Note: Descriptions are shown in the official language in which they were submitted.
1053606
This invention relates to welding, brazing and the
like, utilising hxdrogen and oxygen, and extends to such
applications as oxy-welding, oxy-cutting, atomic welding,
and welding ox cutting in co~ination with electric arc tech-
niques. The invention also provides for the generation of
hydrogen and oxygen for the a~ovementioned applications in
com~ination t~ere~ith or separatel~.
A most important application of the invention is
atomic weld~ng utilising the properties of atomic oxygen in
co~bination with atomic hydrogen (for welding) or atomic oxy-
gen separately (for cutting). This particular application
of the invention is based, among other things, on the appre-
ciation that considerable energy is associated with the dis-
sociation of molecular oxygen into atomic oxygen by passing
this gas through an arc, and that this property can be use-
fully employed to generate temperatures even higher than
those previously attainable with, for example, an atomic
hydrogen flame. The significance of the energy which can be
obtained in this way can be appreciated from the following
reactions that take place, and the heat energies associated
therewith, when hydrogen and oxygen are both passed through
an electric arc. Thus:
H2~ H + H absorbl~ng 101,000 cal. per gram mole
2- > ~ O absorbing 117,000 cal. per gram mole
total 218,000 cal. per gram mole
On recombination of these atoms this energy is re-
leased as heat through a number of complex chemical reactions
and results in an extremely high flame temperature.
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1o536o6
Previously it would not haYe been considered possible to
pract~call~ pas~ ox~gen or a mixture of oxygen and hydrogen
together through an arc due to the highly explosive or in-
flammable nature o~ such gases. However in accoxdance with
the concepts of the present invention this is indeed both
possible and practical and, as mentioned above, enables the
realisation of much higher welding or cutting temperatures
than hitherto obtainable by known practical means.
One of the objects of the present invention is to
provide a method and apparatus whereby hydrogen and oxygen
can be generated quickly and conveniently for immediate use
for welding, etc., without many of the disadvantages associ-
ated with conventional gas welding practice. For example,
the practice of employing cylinders (or "bottles")of gas,
usually oxygen and acetylene can have significant disadvan-
tages, particularly for users working remote from a supply
depot and for whom there might be an appreciable delay be-
tween the placing of an order for a delivery of gas and the
actual delivery. For such users, in order to ensure an ade-
quate supply of gas when a particular job demands it, it isoften necessary to order fresh supplies in advance, even be-
fore the supply on hand is fully used, or else risk running
out of gas before a job is completed. Since bottles of gas
are generally delivered on a strictly exchange basis - in
that a used bottle must be returned in exchange for arefilled
bottle - the practice can mean a significant waste, as far as
the user is concerned, if bottles containing useful amounts
of unused gas have to be returned to the supplier.
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~05360~i
The practice of using bottled gas also has associ-
ated with it a large num~er of other problems such as the
possibility of gas leaking from bottles, possibility of in-
dustrial disputes which can result in severe delays in deli-
very and in supply shorta~es, liaBilities, high purchase and
storage costs, freight charges, and so on.
To illustrate some of the conditions which the con-
sumer o~ bottle gas must put up with, listed below is a sum-
mary of the "conditions o~ sale" which apply to the sale and
distribution of bottled gas.
(a) The cylinder remains the sole property of the sup-
plier, which reta~ns the right to exercise at any time its
proprietary po~ers in its discretion.
~ b) All cylinders and contents are forwarded at the
expense and risk offfie customers.
(c~ It is the responsibility of the customers to pro-
vide adequate labour for the loading and unloading of all
cylinders at the premises.
(d) Cylinders are to be returned to the supplier as
soon as empty, carriage and freight charges paid.
~ e) A cylinder is not 'returned' until received by the
supplier at its works or warehouse or by its truck and a re-
ceipt on the supplier's form given for the same. No docu-
ment purporting to be a receipt for anys~ch cylinder shall
be valid unless it is the supplier's printed form of receipt
(f) Cylinders are not transferable and must not beused for any purpose other than as containers for the gas
sold by the supplier and must not be delivered or sent for
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~053606
recharging to an~ place other than the supplie~'s gas station.
~ g) The customer agrees not to resell to any person or
Corporation, the gas contents o~ the cylinders or any part
thereo~.
Oh) Customers are held responsible for all loss or dam-
age to cylinders from ~atever cause arising from the time of
delivery until returned to the suppliers. ~Customers are ad-
vised to cover the cylinders by insurance.)
(i) Where a customer has not returned a cylinder in
good order and condition within six months from the date of
delivery, the supplier may, at its option, charge the customer
with an amount not exceeding the agreed value of the cylinder
and the demurrage due in respect thereof, and such amount is
payable by the customer as liquidated damages for the deten-
tion of the cylinder. Notwithstanding thepayment of such
amount in respect of any cylinder, it remains the property of
the suppliers and the right of the suppliers to recover pos-
session thereof is not affected in any way.
(j) No allo~ance is made on any residual gas returned
in the cylinders.
(k) And many other conditions varying in the different
countries in the world.
Another disadvantage, which is associated with oxy/
hydrogen welding, arises due to the marked ~ility of hydrogen
--to be absorbed by most-metals. Thus when welding steel, for
example, great care must be taken to ensure that excess hydro-
gen is not present otherwise it will be absorbed in the metal
to cause loss of strength and brittleness. On the other
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~.053~;06
hand, an excess o~ o~y~en would cause burning of the ~etal
and should thus e~ually be avoided. It is most important
therefore that with oxy~hydrogen ~elding the mixture at the
burner be adjusted to produce a neutral ~lame, that is, one
in whic~ there is ne~ther excess hydrogen nor excess oxygen.
In practice it is most difficult to maintain (and virtually
impossible to ~udge by flame colour) a neutral ~lame, and
for that reason oxy/hydrogen welding is not widely used des-
pite the inherent advantages of lo~ cost and high heat value
offered by hydrogen as a fuel.
These and other disadvantages can be overcome to a
significant extent by the present invention whereby hydrogen
and oxygen f~el are generated simultaneously by electrolysis
in an electrolytic cell and allowed to freely mix therein to
form a stoichiometric mixture that will burn with a neutral
flame. The fuel gas can be generated where and whenever re-
quired thereby eliminating the need for storage of bottles of
gas and reliance on regular deliveries of gas which often
cannot be guaranteed.
The method of the present invention requires no
diaphragms or the like to separate the hydrogen and oxygen
liberated by the electrolysis process and thereby enables
considerable advantages to be realised over conventional
electrolytic production of these gases. Such diaphragms
have normally been regarded as essential for conventional
electrolytic generators in order to separate the two gases
that would otherwise form a highly explosive mixture; however,
it has been found, in accordance ~ith the present invention,
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1053606
that the two gases can be safely, anduse~ull~, produced and
utilised as a m~xture ~or fuel purposes provided that suit-
able safety precautions, such as the employment of a flash-
back arrestox, are taken.. Such safet~ precautions may in-
clude, for example, t~e.emplo~ment of a deyice ~hich removes
electrolyte vapour fro~ the gas and at the same time acts. as
a flash-~ack arrestor. Tn obviating the need for diaphragms
or the like t~e present invention enables the electrodes to
be placed much closer together and avoids the high resistance
associated with diaphragms, which in turn enables a signifi-
cant increase in the rate of gas production for a given size
of apparatus. In short the present invention enables the
manufacture of small si~e equipment that is useful for a
large variety of welding and similar work and that is not
- prohibitively bulky.. for the average situation:.- sométhing
which is impossible with conventional hydrogen/oxygen genera-
ting equipment.
In the development of apparatus from the basic con-
cept of generation of hydrogen and oxygen electrolytically in
a practical manner suitable for large industrial applications
on the one hand, and small domestic applications on the other
hand, a number of factors had to be taken into account, ana- -
~; lysed and weighed one against the other. The following is a
list of some of these factors to illustrate what has been in-
volved.
(a) Endosmotic pressure to be balanced against the
hydrostatic pressure o~ the flu~.d.
(b) Rate of flo~ of electric current in relation to the
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11)53606
area of the electrodes.
(c) The pr~or art problem o~ removing the gases from
anol~te and cathol~te, be~ore diffusion and before the elec-
trolytes are intexmixed.
Cd~ Effects of rapid chan~es in the rate of ~low of
electricit~ throu~h t~e cell.
~e) Ef~ects o~ auxil~ary decomposition within the anode
and cathode sides of the cell.
(f) The choice of the most readily ionised electrolyte
o~ a maximum conductivity.
~) The least possible spacing between anode and cathode
that can be employed.
(h) A design of cell in which previously it was regarded
impossible ~or the H2 and 2 given to become mixed with safety,
which does away with diaphragms-or the like ~hich would in-
crease the internal resistance, in which both hydrogen and
oxygen can be mixed within the cell, and in which cells can be
connected in series, parallel, or parallel and series to suit
requirements.
Ci) The choice of mater~als ~or the electrodes.
(j) The quantity of acids or alkali to be used.
ok) The shapes of cells according to purpose of the
cells, and the application for which they are designed.
~1) The possibility of improvement with permanent or
electro-magnetically induced fields applied to the electro-
lytic cells, to cause controlled separation of a quantity of
the gases generated in the cells.
~n) Ensurin~ effective circulation of electrolyte be-
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105360~;
t~een the electrodes, ~th as l~ttle electrical xesistance as
possible,
Cn~ The possibility of using sodium hydroxide or potas-
sium hydroxide which, in concentratîons from 10~ up to 30%,
has negligible corrosion action on iron or nickel elec-
trodes, apart from producing a solution of good conductivity.
Co~ The use o~ t~e cooling ef~ect by passing of hydrogen
and oxygen gases, for cooling electrolyte in the cell, for
controlling the cell temperature, preferably between 40C to
60C, at which temperature the bonds between hydrogen and
oxygen need a minimum o~ electrical energy to break.
(p) The separation of hydrogen and oxygen from a mixture,
using, pocsibly, a permanent magnetic field, or an electro-
magnetic field which can be controlled to obtain a desired
separation between the hydrogen and oxygen. Based on this
principle, the oxygen could be substantially separated from
the mixture and the hydrogen could be absorbed by, for example,
selected metals, which have high absorption affinity for hydro-
gen ~for example, p~adium which absorbs 900 times more hydro-
gen than its volume). Also, using the principle of the in-
vention, hydrogen and oxygen can be generated in large quanti-
ties with small units and the oxygen could, for example, be
separated and used to supply hospitals, baby rooms, air condi-
tioning systems, or for any other application, when oxygen is
required. Oxygen can, in this way, be generated much faster
and more conveniently than with conventional electrolytic
generating equipment.
C~) The poss~bil~ty of absorbing the hydrogen or oxygen
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1053606
by spec~ally selected mater~als in s~all conta~nexs and
where the a~sor~ed gas can ~e extracted when desired for
~eldin~ or brazing ~here it ~ould be in¢onvenîent or impos-
si~le to do so w~th conventional equi~ment.
~rl Making t~e ~eldin~ operator entirely independent of
any gas suppliers,
Cs) The genesat~on of cheap gas, up to 6 to 7 times
cheaper than normal gas supplîes.
Ct) The design of equipment which gives not only pro-
fessional welders, but handymen, or people who would like to
do welding at ~ome with oxy-welding apparatus, but would do
it only occasionally and could not justify the expense asso-
ciated with conventional gas supplies. Such people cannot
justify paying for bottles of gas for a single welding only
(having to keep the bottles, paying rent for them to keep
them up to two years, to perform the next welding). For
this reason, the welding apparatus made possible by the
present invention is ideal because it produces gases for wel-
d~ng at the time and in the quantity that is needed.
(u) Hydro~en/oxygen ~elding has the advantage that it
does not pollute t~e atmosphere as~does oxy/acetylene welding.
~v~ The desi~n of electrolytic cells which are safe to
- use as well as convenient, which cells may incorporate their
own flash-back arrestors as a safety precaution or an equiv-
- alent means, to prevent the hazards of explosion or fire.
(w) The control of the cur~ent which passes through the
cells, the temperature of the cell, which is a function of
current, the control ~f the separation of the gases, and the
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1053606
remoYal fxom the gases of electrolyte yapouxs~ In this re-
gard t~ere has been des~gned a specîal unit with preferably
conical electrodes, and a flash-back arrestor. The flash
arrestor ma~ be constituted by a pellet of poxous material,
or a long caplllary pipe located between the gas generator
and a burner head. The ~ire hazards associated with a mix-
ture o~ hydrogen and oxygen cannot be over~emphasized and
indeed it is proba~ly mainly because of the recognised dangers
associated therew~th that extreme lengths have been taken to
separate the two gases completely until they reach the burner.
In accordance with the present invention it has heen realised
that, contrary to long standing opinionsj the gases can be
safely mixed together even when being produced and as a re-
sult many desira~le advantages can be realised.
~ x) The provision of one or more safety valves adjusted
to convenient pressure for releasing excessive pressures in
the cell ~for example, greater than 30 p.s.i.) which may re-
sult, for example, i~ a current control mechanism fails. The
safety valves could be attached to an alarm, for example, to
indicate a failure in the current control mechanism or the
cut-off switches, etc.
~ y) Porous material may conveniently be placed in the
burner head, so that backfire through the burner into the
cell cannot occur.
In a preferred embodiment of the present invention,
there is provided a regulating device suitable for use with
an electrolytic cell generating hydrogen and oxygen, the de-
vice comprising an electrolytic chamber, an aqueous electro-
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~053606
lyte contained in sa~d chamber., ~irst and second electrodes
immersed in said aqueous electrolyte, inlet means in sa~d
chamber adapted to permit gaseou~.co~munication between said
electrolytic chamber and a gas output from the electrolytic
cell, said a~ueous electrolyte being displaceable relative to
said first and second electrodes immersed therein such that
an increase in pressure of said gas from the electrolytic cell
will act to displace a portion of said aqueous electrolyte
and proportionatel~ ~ncrease t~e electrolyte resistance be-
tween said pair o~ electrodes.
In a further embodiment of the present invention,
there is provided apparatus for generating a supply of hydro-
gen gas and oxygen gas in proportion to consumption of said
gases comprising
- Ca) an electrolytic cell means for electrolytic
generation of said gases, said cell being
enclosed to entrap said generated gases,
~b) a gas outlet carried by said cell to allow a
portion of said generated gases to discharge
from said.cell,
Cc) a source of electrical po~er connected to said
cell by a suitable circuit, and
Cd) an electrical power regulating means for con-
trolling the amount o~ power to said cell including:
a first chamber having a selected cross-sec-
tional area and an upper and lower inlet,
said upper inlet connected with said gas
outlet of said cell,
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1053606
,a second cham~er.h~Yin~..a selected cxoss~
sect~onal,area at.least one hal~ less
than that of said.first chamber and a
lo~er inlet, said inlet connected to
sa~d lo~er inlet o~ said first chamber
by a suita~le passage,
a ~irst and second inverted conically-shaped
and concentrically aligned resistant
electrode carried in a vertical relation-
. s~ip in said first chamber, said electrodes
connected in said circuit bet~een said
po~er source and saàd cell,
and
a quantity.o~ electrolytic solution carried in
said chambers to partiall~ fill said
chambers and interface wi'th said electrodes ' '
to close said circuit,
wherein an increase in the pressure of said en-
trapped gases depresses the level o~ said electrolytic solu-
tion in said first chamber to cause an increase in resistance
o~ said electrodes thereby reducing the amount of power to said
cell.
In a still ~urther embodiment.o~. the present inven-
; :
::. tion, there is provided an,apparatus for generating a supply
:~:o~ hydrogen and oxygen gases comprising
`(a) an electrolytic cell means for electrolytic
generation of said gases, said cell being en-
:closed to entrap said generated gases,
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1053~06
~b~ a gas outlet carried b~ said cell to allo~
a portion of sa~d generated gases to dis~
charge from said cell,
Cc~ a souxce of electx~cal po~er connected to
sa~d cell b~ a suita~le circuit, and
Cdl an electxical power regulating means inclu-
; ding,
a first chamker having a selected cross-
sectional area and an upper and lower
inlet, sald upper inlet connected to
said outlet of said cell,
a second circular c~amber having a pre-
selected cross-sectional area, said
: area of said second chamber being at
~, least one-half that of said first
chamber, and a lo~er inlet, said inlet
connected to said lower inlet o~ said
first chamber by a passage,
a quantity of electrolytic solution carried
! 20 in said chamber to partially ~ill said
chambers,
~ a quantity of non-conductive liquid having
r a specific gravity less than said
: electrolytic solution carried in said
first chamber above said electrolytic
~ solution,
,à,~ and
a first and second electrode carried by said
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1053606
first chamber in a vertical relation-
shl~.p and extending in~ardly t~erein to
interface w~th sa~d electrolyte solu-
tion, sa~d electrodes connected in said
c~rcu~t between sa~d po~er source and
said cell to close said circuit,
wherein a su~fic~ent ~ncrease in pressure of said
; entrapped gases depresses the level o~ sa~d non-conductive
liquid and said electrolyte to interface said upper electrode
: lO ~ith said non-conductive materlal ~hereby said circuit is
opened.
` In a still further embodiment of the ~esent inven-
`! tion, there is provided a system for generating a supply of
hydrogen gas and oxygen gas in proportion to a consumption
of said gases and protecting said system comprising:
a) an electrolytic cell means for electrolytically
generatin~ said gases; said cell being enclosed
to entrap said generated gases,
~b) a source o~ electrical power connected to said
. 20 cell by a suitable circuit,
and
(c) a gas outlet means to allo~ a.discharge of said
` gases and protect saîd cell ~rom a flash-back
and provide regulation of said gas generation
- further including,
a ~irst vertical chamber having a top inlet
~` connected with said cell and a bottom
. ~ outlet
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~053606
a second vertical cham~er hav~ng a substan-
tially greater cross.sectional area than
sa~d first c~am~er, said second chamber
hav~n~ a top outlet for dischaxging said
gas to a gas consumption means, and a
~irst and second bottom inlet, said first
inlet connected to said bottom inlet of
said first chamber by a horizontal passage,
a t~ird vertical chamber having a bottom inlet
q 10 connected to said second bottom inlet of
ii said second chamber, said third chamber
: having a cross-sectional area greater than
said first chamber and less than said
: second chamber,
a quantity o~ electrolytic solution carried in
said first, second and third chamber to
~- partîally fill said chambers,
a first and second inverted, conically-shaped
. ~ resistant electrodes concentrically aligned
; 20 and carried by said second chamber in a
. vertical relationship, said electrodes
connected in said circuit to close said
circuit when in contact with said electrolyte,
x ~ w~erein an increase in pressure in said second
- chamber depresses the level of said electrolyte to decrease
"`~ the generation of said gases by increasing resistance in said
circuit by increasing exposed portions of said resistant elec-
trodes, said eleatrolyte acting as a protective barrier be-
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~ 053606
tween sa~d.gas consumption.means and said cell.
~ n a still.~uxthe~ emBodiment of the ~resent.inven-
tion thexe is provided an apparatus for the generation of
hydrogen and ox~gen and utilization of same for welding,
brasi,ng or t~e like., said apparatus comprising at least one
electrol~t~c cham~er having electrodes immersed in an aqueous
electrolyte contained in said chamber, a pressure sensitive
regulating de~ice containing an aqueous electrolyte, at least
. one pai.r o~ electrodes immersed in the aqueous electrolyte
contained in said regulating device and connected in series
with said electrodes contained in said at least one electro-
lytic chamber, a passageway connecting said pressure sensitive
,,
regulating device with said at least one electrolytic chamber,
said aqueous electrolyte in said pressure sensitive regulating
device being displaceable relative to said pair ofelectrodes
~:. immersed therein so as to proportionately increase the elec- ' ,
~ trolyte resistance between.said pair of electrodes and conse- ,
,~ ~uently reduce the electric current passing in series between ---
.,~ . said pair of electrodes and said electrodes in said at least ....
one electrolytic chamber in accordance with an incxease in
pressure of sa~d gases, an outlet to said regulating device,
means passing said gaseous mixture from said outlet through a
flash-back arresting means to a burner nozzle, and a pair of
electrodes arranged.downstream of said burner nozzle in the
~` path of said gases therefrom, said electrodes being connect-
~; able to a source of electrical arc energy for causing dissoci-
ation of said gaseous mixture into atomic h~drogen and atomic
;~ ox~gen.
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1053606
In a st~ll further embod~ment o~ the present inven-
tion, there is- provided a method of ox~hydrogen ~elding,
brazing or the like, character~zed by electrolytically gener-
ating a mixture of hy.~xo~en and ox~gen in substantially stoi-
chiometric proport~ons by passing an electric current between
electrodes immersed ~n an aqueous electrolyte contained in at
least one electrolytic chamber, passing the mixture of hydro-
gen and oxygen from sa~d at least one chamber through an
aqueous electrolyte contained in a pressure-sensitive regula-
ting device having at least one pair of electrodes connected
electrically -in series with said electrodes in said at least
one electrolytic chamber, which electrolyte in said regula-
ting device is displaceable as a result of pressure of said
mixture of hydrogen and oxygen to proportionately increase
the electrolyte resistance between said pair of electrodes
and consequently reduce the electric current passing between
said pair of electrodes in said regulating device and said
electrodes in said at least one electrolytic chamber in
accordance with an increase in pressure therein, passing said
gaseous mixture through flash-back arresting means and thence
through a burner nozzle, producing an arc between electrodes
arranged downstream of said burner nozzle and in the path of
said gases so as to produce disassociation of said gases into
atomic hydrogen and atomic oxygen, and burning said hydrogen
and oxygen to produce a flame, the temperature of the flame
exceeding the normal temperature of combustion of molecular
hydrogen and oxygen.
. ~
In summar~, the present invention contemplates, as
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1053606
an i~portant ~eature t~ereof, a universal welding apparatus
capable o~ being used to perform di~ferent t~pes of welding
operat~ons based on t~e ut~lisation o~ hydrogen and oxygen,
making full use o~ t~e advantages which can thereby be real-
ised, and e~uipment wh~ch can be made small and portable com-
pared w~th existin~ apparatus- such as that presently used for
gas w~lding using bulky bottled hydrogen. To generate the
fuel, in accord~nce wit~ t~e invention a small compact elec-
trolytic cell is made possi~le in which the only ~aw material
which has to be replenîshed from time to time is water and
whic~ can be used whenever a source of electrical energy is
available to supply the necessary amount of hydrogen or hydro-
' gen and oxygen mixture for performing atomic welding or hydro-
i gen/oxygen flame welding. In its simplest form, the gas gen-
erating apparatus of the present invention comprises an elec-
3 trolytic cell adapted to be connected to an energy source,
,~ optionally through a step down transformer and rectifier, and
having means for connection to a burner, preferably through a
flashback arrestor as a safety precaution.
- The apparatus ~ay be combined with a transformer as
1; a æingle co~pact unit and for convenience the trans~ormer may
be provided with several windings to enable it to be used for
auxiliary purposes such as battery charging, electroplating,
`1 . '
arc welding or to provide an arc for atomic welding.
It has been found that a single electrolytic cell
operating without diaphragms at several hundred amps will
generate hydrogen and oxygen at a reasonable rate for small
welding and brazing work but for larger work ~for example,
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1053606
the ~eldin~ of 10 m~ steel plate) the required ampexage be-
comes excess~ve Ct~p~cally o~ t~e ordex of 900A or more) when
considering the s~ze of conductors and transformer and the
problem of heat generat~on. Accordingly, in one aspect of
the invent~on these pro~le~s can ~e sign~icantly reduced by
arranging a plurality of cells in series and using a much
smaller current to obtain the same effective gas output. In
e~fect the capacity of a ser~es o~ cells for a gi~en current
input is that of a single cell multiplied by the number of
.~
cells. Alternatively the current requirement is reduced by
a factor equal to the number of cells - for a given rate of
i gas production.
i Even so a large number o~ separate cells can be
^excessively bulky for portable applica-tions and in a further
aspect of thq invention, theréfore, the bulk can be greatly
reduced by arranging the cells as a s`ingle unit in which a
number of electrodes, effectively in series, are arranged
., , ~
~ adjacent each other in a common electrolytic chamber, the
,;
chamber being provided with a gas collection space and an
outlet for connection to, for example, gas burner means.
Furthermore, only the end electrodes need be connecte~ to an
~1 external source of electrical energy and the arrangement as
a ~hole can be made extremely efficient and compact. Addi-
tionally the need for a transformer for most applications
can be eliminated by such an ar~angement so that the appar-
~ atus can be designed to be electrically connected directly
-~ to a main electrical supply, through a bridge rectifier if
~ desired. By eliminating the need for a transformer, the
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gas generat~ng e~uip~,ient a~ a ~hole.can be made surprisingly
compact, to be well.su~ted ~or small domestic xequirements
as well as heaY~ ~ndustr~al xequirements.
. In anothex àmpoxtant aspect.o~ t~Q ainYention~ there
is pxov~ded a sa~ety device.~hich.monitors the.pressure of
the hydrogen and o~ygen being generated and regulates the
' current ~lo~ing t~rough the cell~s) to increase or decrease
; the rate o~ gas product~on depending on the pressure. In one
form the device comprises a ~hamber containing two electrodes,
at least one o~ which is conical, arranged in the chamber
. (which normally contains a conductive liquid) and the elec-
trodes being connectable in series with one or more electro-
lytic cells used for oxygen/hydrogen productioh.
, The pressure responsive, current regulating device
can be designed as an integral part of the electrolytic
cell(s) or can be used as an attachment connectable extern-
'~ ally and in series with the gas generating cell(s). The~, device can also be designed to combine the functions of a
current regulating device and a flash-back arrestor, the
latter function ensuring that a flame at the,burn-er does not
,~ accidentally pass back through the hose lines to the highly .
3 explosive mixture in the gas generating cell(s). The device -
'. may.incorporate a total current cut-out feature or may be
~ ~ .
used in combination with a cut-out device which fully inter-
.~ . rupts the supply of electràcal power should the pressure in
the cell(s) accidentally exceed a maximum safe value. The
current regulating device may also operate to regulate the
current passing through the cells in accordance with the
- 21 -
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.
105360~;
tempe~ature to.ma~nta~n.t~e tempe~ature ~ithin.a.desired
range.
Ha~ng thus genexall~ described the invention,
- reference ~ill ~e made.to t~e accompanying dra~ings, in ~hich:
~URE 1 is a sc~emat~c.s~de.sect~onal view of an
electrolytic cell operating to produce a mixture
of h~drogen and oxygen,
F~URE 2 is a side sect~onal vie~ of a multi-plate
~ electrolytic cell;
;~ 10 PI~URE 3 is a side sectional.view o~ a .pressure-
responsive safety device connected in series
' ~ith.an electrolytic cell;
. FIGURE 4 is a side sectional view of an alternative
form of a safety device suitable for use with
an electrolytic hydrogen-oxygen cell;
FIGURE 5 is a schematic view of an arrangement to
produce a hot flame using electrolytically gen- -
li erated gaseous mixtures;
j FIGURE 6 illustrates an arrangement for the magnetic
separation of oxygen from a mixture of oxygen-
hydrogen;
and
FIGURE 7 illustrates a complete oxy-hydrogen gener-
. ating and ~elding apparatus.
Referring to the drawings, Figure 1 shows schemat-
ically a single electrolytic cell 10 operating to produc~ a
mixture o~ hydxogen and oxygen, which mixture is passed
through a flash-back arrestor 11 to a burner 12. The cell
.~
. - 22 -
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10536~)6
10 contai,~s t~o plate electxodes lOa,and_lOb ~m,exsed in an
electrol~te cons~st~n~ o~ a solution o~ KOH ~n ~ater and
connecta~le through texminals 13 and 14 respectively to a
so ~ e o~ a.c. or d,c. electricity. Preferablyt d.c. is used
as the electr~cal impedance ~f t~e cell ~s much lowe~ ~or d.c.
than for a.c. The s-ource o~ electr~city may be a transformer,
typically of 300 A~ps output rating, conne~cted to the cell
through a br~dge recti~ier. The flash-back arrestor 11 is
constituted by a wa'ter bath in which gas liberated in the cell
10 passes through a tube 15 into the water bath 11 and thence
' through a tube 16 to the burner 12. The arrangement is suit-
able for small welding and ~razing work but becomes too bulky
~, ~or very large work. -
Figure 2 illustrates in vertical cross-section an
~ electrolytic cell 20 which requires a much lower current than
,', the cell illustrated in Figure 1 for a given current input.
', The cell 20 comprises what is in effect a series of cells
j constituted by a plurality of plate electrodes immersed in a
i solution ~f KOH-in water. For convenience the electrodes
~', 20 are designated as 20a for the two electrodes at the ends and
20b for the intermediate electrodes. The electrodes 20a are
, j
connected, via conductors 21 to terminals 22 for connection to
an external supply of electricity. The mixture of hydrogen ~'~
and oxygen which is evolved at the electrodes when an electric
current i8 applied, passes through an outlet opening 23 to a
flash-back arrestor and thence to a burner (not shown in Fig-
ure 2). The series of electrodes 20a and 20b are sealingly
~ mounted in a tube 24 of insulating material which is provided
.~
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1053606
with restricted apextures 24a at the top and 24b at the
~ottom, ~et~een each pai~-.o~ electrodes. The apertures 24a
perm~t gas to escape into t~e space 25 a~ove the sur~ace of
the electrolyt~ and the. apertures 24b.permit.the electrolyte
to enter ~reel~ into t~e s~aces ~et~een each pair of elec-
trodes. By v~rtue of t~s arrangement the electrical resis-
tance Between any tw~ adjacentelectrodes is for less than
that between non-ad;acent electrodes so that the arrangement
is ef~ectively one o~ a large number of individual cells con-
nected in series. A very compact arrangement is therefore
obtained but one which permits a relatively high gas produc-
tion rate for a reasona~ly low current input. For example,
a structure like that shown, consisting ofthe equivalent of,
for example, 120 cells can generate gas at a current input
of 15A (at, for example, 240V) equal to that of a single cell
requiring a current input of approximately 1800A. This
means in practice that a relatively portable apparatus can
be produced w-~ich can be connected.directly, ~ithout a trans-
former, to most domestic electrical supplies and which can
maintain a sufficient rate of gas production for most types
of ~elding work.
An advantage which particularly distinguishes the ...
arrangements disclosed from conventional gas welding apparatus
is that the hydrogen.and oxygen are automatically produced in
substantially the correct proportions to give a neutral flame.
No mixing valves are required and even unskilled personnel can
produce satis~actory welds without difficulty. In fact indi-
cations are that many welds canbe produced better than by any
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~053606
other ~eldi.n~ process.
Figure 3 illustrates a pressure responsive safety
device 30 operably connected in series ~electrically) with an
electrol~tic hydrogenJox~gen cell 31 for regulating the
current pass~ng t~ereth~ough in accordance with the gas pres-
sure be~ng generated, ~e de~ice, or cell 30 comprises a
chamber 30' in communicat~on ~it~ a reservoir 32 via a passage
33. Two conical electrodes 34 and 35 are.mounted in spaced
relation ~ithin the chamber and connected in series between a
. 10 d.c~ source Cnot sho~n~ and the electrolytic cell 31. An
electrolytic solution of KOH and water is provided within the
chamber, a portion of.which enters the reservoir 32. When
the cell 31 is operating to produce hydrogen and oxygen the
pressure o~ the gas being produced acts on the surface of the
' electrolyte in the chamber 30' to,displace an amount of the
~1. electrolyte into the reservoir 32 against back pressure exer-
,~` ted by air trapped in the reservoir, the amount o~ electrolyte
displaced depending on the pressure of the gas in the chamber
30'. At the same time the area of contact between the elec-
trodes and the electrolyte in the cell 30 reduces in propor-
tion to the drop in electrolyte level, causing the electrical
~ resistance of the cell 30 to rise and the current passing
,~` therethrough to fall. Should the gas pressure drop the elec-
¦~ trolyte level in the cell 30 will rise and the current passing
into the cell 31 ~ill also rise. Thus the cell 30 operates
~`. to regulate the rate of gas production in accordance with the
~3~ pressure produced and prevents excess gas pressure to build
I up in the cell 31.
`3~ ~" - 25 -
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1053606
Figure 4 ~llustrates an alternat~ve ~or~ o~ safety
devlce wh~ch is: operabl~.to m,aka or ~reak the connection be-
, t~een an electrol~tic h~dxogen~ox~gen cell (not shown inFigure 4) and.an electr~G current source. The device com-
pri,ses a c~lindri,cal,conta~ner 40 in ~luid com~unication with
a li~uid reservo~r 41 v~a ~ passa~eway 42, and a quantity of
mercury C42')-contained ~n the container and reservoir. Two
electrodes 43 and 44 are disposed one above the other in the
container 4G and are normally ~mmersed inthe mercury with a
conductive path thereby ~ormed between them. The container
is connected electrically in series with an electrolytic cell
Cor cells) and in ~aseous communication therewith through a
hose 45. An increase in gas pressure resulting from genera-
tion of gases by the electrolyt~cell(s) causes the mercury
to be displaced towards the reservoir and the mercury level
in the container 40 to fall. ~hen the pressure exceeds a
predetermined level the..mercury level ~alls below that of the
I electrode 43 and electrical connection between thetwo elec-
,` trodes is broken. The electrical connection is again restored .
` 20 when the gas pressure falls. A non-inflammable liquid, such
i as silicone oil or a suitable fluorinated hydrocarbon such as
,~; ` are marketed under the trade mark FREON is provided on top of
~ the mercury to ensure t~at any arc which may be generated be-
'~, tween the electrode 43 and the mercury is totally isolated
~-1 from the gases above the liquids.
j~ Figure 5 shows schematically an arrangement whereby
: an exceedingly hot flame can be produced using the gaseous
', mixture generated electrolytically by the apparatus previously
I ~ - 26 -
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` 1053606
described. In th~s arrange~ent a mixtuxe of hydxogen and
oxygen, ~refera~l~ in sto~chiometrical proportIon~ is passed
via a line 50 between a pa~r o~ tungsten electrodes 51 to pro-
duce molecular dissociat~on of the h~drogen and the oxygen and
a ver~ hot ~lame 52. ~t can be appreciated that whereas in
an atom~c h~drogen ~lame a s~gn~icant temperature rise is
obtained by str~kin~ an arc in the h~drogen, an even greater
temperature rise can be realised by striking the arc bet~een
the oxygen as well since the dissociation energy of molecular
oxygen is of t~e same order of magnitude as that of molecular
hydrogen.
Figure 6 illustrates an arrangement for the magnetic
separation of oxygen from a mixture of oxygen and hydrogen,
whereby the oxygen can be used for flame cutting. The appar-
atus consists of a chamber 60 containing a magnet 61 and
located in a conduit 62. A mixture of hydrogen and oxygen
j is passed through the conduit and around the magnet 61. The
diamagnetic oxygen is diverted by the magnetic field into a
transverse passageway 63 to a central conduit ~not shown)
leading from this passageway and thence to a flame-cutting
~; head. The paramagnetic hydrogen continues along the conduit,
past the magnet and can be allowed to escape or can be col-
lected, as desired. If the magnet is an electromagnet it
can be turned o~f when hydrogen and oxygen is required as a
mixture, and in that case the downstream side of the conduit
62 can be closed off to prevent the loss of gas.
- Figure 7 illustxates a complete oxy-hydrogen gener-
at~ng~welding apparatus comprising a gas generator 70, a
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1053606
current ~egulating cell 71 and a power suppl~ 72. The con-
struct~on o~ t~e.electrodes.73 o~.the ~eneratox 70 and 74 of
the cell 71 are identical-~ith those illustrated in Figs. 2
and 3 respecti.~ely. In tR~s arran~ement.~ however, the gas
generator 70 and cell 71 are co~bined as an integrated unit
and as such has.s-ome ~eatures not found in the arrangements
sho~n in Figs. 2 and 3. In particular the chamber 75 of the
generator 70 and the c~amber 76 of the current regulator cell
71 are separated b~ two partitions 77 and 78 de~ining between
them a passageway communicating between the two chambers.
The respective electrodes o~ the cell 71 and generator 70 are
connected electrically in series with the.power supply.
. Gas produced by electrolysis in the chamber 75 rises
into the space in the. chamber above the electrodes 73, passes
down the passageway between the.partitions 77 and 78, bubbles
through the electrolyte in the chamber 76 and thence.passes
through an outlet opening 79 to a burner 80. An air trap
reservoir 81 is formed integrally with the cell 71 and is in
liquid communication therewith through an opening between the
bottom of the reservoir and the cell. ~hen the pressure of
the gas generated by the generator 70 rises, this pressure
causes the electrolyte in the chamber 76 to be displaced into
the reservo~r.81 resulting in a reduction of the current
being passed to the generator 70 by the mechanism previously
described in relation to Fig. 3 of the drawings. In this way
the cell 71 effectively monitors the gas pressure and regu-
lates the current to maintain an approximately constant pres-
sure. To ensure against the possibility that the pressure
~,
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1053606
s~ould accidentall~ exceed a predetermined maxLmu~.safe Yalue,
a spring~loaded sa~et~ pxessure val~e 82 is.prov~ded at the
top o~ t~e reservoir 81 to release the excess pressure into
the atmosphere.
T~e burnex.80. i~.pr.ov~ded.~th a ~lash-backarrestor
in the ~orm of a porous ceram~c pellet 83 located in the gas
flow path between the handle part 84 o~ the burner and the
burner tip 85. The flash-back arrestor acts by quenching any
flame blowing back into the burner before the flame has a
chance to reach the hose 86 connecting the burner with the
gas generator.
The po~er supply is of the universal type, that is,
it is provided with a transformer 87 connectable to an alter-
nating current electrical supply andFrovided with a number of
electrical outlets for various purposes. One winding of the
transformer-is connected to a bridge rectifier which provides
~ the d.c. current for the gas generator. Another winding is.l used for arc welding or can be used to supply an arc for
atomic oxy-hydrogen welding. It will.be appreciated that
. 20 the trans~rmer is optional and that the generator can be
'~ connected directly to the mains. In fact the bridge recti-fier is not essential either and can be omitted if desired.
~j In the operation of apparatus of the type described
j it is often required to conveniently change between neutral
and oxidising flames, for example when changing from a wel-
ding operation to a cutting operation and the present invention
makes provision for the variation of these functions. ~riefly,
I in accordance with the present invention, apparatus for either
: . 29
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1053606
oxy-h~drogen ~elding or.cuttin~ ~a~ co~prise..a.~irst.electro-
l~tic generator ~or generatin~. hydrogen and oxygen ~y the
electrol~sis o~ ~ater ~n substantiall~ stoic~iometric propor-
ti.ons to produce a neutral.~lame and.a further electrolytic
generator ~rom ~ic~ ~xdrogen and oxy~en are separatel~ deli-
vered, wit~ means ~or adding either t~e hydrogen from this
furt~er cell, or t~e oxygen ~rom the ~urther generator to the
gas mixture obtained from t~e first generator. This arrange-
ment results in.a most ef~icient combination of functions when
a neutral ~lame or other is required. The hydrogen gas pro-
duced by the ~urther generator, when added to the flame mix-
ture, burns ~ith atmospheric oxygen thereby producing a re-
ducing-flame. When an oxidising flame is required, the addi-
tional hydrogen is cut o~ and the oxygen produced by the
further generator is added to the flame mixture. It will be
appreciated that various designs can be employed for either
generator, ~or example, they may be completely independent or
they may share a common electrolyte. The ~urther gas gener-
ator can also, in practice, be made somewhat smaller than
the other generator since it does not ha~e to produce the
bulk of the gas reguired.
It has.been.~ound that welding with hydrogen and ~ -
oxygen in an exact 2 to 1 ratio (as when the gases are pro-
`; duced electrolytically-) results in a particularly clean,
oxide free welded surface and a strong welded joint. For
the same quality welding to be produced by conventional gas
welding technique substantially greater skill is required and,
~i~
~ in the case o~ conventional hydrogen welding, for example,
t~ ~
3 0 -
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1053606
good welded jo~nts are obta~ned only with ~reat difficulty
due to t~e extreme dif~icult~ in obta~ning an~ maintaining a
neutral flame. ~ith the met~od of the present invention
there is no di~iculty in obta~ning a neutral ~lame, and hence
the ease ~ith wh~c~ hi~ quality ~elds can be obtained.
~ inally, it can somet-imes be convenient to store
hydrogen and/or oxygen, generated electrolytically in a
specially designed container, or to slo~ly accumulate these
gases and then, when required, usingff~e accumulated stored
gas for extra heavy work ~or a short time. It is quite haz-
ardous to pressurise a mixture of hydrogen and oxygen under
very high pressures, of course, but it is possible, in accor-
dance with one aspect of the invention, to store a useful
` amount of gas in a relatively small volume at lo~ pressures
'J, and this can be done by using a highly gas absorbent metal
~ in the storage container. The metal palladium, for example,
`~ can absorb up to 900 times its own volume of hydrogen and can
be used with advantage for this application. In fact useful
! amounts of hydrogen, for small scale brazing work can readily
be stored in a small hand held container, containing a gas
~bsorbent rslterIal.
:~j
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