Spa Water Sanitizing Method and Apparatus

Abstract

A spa sanitizing apparatus including a sanitizing agent generating cell, an H-Bridge circuit arranged to supply a voltage to electrodes of the cell, a controller circuit for controlling the operation of the H-Bridge circuit, and a watch dog circuit for monitoring a voltage applied to the electrodes and for shutting down power if the voltage departs from a pre-determined limit.

1 . Spa water sanitizing apparatus comprising:
 a sanitizing agent generating cell having first and second electrodes;   an H-Bridge circuit arranged to supply a voltage to the first and second electrodes of said generating cell;   a controller circuit configured to control the operation of said H-Bridge circuit;   a watch dog circuit configured to monitor a voltage applied to the first and second electrodes and for shutting down power to the H-Bridge circuit if said voltage departs from a pre-determined limit; and   wherein said controller circuit is configured to supply D.C. power of a first polarity to said generating cell for a first selected time interval, to turn off power to the cell for a second selected time interval, and to supply D.C. power of a polarity opposite to that of said first polarity to said cell for a third selected time interval.   
     
     
         2 . The apparatus of  claim 1  wherein said H-Bridge circuit comprises first, second, third and fourth power transistors and first and second bipolar transistors. 
     
     
         3 . The apparatus of  claim 2  wherein said controller circuit is connected to supply control signals to a base of each bipolar transistor and to a gate of each of the second and fourth of said power transistors. 
     
     
         4 . The apparatus of  claim 1  wherein said controller circuit comprises a programmed microprocessor. 
     
     
         5 . The apparatus of  claim 3  wherein said controller circuit comprises a programmed microprocessor. 
     
     
         6 . The apparatus of  claim 1  further including a relay connected to control the supply of power to the H-Bridge circuit and wherein the watchdog circuit is configured to cause the relay to turn off said power under one or more conditions. 
     
     
         7 . The apparatus of  claim 6  wherein the watchdog circuit is further configured to monitor first and second voltages applied to said cell. 
     
     
         8 . The apparatus of  claim 7  wherein said watchdog circuit is further configured to cause the relay to cut off power to the H-Bridge circuit if the first or second voltage is locked in an active mode for longer than a preset time. 
     
     
         9 . The apparatus of  claim 1  wherein the controller circuit is configured to monitor a current for a short circuit condition and to shut down the H-Bridge circuit if one occurs. 
     
     
         10 . The apparatus of  claim 1  wherein the controller circuit further determines a salt level concentration by comparing a sensed current to a calibration table. 
     
     
         11 . The apparatus of  claim 6  wherein the controller circuit is configured to monitor a current for a short circuit condition and to shut down the H-Bridge circuit if one occurs. 
     
     
         12 . The apparatus of  claim 11  wherein the controller circuit further determines a salt level concentration by comparing a sensed current to a calibration table. 
     
     
         13 . The apparatus of  claim 12  wherein said controller circuit comprises a programmed microprocessor. 
     
     
         14 . The apparatus of  claim 1  further including a diamond electrode disposed between the first and second electrodes of said sanitizing agent generating cell. 
     
     
         15 . Spa water sanitizing apparatus comprising:
 a sanitizing agent generating cell having first and second electrodes;   an H-Bridge circuit arranged to supply a voltage to the first and second electrodes of said generating cell;   a controller circuit configured to control the operation of said H-Bridge circuit, the controller circuit comprising one or more processors programmed to:
 (a) supply D.C. power of a first polarity to said generating cell for a first selected time interval after which power to the cell is turned off for a second selected time interval. 
 (b) monitor a current to detect a short circuit condition and to shut down the H-Bridge circuit if one occurs. 
 (c) determine a salt level concentration by comparing a sensed current to a calibration table. 
   
     
     
         16 . The apparatus of  claim 16  further comprising:
 a watch dog circuit configured to monitor a voltage applied to the first and second electrodes and for shutting down power to the H-Bridge circuit if said voltage departs from a pre-determined limit. 
 
     
     
         17 . The apparatus of  claim 16  further including a relay connected to control the supply of power to the H-Bridge circuit and wherein the watchdog circuit is configured to cause the relay to turn off said power under one or more conditions. 
     
     
         18 . The apparatus of  claim 17  wherein the watchdog circuit is further configured to monitor first and second voltages applied to said cell. 
     
     
         19 . The apparatus of  claim 18  wherein said watchdog circuit is further configured to cause the relay to cut off power to the H-Bridge circuit if the first or second voltage is locked in an active mode for longer than a preset time. 
     
     
         20 . The apparatus of  claim 15  wherein said one or more processors comprise a microcontroller. 
     
     
         21 . The apparatus of  claim 15  wherein said one or more processors comprise a microprocessor. 
     
     
         22 . A method of sanitizing water in a spa or tub comprising:
 providing a sanitizing agent generating cell positioned in the water of said spa or tub;   employing a voltage supply circuit to supply an operating voltage to said generating cell;   controlling the operation of said voltage supply circuit to cause it to supply D.C. power of a first polarity to said generating cell for a first selected time interval and turning power to the cell off for a second selected time interval;   monitoring a current to detect a short circuit condition and shutting down the voltage supply circuit if one occurs; and   determining a salt level concentration by comparing a sensed current to a calibration table.   
     
     
         23 . The method of  claim 22  further comprising monitoring a voltage applied to first and second electrodes of said cell and shutting down power to the voltage supply circuit if said voltage departs from a pre-determined limit. 
     
     
         24 . The method of  claim 23  further comprising employing a relay to control the supply of power to the voltage supply circuit and causing the relay to turn off said power under one or more conditions. 
     
     
         25 . The method of  claim 24  further comprising monitoring first and second voltages applied to said cell. 
     
     
         26 . The method of  claim 25  further comprising causing the relay to cut off power to the voltage supply circuit if the first or second voltage is locked in an active mode for longer than a preset time.