Particle Counter with Laser Diode

Abstract

A liquid particle counter for optically detecting an unconstrained particle suspended in a flowing liquid includes a sample chamber having a liquid inlet and a liquid outlet; a laser diode module producing a symmetrically collimated laser beam; a beam shaping optical system directing the laser beam at the sample chamber; and an optical detector located to detect light scattered by the particle in the sample chamber, the detector producing an electric signal characteristic of a parameter of the particle. The laser beam has an energy of a watt or more and passed through an aperture in a black glass aperture element in the sample chamber. The black glass aperture element removes diffracted and stray light from the beam without damage to the sample chamber.

1 . A device for optically detecting an unconstrained single particle suspended in a flowing liquid, said device comprising:
 a sample chamber having a liquid inlet and a liquid outlet, said sample chamber adapted to permit said single particle to flow essentially without constraint between said inlet and outlet;   a laser diode module producing a symmetrically collimated laser beam;   a beam shaping optical system directing said laser beam at said sample chamber; and   an optical detector located to detect light scattered by said particle in said sample chamber, said detector producing an electric signal characteristic of a parameter of said particle.   
   
   
       2 . A device as in  claim 1  wherein said device is a non-in-situ particle counter. 
   
   
       3 . A device as in  claim 2  wherein said device is a volumetric particle counter. 
   
   
       4 . A device as in  claim 1  wherein said device is an in-situ particle counter. 
   
   
       5 . A device as in  claim 1  wherein said sample chamber includes a glass or crystalline aperture element having an aperture and said beam shaping system directs said laser beam through said aperture. 
   
   
       6 . A device as in  claim 5  wherein said glass or crystalline aperture element is made of light-absorbing glass or light-absorbing crystalline material. 
   
   
       7 . A device as in  claim 6  wherein said glass or crystalline aperture element is made of NG1 black glass or black diamond. 
   
   
       8 . A device as in  claim 5  wherein said device includes a light baffle chamber, and said glass aperture element is located between said light baffle chamber and said sample chamber. 
   
   
       9 . A device as in  claim 5  wherein said light baffle chamber is fluidly connected to said inlet and outlet to permit said liquid to flow through it. 
   
   
       10 . A device as in  claim 1  wherein said laser diode module a unique m.o.d.e.™ laser diode module. 
   
   
       11 . A device as in  claim 1  wherein said beam shaping optics includes an aperture system blocking a third or more of the power of said laser beam. 
   
   
       12 . A particle counter for optically detecting an unconstrained single particle suspended in a flowing liquid, said particle counter comprising:
 a sample chamber having a liquid inlet and a liquid outlet, said sample chamber having a plastic wall and adapted to permit said single particle to flow essentially without constraint between said inlet and said outlet;   a glass or crystalline aperture element having an aperture and located in said plastic sample chamber wall;   a laser diode module producing a laser beam;   a beam shaping optical system directing said laser beam through said aperture into said sample chamber; and   an optical detector located to detect light scattered by said particle in said sample chamber, said detector producing an electric signal characteristic of a parameter of said particle.   
   
   
       13 . A device as in  claim 12  wherein said glass or crystalline aperture element is made of black glass or black crystal. 
   
   
       14 . A method of manufacturing a liquid particle counter, said method comprising:
 providing a plastic sample chamber having a black glass or black crystalline aperture element having an aperture;   flowing a liquid containing an unconstrained particle through said sample chamber;   providing a laser beam;   directing said laser beam through said aperture;   collecting light scattered by said particle in said liquid; and   providing an output based on said collected light scattered by said particle detected in said flowing liquid.   
   
   
       15 . A method as in  claim 14  and further comprising cooling said black glass or black crystalline aperture element with said fluid flow.