US3562138A

US3562138A - Structural element for use in an electrolytic cell

Info

Publication number: US3562138A
Application number: US784632A
Authority: US
Inventors: Rudolf H Hausler
Original assignee: Universal Oil Products Co
Current assignee: Universal Oil Products Co
Priority date: 1968-12-18
Filing date: 1968-12-18
Publication date: 1971-02-09
Anticipated expiration: 1988-02-09

Abstract

A STRUCTURAL ELEMENT OF AN ELECTROLYTIC CELL COMPRISING AN ELECTRICALLY INSULATING SOLID ELEMENT PERFORATED BY PARALLEL HOLES, ONE OF WHICH IS CENTRALLY LOCATED IN THE MEMBER AND THE REMAINDER OF WHICH ARE SYMMETRICALLY POSITIONED AROUND SAID CENTRAL HOLE, TWO OF THE OPPOSING SYMMETRICALLY POSITIONED HOLES ARE CONNECTED TO SAID CENTRAL HOLE BY PASSAGEWAYS, AND EITHER A SEMIPERMEABLE DIAPHRAGM OR AN ELECTRODE IS POSITIONED TRANSVERSELY ACROSS SAID CENTRAL HOLE. A PLURALITY OF THESE STRUCTURAL ELEMENTS CAN BE LINEARLY ARRANGED TO ALLOW THE INTRODUCTION AND WITHDRAWAL OF ANOLYTE, CATHOLYTE, AND COOLANT, IN THE ALTERNATIVE TO THE CAVITIES BOUNDED BY THE STRUCTURAL ELEMENTS AND THE DIAPHRAGMS AND ELECTRODES CONTAINED THEREIN, THEREBY FORMING A SERIES OF ELECTROLYTIC CELLS.

Description

Feb. 9, 1971 R. H. HAUSLER STRUCTURAL ELEMENT FOR USE IN AN ELECTROLYTIC CELL 2 Sheets-Sheet 1 Filed Dec. 18, 1962 IN VENTOR. Rudolf H. Haas/er BK T d5 ATTORNEYS United States Patent 3,562,138 STRUCTURAL ELEMENT FOR USE IN AN ELECTROLYTIC CELL Rudolf H. Hausler, Arlington Heights, Ill., assignor to Universal Oil Products Company, Des Plaiues, Ill., a

corporation of Delaware Filed Dec. 18, 1968, Ser. No. 784,632 Int. Cl. B01k 3/00 US. Cl. 204-279 12 Claims ABSTRACT OF THE DISCLOSURE tion and withdrawal of anolyte, catholyte, and coolant,

in the alternative to the cavities bounded by the structural elements and the diaphragms and electrodes contained therein, thereby forming a series of electrolytic cells.

This invention pertains to a structural element of an electrolytic cell comprising an electrically insulating solid member perforated by several parallel holes, one of which is centrally located in the member. The remaining holes are symmetrically positioned around said central hole. Of these remaining holes, two opposing symmetrically positioned holes are connected to said central hole by passageways. In the alternative, the passageway may be so Wide that instead of these being separate holes, there is only a single hole having two peripheral portions symmetrically arranged with respect to the central portion. An electrical element, either a semipermeable diaphragm or an electrode is positioned transversely across the central hole or central portion. The solid member may be either a uni tary structure or it may be comprised of several rigidly joined components.

A plurality of the structural elements can be linearly arranged to allow the introduction and withdrawal of anolyte, catholyte, and coolant, in the alternative to the cavities bounded by the structural elements and the electrical elements positioned therein, thereby forming a series of electrolytic cells. The unique construction of the aforesaid structural element for an electrolytic cell provides structural units which accommodate anodes, cathodes, and diaphragms interchangeably, while requiring no exterior shell or casing to hold electrolyte or coolant for the cell. Furthermore, the sequential arrangement of anodes, cathodes, and semipermeable diaphragms can be varied merely by rearranging the sequence of structural elements used, since the structural elements are of modular design. For the same reason, both the electrical capacity and the physical size of the cell can be readily varied to meet changing requirements. Some possible variations of the cell configurations which can be formed using the structural elements of the present invention are cells in series, cells in parallel, cells in which some cavities between individual cells are bounded on both sides by anodes, and other cavities between individual cells are bounded on both sides by cathodes, and cells having various other predominant features as a result of the manner of assembly of the structural elements.

In addition, while electrolytic cells of modular design currently exist, no conventional electrolytic cells of moduice lar design provide either the flexible system of electrolyte delivery and withdrawal nor the effective heat removal system made possible by the invention disclosed herein. A series of the electrolytic cells constructed of elements designed according to the present invention requires no external supply lines or manifold arrangement for the supply and withdrawal of anolyte, catholyte, and coolant. Instead, anolyte, catholyte, and coolant may each be supplied in parallel to selected cell cavities, in series to selected cell cavities, or a common electrolyte may be supplied to all cell cavities.

It is a primary object of this invention to provide structural elements of electrolytic cells which are easily and interchangeably assembled to form different cell configurations. Changes in cell configuration are effected by changing the sequential alignment and relative positioning of individual structural elements.

Another object is to provide structural elements of electrolytic cells into which the supply and withdrawal system for electrolytes and coolant is integrally formed.

It is a further object of the present invention to control the temperatures uniformly throughout the electrolytes in a series of cells constructed of a number of the aforesaid structural elements. The structural components of this invention are such that a cooling system is incorporated as an integral part of the electrolytic cell structure. Either an increase or decrease in temperature may be effected in the temperatures of the electrolytes of the cells merely by decreasing or increasing the flow of coolant through the cooling cavities formed by the structural elements.

In one embodiment, this invention is a structural element of an electrolytic cell comprising an electrically insulating solid member perforated by at least seven parallel holes and further characterized in that: a first of said holes is centrally located with respect to the perforated surfaces of said member; six remaining holes are of uniform cross-sectional dimensions; said six remaining holes are symmetrically arranged about said first hole; passageways in said member connect two of the symmetrically arranged holes with said first hole; a solid electrical conductor extends from said first hole through said member to the exterior surface of said member; an electrolytic cell element is positioned transversely across said first hole, thereby contacting said electrical conductor; the perforated surfaces of said member are contoured to fit snugly against the opposing surfaces of identical adjacent members in at least three positions of relative rotation between adjacent members, whereby the parallel holes of adjacent members form parallel passageways.

A preferred embodiment of this invention is a structural element of an electrolytic cell comprising an electrically insulating solid member perforated by at least five parallel holes and further characterized in that: a first of said holes has a first portion centrally located with respect to the perforated surfaces of said member, and at least two identical peripheral portions symmetrically arranged about said first portion; the remaining holes have cross-sectional dimensions identical to those of said peripheral portions of said first hole; said remaining holes are symmetrically arranged about said first portion of said first hole; an electrolytic cell element is positioned transversely across said first portion of said first hole; a solid electrical conductor extends transversely from said electrolytic cell element to the exterior surface of said solid member; and the perforated surfaces of said member are contoured to fit snugly against the opposing surfaces of identical adjacent members in at least three positions of relative rotation between adjacent members, whereby the parallel holes of adjacent members form parallel passageways.

In this preferred form, the insulating solid member normally is of circular cross section. The first portion of the first of said holes is also normally of a smaller circular cross section and is concentric with respect to the cross section of the solid member. The peripheral portions of the first hole and the remaining holes each have cross sections which are those portions of sectors emanating from the center of the solid member which are limited by arcs of the aforesaid concentric circles.

In an alternative form this invention is a structural element of an electrolytic cell comprising an electrically insulating solid first member perforated by a hole and further characterized in that: peripheral members are positioned adjacent to said first member and form six holes in the structural element all of which are parallel to each other and parallel to the hole in said first member; the six holes formed by the peripheral members are of uniform cross-sectional dimensions; said six remaining holes are symmetrically arranged about said first hole; passageways through said first member connect two of the symmetrically arranged holes with said first hole; a conductor passageway extends transversely through said first member connecting said first hole to an external surface of said first member; a solid electrical conductor is inserted in said conductor passageway and extends from said first hole to at least the surface of said member; an electrolytic cell element is positioned transversely across said first hole, thereby contacting said electrical conductor; and the transverse surfaces of said members are contoured to be sealed against the opposing surfaces of identical mating members of adjacent structural elements in at least three positions of relative rotation between adjacent members whereby the parallel holes of adjacent members form parallel passageways.

A plurality of such structure elements linearly aligned and provided with appropriate direct current connections forms a series of electrolytic cells through which an anolyte, a catholyte, and a coolant flow to effect the desired chemical and thermal reactions. The term anolyte, as used herein, refers to the electrolyte which eifects a reaction with the anodes of the cells. Catholyte refers to the electrolyte which effects a reaction with the cathodes of the cells. Normally the anodes are comprised of a different conductive material than are the cathodes in a cell series, though there is no requirement as to such a difference in composition. The diaphragms are frequently ion exchange membranes, although they may be comprised of any other semi-permeable material well known in the art.

The present invention may be used to form electrolytic cells in which any electrolytic oxidation or reduction process takes place, but preferably is used where significant amounts of gas are not produced at the electrodes. This preference of application exists because there must be a vent or gas withdrawal line provided to enable any gas produced at an electrode to be withdrawn. If such a venting arrangement is not present, the gas bubbles produced will displace electrolyte at the electrodes and thereby reduce the surface available for contact between the electrodes and the electrolytes. The present invention may be used where any liquid is being converted to another liquid, where metal is being plated, or where some other chemical or physical change other than gas generation takes place.

Because of the cooling system provided by cells utilizing this invention, the available applications are not limited to inorganic electrolytic cells, but include organic electrolytic cells in which heat removal is necessary. Some of the more commercially important of such applications are: the reduction of aromatics, methoxylation of olefins, acetoxilation of aromatics, hydrodimerization of olefins, reduction of carboxylic acids, reduction of aromatic ketones, esters, and nitro compounds, as well as electrochemical reactions in numerous other organic chemicals.

In the embodiment of the structural element having at least five parallel holes, said solid member is a disk and one of said perforated surfaces is provided with protuberances and the other perforated surface is provided with indentations which accommodate and grasp the aforesaid protuberances, whereby a plurality of said members may be arranged in a series and remain in contact. This arrangement has the advantage of requiring no external axial compressive force to hold the structural elements in alignment and preserve unbroken the passages formed by the holes of the mating structural elements. When said protuberances are used to hold the structural elements in alignment, the protuberances symmetrically arranged with respect to the axis of the structural element thereby enable the structural elements to be stacked in various positions of relative rotation. The protuberances may extend through gaskets which may be used to seal the interfaces between the structural elements.

An alternative modification of this embodiment of the invention utilizes additional holes which are symmetrically arranged about said first hole and extend through said perforated surfaces, whereby fastening means can be extended through said additional holes in a series of said members, thereby holding said members tightly together. This embodiment may similarly be used with or without gaskets between the structural elements. In either case, fastening means, such as bolts, helical springs, and the like, extend linearly through a series of the structural elements, wherein the structural elements are compressed together thereby defining a series of electrolytic cells. Each structural element has positioned transversely therein an electrical element, which in the alternative is either a cathode, anode, or diaphragm. All of the anodes are connected to the positive terminal of a direct current source while all of the cathodes are connected to the negative terminal of the direct current source. In one type of cell system, all of these electrical elements are substantially planar in shape and form a confining boundary in an axial direction through which the anolyte, catholyte, and coolant cannot fiow. All the chemical reaction then takes place at the surfaces of the anodes and cathodes which are in contact with the electrolytes.

The cell elements of this invention are adaptable to a cell series utilizing a conventional linear electrolyte flow. In such a cell arrangement, the anodes and cathodes are both perforated with holes and the diaphragms are omitted. The same electrolyte is then used both as an anolyte and a catholyte, and no coolant issued. The electrolyte is forced from one end of the cell series to the other through the perforations in the electrical cell elements.

Circumferentially around the inner surface of the first hole or central portion of the first hole, is a groove into which an electrical element fits. The groove is deep enough to hold the electrical element firmly, yet not so deep as to create difiiculty in changing electrical elements. This groove facilitates the proper fluid tight positioning of the electrical element when it is inserted into the first hole or the central portion of the first hole. In any electrolytic cell arrangement, each adjacent group of three structural elements is comprised of one cathode, one anode, and one diaphragm, though not necessarily in any identical repeated pattern. In one arrangement the structural element containing a diaphragm is posisitioned between the structural element containing an anode and the structural element containing the cathode in each group of three structural elements, thereby forming one complete cell. Using this arrangement, each interior anode is positioned adjacent to the cathode of an adjoining cell, and each interior cathode is positioned adjacent to the anode of an adjoining cell. Interior anodes and cahtodes as discussed herein, are electrodes which are not positioned at either end of a series of cells. In the cell construction described, the cavities linearly bounded by the anode and the diaphragm of each cell are each appropriate for accommodating a flow of anolyte, the cavities linearly bounded by the cathode and the diaphragm of the cell are appropriate for the accommodation of a flow of catholyte, and the cavities linearly bounded by the anode and the cathode of adjacent cells are appropriate for accommodating the flow of coolant.

In an alternative form of the same arrangement, each interior anode is positioned adjacent to the anode of the adjoining cell, each interior cathode is positioned adjacent to the cathode of an adjoining cell, and the diaphragm of each cell is positioned between the anode and the cathode of that cell. In this cell construction, the cavities linearly bounded by adjacent anodes of adjacent cells are appropriate for accommodating the flow of electrolyte, the cavities linearly bounded by adjacent cathodes of adjacent cells are appropriate for accommodating a flow of catholyte, and the cavities bounded by the anode and the diaphragm of the cell and the compartments bounded by the diaphragm and the cathode of each cell are appropriate for accommodating a flow of coolant. In an alternative arrangement, the anolyte may flow through the compartments bounded by the anode and the diaphragm of each cell, the catholyte may flow through the cavities bounded by the cathode and the diaphragm of each cell, and the coolant may flow through the cavities bounded by adjacent elements of adjacent cells, that is, the cavities bounded by adjacent anodes and adjacent cathodes.

All of the aforesaid cell configurations are examples of parallel flow of the anolyte, catholyte, and coolant. In parallel flow, a part of a fluid flows into certain cavities, the rest of that fluid flows on through the passageways formed by the symmetrical holes. In a series flow of anolyte, catholyte and coolant, however, all of the anolyte follows a single path through certain cavities in the cell series. All of the catholyte flows on a separate path through certain cavities, and the coolant flows in yet another distinct path through specific cavities.

In a series flow arrangement, there must be certain partitions or blocks inserted in the symmetrically arranged holes to channel the entire flow of each electrolyte or coolant through the desired cavities in a single ath.

P The series connections of elements can be used with the same structural elements as heretofore described. There will be no difference in the operating conditions Whether the cells are electrically connected in series or in parallel. In cells electrically connected in series, the same current passes through all cell elements, therefore a uniform temperature will be maintained throughout the length of the cell series because the heat produced within the cells depends upon the current density through the electrolyte. In cells electrically connected in parallel, the heat produced in all the cells contacted will be substantially the same because again substantially the same current will flow through each cell unless there is a separate electrical adjustment changing the electrical resistance through any cell.

In embodiments of the structural element where applicable, the transverse passageways connecting two of the symmetrically arranged holes with the central hole may extend either internally through the wall of the electrically insulating solid member, or they may comprise channels across one transverse face of the electrically insulating solid member.

The various features of the present invention are further illustrated in the accompanying drawings in which:

FIG. 1 is an end view of one preferred embodiment of a single structural element.

FIG. 2 is a perspective view of another embodiment of a single structural element.

FIG. 3 is a sectional view of another embodiment of a single structural element.

FIG. 4 is a sectional view of a series of structural elements of still another embodiment.

'Referring now to FIG. 1, a structural element 1 is comprised of an electrically insulating solid member 22 perforated by a central hole 6, and by six other holes 8 of uniform circular cross-sectional area symmetrically positioned around the central hole 6. Holes 8 are positioned 60 apart around hole 6. This allows a plurality of adjacent structural elements 1 to be positioned in 6 different positions of relative rotation with respect to each other. Additional holes 23 of uniform cross section are symmetrically arranged about hole 6. Compression fastening means can be extended through the holes 23 of linearly aligned structural elements 1, thereby holding the structural elements 1 tightly together. There are passageways 24 connecting two of the holes 8 to center hole 6. The holes 8 so connected are positioned apart with respect to the center of hole 6. Circumferentially around the inner surface of hole 6 is a groove 26 into which an electrolytic element fits. The groove 26 is deep enough to hold the electrolytic element firmly, yet not so deep as to create difficulty in changing electrical elements. A solid electrical conductor 25 extends transversely from an exterior surface of member 22 to groove 26 of the electrolyte.

FIG. 2 illustrates another embodiment of the single structural element of this invention. Structural element 1 is comprised of an electrically insulating solid first member 5 perforated by a hole 6. Peripheral members 7 are positioned adjacent to the first member 5 thereby forming six holes in structural element 1'. These six holes are designated as holes 8'. Holes 8 are of uniform semicircular cross section and are all parallel to each other and parallel to and symmetrically arranged around hole 6. Passageways 24' through member 5 connect two of holes 8' with hole 6'. A conductor passageway extends transversely through member 5 connecting hole 6' to an external surface of member 5. A solid electrical conductor 25 is inserted in the conductor passageway and extends from hole 6' to. beyond the external surface of member 5 where it can be connected to a battery terminal. An electrical element 11, either an anode, cathode, or diaphragm is positioned transversely across hole 6. While it is necessary for an anode or cathode positioned across hole 6' to be in contact with electrical conductor 25', such contact is unnecessary with respect to the diaphragm, though contact of the electrical conductor 25 with the diaphragm in no way hinders the operation of the cell.

In FIG. 3 there is shown a structural element 1" having a central hole about which is symmetrically arranged a plurality of separate holes, two of which are connected to the central hole by passageways. Surface 27 of structural element 1", one of the transverse perforated surfaces of disk 22, is provided with protuberances 28. The other transverse surface, surface 29, is provided with indentations 30. Indentations 30 accommodate and grasp the protuberances 28 of an adjacent structural element 1", thereby allowing a plurality of members 22 to be arranged in a series and remain in contact with each other.

Referring now to FIG. 4 there is shown a series of six structural elements linearly connected to form two complete electrolytic cells. Each structural element 1 is comprised of an electrically insulating solid member 22 perforated by a central hole 6, and by six other holes 8 of uniform circular cross-sectional area symmetrically positioned around the central hole 6. Holes 8 are positioned 60 apart around hole 6. This allows a plurality adjacent structural elements 1 to be positioned in 6 different positions of relative rotation with respect to each other. Additional holes 23 of uniform cross section are symmetrically arranged about hole 6. Compression fastening means can be extended through the holes 23 of linearly aligned structural elements 1, thereby holding the structural elements 1 tightly together. There are passageways 24 connecting two of the holes 8 to center hole 6. The holes 8 so connected are positioned 180 apart with respect to the center hole 6. Circumferentially around the inner surface of hole 6 is a groove 26 into which an electrolytic element fits. The groove 26 is deep enough to hold the electrolytic element firmly, yet not so deep as to create difficulty in changing electrolytic elements. The parallel passageways formed by adjacent holes 8 of the linearly aligned structural elements 1 are used to supply and withdraw anolyte, catholyte, and coolant to and from the cells. Electrolyte and coolant are prevented from escaping from the system by

end pieces

2 and 4. The supply and withdrawal of electrolyte and coolant is effected by means of pipes 14 and extending through end piece 4 and into the holes 8 adjacent to end piece 4.

The structural elements 1 and the

end pieces

2 and 4 are separated from adjacent members of the cells by gaskets 3. Gaskets 3 are perforated at locations which correspond to

holes

6, 8 and 23 of structural elements 1. Fastening bolts 12 equipped with fastening nuts, extend through holes 23 of structural elements 1 and through the corresponding holes of gaskets 3 and

end pieces

2 and 4, thereby compressing and sealing structural elements 1 in their linear alignment. There are three fluid inlets 14 extending through end piece 4 (only one of which is visible) and there are three fluid outlets 15 extending through end piece 4. The Visible inlet 14 connects the cell system to an anolyte supply source. The other inlets 14 (not illustrated) connect the cell system to catholyte and coolant supply sources. Outlets 15 connect the cells to anolyte, catholyte and coolant withdrawal sinks as illustrated. Thus, anolyte flows from the anolyte supply source to an inlet 14 and into the upper passageway, as formed by holes 8, and through passagesways 24 in the structural elements in which anodes 10 are positioned. The anolyte flows into cavities bounded by the anodes 10 on one side and by the next adjacent electrical elements on the other, which as illustrated, are diaphragms 19. The anolyte is withdrawn through opposite passageways 24' and flows through the lower passageway formed by holes 8 until it leaves the cell system through a fluid outlet 15. Similarly catholyte passes through passageways 24 into the cavities which are bouned by diaphrags 19 and cathodes 18 and leaves the cell system through a fiuid outlet 15. Coolant similarly flows through the cavities which are bounded by a cathode 18 and an anode 10 and by a cathode 18 and end piece 2. Coolant then leaves the cell system through a fluid outlet 15.

Also present but not visible are the connections of the anodes 10 by electrical conductors to the positive terminal of a battery and the connection of the cathodes 19 by electrical conductors 25 to the negative terminal of the battery. An example of some possible substances and materials which may be used in FIG. 4 are: sulfuric acid as anolyte, hydrochloric acid as catholyte, and cold water as coolant. Structural element 1 may be constructed of plastic, anodes 10 of copper, cathodes 18 of zinc, and diaphragms 19 of paperboard. Electrode posts 25 may be constructed of carbon.

Nothing herein is to be construed as limiting the scope of the invention to the embodiments illustrated, nor limiting the materials of which the anodes, cathodes, and diaphragms, or electrically insulating members are constructed. Neither are the liquids comprising the anolyte, catholyte and coolant to be limited, nor is the number of cells nor the geometric shapes of the anodes, cathodes, diaphragms, and structural elements to be considered limited. Also, the sequencing arrangement of the anodes, cathodes and diaphragms are not to be limited to those described herein.

What is claimed is:

1. An electrolytic cell comprising an electrically insulating solid member perforated by at least five parallel holes and further characterized in that:

(a) a first of said holes is centrally located with respect to the perforated surfaces of said member,

(b) the remaining holes are of uniform cross-sectional dimensions,

(c) said remaining holes are symmetrically arranged about said first hole,

(d) a first set of passageways in said member connect two of said symmetrically arranged holes with said first hole,

(e) a solid electrical conductor extends from said first hole through said member to the exterior surface of said member,

(f) an electrolytic cell electrode is positioned transversely across said first hole and in contact with said electrical conductor,

(g) the perforated surfaces of said member are constructed and arranged to fit snugly against the opposing surfaces of identical adjacent members in at least three positions of relative rotation between adjacent members, whereby the parallel holes of adjacent members form a second set of parallel pasageways.

2. The cell of claim 1 further characterized in that said first set of passageways connect two and only two of said symmetrically arranged holes with said first hole.

3. The cell of claim 1 further characterized in that said solid member is a disk and one of said perforated surfaces is provided with protuberances and the other perforated surfaces is provided with indentations which can accommodate and grasp corresponding protuberan-ces of an adjacent identical such member whereby a plurality of said members" may be arranged in a series and remain in contact.

4. The cell of claim 1 further characterized in that additional holes are symmetrically arranged about said first hole and extend through said perforated surfaces, whereby fastening means can be extended through said additional holes of a series of said members thereby holding said members tightly together.

5. An electrolytic cell comprising an electrically insulating solid member perforated by at least seven parallel holes and further characterized in that:

(b) six remaining holes are of uniform cross-sectional dimensions,

(0) said six remaining holes are symmetrically arranged about said first hole,

(d) passageways in said member connect two of the symmetrically arranged holes with said first hole,

(g) the perforated surfaces of said member are constructed and arranged to fit snugly against the opposing surfaces of identical adjacent members in at least three positions of relative rotation between adjacent members whereby the parallel holes of adjacent members form parallel passageways.

6. The cell of claim 5 further characterized in that said parallel holes are of circular cross section.

7. The cell of claim 5 further characterized in that said two symmetrically arranged holes, which are connected to said first hole by passageways, are positioned apart with respect to the center of said first hole.

8. An electrolytic cell comprising a structural element of an electrically insulating solid first member perforated by a hole and having opposing transverse surfaces and further characterized in that:

(a) six peripheral members having opposing transverse surfaces and are positioned adjacent to said first member and form six holes in the structural element all of which are parallel to each other and parallel to the hole in said first member,

(d) passageways through said first member connect two of the symmetrically arranged holes with said first hole,

(e) a conductor passageway extends transversely through said first member connecting said first hole to an external surface of said first member,

(f) a solid electrical conductor is inserted in said conductor passageway and extends from said first hole to at least the surface of said members,

(g) an electrolytic cell electrode is positioned transversely across said first hole and in contact with said electrical conductor,

(h) the transverse surfaces of said members are constructed and arranged to be sealed against the opposing surfaces of identical mating members of adjacent identical structural elements in at least three positions of relative rotation between adjacent members whereby the parallel holes of adjacent members form parallel passageways.

9. The cell of claim 8 further characterized in that said two symmetrically arranged holes, which are connected to said first hole by passageways, are positioned 180 apart with respect to the center of said first hole.

10. An electrolytic cell comprising an electrically insulating solid member perforated by at least seven parallel holes and further characterized in that:

(b) six remaining holes are of uniform cross-sectional dimensions,

(c) said six remaining holes are symmetrically ar ranged about said first hole,

(f) an electrolytic cell diaphragm is positioned transversely across said first hole and in contact with said electrical conductor,

*(g) the perforated surfaces of said member are constructed and arranged to fit snugly against the opposing surfaces of identical adjacent members in at least three positions of relative rotation between adjacent members form parallel passageways.

1 1. An electrolytic cell comprising a structural element of an electrically insulating solid first member perforated by a hole and having opposing transverse surfaces and further characterized in that:

(a) six peripheral members having opposing transverse surfaces are positioned adjacent to said first member and form six holes in the structural element all of which are parallel to each other and parallel to the hole in said first member,

(b) the six holes formed by the peripheral members are of uniform cross-sectional dimensions,

(c) said six holes are symmetrically arranged about said first hole,

(f) a solid electrical conductor is inserted in said conductor passageway and extends from said first hole to at least the surface of said member,

(g) an electrolytic cell diaphragm is positioned transversely across said first hole and in contact with said electrical conductor,

12. An electrolytic cell comprising an electrically insulating solid member perforated by at least five parallel holes and further characterized in that:

(a) a first of said holes is centrally located with respect to the perforated surfaces of said member, (b) the remaining holes are of uniform cross-sectional dimensions,

(c) said remaining holes are symmetrically arranged about said first hole, (d) a first set of passageways in said member connect two of said symmetrically arranged holes with said first hole,

(g) the perforated surfaces of said member are constructed and arranged to fit snugly against the opposing surfaces of identical adjacent members in at least three positions of relative rotation between adjacent members, whereby the parallel holes of adjacent members form a second set of parallel passageways.

References Cited UNITED STATES PATENTS 1,272,397 7/ 1918 Dohmen 204-256 2,933,444 4/1960 Bott 204253 2,969,315 1/1961 Bacon 2042-84 WINSTON A. DOUGLAS, Primary Examiner H. A. FEELEY, Assistant Examiner U.S. C1.X.R.