Electrolytic cell for a disinfection device

An electrolytic cell of a liquid disinfection device has a housing with an inlet and outlet, and electrodes arranged in transverse planes and surrounding a central supporting element through which electrical leads can be provided. The electrodes can be concentric annular electrodes supported on radial supports, or can be unitary, being punched from sheets with gaps and webs between them.

DESCRIPTION 
This invention relates to an electrolytic cell for a disinfection device 
for disinfecting liquids, in particular water. 
In one device of this type, which is disclosed in German Laid-Open Patent 
Specification No. 2,757,854, electrodes are in planes and are in the form 
of rods, the ends of which are fixed in the walls of a housing. It is an 
object of this invention to provide a disinfection device which is easier 
to construct and more efficient in use. 
According to the present invention there is provided an electrolytic cell 
for a liquid disinfection device comprising a housing having ends, an 
inlet adjacent or at one end and an outlet adjacent or at the other end, a 
plurality of electrodes arranged in planes which are transverse of the 
housing and a central element supporting and surrounded by the electrodes.

In the embodiment of disinfection device shown in FIGS. 1 to 3, a housing 
23 is of cylindrical shape with its upper and lower ends closed by means 
of a base 24 and a cover 25. A circular support column 27 of an insulating 
material is located in the centre of the cylinder. As can best be seen 
from FIG. 3, this column has, on its outer surface rectangular 
longitudinal slots 28-31 which are mutually offset in the peripheral 
direction by 90.degree.. These slots each have a narrowed radially 
interior zone 32, 33. An inlet connection 26 for connection to an inlet 
conduit is provided above the base of the housing and an outlet connection 
34 for connection to an outlet conduit is provided at the upper end of the 
housing. A screen-type flow equaliser 35 is located above the inlet 
connection 26. A stop ring 36 is provided on the inner wall of the housing 
at the height of the lower end of the slots 28 to 31 (see FIG. 2)and above 
the equaliser 35. To assemble this embodiment of disinfection device, 
spacers 38, 39 and 44, 45 are arranged radially in the manner shown in 
FIG. 3, on the stop ring and on the lower ends such as 37, FIG. 3, of the 
longitudinal slots 28-31. The spacers have plane lower and upper seating 
surfaces and at their upper edges a plurality of equidistantly spaced 
recesses 40, 41 which serve to receive electrodes 42, 43 of annular shape. 
The spacers are of two types, conductive spacers 38, 39 and non-conductive 
spacers 44, 45. The spacers are arranged in four planes each including the 
axis of column 27 and spaced 90.degree. from each other. They are also 
arranged in radial planes, in each of which are two conductive spacers, on 
one diameter, and two non-conductive spacers on the other diameter. In 
adjacent radial planes the conductive and non-conductive spacers are 
angular offset from one another. Thus, in each of the planes including the 
axis, conductive and non-conductive spacers alternate. The ends of the 
spacers which are in the slots 28 to 31 are designed in such a way as to 
contact, with their ends, the narrowed zones 32, 33. The conductive 
spacers 38, 39 are each connected to electrical leads 46, 47 passed 
through the slots 28-31. The electric leads pass upwards through the slots 
and out through the cover part 25. The conductive spacers are, like the 
leads, preferably made of titanium. The spacers have such a shape that the 
recesses 40, 41 for receiving the electrodes are mutually offset in a 
radial sense in successive radial planes in the manner which can be seen 
from FIG. 2, so that that electrode rings 42, 43 are offset from the rings 
in adjacent planes and the outermost electrode ring of every second plane 
is in tight contact with the outer wall of the housing 23. This has the 
result that all the liquid flowing through between two electrodes has to 
change direction and is made turbulent. This embodiment is a disinfection 
device which can be assembled in a particularly simple manner and is 
nevertheless highly effective. 
The structure of the housing and of the support column 27 in the embodiment 
shown in FIG. 4 is the same as in the first embodiment shown in FIGS. 1 to 
3 and like parts are indicated with like reference numerals. In this 
embodiment, in place of the annular electrode rods 42, 43 there are 
electrode rods 48, 49 in the shape of open circular rings, that is to say 
their ends are not welded together. One of the spacers 52, is formed as an 
elongate rectangular bar and has a plurality of equidistantly spaced bores 
53 into which the ends 50, 51 of the electrode rods are pressed in the 
manner which can be seen from FIG. 4. The other spacers are the same as 
those of the preceding embodiment. This achieves simultaneously an 
equidistant arrangement of electrodes and an electrical connection of the 
latter to the electric leads, and welding of the electrode rods, which are 
bent into the open circular rings is superfluous. 
The embodiment shown in FIG. 5 in turn differs from that shown in FIGS. 1 
to 3 only as to the shape of the electrodes. In place of the individual 
annular electrode rods held in desired spaced relation by means of 
spacers, the electrodes 54 and 55 of the successive planes are in this 
embodiment produced by punching from metal sheets. Each electrode plane is 
designed in such a way that is has concentric electrode segments such as 
59, 60, with vacant zones 61 punched out between them while there are four 
radial webs such as 56, 57, 58 which are each mutually offset by 
90.degree. in the peripheral direction and which are also provided as a 
result of the punching operation. The radial webs are designed in such a 
way that they each have a zone 62 resting on an outer spacer at the wall 
of the housing and a nose 63 engaging in a respective one of the 
longitudinal slots 28, 29, 30, 31, for connection to the electrical lead. 
FIG. 5 shows, in the left-hand half an electrode plane which is offset by 
one plane relative to the electrode plane shown in the right-hand half and 
it can be seen from the Figure that the electrode segments in successive 
electrode planes are each offset in the radial direction from one another 
so that each electrode segment is arranged above a punched-out zone in the 
plane beneath. In this way, good turbulence is achieved as in the two 
embodiments described above. On assembly, the lowest electrode plane is 
placed on a stop ring 36, and the succeeding electrode planes are then 
arranged one above the other with, in each case, the mutually offset 
electrode segments and punched-out zones and with simple spacers in 
between. A connection to the voltage supply can be made by means of the 
leads 46, 47 passing out through the cover 25 as in the first embodiment. 
The embodiment shown in FIG. 6 also has a housing 23 with a base part 24 
and a cover part 25 as well as an inlet connection 26 and an outlet 
connection 34. In the direction of flow and above the inlet connection 26, 
there is again a flow equaliser 35, the outside of which rests on a stop 
ring 36a and the centre of which rests on a shoulder on a support column 
27. At a distance above the flow equaliser 35, a stop ring 36 is provided 
on which, as in the embodiment described with reference to FIGS. 1 to 3, 
non-conductive spacers 44, 45 are located which are mutually offset by 
90.degree. in the peripheral direction. There is, however, only a single 
set of such spacers. The electrodes used in this embodiment are a 
plurality of cylindrical springs which have different radii and which are 
arranged concentrically around the support column 27. The innermost 
cylindrical spring 67 has a diameter such that it is located tightly round 
the support column 27, whilst the diameter of the outermost cylindrical 
spring 65 is such that it is in close contact with the wall of the housing 
23. The individual springs are each inserted into the housing in such a 
rotational position that as the section shown in FIG. 6 demonstrates the 
turns of two adjacent springs 65, 66 are mutually offset by half a pitch 
in the longitudinal sense of the device. This has the result that the 
liquid flowing through zones between electrodes is then diverted and that 
good turbulence is achieved. 
In the embodiment shown in FIG. 6, the outlet connection is located below 
the uppermost turns of the cylindrical springs, these uppermost turns 
being connected to electrical leads 46, 47, for example by welding. This 
embodiment has the advantage of a particularly simple and cost-saving 
construction, the voltage connection can be made in a very simple manner 
when the cover part 25 is removed. 
In the embodiments described above, a cylindrical housing with electrode 
planes having a circular cross-section was used in each case. In 
principle, the housing can also have a rectangular or square shape, it 
being possible to provide a support column and a stop ring in the same 
manner. The individual electrode rods of the electrode planes, or, in the 
case of punching, the electrode segments, then likewise have a rectangular 
or square shape adapted to the internal cross-sectional shape of the 
housing. Furthermore, in place of the cylindrical springs, helical springs 
or helical coils with a rectangular or square run can be used as in the 
embodiment shown in FIG. 6. The making of the contacts and the mutual 
offsetting of the electrode zones in successive planes are effected in the 
same way as in the cylindrical illustrative embodiments described above. 
In place of the electrode designs described above, the individual planes 
can also be formed of porous conductive metal. Thus, a sintered material 
can be used for this purpose, for instance one which is formed by dumping 
small metal beads, preferably of titanium having a diameter in a range 
from preferably about 0.5 to about 3 mm, in a layer of a thickness of 
about 2 to 3 bead diameters and metallically joining them at the contact 
points. The cross-section of the sintered material thus formed is adapted 
to the cross-section of the housing and the layers of sintered material 
are arranged one above the other in the direction of flow, for example by 
means of spacers. Electrical contact can be made in the illustrative 
embodiments described above. In place of the sintered material described 
here, other porous metal layers can also be used, it being necessary for 
the porosity to be selected in such a way that, on the one hand, a large 
contact area and, on the other hand, adequate flow through the layers are 
achieved. 
In another embodiment of the invention, the electrode material can be 
formed from non-rolled expanded metal. This is produced in the 
conventional manner from a sheet metal panel of an appropriate conductive 
electrode material by punching and subsequent elongation. A very large 
active area is achieved with this electrode form and also by the 
three-dimensional shape produced upon elongation. As a result of this 
three-dimensional shape, electrode surfaces which are inclined relative to 
the horizontal are produced, and this has the consequence that a very 
favourable removal of gas bubbles from the flow passing through is 
achieved. On assembly, the individual electrode sheets, separated from one 
another by spacers, can be inserted into the housing, their external shape 
corresponding to the cross-section of the housing. The electrical supply 
can be effected as in the illustrative embodiments described above. 
Preferably, the sheets of successive electrodes are in this case each 
arranged in such a way that the directions of elongation are mutually 
offset by 180.degree. so that those zones of one electrode plane, which 
are the electrode surface zones, are inclined to the horizontal in the 
opposite direction to those of the next plane. This means that the flow 
from one plane to the next is always directed at the surface zones, and a 
large contact effect and good turbulence of the liquid are achieved. 
In embodiments with electrode planes of expanded metal or sintered 
material, the electrode planes can fully correspond to the cross-section 
of the housing and are self-supporting due to their stability, so that 
stop rings 36, provided on the wall of the housing, and spacers are 
sufficient to support them and, if desired, the support column 27 can be 
omitted if the electrical supply is effected in some other way. Even here, 
however, the use of the support column 27 makes a particularly favourable 
connection via the electrical leads 46, 47 possible. 
In the embodiments described above, the inlet connection 26 and the outlet 
connection 34 are provided in the lower part and upper part of the lateral 
wall. However, the inlet can be provided at the lower base 24 and the 
outlet 34 in the cover part 25 in such a way that these are mutually 
aligned in the direction of flow. In this way, the electrolysis cell can 
be built very simply into an existing pipe.