Bonded busbar for diaphragm cell cathode

In a sidewall-enclosed electrolytic cell, such as for the electrolysis of brine to form chloralkali product, the cell can have at least one cathode sidewall. There is now provided an at least substantially wall-sized, planar busbar that is interface bonded to the cathode sidewall. The interface bonded, wall-sized busbar plus sidewall thereby at least substantially serve as a wall unit for the electrolytic cell. The wall-sized busbar has at least one internal passageway therethrough for the circulation of cooling fluid. Where the bonded busbar is connected by a jumper switch for current connection, the cooling passageway of the busbar may connect at the location of the jumper switch.

BACKGROUND OF THE INVENTION 
In the manufacture of chlor-alkali diaphragm cells, there have been 
developed cells which operate at high current capacities with 
correspondingly high production capacities. Typically, chlor-alkali 
diaphragm cells may now operate at current capacities of upwards to about 
200,000 amperes, while maintaining desirable operating efficiencies. One 
such cell which has been developed for this more efficient operation 
comprises a novel cathode busbar structure. As shown in the U.S. Pat. Nos. 
3,859,196 and 3,904,504 this novel cathode busbar structure comprises at 
least one lead-in busbar and a plurality of busbar strips which have 
different relative dimensions. This structure is attached to a sidewall of 
the cell whereby the sidewall plus busbar structure provides an at least 
partially cathode-walled enclosure. 
Such chlor-alkali diaphragm cells which have been developed to operate at 
high current capacities can also require a high amperage switch apparatus. 
A suitable such apparatus has been disclosed in U.S. Pat. No. 3,778,680. 
Therein there is shown a switch apparatus particularly for high amperage 
electrical switching, which apparatus is resiliently mounted and has 
fluid-cooled terminals. 
It would be desirable to combine the features of these developments to 
readily accommodate high amperage switch apparatus with a cathode busbar 
structure of a cathode-walled enclosure. 
SUMMARY OF THE INVENTION 
It has now been found possible to provide a most efficient cathode sidewall 
busbar structure. The structure is economically monolithic and unitary. 
The structure can be desirably compatible with present day high amperage 
switch apparatus. Such compatibility includes linkage of the switch 
apparatus cooling means with cooling means for the sidewall busbar. 
In one broad aspect the invention relates to an electrolytic cell wherein 
the cell comprises a walled enclosure with there being at least one 
cathode sidewall for the enclosure, such cell having a cover over, and a 
cell bottom beneath, the walled enclosure, and with there being means for 
introducing current from outside the cell to a cathode sidewall through a 
busbar. In this context, the invention provides the improvement comprising 
a cathode busbar structure external to the cell, which structure has an at 
least substantially wall-sized sidewall busbar that is interface bonded to 
the cathode sidewall, whereby the cathode sidewall plus interface bonded 
sidewall busbar combine together to form at least substantially a wall 
unit for such cell, with the sidewall busbar having internal passageways 
for the circulation of cooling fluid therethrough. 
In another aspect the invention is directed to a novel busbar for interface 
bonding to a cathode sidewall of an electrolytic diaphragm cell.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
The invention relates generally to electrolytic cells suited for the 
electrolysis of aqueous alkali metal chloride solutions. The cells may be 
used for the production of chlorine, chlorates, chlorites, hydrochloric 
acid, caustic, hydrogen and related chemicals. For the sidewall of the 
cathode-walled enclosure it has been typical to use a conductive metal 
which has desirable strength and structural properties. Most always, the 
wall will be made of steel, e.g., cold-rolled, low carbon steel. For the 
cathode busbar structure the useful metals are those which are highly 
electrically conductive. Most always this metal will be copper, but there 
may also be used aluminum. 
Referring now more particularly to FIG. 1, a cell shown generally at 1 has 
a cover 2 and four sidewalls 3. The sidewall 3 in the foreground is 
positioned behind a sidewall busbar 4. The sidewall busbar 4 is connected 
by intercell connectors 5, only some of which are shown, to an adjacent 
cell, not shown. More particularly, each intercell connector 5 is 
connected to a spacer 7 which is fitted over a post 8. The connector 5 on 
the one end is secured to the post 8, and on the opposite end is secured 
by nuts 9 to the base of an adjacent cell, not shown. 
These intercell connectors 5 are positioned across almost the complete 
length of the sidewall busbar 4, at the bottom. As is more particularly 
depicted in the figure, this sidewall busbar 4 can be a unitary, 
monolithic and planar busbar 4 that is, for the particular cell 1 of the 
figure, as high as the cell sidewall 3 and can be longer than the sidewall 
3 to which it is bonded. The busbar 4 may thus be actually larger than the 
sidewall 3. But, in essence, the sidewall busbar 4 and its adjacent 
sidewall 3 together form one wall of the cell 1. The extra length of the 
sidewall busbar 4, extending beyond the intercell connectors 5, forms a 
sidewall busbar extension 11. To this sidewall busbar extension 11 there 
are attached cathode jumper switches or connectors 12. Each jumper 
connector 12 comprises a tubular conduit 13 and a lug 14 extending into 
connection with the sidewall busbar 4 at the sidewall busbar extension 11. 
Further, this sidewall busbar 4 contains a cooling conduit passageway 15, 
extending in a generally loop configuration and shown in phantom. 
Referring then to FIG. 2, there is shown the interface bonded structure of 
sidewall 3 and sidewall busbar 4. This bonded structure extends the full 
length from an edge of the cell cover 2 downwardly to a cell bottom 16. 
Connecting to the sidewall 3 and sidewall busbar 4 through a post 8 and 
spacer 7 is an intercell connector, not shown. Extending into the sidewall 
busbar 4 is a cooling conduit 15, the direction of the flow of coolant to 
and from the conduit 15 being shown by the arrows. 
Referring then to FIG. 3, a sidewall busbar extension 11 extends beyond a 
busbar 4. Connecting to this sidewall busbar extension 11 are the cathode 
jumper connector lugs 14. As shown more particularly in this figure, a 
pair of jumper connector lugs 14 are secured to the sidewall busbar 
extension 11 by a nut 17 and bolt 18 which connect through an aperture 22 
in the sidewall extension 11. There is then formed in the busbar 4 and 
sidewall busbar extension 11 a conduit passageway 15, generally concentric 
in cross section. Fluid cooling media, usually water, can be fed into this 
conduit passageway 15 by a coolant inlet feeder hose 20. After circulating 
in the busbar 4 and extension 11, coolant in the passageway 15 can flow 
out of the sidewall extension 11 through a coolant exit return hose 21. 
Cooling fluid can be supplied to the inlet feeder hose 20 from a cell room 
source, not shown, external to the cell. 
By such means cooling fluid can be provided to the cathode busbar 4 when an 
adjacent electrolytic cell is jumpered. It is to be understood however 
that cooling means can be used during routine cell operation to cool the 
cathode busbar 4, although it is normally needed only during jumpering of 
the cell when the entire electrical current flows through the lugs 14 and 
busbar extension 11 to the cathode busbar 4. 
In assembly, the cathode busbar 4, being typically a copper busbar 4, can 
be interface bonded to the cathode sidewall 3 such as by explosion 
bonding, brazing or roll bonding. Where the cathode busbar 4 is copper and 
the cathode sidewall 3 is steel it is preferred to use explosion bonding 
or brazing. Even though the sidewall busbar 4 can be a unitary, monolithic 
planar busbar 4, which even extends in length beyond the length of the 
sidewall 3 and which is usually of uniform thickness for its total length 
including the length beyond the sidewall 3, such busbar 4 can nevertheless 
be desirably interface bonded to the sidewall 3. Such bonding can provide 
for an integral electrical unit achieving desirable efficiency of cathode 
operation. It is also to be understood that the busbar extension 11 may be 
an attachment to the sidewall busbar 4. Such attachment can be by 
metallurgical means, e.g., welding, or by mechanical means such as 
bolting. 
It is to be understood that the intercell connectors 5 including the 
spacers 7, and posts 8, will be made of any material of construction 
usually utilized for such items, e.g., copper. Furthermore, the cathode 
jumper connectors 12 will have electrically insulating tubular conduits 
13, as well as lugs 14 as conventionally employed for such electrolytic 
cells, e.g., copper lugs 14. For cooling, the sidewall busbar cooling 
conduit passageway 15 may take any desired form for supplying cooling to 
the sidewall busbar 4. Usually such passageway 15 will be fashioned in the 
form of a loop originating in and exiting from, the sidewall busbar 
extension 11. Where the supply of cooling liquid is to be particularly 
utilized during jumpering, such a loop may extend partly, e.g., 
substantially halfway, along the length of the sidewall busbar 4, as more 
particularly depicted in FIG. 1. In any event, for most efficient cooling 
of the sidewall busbar 4 it is always contemplated that cooling fluid will 
be provided to and removed from the busbar 4 in the manner as shown in 
FIG. 3. This sidewall busbar passageway 15 is preferably obtained by rifle 
drilling, i.e., deep and narrow passage drilling performed with a lathe.