Apparatus and method for control and sterilization of fluid flow

• US 4,728,496 A
• Filed: 05/29/1986
• Issued: 03/01/1988
• Est. Priority Date: 06/04/1985
• Status: Expired due to Term

• Current Assignee: Gambro Lundia AB (Baxter International Inc.)
• Original Assignee: Gambro AB (Baxter International Inc.)
• Inventors: Petersen, Preben A., Sternby, Jan P.
• Primary Examiner(s): Richman, Barry S.
• Assistant Examiner(s): Johnson, William R.
• Application Number:
  US06/868,353
• Time in Patent Office: 642 Days
• Field of Search: 422/1, 137/340, 210/321.2, 210/321.3
• US Class Current: 422/1
• CPC Class Codes: A61M 1/1686 by heat
• CPC Class Codes: A61M 1/1688 with recirculation of the sterilising fluid
• CPC Class Codes: Y10T 137/6579 Circulating fluid in heat exchange relationship

Abstract

Apparatus and methods for controlling and sterilizing the flow of fluids through a medical treatment device such as a dialyzer including a fluid flow inlet for feeding the fluid to the medical treatment device, a heater for controlling the supply of heat to the fluid in the fluid flow inlet, a fluid flow outlet for withdrawing contaminated fluid from the dialyzer, a recirculation duct for recirculating at least a portion of the heated fluid from a point in the fluid flow inlet to an upstream point in the fluid flow inlet in which the heated fluid can again pass through the heater, and valves for selectively directing at least a portion of the fluid to the recirculation duct for sterilization purposes. The method further includes flowing the fluid through a fluid flow inlet, supplying heat to the fluid in the fluid flow inlet, feeding the heated fluid to the dialyzer, withdrawing contaminated fluid from the dialyzer, and intermittently recirculating at least a portion of the heated fluid from a point upstream of the dialyzer to a point in the fluid flow inlet whereby the recirculated heated fluid can again pass through the heater so that the fluid flow inlet can be sterilized thereby.

Claims

1. A method for controlling the flow of a fluid through a medical treatment device which subjects said fluid to contamination and in which said fluid is normally maintained at a predetermined treatment temperature, said method comprising flowing said fluid through a fluid flow inlet path, controllably supplying heat to said fluid at a predetermined heating location in said fluid flow inlet path, feeding said heated fluid to said medical treatment device, withdrawing said contaminated fluid from said medical treatment device, and intermittently recirculating at least a portion of said heated fluid from a point upstream of said medical treatment device to a point in said fluid flow inlet path upstream of said predetermined heating location so that said at least a portion of said heated fluid again passes through said predetermined heating location whereby said fluid flow inlet path may be disinfected or sterilized by recirculating said fluid through said predetermined heating location so as to raise the temperature of said fluid to a temperature above said predetermined heating temperature while said intermittent recirculation does not take place from a point downstream of said medical treatment device where said contaminated fluid normally flows.

2. The method of claim 1 wherein said controllably supplying heat to said fluid at said predetermined heating location is sufficient to raise the temperature of said fluid to an elevated temperature of about 90°

C. whereby during said sterilizing said temperature of said at least a portion of said fluid is also heated to a temperature of about 90°

C. while the temperature of said fluid downstream of said predetermined heating location drops to a temperature of about 80°

C.

3. The method of claim 1 including maintaining the pressure in said predetermined fluid flow path substantially constant.

4. The method of claim 3 wherein said substantially constant pressure comprises atmospheric pressure.

5. The method of claim 1 wherein said intermittently recirculated portion of heated fluid comprises the major portion of said heated fluid, whereby only a minor portion of said heated fluid is withdrawn from said medical treatment device.

6. The method of claim 5 wherein said minor portion of said heated fluid comprises about one-fifth of the total volume of said heated fluid.

7. Apparatus for controlling the flow of a fluid through a medical treatment device which subjects said fluid to contamination and in which said fluid is normally maintained at a predetermined treatment temperature, said apparatus comprising a fluid flow inlet path for feeding said fluid to said medical treatment device, temperature control means including heating means for controlling the supply of heat to said fluid at a predetermined heating location in said fluid flow inlet path, a fluid flow outlet path for withdrawing said contaminated fluid from said medical treatment device, recirculation means for recirculation of at least a portion of said heated fluid from a point in said fluid flow inlet path upstream of said medical treatment device to a point further upstream in said fluid flow inlet path which is upstream of said predetermined heating location whereby said heated fluid again passes through said predetermined heating location, and selective actuation means for selective actuation of said recirculation means when it is desired to sterilize said apparatus, whereby said apparatus can be disinfected or sterilized by recirculating said fluid through said temperature control means so as to raise the temperature of said fluid to a temperature above said predetermined treatment temperature and selectively actuating said selective actuation means whereby said at least a portion of said fluid is recirculated through said recirculation means while at the same time said recirculation does not take place from a point downstream of said medical treatment device where said contaminated fluid normally flows.

8. The apparatus of claim 7 wherein said temperature control means is adapted to raise the temperature of said fluid to an elevated temperature of about 90°

C., whereby during sterilization the temperature of said at least a portion of said fluid recirculated in said recirculation means is also heated to a temperature of about 90°

C. while the temperature of said fluid downstream of said temperature control means drops to a temperature of about 80°

C.

9. The apparatus of claim 7 wherein said medical treatment device comprises a dialyzer whereby said contamination of said fluid comprises the production of a dialysate therein.