Servo valve endurance test for water-hydraulic systems in ITER-relevant conditions

2019 ◽  
Vol 146 ◽  
pp. 2523-2526 ◽  
Author(s):  
Liisa Aha ◽  
Jukka Väyrynen ◽  
Jyrki Tammisto ◽  
Jouni Mattila ◽  
Salvador Esqué ◽  
...  
Keyword(s):  
Hydraulic Systems ◽  
Endurance Test ◽  
Servo Valve ◽  
Water Hydraulic

Development of the Servo Valve with High Durability Using Split-Type Sleeve – Reduction of Wear with Ceramic Material –

2019 ◽  
Vol 31 (5) ◽  
pp. 707-714
Author(s):  
Koki Sakakibara ◽  
◽  
Shunya Suzuki ◽  
Kazushi Shibata ◽  
Yuto Sawada ◽  
...  
Keyword(s):  
Ceramic Material ◽  
Ceramic Materials ◽  
Hydraulic Systems ◽  
Servo Valve ◽  
High Durability ◽  
Water Hydraulic

Reduction of leakage is a major problem in water hydraulic systems. With a servo valve, it is possible to reduce the internal leakage by reducing the clearance between a spool and a sleeve. However, because the clearance is reduced, wear tends to occur easily between the spool and sleeves when the servo valve is driven. As a result, the durability of the servo valve is reduced. Attention is paid to the durability against wear of ceramic materials, and the wear can be suppressed by using ceramics as the materials of the spool and sleeve. Thus, one can check whether the wear between the spool and sleeve can be suppressed, thereby improving the durability of the servo valve.

Heat management for water-hydraulic systems at ITER remote handling

2019 ◽  
Vol 146 ◽  
pp. 2314-2318 ◽  
Author(s):  
J. Väyrynen ◽  
L. Aha ◽  
J. Mattila ◽  
S. Esqué ◽  
R. Sharratt
Keyword(s):  
Hydraulic Systems ◽  
Heat Management ◽  
Remote Handling ◽  
Water Hydraulic

Development of the Small Flow Rate Water Hydraulic Servo Valve

2010 ◽  
Vol 22 (3) ◽  
pp. 333-340 ◽  
Author(s):  
Toshiya Watanabe ◽  
◽  
Tomokazu Inayama ◽  
Takeo Oomichi
Keyword(s):  
Flow Rate ◽  
Servo Valve ◽  
Test And Evaluation ◽  
Small Flow Rate ◽  
Hydraulic Servo ◽  
Small Flow ◽  
Hydraulic Manipulator ◽  
Water Hydraulic ◽  
Leakage Characteristics ◽  
Small Capacity

A small capacity servo valve was developed for a small size water hydraulic manipulator, focusing the saving energy. The new servo valve optimizes the machines small flow rate use, makes the stroke longer for wideband use, reduces leakage and makes control easier. The test and evaluation of the servo valve was conducted by examining flow rate characteristics, leakage characteristics and responsibility. The flow rate and leak rate of the servo valve shows to be the same as the oil hydraulic servo valve, while the step and frequency response show good controllability for the water hydraulic manipulator.

scholarly journals EXPERIENCES ON THE LOW PRESSURE WATER HYDRAULIC SYSTEMS

1999 ◽  
Vol 1999 (4) ◽  
pp. 357-363 ◽  
Author(s):  
Jussi AALTONEN ◽  
Kari KOSKINEN ◽  
Matti VILENIUS ◽  
Pekka KUNTTU
Keyword(s):  
Low Pressure ◽  
Hydraulic Systems ◽  
Pressure Water ◽  
Water Hydraulic

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.

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