FLUID ANALYZING APPARATUS

• US 3,658,478 A
• Filed: 04/07/1970
• Issued: 04/25/1972
• Est. Priority Date: 04/07/1970
• Status: Expired due to Term

• Current Assignee: Fisher Scientific Co. (Thermo Fisher Scientific Incorporated)
• Original Assignee: David E. Blackmer, Philip Spergel, Ronald Mcfayden, Stanley L. Gaines, Thomas A. Rosse, William Maxwell
• Inventors: Spergel, Philip, Gaines, Stanley L., Blackmer, David E., Maxwell, William, McFayden, Ronald, Rosse, Thomas A.
• Primary Examiner(s): Scovronek, Joseph
• Application Number:
  US05/027,200
• Time in Patent Office: 749 Days
• Field of Search: 23/253,23B,259,254E,255E 204/195T,195P 324/29,30
• US Class Current: 422/81
• CPC Class Codes: B01L 7/00 Heating or cooling apparatus autoclaves B01J3/04; Heat insulating devices
• CPC Class Codes: G01N 35/00 Automatic analysis not limited to methods or materials provided for in any single one of groups G01N1/00 - G01N33/00; Handling materials therefor

Abstract

A fluid sample analysis instrument includes two sample chambers with an electrode assembly associated with each sample chamber. The instrument includes a common pump system for applying reduced pressure to the sample chambers to produce flow of fluid into and out of the sample chambers and a common circulator system for circulating fluid past the electrode assemblies and sample chambers to maintain the sample chambers and electrode assemblies at a pre-established temperature.

Claims

2. The instrument as claimed in claim 1 wherein one electrode assembly associated with a first sample chamber produces an output signal as a function of the pH of the sample in its sample chamber and the electrode assembly associated with a second sample chamber produces an output signal as a function of the partial pressure of a predetermined gas in the sample in its sample chamber.

3. The instrument as claimed in claim 2 wherein the electrode assembly associated with said second sample chamber includes a selectively permeable membrane disposed for exposure to the sample in said second sample chamber and output circuitry for producing an output signal as a function of a gas of interest permeating through said membrane.

4. A blood gas analysis instrument comprising a sample chamber, a plurality of electrode assemblies for sensing gaseous constituents of a sample held in said sample chamber, each said electrode assembly including a selectively permeable membrane disposed for exposure to the sample in said sample chamber and output circuitry for producing an output signal as a function of a gas of interest permeating through the membrane of the electrode assembly, two sources of calibrating fluids, a first valve connected to said two sources of calibrating fluids for selectively applying one of said calibrating fluids to an outlet line, a source of cleaning fluid, a relatively low capacity pump, a higher capacity pump, a second valve connected to the inlet to said sample chamber for controlling flow of fluid to said sample chamber, said second valve having a first position for connecting a sampling passage to said sample chamber, a second position for connecting said outlet line to said sample chamber, and a third position for connecting a source of cleaning fluid to said sample chamber, a third valve connected to the outlet of said sample chamber, said third valve having a first position for connecting the sample chamber to said relatively low capacity pump, a second position for connecting said sample chamber to said higher capacity pump, a third position for connecting said sample chamber to the atmosphere, and a fourth position for blocking the outlet of said sample chamber, a manually operable pump connected to said sample chamber for displacing fluid in said sample chamber, a circulator for circulating a thermostatically controlled fluid past said electrode assemblies and said sample chamber to maintain the sample chamber and electrode assemblies at a pre-established temperature, a fourth valve connected between one of said sources of calibrating fluid and said source of cleaning fluid for introducing calibrating gas into said cleaning fluid to reduce shock to the membranes of said electrode assemblies during exposure to said cleaning fluid in a flushing operation, and a sequencer for controlling the operation of said second and third valves, said sequencer having a first mode of operation in response to a first request for operating said second valve to connect said sample chamber to said cleaning fluid while said third valve is connected to said higher capacity pump;

a second mode of operation in response to a second request for positioning said second valve to sequentially connect said sample chamber to said sample line, said cleaning fluid and a calibrating gas while said third valve is connected to said higher capacity pump and then switching said third valve to said fourth position; and

a third mode of operation in response to a third request for positioning said second valve to connect said sample chamber to said sample line while said third valve is connected to said low capacity pump and then switching said third valve to said fourth position for a sample measuring interval.

5. The instrument as claimed in claim 4 wherein said sequencer includes control logic for providing visual indication of the operating mode of the instrument and means to modify said visual indication during said sample measuring interval.

6. The instrument as claimed in claim 5 wherein said control logic includes a status circuit having outputs indicating the operating mode of said instrument, and first bistable means responsive to the end of said sample measuring interval for changing the output of said status circuit.

7. The instrument as claimed in claim 6 wherein said control logic further includes logic for optionally deferring initiation of said calibration sequence for an interval of time to extend the duration of said sample measuring interval, said calibration sequence deferring logic including second bistable means responsive to an extend request for inhibiting the operation of said first bistate means to the end of said sample measuring interval.

8. The instrument as claimed in claim 7 and further including a second sample chamber having an inlet and an outlet, a second electrode assembly associated with said second sample chamber for sensing a constituent of a sample held in said second sample chamber, said electrode assembly producing an output signal as a function of a constituent of interest of the sample in said second chamber, a common pump system for applying reduced pressure to both sample chambers to produce flow of fluid into and out of said sample chambers and a common circulator system for circulating said thermostatically controlled fluid past said electrode assemblies and said sample chambers to maintain the sample chambers and electrode assemblies at a preestablished temperature.

9. The instrument as claimed in claim 8 wherein said sequencer in said first mode of operation sequentially operates said second valve to connect said sample chamber to said cleaning fluid while said third valve is connected to said high capacity pump, and then switches said third valve to said fourth position and closes said fourth valve.