Patent ID: 6773561
Filing Date: 2004-08-10
Classification: C25B

Abstract:
In a unit cell for use in a bipolar, filter press type, aqueous alkali metal chloride solution electrolytic cell comprising a plurality of unit cells which are arranged in series through a cation exchange membrane disposed between respective adjacent unit cells, each unit cell comprising:an anode-side pan-shaped body having an anode compartment and an anode-side gas-liquid separation chamber which is disposed in an anode-side non-current flowing space left above said anode compartment and extends over the entire length of the upper side of said anode compartment, and a cathode-side pan-shaped body having a cathode compartment and a cathode-side gas-liquid separation chamber which is disposed in a cathode-side non-current flowing space left above said cathode compartment and extends over the entire length of the upper side of said cathode compartment, said anode-side pan-shaped body and said cathode-side pan-shaped body being disposed back to back, said anode-side and cathode-side gas-liquid separation chambers having perforated bottom walls separating said anode-side and cathode-side gas-liquid separation chambers from said anode compartment and said cathode compartment, respectively, and each of said gas-liquid separation chambers having, at one end thereof, a gas and liquid outlet nozzle, the improvement comprising a bubble removing partition wall which is disposed at least in said anode-side gas-liquid separation chamber of said anode-side and cathode-side gas-liquid separation chambers and which extends upwardly of the perforated bottom wall of the gas-liquid separation chamber, said bubble removing partition wall extending along the entire length of said gas-liquid separation chamber to partition said gas-liquid separation chamber into a first passage A formed on said bottom wall in a perforated area thereof and a second passage B formed on said bottom wall in a non-perforated area thereof, said bubble removing partition wall having an apertured segment having a plurality of apertures, wherein the aperture ratio of said apertured segment is in the range of from 30 to 70%, based on the area of the apertured segment, and the average area of the apertures of said apertured segment is in the range of from 3 to 60 mm2, the apertures of said apertured segment of the bubble removing partition wall being positioned at least 10 mm above the inside surface of the bottom wall of the gas-liquid separation chamber, wherein said second passage B communicates with said gas and liquid outlet nozzle and wherein said second passage B communicates with the anode compartment through said apertured segment and said first passage A.