US1957482A - Electrolytic cell - Google Patents

Description

May 8, 1934. c. N. WINDECKER ET AL ELECTROLYTIC CELL Filed July 7, 1930 Patented May 8, 1934 UNITED STA ELECTROLYTIC can.

Clifton N. Windecker and Earl W. Tucker,

Painesville, Ohio, assignors to Diamond Alkali Company, Painesville, Ohio,

Delaware Application July'l, 1930, Serial Claims.

This invention relates to electrolytic cells, and has special reference to alkali-chlorine cells although some features of the invention are susceptible of use in other relations. The objects support can be transferred successively to different cathodes; the provision of a cathode which shall constitute an improved diaphragm support; the provision of a cell wherein the entire inclosed portion of the anode is submerged; the provision of improved expedients for preventing leakage or mixing of the evolved gases; while further objects and advantages of the invention will become apparent as the description proceeds.

In the drawing accompanying and forming a part of this application we have shown a preferred physical embodiment of our inventive idea although it will be understood that this showing is-intended to be merely illustrative of the principles of our invention and not limiting upon us either in respect of shape or proportion or design of parts, excepting as our claims shall specifically recite. Fig. 1 is a vertical sectional view through an alkali-chlorine cell containing our improvements; Fig. 2 is an enlarged sectional view showing a portion of the upper and lower-comers of said cell; Fig. 3 is a top plan view, and Fig. 4 is a horizontal sectional view on the line 4-4 of the cell shown in Fig. 1; Fig. 5 is a partial sectional view corresponding to the line 5-5 of Fig. 3; and Fig. 6 illustratesto enlarged scale a small portion of the cathode adjacent its upper edge.

The casing of our improved cell preferably exhibits a vertical fiat imperforate metal bottom 1 and a imperforate side-wall 2, the latter being preferably circular in cross-section although rectangular or prismatic shapes can be used, and wherever we have hereafter employed the word annular" we refer merely to the employment of a surrounded opening regardless of the shape of the opening or that of the surrounding part. Inside this side-wall near its upper edge we preferably locate an annular shelf or flange or ledge or bracket 3, which has the double advantage of stiffening the casing and of constituting a support for the anode and cover and limiting the po- TES PATENT OFFICE a corporation of sition of thesealing-provision or luting hereafter described.

Located inside the wall 2 is the cathode 4 which consists of a thin sheet-metal plate, annular in form and endless in horizontal section by reason of having its meeting edges welded or otherwise permanently secured together, and formed at its upper margin with an out-turned flange 5 and at its lower margin with an in-turned flange 6. The flange 5 is preferably seated on the support 3 at the same time that the flange 6 engages the bottom 1, although some tolerance in either direction is permissible. Th tween the two flanges e portion'of the sheet beis preferably completely covered with a very large number of closely crowded apertures '7, these being extended as near as expedient to the top flange and to the weld seam. These apertures are preferably long and narrow the better to support the diaphragm, which concathode and overlappin substance may here be sists of a layer 8 of suitable premeable material, applied smoothly all over .the inner face of the g flange 5. Any pervious used for this diaphragm which is not unduly attacked by the fluid with which it comes in contact and which has sufiicient strength to sustain the strain of bridging the comparatively small openings '7 against the pressure of the electrolyte. and very satisfactorily Asbestos paper is often used for the purpose, its

upper edge being molded out over the flange .5 as

shown at 8 in Fig. brought to the flange 6 2, and its lower edge being and its intermediate part being worked flat against the face of the sheet. This diaphragm is preferably molded and fon ned immediately against the surface of the cathode with which it is to be used, and thereafter requires no attention throughout its life.

The bottom of the cell is closed by means of a disk 10 of any suitable material such as cement of proper quality, resting on the flange 6 and sealed against any possibility of leakage by plastic material 11 around its periphery. The top of the cell is closed by means of a suitable cover,

also preferably made of cement, or the like molded, impervious, material, comprising a domeshaped portion lzsurrounded by a laterally-projecting flange 13 which rests on the upper flange of the cathode 5 over which the paper diaphragm is molded reinforced b space between the upper edge of the wall 2 y additional putty. The

periphery of this cover and the is filled with suitable putty or luting v14, so that this one joint makes a triple seal between the cell-w phragm, and the cover Formed in the flange all, the cathode, the dia- 13 are a plurality of apertures 15 arranged closely together around the entire circumference, and in each is located the reduced neck '16 of an anode 1'7. The body of each anode is preferably of rectangular shape 'as shown in Fig. 4, and is arranged tangent to the a circle which said anodes define. These anodes are secured in place in any suitable manner as by nuts 18 on the upper ends of the necks, suitable packing as indicated at 19 being employed to prevent leakage. 'These anodes are often made of graphite though I do not limit myself to any one material.

The dome 12 rises above the ends of the anodes and is provided with a gas-discharge pipe 20 and a liquid feed-pipe 21 tightly sealed therein. The pipe 20 is preferably connected to a suitable main 22 from which theescaping gas (e. g. chlorine in the case of an alkali-chlorine cell) is constantly pumped so as tomaintain at all times a predetermined pressure" which pressure is generally slightly below atmospheric. To the bottom of the side wall 2 is attached a liquid=discharge pipe 23 which enters the bottom of a sealing-cup 24, which overflows drop by drop into a funnel communicating with'the discharge conduit 25. A second gas-discharge pipe 26 (Fig. 5) connects the interior of the wall 2 to a second gas main 27; this being generally for hydrogen. Preferably the liquid inlet connection includes a drip jet 28 in a glass chamber 29. This type of inlet and outlet prevents the electrical connection of different cells through the electrolyte-liquid which is generally highly conductive. Suitable float valves are provided as indicated at 30 for maintaining a determined liquid level; which is preferably, according to our invention, maintained at some point within the dome 12 as indicated at 31, so as always to maintain the anodes completely submerged and thus cause themto waste away'at equalrate from bottom to top.

The anodes are suitably connected together by means of a metallic conducting element 32 from which leads the positive terminal 33, while the cathode 4 is provided with a terminal 34 which leads outwardly through a suitable pocket 35 formed in the side wall. V

The molding of the diaphragm on to the interior of an endless integral; unsevered cathode reduces to a minimum the danger of tears and breaks. Maintaining the liquid level within the domed top of the cover and hence above all seals precludes the possibility of gas-leaks, and hence of producing any explosive mixture which is one of the main elements of danger with such cells. Making the cathode without joints enables it to hold its shape better than heretofore and also enables the perforations to be placed unifcrmly over its surface, thus avoiding the presence of blank spaces which favor the occurrence of secondary reactions. This design of cathode and cover enables the clearance to be decreased thereby enabling a decrease both in the size of the hydrogen-space and of the distance between the electrodes. The decrease in internal resistance thus obtained, coupled with the use of a greater proportion of the length of the anodes, increases the output of each cell by a substantial percentage. As soon as the corrosion of the anodes has increased the electrode distance and hence the internal resistance of the cell by a determined amount the cover with all its electrodes are transferred to another cell of exactly the same type except that the cathode is of smaller diameter, thus enabling a further economical use of anodes which would otherwise have to be thrown away or used uneconomically. This is rendered possible by the uniform corrosion of the anodes and by the ease of making and'unmaking the triple seal 14.

It will be understood that some of the features of our improved cell can be employed without other features, or with modification of other features; and that we do not limit ourselves to any details herein described and illustrated except as specifically recited in our several claims which we desire may be construed broadly eachindependentlyfl of limitations contained in other claims.

Having thus described our invention what we claim is: j i

1. A cathode for an electrolytic cell comprising an upright endless, annular, metal member having closely located perforations, and having an outturned annular flange at its upper end and an.

inturned annular flange at its lower end,,in combination with a permeable diaphragm molded to the inner surface of said cathode and a disk located inside said annular member and resting on ;said internal flange and overlapping the lower end of said diaphragm, and lutingf'surrounding said :disk and sealing said disk and diaphragm and annular member together. 7

2. In an electrolytic cell, in combination, an annular casing, an annular, perforated, cathodeplate upright in said casing and having an inj turned flange at its lower end, said plate being circurinferentially endless, a permeable, diaphragm molded to the inner surface of said plate, and a bottom plate resting on said flange and overlapping said diaphragm, and lilting surrounding said bottom plate and sealing the same to said diaphragm and cathode plate."

3. An electrolytic ,cell comprising in combination an apertured cathode defining an electrolyte chamber, a permeable diaphragm covering; the inner surface of said cathode, cover means and bottom means cooperating with said cathode and diaphragm to form an enclosure, and a plurality of elongated, one-piece anode members having a relatively large portion within said electrolyte chamber, the entire such anode portion being of substantially uniform, generally rectangular cross section, extending along said cathode and being exposed to substantially uniform electrolytic action throughout its length and breadth, and the space between anodeand diaphragm being unobstructed whereby a cathode and diaphragm assembly of smaller size may be substituted for adjusting the spacing of anode and cathode to compensate for wearing away of the anode or anodes due to electrolysis.

' 4. In an electrolytic cell, in combination, an annular casing having an inwardly extending shoulder near its upper end but spaced therebelow, a perforated cathode having an outturned flange at its upper end overlying said shoulder, a diaphragm covering the inner surface of said cathode and having a portion overlying said flange, a cover means having its edge overlying said diaphragm portion, and externally accessible luting contacting said casing above said shoulder, said cover and said flange.

5. In an electrolytic cell, in combination, an annular casing having an inwardly extending shoulder near its upper end but spaced therebelow, a perforated cathode having an outturned flange at its upper end overlying said shoulder, a diaphragm covering the inner surface of said cathode and having a portion overlying said a ge, a cover means having its edge overlying said diaphragm portion, and externally accessible luting contacting said casing above said shoulder, said cover, said diaphragm portion and said flange.

6. A cathode for an electrolytic cell comprising a circumferentially endless, annular, perforated metal member haying an inturned annular flange at its lower end, a disk overlying said flange,- a permeable diaphragm covering the inner, active surface of said cathode and extending between the latter and said disk, and luting contacting said disk and said diaphragm to form a seal therebetween.

'7. A cathode for an electrolytic cell comprising a circumferentially endless, annular, perforated metal member having an inturned annular flange at its lower end, a disk overlying said flange, a permeable diaphragm covering the inner, active surface of said cathode and extending between the latter and said disk, and luting contacting said disk, said cathode flange and said diaphragm to form a seal therebetween.

8. An electrolytic cell comprising an outer receptacle, a ledge within the same adjacent to but spaced from the top thereof, a circumferentially endless cathode member having at its upper end an outturned flange overlying said ledge, a permeable diaphragm on the inner surface of said cathode and having its upper edge overlying said outturned flange, a domed cover member resting upon the outturned portion of said diaphragm and provided with a series of openings spaced a short distance from its edgegexteriorly accessible luting in the space between said cover member and outer receptacle and forming a seal between said members and said cathode, anode members sealed through said openings, and means for maintaining the liquid level in said cell above the top of the cathode and above that portion of the anode within the cell.

9. An electrolytic cell comprising an outer receptacle, a ledge within the same adjacent to but said members and said cathode, anode members sealed through said openings, and means for maintaining the liquid level in said cell above the top of the cathode and above that portion of the anode within the cell, the spaces between the anode and the diaphragm, from the lower surface of the cover member down, being entirely unobstructed.

10. An electrolytic cell comprising an outer receptacle, a ledge within the same, adjacent to but spaced from the top thereof, a circumferentially endless cathode member having at its upper end an outturned flange overlying said ledge, said ledge being so spacedfrom the bottom of said receptacle that said ledge and said bottom may jointly support said cathode, a permeable diaphragm on the inner surface of said cathode and having its upper edge overlying said outturned flange, a domed cover member resting upon the outturned portion of said diaphragm and provided with a series'of openings spaced a short distance from its edge, exteriorly accessible luting in the space between said cover member and outer receptacle and forming a seal between said members and said cathode, anode members sealed through said openings, and means for maintaining the liquid level in said cell above the top of the cathode and above that portion of the anode within the cell. 7

, CLIFTON N. WINDECKER.

EARL W. TUCKER.

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