US2011171A - Electrolyzing apparatus - Google Patents

Description

J. c.- BAKER- ELECTROLYZING APPARATUS Aug. 13, 1935.

Filed April 10, 1931 2 Sheets-Sheet l I 2 Q 3141104 001 I 46:- flum 1 Aug. 13, 1935. v J. c. BAKER I 2,011,171

' ELEGTROLYZ ING APPARATUS Filed April 10, 1951 2 Sheets-Sheet 2 Patented Aug. 13, 1935 UNITED STATES PATENT OFFICE ELECTROLYZIN G APPARATUS John C. Baker, Montclair, N. J., assignor to Wallace & Tiernan Products, Inc., Belleville, 'N. J a corporation of New Jersey Application April 10, 1931, Serial No. 9,019

17 Claims. (01. 204-58) This invention relates generally to electrolytic A feature common to all of the cells illustrated cells, and has particular reference to cells for is that they all have what is essentially a horiproducing chlorine by an electrolytic process. i zontal cathode and a horizontal anode forming- One object of the invention is to provide an walls of the electrolyzing cell. The anode is the electrolytic cell which will require little attention upper one of the pair and the chlorine is formed 5 over a relatively long period of time. or liberated on its face.

Another object is to provide a cell of the kind The anode and the cathode are separated by an indicated in which the internal resistance is subannular insulating spacer, which may be relastantially constant and uniform over the entire tively narrow, and forms a wall around the elec-" area of the electrodes. trolyzing chamber between the electrodes. In 10- Another object is to provide a construction in addition to spacing the electrodes apart sufwhich the flow of brine may be varied according ficiently to give room between them for a supply to requirements. This is accomplished by varyof electrolyte, the spacer should also be wide ing the height of the liquid in the brine supply enough to allow room for the gas generated to if) and with respect to the anode and cathode betravel over the face of the electrode to a point of 5 tween which the electrolysis occurs. escape and to allow for an accumulation of sludge Other objects are to provide a construction in from the anode and settling of matter from suswhich the delivery of chlorine begins immedlpension in the electrolyte. In determining the ately when the current is turned on; and in width of the spacer the thickness of a diaphragm which there is practically a coinplete separation and diaphragm retainer, or corresponding parts, 20

of hydrogen and caustic from the chlorine, when must also be taken into consideration. the electrolyte is a sodiumchloride brine, or a In the apparatus of Fig. l, the anode III has its corresponding separation when other electrolytes lower face I I formed to direct chlorine generated are used. on that face toward a central opening tenni- With the above and other objects and advannating in a riser l2. The anode l0 may be made 25 tages in view, all of which will become apparent from any suitable chlorine resisting material such later on, the invention consists in a novel combias. graphite or fused iron oxide. The riser 12 may nation and arrangement of parts, the novel feabe of any suitable material and mustbe of such tures of which are pointed out in appended diameter and size that the chlorine generated claims, and illustrative embodiments of which'are may bubble up through the electrolyte without 30 hereinafter described with reference to the drawcarrying electrolyte over' as the chlorine 'passes ings which accompany and form a part of the or is drawn from the riser to the connections specification. and other devices through which it passes to the In said drawings: point where it is to be applied. The anode is the Fig. l is a section through one of the cells and only portion of the cell which deteriorates at all 35 the associated devices'for supplying brine and frequently in use, but as will be seen, it is simple withdrawing the chlorine. in construction and may easily be replaced. It

Fig. 2 is a section illustrating on a larger scale may also, obviously, be of any desired thickness,

' than in Fig. 1 some of the details of the cell conthereby giving sufilcient material for long life 40 struction. without replacement. 40

Fig. 3 illustrates in' section a construction The spacer I3 is a ring of insulating material which varies in respects hereinafter stated from and forms what might be termed the vertical the one shown in Fig. 1. wall of the cell. Its width or height may be va- Fig. 4 is a section showing details of the conried according to requirements in making difstruction of a cell differing in some respects from ferent cells. 45 those shown in the other figures. The cathode against which caustic soda and Fig. 5 illustrates the construction of the screen hydrogen are generated by the electrolysis is or grid employed in certain forms of the cell, as, shown at M in Fig. 1. It consists of a material for instance, the one shownin Fig. 4. i which is resistant to corrosion by alkalis and by In addition to the constructions ,s'pecifically chlorine. The chlorine which comes in contact shown in the drawings other forms, some of which with the cathode is in relatively minute quantiwill be specifically mentioned later on, may be ties and is simply such chlorine as may not have employed, also forms of brine supplying and chloescaped to the riser l2 and which is carried down rine withdrawing devices varying from the ones in solution by the electrolyte which percolates illustrated, through the cathode as hereinafter explained, 55

but nevertheless it must be taken into consideration in selecting the cathode material.

The material for the cathode M may be graphite or silver, preferably, although other maf terials such as iron or iron containing one or have substantially vertical side walls.

more alloys to resist corrosion by alkalis and chlorine. However, silver is quite expensive and iron and all known iron alloys or compounds require relatively frequent replacement. Graphite for the cathode is, therefore, preferred. The advantages of silver as a cathode may be secured by using it in the form of a screen, as such a screen will have a long life and be satisfactory in many respects without a prohibitive cost.

The electrical equipment has not been shown in the drawings, as it may include any direct current generator, or any suitable kind of a rectifier, connected to the anode and cathode in the usual way. The usual-rheostat for regulating the flow of current and, consequently, the amount of current generated may be employed, also any suitable one of the usual indicating ammeters.

The caustic soda and hydrogen are generated or produced by the electrolysis on the upper horizontal surface of the cathode H3. The upper surface of the cathode is machined as at I5 to provide a number of concentric ribs. It is preferred to do this machining in sucha way that the ribs This machining may, of course, be done in such a way that the ribs are straight and parallel. That is to say, it does not make any difference whether the ribs are straight or circular. The important things for the best results are to have the side Walls of the ribs substantially vertical and the ribs sufficiently great in number to prevent having, on the upper face of the cathode, any large flat areas against which electrolysis will occur. The cathode also has a number of holes I6 drilled vertically through it. The number of holes may vary, but the number and the distribution must be such as to allow the alkali and hydrogen to escape freely from the ridged upper face of the cathode. In order to facilitate this escape, a number of cross channels at angles to the ribs and above the holes may be employed.

Resting upon the ridged or grooved upper face of the cathode is a porous diaphragm I! covering the entire electrolyzing surface. This diaphragm prevents the hydrogen generated op. the upper face of the cathode from rising into the electrolyte. It may be of any material suitable for the purpose, an asbestos paper being highly satisfactory. However, such a paper tends to become spongy after it is in use a short time, and it then begins to deteriorate or lose its efficiency. This difliculty is overcome by a porous, rigid member I8 resting on the diaphragm and holding it against the cathode. Pins I9 projecting from the spacer I3 may be used tohold the member I8 inplace. This maintains the diaphragm IT in effectiye condition toprevent the dum; or it may be a porous silicate-plate including a suitable bonding material, such as filtros .plates; or a, suitable perforated plate or screen a certain extent the rate of percolation through the holes I6 in the cathode. If the diaphragm should become loose and spongy its efiiciency in both respects would be decreased or lost. This is prevented by the member I8 holding the diaphragm compacted against the upper face of the cathode. If it is found that the diaphragm is nevertheless allowing percolation at too rapid a rate, a solution of an iron salt may be introduced into the electrolyzing chamber. This precipitates iron hydroxide in the diaphragm and reduces its porosity.

The construction as so far described gives a cell having quite extensive electrolyzing faces, with a container between them for the electrolyte holding a relatively shallow supply of the electrolyte.

The electrolyte preferred is a brineforme'd by dissolving sodium chloride or salt in water. The salt is dissolved in what may be termed a saturator comprising a container 2i of any desired shape and capacity. Water is introduced through a pipe 22 to the lower part of the container and allowed to rise through the salt 23. A float controlled valve 24 maintains the solution at a constant level in the container.

In the form of the apparatus shown in Fig. 1 the container is connected to the interior of the electrolytic cell by an inverted U-tube 25 of large bore extending through the spacer I3. When the operation of the cell is stopped, as hereinafter described, the U-tube serves to prevent brine from flowing into the cell, as the upper level of the brine in the cell will fall below the level of the upper part of the tube and break the connection to the saturator.

It is possible to operatethe cell by a gravity flow from the saturator 2|, but it is preferred to create a negative pressure or partial vacuum in the cell to effect the flow of electrolyte from the saturator to the cell. For this purpose the riser I2 is connected by a pipe 27 and branch 28 to some sort of a device, such as an aspirator 29 in a circuit of water or the like leading to the water supply or sewage which is to be chlorinated. The, lower end of the pipe 27 may extend into a float box or water seal 30. When the apparatus of Fig. 1 is in operation, the aspirator 29 will draw the chlorine from the top of the riser I2, and, at the same time, both fill the electrolyzing chamber and draw some of the electrolyte into the riser because of the negative pressure produced in the cell. The height of the liquid in the riser and cell are, in the present instance, controlled by the water seal or float box 30. Any tendency to raise the electrolyte in the riser is counteracted by the lift of water from 30, so the electrolyte is maintained at a substantially constant level while the apparatus is running. This arrangement gives highly satisfactory results in every respect. An added advantage is that this negative pressure or partial vacuum tends to prevent the escape of chlorine from the cell in case of leaks, as the chlorine will, instead of escaping from the cell, be drawn inward into the cell or some of its connections. The utility of this idea is not limited to cells such as herein shown and described, as the suction apparatus may obviously be employed in connection with cells in Wh ch the anodes and cathodes have verthrough the cathode remains substantially constant. This latter condition is because the operating head of electrolyte on the cathode is only the electrolyte below the level of the electrolyte in the container 2i and this head is not changed or varied by changes in the height at which the electrolyte is held by the aspirator. The level of c the electrolyte inthe container 2| and, consequently, the effective head above the cathode il may, however, be changed .by adjusting .thevalve 24 or the float controlling the valve.

When it is desired to stop the operation of the cell of Fig. 1, the current supply may be cut oil, or the aspirator shut off in any desired way, or

a valve 3| opened to allow air to enter the riser. When the valve is opened the level of the electrolyte will drop until it no longer contacts the under face of the anode in, thereby arresting the flow of electrolyzing current, and below the upper bend of the U-tube 25 to shut off flow of the electrolyte from the saturator 2|. When it is desired to put the cell again in operation the valve Si is closed or the aspirator turned on so that the aspirator w ll again raise the level of the electrolyte to the operating point;

As previously stated, hydrogen and an alkali are generated or developed on the upper face of the cathode It. What has been termed the al kali or, in some instances, the caustic soda, is mainly sodium hydroxide. These products are carried by the electrolyte percolating through the cathode into a drip pan 32 and may flow from that pan into a drain 33. The hydrogen and alkali may, however, be conducted to the aspirator so that they, as well as the chlorine, are introduced into the water or sewage which is to be sterilized. Hydrogen will reduce chlorine and destroy the potency of the latter if the two are in contact long enough. but in the present apparaus the period of contact in the l ne between the aspirator and the point of application is short. This, coupled with the fact that the chlorine has been greatly diluted when mixed with the water or sewage, prevents the hydrogen from interfer-' ing to any appreciable extent with the sterilizing efllciency of the chlorine. Instead of either of these constructions, the hydrogen may be allowed to escape to the air and the solution of caustic soda accumulated in a drip panwith a, connection to the aspirator to draw the solution out of the pan.

'This idea of using the hydrogen and caustic soda is shown in Fig. 3 of the drawings. The pan 32 is connected by a pipe 35 to pipe :6, closed by v a float box water seal 31, to the aspirator 29.

The apparatus in Fig. 3 also contains other variations froni the apparatus of Fig. 1. This consists in making the drip pan 32 airtight by a connection \sealing it against the cathode l4 and supplying to the aspirator so that, in addition to. drawing the hydrogen and caustic into the sterilizing circuit, the aspirator 29 will create a negative pressure below the cathode H as well as above the electrolyte in the electrolyzing chamber of the cell. This permits placing the saturator 2! port for'the diaphragm i I.

' engaging below the diaphragm n in the cell. In this form of the apparatus the flow oi the electrolyte from the container 2| is induced by a difference between the two negative pressures, that is, the one above the cathode and in the riser pipe l2 and the other below the cathode l4 and in the collecting chamber. This diiference in the two pressures results inlifting the electrolyte above the anode and into the riser pipe and gives a head above the diaphragm l1 suflicient to insure percolation. The difference between the two pressures may be varied by variations in the length of the piping between the float box 31 and the aspirator 29. As the length of this piping is increased or decreased the difference between the two negative pressures is varied accordingly. As'a result the height of the efiective head of electrolyte above the diaphragm I1 is raised or lowered and the rate of percolation increased or decreased. The same effect, that is, controlling the rate of percolation, may also be obtained by varying the level of the electrolyte in the saturator. This may be done by bodiiyraising or lowering the saturator, .by adjustment of the valve 24 in the saturator, by adjustment of the float con rolling the valve, or in any other way which will change the level of the electrolyte in the container of the saturator. In other respects the construction and operation of the apparatus of Fig. 3 are substantially the same as with the apparatus of Fig. 1.

Instead of machining the upper face of the cathode M to produce the numerous ribs as above described. the construction of Fig. 2 may be employed. 'In this form the upper face of the cathode is recessed as at 40 and filled with granules .for the diaphragm i1 is obtained, the construction is a very satisfactory one.

Another way of saving the machining opera.- tion on the upper face of the cathode is illustrated in Figs. a and 5. In this construction the upper face of the cathode is recessed enough to receive a screen or grid 42 which will give a firm sup- The holes in the screen or grid are so placed that when in assembled relation they will be in alignment with the upper ends of the holes drilled through the cathode. The grid or screen 42 may be made of iron, nickel or silver., Silver is the best and will last indefinitely.

No particular way of fastening the various parts o'f the cell has been illustrated. They might be fastened together with boits or with clamps above the anode l0 and under the cathode H, or in the apparatus of Fig. 3, under the drip pan". The simplest way, however, is to place weights on the flat top of the anode. They should, of course, he heavy enough to keep thecell sealed at all times. It is an easy matter to lift them off when the cell has to be opened.

This facilitates cleaning or replacement of parts. However, the materials used in the making of the cell are resistant to acids as well as to chlorine and caustic and the cell may be cleaned by opening the top of the riserand, while .the cell is empty or substantially so, pouring in a quantity 'of strong hydrochloric acid. This will dissolve -out' any impurities which have been deposited from the brine and carry them down through the diaphragm and restore the full percolating capacity of the cell. However, the necessity for cleaning may be largely prevented by using a special grade of salt which is free from calcium and magnesium. With such a grade of salt the operation can be continued indefinitely without the cell becoming plugged up by deposits on the diaphragm H or plate l8.

As stated above, silver in the form of a grid or screen may be used for the cathode. Iron may be used in the same way, but will not be as satisfactory. When the screen cathode is used the thickness and weight of the porous plate may be reduced or the plate omitted, although if it is omitted the exclusion of the hydrogen from the electrolyte is not as complete as is desirable for the best results.

While the constructions above mentioned, particularly the ones described and shown in the drawings, are admirably adapted to fulfill the purposes and give the advantages set forth, the inventions are capable of various embodiments, with suitable changes in the construction and arrangement of the parts, and it is not the desire to be limited in any way except'by such limitations as are contained in the claims which follow.

What is claimed is:

1. In an electrolyzing apparatus, an electrolyzing cell comprising an anode, a cathode, and an insulating ring between the edges of the cathode and the anode, said anode, cathode and insulating ring constituting the exterior walls of 'an electrolyzing chamber, ariser connected to an opening in the anode, means normally efiective to maintain the electrolyte at a constant level in the cell and riser, and devices whereby said means may be rendered ineffective when. desired,

2. In an apparatus of the character described, an electrolyzing cell, a container for a supply of electrolyte having a supply conduit leading from the container to the interior of the cell, said container being below the cell, and means connected to the interior of the cell for creating a partial vacuum in the cell to draw electrolyte from the container-through said conduit to fill the cell and maintain it at a constant level in the cell higher than the level of the electrolyte in the container.

3. In an apparatus of the character described, an electrolyzing cell comprising an upper and a lower electrode, a container for a supply of electrolyte, means for maintaining the electrolyte in said container at a level below the upper electrode, and means for drawing the electrolyte into the cell and maintaining it at such a level in the cell as to be in electrolyzing contact with the upper electrode and thereby establish and maintain an electrolyzing circuit between the upper and lower electrodes.

4. In an apparatus of the character described, an electrolyzing cell comprising an upper and a lower electrode, a saturator, means for maintaining brine in the saturator at a level below the upper electrode, an aspirator, connections from the aspirator to the cell and from the cell to the saturator whereby the aspirator will lift the brine from the saturator to fill the space between the two electrodes, and means cooperating with the ode, said anode, cathode and ring collectively.

constituting the exterior walls of a closed cell, a container for electrolyte, supply connections fromthe container leading into the interior of the cell, means for maintaining the electrolyte in the container at a level below the anode, and an exhaust means connected to the interior of the cell for drawing the electrolyte into the cell and maintaining it in contact with the anode.'

6. In an electrolyzing apparatus, an electrolyzing cell comprising an anode, a cathode, and a spacing ring of insulating material between the anode and. cathode and, in cooperation with said anode and cathode, enclosing an electrolyzing compartment, a riser leading from an opening in the anode, a source of supply of electrolyte con nected to the interior of the electrolyzing compartment, and means connected to the riser for drawing electrolyte from the source of supply to fill the cell and maintain the electrolyte at a constant level in the riser.

. '7. In an apparatus of the character described, an electrolyzing cell comprising an upper electrode, a lower electrode, a spacer between the edges of the electrodes and cooperating with the electrodes to enclose an electrolyzing chamber, a saturator, means for maintaining the electrolyte in the saturator at a level above the electrolyzing face of the lower electrode and below the electrolyzing face of the upper electrode, suction devices for drawing the electrolyte from the saturator into the cell and into contact with the electrolyzing face of the upper electrode, and devices whereby the suction devices may be rendered ineffective upon the electrolyte.

8. In an apparatus of the character described, comprising ananode having a single opening therethrough, a cathode, an insulating ring separating the anode and cathode and, in combination with the anode and cathode, enclosing an electrolyzing chamber, devices connected to the aforesaid opening for creating a partial vacuum in the chamber, a container for a supply of electrolyte, and connections leading from said source of supply to the interior of the electrolyzing' chamber, operation of the vacuum devices lifting electrolyte from the supply container through said connections into the electrolyzing chamber and carrying offthe gas evolved by electrolysis in said chamber.

9. -In an apparatus of the character described comprising an anode having an opening near its center and a riser in said opening, a cathode, an insulating ring separating the anode and the cathode and, in combination with the anode and cathode, enclosing an electrolyzing chamber, a container for a supply of electrolyte connected to the interior of said chamber, and devices connected to the riser for drawing electrolyte from the supply to-fill the chamber and partially fill the riser.

10. In an electrolyzing apparatus an electrolyzing cell comprising an anode, a cathode and an insulating ring between the anode and the oath-' ode, said anode, cathode and ring constituting the enclosing walls of the cell, a container for connected to the anode for drawing electrolyte from the container to fill the cell and thereby establish a circuit between the anode and the cathode.

11. In an electrolyzing apparatus, an electrolyzing cell comprising an anode, a cathode and,

an insulating ring between the cathode and the anode, said anode, cathode and insulating ring constituting the walls or the cell, a container for a supply of electrolyte and connections extending through the insulating ring to the interior of the cell, means for maintaining the electrolyte in the container at a level below the upper edge of the ring, and means connected to the anode for drawing electrolyte from the container to fill the cell and thereby establish a circuit between the anode and the cathode, and devices cooperating with said means to maintain the electrolyte at a constant level in the cell.

12. In an electrolyzing apparatus, an electrolyzing cell comprising an anode having its lower face inclined from its edges upward toward its center with a riser leading from an opening at said center, a cathode having a plurality of holes to allow electrolyte to escape, a spacer ring between the anode and the cathode and, in cooperation with the anode and cathode, enclosing the electrolyzing chamber, a filter on the upper face of the cathode, means for holdingthe filter against the face of the cathode, means carried by the cathode presenting surfaces of small areas in contact with the filter, and devices connected to the riser for drawing electrblyte from a source of supply to fill the cell and maintain a constant level in the riser.

13. In an electrolyzing apparatus, an electrolyzing cell comprising an anode having a lower face inclined from its edges upward toward its center,with a riser from an opening in said center, a cathode having a plurality of holes to allow electrolyte to percolate, a spacer ring between the anode and the cathode and, in cooperation with the anode and cathode, enclosing the electrolyzing chamber, a filter means carried by the cathode supporting the filter and constructed to provide surfaces of such small area as to permit the products of electrolysis to escape readily from between said surfaces and the filter, a porous,

non-resistant plate resting upon the filter, and

means connected to the riser for drawing electrolyte from a source of supply to fill the cell and maintain the electrolyte at a constant level in the cell.

14. In an electrolyzing apparatus, an electrolyzing cell having an enclosed electrolyzing chamber, an aspirator operatively connected to the interior of said chamber, devices connected to'the interior of the chamber and requiring operation-of the aspirator for maintaining a supply of electrolyte in the electrolyzing chamber, and means for regulating the aspirator to vary the amount of electrolyte maintained in said chamber. a

15. In an electrolyzing apparatus, an electrolyzing cell containing a horizontal anode and a horizontal cathode spaced apart to form an electrolyzing gap between them, an aspirator connected to the interior of the cell between the anode and the cathode, a saturator comprising means for maintaining brine at a level lower than the anode-and devices whereby operation of the aspirator will lift the electrolyte into electrolyzing contact with the anode and maintain said electrolyte at a constant level with respect tothe anode.

16. In an apparatus of the character described, an electrolyzing cell comprising an anode and a cathode, a member for holding a supply of electrolyte in contact with the anode and the oathode, an aspirator, a saturator, and connections from the aspirator to the cell and from the cell to the saturator whereby the aspirator will lift brine into electrolyzing relation to the anode and the cathode.

17. In an electrolyzing apparatus, an electrolyzing cell comprising an anode, a cathode, and a member composedof insulating material between the anode andthe cathode, said anode, cathode and member forming the enclosing walls of the cell and the anode being constructed'with smooth interior surfaces converging upward toward an opening in the anode, a riser connected to said opening, devices connected to the riser for drawing from the interior of the cell the gaseous product of the electrolysis, said devices also serving to raise the electrolyte in the. cell to establish a circuit between the anode and the cathode, and a supply container for the electrolyte connected to the interior of the cell.

JOHN c. BAKER.

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