Catalsimeter with time measuring circuitry for determining reactant concentration level

• US 4,015,121 A
• Filed: 07/15/1975
• Issued: 03/29/1977
• Est. Priority Date: 07/11/1974
• Status: Expired due to Term

• Current Assignee: Allca Instruments Company Limited
• Original Assignee: Allca Instruments Company Limited
• Inventors: Gagnon, Marcel, Baril, Michel, D'Aillon, Francois-Gros, Savoie, Claude
• Primary Examiner(s): Smith, Alfred E.
• Assistant Examiner(s): Moore, David K.
• Application Number:
  US05/596,166
• Time in Patent Office: 623 Days
• Field of Search: 195/103.5 R, 356/28, 250/574, 250/575, 250/576, 250/577, 250/221, 250/564-573, 324/175
• US Class Current: 250/221
• CPC Class Codes: G01N 31/00 Investigating or analysing non-biological materials by the use of the chemical methods specified in the subgroup; Apparatus specially adapted for such methods

Abstract

This invention relates to an apparatus and a method for determining the concentration of a first reactant in a medium. A disc is saturated with a solution containing the first reactant and immersed into a second reactant fluid. A chemical reaction occurs between the first and second reactants to produce a gas which is trapped by the disc. The disc is buoyed to the surface of the second reactant fluid by the gas produced. The process is electronically timed using photocells to start and stop an electronic clock and a digital display displays the time elapsed in tenths of seconds.

Claims

1. A circuit for electronically measuring and displaying a readout of elapsed time for a gas-trapping object saturated with a medium containing a first reactant to buoyantly rise within and break the surface of a fluid containing a second reactant at a predetermined concentration in a container due to the reaction of said first and second reactants to produce a gas following said gas-trapping object breaking said surface and sinking in the fluid, said circuit comprising:

a. photo-detector means for producing a start pulse when said gas-trapping object breaks said surface to sink in said fluid and a stop pulse when said gas-trapping object buoyantly rises and again breaks the surface of said fluid;

b. clock means for displaying said elapsed time between said start pulse and said stop pulse, said elapsed time being proportional to the concentration of said first reactant in said medium; and

c. means for electrically connecting said clock means and said photo-detector means, said electrically connecting means including means for passing said stop pulse only if said stop pulse should be produced after a predetermined time period following said production of said start pulse.

2. A circuit for electronically measuring and displaying a readout of elapsed time for a gas-trapping object saturated with a medium containing a first reactant to buoyantly rise within and break the plane of the surface of a fluid containing a second reactant at a predetermined concentration in a container due to the reaction of said first and second reactants to produce a gas following said gas-trapping object having broken said plane and sunken in the fluid, said circuit comprising:

a. photo-detector means for producing a start pulse when said gas-trapping object breaks said plane to sink in said fluid and a stop pulse when said gas-trapping object buoyantly rises and again breaks said plane of said fluid;

b. clock means for displaying said elapsed time between said start pulse and said stop pulse, said elapsed time being of at least a predetermined duration thereby to be proportional to the concentration of said first reactant in said medium; and

,

c. means for electrically connecting said clock means and said photo-detector means.

3. A circuit according to claim 2 wherein said photo-detector means includes at least one light source and photo-resistor, said light source and photo-resistor being paired and arranged on opposite sides of said container in a plane of the surface of said fluid.

4. A circuit according to claim 2 wherein said photo-detector means includes two light sources and photo-resistors, each said light source and photo-resistor being paired and arranged on opposite sides of said container in a plane of the surface of said fluid, said pairs being substantially orthogonally positioned with respect to one another.

5. A circuit according to claim 4 wherein said photo-detector means includes switch means, and said photo-resistors of said light source-photo-resistor pairs connected to said switch means, said switch means producing a pulse each time said gas-trapping object passes between at least one of said light source-photo-resistor pairs.

6. A circuit for electronically measuring and displaying a readout of elapsed time for a gas-trapping object saturated with a medium containing a first reactant to buoyantly rise within and break the surface of a fluid containing a second reactant at a predetermined concentration in a container due to the reaction of said first and second reactants to produce a gas following said gas-trapping object breaking said surface and sinking in the fluid, said circuit comprising:

a. photo-detector means for producing a start pulse when said gas-trapping object breaks said surface to sink in said fluid and a stop pulse when said gas-trapping object buoyantly rises and again breaks the surface of said fluid, said photo-detector means including

1. two light sources,

2. two photo-resistors, each said light source and photo-resistor being paired and arranged on opposite sides of said container in a plane of the surface of said fluid, said pairs being substantially orthogonally positioned with respect to one another, and

3. switch means, said photo-resistors of said light source-photo-resistor pairs connected to said switch means, said switch means producing a pulse each time said gas-trapping object passes between at least one of said light source-photo-resistor pairs;

b. clock means for displaying said elapsed time between said start pulse and said stop pulse, said elapsed time being proportional to the concentration of said first reactant in said medium; and

,

c. means for electrically connecting said clock means and said photo-detector means, said means including

1. pulse shaper means, said pulse shaper means producing a substantially square output pulse upon receipt of each said pulse from said switch means, and

2. means connecting said pulse shaper means and said switch means.

7. A circuit according to claim 6 wherein said electrical connecting means further includes control circuit means connected to said pulse shaper, said control circuit producing said start pulse upon receipt of said substantially square output pulse and thereafter said stop pulse if and only if said control circuit means receives said next substantially square output pulse a predetermined time period after receipt of the preceding substantially square output pulse.

8. A circuit according to claim 7 wherein said clock means includes clock pulse shaper means, said clock pulse shaper means connected to means providing a substantially sinusoidal 60 hertz output signal for producing substantially square clock pulses having a 60 cycle repetition rate.

9. A circuit according to claim 8 wherein said clock pulse shaper means is a Schmidt trigger.

10. A circuit according to claim 8 wherein said clock means further includes electronic counting means, said electronic counting means being connected to said control circuit means and to said clock pulse shaper means, said electronic counting means starting its count upon receipt of said start pulse, stopping its count upon receipt of said stop pulse and, while counting said clock pulses, producing a count output pulse upon counting each sixth clock pulse, thereby producing count output pulses at intervals of 0.1 seconds.

11. A circuit according to claim 10 wherein said clock means further includes display means, said display means connected to said electronic counting means for displaying the count of the number of said count output pulses.

12. A circuit according to claim 11 wherein said display means is a light emitting diode display.