Particle counter (PAMAS OLS 4031)
Optical particle counters work with the help of light. In optical measurement proceedings, the light beams through the liquid. The electromagnetic waves may be deflected or absorbed when meeting the particles in the measuring cell. The light effect on the particles is analysed with the help of a previously calibrated optical electronic hardware. There are two basic principles of contamination analysis: the principle of Light Extinction and the principle of Light Scattering.
According to the principle of Light Extinction, the liquid flows through the measuring cell of the sensor. The size of the measuring cell is different for each application. On one side of the measuring cell, there is a light beam, on the other side there is a photodetector. If there are particles in the liquid, then the light beam hits the particles and as a result, the shadow of the particle is shown on the photo-detector. The surface of the shadow causes a voltage change on the photodetector and indicates the size of the particle flowing through the sensor cell. The particle counter transfers the number of shadows on the photo-detector into the quantity of particles in the liquid. Furthermore, the particle sizes are distributed in different size classes.
The PAMAS OLS4031 particle counter is a equipment for fluid condition monitoring and is equipped with up to 32 size channels which can be selected by the user and adjusted to the individual specific application. The PAMAS OLS4031 is operated with the PAMAS PMA software for Particle Measuring and Analysis. Particle sensor of this instrument is equipped with the light extinction sensor PAMAS HCB-LD-50/50. The abbreviation HCBLD of the sensor stands for High Concentration Blockage - Laser Diode, i.e. for a sensor using an integrated laser diode as light source. The integrated laser diode has a wavelength of 670 nm. The numbers integrated in the sensor name refer to the size of the measuring cell: the sensor PAMAS HCB-LD-25/25 for instance has a cell size of 250 μm x 250 μm. This sensor operate with a nominal flow rate of 25 ml per minute and a maximum particle concentration of 125000 particles per ml at a coincidence rate of 7,8%. This Particle sensors could a measure in a range from 1 µm up to 200 µm.
