Portable apparatus for welding by means of an oxi-gas flame

Portable apparatus for welding by means of an oxy-gas flame, such as an oxy-acetylene or an oxy-petroleum gas flame or the like, comprises a device for supplying the gaseous fuel in gaseous form under pressure, a combustion oxygen generator and means for pressuring said combustion oxygen generator so as to make the oxygen available at a pressure compatible with the fuel delivery pressure, these means being realized by a connection between the oxygen generator and the fuel supply device.

Welding and cutting are carried out at the present time using a suitable 
torch fed with a mixture of oxygen and an appropriate gaseous fuel, which 
can be acetylene, liquefied petroleum gas or the like. 
The fuel is supplied either from a high pressure cylinder or from a 
suitable generator, which in the case of acetylene is fed with calcium 
carbide and water. The oxygen, which in reality is the indispensable means 
for attaining high temperature, is always supplied from a high pressure 
cylinder. 
A high temperature welding torch always requires oxygen and is never 
self-contained, and in a certain sense forms a non-portable installation 
together with the cylinders or equipment for supplying the fuel and the 
combustion supporting oxygen. 
This greatly limits the application of this type of very high temperature 
welding, of the order of 2000.degree. C., because for obvious reasons the 
known apparatus are very bulky and cannot be made transportable. 
This is due mainly to the need for providing a high pressure oxygen 
cylinder which is of large overall size, and is not always easy to obtain. 
In clarifying the state of the art on which the present invention is based, 
it should be noted that there are methods for producing oxygen on the 
spot, such as hydrolysis of water, but these methods have so far not been 
used in welding, as the oxygen obtained is not of sufficient pressure for 
use for this purpose. This lack of pressure results in an insufficient 
mixing with the gaseous fuel, together with an insufficient gas 
throughput. 
The object of the present invention is to provide an apparatus for welding 
by means of an oxy-gas flame, which is completely self-contained as 
regards its oxygen supply, and which can be fitted into a small sized 
container easily transportable by hand, such as a portable case. This 
object is attained according to the invention by a combination comprising 
an oxygen generator and a small pressurised cylinder of fuel gas; in this 
combination the entire oxygen generator operating under pressure, said 
pressure being obtained directly from the fuel gas cylinder. According to 
a further aspect of the invention, the oxygen generator is of the 
catalytic type. According to a further aspect of the invention, the fuel 
is liquefied petroleum gas, such as butane, propane or the like. 
The apparatus according to the present invention can be constituted in 
practice by an oxygen generator based on the principle of continuously 
producing oxygen from hydrogen peroxide using a suitable catalyst. Said 
oxygen generator is combined with a fuel gas generator consisting simply 
of a small cylinder containing liquid gas (butane, propane of the like). 
Obviously the liquid gas can be replaced by acetylene, methane, petrol or 
the like by suitable changing the fuel gas generator in known manner. 
Various metal-based or ground glass-based substances can be used for 
decomposing the hydrogen peroxide to give pure oxygen. These processes are 
not described as they are known per se. 
Thus whereas the invention preferably comprises a small cylinder with a 
pressure reducer for the fuel gas, it comprises an actual small plant for 
the oxygen, which is very economical and can be divided into the following 
parts: 
1. A vessel for containing the hydrogen peroxide; 
2. A vessel which acts as a reaction chamber for the exothermic 
decomposition of the hydrogen peroxide; 
3. A vessel which acts as a condenser for the water vapour which is 
generated together with the oxygen in the reaction chamber; 
4. One or more vessels in which the oxygen is scrubbed and further cooled 
by bubbling through water. 
A cock and non-return valve together with a filter for the hydrogen 
peroxide are provided to enable the unit to operate both continuously and 
intermittently. 
Further according to the invention, downstream of the pressure reducer 
through which the fuel gas cylinder supplies the torch, there is provided 
a branch connected to the vessel in which the oxygen is developed, so that 
this latter is available at the same pressure as the fuel. 
Obviously as an alternative, the vessel in which the oxygen is developed 
can be pressurised using its own means, for example by means of a pump or 
a cylinder of compressed air of suitable pressure.

FIGS. 1 and 2 show that the apparatus according to the invention is 
contained in a portable metal case composed of a lower base (1) and an 
upper cover (2). 
As can be clearly seen in FIG. 2, these two parts are both in the shape of 
a "U", upright for the base (1) and inverted for the cover (2), their 
vertical arms being orthogonal to each other so that when they are 
assembled together, these parts define a substantially parallelepiped 
closed container. 
The opposing ends of the lower longitudinal edges of the cover (2) are 
provided with articulated hooks (8) for engaging with suitable projections 
branching from the bottom of the base (1). 
As shown in FIG. 1, one of the vertical walls of the base (1) defines a 
convenient instrument panel for monitoring and adjusting the correct 
operation of the apparatus according to the invention. At the top right 
hand corner of this instrument panel there are two through bores through 
which emerge a flexible hose (14) for the combustion supporting gas 
(oxygen) and a flexible hose (15) for a fuel gas, for supplying the torch 
(15). In proximity to this instrument panel, the cover (2) is provided 
with a cooling grid (5) which extends over both its upper wall and one of 
its side walls. This latter side wall of the cover (2) also comprises two 
vertical slots (3) which allow the water level to be determined in the 
pair of vessels (23) and (24) located inside the portable case which 
contains the apparatus. The upper wall of this cover (2) is also provided 
with a handle (4) for transporting the apparatus. 
Again with reference to FIGS. 1 and 2, the upper wall of the cover (2) 
comprises a circular aperture (7) for mounting over the nozzle or neck of 
a vessel (26) which is closed by a suitable cap (6). 
On that side wall of the cover (2) which is opposite the wall comprising 
the two vertical slots (3), there are provided two hooks (9) around which 
the pair of flexible hoses (14) and (15) is wound, and a pair of brackets 
(10) for supporting the torch (16) when not in use. 
On the upper horizontal edge of the inner wall of the instrument panel is 
fitted a cylindrical reaction chamber (27). A suitable quantity of lead 
dust or another equivalent catalyst is placed inside this chamber 27. A 
vessel (26) for containing hydrogen peroxide (H.sub.2 O.sub.2) is disposed 
on the floor of the base (1) in proximity to the instrument panel, on the 
same side as that vertical wall of the cover (2) which carries the hooks 
(9) and brackets (10). 
On the opposite side of the floor of base (1) there is disposed a chamber 
(25) for collecting the reaction products, and which terminates at the 
instrument panel by means of a discharge cap (17) as shown in FIG. 1. As 
shown in FIG. 2, at the rear of this collection chamber (25) there are two 
cooling vessels (23) and (24) connected in series, both of the bubble 
type. Water is present in these latter, and they are provided on their 
upper wall with a suitable cap, (55) and (56) respectively. 
A cylinder of liquid gas (22) of the type normally used for camping and 
which is easily available commercially is disposed on the floor on the 
other side of the base (1). This liquid gas cylinder (22) is fitted with a 
cock or valve (28) at its top. 
The purpose of the vertical slots (3) is now apparent, in that they allow 
the water level in the vessels (23) and (24) to be seen, these being 
advantageously constructed of a transparent synthetic material. 
With reference to FIG. 1, the instrument panel comprises two level 
determination viewing means (21) for the hydrogen peroxide vessel (26) and 
the collection chamber (25) for the reaction products respectively. 
A description is given hereinafter with reference to FIG. 3, of the 
connections between the various vessels disposed on the floor of the base 
1. In this figure, the full line indicates the path or paths followed by 
the fuel gas. 
The double dashed line indicates the path followed by the hydrogen 
peroxide, whereas the single dashed line indicates the path followed by 
the oxygen. 
As previously stated, the gas generator of the apparatus according to the 
invention is constituted essentially of a cylinder (22) of the type 
normally used for camping, and containing a liquefied gas such as butane, 
propane or the like. A conduit (51) branches from the cock (28) of 
cylinder (22) and is connected to a pressure reducer (30), its adjustment 
knob (19) being located on the instrument panel of the apparatus. 
A conduit (53) is connected from the pressure reducer (30) to a pressure 
gauge (20) which is also located on the instrument panel. A cock 66 is 
connected into the conduit (53), and its operating lever 12 is located on 
the instrument panel. 
Immediately downstream of this cock (66), a conduit (52) branches from the 
conduit (53) and is connected to the top of the hydrogen peroxide vessel 
(26). A gas flow regulator (29), of which the knob (18) is located on the 
instrument panel as shown in FIG. 1, is connected into the conduit (53) 
downstream of the connection between this latter and the conduit (52). The 
flexible gas hose (15), the initial part of which comprises a suitable 
non-return valve (54), is connected to that portion of the conduit (53) 
between the gas regulator (29) and pressure gauge (20). A conduit (50) 
branches from the base of the hydrogen peroxide vessel (26), and is 
connected to a cock (67), its control lever (11) being located on the 
instrument panel. 
Although not shown, the initial part of the conduit (50) located in the 
vessel (26) is provided with a suitable filter. 
A conduit (49) is connected between the cock (67) and one end of the 
reaction chamber (27). A sized orifice (31) is fitted into the conduit 
(49) for the purpose of making the feed of hydrogen peroxide to the 
tubular reaction chamber (27) uniform. 
As stated, the tubular reaction chamber (27) is filled with a suitable 
catalyst, which in this specific case is granulated lead. 
A conduit (48) runs from the other end of the tubular reaction chamber (27) 
to the top of the collection chamber (25) for the reaction products. This 
latter comprises a discharge cap (17) located on the instrument panel. A 
conduit (47) runs from the top of the collection chamber (25) for the 
reaction products to the bottom of the cooling vessel (23). A conduit (46) 
runs from the top of this latter to the bottom of the cooling vessel (24). 
Although not shown, that end of the conduit (47) disposed inside the 
cooling vessel (24) is provided with a suitable perforated cap, the 
purpose of which is to prevent the formation of large bubbles during 
bubbling of the oxygen, which would make the flame from the torch (16) 
either trembling or intermittent. 
A conduit (45) runs from the top of the cooling vessel (24) to the upper 
end of a vapour condensation column (13) disposed on the side of the 
instrument panel is shown in FIG. 1. 
As shown in FIGS. 1 and 3, the lower end of said vapour condensation column 
(13) is provided with a suitable emptying cap (32). The flexible hose (14) 
for feeding oxygen to the torch (16) is connected to the other end of the 
column (13). 
The operation of the apparatus according to the invention is as follows. 
The water level in the cooling vessels (23) and (24) is easily seen through 
the vertical slots (3) in the apparatus cover (2). 
In addition, the viewing means (21) enable the level of the hydrogen 
peroxide in the vessel (26) and of the water in the collection chamber 
(25) for the reaction products to be determined. 
The hydrogen peroxide level in the vessel (26) can be easily topped up 
through the nozzle closed by the cap (6). The water in the chamber (25) is 
discharged through the cap (17), and the vapour condensation column (13) 
is emptied by removing the cap (32). 
The cooling vessels (23) and (24) are filled through the nozzles closed by 
the caps (55) and (56) after lifting the cover (2) off the base (1). 
When the torch (16) is not in use, it is fitted on to the brackets (10), 
the flexible hoses (14) and (15) being wound over the hooks (9) on the 
cover (2). 
When the apparatus according to the invention is to be used, the cocks (67) 
and (66) are firstly opened by the control levers (11) and (12), and the 
pressure reducer (30) and gas regulator cock (29) are then adjusted. This 
latter operation is necessary in order to suitably adapt the flame of the 
torch (16) to the type of work which the torch (16) is required to do. 
With this arrangement, the gas generator of the apparatus, in the form of 
the liquid gas cylinder (22), is able to pressurise the oxygen generator. 
This is because the pressurised fuel gas is passed through the cock (28), 
the conduit (51), the pressure reducer (30), the cock (66) and the conduit 
(52) into the space above the level of the hydrogen peroxide in the vessel 
(26). 
In this manner, the hydrogen peroxide is obliged to pass through the 
conduit (50) and through the cock (67) and conduit (49) into the tubular 
reaction chamber (27). The feed of this hydrogen peroxide into the tubular 
reaction chamber (27) is made uniform by the orifice (31). 
Because of the lead catalyst, an exothermic decomposition reaction takes 
place inside the reaction chamber (27), by which the entering hydrogen 
peroxide is decomposed into two products, namely a liquid product (water) 
and a gaseous product (oxygen). 
These two products are fed through the conduit (48) into the collection 
chamber (25) for the reaction products, from which the oxygen passes 
through the conduit (47) into the cooling vessel (23). 
In this vessel, the oxygen undergoes a first cooling with simultaneous 
scrubbing, and then passes through the conduit (46) into the second 
cooling vessel (24) where it undergoes further cooling and further 
scrubbing. 
The oxygen then passes through the conduit (45) and through the vapour 
condensation column (13) where any moisture still in suspension in the 
oxygen is retained. 
From the outlet of the column (13), the oxygen is fed into the flexible 
hose (14) to supply the torch (16), which also receives the fuel gas fed 
through the flexible hose (15). 
The invention is not limited to the single embodiment heretofore described, 
and modifications and improvements can be made thereto without leaving the 
scope of the inventive idea. 
Thus, even though the fuel gas generator referred to is of the type 
indicated by (22), containing butane, propane or similar liquefied gases, 
it is apparent that this liquid gas can be replaced by acetylene, methane, 
petrol or similar fuels by modifying the fuel gas generator in a suitable 
manner using known means. 
Moreover, although in this specific example, the hydrogen peroxide is 
decomposed in the tubular reaction chamber (27) using granulated lead, it 
is apparent that the pure oxygen can be produced using normally metal 
based substances other than the said lead. 
Finally, although the pressure for the oxygen generator is preferably 
derived directly from the gas generator (22), said pressure can be 
obtained or derived from a system different from the gas generator, such 
as a pump or a pressure cylinder.