Microbial water quality and diversity in hydraulic systems using tap water as a pressure medium

2000 ◽  
Vol 41 (12) ◽  
pp. 215-222 ◽  
Author(s):  
S. M. Soini ◽  
K. T. Koskinen ◽  
M. Vilenius ◽  
J. A. Puhakka
Keyword(s):  
Hydraulic System ◽  
Tap Water ◽  
Pilot Scale ◽  
Hydraulic Systems ◽  
Water Hydraulics ◽  
Pressure Medium ◽  
Viable Bacteria ◽  
Water Hydraulic ◽  
Cell Densities

Water hydraulics uses tap water or demineralised water as a pressure medium and has fewer environmental impacts than oil-using hydraulics. The applicability is restricted by the microbial quality of the medium. The objectives of this study were to determine whether microbes grow in the pressure medium of a water hydraulic system, biofilm is formed on the surfaces and to describe the diversity of bacteria that survive and grow in water hydraulic systems. A pilot-scale water hydraulic system was used in the experiments. The viable counts in the pressure medium increased in three days from 102 to 3 ×104 cfu/ml followed by a gradual decrease towards the steady-state concentration of 6× 1034 cfu/ml. The total cell numbers decreased from 3×105 to 2 ×104 cells/ml during the three weeks of operation indicating attachment onto the system surfaces as biofilms. The biofilm cell densities on collector slide surfaces varied between 7 ×103 and 1.2 ×104 cells/cm2 after 21 days of operation. The phosphatase activity in the pressure medium was in conformity with the numbers of viable bacteria. The enzymatic activities (α- and β- glucosidase, phosphatase, aminopeptidase) varied between 0.4 and 300 nmol/lh. The diversity of bacteria growing in the system was wide and differed from that of tap water.

scholarly journals Modeling and calculation of hydromechanical systems dynamics based on the volume rigidity theory

2018 ◽  
Vol 226 ◽  
pp. 01001 ◽  
Author(s):  
Alexander T. Rybak ◽  
Mikhail P. Shishkarev ◽  
Alexander A. Demyanov ◽  
Viktor P. Zharov
Keyword(s):  
Numerical Experiment ◽  
Hydraulic System ◽  
Shock Absorber ◽  
Rigidity Theory ◽  
Hydraulic Systems ◽  
Functional Parameters ◽  
Working Medium ◽  
Drive Systems ◽  
Volume Rigidity

A method for modeling hydraulic systems of hydromechanical devices based on the application of the volume rigidity theory - the property of the hydraulic system to keep its volume unchanged when the pressure of the working medium changes is proposed. The main analytical dependencies intended for modeling the hydraulic system are presented. An example of simulation and calculation of a hydromechanical shock absorber system which confirms the correctness and convenience of using the volume rigidity theory in modeling hydromechanical drive systems of complex machines is presented. The results of the numerical experiment make it possible to evaluate the functioning quality of the drive system under investigation to reveal the effect of the main design and system functional parameters on its operation. The graphs of the change in the main functional parameters of the shock absorber under investigation in real time are given, which make it possible to visually evaluate the results of a numerical experiment and draw conclusions about the need for modernization.

Development of Water Hydraulic System

2016 ◽  
Vol 819 ◽  
pp. 596-600
Author(s):  
Mohd Noor Asril Saadun ◽  
Ahmad Anas Yusof ◽  
Mohd Syukran Ismail
Keyword(s):  
System Performance ◽  
Hydraulic System ◽  
Operation Time ◽  
Control Valve ◽  
Pressure Control ◽  
Effect Of Temperature ◽  
Maximum Pressure ◽  
Water Pump ◽  
Pressure Medium ◽  
Water Hydraulic

Common hydraulic system using hydraulic oil as their working medium but there is an application using water due to high accessibility and environmentally concern.Water hydraulic is an attractive technology to use water as the pressure medium in hydraulic system. In this paper, water hydraulic system is design and develops that capable to use water as pressure medium. Water is used to provide clean environment and safe for the mobile purpose. The system includes electric motor, water pump, directional control valve, pressure control valve and motor hydraulic. Some of water challenged as the pressure medium in hydraulic system were considered during build and design the system to minimize the bad effect of water in hydraulic system. Besides, the arrangement of hydraulic components on the test rig also considered to optimize the water hydraulic system performance. Water hydraulic system performance was analyzed by measured maximum pressure produced from water pump and system efficiency. Others, the effect of temperature increment in water hydraulic system also analyzed to optimize operation time.

Research on the Flow and Cavitation Characteristics of Multi-Stage Throttle in Water-Hydraulics

2006 ◽  
Vol 220 (2) ◽  
pp. 99-108 ◽  
Author(s):  
Liu Yinshui ◽  
Yang Yousheng ◽  
Li Zhuangyun
Keyword(s):  
Power Systems ◽  
Tap Water ◽  
Operating Conditions ◽  
Two Stage ◽  
Hydraulic Power ◽  
Cavitation Damage ◽  
Water Hydraulics ◽  
Multi Stage ◽  
Working Medium ◽  
Water Hydraulic

In water-hydraulic power systems cavitation is more likely to happen than in oil-hydraulic power systems because of the high vaporous pressure of water. A multi-stage throttle, which consists of two or more orifices in a throttle, is an effective way to avoid or reduce cavitation damage. In this research, the cavitation characteristics of two-stage throttles are analysed theoretically and compared with a single-stage. Then, experiments are conducted to investigate the flow and cavitation characteristics of multi-stage throttles including two kinds of two-stage throttles and one of a three-stage kind. All the experiments are carried out under the two cases with and without backpressure, respectively. The working medium is tap water. Experimental results show that the shape of the multi-stage throttle and operating conditions have remarkable effects on the flow and cavitation characteristics.

PI Control of Proportional Valve-Cylinder Water Hydraulic System

2014 ◽  
Vol 548-549 ◽  
pp. 977-984
Author(s):  
Xin Ba ◽  
Xiao Hui Luo ◽  
Xu Feng Zhao ◽  
Yu Quan Zhu
Keyword(s):  
Hydraulic System ◽  
Tap Water ◽  
Dead Zone ◽  
Response Speed ◽  
Hydraulic Cylinder ◽  
Fast Response ◽  
Pi Control ◽  
Proportional Valve ◽  
Working Medium ◽  
Water Hydraulic

Water hydraulic components have been developed rapidly in recent years. However many problems such as low lubricity and leakage limited the performance of them, especially water proportional valves. A proportional valve- hydraulic cylinder system with tap water as working medium is chosen as object to investigate the performance of water hydraulic system. With regarding to the weaknesses of the selected 4/3 proportional valve including lag, dead zone and nonlinearity, an integral separation PI arithmetic based close-loop controller is developed. Experiments results verified the electro-hydraulic proportional system of fast response speed and high accuracy.

Development of a proportional poppet-type water hydraulic valve

2009 ◽  
Vol 223 (9) ◽  
pp. 2099-2107 ◽  
Author(s):  
S-H Park
Keyword(s):  
Dynamic Characteristics ◽  
Pulse Width ◽  
Simple Structure ◽  
Pulse Width Modulation ◽  
Tap Water ◽  
Environmental Problems ◽  
Hydraulic Systems ◽  
Water Hydraulic ◽  
Type Water ◽  
Hydraulic Valve

To address the environmental problems and the safety of hydraulic systems, the development of novel water hydraulic systems using working fluids such as tap water are being developed successfully. In this study, we aim to develop a proportional water hydraulic valve using a proportional poppet as the main valve, which has an on—off function as well as a proportional function. The proposed proportional poppet-type water hydraulic valve has a simple structure with a control orifice that passes to the pilot orifice at both sides of the conventional poppet. Experiments verified that the relation between the main flowrate and pilot flowrate of the developed valve is linear and that the dynamic characteristics of the proportional poppet are satisfactory. Also, the developed valve was verified to be suitable for pulse width modulation (PWM) control and practical use for the control of water hydraulic systems.

A Miniature On/Off Valve Concept for High Performance Water Hydraulics

2017 ◽  
Author(s):  
Miika Paloniitty ◽  
Matti Linjama
Keyword(s):  
High Performance ◽  
Control Valve ◽  
Hydraulic Control ◽  
Used Oil ◽  
Water Hydraulics ◽  
Starting Point ◽  
Pressure Medium ◽  
Water Hydraulic ◽  
Valve Control ◽  
Hydraulic Valve

Digital hydraulic control valve technology has shown its strengths in providing reliable, leak-tight and high performance valve control regardless of the pressure medium used, oil or water. This is enabled by the intelligent use of robust on/off seat valves. However, the availability of these valves for water hydraulics is limited, especially that of compact valves, which are needed for digital valve systems. Thus, with the aim to create a compact digital water hydraulic valve system, this paper presents the development process of a water hydraulic miniature valve. The starting point for the development is a previously developed miniature valve for oil hydraulics. Experimental results with the new prototype show that good performance can be achieved for the miniature valve even with using stainless steel materials. This enables high-performance digital water hydraulic control.

scholarly journals Vibrations of water hydraulic systems – an experimental approach

2019 ◽  
Vol 85 ◽  
pp. 06006
Author(s):  
Andrei Dragomirescu ◽  
Carmen-Anca Safta ◽  
Nicolae Orăşanu ◽  
Ioan Magheţi ◽  
Lucian Mândrea
Keyword(s):  
Experimental Study ◽  
High Frequency ◽  
Hydraulic System ◽  
Experimental Approach ◽  
Cavitating Flow ◽  
Hydraulic Systems ◽  
Butterfly Valve ◽  
Flow Rates ◽  
Drive Motor ◽  
Water Hydraulic

This paper presents an experimental study of the vibrations induced both by cavitating and by non-cavitating flow in a hydraulic installation that comprises the main elements of a water hydraulic system. The cavitation was triggered by progressively closing a butterfly valve. The vibrations were measured on the pump, on the bearings housing, on the pump drive motor, and at nine measurement points located upstream and downstream of the main elements of the installation. The measurements were carried out at different flow rates obtained at different openings of the butterfly valve. The results suggest that the phenomena that take place inside the pump and inside the bearings cause vibrations having frequencies of up to 10 kHz. The results also indicate that the cavitation that occurs at the butterfly valve causes vibrations of high frequency, above 3 kHz, that have a distinct peak at about 18 kHz. These results could be useful in establishing proper maintenance plans for hydraulic installations.

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