Method and apparatus for producing hydrogen peroxide

Abstract

An electrolytic cell includes an electrode in a chamber including an electrolyte and an electrical power supply arranged to supply electrical energy to the electrode. A current sensor detects electrical current in the cell. A reservoir of a metal salt solution is provided. A controller is arranged to supply metal salt solution from the reservoir to the chamber of the cell in dependence on the current detected at the sensor. This permits the conductivity of the electrolyte to be brought up to required levels quickly, independently of dynamic cell conditions. Previously, metal salt was added gradually to the electrolyte. This was time-consuming and produced inconsistent results.

1 . An apparatus for producing hydrogen peroxide, comprising:
 an electrolytic cell having an electrode in a chamber including an electrolyte,   an electrical power supply arranged to supply electrical energy to the electrode,   a current sensor arranged to detect electrical current in the cell,   a reservoir of a metal salt solution and   a controller arranged to supply metal salt solution to the chamber of the cell in dependence on the current detected at the sensor.   
     
     
         2 . The apparatus of  claim 1 , further comprising a pump arranged to circulate electrolyte between the chamber and a tank. 
     
     
         3 . The apparatus of  claim 2 , further comprising a mixer arranged to mix salt solution from the reservoir with the electrolyte from the tank prior to the electrolyte being pumped into the chamber. 
     
     
         4 . The apparatus of  claim 3 , further comprising a pump arranged to pump salt solution from the reservoir to the mixer. 
     
     
         5 . The apparatus of  claim 1 , in which the controller is arranged to compare the detected current with a predetermined current, and to supply a predetermined volume of the salt solution in dependence on the difference between the detected current and the predetermined current. 
     
     
         6 . The apparatus of  claim 1 , in which the current is detected by a current transducer. 
     
     
         7 . The apparatus of  claim 1 , in which the controller is arranged to record data relating to the change in conductivity of the cell according to the current detected at the sensor. 
     
     
         8 . The apparatus of  claim 1 , in which the electrolyte comprises a solution of a metal salt the same as that in the reservoir. 
     
     
         9 . The apparatus of  claim 8 , in which the metal salt is sodium chloride. 
     
     
         10 . The apparatus of  claim 1 , in which the electrode comprises a cathode in a cathode chamber. 
     
     
         11 . The apparatus of  claim 10 , in which the electrolytic cell further comprises an anode in a second chamber. 
     
     
         12 . The apparatus of  claim 11 , in which the second chamber includes a second electrolyte different from the electrolyte in the cathode chamber. 
     
     
         13 . (canceled) 
     
     
         14 . An appliance comprising the apparatus for producing hydrogen peroxide of  claim 1 . 
     
     
         15 . An automatic dishwasher comprising the apparatus for producing hydrogen peroxide of  claim 1 . 
     
     
         16 . A method of producing hydrogen peroxide, comprising:
 providing an electrolytic cell having an electrode in a chamber including an electrolyte,   activating an electrical power supply to supply electrical energy to the electrode,   detecting electrical current in the cell, and   supplying metal salt solution from a reservoir to the chamber of the cell in dependence on the current detected at the sensor so as to produce hydrogen peroxide.   
     
     
         17 . A method of washing dishes, comprising:
 providing an electrolytic cell having an electrode in a chamber including an electrolyte,   activating an electrical power supply to supply electrical energy to the electrode,   detecting electrical current in the cell, and   supplying metal salt solution from a reservoir to the chamber of the cell in dependence on the current detected at the sensor so as to produce hydrogen peroxide, and   applying the hydrogen peroxide to the dishes.