A Multi-purpose Micro Fluid Power Component using Ultrasonic Vibration (2nd Report: Quantitative Evaluation of Mixing and Pumping Characteristics)

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.

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Hydraulic fluid power. Component cleanliness. Guidelines for achieving and controlling cleanliness of components from manufacture to installation

10.3403/02689390 ◽

2002 ◽

Keyword(s):

Fluid Power ◽

Hydraulic Fluid ◽

Power Component

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Fluid Power Component and Sensor Diagnostics Using an Expert System Shell

10.4271/901642 ◽

1990 ◽

Author(s):

D. J. Creber ◽

J. Watton

Keyword(s):

Expert System ◽

Fluid Power ◽

Expert System Shell ◽

Power Component

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Identification of Fluid Power Component Behaviour Using Dynamic Flowrate Measurement

Proceedings of the Institution of Mechanical Engineers Part C Journal of Mechanical Engineering Science ◽

10.1243/pime_proc_1995_209_141_02 ◽

1995 ◽

Vol 209 (3) ◽

pp. 179-191 ◽

Cited By ~ 5

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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