
Inlet Conditions ◽  
Pump Inlet

Intermittently Operated Oil Hydraulic Pump Unit With Accumulator to Save Energy and Hydraulic Assist for Restart

2013 ◽  
Author(s):  
Katsumasa Suzuki ◽  
Shinpei Ota ◽  
Shuji Kasuya ◽  
Ken Sugimura
Keyword(s):  
Energy Saving ◽  
Electric Power ◽  
Electric Motor ◽  
Combustion Engine ◽  
Electricity Consumption ◽  
Duty Ratio ◽  
Hydraulic Motor ◽  
Hydraulic Pump ◽  
Pump Unit ◽  
Pump Inlet

Efforts to conserve energy have been made in a number of fields due to a shortage of energy resources, such as oil, and the need to protect the Earth’s environment. In the field of hydraulics, energy-saving pump units are very important because they consume less energy. At present, variable displacement type hydraulic pump units (VD pump units) and inverter control type pump units (INV pump units) are widely used. The authors propose using an intermittently operated pump unit coupled with an accumulator (ACC pump unit). It is verified that the ACC pump unit is superior to the others in terms of efficiency, especially when the flow rate to the load is small or the duty ratio for the intermittent work is low. However, the stop/restart operation of the electric motor for the pump drive is repeated frequently, and the instantaneous electric power consumed by the electric motor is more than six times the rated electricity when the pump is restarted. Therefore, we decreased the excess electricity consumption at pump restart using a method called “hydraulic assist”. Before the electric motor is turned on, high-pressure fluid is supplied to the pump inlet from the accumulator. The pressure at the pump outlet is made to be zero by opening the valve to the tank. The pump essentially works as a hydraulic motor. Then, the electric motor is turned on. In this method, the instantaneous electric power consumption is reduced. This method is also applied to a hydraulic pump unit driven by an internal combustion engine. The intermittent operation of the engine-driven hydraulic pump unit was accomplished using hydraulic assist to restart the pump. In this report, the energy-saving characteristics are shown.

Limiting Inlet Conditions for Phase Change Avoidance in Supercritical CO2 Compressors

2019 ◽  
Author(s):  
Timothy C. Allison ◽  
Aaron McClung
Keyword(s):  
Mach Number ◽  
Phase Change ◽  
Supercritical Co2 ◽  
High Reliability ◽  
Full Range ◽  
Phase Region ◽  
Two Phase ◽  
Inlet Conditions ◽  
Pump Inlet ◽  
Static Conditions

Abstract In many supercritical CO2 cycle implementations, compressor or pump inlet conditions are relatively near the two-phase region. Fluid acceleration near the compressor inlet can result in the potential for condensation or cavitation at the inlet. Despite potential mitigating effects or evidence in the literature, potential two-phase operation is a high-risk condition and may not be recommended for high-reliability system design. This paper presents a summary of the existing literature documenting inlet phase change in sCO2, and presents an analysis of required conditions to avoid phase change as a function of inlet pressure, temperature, and Mach number. Static conditions at the inlet are calculated based on the real gas approach documented in ASME PTC-10, Appendix G. In addition, various total-to-static iteration challenges are discussed and avoided through solution of the inverse problem to convert limiting static conditions at saturation to the full range of limiting total conditions for various Mach numbers up to 1.0. The results show that a threshold total temperature exists above which phase change cannot occur, ranging from 31.1 to 66.95 °C and increasing with Mach number. Lower temperatures below this threshold may also avoid phase change depending on the total pressure. The documented results are useful as a reference for use by cycle designers to impose design limits that minimize risks associated with two-phase flow in the compressor.

Application of ultra-high molecular weight polyethylene in a hydraulic drive

2020 ◽  
pp. 77-78
Keyword(s):  
Molecular Weight ◽  
Low Temperature ◽  
High Molecular Weight ◽  
Hydraulic Drive ◽  
Control Valve ◽  
Hydraulic Control ◽  
Hydraulic Motor ◽  
Hydraulic Pump ◽  
Hydraulic Oil ◽  
Ultra High Molecular Weight

The use of ultra-high molecular weight polyethylene (UHMW PE) for the manufacture of various parts, in particular cuffs for hydraulic drives, is proposed. The properties and advantages of UHMW PE in comparison with other polyethylene materials are considered. Keywords ultra-high molecular weight polyethylene, hydraulic pump, hydraulic motor, hydraulic control valve, hydraulic oil, low temperature. [email protected]

scholarly journals Assessment of Mini-Tablets Coating Uniformity as a Function of Fluid Bed Coater Inlet Conditions

Pharmaceutics ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 746
Author(s):  
Magdalena Turk ◽  
Rok Šibanc ◽  
Rok Dreu ◽  
Maja Frankiewicz ◽  
Małgorzata Sznitowska
Keyword(s):  
Coating Layer ◽  
Spectrophotometric Analysis ◽  
Material Distribution ◽  
Spray Chamber ◽  
Colorimetric Analysis ◽  
Swirl Generator ◽  
Coating Uniformity ◽  
Fluid Bed ◽  
Inlet Conditions

This study concerned the quality of mini-tablets’ coating uniformity obtained by either the bottom spray chamber with a classical Wurster distributor (CW) or a swirl distributor (SW). Mini-tablets with a diameter of 2.0, 2.5, and 3.0 mm were coated with hypromellose using two different inlet air distributors as well as inlet airflow rates (130 and 156 m3/h). Tartrazine was used as a colorant in the coating layer and the coating uniformity was assessed by spectrophotometric analysis of solutions obtained after disintegration of the mini-tablets (n = 100). Higher uniformity of coating material distribution among the mini-tablets was observed in the case of SW distributor, even for the biggest mini-tablets (d = 3.0 mm), with an RSD no larger than 5.0%. Additionally, coating thickness was evaluated by colorimetric analysis (n = 1000), using a scanner method, and expressed as a hue value. A high correlation (R = 0.993) between inter-tablet variability of hue and UV-Vis results was obtained. Mini-tablets were successfully coated in a fluid bed system using both a classical Wurster distributor as well as a swirl generator. However, regardless of the mini-tablets’ diameter, better film uniformity was achieved in the case of a distributor with a swirl generator.

scholarly journals A Boom Energy Regeneration System of Hybrid Hydraulic Excavator Using Energy Conversion Components

Actuators ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 1
Author(s):  
Tri Cuong Do ◽  
Duc Giap Nguyen ◽  
Tri Dung Dang ◽  
Kyoung Kwan Ahn
Keyword(s):  
Management Strategy ◽  
Electrical Energy ◽  
Maximum Energy ◽  
Regeneration System ◽  
Hydraulic Pump ◽  
Energy Management Strategy ◽  
Energy Regeneration ◽  
System A ◽  
Time Optimal ◽  
Novel Design

In this paper, a novel design of an energy regeneration system was proposed for recovering as well as reusing potential energy in a boom cylinder. The proposed system included a hydraulic pump/motor and an electrical motor/generator. When the boom moved down, the energy regeneration components converted the hydraulic energy to electrical energy and stored in a battery. Then, the regenerated energy was reused at subsequent cycles. In addition, an energy management strategy has been designed based on discrete time-optimal control to guarantee position tracking performance and ensure component safety during the operation. To verify the effectiveness of the proposed system, a co-simulation (using MATLAB and AMESim) was carried out. Through the simulation results, the maximum energy regeneration efficiency could achieve up to 44%. Besides, the velocity and position of the boom cylinder achieved good performance with the proposed control strategy.

scholarly journals A Hydraulic Pump Fault Diagnosis Method Based on the Modified Ensemble Empirical Mode Decomposition and Wavelet Kernel Extreme Learning Machine Methods

Sensors ◽  
2021 ◽  
Vol 21 (8) ◽  
pp. 2599
Author(s):  
Zhenbao Li ◽  
Wanlu Jiang ◽  
Sheng Zhang ◽  
Yu Sun ◽  
Shuqing Zhang
Keyword(s):  
Fault Diagnosis ◽  
Extreme Learning Machine ◽  
Recognition Accuracy ◽  
Ensemble Empirical Mode Decomposition ◽  
Hydraulic Pump ◽  
Vibration Signals ◽  
Mode Decomposition ◽  
Diagnosis Method ◽  
Kernel Extreme Learning Machine ◽  
Learning Machine

To address the problem that the faults in axial piston pumps are complex and difficult to effectively diagnose, an integrated hydraulic pump fault diagnosis method based on the modified ensemble empirical mode decomposition (MEEMD), autoregressive (AR) spectrum energy, and wavelet kernel extreme learning machine (WKELM) methods is presented in this paper. First, the non-linear and non-stationary hydraulic pump vibration signals are decomposed into several intrinsic mode function (IMF) components by the MEEMD method. Next, AR spectrum analysis is performed for each IMF component, in order to extract the AR spectrum energy of each component as fault characteristics. Then, a hydraulic pump fault diagnosis model based on WKELM is built, in order to extract the features and diagnose faults of hydraulic pump vibration signals, for which the recognition accuracy reached 100%. Finally, the fault diagnosis effect of the hydraulic pump fault diagnosis method proposed in this paper is compared with BP neural network, support vector machine (SVM), and extreme learning machine (ELM) methods. The hydraulic pump fault diagnosis method presented in this paper can diagnose faults of single slipper wear, single slipper loosing and center spring wear type with 100% accuracy, and the fault diagnosis time is only 0.002 s. The results demonstrate that the integrated hydraulic pump fault diagnosis method based on MEEMD, AR spectrum, and WKELM methods has higher fault recognition accuracy and faster speed than existing alternatives.

scholarly journals Composite multi-scale basic scale entropy based on CEEMDAN and its application in hydraulic pump fault diagnosis

IEEE Access ◽  
2021 ◽  
pp. 1-1
Author(s):  
Xiaolin Liu ◽  
Xiaoqiang Yang ◽  
Faming Shao ◽  
Wuqiang Liu ◽  
Fuming Zhou ◽  
...  
Keyword(s):  
Fault Diagnosis ◽  
Hydraulic Pump ◽  
Multi Scale ◽  
Basic Scale

scholarly journals An EWT-PCA and Extreme Learning Machine Based Diagnosis Approach for Hydraulic Pump

2020 ◽  
Vol 53 (3) ◽  
pp. 43-47
Author(s):  
Yu Ding ◽  
Liang Ma ◽  
Chao Wang ◽  
Laifa Tao
Keyword(s):  
Extreme Learning Machine ◽  
Hydraulic Pump ◽  
Learning Machine ◽  
Diagnosis Approach
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