Coulter Electronics, Inc.

Ian D Gilbert

Harvey J Dunstan

George G Dominick

Ervin Fayer

Ermi Roos

Michael T Halloran

Gerald J Dunstan

Avelino De Oliveira

A particle counter, of the type utilizing a Coulter(R) type aperature and a suction flow path downstream from the aperture, has a pair of electrodes on both sides of the aperture. A current is provided from the downstream electrode to the upstream electrode and pulses in the resulting voltage across the aperture are monitored to detect the passage of blood cells through the aperture. A grounded electrode is placed in the downstream flow path at a position near the package panel to isolate the cell counter from external electrical noise signals. An isolated high input inpedance amplifier is coupled to provide the monitored voltage to an inserted electrode positioned between the downstream aperture electrode and the grounded panel electrode. Because the inserted electrode and downstream electrode are then at the same voltage, no current flows through that portion of the flow path.

Isolation circuit for blood cell counter

A solenoid operated pinch valve including a housing and a hollow molded body coupled to said housing by a snap-on connection, a solenoid coil assembly seated within the housing, a plunger accommodated within said solenoid coil assembly for axial movement relative thereto controlled by energization of said solenoid coil assembly and between a pair of positions, said plunger having an end portion extending from the housing into said body and an opposite end portion received within said solenoid coil assembly, the body having a circumferential flange capable of being seated on one end of the housing and a pair of inflexible arms extending from the body in a coaxial direction relative thereto, said arms defining a passage for receiving a conduit across the path of movement of said plunger, a first orthogonal slot and a pair of resilient arms extending to the opposite end of the housing and engagable therewith in a snap-on coupling. One end of the plunger carries a second orthogonal slot. A flexible conduit having longitudinal ears unitary therewith is threadable thorugh the passage with the ears engaged within said orthogonal slots. A spring is provided for biasing the plunger against the flexible conduit to compress same closed, the solenoid coil assembly being energizable to move the plunger linearly against said bias by causing the plunger to pull the conduit open.

Snap-together solenoid operated pinch valve assembly

A centrifugal feeder includes a cylindrical feeder disc having an upwardly inclined uniform surface which is designed to expel particles placed thereon in a predetermined fashion by centrifugal force. The upwardly inclined surface of the disc may be designed to have a first predetermined expulsion rate which is the initial speed at which the disc must be rotated to expel any of the particles from the surface thereof. The disc also may be designed to have a final expulsion rate at which all particles placed on the surface thereof are expelled. The disc is rotated at a controlled rate of speed and at a controlled rate of change of speed to expel the particles in the manner desired in a linear or non linear fashion. The feed or expulsion rate of the particles is determined by the design of the disc and the rotation speed of the disc and essentially is independent of the size and density of the particles and the viscosity of the surrounding fluid in which the disc is rotated.

Centrifugal feeder

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St. Albans, United Kingdom

Ian D Gilbert