Electrochemical sensor with temperature compensation means

• US 4,338,174 A
• Filed: 01/08/1979
• Issued: 07/06/1982
• Est. Priority Date: 01/08/1979
• Status: Expired due to Term

• Current Assignee: Critikon Co. LLC (GE Aerospace)
• Original Assignee: McNeilab, Inc. (Johnson & Johnson)
• Inventors: Tamura, Paul S.
• Primary Examiner(s): Kaplan, G. L.
• Application Number:
  US06/001,507
• Time in Patent Office: 1,275 Days
• Field of Search: 204/195 P, 204/195 B, 204/1 P, 128/2 E, 128/2.1 E, 324/29, 338/22 R, 338/22 SD
• US Class Current: 204/408
• CPC Class Codes: A61B 5/1491 Heated applicators
• CPC Class Codes: G01N 27/48 using polarography, i.e. measuring changes in current under a slowly-varying voltage
• CPC Class Codes: Y10S 604/901 Injection device with thermometer

Abstract

A disposable gas sensor, such as for monitoring pO₂ in blood or administered gases, includes a housing, a passageway therein for blood or gas, a membrane-anode-cathode polarographic assembly, and a temperature sensing element. The temperature sensing element penetrates the housing and includes a removable thermistor, which is matable with the housing for thermal contact with a metallic element, and which in turn is in direct contact with the fluid being monitored.

Claims

1. An electrochemical sensor comprising:

a housing defining a passageway for fluids to be monitored;

at least one electrode;

a membrane in said housing separating said electrode from fluid in said passageway;

and characterized by temperature sensing means, proximate said membrane, penetrating said housing and being in direct thermal contact with fluid in said passageway,

wherein said temperature sensing means comprises a removable collar carrying thermistor means, said collar being sealably matably received by said housing means to hold said thermistor means in direct thermal contact with said fluid, whereby said sensor is disposable but said temperature sensing means is reusable,

wherein said electrode includes a disposable portion carried by said housing and a reusable portion contactable with said disposable portion, wherein said housing includes an outwardly raised boss surrounding said disposable electrode portion, wherein said reusable electrode portion includes a collar for matable sealing engagement with said boss, and wherein said thermistor means collar includes a protuberance removably held between said boss and said electrode collar.

2. A sensor as described in claim 1 wherein said boss and said electrode collar are generally cylindrical, and wherein said protuberance includes an annular portion matable about said boss.

3. An electrochemical sensor comprising:

a housing defining a passageway for fluids to be monitored;

at least one electrode;

a membrane in said housing separating said electrode from fluid in said passageway;

and characterized by temperature sensing means, proximate said membrane, penetrating said housing and being in direct thermal contact with fluid in said passageway,

wherein said fluid is gas,

wherein said temperature sensing means includes a thermally conductive portion extending directly into said passageway in the gas flow, and thermistor means in thermal contact with said thermally conductive portion, and

wherein said thermistor means comprises a removable collar carrying a thermistor, said collar being sealably matably received by said housing means to hold said thermistor in contact with said thermally conductive portion, whereby said sensor, including said thermally conductive portion, is disposable but said thermistor means is reusable.

4. An electrochemical sensor comprising:

a housing defining a passageway for fluids to be monitored;

at least one electrode;

a membrane in said housing separating said electrode from fluid in said passageway;

and characterized by temperature sensing means, proximate said membrane, penetrating said housing and being in direct thermal contact with fluid in said passageway,

wherein said fluid is liquid,

wherein said temperature sensing means comprises a thermally conductive portion affixed to and generally conforming with the walls of said housing defining said passageway, and thermistor means in thermal contact with said thermally conductive portion, and

wherein said thermistor means comprises a removable collar carrying a thermistor, said collar being sealably matably received by said housing means to hold said thermistor in contact with said thermally conductive portion, whereby said sensor, including said thermally conductive portion, is disposable but said thermistor means is reusable.

5. An electrochemical sensor for monitoring partial pressure of select gases in a moving fluid comprising:

a housing defining a passageway through which fluids to be monitored are passed;

at least one electrode;

a membrane in said housing along the fluid flow path and separating said electrode from fluid in said passageway;

and temperature sensing means, proximate said membrane, penetrating said housing along the fluid flow path and being in direct thermal contact with fluid in said passageway, wherein said fluid is liquid and wherein said temperature sensing means comprises a thermally conductive portion affixed to and generally conforming with the walls of said housing defining said passageway, and thermistor means in thermal contact with said thermally conductive portion, wherein said fluid is blood, and wherein said passageway and said thermally conductive portion are mutually configured with minimum discontinuities thereby to prevent clotting in said passageway, wherein said thermally conductive portion includes a thermally conductive plate member imbedded in the walls of said housing slightly recessed from said passageway, wherein the edges of said passageway communicating with said plate member are rounded to prevent clotting of blood at the portion of the housing surrounding said plate member.