scholarly journals Bench tests of a support system of a powered roof support’s hydraulic leg aimed at minimizing consequences of leaks

2019 ◽  
Vol 134 ◽  
pp. 01003
Author(s):  
Dawid Szurgacz ◽  
Jarosław Brodny ◽  
Marcin Brzózka ◽  
Ryszard Diederichs
Keyword(s):  
High Pressure ◽  
Support System ◽  
Extraction Process ◽  
Main Element ◽  
Hydraulic Systems ◽  
Working Pressure ◽  
Bench Tests ◽  
Main Component ◽  
Valve Block ◽  
Roof Support

Effectiveness of a powered roof support significantly impacts on the efficiency and safety of a mining process. The main element of the support is a hydraulic leg which transfers loads imposed by the rock mass. One of the basic issues occurring during the extraction process are internal and external leaks of hydraulic systems. A new support system was designed to limit and later eliminate the consequences of such leaks. Its main component is a valve block equipped with two independent check valves. This solution allows to maintain high pressure in both chambers of a leg despite leaks. The article discusses the developed solution and presents preliminary results of bench tests of a leg equipped with the new block and loaded dynamically. The results are promising, and the tested block fulfils its task by maintaining the working pressure in the leg during load.

The Development of Ultra High-Pressure Hydraulic Systems

1947 ◽  
Vol 156 (1) ◽  
pp. 282-285 ◽  
Author(s):  
S. M. Parker
Keyword(s):  
Hydraulic Engineer ◽  
High Pressure ◽  
Industrial Design ◽  
Hydraulic Systems ◽  
Working Pressure ◽  
Ultra High Pressure ◽  
Specific Loading

Most engineers seek to reduce weight and bulk by the use of higher specific loading of their material. The hydraulic engineer is no exception to this; but his choice of working pressure determines to an unusually large extent the detail construction of most parts of the system. The purpose of this paper is to examine briefly the reasons which lie behind this choice of pressure, with particular reference to the possibility of using a higher working pressure than is in common use at present for the lighter forms of equipment in aircraft, automobile, and industrial design. Within the scope of this paper it will only be possible to examine the essentials of the problem, and to suggest likely solutions, with the knowledge that time and experience will probably provide other and better answers.

Enhancement of Anticancer Activity of Acer mono by High Pressure Extraction Process

2009 ◽  
Vol 38 (9) ◽  
pp. 1243-1252 ◽  
Author(s):  
Myoung-Hoon Jeong ◽  
Seung-Seop Kim ◽  
Ji-Hye Ha ◽  
Ling Jin ◽  
Hak-Ju Lee ◽  
...  
Keyword(s):  
High Pressure ◽  
Anticancer Activity ◽  
Extraction Process ◽  
Pressure Extraction ◽  
Acer Mono

Study on the Influence of Deformation of the Slipper of Axial Piston Pump under High Pressure on Oil Film Structure

2014 ◽  
Vol 900 ◽  
pp. 734-737 ◽  
Author(s):  
Huai Chao Wu ◽  
Yun Liu Yu
Keyword(s):  
High Pressure ◽  
Film Structure ◽  
Piston Pump ◽  
Axial Piston Pump ◽  
Working Pressure ◽  
Element Analysis ◽  
Oil Film ◽  
The Finite Element Analysis ◽  
Order Of Magnitude ◽  
Axial Piston

The stress and strain of the slipper of 35 MPa high pressure axial piston pump are analyzed by the finite element analysis method, and the following facts are revealed: in spite of the fact that the slipper can satisfy the use requirement in the aspect of stress, whereas, in the aspect of strain, the deformation of the bottom of the slipper increases with the pressure increase, and the deformation of the slipper has reached the order of magnitude of the oil film thickness under 35 MPa working pressure. Therefore, when the slipper pair of 35 MPa high pressure axial piston pump is designed and its oil film performances are studied, the influence of deformation of the slipper on the oil film structure must be considered comprehensively. The results of this study can provide some guides for developing 35 MPa high pressure axial piston pump.

Fluid for high-pressure hydraulic systems

1983 ◽  
Vol 19 (1) ◽  
pp. 35-36
Author(s):  
L. G. Konovich ◽  
A. S. Zhurba ◽  
A. P. Furman
Keyword(s):  
High Pressure ◽  
Hydraulic Systems

scholarly journals Data-driven Adaptive Thresholding Model for Real-time Valve Delay Estimation in Digital Pump/Motors

2020 ◽  
Author(s):  
Abdallah Chehade ◽  
Farid Breidi ◽  
Keith Scott Pate ◽  
John Lumkes
Keyword(s):  
High Pressure ◽  
Real Time ◽  
Domain Knowledge ◽  
Operating Conditions ◽  
Delay Model ◽  
Hydraulic Systems ◽  
Pressure Transducers ◽  
Statistical Behavior ◽  
Shift Detection ◽  
And Performance

Valve characteristics are an essential part of digital hydraulics. The on/off solenoid valves utilized on many of these systems can significantly affect the performance. Various factors can affect the speed of the valves causing them to experience various delays, which impact the overall performance of hydraulic systems. This work presents the development of an adaptive statistical based thresholding real-time valve delay model for digital Pump/Motors. The proposed method actively measures the valve delays in real-time and adapts the threshold of the system with the goal of improving the overall efficiency and performance of the system. This work builds on previous work by evaluating an alternative method used to detect valve delays in real-time. The method used here is a shift detection method for the pressure signals that utilizes domain knowledge and the system’s historical statistical behavior. This allows the model to be used over a large range of operating conditions, since the model can learn patterns and adapt to various operating conditions using domain knowledge and statistical behavior. A hydraulic circuit was built to measure the delay time experienced from the time the signal is sent to the valve to the time that the valve opens. Experiments were conducted on a three piston in-line digital pump/motor with 2 valves per cylinder, at low and high pressure ports, for a total of six valves. Two high frequency pressure transducers were used in this circuit to measure and analyze the differential pressure on the low and high pressure side of the on/off valves, as well as three in-cylinder pressure transducers. Data over 60 cycles was acquired to analyze the model against real time valve delays. The results show that the algorithm was successful in adapting the threshold for real time valve delays and accurately measuring the valve delays. 

New Generation of Brake Callipers to Improve Competitiveness and Energy Savings in Very High Performance Cars

2014 ◽  
Vol 217-218 ◽  
pp. 471-480
Author(s):  
Ivano Gattelli ◽  
Gian Luigi Chiarmetta ◽  
Marcello Boschini ◽  
Renzo Moschini ◽  
Mario Rosso ◽  
...  
Keyword(s):  
High Pressure ◽  
High Performance ◽  
Energy Savings ◽  
High Reliability ◽  
A357 Alloy ◽  
Bench Tests ◽  
Heat Treated ◽  
New Generation ◽  
Non Destructive ◽  
Very High

This paper concerns with the optimisation of the innovative rheocasting process to produce a new generation of brake callipers, characterised by very high reliability and strength. The attained very promising properties favoured their use on a very high performance car and the presented technique can be further extended for other important challenging applications. The prototype components are produced using T6 heat treated A357 alloy. Results on the samples machined directly from the produced callipers are in detail described and analysed. Pieces exhibiting some small defects, individuated by non-destructive tests, as well as defectless pieces have been underlined to severe industrial tests, e.g. high pressure tight, as well as severe bench tests, and it has been observed that the proposed technological process assure the fulfilment of the requirements contained in standards.

Hydraulic Components Contribution to Total Power Losses and Acceleration of an Open Loop System With Long Hose

2004 ◽  
Author(s):  
Michael Westman ◽  
Ove Isaksson
Keyword(s):  
Open Loop ◽  
Total Power ◽  
Hydraulic Systems ◽  
Power Losses ◽  
Hydraulic Motor ◽  
Hydraulic Pump ◽  
Pressure Losses ◽  
Forest Logging ◽  
Pipe Line ◽  
Valve Block

This paper is concerned with forest logging machinery. A great deal of final felling in cut-to-length method done by harvester, which fells, delimbs and cuts the trees to pre-selected lengths. Two important criteria of a harvester head are that it has to be energy efficient and it has to be as fast as possible. To minimize losses in hydraulic systems the main demand is to reduce pressure losses in high power valves and outer components as much as possible. Each orifice in the flow path results in power losses. This work is an experimental study on power losses and acceleration of hydraulic motor in a system with long hoses. Main hydraulic components included are hydraulic pump, cartridge valve, pipe line and hydraulic motor. The results show that pre-activating the pump improves the system speed. To reduce losses, optimization of valve block, cartridge valve orifices are needed. Accumulators are favourable if combined with high stand-by pressure.

scholarly journals Case Analysis of Damages to Control Hydraulics of the Leg in the Powered Roof Support Section

2019 ◽  
Vol 105 ◽  
pp. 03013
Author(s):  
Janina Świątek ◽  
Kazimierz Stoiński
Keyword(s):  
Coal Mining ◽  
Case Analysis ◽  
Hard Coal ◽  
Support Section ◽  
Full Extension ◽  
Safety Measures ◽  
Bench Tests ◽  
Hard Coal Mining ◽  
Roof Support

The article discusses a case of security hazard in a longwall equipped with a properly selected chock shield support with two legs, technically efficient, introduced to the market and for operation in compliance with the requirements covering Polish hard coal mining. As a cause of the hazard an accidental coincidence was indicated, such as the occurrence of a tremor at an area with unfavourable geometry for the operation of the support section and leg (including the shift of the double-telescopic leg from the 1st to the 2nd hydraulic stage) at the time of the mining process. Immediate safety measures were applied successfully. They were aimed at minimizing the conditions dangerous to the crew. The section was withdrawn and spragged again. As a result, the leg operated in full extension mode of the 1st hydraulic stage, obtaining the required strength and geometry of the section and leg. The presented case study will be additionally supplemented in the future with selected analytical and bench tests.

scholarly journals Stable Isolation of Phycocyanin from Spirulina platensis Associated with High-Pressure Extraction Process

2013 ◽  
Vol 14 (1) ◽  
pp. 1778-1787 ◽  
Author(s):  
Yong Seo ◽  
Woo Choi ◽  
Jong Park ◽  
Jin Park ◽  
Kyung-Hwan Jung ◽  
...  
Keyword(s):  
High Pressure ◽  
Spirulina Platensis ◽  
Extraction Process ◽  
Pressure Extraction
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