Water quality monitor for a water purification system

• US 5,145,575 A
• Filed: 10/02/1991
• Issued: 09/08/1992
• Est. Priority Date: 03/09/1990
• Status: Expired due to Term

• Current Assignee: Culligan International Company
• Original Assignee: Bruce D. Burrows
• Inventors: Burrows, Bruce D.
• Primary Examiner(s): Dawson, Robert A.
• Assistant Examiner(s): DRODGE, JOSEPH W
• Application Number:
  US07/770,663
• Time in Patent Office: 342 Days
• Field of Search: 210/85, 210/86, 210/96.1, 210/96.2, 210/746, 324/426, 324/439, 324/441-446, 340/603, 340/657, 340/659, 340/815.01, 340/815.1
• US Class Current: 210/85
• CPC Class Codes: B01D 61/12 Controlling or regulating
• CPC Class Codes: C02F 1/441 by reverse osmosis
• CPC Class Codes: C02F 2209/05 Conductivity or salinity
• CPC Class Codes: G01N 27/06 of a liquid involving electrolysis G01N27/26
• CPC Class Codes: G01N 33/18 Water

Abstract

A water quality monitor is provided for use in a purified water supply system of the type having a reverse osmosis unit for producing relatively purified water from an ordinary tap water supply. The monitor includes a control circuit having electrodes in contact with the purified and tap water supplies. The control circuit is activated by depression of a test button, preferably in response to opening of a faucet valve to dispense water, to produce a short duration pulse of one polarity which is connected to the electrodes for use in determining the water conductivities. The control circuit compares the conductivities of the purified and tap water supplies, and maintains an appropriate indicator light in an illuminated state until the test button is released, at which time the control circuit couples a short duration pulse of opposite polarity to the electrodes for minimizing electrode corrosion and/or accumulation of ionic deposits. The generation of a short duration pulse to determine conductivity, in combination with illumination of the appropriate indicator light only until the test button is released, minimizes circuit power consumption and thereby extends service life when a battery power source is used.

Claims

1. A water quality monitor adapted for use in a water purification system adapted to produce a relatively purified water supply from a tap water supply, said water quality monitor comprising:

electrode means for contacting the tap water supply and the relatively purified water supply produced from the tap water supply by a purification system and obtaining respective conductivities of said supplies;

circuit means having a switch movable between first and second positions and including means activated upon movement of said switch to said first position for generating a short duration pulse of one polarity and for connecting said pulse to said electrode means, said circuit means further including means for determining relative ratios of the conductivities of the tap and purified water supplies and for comparing said ratios with a selected threshold representing satisfactory operating performance of the purification system and for generating one of first and second outputs respectively representing satisfactory and unsatisfactory system performance;

indicator means responsive to said one of said first and second outputs to indicate system performance;

said circuit means further including means for maintaining said indicator means in an operative state to indicate system performance while said switch is in said first position, and for a duration independent of and potentially longer than the duration of said pulse; and

faucet valve means for dispensing purified water from the purification system, said faucet valve means including means for moving said switch between said first and second positions.

2. The water quality monitor of claim 1 wherein said indicator means comprises a pair of indicator lights.

3. The water quality monitor of claim 1 wherein said indicator means comprises a pair of indicator lights of different colors.

4. The water quality monitor of claim 1 wherein said electrode means comprises first and second electrode pairs respectively contacting the tap water supply and the purified water supply.

5. The water quality monitor of claim 4 wherein said first and second electrode pairs are connected in series.

6. The water quality monitor of claim 1 wherein said circuit means further includes reset means for resetting said circuit means upon movement of said switch to said first position.

7. The water quality monitor of claim 6 wherein said circuit means further includes time delay means for disabling said reset means for a predetermined minimum time delay period following movement of said switch to said second position.

8. A water quality monitor adapted for use in a water purification system adapted to produce a relatively purified water supply from a tap water supply, said water quality monitor co

electrode means for contacting the relatively purified water supply produced from the tap water supply by the purification system and obtaining the conductivity of said purified water supply;

circuit means a switch movable between first and second positions and including means activated upon movement of said switch to said first position for generating a short duration pulse and for delivering said pulse to said electrode means, said circuit means further including means for determining the conductivity of the purified water supply in comparison with a selected threshold representing satisfactory operating performance of the purification system and for generating one of first and second outputs respectively representing satisfactory and unsatisfactory system performance;

indicating means responsive to said one of said first and second outputs to indicate system performance;

said circuit means further including means for maintaining said indicator means in an operative state to indicate system performance while said switch is in said first position, and for a duration independent of and potentially longer than the duration of said pulse; and

faucet valve means for dispensing purified water from the purification system, said faucet valve means including means for moving said switch between said first and second positions.

9. The water quality monitor of claim 8 wherein said indicator means comprises a pair of indicator lights of different colors.

10. The water quality monitor of claim 8 wherein said short duration pulse has a first polarity, said circuit means further including means for generating and connecting a short duration pulse of a second, opposite polarity to said electrode means upon movement of said switch to said second position.

11. A water quality monitor adapted for use in a water purification system adapted to produce a relatively purified water supply from a tap water supply, said water quality monitor comprising:

a first electrode probe contacting the tap water supply, said first probe including a pair of electrodes in predetermined spaced relation;

a second electrode probe contacting the relatively purified water supply produced from the tap water supply by the purification system, said second probe including a pair of electrodes in predetermined spaced relation;

test switch means movable between first and second positions;

circuit means responsive to movement of said test switch means to said first position to generate a short duration pulse of one polarity and to deliver said pulse in series to said first and second probes;

said circuit means further including comparator means for comparing the voltage at a junction between said first and second probes with a selected threshold voltage representative of acceptable operating performance of the purification system, and for generating one of first and second outputs in response thereto wherein said first and second outputs respectively represent satisfactory and unsatisfactory system performance;

first and second indicator means, said circuit means further including latch means responsive to said one of said first and second outputs for activating said first indicator means when system performance is satisfactory and for activating said second indicator means when system performance is unsatisfactory, said latch means maintaining the appropriate one of the first and second indicator means in an activated state to indicate system performance while said switch means is in said first position, for a duration independent of the duration of and potentially longer than said pulse of one polarity, said circuit means further including means for generating and connecting a short duration pulse of opposite polarity to said first and second probes upon movement of said switch means to said second position; and

faucet valve means for dispensing purified water from the purification system, said faucet valve means including means for moving said switch means between said first and second positions.

12. A water quality monitor adapted for use in a water purification system adapted to produce a relatively purified water supply from a tap water supply, said water quality monitor comprising:

electrode means for contacting the relatively purified water supply produced from the tap supply by the purification system and obtaining the conductivity of said purified water supply;

circuit means connected to said electrode means and including test switch means movable between first and second positions, said circuit means including means for delivering a short duration pulse to said electrode means upon movement of said test switch means to said first position, and for generating an output signal representative of the conductivity of the purified water supply;

indicator means responsive to said output signal to indicate the conductivity of the purified water supply for a duration independent of and potentially longer, than the duration of said pulse, said circuit means including means for maintaining said indicator means in a state indicating said conductivity until said test switch means is moved from said position to said second position; and

faucet valve means for dispensing purified water from the purification system, said faucet valve means including means for moving said switch means between said first and second positions.

13. The water quality monitor of claim 12 wherein said short duration pulse has a first polarity, said circuit means further including means for generating and connecting a short duration pulse of a second opposite polarity to said electrode means upon movement of said switch to said second position.

14. A water quality monitor adapted for use in a water purification system adapted to produce a relatively purified water supply from a tap water supply, said water quality monitor comprising:

electrode means for contacting the tap water supply and the relatively purified water supply produced from the tap water supply by the purification system and obtaining respective conductivities of said supplies;

circuit means having a switch movable between first and second positions and including means activated upon movement of said switch to said first position for generating a short duration pulse of one polarity and for connecting said pulse to said electrode means, said circuit means further including means for determining relative ratios of the conductivities of the tap and purified water supplies and for comparing said ratios with a selected threshold representing satisfactory operating performance of the purification system and for generating one of first and second outputs respectively representing satisfactory and unsatisfactory system performance; and

indicator means responsive to said one of said first and second outputs to indicate system performance;

said circuit means further including means for maintaining said indicator means in an operative state for a duration independent of and potentially longer than the duration of said pulse.

15. The water quality monitor of claim 14 wherein said indicator means comprises a pair of indicator lights.

16. The water quality monitor of claim 14 wherein said electrode means comprises first and second electrode pairs respectively contacting the tap water supply and the purified water supply.

17. The water quality monitor of claim 16 wherein said first and second electrode pairs are connected in series.

18. A water quality monitor adapted for use in a water purification system adapted to produce a relatively purified water supply from a tap water supply, said water quality monitor comprising:

electrode means for contacting the relatively purified water supply produced from the tap water supply by the purification system and obtaining the conductivity of said purified water supply;

circuit means having a switch movable between first and second positions and including means activated upon movement of said switch to said first position for generating a short duration pulse and for delivering said pulse to said electrode means, said circuit means further including means for determining the conductivity of the purified water supply in comparison with a selected threshold representing satisfactory operating performance of the purification system and for generating one of first and second outputs respectively representing satisfactory and unsatisfactory system performance; and

indicating means responsive to said one of said first and second outputs to indicate system performance;

said circuit means further including means for maintaining said indicator means in an operative state for a duration independent of and potentially longer than the duration of said pulse.

19. A water quality monitor adapted for use in a water purification system adapted to produce a relatively purified water supply from a tap water supply, said water quality monitor comprising:

electrode means for contacting the relatively purified water supply produced from the tap supply by the purification system and obtaining the conductivity of said purified water supply;

circuit means connected to said electrode means and including test switch means movable between first and second positions, said circuit means including means for delivering a short duration pulse to said electrode means upon movement of said test switch means to said first position, and for generating an output signal representative of the conductivity of the purified water supply; and

indicator means responsive to said output signal to indicate the conductivity of the purified water supply for a duration independent of and potentially longer, than the duration of said pulse.