Technical Article

Detection principle of solid particle contamination level in hydraulic oil

With the progress of science and technology, the contrast method and microscope counting method gradually leave people's sight due to the shortcomings of large error and long test time. The progressiveness detection principle of the light shielded automatic particle counter is increasingly accepted by people. Its detection principle is as follows:

The characteristic of the shading type automatic particle counter is to directly detect particles in oil by utilizing the shading performance of particles. The principle is shown in Figure 1. The suspended particles in the oil flow through a small transparent channel along with the oil, and a parallel laser beam that is perpendicular to the direction of oil flow and has been conditioned by a precision optical system is irradiated onto the transparent channel to form a window. When there are no particles in the transparent channel and laser beam, the laser receiver will receive all the laser passing through the window; When particles flow through the shading window, a portion of the laser will be blocked by the particles or reduced due to scattering, reflection, etc., resulting in a decrease in the amount of laser reaching the laser receiver. The attenuation of the laser is directly proportional to the particle size, which is the projected area of the particles in the laser beam. The laser received by the laser receiver undergoes photoelectric conversion, signal amplification, and other processes before entering the automatic particle counter host for further processing.