Abstract: A liquid sampling, metering and transfer valve assembly for providing plural dilutions of a single liquid sample comprising a pair of outer stationary elements sandwiching a rotatable element, the rotatable element carrying precise volume segmenting passageways, the outer elements carrying counterpart passageways for communicating to the exterior of the valve assembly, one outer element carrying loops each for storing a precise volume of diluent and the other valve elements carrying through passageways for communicating to and from said respective loops. A continuous body of sample is introduced into the valve assembly along a path through a pair of the segmenting passageays and a pair of aliquot portions isolated from said parth. The rotatable element is operated to direct one aliquot along with the content of one loop to an exterior location for mixing. The other sample aliquot is retained.

Abstract: 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.

Abstract: Bellows pump and actuating apparatus for automatically aspirating biological sample fluid material into and through an aspirating probe from a source of fluid sample material, into and through a sample segmenting valve for passage through a counting device. A plurality of bellows members, each having an axis of compression and expansion, has one end mounted on a fixed member. Timing and stroke members are provided for actuating movement of the other end of the bellows members, which are free to be moved parallel to their axis. A positioning member positions the timing and stroke members coaxially of the bellows members at preselected times. A drive member moves the timing and stroke members parallel to the axis of compression and expansion of the bellows members. Photo-optical indicating members, cooperating with the positioning member, interrupts the drive to the positioning member when the timing and stroke members are coaxially aligned with the bellows members.

Abstract: Disclosed is an improved centrifuge apparatus for separating substances of varying density and a method of controlling the speed of a rotor of the centrifuge apparatus. A vent-view port is mounted for in-out adjustment within an access aperture formed in a lid of the centrifuge apparatus so as to provide for selective opening of vent holes formed in the vent-view port. In addition to venting, the vent-view port has a sensor mount with a transparent window for receiving a tachometer probe for rotor speed monitoring. Additionally, a desired centrifugal force and a desired accumulative centrifugal force can be entered by a human operator. A control unit adjusts the rotor speed and operational cycle time to meet the inputted desired force values while displaying the actual accumulative centrifugal force at the end of the operation cycle.