scholarly journals A Multi-purpose Micro Fluid Power Component using Ultrasonic Vibration

2010 ◽  
Vol 41 (1) ◽  
pp. 8-13
Author(s):  
Jun GOMI ◽  
Kenjiro TAKEMURA
Keyword(s):  
Ultrasonic Vibration ◽  
Fluid Power ◽  
Power Component

Analytical Method for Defining Pressure Compensator Dynamics

2000 ◽  
Author(s):  
Timo J. Käppi ◽  
Asko U. Ellman
Keyword(s):  
Fluid Power ◽  
Time Domain Simulation ◽  
First Order ◽  
Lack Of Information ◽  
Valve Dynamics ◽  
Accepted Practice ◽  
Component Models ◽  
Hydraulic Valves ◽  
Power Component ◽  
Stationary Behavior

Abstract Computer simulation is a powerful and generally accepted practice to carry out research in the area of fluid power. However, accurate parameterization of the component models is required to achieve correct simulation results. The parameters describing the stationary behavior of hydraulic valves are easily available from valve manufacturers’ catalogues. The dynamics are presented typically for the servo valves only. The dynamics of pressure valves are usually more or less unknown even for the manufacturers. Numerical values for simulation purposes are very rarely available. The lack of information concerning valve dynamics makes the component measurements unavoidable. This is time consuming and costly and the benefits of simulation concept in general are reduced. In this paper a method for defining first order dynamics for the pressure compensator is presented. This method can be used in time-domain simulation of fluid power components and systems. The method is based on the analytical dimensions of valve such as diameter of damping orifice, spring constant and mass. Pressure compensated mobile valve is measured for method verification. The presented method can be applied to any type of commercially available well damped single-stage pressure valves. It makes the fluid power component parameterization considerably easier and thereby the advantages reached by simulation are increased.

Identification of Fluid Power Component Behaviour Using Dynamic Flowrate Measurement

1995 ◽  
Vol 209 (3) ◽  
pp. 179-191 ◽  
Author(s):  
J Watton ◽  
Y Xue
Keyword(s):  
Experimental Approach ◽  
Fluid Power ◽  
Pressure Relief Valve ◽  
Relief Valve ◽  
Nitrogen Gas ◽  
Pressure Relief ◽  
Dynamic Impedance ◽  
State Pressure ◽  
Power Component ◽  
Impedance Magnitude

An identification concept is developed utilizing direct measurement of the transient flowrate and pressure to determine the dynamic characteristics of fluid power components. The fundamental experimental approach is discussed and applied to a range of sizes of a bladder-type accumulator and also to a single-stage pressure relief valve. The gas charging characteristic of the accumulator was determined for three different sizes and during dynamic operation. It is shown how the nitrogen gas index of compression varies during operation and a relationship between the index and instantaneous flowrate is proposed. Measurements obtained with the pressure relief valve were used to identify its dynamic impedance in the frequency domain via time series analysis and transformation. The predictions are compared with a linearized mathematical model showing good correlation over a wide frequency band. A particular feature was found to be the use of the impedance magnitude-frequency asymptotes for validation of the steady state pressure-flowrate characteristic.

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