Device and method for optically detecting particles in a free liquid stream

A device for optically detecting particles in a free liquid stream, said device comprising:

• a liquid nozzle for providing a smooth free liquid stream capable of having particles therein;
• a laser for providing a laser beam that intersects said liquid free stream at a sensing region so that particles in said free liquid stream cause scattering of light at said sensing region;
• a light collector for collecting said scattered light at said sensing region, said light collector being positioned to collect scattered light at an angle of about 65.degree. with respect to said free liquid stream;
• a detector for receiving light collected by said light collector and providing an electrical signal output indicative thereof;
• and
• a signal processor for receiving said electrical signal output from said detector and responsive thereto providing an output indicative of at least one of size and number of particles causing said light scattering at said sensing region.

A device for optically detecting particles in a free liquid stream, said device comprising:

• a liquid nozzle for providing a smooth free liquid stream capable of having particles therein, said free liquid stream having predetermined first and second regions that are spaced from one another along said free liquid stream;
• a wall having a surface in the path of said free liquid stream so that said free liquid stream contacts said surface of said wall, and wherein said second region is adjacent to said surface of said wall;
• a laser for providing a laser beam that intersects said free liquid stream at said first region such that particles in said free liquid stream at said first region cause light scattering that travels along said liquid free stream from said first region to said second region;
• a light collector for collecting scattered light at said second region;
• and
• a processing unit for receiving said scattered light collected by said light collector and, responsive thereto, providing an output indicative of at least one of size and number of particles causing said light scattering at said first region.

A method for optically detecting particles in a free liquid stream, said method comprising:

• providing a free liquid stream capable of having particles therein, said free liquid stream having predetermined first and second regions that are spaced from one another along said free liquid stream;
• directing light to intersect said free liquid stream at said first region so that particles in the free liquid stream at said first region scatter light that travels along said free liquid stream from said first region to said second region;
• collecting light at said second region that is scattered by particles in the free liquid stream at said first region;
• and
• providing an output based upon the collected light scattered by the particles in the free liquid stream at said first region with said output being an output indicative of at least one of size and number of said particles.