Abstract: The position of a rotating pump element is sensed by a reflective object sensor 406 in association with a view disk 412 coupled to the operative element for rotation in synchrony with the operative element. The view disk 412 has first 422 and second 420 surface portions that present themselves in succession to the reflective object sensor during rotation of the operative element. The first surface portion 422 is spaced at or near the optical focus of the reflective object sensor, whereas the second surface portion 422 is not. The reflective object sensor 406 thus generates different outputs, depending upon whether the first surface or second surface portions are in optical alignment with the reflective object sensor.

Abstract: A peristaltic pumping apparatus includes a pump rotor carrying a roller and a drive mechanism for rotating the rotor. The drive mechanism includes a carrier for holding the pump rotor. The apparatus includes a release pin mechanism carried on the pump rotor and exposed to access by a user. The release pin mechanism is movable by the user between a first position that connects the pump rotor to the carrier and a second position that disconnects the pump rotor from the carrier. Placing the release pin mechanism in the second position allows quick separation of the pump rotor from the drive mechanism.

Abstract: A self-loading peristaltic pumping apparatus includes a pump race for receiving a tubing loop, a pump rotor carrying a roller, and a drive mechanism for rotating the rotor within the pump race. The apparatus also includes a roller locating mechanism that moves the pump roller between a retracted position, free of contact with the received tubing loop, and an extended position, at least partially within the pump race for operative contact with the received tubing loop. The apparatus includes at least one tubing guide element carried by the rotor. The guide element extends from the rotor at least partially into the pump race. The guide element serves during rotation of the rotor with the roller in its retracted position, for contacting the received tubing loop to orient the tubing loop within the pump race.

Abstract: There is disclosed herein a dialysis machine for use with a negative-pressure-type dialyzer. The machine includes a flow system for drawing fresh dialysis solution, under a negative pressure, through the dialyzer and a system for determining, setting and controlling ultrafiltration rates in the dialyzer. The ultrafiltration system includes a branch for communication with the dialyzer when flow to and from the dialyzer is terminated. In the branch there is provided a pump for applying negative pressure to the dialyzer and drawing liquid therethrough, and a meter for measuring the flow rates. Means are also provided for measuring negative pressure and transmembrane pressure during operation of the ultrafiltration branch. Pressure controls are also provided so as to assure maintenance of the ultrafiltration rates.There is also disclosed herein a method for determining, setting and controlling the ultrafiltration rate.