water - production and distribution United Kingdom

... consists of a laser and a detector placed inside a measurement cell. Water is passed through a measurement cell, and when the particles present in the water pass in front of the laser, they block the laser beam, creating a signal interruption on the detector. These interruptions, measured by the detector opposite the laser beam, are equivalent (or nearly so) to the number of particles, and the length of the interruption created when the particle blocks the beam is proportional to the size of the particle.