US1349597A - Electrolytic cell - Google Patents

Description

H. l. ALLEN AND K. H. FOX.

ELECTROLYIIC CELL. APPLICAHON FILED APRL2. 19m.

Patented Aug. 17, 1920.

A I" .Il

4M Q ,f 7 m. l. /H w, a i. n wm H.1.ALLEN AND K. R. EUX.

ELECTRGLYTLC CELL. APPUCAUOM man APR.2.`19\9.

Patented A110'. 17, 1920.

1 a l J u wm u l 1 z z f l l LVIhILLsLML1- H. l. ALLEN AND K. R. FOX.

ELECTROLYTIC CELL.

APPucArloN mw APR.2,19|9.

1,349,597. Patented Aug. 17, 1926.

3 SHEETS-SHEE] 3.

UNITED STATES PATENT OFFICE.

HERBERT I. ALLEN AND KENT B. FOX, OF PORTLAND, MAINE, ASSIGNORS TO ELECTRON CHEMICAL COMPANY, OF PORTLAND, MAINE, A

OF MAINE.

CORPORATION ELECTROLYTIC CELL.

Specioation of Letters Patent.

Patented Aug. 17, 1920.

Application filed April 2, 1919. Serial No. 286,950.

This invention has for its object to provide an electrolytic cell ofgsimple construction, in which the cathode and anode are so constructed and arranged as to afford a maximum conducting surface for the palsage of the current through the electrolyte, and ,in which certain other advantages will be obtained as hereinafter made plain.

In the embodiment of the invention selected for illustration and description, the tank is oblong in plan view. Resting thereon is the free-board section in which the chlorin is collected, and in which there may be a columnof the electrolyte to increase the hydrostatic head. To-the under side of the free-board section is attached the cathode which lis in the shape of a rectangular box or basket approximating the shape of but smaller than the tank, and whichV is suspended from the free-board section into the tank. By removing the free-board section, theicathode and the anode may be removed bodily therewith from the tank. The boxlike cathode is made of sheet iron and its sides, ends and bottoms are provided With numerous perforations for te passage of the solution of brine and caustic and of the hydrogen. Within the cathode is an anode with side, end and bottom faces confrontlng the corresponding parts of the cathode and Referring now to the accompanying draw.

figure 1 represents, in vertical longitudinal section, an electrolytic cell embodyingr our invention. Y

Fig. 2 represents a plan view thereof.

Fig. 3 represents a horizontal section through the cell.

Fig. 4 represents n tion through the cell.

Fig. 5 shows the cathode detached.

Fig. 6 shows a section on a larger scale, through one of the boltsl by Which the cathode is attached to the upper free-board sectransverse vertical section of the cell, and shows how the cathode and the margin of the diaphragm are clamped thereto to make a Water-tight and gas-tight joint.

Fig. 7 is a section of the cathode on a 60 large scale, showing how the diaphragm is arranged to cover the slde and bottom walls thereof.

The cell, as shown, comprises the tank which is preferably made of iron or steel'65 sheets or plates, and which as stated is oblongr in plan view. lt has the bottom 10 with an upturned marginal flange 11 to which are riveted the plates or sheets (one or more) which are ends 12 and sides 13. From the bottom of the. body leads a pipe 14 for conducting away the products of the electrolytic decomposition of the electrolyte.

The free-board section of the cell is preferably made of slabs of slate, cast concrete or other inert material, of the proper dimensions, which are secured together in any convenient way to constitute the end Walls 15 and Side Walls 16, flush with the corresponding walls 12 and"13 of the tank. The upper end of the free-board section is closed by a cover consisting of a slab or plate 17 of similar material inert to chlorin. This cover is provided with holes to receive the feeding 35 tube 18, and the nipple 19 with which the conduit 20`is connected for conducting away the chlorin.

The cathode 21, as has been described, consists of a sheet metal box or basket (preferably iron) havingr a bottom Q2, sides 23 and ends 24, and it is of such dimensions as to fit within the tank and be spaced from the walls and bottom thereof, as shown in Fig.

l. All of the walls of the cathode are provided with numerous closely spaced perforations,preferably small slots in herringbone. formation. At their' upper edges. the end and side Walls of the cathode are provided with out-turned marginal [langes 25. rentrant angles 2G at the corners of the box are filled with square plates 27, Whose upper surfaces are located above those of the flanges a distance about equal to the thickness of the diaphragm when the latter is under compression. The purpose of the flange will be subsequently explained; and it will suffice here to state that it is preferably in Width substantially equal to the widths of the side and end walls of the freebent to constitute the 70 The 100 hoard section of the cell. The cathode tapers downwardly as indicated in Figs. l and 4.

'itbin the cathode is arranged a diaphragm to cover the side, end and bottom walls thereof. lreferably the diaphragm consists of one or more layers or strips of porousI asbestos pa per 2H laid lengthwise on the bottom of the cathode, uml then bent upwardly so as to cover the end walls thereof as shown in Fig. l, with its extremities bent outwardly to overlap the end liauges. The inner faces of the side walls of the cathode are likewise covered by sheets 2l) of asbestos which terminate at and cover the bottom of the cathode (so as to furnish a double layer thereon) and which have their upper extremities overlapping on the side fiangcs 25. 'l'he reiintrant angles, forlned by the sheets at the corners, are filled by the plates or blocks 2T. A rectangular frame ISU of iron (either a casting or four bars suitably connected) is employed to clamp the flange of the cathode and the diaphragm to the under side. of the free-board sec-tion of the cell. Bolts 3l are passed through apertures in cover and in the sides and ends ot' the freeboard section and are secured into the rec tangular frame, and on the ends which project upon the cover are nuts 32, by tightening which the frame, the cathode, the margins of the diaphragm, the free-board section and the cover may all he clamped rigidly together. The frame merely rests upon the upper edges of the walls of the tank, so that it and the parts connected thereto may be removed as a unit from said tank. The flanges :$5 are imperforate, and the margins of the diaphragm between them and the wallsl l5, 1G, serve as packing and make a gas and liquid-tight joint to prevent the escape of liquor or gas. lf desired, the margins may be impregnated with an insulatingr material inert to chlorin. W'ithin the cathode and the diaphragm there is located the anode which consists of the. elongated carbon or 4h'heson graphite plates 33whieh are shown as eight in number, with a set of four plates closely confronting each side wall of the cathode and spaced from the other set. These. plates are secured by earbon or graphite pins 3,4 to the upright` carbon bars or rods 35 which Space the sets apart and which project upwardly from and through the cover 1i". Said rods have connected to their exposed endsa bus bar 36 to which the positive lead \\'ires of the circuit are connected. The anode may be hung from the cover, but preferably it rests upon transverse supports 37 of insnlatingvmaterial such as glass., porcelain or other inert substance placed upon the bottom offthe cathode. At the ends ofthe two sets o'l' carbon plates or slabs 2&3, there are blocks or bars Srl of carbon or graphite, whiin are flush with the en'd faces of said plates or slabs 33, so as to forni end faces or conducting surfaces coufrontilu,r the surfaces or faces of the. end walls of the cathode. The anode is thus in the shape, roughly, of an oblong rectangular tube which `is open at theitop and bottom to permit the circulation of the electrolyte downwardly therethrough and upwardl .through the spaces between the sides and ein s of the anode and the cathode. 'lhe bottom surfaces or faces of theanode` confront the active bottom wall ofthe cathode, so that (except for the space between the two sets of anode plates) there is a maximum conducting surface. for the passage of the currcnt through the electrolvte to the cathode. At one end of the cathode, the flange 2] is bent upwardly to provide a plate or extension 40 to lie outside of and parallel with thi.l freedioard section of the cell as shown in Figs. l and 5. rl`o tliis plate is secured a bus bar -ll with which the negative lead wire of the circuit is secured.

lt will bc understood` of course, that anv suitable. inert cement or other packing mahterial is used to close any spaces between the walls of thc apertures of the cover and the members which pass thereinto, such as the feed well 18, the anode bars 35, and the gas nipple 1S), to prevent the escape of free ohlorin into the` atmosphere.

In practice, the sodium chlonid solution is fed continuouslyY into the feedwell (which has an ednction port or aperture 43 at its lower submerged end) from the usual float valve. the level of the electrolyte heilig maintained preferably below the top of the cathode and above the tops of the anode plates. The electrolyte pereolates through the porous diaphragm into contact with the perforated side, end and bottom walls of the cathode. The caustic soda resulting from the reaction, together with the undecomposed brine, flows or drops into the bottom of the tank, and is colltinuouslv conducted away therefrom through the discharge or eduction pipe 14 for concentration and eva poration of the caustic solution and removal of the salt therein contained. liberated on the surfaces of the anode is collected in the free-lmard section of the cell and conducted away through the nipple 19 and the conduit 2u.

The. faces of the anode are close to the confronting faces of the cathode. the spaee between them decreasing in width downwardly to compensate for the resistance of the. anodes.

lt is of course evident that` although we have described the cell as used for the elec` trolysis of an aqueous sodium chlorid Solur tion. it may be en'iploved for the electrolytic dcconiposition of other suitable chemical compounds.

From thc foregoing description which we The chlorin have given of the cell, it will be apparent to those who are skilled in the art that there are certain advantages resulting therefrom. It may be noted, for instance, that practically the entire inner face of the cathode, including the bottom, sides and end walls, is electrically active, and that the exterior faces ofthe cathode are wholly nnsubmerged in any body of electrolyte, the eduction pipe serving to insure the removal from the tank of the eiliuent from the cell. The fianges of the cathode are solid and not perforated, but the perforations in the side and end walls terminate at the corners formed by the lianges and said walls, so that every )art of the cathode which is in contact witli the electrolyte is perforated so as to permit the, free flow of the electrolyte and the emission of the hydrogen which is liberated at the inner faces of the cathode outside of the diaphragm. By providing a water-tight and gas-tight pressure joint between the cathode and the free-board section, it is possible to build up the column of electrolyte in said free-board section so as to secure thc desired hydrostatic head as the diaphragm becomes more or less clogged with the impurities in the l 'ine, thus insuringr a longer diaphragm life than would otherwise be possible. The hydrogen, which collects in the tank. escapes through whatever crevices there may be between the top edges of the walls thereof and the rectangular frame which rests thereon. but, if desired, of course, the tank ma)r be provided with a pipe outlet for conducting away and utilizing the hydrogen, in which case of course a suitable packing material may be interposed between the rectangular frame and the top of the tank.

T he bottom of the cathode is preferably provided with at least two layers of the asbcstos sheets constituting the diaphragm so that the tiow through the diaphragm and cathode will be equaliacd by checking the How through the bottom. The presence of the tank is of course desirable to prevent thc admission of air to the hydrogen-containing space exterior of the cathode and to prevent the formation of carbonates.

Theoretically the best results are secured only when there are maximum surfaces of cathode and anode in provimit)7 with the electrolyte between them so that all part-s ot' the cathode and anode arc. electrically active, for, where portions of the cathode or cell body are inactive, deterioration soon sets in and the efficiency of the cell is lowcrcd. There is another consideration, however. to wit, that in order to prevent wastage of the current. there shall be a constant supply of saturated brine. ln the cell, which we have herein described, it will be apparent that we not only provide for the free, How of brine to the active surfaces of cathode.

the anode and cathode, but that this is accomplished without diminishing to any material extent Vthe active surface of the To allow for the free passage of the electrolyte from one portion of the anode chamber to another, the anode is, as previously stated, submerged slightly at least in the electrolyte, and at the bottom of the anode there is an open space through which the electrolyte may pass. lf desired, of course., the anode plates may be thicker so as to decrease the opening or passageway therethrough, and thus increase the active anode surface. lVe have found that the relative proportions, as illustrated in the drawings, are desirable in that they provide for the presence of a relatively large body of electrolyte to prevent its tot rapid impoverishrnent of salt, which of course would impair the efficiency' of the cell.

le should not regard it as a departure from the spirit and scope of the invention if the tank were filled with oil or other liquid ilnmiscible with the caustic eflluent, and by reference to the cathode being exteriorly unsubmerged we have in mind a construction in which the exterior faces (side, bottom and the end Walls) of the cathode are not in contact with an accumulation of the cell etliuent.

Having thus explained the nature of our said invention and described a way of making and using the same, although without attempting to set forth all of the forms in which it may bc made or all of the modes of its use, what we claim is:-

1. An electrolytic cell comprising a suit- I able tank, a rectangular box-shaped cathode having perforated active end, side and bottom walls, a diaphragm covering the inner faces of all of said walls, anda rectangular tubular anode of similar cross section disposed within the cathode, supported on the bottom thereof, and havingV end. side and bottom faces confronting and spaced from the like active faces of the cathode.

An electrolytio cell comprising a` su`table tank, a rectangular box-shaped cathode having active end, side and bottom walls all provided with perforations, a diaphragm covering all the inner faces of thc cathode walls, a rectangular tubular anode disposed within the cathode and having active faces confronting and spaced from the active sidc, bottom `and end walls of the cathode.

3. An electrolytic cell comprising a rectangular tank. a removable rectangular f reeboard or top section resting thereon, a bo like cathode clamped to and suspended from said free-board section and having perforated side, end and bottom walls. a diaphragm covering the inner faces of said walls and clamped between the cathode and said free-board section, and an anode arranged within said cathode and having active side, end and bottom faces confronting and spaced from the inner faces of the corresponding walls of said cathode.

4. An elcctrolytic cell comprising a suitable tank with means for discharging the cilluent therefrom to prevent the accumulation oi' the ctllnent. a tubular cathode and a tubular anode therein, said tubular cathode having active bottom and side walls which are externally unsubmerged and are spaced from said tank and also from said anode.

An electrolytic cell comprising a tubular open-end anode, the sheet metal tubular cathode ninclosing and underlying the anode, and having its sides and bottom perforated and exteriorly unsubmerged, a diaphrafm covering ,the inner faces of the sides and bottom of the cathode, and a tank in which said cathode is suspended with the sides and bottom spaced from the walls of said tank.

(i. An electrolftic cell comprising a tubular open-end anode, a tubular cathode int-[osing and underlying the anode, and-having its sides and bottom perforated and extcriorly unsubmerged, a diaphragm covering the inner faces of the sides and bottom of the cathode, in combination with a tank a free-board section resting thereon, and nic-ans for connecting the cathode and freeboard section bya liquid-tight joint, whereby said cathode is suspended from the freeboard section in the tank with the Walls of the cathode spaced from the walls of the tank.

7. An elcctrolytic cell comprising a tank a free-board section removably supported upon the upper ed e of the tank, a cathode foi-ined as a metal asket having perforated side, bottom and end walls, and having outturncd marginal flanges at its upper end, a porous diaphragm covering all the active faces of the cathode and having marginal edges out-turned over said marginal flanges, clamp bars secured to said free-board section to clamp the out-turned edges of the diaphragm and the out-turned flanges of the cathode to the free-board section to form a substantially gas-tight joint and enable the cathode to be suspended from the freeboard section into the tank, and an anode within the cathode and having active faces confronting and spaced from the active fares thereof.

S. An f-lcctrolytic cell comprising a tank, a cathodiformed as a metal basket suspended within said tank and having perforated bottom, side and end walls spaced fron. the walls of said tank. an anode occupying the interior of said cathode and supporird on thi` bottom thereof, and insulating nrc-.ins interposed between said anode and the porterait-d metallic bottoni Wall of said lia-'liet` cell compri-ing a cathode formed as a rectangular basket with perforated end, bottom and side walls, a diaphragm covering the inner faces of said walls, a free-board section from which said basket is suspended, a tank on the upper end of which said free-board section rests with the walls of the cathode spaced from the walls of the tank, and a tubular anode occnpyln the space in said cathode with active si e, bottom and end faces confronting but spaced from the corresponding active Walls of said cathode.

10. An electrolytic cell comprising a cathode formed as a rectangular basket with perforated end, bottom and side walls, a d1aphragm covering the inner faces of said Walls, a free-board section from which said basket is suspended, a tank on the upper end of which said free-board section rests with the walls of the cathode spaced from the walls of the tank, a tubular anode occuying the space in said cathode with its side,

ottom and end faces confronting but spaced from the corresponding Walls of said cathode, and insulators resting on the bottom wall of the cathode for supporting said anode.

11. In an electrolytic cell, in combination, a cathode formed as a rectangular metal basket with erforated end and side walls, a porous diap ragm covering the inner faces of said Walls, and an anode occupying the space within the cathode and comprising spaced longitudinal side bars and end bars occupying the spaces between and secured to the ends of said longitudinal bars, all to form active faces confronting and spaced from the active faces of the perforated side and end walls of the cathode.

12. An electro] tic cell comprising a cathode consisting ofy a sheet-metal rectangular basket having perforated active side, end and bottom. walls, a rectangular tubular anode having spaced longitudinal side bars and end bars between and secured to the ends of said side bars, all spaced from the end, bottom and side walls of the cathode, said side and end bars being below the top of the cathode, insulators resting on the bottom of the cathode for supporting the anode, and rods between and secured to said anode-side-bars for conducting the electric current thereto.

13. An electrolytic cell comprising a cathode consisting of a sheet-metal rectangular basket having perforated active side, end and bottom walls, a tubular anode having spaced longitudinal side bars and end bars 'between and secured to the ends of said side bars, all spaced from the end, bottom and side walls of the cathode, said side and end ybars being below the top of the cathode, in-

sulators resting on the bottom of the cathode for supporting the anode, rods Vbetween and secured to said anode-side-bars for conducting the electric current thereto, and an extension from one of the Walls of said cathode for conducting the current therefrom.

1l. In an electrolytic cell, in combination` a cathode formed as a rectangular metal basket with perforated end and side Walls, a porous diaphragm covering the inner faces of said walls, an anode occupying the space within the cathode and comprising spaced longitudinal side bars and end bars occupying the spaces between and secured to the ends of said longitudinal bars, all to form active faces confronting and spaced from the active faces of the perforated side and end walls of the cathode, a tank provided with draining means to prevent the accumulation of effluent therein, a free-board section adapted to rest upon the tank, and meansl for clam ing said cathode to the under side of said free-hoard section to suspend it therefrom, with the bottom, side and end walls of the cathode spaced from the walls of said tank, whereby said cathode is exteriorly unsubmerged.

l5. An electrolytic cell comprising an upper closed free-board section, a metallic basket-like cathode attached to and suspended therefrom by a substantially liquidtight joint and having perforated side, bottom and end Walls furnishing active faces, a porous diaphragm covering the inner faces of the cathode, a tubularanode occupying the space Within the cathode and spaced from the inner faces of the end, bottom and side walls thereof with its upper edges free to permit the electrolyte to flow thereover, a tank on Which the free-board section rests with the cathode suspended therein and spaced from the Walls thereof, and means for withdrawing the effluent from said tank' to prevent the submergence of the cathode therein, said parts being so arranged that the level of the electrolyte in the free-board Section may be abovel the top of the tank to increase the hydrostatic pressure.

In testimony whereof we have affixed our signatures.

HERBERT I. ALLEN. KENT R. FOX.

Images