The technique of mesh obscuration for debris monitoring — the COULTER LCM II

Abstract

Debris monitoring of fluid power systems can now be performed by the technique of mesh obscuration. The contaminated fluid is passed through a fully characterised filter mesh under constant, laminar flow conditions. Particles larger than the effective pore size of the mesh are retained on its surface and-reduce the open area available for flow. The upstream pressure rises in proportion to the number of particles retained, because of increasing degree of mesh obscuration. If several different meshes are used, a particle count distribution may be obtained at Industry Standard size levels. This simple principle ensures that the results are independent of colour or opacity of the fluid. Contamination such as water does not effect the results.

The COULTER® LCM II is a fully automatic instrument which may be operated throughout a wide temperature range. Particle counts are obtained at size levels of 5, 15 and 25µm, with fluid viscosity and temperature also reported. The COULTER LCM II has low pressure on-line capability, together with fully programmable remote control and data transmission via a standard computer interface. Programmable count thresholds for all particle size levels and viscosity may be used to indicate, and/or act upon set required sample conditions. This rugged and portable instrument is also suitable for batch sampling either in the Laboratory or at remote sites.

Performance results are presented for Industry Standard calibration materials, and for typical debris monitoring applications, including linearity, accuracy and repeatability data.

The flexibility of the COULTER LCM II and the simplicity of the mesh obscuration principle will enable this highly innovative instrument to be easily integrated into any debris monitoring program.