Optical test device for particle counting

Claim 1

A TEST DEVICE FOR PARTICLE COUNTING MECHANISM COMPRISING A. A LIGHT SOURCE B. A FIRST LIGHT ENERGIZABLE TRANSDUCER POSITIONED TO RECEIVE LIGHT FROM SAID SOURCE C. A FIXED DISPLACEMENT PUMP FOR MOVING A FIXED SAMPLE VOLUME CONTAINING PARTICLES TO BE COUNTED THROUGH A LIGHT BEAM PASSING FROM SAID LIGHT SOURCE TO THE TRANSDUCER, THE PARTICLES PASSING THROUGH SAID BEAM SUBSTANTIALLY ONE AT A TIME AND THE TRANSDUCER PRODUCING AN ELECTRICAL IMPULSE EACH TIME A PARTICLE PASSES THROUGH THE BEAM, D. A MOTOR FOR DRIVING SAID PUMP, E. AN ELECTRICAL CIRCUIT TO RECEIVE ELECTRICAL IMPULSE AND TO INDICATE THE NUMBER OF IMPULSES RECEIVED, F. A SECOND TRANSDUCER ENERGIZABLE BY LIGHT FROM A LIGHT SOURCE, G. MEANS FOR PERIODICALLY INTERRUPTING THE PASSAGE OF LIGHT FROM SAID LIGHT SOURCE TO THE SECOND TRANSDUCER, SAID MEANS BEING ACTUATED BY THE PUMP MOTOR, AND H. A SWITCH FOR CONNECTING THE FIRST AND SECOND TRANSDUCERS ALTERNATELY TO THE CIRCUIT FOR RECEIVING ELECTRICAL IMPULSES AND INDICATING THEIR NUMBER WHEREBY THE NUMBER OF IMPULSES PRODUCED BY THE FIRST TRANSDUCER DURING MOVEMENT OF THE PUMP MOTOR TO MOVE A FIXED SAMPLE VOLUME CAN BE COMPARED WITH THE NUMBER OF IMPULSES PRODUCED BY THE SECOND TRANSDUCER DURING THE SAME AMOUNT OF MOVEMENT OF THE MOTOR.