Peristaltic pump with rotor position sensing employing a reflective object sensor

• US 5,711,654 A
• Filed: 06/07/1995
• Issued: 01/27/1998
• Est. Priority Date: 06/07/1995
• Status: Expired due to Fees

• Current Assignee: Baxter International Inc.
• Original Assignee: Baxter International Inc.
• Inventors: Afflerbaugh, Richard L.
• Primary Examiner(s): Thorpe, Timothy
• Assistant Examiner(s): Kim, Ted
• Application Number:
  US08/472,548
• Time in Patent Office: 965 Days
• Field of Search: 417/42, 417/63, 417/474-479
• US Class Current: 417/63
• CPC Class Codes: F04B 2201/1208 Angular position of the shaft
• CPC Class Codes: F04B 43/1253 by using two or more rollers as squeezing elements, the rollers moving on an arc of a circle during squeezing

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.

Claims

1. A peristaltic pumping mechanism comprising

a peristaltic pumping element including a pump rotor carrying a roller, a drive motor, a drive shaft coupling the drive motor to the pump rotor to rotate the pump rotor about a rotational axis in a range of rotational positions including a load position, in which the pump rotor is presented to receive pump tubing,

linkage coupled to the roller to move the roller between a retracted position free of contact with pump tubing and an extended position making operative contact with pump tubing,

a reflective object sensor that transmits energy along a first optical axis and senses reflected energy along a second optical axis, the first and second axes converging at an optical focus, the reflective object sensor generating an output that varies according to magnitude of the reflected energy,

a first disk carried by the drive shaft for rotation in synchrony with the pump rotor through the range of rotational positions, the first disk having an exterior surface made of a material that reflects energy transmitted by the reflective object sensor, the exterior surface being spaced in optical alignment with the reflective object sensor at or near the optical focus,

a second disk carried by the drive shaft concentrically about the first disk for common rotation in synchrony with the pump rotor, the second disk being spaced inside the optical focus of the reflective object sensor, the second disk covering the exterior surface of the first disk, except for a slotted region, through which the exterior surface of the first disk is exposed, the slotted region being in optical aligned with the reflective object sensor only when the pump rotor is in the load position,

the reflective object sensor generating, during rotation of the pump rotor through the range of rotational position, a first output while the slotted region is in optical alignment with the reflective object sensor and a second output different than the first output while the slotted region is out of optical alignment with the reflective object sensor, and

a controller coupled to the reflective object sensor, the drive motor, and the linkage operative in response to the first output to command the drive motor to cease rotation of the pump rotor and to command the linkage to move the roller to the retracted position.

2. A pumping mechanism according to claim 1 wherein the slotted region represents an arc of less than about 10°

of rotation of the pump rotor.

3. A pumping mechanism according to claim 1

wherein the peristaltic pumping element includes a pump race,

wherein the range of rotational positions includes a range of operating positions in which the roller is in operative alignment with the pump race, and

wherein, when the pump rotor is in the load position, the roller is out of operative alignment with the pump race.

4. A peristaltic pumping mechanism comprising

a peristaltic pumping element including a pump rotor carrying a roller, a drive motor, a drive shaft coupling the drive motor to the pump rotor to rotate the pump rotor about a rotational axis in a range of rotational positions, one of the positions comprising a load position in which the pump rotor is presented to receive pump tubing,

linkage coupled to the roller to move the roller between a retracted position free of contact with pump tubing and an extended position making operative contact with pump tubing,

a reflective object sensor that transmits energy along a first optical axis and senses reflected energy along a second optical axis, the first and second axes converging at an optical axis, the reflective object sensor generating an output that varies according to magnitude of the reflected energy,

a view disk carried by the drive shaft for rotation in synchrony with the pump rotor, the view disk having a first surface made of a material that reflects energy transmitted by the reflective object sensor and oriented in optical alignment with the reflective object sensor at or near the optical focus only when the pump rotor is in the load position, the view disk including a second surface oriented in optical alignment with the reflective object sensor when the pump rotor is outside the load position, the second surface being spaced from the optical focus,

the reflective object sensor generating, during rotation of the pump rotor, a first output while the first surface is in optical alignment with the reflective object sensor and a second output different than the first output while the first surface is out of optical alignment with the reflective object sensor, and

a controller coupled to the reflective object sensor, the drive motor, and the linkage operative in response to the first output to command the drive motor to cease rotation of the pump rotor and to command the linkage to move the roller to the retracted position.

5. A pumping mechanism according to claim 4 wherein the first surface represents an arc of less than about 10°

of rotation of the pump rotor.

6. A pumping mechanism according to claim 4

wherein the peristaltic pumping element includes a pump race,

wherein the range of rotational positions includes a range of operating positions in which the roller is in operative alignment with the pump race, and

wherein, when the pump rotor is in the load position, the roller is out of operative alignment with the pump race.