Frame for a cell construction

A frame and membrane assembly for a liquid transfer cell wherein the frame has a peripheral portion including opposite faces and one face is planar and the opposite face carries a peripherally outer sealing ring and inwardly thereof an anchoring arrangement for the membrane. Most specifically the anchoring arrangement is in the form of a peripheral groove of a generally dovetail cross section with an outer peripheral portion of the membrane being seated within that peripheral groove and retained therein in interlocked relation by way of a continuous second sealing ring. The second sealing ring, when the cell is assembled, is squeezed so as to both more tightly interlock the membrane with the frame and to form an inner seal between the two adjacent frames.

This invention relates in general to new and useful improvements in cell 
constructions, and more particularly to a frame for a cell construction. 
Cells of the type including a plurality of frames with membranes clamped 
between two adjacent frames are well known. However, difficulties have 
been experienced in effectively assembling such cells and more 
particularly the positioning and clamping of the membrane between the 
adjacent frames while maintaining a good seal between the adjacent frames. 
In one type of cell construction, an effective seal has been obtained 
between adjacent frames by utilizing a compressible sealing ring. However, 
the membranes must also be clamped between two adjacent frames and in the 
past in order to accomplish this, one of each pair of opposing frame 
surfaces is provided with projections which generally bite into the 
membrane and force the membrane against the other frame surface. It has 
been found that this arrangement has not been satisfactory for the 
positioning of a membrane and maintaining such membrane in that position. 
In accordance with this invention, one frame surface of each of a pair of 
opposing frame surfaces is provided with a generally dovetailed cross 
sectional groove and associated with that groove is a second sealing ring. 
Thus when the two frame surfaces are clamped together, the outer sealing 
ring forms a positive seal preventing escape of liquid from between the 
two frames while the inner resilient sealing member is deformed so as to 
stretch the membrane within the dovetailed cross sectional groove and 
positively maintain the membrane in position. 
In addition, the second sealing ring also serves to aid in forming a seal 
against the escape of liquid from between the two frames. 
With the above and other objects in view that will hereinafter appear, the 
nature of the invention will be more clearly understood by reference to 
the following detailed description, the appended claims, and the several 
views illustrated in the accompanying drawing.

Referring now to the drawings in detail, it will be seen that there is 
illustrated in FIG. 1 a known electrochemical cell generally identified by 
the numeral 10. The cell 10 is formed of a plurality of frames 12 with 
there being between adjacent frames 12 a membrane 14. Each cell 10 also 
includes an end plate 16. The end plate 16 and the frames 12 have conduit 
means therein for the inflow and outflow of liquids which are being 
treated. These, however, form no part of the invention. 
Referring now to FIG. 2, it will be seen that the known frame 12 has a 
peripheral joining portion 18 which includes a planar face 20 and a 
configurated face 22. The configurated face 22 includes a peripheral 
groove 24, which is rectangular in cross section. A resilient sealing ring 
26 is seated in the groove 24 for engagement with the planar surface 20 of 
a next adjacent frame 12. 
The face 22, within the periphery of the groove 24, is provided with means 
28 for anchoring the membrane 14. These means include a recessed area 30 
having projecting therefrom generally pointed upstanding ribs 32. 
It will be readily apparent that there is nothing to hold the membrane 14 
in position relative to a frame 12 during the assembly of the cell 10. 
Furthermore, there is a problem obtaining the proper membrane clamping 
pressure and the proper sealing pressure at the same time. It will be 
apparent that the resilient sealing ring 26 must project out of the groove 
24 and be deformed by engagement by the surface 20 of the next adjacent 
frame 12. A certain pressure engagement is required to assure the seal. 
On the other hand, it will be seen that the ribs 32 must project at least 
to the surface of the face 22 in order that the periphery of the membrane 
14 may be clamped against the ribs 32 by the face 20 of the next adjacent 
frame. However, if the ribs 32 project too high improper engagement and 
deformation of the sealing ring 26 will occur. On the other hand, if the 
ribs 32 are not of sufficient height, when a good seal is made between two 
adjacent frames and the sealing ring 26, insufficient pressure engagement 
of the membrane 14 may occur to prevent displacement of the membrane 
within the completed cell. 
This invention relates to an arrangement which will provide positive 
anchoring of the membrane relative to the frame before the frame and 
membrane are assembled with others in the construction of the cell while 
at the same time providing for an assurance of a proper seal between 
adjacent frames and the proper clamping of the membrane in the constructed 
cell. Accordingly, there is provided a modified frame which is generally 
identified by the numeral 34. The frame 34, with the exception of the 
mounting of the membrane 14, will be identical to the frame 12. The 
underside of the frame 34, as viewed in FIG. 3, presents a planar face 36. 
The periphery of the frame 34 also has a face 38 which corresponds to the 
face 22 of the frame 12. The outer peripheral protion of the face 38 is 
provided with a groove 40 in which there is seated a resilient sealing 
ring 42. The purpose of the sealing ring 42 is to form a seal between the 
face 38 and a face 36 of a next adjacent frame 34. 
In accordance with the invention, inwardly of the groove 40 are means for 
anchoring the membrane 14, the means being generally identified by the 
numeral 44. The anchoring means 44 includes a groove 46 in the face 38, 
the groove preferably being of a dovetailed cross section. Associated with 
the groove 46 is a second resilient sealing ring 48 which may be of a 
slightly smaller diameter than the sealing ring 42. 
In forming the cell 10, each membrane 14 is anchored relative to its frame 
34 by aligning the membrane 14 with the frame 34, and then inserting the 
sealing ring 48. The sealing ring 48, when installed in the manner shown 
in FIG. 3, sufficiently grips the membrane 14 to interlock the membrane 14 
with the frame 34 and permits the handling of the assembled membrane and 
frame without displacement of the membrane. 
After the required number of membranes and frames have been assembled, then 
the membrane-frame assemblies may be assembled to form the cell 10 without 
any worry of displacement of the membranes relative to the individual 
frames. 
With reference to FIG. 4, it will be seen that when two frames 34 are 
assembled, the surface 36 of a next upper or adjacent frame 34 
compressively engages the sealing rings 42 and 48. The sealing ring 42 
forms an ultimate seal against the escape of liquid from between the two 
adjacent frames 34. The sealing ring 48 is further squeezed out within the 
groove 46 so as to more positively clamp the membrane 14 to its respective 
frame 44. At the same time, the sealing ring 48 forms a seal with the 
surface 36 of the next adjacent frame 34. Thus the sealing ring 48 serves 
the dual purpose of tightly clamping the membrane 14 to the frame 34 and 
forming an initial liquid tight seal between two adjacent frames 34. 
Although only a preferred embodiment of the membrane and frame assembly has 
been specifically illustrated and described herein, it is to be understood 
that minor variations may be made therein without departing from the 
spirit and scope of the invention as defined by the appended claims.