Small portable electrolytic sodium hypochlorite on site generators

Abstract

The present invention describes four preferred embodiments of an apparatus aimed to the production of a dilute solution of sodium hypochlorite. It uses the process of the electrolysis of a dilute solution of sodium chloride in water by means of two metallic electrodes immersed in the solution. The electricity needed may be delivered by a range of sources like disposable cells (alkaline), rechargeable batteries, photovoltaic modules (PVM) or electromechanical generators, like alternators or dynamos, moved by human power. All the apparatus described operate in batch mode. They are small lightweight portable units, easily transportable anywhere, in remote areas or emergency situations where chemicals or electricity is not available. Main use is the purification of drinking water, but also the production of sterilizing solutions for wound disinfection, washing etc.

1 . Portable apparatus for the production of Sodium Hypochlorite by means of the electrolysis of a dilute solution of Sodium Chloride in water, comprising a container in which is enclosed an electrolytic cell which is composed by a vessel equipped with at least two electrodes made of metal like titanium or titanium coated with noble metals like ruthenium, tantalum, lanthanum oxides, suited to contain a predetermined quantity of diluted sodium chloride solution, an autonomous source of electric energy and a circuit for connecting said source of electric energy to the electrodes of the aforesaid electrolytic cell. 
     
     
         2 . Portable apparatus as claimed in  claim 1  wherein said connecting circuit comprises means for interrupting the operation of said electrolytic cell after a time delay in relation to the current intensity and time supplied to the electrodes of said electrolytic cell, and to the concentration of the solution introduced into said electrolytic cell. 
     
     
         3 . Portable apparatus as claimed in  claim 1  and  2  wherein said connecting circuit comprises means for stabilizing the current and/or the voltage delivered by said autonomous source of electric energy to said electrodes of the electrolytic cell. 
     
     
         4 . Portable apparatus as claimed in any one of the preceding claims wherein said means for interrupting the operation of the electrolytic cell comprises an integrator circuit of the current delivered, in relation to time, to said electrodes of the electrolytic cell, the output of said integrator being connected to a comparator circuit that compares the value of the current integral provided by said integrator circuit with a predetermined reference value, said comparator being connected to a switch in order to interrupt the current supplied to the electrolytic cell when said current integral has reached a predetermined value. 
     
     
         5 . Portable apparatus as claimed in any one of the preceding claims comprising a circuit which interrupts the electric energy supply to said electrolytic cell in case of absence of Sodium Chloride solution in said electrolytic cell. 
     
     
         6 . Portable apparatus as claimed in any one of the preceding claims wherein said circuit comprises a comparator circuit whose input is connected to the electrodes of said electrolytic cell, and whose output is connected to said switch. 
     
     
         7 . Portable apparatus as claimed in any one of the preceding claims wherein said switch consists of a mechanical relay. 
     
     
         8 . Portable apparatus as claimed in any one of the preceding claims wherein said switch consists of a solid state relay. 
     
     
         9 . Portable apparatus as claimed in any one of the preceding claims wherein said electrical energy in the form of voltage or current delivered by the emf source is detected by a threshold circuit of the Schmitt trigger type. 
     
     
         10 . Portable apparatus as claimed in any one of the preceding claims wherein said means for voltage stabilization includes a dc (direct current) voltage stabilizer. 
     
     
         11 . Portable apparatus as claimed in any one of the preceding claims wherein said means for current stabilization includes a dc constant current stabilizer. 
     
     
         12 . Portable apparatus as claimed in any one of the preceding claims wherein said means for voltage stabilization includes a converter from ac (alternate current) current to dc current. 
     
     
         13 . Portable apparatus as claimed in any one of the preceding claims wherein said power supply circuit includes a pushbutton switch to turn on said portable apparatus, said pushbutton switch being connected in series with aforesaid switch. 
     
     
         14 . Portable apparatus as claimed in any one of the preceding claims wherein said threshold circuit when it senses a preset value of the constant current delivered to said electrodes of the electrolytic cell, a pulse generator is activated and connected to a counter which is set to a specific preset count. When the counter stops a shut-off pulse is sent to the said constant current stabilizer shutting off the current to said electrodes of said electrolytic cell. 
     
     
         15 . Portable apparatus as claimed in any one of the preceding claims wherein said pulse generator is connected between said constant current stabilizer and said counter. 
     
     
         16 . Portable apparatus as claimed in any one of the preceding claims wherein said counter is set to a number of counts which determine the quantity of electric energy delivered to the electrodes of said electrolytic cell. 
     
     
         17 . Portable apparatus as claimed in any one of the preceding claims wherein said electrolytic cell comprises a vessel suited to contain a predetermined quantity of Sodium Chloride diluted solution, said vessel being fitted with said electrodes and being closed with a removable cover. 
     
     
         18 . Portable apparatus as claimed in any one of the preceding claims wherein said vessel is made of transparent material bearing a reference notch to indicate the level of the solution when poured into said electrolytic cell. 
     
     
         19 . Portable apparatus as claimed in any one of the preceding claims wherein said cover has a cavity suitable for dosage of the Sodium Chloride to be introduced into said electrolytic cell in order to prepare the diluted Sodium Chloride solution. 
     
     
         20 . Portable apparatus as claimed in any one of the preceding claims wherein said cover has a cylindrical form with an eccentric hole. Said cover is free to rotate in a cylindrical housing having on its bottom a hole of the same diameter of the hole in said rotating cover, the two holes being coincident for a specific position of said rotating cover. 
     
     
         21 . Portable apparatus as claimed in any one of the preceding claims wherein said electrodes of the electrolytic cell have a rectangular shape, having a surface area comprised between 1 and 15 square centimeters and being placed parallel to each other with a gap comprised between 1 and 5 mm. 
     
     
         22 . Portable apparatus as claimed in any one of the preceding claims wherein said anode and said cathode are made of Titanium coated with noble metal oxides like ruthenium, tantalum, titanium, lanthanum, etc., said coating being proprietary. 
     
     
         23 . Portable apparatus as claimed in any one of the preceding claims wherein said connecting circuit is fitted into a sealed compartment (hereinafter called first compartment) separated from said electrolytic cell and from another compartment (hereinafter called second compartment) containing said autonomous electric energy source. 
     
     
         24 . Portable apparatus as claimed in any one of the preceding claims wherein said part of said container, called first compartment, is permanently connected to the part of said container, called second compartment, being provided means for an electrical connection between said connecting circuit, fitted in the first compartment, and said electric energy source fitted in said second compartment. 
     
     
         25 . Portable apparatus as claimed in any one of the preceding claims wherein said connecting circuit is provided with a cable for the connection to an external source of electric energy. 
     
     
         26 . Portable apparatus as claimed in any one of the preceding claims wherein said autonomous electric energy source comprises at least one electric cell (disposable type). 
     
     
         27 . Portable apparatus as claimed in any one of the preceding claims wherein said autonomous electric energy source comprises at least one rechargeable battery. 
     
     
         28 . Portable apparatus as claimed in any one of the preceding claims wherein said autonomous electric energy source comprises at least one supercapacitor. 
     
     
         29 . Portable apparatus as claimed in any one of the preceding claims wherein said autonomous electric energy source comprises an alternator or dynamo. 
     
     
         30 . Portable apparatus as claimed in any one of the preceding claims comprising means for hand driving of said alternator or dynamo. 
     
     
         31 . Portable apparatus as claimed in any one of the preceding claims wherein said autonomous electric energy source comprises a photovoltaic module (PVM). 
     
     
         32 . Portable apparatus for the production of Sodium Hypochlorite by means of the electrolysis of a diluted solution of Sodium Chloride comprising any one of the characteristics as herein described with reference to and as shown in the accompanying drawings.