Electrolyzer and process

DETAILED DESCRIPTION What I claim is: 1.
The method for electrically connecting valve metal anode ribs and cathodically resistant metal cathode ribs through a bipolar plate comprised of a valve metal sheet on the anode side and steel plate on the cathode side of the bipolar plate, comprising inserting bimetal strips with a valve metal side and a side of a highly conductive metal resistant to hydrogen migration into grooves cut on the steel plate side opposite to the valve metal sheet, welding the valve metal sheet and the valve metal ribs to the valve metal side of the bimetal strips inserted into the grooves of the steel plate and electrically connecting the cathodically resistant metal cathode ribs to the highly conductive metal side of the bimetallic strips.
2.
The method of claim 1 wherein the grooves are trapezoidal.




Description:
STATE OF THE ART Chlorine and alkali metals hydroxides such as sodium hydroxide and potassium hydroxide are largely used commodities in every industrialized country and they are almost exclusively obtained by electrolysis of aqueous solutions of alkali metals chlorides, with a large share of the production coming from plants equipped with diaphragm or membrane cells.
With the advent of dimensionally stable materials of construction, the so called filter-press arrangement has become the most preferred one for diaphragm or membrane cells.
An electrolyzer of this type comprises a series of vertical bipolar elements comprising a bipolar separating wall carrying on one side thereof the cathode structure and on the other side the anode compartment with membranes or diaphragms positioned between the anode structure of one bipolar element and the cathode structure of the bipolar element adjacent in the series.
The electrolyzer also comprises an anode and cathode end plate at the two ends of the series connected to the respective poles of the current source.
The bipolar plate or wall performs multiple functions.
As a matter of fact, its acts as the end plate of the respective electrode compartment and electrically connects the cathode on one side of the bipolar element to the anode on the other side thereof and a frame, often integral with the bipolar wall, provides seal surfaces around the electrode compartments