초록 ▼

Apparatus for analyzing particles contained in a fluent edium (12). The apparatus includes a body (20) having a window (30), an optical source preferably comprising a laser diode (100) having a small light emitting area (140), and an optical system (102) for focusing the light from the laser diode a

Apparatus for analyzing particles contained in a fluent edium (12). The apparatus includes a body (20) having a window (30), an optical source preferably comprising a laser diode (100) having a small light emitting area (140), and an optical system (102) for focusing the light from the laser diode at a focal spot (84) such that the size of the focal spot is approximately equal to the size of the light emitting area of the laser diode. A photodetector (106) is mounted in the body and detects light backscattered from the focal spot by particles in the fluent medium, and produces an electrical signal that comprises a series of pulses associated with the particles. The electrical signal is input to a detector that counts the pulses and indicates the number of particles in the fluent medium. The detector includes discrimination means for preventing the counting of a pulse that has a rise or fall time above a predetermined threshold, thereby discriminating against particles that are not at the focal spot. Means are provided for measuring the integrated amplitude of the electrical signal, and for varying the distance between the focal spot and the window to maximize such integrated amplitude. An intrinsically safe embodiment is also disclosed in which the probe positioned at the measuring site does not include any electrical components. This embodiment may be implemented using light of multiple wavelengths for characterizing individual particles.

대표청구항 ▼

An apparatus for analyzing particles contained in a fluent medium, the apparatus comprising: a body including a window; illumination means mounted to the body, the illumination means comprising an optical source and an optical system for receiving light from the optical source and focusing the light

An apparatus for analyzing particles contained in a fluent medium, the apparatus comprising: a body including a window; illumination means mounted to the body, the illumination means comprising an optical source and an optical system for receiving light from the optical source and focusing the light at a focal spot adjacent to the window in the fluent medium, the illumination means including means for adjusting the distance between the focal spot and the window; photodetector means for detecting pulses of light resulting from the backscattering of light by particles in the focal spot, and for producing a corresponding electrical signal; and detection means connected to receive the electrical signal, the detection means including size measurement means for measuring the length of time that individual particles are in the focal spot and for thereby providing an indication corresponding to the size of particles in the fluent medium, the detection means further including means for producing an integrated amplitude signal having a magnitude corresponding to the average amplitude of the electrical signal, whereby said distance may be adjusted based upon the integrated amplitude signal.