Patent ID: 7839493

Claim:
An apparatus for measuring a concentration level of impurity particulates in water, comprising: a laser beam generator for generating and outputting a laser beam having a predetermined frequency; an output control unit for controlling an output of the laser beam, the output control unit including a filter disposed in a laser beam path of the laser beam generator, a motor for rotating the filter, and a controller for controlling an operation of the motor, the filter selected from a variable density filter, a polarization optic, and a wedge optic, the filter capable of adjusting an output intensity of the laser beam upon changing a position by rotation of the motor to control the output of the laser beam to a constant level; a beam splitter for splitting a route of the laser beam output through the output control unit into two paths; a laser beam measurement unit for measuring the output intensity of the laser beam split from the beam splitter and outputting the measured value as an electrical signal; a condensing lens for condensing the laser beam split from the beam splitter; a sample cell for storing a water sample and being positioned in the laser beam path to receive irradiation of the condensed laser beam; a beam stopper for absorbing the condensed laser beam to prevent an external leakage of light; an acoustic sensor coupled to the sample cell, for measuring a sound generated from the sample cell due to collision of the condensed laser beam against impurity particulates in the sample water, and outputting the measured sound value as an electrical signal; and a control unit for receiving the electrical signal of the acoustic sensor, calculating a concentration level of impurity particulates in the water sample, and outputting a device control signal to the motor to rotate the filter to a desired position in order to adjust the output intensity of the laser beam.