Meteorlogical Particle Sensor

The Meteorological Particle Sensor (MPS) system, manufactured by Droplet Measurement Technologies Inc., is an Optical Array Probe (OAP) designed to measure rain droplet size particles. The OAP style measurement system uses a photo-diode array to sense the presence (and size) of droplets as they pass through the measurement region. A laser transmitter provides the coherent light source making it possible for the probe to clearly distinguish light blockage. The MPS system was originally design to measure rain droplets within the range of 100mm to 6200mm, with a 100mm resolution.

The MPS system provides a direct method to sample droplet size of larger size sprays. The PADS software includes validation and correction routines that account for transit time (droplet velocity) and measurement volume/depth of field considerations.

In addition to the droplet counts which are collected and provided by the MPS – PADS system software, Spraying Systems Co. has written post-processing software to assess the drop size distribution and calculate additonal statistical values. The post-processing software provides standard droplet size statistics such as D10, D32, Dv0.1, Dv0.5, Dv0.9, and Relative Span Factor (RSF). The terminal velocity of the droplets is also calculated and can be of great use in assessing sprays which involve a long ‘fall’ time after initial breakup.

The MPS system measures large, often non-spherical, droplets generated by high flow nozzles.