CA1065242A - Gas welding torch - Google Patents
Gas welding torchInfo
- Publication number
- CA1065242A CA1065242A CA292,541A CA292541A CA1065242A CA 1065242 A CA1065242 A CA 1065242A CA 292541 A CA292541 A CA 292541A CA 1065242 A CA1065242 A CA 1065242A
- Authority
- CA
- Canada
- Prior art keywords
- gas
- oxygen
- mixing chamber
- director
- aperture
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23D—BURNERS
- F23D14/00—Burners for combustion of a gas, e.g. of a gas stored under pressure as a liquid
- F23D14/38—Torches, e.g. for brazing or heating
- F23D14/40—Torches, e.g. for brazing or heating for welding
Abstract
ABSTRACT OF THE DISCLOSURE
A welding torch. The torch has a hand piece. An oxygen conduit in the hand piece has a connection at its upstream end for connecting to an oxygen supply hose. There is a tubular oxygen director at its downstream end. The tubular oxygen director is in gas flow communication with the conduit. A gas mixing structure comprises at least one mixing member which defines, with the oxygen director, a primary mixing chamber. A combustible gas conduit in the hand piece has a connection at its upstream end for connec-ting to a combustible gas supply hose. Walls in the hand piece place the downstream end of the gas conduit into gas flow communication with the primary mixing chamber. The gas mixing structure comprises a gas mixture directing aperture having a length exceeding its diameter and walls that define a secondary mixing chamber of greater volume than the primary mixing chamber, a length which exceeds its diameter, and a diameter which exceeds that of the gas mixture directing apertures. A discharge nozzle is at the downstream end of the secondary mixing chamber. The oxygen director, primary mixing chamber, gas mixture directing aperture, secondary mixing chamber and nozzle all have a common polar axis. The torch is easy to use and has reduced prospects of blow-back.
A welding torch. The torch has a hand piece. An oxygen conduit in the hand piece has a connection at its upstream end for connecting to an oxygen supply hose. There is a tubular oxygen director at its downstream end. The tubular oxygen director is in gas flow communication with the conduit. A gas mixing structure comprises at least one mixing member which defines, with the oxygen director, a primary mixing chamber. A combustible gas conduit in the hand piece has a connection at its upstream end for connec-ting to a combustible gas supply hose. Walls in the hand piece place the downstream end of the gas conduit into gas flow communication with the primary mixing chamber. The gas mixing structure comprises a gas mixture directing aperture having a length exceeding its diameter and walls that define a secondary mixing chamber of greater volume than the primary mixing chamber, a length which exceeds its diameter, and a diameter which exceeds that of the gas mixture directing apertures. A discharge nozzle is at the downstream end of the secondary mixing chamber. The oxygen director, primary mixing chamber, gas mixture directing aperture, secondary mixing chamber and nozzle all have a common polar axis. The torch is easy to use and has reduced prospects of blow-back.
Description
-` 1065Z4Z
This invention relates to a welding torch which is useful for the heating or welding of metals.
In my Australian Patent 460,066 I described and claimed 5. a torch attachment for the attachment to a hand piece bend of a torch, the attachment containing a mixing chamber extending in a downstream direction from the adaptor and terminating in a nozzle, the mixing chamber being at least eight times its diameter and the chamber and 10. nozzle walls being free of abrupt steps so that gas passing therethrough was in a substantially non-turbulent streamline.
The torch attachment disclosed in that specification had a characteristic of providing a concentrated higher temperature heat pattern than previously proposed torches, and because of 15. this characteristic has proved to be economical in gas usage.
Independent tests undertaken by the University of Adelaide, showed gas savings totalling about 8u~. However, there are certain difficulties which are encountered, prohably the most serious of which is that the handpiece becomes cumbersome 20. and awkward to use due to a relatively long mixing chamber attached to an existing torch, and one ob~ect of this ;nvention is to provide improvements wherein a higher temperature and more concentrated heat pattern can b~ achieved than with the usual existing torches, but with a much neater and more convenient 25. hand piece.
The closest prior art known to t~ Applicant is the U.S.
Patent No. 1,418,245 issued to FOUCHE wherein oxygen and acet-ylene are mixed in forwardly moving annuli, but the mixed gases pass straight into a single mixing chamber before issuing from a nozzle.
.
:.
~ ~ .
1~16529~Z
Safety demands have a great influcnce on welding torch configuration. "Blow-back" is a phcnomenon caused by a flame front travelling back through the nozzle aperture and into the mixing chamber of the torch. In torches as presently used, 5. more oxygen is re~uired than acetylene (to satisfy the com-bustijn equation 502+2C2H2^-~CO2+2~l2O), and it is customary for a higher pressllre of oxygen to be used than acetylene. It becomes possible for oxygen to enter the a~e~ylene hose, and in order to reduce blow back danger, acetylene is introduced 10. into the mixing chamber of prior art torches through a plurality of small apertures. However "blow-back" can result in a small explosion within the mixing chamber, and instances still occur of explosion damaging the acetylene gauges, due to combustion within the acetylene hose itself, 15. notwithstanding the existence of the small apertures. It is another object of the invention to improve the safety of a torch, such that there ;s less likelihood of "blow-back" extend-ing into the hose which conveys the combustible gas (the acetylene hose).
20.
Briefly in this invention a torch is provided with ` components which define a primary mixing chamber of relatively small volume, a secondary mixing chamber of relatively large volume, a gas mixture directing aperture the length of which is 25. much greater than its diameter, the directing aperture directing gas after being mixed in the primary mixing chamber into the secondary mixing chamber, and a discharge nozzle at the downstream end of the secondary mixing chamber.
~06524Z
If the chambers, the directing aperture and the nozzle are co-axial, and if they are correctly dimensioned, it becomes possible to use equal pressures for oxygen and acety-lene, and thereby reduce danger of oxygen entering the acety-5. lene hose. It has also been found possible to achieve higher temperatures and more concentrated heat than was achieved with the torch described in said patent 460,066.
If the torch is arranged to have a central stream of oxygen directed into the primary mixing chamber, and this entrains an 10. annulus of acetylene, then the further oxygen required and supplied from atmosphere is entrained by the smooth-flowing non-turbulent gases issuing from the nozzle, into the acetylene-rich annulus. Furthermore, the gas surrounding the welding zone comprises steam, nitrogen and carbon dioxide, -~ 15. so that corrosion near the weld zone is largly inhibited.
Still further, a phenomenon is observed, that a higher temperature exists at the centre of the flame than in prior - art torches, and this is thought to be due to non-uniform combustion over the cross-section of the flame.
; 20. More specifically, this invention consists of a welding torch comprising a hand piece, an oxygen conduit in the hand ; piece having connection means at its upstream end for connecting to an oxygen supply hose, and a tubular oxygen director at its downstream end, said tubular oxygen director being in 25. gas flow communication with the conduit, a gas mixing structure comprising at least one mixing member which defines with the oxygen director, a primary mixing chamber, a combustible gas conduit in the hand piece having connection means at its :;
~ - 4 -- . : , 1~6~Z42 ;:
upstream end for connecting to a combustible gas supply hose, and walls in the hand piece placing the downstream end of the gas conduit into gas flow communication with the primary mixing chamber, the gas mixing structure comprising 5. a gas mixture directing aperture having a length exceedin-~ its ` diameter, and walls defining a secondary mixing chamber ofgreater volume than the primary mixing chamber, a length which exceeds its diameter, and a diameter which exceeds that of said ~^ gas mixture directing aperture, and a discharge nozzle 10. at the downstream end of said secondary mixing chamber, said oxygen director, primary mixing chamber, gas mixture directing aperture, secondary mixing chamber and nozzle all having a common polar axis.
With this arrangement a stream of oxygen and acetylene 15. (for example) which issues from the nozzle provides a very smooth flame having a very concentrated high temperature central portion even though the amount of oxygen used is less than with a conventional torch. The torch is capable of even higher speed welding (for the same gas consumption) than the 20. combined torch and attachment described in the specification of said Australian Patent 460,066. Instead of the ratio being 5 parts by weight (2 by volume) of oxygen to 2 parts by weight (1 by volume) of acetylene approximately for perfect combustion, the ratio can be reduced to approximately 25. 1:1 parts by weight (the other oxygen coming from the surrounding atmosphere), and furthermore the gas usage can be still further reduced.
.
106529~Z
Some operators use wcldil-g torches wit~ ~heir right hand and others with their le~t hand, and in another aspect of this invelltion the torch hand piece is provided with swivel nuts at the upstream ends of tl-e oxygen and gas conduits 5. respectively, valves coupled to the swivel nuts, and hose unions on the inlet ends of the respective valves. By relaxing the swivel nuts, the valves can then be rotated and re-positioned to suit the user.
In another aspect of the invention, the hand piece is 10. provided with a handle through which the oxygen and gas -conduits pass.
In another aspect of the invention, the hand piece is provided with a connector block secured to it and having the gas flow conduits extending through the connector block, 15. the connector block being of relatively small cimension so that the hand piece may be used as a "pencil torch".
~wo embodiments of the invention are described hereunder -in some detail with reference to and are illustrated in the ;; accompanying drawings, in which Fig. 1 is a partly sectional elevation of a welding torch according to a first embodiment, Fig. 2 is an "exploded" elevation of the oxygen director, the gas mixing structure and the nozzle, 25. Fig. 3 is a sectional elevation showing said elements assembled, and being drawn to an enlarged scale, - Fig. 4 is a fragmentary sectional elevation showing twomixing members of the gas mixing structure separated to a~low entrainment of air into the secon(lary mixing chamber, and Fig. 5 is an elevation of a "pencil torch", which is the second emboclimcnt of the invention.
. In the first embodiment of Figs. l, 2, 3 and 4 a w~l~]ing torch 10 is provided with a hand piece 11, and at the "heel"
of the hand piece there are provided two unions each designated 12, each with a swivel nut to which is connected a respective valve, one desigated 13 for oxygen and the other designated 10. 14 for combustible gas (herein simply termed "gas", and usually intended to mean acetylene although butane and other gases can also be used Wl th this invention). The swivel nut arrangement enables each valve to be rotated to occupy a position most convenient for the user, this being a very 15. desirable feature for arranging the hand torch to be used by right or left hand operators.
. . ~
In this embodiment, the hand piece 11 is provided with a formation such as to make it convenient to be grasped by an operator's hand, and terminates at the end away 20. from the nut unions in a boss 17. The boss contains a threaded aperture 18 extending through at an angle with respect to the longitudinal axis of the han(,~e portion of the hand piece, and the hand piece contains two conduits, one being an oxygen conduit 19 at the rear end and the other beinc~ a gas 25. conduit 20 at the front end, the conduits being parallel or nearly parallel and texminating in the threaded aperture 18 with the oxygen conduit 19 being behind the gas conduit 20.
The conduits may be formed by drilled holes in an otherwise 1~65Z4~2 solid handle, but a "light weight" handle as illustrated is usually preferred by operators.
The threaded aperture is threadably engaged by, firstly, an oxygen director 24, the oxygen director being a threaded member having a thread 25 extending for portion of its length, the thread 25 itself being interrupted by walls which form an annular recess 26. The front or downstream end of the oxygen director has a stem 27 which is tapered around its outer periphery, and the stem surrounds a central 10. axially extending oxygen directing aperture 28 which is of diamter approximately equal to the maximum diameter nozzle tip which will be used, in this embodiment the diameter being
This invention relates to a welding torch which is useful for the heating or welding of metals.
In my Australian Patent 460,066 I described and claimed 5. a torch attachment for the attachment to a hand piece bend of a torch, the attachment containing a mixing chamber extending in a downstream direction from the adaptor and terminating in a nozzle, the mixing chamber being at least eight times its diameter and the chamber and 10. nozzle walls being free of abrupt steps so that gas passing therethrough was in a substantially non-turbulent streamline.
The torch attachment disclosed in that specification had a characteristic of providing a concentrated higher temperature heat pattern than previously proposed torches, and because of 15. this characteristic has proved to be economical in gas usage.
Independent tests undertaken by the University of Adelaide, showed gas savings totalling about 8u~. However, there are certain difficulties which are encountered, prohably the most serious of which is that the handpiece becomes cumbersome 20. and awkward to use due to a relatively long mixing chamber attached to an existing torch, and one ob~ect of this ;nvention is to provide improvements wherein a higher temperature and more concentrated heat pattern can b~ achieved than with the usual existing torches, but with a much neater and more convenient 25. hand piece.
The closest prior art known to t~ Applicant is the U.S.
Patent No. 1,418,245 issued to FOUCHE wherein oxygen and acet-ylene are mixed in forwardly moving annuli, but the mixed gases pass straight into a single mixing chamber before issuing from a nozzle.
.
:.
~ ~ .
1~16529~Z
Safety demands have a great influcnce on welding torch configuration. "Blow-back" is a phcnomenon caused by a flame front travelling back through the nozzle aperture and into the mixing chamber of the torch. In torches as presently used, 5. more oxygen is re~uired than acetylene (to satisfy the com-bustijn equation 502+2C2H2^-~CO2+2~l2O), and it is customary for a higher pressllre of oxygen to be used than acetylene. It becomes possible for oxygen to enter the a~e~ylene hose, and in order to reduce blow back danger, acetylene is introduced 10. into the mixing chamber of prior art torches through a plurality of small apertures. However "blow-back" can result in a small explosion within the mixing chamber, and instances still occur of explosion damaging the acetylene gauges, due to combustion within the acetylene hose itself, 15. notwithstanding the existence of the small apertures. It is another object of the invention to improve the safety of a torch, such that there ;s less likelihood of "blow-back" extend-ing into the hose which conveys the combustible gas (the acetylene hose).
20.
Briefly in this invention a torch is provided with ` components which define a primary mixing chamber of relatively small volume, a secondary mixing chamber of relatively large volume, a gas mixture directing aperture the length of which is 25. much greater than its diameter, the directing aperture directing gas after being mixed in the primary mixing chamber into the secondary mixing chamber, and a discharge nozzle at the downstream end of the secondary mixing chamber.
~06524Z
If the chambers, the directing aperture and the nozzle are co-axial, and if they are correctly dimensioned, it becomes possible to use equal pressures for oxygen and acety-lene, and thereby reduce danger of oxygen entering the acety-5. lene hose. It has also been found possible to achieve higher temperatures and more concentrated heat than was achieved with the torch described in said patent 460,066.
If the torch is arranged to have a central stream of oxygen directed into the primary mixing chamber, and this entrains an 10. annulus of acetylene, then the further oxygen required and supplied from atmosphere is entrained by the smooth-flowing non-turbulent gases issuing from the nozzle, into the acetylene-rich annulus. Furthermore, the gas surrounding the welding zone comprises steam, nitrogen and carbon dioxide, -~ 15. so that corrosion near the weld zone is largly inhibited.
Still further, a phenomenon is observed, that a higher temperature exists at the centre of the flame than in prior - art torches, and this is thought to be due to non-uniform combustion over the cross-section of the flame.
; 20. More specifically, this invention consists of a welding torch comprising a hand piece, an oxygen conduit in the hand ; piece having connection means at its upstream end for connecting to an oxygen supply hose, and a tubular oxygen director at its downstream end, said tubular oxygen director being in 25. gas flow communication with the conduit, a gas mixing structure comprising at least one mixing member which defines with the oxygen director, a primary mixing chamber, a combustible gas conduit in the hand piece having connection means at its :;
~ - 4 -- . : , 1~6~Z42 ;:
upstream end for connecting to a combustible gas supply hose, and walls in the hand piece placing the downstream end of the gas conduit into gas flow communication with the primary mixing chamber, the gas mixing structure comprising 5. a gas mixture directing aperture having a length exceedin-~ its ` diameter, and walls defining a secondary mixing chamber ofgreater volume than the primary mixing chamber, a length which exceeds its diameter, and a diameter which exceeds that of said ~^ gas mixture directing aperture, and a discharge nozzle 10. at the downstream end of said secondary mixing chamber, said oxygen director, primary mixing chamber, gas mixture directing aperture, secondary mixing chamber and nozzle all having a common polar axis.
With this arrangement a stream of oxygen and acetylene 15. (for example) which issues from the nozzle provides a very smooth flame having a very concentrated high temperature central portion even though the amount of oxygen used is less than with a conventional torch. The torch is capable of even higher speed welding (for the same gas consumption) than the 20. combined torch and attachment described in the specification of said Australian Patent 460,066. Instead of the ratio being 5 parts by weight (2 by volume) of oxygen to 2 parts by weight (1 by volume) of acetylene approximately for perfect combustion, the ratio can be reduced to approximately 25. 1:1 parts by weight (the other oxygen coming from the surrounding atmosphere), and furthermore the gas usage can be still further reduced.
.
106529~Z
Some operators use wcldil-g torches wit~ ~heir right hand and others with their le~t hand, and in another aspect of this invelltion the torch hand piece is provided with swivel nuts at the upstream ends of tl-e oxygen and gas conduits 5. respectively, valves coupled to the swivel nuts, and hose unions on the inlet ends of the respective valves. By relaxing the swivel nuts, the valves can then be rotated and re-positioned to suit the user.
In another aspect of the invention, the hand piece is 10. provided with a handle through which the oxygen and gas -conduits pass.
In another aspect of the invention, the hand piece is provided with a connector block secured to it and having the gas flow conduits extending through the connector block, 15. the connector block being of relatively small cimension so that the hand piece may be used as a "pencil torch".
~wo embodiments of the invention are described hereunder -in some detail with reference to and are illustrated in the ;; accompanying drawings, in which Fig. 1 is a partly sectional elevation of a welding torch according to a first embodiment, Fig. 2 is an "exploded" elevation of the oxygen director, the gas mixing structure and the nozzle, 25. Fig. 3 is a sectional elevation showing said elements assembled, and being drawn to an enlarged scale, - Fig. 4 is a fragmentary sectional elevation showing twomixing members of the gas mixing structure separated to a~low entrainment of air into the secon(lary mixing chamber, and Fig. 5 is an elevation of a "pencil torch", which is the second emboclimcnt of the invention.
. In the first embodiment of Figs. l, 2, 3 and 4 a w~l~]ing torch 10 is provided with a hand piece 11, and at the "heel"
of the hand piece there are provided two unions each designated 12, each with a swivel nut to which is connected a respective valve, one desigated 13 for oxygen and the other designated 10. 14 for combustible gas (herein simply termed "gas", and usually intended to mean acetylene although butane and other gases can also be used Wl th this invention). The swivel nut arrangement enables each valve to be rotated to occupy a position most convenient for the user, this being a very 15. desirable feature for arranging the hand torch to be used by right or left hand operators.
. . ~
In this embodiment, the hand piece 11 is provided with a formation such as to make it convenient to be grasped by an operator's hand, and terminates at the end away 20. from the nut unions in a boss 17. The boss contains a threaded aperture 18 extending through at an angle with respect to the longitudinal axis of the han(,~e portion of the hand piece, and the hand piece contains two conduits, one being an oxygen conduit 19 at the rear end and the other beinc~ a gas 25. conduit 20 at the front end, the conduits being parallel or nearly parallel and texminating in the threaded aperture 18 with the oxygen conduit 19 being behind the gas conduit 20.
The conduits may be formed by drilled holes in an otherwise 1~65Z4~2 solid handle, but a "light weight" handle as illustrated is usually preferred by operators.
The threaded aperture is threadably engaged by, firstly, an oxygen director 24, the oxygen director being a threaded member having a thread 25 extending for portion of its length, the thread 25 itself being interrupted by walls which form an annular recess 26. The front or downstream end of the oxygen director has a stem 27 which is tapered around its outer periphery, and the stem surrounds a central 10. axially extending oxygen directing aperture 28 which is of diamter approximately equal to the maximum diameter nozzle tip which will be used, in this embodiment the diameter being
2.40 millimetres. A plurality of radially extending apertures 29 intersect the rear end of the oxygen directing aperture 28, 15. and open into the annular recess 26, and the arrangement is such that when the oxygen director is screwed "home", that is to the base of the threaded aperture 18 in the hand piece boss 17, the annular recess aligns with the oxygen conduit and ; oxygen will then pass through the oxygen conduit, the annular 20. recess, the radial apertures and into the oxygen directing aperture to issue therefrom as a high speed stream of relatively small diameter.
Closer to the mouth or downstream end of the threaded aperture 18 in the hand piece boss 17 there is a gas mixing 25. structure generally designated 31 and comprising a primary mixing member 32, the primary mixing member 32 having at its upstream end a gas diffusing skirt 33 which surrounds the ~ tapered stem 27 and bears at its upstream end against a ::
~ - ~3 -`` lO~S;~
shoulder 34 at the upstream end of the tapered stem 27, but the gas diffusing skirt has a relatively large diameter central chamber at its upstream end which constitutes a primary mixing chamber 35, and into which the small diameter stream of oxygen passes. A plurality of small diameter radially extending apertures 37 pass through the gas diffusing skirt, and the arrangement is such that the space surrounding the gas diffusing skirt (the outer diameter of which is less than the thread diameter of the threaded aperture) is in communication with the downstream end of the gas conduit 20, whereby the pressure of gas in the gas conduit and the flow of oxygen combine to entrain gas into the oxygen stream, but near its outer periphery. Thus, there is some mixing of the gas and oxygen in the primary mixing chamber, even through the flow there through is relatively non-turbulent but it is believed that at this stage at least, the core is oxygen-rich. It may be noted that this is in direct contrast with prior art torches many of which have employed complicated arrangements to ensure thorough turbulence of the gases.
As seen best in Fig. 3, radially extending apertures 37 open into a diverging annular space. In the case of blow-back, even if oxygen has entered the acetylene hose, danger of combustion within the hose is reduced by this configuration.
The primary mixing member 32 has a relatively large diameter primary mixing chamber 35 only at its upstream end, and this merges into a relatively small diameter parallel walled aperture which can be regarded as a gas mixture directing aperture 39 at the downstream end, the gas mixture -:' _g_ - ` :
~: lO~S'~4Z
directing aperture in this embodiment being of the same diameter as the oxygen directing aperture (2.40 millimeters) so that the gas mixture which issues therefrom issues as a relatively small diameter relatively non-turbulent stream. Its length however is at least five times greater than its diameter, in this embodiment about 22 millimeters.
This dimension is important and must be adjusted for a torch of any given dimensions by empirical means to achieve optimum results. The threaded outer portion of the primary mixing member 32 projects outwardly from the mouth of the handle, and this is threadably engaged by a small sleeve 41 which constitutes an air entrainment sleeve, the air entrainment sleeve being threaded throughout its length but having a plurality of radially extending apertures extending there-through from a shallow groove 42 in its outer surface. The apertures include three relatively large apertures 43 and three relatively small apertures 44, this arrangement being more suitable for limiting incidence of "blow-back" than if all apertures are of the same size, since it results in uneven gas mixtures within the torch.
The radially extending apertures 43 and 44 are positioned slightly downstream of the downstream end of the primary mixing member 32, but the downstream end of the primary mixing member 32 is provided with a small projecting boss 46 which tapers towards the issue end when the apertures are opened with respect to the gas stream issuing from the primary mixing member, air is entrained with the gas stream as shown in Fig. 4.
: ' ':`
The other or downstream end of the air entrainment sleeve is threadably engaged by a secondary mixing member 48 of the gas mixing structure 31, the secondary mixing member 48 having a . . .
thread extending for most but not all of its length, and 5. the thread is interrupted intermediate its ends by a recess 49 so that an operator can quickly identify when the secondary mixing member has been unsc~ewed sufficiently for the air entrainment aperture 43 and 44 to be exposed. The air entrainment apertures are exposed on]y occasionally, that is lO. when the torch is required for heating of metal as distinct from welding of metal, and large areas of relatively low temperature gas are required to issue from the jet. NOrmally, however, the secondary mixing member is screwed hard against a tapered surface 50 which surrounds the boss 46 of the down-15. stream end of the primary mixing member, and a relatively large diameter central aperture within the member 48 pro~7ides a secondary mixing chamber designated 52.
Screwed on to the downstream end of the secondary mixing member 48 is a nozzle 53, the nozzle 53 having a bore 54 of 20. identica1 diameter to the diameter of the secondary mixing chamber 52, and the bore terminating in tapered walls 55 which terminate in an outlet jet aperture 56. The bore 55 of the nozzle 53, the inner walls of the jet aperture 56 and the bore of the secondary mixing chamber 52 are made as smooth 25. as possible, the smoother the better. In this embodiment the walls of the bore of the secondary mixing chamber 52 are burnished to achieve a high degree of smoothness. It has been found also that the length of the bore which is common to the .
::
', . - .- . .: , :
~065Z4Z
secondary mixing chamber and the upstre~m end of the nozzle should be related to its diameter, unless th~ bore is very long. However, for practical purposes it is desirable tha-t the bore be as short as possible, and should exceed eight times 5- the bore diameter. In this embodiment the bore length is 11.25 x the bore diameter, tha~ is, for a bore diameter of - 6.4 mm the bore length needs to be approximately 72 mm.
It has been found by experimentation that the bore length should be an odd mul~iple of 1.25 x the diameter and at 10. least 8.75 x the diameter to achieve the desired mixing condit-ions. If the bore is increased beyond the 11.25 x diameter of this embodiment, the criticality of its length progessively reduces, and results progressively improve, although the improve-ment is~ 80 slight that in most instances extended lengths are 15. not required. It is also found desirable to control the angle of convergence of the tapered walls 55 which define the end of the secondary mixing chamber bore, and in this embodiment the included cone angle is approximately 54 degress. It should range between 45 and 65 degrees, but the closer it is 20. taken to 54 degrees, the better the results are likely to be. This is believed to be related to the deflection of particles or molecules oE gas Erom the walls of the boreO
Again it has been found for reasons which are not under-stbod, that the jet diameter of the issuing aperture of the 25. nozzle is critical, and ~or any given torch, a series of experiments are required to ascertain which diameters are suitable. In the example of this embodiment, there have been three satisfactory diameters discovered, one being 0.90 millimeters, the second being 1.30 millimeters and the largest ~L0~5'~Z :~
being 2.40 millimeters, that is the same diameter as the diameter of the aperture through the oxygen director and the first mixing member. Diameters between these diameters -~
have been found to give results which are inferior.
In use, gas at low pressure (about 4 p.s.i. or 28 k.p.a.) is delivered at equal volumes to the torch, and not in the theoretically correct 80:32 ratio of oxygen to acetylene, but the flame temperature is extremely high for a very small diameter. A blue smooth cone extends for about nineteen mm.
in the case of the smallest tip, twenty nine mm. for the intermediate tip, and sixteen mm. for the large tip. If butane and oxygen are used then a 1-1 ratio by volume is found to work satisfactorily, but the temperature is much lower than with acetylene.
The primary combustion of the blue cone is known to yield carbon monoxide and hydrogen, and the secondary combustion of the surrounding flame to yield carbon dioxide and steam.
However, the surrounding flame is not oxygen-rich, and oxygen is entrained from the atmosphere by the smooth flowing gases to form the envelope flame. The quantity of entrained oxygen is very much greater than the prior art torches, and the welding takes place under such advantageous conditions that negligible metal oxidation occurs. This in turn simplifies welding of difficult metals such as aluminium and magnesium alloys.
The invention results in such improvements that micro-welding becomes possible, and in a second embodiment ; 1065Z4Z
(illustrated in Fig. 5) the construction is substantially similar to the first and similar numbers designate similar elements, excepting that instead of using a handle as in the first, the hand piece 11 comprises a gas directing block 5. 60 secured to one side, and near one end, of a mounting cylinder 61 which takes the place of the boss of the handle and which is threadably engaged by the oxygen director and by the primary mixing member. The block 60 is provided with two small flexihle tubes 62 to hose valves (not shown) 10. and the device can then be held between the fingers in the manner of a pencil. However, a simple tubular handle 63 is also provided which slips over the device and locks on to the cylindrical member 6 to provide a handle for hand welding if this is required.
;' , ':
:
Closer to the mouth or downstream end of the threaded aperture 18 in the hand piece boss 17 there is a gas mixing 25. structure generally designated 31 and comprising a primary mixing member 32, the primary mixing member 32 having at its upstream end a gas diffusing skirt 33 which surrounds the ~ tapered stem 27 and bears at its upstream end against a ::
~ - ~3 -`` lO~S;~
shoulder 34 at the upstream end of the tapered stem 27, but the gas diffusing skirt has a relatively large diameter central chamber at its upstream end which constitutes a primary mixing chamber 35, and into which the small diameter stream of oxygen passes. A plurality of small diameter radially extending apertures 37 pass through the gas diffusing skirt, and the arrangement is such that the space surrounding the gas diffusing skirt (the outer diameter of which is less than the thread diameter of the threaded aperture) is in communication with the downstream end of the gas conduit 20, whereby the pressure of gas in the gas conduit and the flow of oxygen combine to entrain gas into the oxygen stream, but near its outer periphery. Thus, there is some mixing of the gas and oxygen in the primary mixing chamber, even through the flow there through is relatively non-turbulent but it is believed that at this stage at least, the core is oxygen-rich. It may be noted that this is in direct contrast with prior art torches many of which have employed complicated arrangements to ensure thorough turbulence of the gases.
As seen best in Fig. 3, radially extending apertures 37 open into a diverging annular space. In the case of blow-back, even if oxygen has entered the acetylene hose, danger of combustion within the hose is reduced by this configuration.
The primary mixing member 32 has a relatively large diameter primary mixing chamber 35 only at its upstream end, and this merges into a relatively small diameter parallel walled aperture which can be regarded as a gas mixture directing aperture 39 at the downstream end, the gas mixture -:' _g_ - ` :
~: lO~S'~4Z
directing aperture in this embodiment being of the same diameter as the oxygen directing aperture (2.40 millimeters) so that the gas mixture which issues therefrom issues as a relatively small diameter relatively non-turbulent stream. Its length however is at least five times greater than its diameter, in this embodiment about 22 millimeters.
This dimension is important and must be adjusted for a torch of any given dimensions by empirical means to achieve optimum results. The threaded outer portion of the primary mixing member 32 projects outwardly from the mouth of the handle, and this is threadably engaged by a small sleeve 41 which constitutes an air entrainment sleeve, the air entrainment sleeve being threaded throughout its length but having a plurality of radially extending apertures extending there-through from a shallow groove 42 in its outer surface. The apertures include three relatively large apertures 43 and three relatively small apertures 44, this arrangement being more suitable for limiting incidence of "blow-back" than if all apertures are of the same size, since it results in uneven gas mixtures within the torch.
The radially extending apertures 43 and 44 are positioned slightly downstream of the downstream end of the primary mixing member 32, but the downstream end of the primary mixing member 32 is provided with a small projecting boss 46 which tapers towards the issue end when the apertures are opened with respect to the gas stream issuing from the primary mixing member, air is entrained with the gas stream as shown in Fig. 4.
: ' ':`
The other or downstream end of the air entrainment sleeve is threadably engaged by a secondary mixing member 48 of the gas mixing structure 31, the secondary mixing member 48 having a . . .
thread extending for most but not all of its length, and 5. the thread is interrupted intermediate its ends by a recess 49 so that an operator can quickly identify when the secondary mixing member has been unsc~ewed sufficiently for the air entrainment aperture 43 and 44 to be exposed. The air entrainment apertures are exposed on]y occasionally, that is lO. when the torch is required for heating of metal as distinct from welding of metal, and large areas of relatively low temperature gas are required to issue from the jet. NOrmally, however, the secondary mixing member is screwed hard against a tapered surface 50 which surrounds the boss 46 of the down-15. stream end of the primary mixing member, and a relatively large diameter central aperture within the member 48 pro~7ides a secondary mixing chamber designated 52.
Screwed on to the downstream end of the secondary mixing member 48 is a nozzle 53, the nozzle 53 having a bore 54 of 20. identica1 diameter to the diameter of the secondary mixing chamber 52, and the bore terminating in tapered walls 55 which terminate in an outlet jet aperture 56. The bore 55 of the nozzle 53, the inner walls of the jet aperture 56 and the bore of the secondary mixing chamber 52 are made as smooth 25. as possible, the smoother the better. In this embodiment the walls of the bore of the secondary mixing chamber 52 are burnished to achieve a high degree of smoothness. It has been found also that the length of the bore which is common to the .
::
', . - .- . .: , :
~065Z4Z
secondary mixing chamber and the upstre~m end of the nozzle should be related to its diameter, unless th~ bore is very long. However, for practical purposes it is desirable tha-t the bore be as short as possible, and should exceed eight times 5- the bore diameter. In this embodiment the bore length is 11.25 x the bore diameter, tha~ is, for a bore diameter of - 6.4 mm the bore length needs to be approximately 72 mm.
It has been found by experimentation that the bore length should be an odd mul~iple of 1.25 x the diameter and at 10. least 8.75 x the diameter to achieve the desired mixing condit-ions. If the bore is increased beyond the 11.25 x diameter of this embodiment, the criticality of its length progessively reduces, and results progressively improve, although the improve-ment is~ 80 slight that in most instances extended lengths are 15. not required. It is also found desirable to control the angle of convergence of the tapered walls 55 which define the end of the secondary mixing chamber bore, and in this embodiment the included cone angle is approximately 54 degress. It should range between 45 and 65 degrees, but the closer it is 20. taken to 54 degrees, the better the results are likely to be. This is believed to be related to the deflection of particles or molecules oE gas Erom the walls of the boreO
Again it has been found for reasons which are not under-stbod, that the jet diameter of the issuing aperture of the 25. nozzle is critical, and ~or any given torch, a series of experiments are required to ascertain which diameters are suitable. In the example of this embodiment, there have been three satisfactory diameters discovered, one being 0.90 millimeters, the second being 1.30 millimeters and the largest ~L0~5'~Z :~
being 2.40 millimeters, that is the same diameter as the diameter of the aperture through the oxygen director and the first mixing member. Diameters between these diameters -~
have been found to give results which are inferior.
In use, gas at low pressure (about 4 p.s.i. or 28 k.p.a.) is delivered at equal volumes to the torch, and not in the theoretically correct 80:32 ratio of oxygen to acetylene, but the flame temperature is extremely high for a very small diameter. A blue smooth cone extends for about nineteen mm.
in the case of the smallest tip, twenty nine mm. for the intermediate tip, and sixteen mm. for the large tip. If butane and oxygen are used then a 1-1 ratio by volume is found to work satisfactorily, but the temperature is much lower than with acetylene.
The primary combustion of the blue cone is known to yield carbon monoxide and hydrogen, and the secondary combustion of the surrounding flame to yield carbon dioxide and steam.
However, the surrounding flame is not oxygen-rich, and oxygen is entrained from the atmosphere by the smooth flowing gases to form the envelope flame. The quantity of entrained oxygen is very much greater than the prior art torches, and the welding takes place under such advantageous conditions that negligible metal oxidation occurs. This in turn simplifies welding of difficult metals such as aluminium and magnesium alloys.
The invention results in such improvements that micro-welding becomes possible, and in a second embodiment ; 1065Z4Z
(illustrated in Fig. 5) the construction is substantially similar to the first and similar numbers designate similar elements, excepting that instead of using a handle as in the first, the hand piece 11 comprises a gas directing block 5. 60 secured to one side, and near one end, of a mounting cylinder 61 which takes the place of the boss of the handle and which is threadably engaged by the oxygen director and by the primary mixing member. The block 60 is provided with two small flexihle tubes 62 to hose valves (not shown) 10. and the device can then be held between the fingers in the manner of a pencil. However, a simple tubular handle 63 is also provided which slips over the device and locks on to the cylindrical member 6 to provide a handle for hand welding if this is required.
;' , ':
:
Claims (11)
1. A welding torch comprising a hand piece, an oxygen conduit in the hand piece having connection means at its upstream end for connecting to an oxygen supply hose, and a tubular oxygen director at its downstream end, said tubular oxygen director being in gas flow communication with the conduit, a gas mixing structure comprising at least one mixing member which defines with the oxygen director, a primary mixing chamber, a combustible gas conduit in the hand piece having connection means at its upstream end for connecting to a combustible gas supply hose, and walls in the hand piece placing the downstream end of the gas conduit into gas flow communication with the primary mixing chamber, the gas mixing structure comprising a gas mixture directing aperture having a length exceeding its diameter, and walls defining a secondary mixing chamber of greater volume than the primary mixing chamber, a length which exceeds its diameter, and a diameter which exceeds that of said gas mixture directing aperture, and a discharge nozzle at the downstream end of said secondary mixing chamber, said oxygen director, primary mixing chamber, gas mixture directing aperture, secondary mixing chamber and nozzle all having a common polar axis.
2. A welding torch according to claim 1 wherein the gas mixture directing aperture walls are parallel, and the length of the aperture walls is at least five times greater than the aperture diameter.
3. A welding torch according to claim 1 wherein the tubular oxygen director has an aperture of diameter approx-imately equal to the diameter of the gas mixture directing aperture, the downstream end of the oxygen director aperture being spaced away from the upstream end of the gas mixture directing aperture by said primary mixing chamber.
4. A welding torch according to claim 1 wherein portion of the outer wall of said tubular oxygen director is tapered to converge towards its downstream end, and wherein the upstream end of said mixing member comprises a skirt surrounding said tapered wall portion, said skirt containing a plurality of radially extending apertures opening into an annular space surrounding said tapered wall portion, said gas flow communication between the gas conduit and the primary mixing chamber being through said radially extending apertures.
5. A welding torch according to claim 1 wherein said gas mixing structure comprises a second mixing member which is tubular and the walls of which surround said secondary mixing chamber, said secondary mixing chamber having a length which exceeds eight times its diameter.
6. A welding torch according to claim 5 wherein said hand piece contains a threaded aperture, and each of said tubular oxygen director, primary and secondary mixing members has an external thread, said oxygen director and primary mixing member threadably engaging said aperture, and a threaded sleeve threadably engaging a projecting end of said primary mixing member and connecting thereto the upstream end of said secondary mixing member.
7. A welding torch according to claim 6 wherein said threaded sleeve contains a plurality of relatively large apertures and a plurality of relatively small apertures extending therethrough in radial directions, the apertures being circumferentially spaced around the sleeve and arranged as air entrainment apertures for entrainment of air into said gas mixture when the upstream end of said secondary mixing member is spaced away from the downstream end of said primary mixing member.
8. A welding torch according to claim 1 further comprising respective swivel nuts on the upstream ends of the oxygen and gas conduits respective valves coupled to said swivel nuts, and hose unions on the inlet ends of the respective valves.
9. A welding torch according to claim 1 wherein said hand piece further comprises a handle, said oxygen and gas conduits both being contained within the handle.
10. A welding torch according to claim 1 wherein said hand piece comprises a mounting cylinder, a block secured on one side of the mounting cylinder and near one end thereof, said block containing said conduits, said gas mixing structure being coaxial with said mounting cylinder and carried thereby to project from the other end thereof.
11. A gas welding torch according to claim 10 further comprising a handle releasably engageable over said block and mounting cylinder.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| AUPC848376 | 1976-12-14 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1065242A true CA1065242A (en) | 1979-10-30 |
Family
ID=3766878
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA292,541A Expired CA1065242A (en) | 1976-12-14 | 1977-12-07 | Gas welding torch |
Country Status (3)
| Country | Link |
|---|---|
| JP (1) | JPS5824686B2 (en) |
| CA (1) | CA1065242A (en) |
| DE (1) | DE2755461A1 (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| AU535542B2 (en) * | 1979-08-29 | 1984-03-29 | Nicholas Thomas Edward Dillon | Welding and cutting handpiece |
| DE3904855A1 (en) * | 1989-02-17 | 1990-08-23 | Guenter Abele | Burner, in particular for the burning-off ramp of a hair-removing machine for slaughtered animals |
| DE202009018173U1 (en) | 2009-08-11 | 2011-03-17 | Kjellberg Finsterwalde Plasma Und Maschinen Gmbh | Nozzle cap and nozzle cap holder and arc plasma torch with the same and / or the same |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB425727A (en) * | 1934-05-07 | 1935-03-20 | Josef Jagfeld | Improvements in or relating to injector burners for autogenous metal working |
| CA961760A (en) * | 1971-12-30 | 1975-01-28 | Nicholas T. E. Dillon | Oxy-acetylene torches |
-
1977
- 1977-12-07 CA CA292,541A patent/CA1065242A/en not_active Expired
- 1977-12-12 JP JP52148280A patent/JPS5824686B2/en not_active Expired
- 1977-12-13 DE DE19772755461 patent/DE2755461A1/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5392356A (en) | 1978-08-14 |
| DE2755461C2 (en) | 1988-11-10 |
| DE2755461A1 (en) | 1978-06-15 |
| JPS5824686B2 (en) | 1983-05-23 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US4013227A (en) | Welding torch tip and method | |
| US5148986A (en) | High pressure thermal spray gun | |
| US4468007A (en) | Oxy cutting torch | |
| CA2333807C (en) | System for providing proximate turbulent and coherent gas jets | |
| EP0032151A1 (en) | Cutting torch having integral head mixer | |
| CA1065242A (en) | Gas welding torch | |
| US9149884B2 (en) | Universal head-mix swirl injector for gas torch | |
| EP2608924B1 (en) | Gas bolt heating apparatus | |
| US4409002A (en) | Utility torch having head mixer | |
| US3858808A (en) | Oxy-acetylene torches | |
| US8753111B2 (en) | Swirl combustion air fuel torch | |
| US4477262A (en) | Mixer for cutting torch | |
| US6063329A (en) | Mini welding/soldering torch | |
| US4275284A (en) | Gas-shielded arc welding torch | |
| US5540585A (en) | Self-igniting hand torches | |
| US5507438A (en) | Fuel gas and oxygen mixer for cutting torches | |
| US4798530A (en) | Nozzle assembly for hot air torch | |
| JPH0617736B2 (en) | Tip mixing type crater | |
| JP3156731B2 (en) | Quartz glass burner | |
| US4511086A (en) | Cutting torch | |
| US1970012A (en) | Welding torch | |
| WO2003010467A1 (en) | The gasoline and oxygen auto-igniting method of a hand-held cutting and welding gasoline torch, and its cutting and welding torch | |
| JP3058152U (en) | Burner | |
| RU2215623C1 (en) | Changeable nozzle to apparatus for gas-flame treatment of metals | |
| CA1215635A (en) | Mixer for cutting torch |