Expandable anodes for chlor-alkali diaphragm cells

Abstract

An adjustable elastic element ( 19 ) for forcing the surfaces of expandable-type anodes for diaphragm chlor-alkali cells wherein such element consists of a U-shaped elastic sheet provided with at least one adjusting mechanism comprising both one collar ( 29 ) which fastens the elastic sheet through openings obtained in the sheet itself and one gear ( 23 ) connectable to a removable external tool consisting of a handle and a shaft whereby turning the tool, a rotation of the gears is produced, in its turn acting on the collar controlling the span of the anode surfaces. And the span is freely adjustable in order to establish a predetermined controlled gap between anode and finger-supported diaphragm surfaces, or alternatively to bring such surfaces in contact without introducing however a useless and hazardous compression.

1 . An expandable-type anode for diaphragm chlor-alkali electrolysis cells comprising a conductive stem, two movable surfaces optionally provided with an electrocatalytic film for chlorine evolution connected to said conductive stem through connecting sheets and at least one forcing elastic element directed to adjust the gap between said movable surfaces and the diaphragm surface, said at least one forcing elastic element being provided with edges having an adjustable span, said span being adjustable by means of an extractable tool.  
   
   
       2 . The anode of  claim 1  wherein said adjustable span of said edges is externally adjustable.  
   
   
       3 . The anode of  claim 1  wherein said extractable tool is made of quenched and tempered low-alloy steel.  
   
   
       4 . The anode of  claim 1  wherein said edges of said at least one forcing elastic element are provided with fins engaging said connecting sheets.  
   
   
       5 . The anode of  claim 1  further comprising constraint elements suitable to hold said movable surfaces in a restrained position during the assemblage in said cells.  
   
   
       6 . The anode of  claim 5  wherein said constraint elements are extractable.  
   
   
       7 . The anode of  claim 1  wherein said at least one forcing elastic element comprises an elastic sheet with U-shaped profile provided with at least one adjusting mechanism.  
   
   
       8 . The anode of  claim 7  wherein said at least one forcing elastic element and said at least one adjusting mechanism are made of titanium or titanium alloys.  
   
   
       9 . The anode of  claim 7  wherein said at least one adjusting mechanism comprises a collar fastening the at least one forcing elastic element through openings made in said element and wherein said at least one adjusting mechanism can be operated by means of at least one gear.  
   
   
       10 . The anode of  claim 9  wherein said at least one gear is rotated by means of an extractable external adjusting tool comprising a shaft provided with a handle, said shaft being connectable to said at least one gear.  
   
   
       11 . The anode of  claim 10  wherein said shaft is made with a high torque resistance material.  
   
   
       12 . The anode of  claim 7  wherein said at least one forcing elastic element comprises at least two of said adjusting mechanisms respectively positioned in the upper and in the lower part of said element.  
   
   
       13 . The anode of  claim 7  wherein said at least one adjusting mechanism comprises at least one treated shaft connectable to a crank driven by a tool comprising a lever.  
   
   
       14 . The anode of  claim 13  wherein said at least one adjusting mechanism comprises pair of threaded shafts.  
   
   
       15 . The anode of  claim 13  wherein said at least one forcing elastic element comprises at least two of said adjusting mechanisms respectively positioned in the upper and in the lower part of said element.  
   
   
       16 . The anode of  claim 1  being an operated anode of the prior art modified by means of adequate processing.  
   
   
       17 . The anode of  claim 16  wherein said adequate processing comprises the elimination of original constraint elements suitable to hold said movable surfaces in a restrained position.  
   
   
       18 . A diaphragm chlor-alkali electrolysis cell comprising at least one anode of  claim 1 .  
   
   
       19 . A diaphragm chlor-alkali electrolysis process carried out with at least one cell of  claim 18  wherein the gap between said movable surfaces of said at least one anode and the corresponding diaphragm surface is externally regulated through said span of said edges of said forcing elastic element before said at least one cell is put in operation.  
   
   
       20 . The process of  claim 19  wherein said gap is adjusted so as to bring the movable surfaces of said at least one anode in contact with corresponding diaphragm surface while preventing the application of harmful pressures.  
   
   
       21 . The process of  claim 19  wherein said gap is adjusted to a finished predetermined extent.  
   
   
       22 . Expandable-type anode for diaphragm chlor-alkali electrolysis cells substantially as herein described with reference to the attached drawings.