CA2276924A1 - Cutting nozzle for a postmixed oxy-fuel gas torch - Google Patents
Cutting nozzle for a postmixed oxy-fuel gas torch Download PDFInfo
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- CA2276924A1 CA2276924A1 CA 2276924 CA2276924A CA2276924A1 CA 2276924 A1 CA2276924 A1 CA 2276924A1 CA 2276924 CA2276924 CA 2276924 CA 2276924 A CA2276924 A CA 2276924A CA 2276924 A1 CA2276924 A1 CA 2276924A1
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- nozzle
- torch
- cutting
- fuel gas
- bores
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Classifications
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- 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
- F23D14/42—Torches, e.g. for brazing or heating for cutting
-
- 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
- F23D14/46—Details, e.g. noise reduction means
- F23D14/48—Nozzles
- F23D14/52—Nozzles for torches; for blow-pipes
- F23D14/54—Nozzles for torches; for blow-pipes for cutting or welding metal
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E20/00—Combustion technologies with mitigation potential
- Y02E20/34—Indirect CO2mitigation, i.e. by acting on non CO2directly related matters of the process, e.g. pre-heating or heat recovery
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- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Gas Burners (AREA)
Abstract
A cutting nozzle for a postmixed oxy-fuel gas torch is described. The cutting nozzle is an integral body having a cylindrical shroud which surrounds and extends away from gas discharge orifices in a gas discharge end of the nozzle. The cutting nozzle has the advantage of producing a tighter gas stream and of promoting a more thorough mixing of preheat oxygen and fuel gas. The advantages include reduced machining time and material waste. The coupling of the nozzle to the torch is also facilitated and high quality performance of the cutting nozzle is promoted because alignment of the cutting nozzle in the torch head is ensured.
Description
CUTTING NOZZLE FOR A
POSTMIXED OXY-FUEL GAS TORCH
TECHNICAL FIELD
The present invention relates to oxy-fuel gas torches and, in particular, to a cutting nozzle for postmixed oxy-fuel gas torches.
BACKGROUND OF THE INVENTION
Oxy-fuel gas cutting torches are useful for cutting ferrous alloys. With the proper equipment, cuts can be effected through very thick billets. In operation, an oxy-fuel torch is used to direct an ignited stream of oxygen and fuel gas onto the surface of the metal to be cut. The metal is thus heated to its ignition temperature, at which point a stream of cutting oxygen directed at the surface oxidizes the heated metal to effect the cut.
The cutting torch may be one of a premixed or a postmixed type torch. In a premixed torch, preheat oxygen and fuel gas are mixed within the torch head before being discharged for ignition. In a postmixed cutting torch, the preheat oxygen and fuel gas are discharged from the torch in unmixed streams. Turbulence in the discharged streams mixes the oxygen and fuel gas before ignition occurs. A principal advantage of the postmixed cutting torch is that it is not subject to flashback, a potential hazard associated with the use of premixed torches. Flashback occurs when the oxygen and fuel gas mixture in a premixed torch ignites within the torch head. Postmixed torches are therefore preferred for heavy industrial applications where a torch is subjected to considerable heat. A further advantage of the postmixed torch is that postmixed nozzles produce a longer heat zone than premixed nozzles. This permits the postmixed torch to operate farther from the work, decreasing the heat stress on the torch and increasing the service life of the nozzle.
An example of a prior art postmixed oxy-fuel gas cutting torch and nozzle are taught in United States Patent No. 4,455,176 which issued to Fuhrhop on January 19, 1984. That patent describes a combination cutting torch and nozzle assembly for postmixed oxy-fuel cutting using two separate annular streams of preheat oxygen gas surrounding the fuel gas stream with the inner annular preheat oxygen stream directed to impinge the fuel gas stream very close to the point of discharge from the nozzle assembly. The nozzle assembly is secured to the head of the cutting torch by a hollow retaining nut which forms an annular gap with the nozzle assembly for discharging the outer preheat oxygen gas stream.
All prior art postmixed nozzles for oxy-fuel gas torches operate in substantially the same way. A
stream of cutting oxygen is discharged from an axial bore in the nozzle. A plurality of fuel gas discharge orifices arranged in a concentric ring around the axial bore discharge preheat fuel gas and a second plurality of gas discharge orifices arranged in an outer concentric ring discharge preheat oxygen which acts as an envelope that surrounds the fuel gas stream. As the gas streams flow toward the workpiece, a mixing of the fuel gas and the oxygen occurs and the mixture ignites to heat the workpiece.
Testing has shown that up to 50% of the preheat oxygen stream discharged from prior art postmixed torch nozzles is lost to the atmosphere before mixing with the fuel gas occurs. This contributes to inefficient combustion and slows the heating process. It also contributes to the cost of cutting since gases are not utilized to their potential. It has also been observed that prior art postmixed torch nozzles are incapable of effecting a parallel-sided cut through a thick workpiece.
The cut is narrower along a top of the workpiece (i.e.
close to the torch nozzle) than along a bottom of the workpiece. The thicker the workpiece, the wider the cut at the bottom side. If many thick billets must be cut, a significant loss of metal occurs.
A further disadvantage of prior art cutting nozzles for postmixed oxy-fuel gas torches is their direct exposure to splashback of molten metal from the cut. Splashback metal tends to stick to the discharge end of the nozzle, frequently blocking discharge orifices. When this occurs, the torch must be shut down to permit the nozzle to be cleaned or replaced. This interrupts workflow and increases operating expenses.
In order to overcome the disadvantages of the prior art, a novel cutting nozzle assembly for a postmixed oxy-fuel gas torch is disclosed in Applicant's Canadian Patent No. 2,109,772 which is entitled CUTTING
NOZZLE ASSEMBLY FOR A POSTMIXED OXY-FUEL GAS TORCH. This patent issued on April 20, 1999. The nozzle assembly described in this Canadian Patent includes a nozzle having passages extending from an intake end for receiving gases from the torch to a gas discharge end for discharging the gases. The nozzle assembly further includes a cylindrical shroud which surrounds and extends away from the gas discharge end of the nozzle to protect the discharge end of the nozzle from molten metal splashback and to concentrate, direct, and promote the mixing of oxygen/fuel gas streams. This results in a narrower, cleaner, more parallel-sided cut which conserves metal at the cut and increases the speed and efficiency of cutting. The service life of the nozzle is further increased because the discharge end of the nozzle is shielded from splashback.
The shroud is an integral part of a hollow retainer nut which is used for receiving the nozzle to couple the nozzle assembly to a torch head. The hollow retainer nut is usually produced from a cylindrical metal bar stock, which requires a certain quantity of materials to be removed from the metal stock to form a cavity of the hollow retaining nut. The material required to be removed and the machining time required to do so increases the manufacturing cost of the nozzle assembly.
The two-piece structure of the nozzle assembly also requires that the nozzle and the shroud be put together before the assembly can be coupled to the torch. In a mill or foundry environment where the cutting nozzles are used, the two-piece construction enables one piece to be separated from the other and lost. Furthermore, in the two-piece construction, an annular clearance must be left between the nozzle and the hollow retaining nut to permit the two pieces to be manually fitted together. This clearance may affect accurate alignment of the gas discharge passages of the nozzle with the shroud. As a result, the quality of performance of the nozzle may be compromised.
SUMMARY OF THE INVENTION
It is an object of the invention to provide a cutting nozzle which overcomes the disadvantages of the prior art.
It is another object of the invention to provide a cutting nozzle which has a unitary structure.
It is a further object of the invention to provide a cutting nozzle which performs well and is manufactured at a relatively low cost.
POSTMIXED OXY-FUEL GAS TORCH
TECHNICAL FIELD
The present invention relates to oxy-fuel gas torches and, in particular, to a cutting nozzle for postmixed oxy-fuel gas torches.
BACKGROUND OF THE INVENTION
Oxy-fuel gas cutting torches are useful for cutting ferrous alloys. With the proper equipment, cuts can be effected through very thick billets. In operation, an oxy-fuel torch is used to direct an ignited stream of oxygen and fuel gas onto the surface of the metal to be cut. The metal is thus heated to its ignition temperature, at which point a stream of cutting oxygen directed at the surface oxidizes the heated metal to effect the cut.
The cutting torch may be one of a premixed or a postmixed type torch. In a premixed torch, preheat oxygen and fuel gas are mixed within the torch head before being discharged for ignition. In a postmixed cutting torch, the preheat oxygen and fuel gas are discharged from the torch in unmixed streams. Turbulence in the discharged streams mixes the oxygen and fuel gas before ignition occurs. A principal advantage of the postmixed cutting torch is that it is not subject to flashback, a potential hazard associated with the use of premixed torches. Flashback occurs when the oxygen and fuel gas mixture in a premixed torch ignites within the torch head. Postmixed torches are therefore preferred for heavy industrial applications where a torch is subjected to considerable heat. A further advantage of the postmixed torch is that postmixed nozzles produce a longer heat zone than premixed nozzles. This permits the postmixed torch to operate farther from the work, decreasing the heat stress on the torch and increasing the service life of the nozzle.
An example of a prior art postmixed oxy-fuel gas cutting torch and nozzle are taught in United States Patent No. 4,455,176 which issued to Fuhrhop on January 19, 1984. That patent describes a combination cutting torch and nozzle assembly for postmixed oxy-fuel cutting using two separate annular streams of preheat oxygen gas surrounding the fuel gas stream with the inner annular preheat oxygen stream directed to impinge the fuel gas stream very close to the point of discharge from the nozzle assembly. The nozzle assembly is secured to the head of the cutting torch by a hollow retaining nut which forms an annular gap with the nozzle assembly for discharging the outer preheat oxygen gas stream.
All prior art postmixed nozzles for oxy-fuel gas torches operate in substantially the same way. A
stream of cutting oxygen is discharged from an axial bore in the nozzle. A plurality of fuel gas discharge orifices arranged in a concentric ring around the axial bore discharge preheat fuel gas and a second plurality of gas discharge orifices arranged in an outer concentric ring discharge preheat oxygen which acts as an envelope that surrounds the fuel gas stream. As the gas streams flow toward the workpiece, a mixing of the fuel gas and the oxygen occurs and the mixture ignites to heat the workpiece.
Testing has shown that up to 50% of the preheat oxygen stream discharged from prior art postmixed torch nozzles is lost to the atmosphere before mixing with the fuel gas occurs. This contributes to inefficient combustion and slows the heating process. It also contributes to the cost of cutting since gases are not utilized to their potential. It has also been observed that prior art postmixed torch nozzles are incapable of effecting a parallel-sided cut through a thick workpiece.
The cut is narrower along a top of the workpiece (i.e.
close to the torch nozzle) than along a bottom of the workpiece. The thicker the workpiece, the wider the cut at the bottom side. If many thick billets must be cut, a significant loss of metal occurs.
A further disadvantage of prior art cutting nozzles for postmixed oxy-fuel gas torches is their direct exposure to splashback of molten metal from the cut. Splashback metal tends to stick to the discharge end of the nozzle, frequently blocking discharge orifices. When this occurs, the torch must be shut down to permit the nozzle to be cleaned or replaced. This interrupts workflow and increases operating expenses.
In order to overcome the disadvantages of the prior art, a novel cutting nozzle assembly for a postmixed oxy-fuel gas torch is disclosed in Applicant's Canadian Patent No. 2,109,772 which is entitled CUTTING
NOZZLE ASSEMBLY FOR A POSTMIXED OXY-FUEL GAS TORCH. This patent issued on April 20, 1999. The nozzle assembly described in this Canadian Patent includes a nozzle having passages extending from an intake end for receiving gases from the torch to a gas discharge end for discharging the gases. The nozzle assembly further includes a cylindrical shroud which surrounds and extends away from the gas discharge end of the nozzle to protect the discharge end of the nozzle from molten metal splashback and to concentrate, direct, and promote the mixing of oxygen/fuel gas streams. This results in a narrower, cleaner, more parallel-sided cut which conserves metal at the cut and increases the speed and efficiency of cutting. The service life of the nozzle is further increased because the discharge end of the nozzle is shielded from splashback.
The shroud is an integral part of a hollow retainer nut which is used for receiving the nozzle to couple the nozzle assembly to a torch head. The hollow retainer nut is usually produced from a cylindrical metal bar stock, which requires a certain quantity of materials to be removed from the metal stock to form a cavity of the hollow retaining nut. The material required to be removed and the machining time required to do so increases the manufacturing cost of the nozzle assembly.
The two-piece structure of the nozzle assembly also requires that the nozzle and the shroud be put together before the assembly can be coupled to the torch. In a mill or foundry environment where the cutting nozzles are used, the two-piece construction enables one piece to be separated from the other and lost. Furthermore, in the two-piece construction, an annular clearance must be left between the nozzle and the hollow retaining nut to permit the two pieces to be manually fitted together. This clearance may affect accurate alignment of the gas discharge passages of the nozzle with the shroud. As a result, the quality of performance of the nozzle may be compromised.
SUMMARY OF THE INVENTION
It is an object of the invention to provide a cutting nozzle which overcomes the disadvantages of the prior art.
It is another object of the invention to provide a cutting nozzle which has a unitary structure.
It is a further object of the invention to provide a cutting nozzle which performs well and is manufactured at a relatively low cost.
,CA 02276924 1999-07-02 It is yet a further obj ect of the invention to provide a cutting nozzle which is easily and simply coupled to a torch without pre-assembly.
In accordance with the invention, there is provided a cutting nozzle for a postmixed oxy-fuel gas torch comprising an integral body which includes a first end for connection with an oxy-fuel gas torch, the first end having bores for cutting oxygen, fuel gas and preheat oxygen respectively; and a second end for discharging the cutting oxygen, fuel gas and preheat oxygen, the second end being surrounded by a shroud that extends away from the second end to promote a mixing action of the gases discharged from the nozzle and produce a gas stream that maintains its shape over a longer distance than a postmixed nozzle not having a shroud.
Preferably, the shroud includes a circular cylinder having an open end and a chamber defined by a side wall of the circular cylinder. The bores in the first end may include an axial bore for cutting oxygen, a first plurality of bores for fuel gas and a second plurality of bores for preheat oxygen, the first and second plurality of bores respectively surrounding the axial bore for cutting oxygen. All of the bores terminate in discharge orifices on the second end to discharge gases into the chamber to produce the mixed and longer gas stream.
The integral body of the nozzle preferably includes a helical thread that is adapted to engage a complementary thread in the postmixed oxy-fuel gas torch, and parallel flat surfaces that may be gripped by a wrench to couple the nozzle to the postmixed oxy-fuel gas torch or remove the nozzle from the torch.
The present invention therefore provides a unitary structure for a cutting nozzle for a postmixed oxy-fuel gas torch, the cutting nozzle having a shroud which extends away from the discharge end of the nozzle to protect the discharge end of the nozzle from molten metal splashback and to promote the mixing of the oxygen-fuel gas stream. The nozzle also includes a helical thread and gripping surfaces which are an integral part of the exterior of the nozzle body and used to couple the nozzle to the torch. The unitary construction of the nozzle reduces the machining time and material waste during the manufacture of the nozzle, so material and manufacturing costs are reduced. Moreover, an accurate alignment of the discharge passages of the - g -nozzle with the shroud is facilitated by the unitary construction and the quality of performance of the nozzle is ensured.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will now be more fully described by way of example only and with reference to the following drawings, in which:
FIG. 1 is a longitudinal cross-sectional view of a preferred embodiment of postmixed torch nozzle in accordance with the invention;
FIG. 2 is a top plan view of the postmixed nozzle shown in FIG. 1;
FIG. 3 is a longitudinal cross-sectional view of a second embodiment of a postmixed nozzle in accordance with the invention;
FIG. 4 is a top plan view of the postmixed nozzle shown in FIG. 3; and FIG. 5 is a partial cross-sectional view of the postmixed nozzle shown in FIG. 1 coupled with a postmixed cutting torch.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
FIG. 1 shows a longitudinal cross-sectional view of a cutting nozzle in accordance with a preferred embodiment of the invention. The cutting nozzle is an integral body, generally indicated by reference numeral 10, which includes a nozzle portion 12 having an intake end 14 adapted to be received in a nozzle seat of the postmixed oxy-fuel torch (see FIG. 5). The intake end 14 includes an axial bore 16 for cutting oxygen, a plurality of fuel gas bores 18 arranged in an inner concentric ring around the axial bore 16, and a plurality of preheat oxygen bores 20 arranged in an outer concentric ring around the axial bore 16. Each of the bores 16, 18 and 20 extends from the intake end 14 and terminates in a discharge orifice 22, 24 and 26, respectively, in a discharge end 28 of the nozzle portion 12.
A helical thread 30 is integrated with the exterior of the nozzle portion 12 and is adapted to engage a complimentary thread in the postmixed oxy-fuel gas torch (see FIG. 5). A hexagonal rib 32 is also integrated with the exterior of the nozzle portion 12 to provide a gripping surface for a wrench that may be used to couple the nozzle to the torch or remove the nozzle from the torch. A shroud 34 is an integral part of the of the body 10, which surrounds and extends in an axial direction away from the discharge end 28 of the nozzle portion 12 to an open end~36. The shroud 34 is preferably a circular cylinder or other cylindrical shapes may also be used. The sidewall of the shroud 34 defines a chamber 38 through which the gases discharged from the discharge orifices 22, 24 and 26 are mixed and channeled to produce a mixed gas stream which is maintained over a distance longer than a postmixed nozzle not having a shroud.
In accordance with this embodiment of the invention, the intake end 14 includes a central portion 40 surrounding the axial bore 16, two annular steps 42, 44 surrounding the respective inner and outer rings of the bores 18, 20, and tapered annular surfaces 46 which are adapted to be seated in a torch head having a tapered seat and circumferential gas discharge grooves (see FIG. 5).
FIG. 2 shows a top plan view of the cutting nozzle shown in FIG. 1. As is apparent, the hexagonal rib 32 of the nozzle portion 12 provides a gripping surface for a wrench to facilitate the coupling of the cutting nozzle to a torch. The shroud 34 surrounds the discharge end 28 of the nozzle portion 12. The discharge end 28 includes discharge orifices 22 for cutting oxygen, 24 for fuel gas and 26 for preheat oxygen. The discharge orifice 22 for cutting oxygen is preferably flared. This creates a swirl effect within the chamber 38 to promote the mixing of fuel gas and oxygen.
The shroud 34 also shields the discharge end 28 from molten metal splashed back from the cut. This enhances the service life of the nozzle because it substantially eliminates nozzle damage resulting from splashback metal contacting the nozzle and fusing with it.
FIG. 3 is a longitudinal cross-sectional view of a second embodiment of the invention. The cutting nozzle in FIG. 3 is very similar in structure to the cutting nozzle shown in FIG. 1. The cutting nozzle 10 is also an integral body 10 including a nozzle portion 12 and an integral helical thread 30, hexagonal rib 32 and a shroud 34 which surrounds and extends in an axial direction away from a discharge end 28 of the nozzle portion 12 to an open end 36 to form a discharge chamber 38. Unlike the embodiment shown in FIG. l, the nozzle portion 12 of this embodiment, has a flat intake end 14. An axial bore 16 and bores 18, 20, which respectively form an inner and outer ring, all extend from the flat intake end 14, terminating in orifices 22, 24 and 26 on the discharge end 28. The axial bore 16 has an intake region which has a slightly larger diameter than the rest of the bore for connecting with a respective gas passage in a torch head, not shown. The flared portion of the orifice 22 is longer and the flare angle is less than those of the embodiment shown in FIG. 1. While the flare is longer and the flare angle is less than that shown in FIG. 1, it should be appreciated that the performance is the same and the flares shown in FIGS. 1 and 3 are interchangeable. The bores 18 and 20 have a respective entrance portion defined by respective circumferential grooves which form distribution channels for the preheat oxygen and the fuel gas when the nozzle is installed in the torch head. This embodiment of the invention is adapted to be coupled to a oxy-fuel gas torch having a torch head with a flat seat.
The cutting nozzle of the integral body 10 is preferably constructed from brass alloy, although other materials such as copper, stainless steel and the like may also be used. The shroud 34 is preferably at least 0.65" (16.5mm~ long. Longer lengths may be used but much shorter lengths are not recommended. The thickness of the sidewall of the shroud 34 is preferably about 0.22"
(5.58mm) for good resistance to heat fatigue. A thinner sidewall may be used successfully, however, a sidewall of the shroud 34 of the second embodiment is preferably about 0.139" (3.53mm). At least the outer surface of the sidewall of the shroud 34 is preferably plated with chrome or nickel to inhibit the adhesion of molten metal splashback.
FIG. 5 shows the connection of the cutting nozzle, illustrated in FIG. 1, to a typical postmixed oxy-fuel gas torch. The oxy-fuel gas torch includes a torch head 50 which has a helical thread 52 on the interior to engage the helical thread 30 of the nozzle portion 12 for coupling the cutting nozzle 10 to the torch head 50. The torch head 50 is supported by a tubular handle 54. The tubular handle 54 is hollow.
Extending through the tubular handle 54 are supply tubes 56, 58 and 60 for respectively supplying cutting oxygen from an oxygen source, fuel gas from a fuel gas source, and preheat oxygen from the oxygen source. The fuel gas supply tube 58 and the preheat oxygen supply tube 60 are in fluid communication with circumferential distribution grooves 62 and 64, respectively. The circumferential distribution grooves 62 and 64 are defined on a tapered seat surface 66 on which the tapered annular surfaces 46 of the nozzle portion 12 are seated.
The coupling procedure and operation of postmixed oxy-fuel gas torches are well understood by those skilled in the art and will not be further described.
The embodiments described above are intended to be exemplary only. Changes and modifications to the specifically described embodiments may be made without departing from the scope of the invention, which is intended to be limited solely by the scope of the appended claims.
In accordance with the invention, there is provided a cutting nozzle for a postmixed oxy-fuel gas torch comprising an integral body which includes a first end for connection with an oxy-fuel gas torch, the first end having bores for cutting oxygen, fuel gas and preheat oxygen respectively; and a second end for discharging the cutting oxygen, fuel gas and preheat oxygen, the second end being surrounded by a shroud that extends away from the second end to promote a mixing action of the gases discharged from the nozzle and produce a gas stream that maintains its shape over a longer distance than a postmixed nozzle not having a shroud.
Preferably, the shroud includes a circular cylinder having an open end and a chamber defined by a side wall of the circular cylinder. The bores in the first end may include an axial bore for cutting oxygen, a first plurality of bores for fuel gas and a second plurality of bores for preheat oxygen, the first and second plurality of bores respectively surrounding the axial bore for cutting oxygen. All of the bores terminate in discharge orifices on the second end to discharge gases into the chamber to produce the mixed and longer gas stream.
The integral body of the nozzle preferably includes a helical thread that is adapted to engage a complementary thread in the postmixed oxy-fuel gas torch, and parallel flat surfaces that may be gripped by a wrench to couple the nozzle to the postmixed oxy-fuel gas torch or remove the nozzle from the torch.
The present invention therefore provides a unitary structure for a cutting nozzle for a postmixed oxy-fuel gas torch, the cutting nozzle having a shroud which extends away from the discharge end of the nozzle to protect the discharge end of the nozzle from molten metal splashback and to promote the mixing of the oxygen-fuel gas stream. The nozzle also includes a helical thread and gripping surfaces which are an integral part of the exterior of the nozzle body and used to couple the nozzle to the torch. The unitary construction of the nozzle reduces the machining time and material waste during the manufacture of the nozzle, so material and manufacturing costs are reduced. Moreover, an accurate alignment of the discharge passages of the - g -nozzle with the shroud is facilitated by the unitary construction and the quality of performance of the nozzle is ensured.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will now be more fully described by way of example only and with reference to the following drawings, in which:
FIG. 1 is a longitudinal cross-sectional view of a preferred embodiment of postmixed torch nozzle in accordance with the invention;
FIG. 2 is a top plan view of the postmixed nozzle shown in FIG. 1;
FIG. 3 is a longitudinal cross-sectional view of a second embodiment of a postmixed nozzle in accordance with the invention;
FIG. 4 is a top plan view of the postmixed nozzle shown in FIG. 3; and FIG. 5 is a partial cross-sectional view of the postmixed nozzle shown in FIG. 1 coupled with a postmixed cutting torch.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
FIG. 1 shows a longitudinal cross-sectional view of a cutting nozzle in accordance with a preferred embodiment of the invention. The cutting nozzle is an integral body, generally indicated by reference numeral 10, which includes a nozzle portion 12 having an intake end 14 adapted to be received in a nozzle seat of the postmixed oxy-fuel torch (see FIG. 5). The intake end 14 includes an axial bore 16 for cutting oxygen, a plurality of fuel gas bores 18 arranged in an inner concentric ring around the axial bore 16, and a plurality of preheat oxygen bores 20 arranged in an outer concentric ring around the axial bore 16. Each of the bores 16, 18 and 20 extends from the intake end 14 and terminates in a discharge orifice 22, 24 and 26, respectively, in a discharge end 28 of the nozzle portion 12.
A helical thread 30 is integrated with the exterior of the nozzle portion 12 and is adapted to engage a complimentary thread in the postmixed oxy-fuel gas torch (see FIG. 5). A hexagonal rib 32 is also integrated with the exterior of the nozzle portion 12 to provide a gripping surface for a wrench that may be used to couple the nozzle to the torch or remove the nozzle from the torch. A shroud 34 is an integral part of the of the body 10, which surrounds and extends in an axial direction away from the discharge end 28 of the nozzle portion 12 to an open end~36. The shroud 34 is preferably a circular cylinder or other cylindrical shapes may also be used. The sidewall of the shroud 34 defines a chamber 38 through which the gases discharged from the discharge orifices 22, 24 and 26 are mixed and channeled to produce a mixed gas stream which is maintained over a distance longer than a postmixed nozzle not having a shroud.
In accordance with this embodiment of the invention, the intake end 14 includes a central portion 40 surrounding the axial bore 16, two annular steps 42, 44 surrounding the respective inner and outer rings of the bores 18, 20, and tapered annular surfaces 46 which are adapted to be seated in a torch head having a tapered seat and circumferential gas discharge grooves (see FIG. 5).
FIG. 2 shows a top plan view of the cutting nozzle shown in FIG. 1. As is apparent, the hexagonal rib 32 of the nozzle portion 12 provides a gripping surface for a wrench to facilitate the coupling of the cutting nozzle to a torch. The shroud 34 surrounds the discharge end 28 of the nozzle portion 12. The discharge end 28 includes discharge orifices 22 for cutting oxygen, 24 for fuel gas and 26 for preheat oxygen. The discharge orifice 22 for cutting oxygen is preferably flared. This creates a swirl effect within the chamber 38 to promote the mixing of fuel gas and oxygen.
The shroud 34 also shields the discharge end 28 from molten metal splashed back from the cut. This enhances the service life of the nozzle because it substantially eliminates nozzle damage resulting from splashback metal contacting the nozzle and fusing with it.
FIG. 3 is a longitudinal cross-sectional view of a second embodiment of the invention. The cutting nozzle in FIG. 3 is very similar in structure to the cutting nozzle shown in FIG. 1. The cutting nozzle 10 is also an integral body 10 including a nozzle portion 12 and an integral helical thread 30, hexagonal rib 32 and a shroud 34 which surrounds and extends in an axial direction away from a discharge end 28 of the nozzle portion 12 to an open end 36 to form a discharge chamber 38. Unlike the embodiment shown in FIG. l, the nozzle portion 12 of this embodiment, has a flat intake end 14. An axial bore 16 and bores 18, 20, which respectively form an inner and outer ring, all extend from the flat intake end 14, terminating in orifices 22, 24 and 26 on the discharge end 28. The axial bore 16 has an intake region which has a slightly larger diameter than the rest of the bore for connecting with a respective gas passage in a torch head, not shown. The flared portion of the orifice 22 is longer and the flare angle is less than those of the embodiment shown in FIG. 1. While the flare is longer and the flare angle is less than that shown in FIG. 1, it should be appreciated that the performance is the same and the flares shown in FIGS. 1 and 3 are interchangeable. The bores 18 and 20 have a respective entrance portion defined by respective circumferential grooves which form distribution channels for the preheat oxygen and the fuel gas when the nozzle is installed in the torch head. This embodiment of the invention is adapted to be coupled to a oxy-fuel gas torch having a torch head with a flat seat.
The cutting nozzle of the integral body 10 is preferably constructed from brass alloy, although other materials such as copper, stainless steel and the like may also be used. The shroud 34 is preferably at least 0.65" (16.5mm~ long. Longer lengths may be used but much shorter lengths are not recommended. The thickness of the sidewall of the shroud 34 is preferably about 0.22"
(5.58mm) for good resistance to heat fatigue. A thinner sidewall may be used successfully, however, a sidewall of the shroud 34 of the second embodiment is preferably about 0.139" (3.53mm). At least the outer surface of the sidewall of the shroud 34 is preferably plated with chrome or nickel to inhibit the adhesion of molten metal splashback.
FIG. 5 shows the connection of the cutting nozzle, illustrated in FIG. 1, to a typical postmixed oxy-fuel gas torch. The oxy-fuel gas torch includes a torch head 50 which has a helical thread 52 on the interior to engage the helical thread 30 of the nozzle portion 12 for coupling the cutting nozzle 10 to the torch head 50. The torch head 50 is supported by a tubular handle 54. The tubular handle 54 is hollow.
Extending through the tubular handle 54 are supply tubes 56, 58 and 60 for respectively supplying cutting oxygen from an oxygen source, fuel gas from a fuel gas source, and preheat oxygen from the oxygen source. The fuel gas supply tube 58 and the preheat oxygen supply tube 60 are in fluid communication with circumferential distribution grooves 62 and 64, respectively. The circumferential distribution grooves 62 and 64 are defined on a tapered seat surface 66 on which the tapered annular surfaces 46 of the nozzle portion 12 are seated.
The coupling procedure and operation of postmixed oxy-fuel gas torches are well understood by those skilled in the art and will not be further described.
The embodiments described above are intended to be exemplary only. Changes and modifications to the specifically described embodiments may be made without departing from the scope of the invention, which is intended to be limited solely by the scope of the appended claims.
Claims (9)
1. A cutting nozzle for a postmixed oxy-fuel gas torch, comprising:
an integral body having a first end for connection with an oxy-fuel gas torch, the first end including bores for cutting oxygen, fuel gas and preheat oxygen respectively; and a second end for discharging the cutting oxygen, fuel gas and preheat oxygen, the second end being surrounded by a shroud that extends away from the second end to promote a mixing action of the gases discharged from the nozzle and produce a gas stream that maintains its shape over a longer distance than a postmixed nozzle not having a shroud.
an integral body having a first end for connection with an oxy-fuel gas torch, the first end including bores for cutting oxygen, fuel gas and preheat oxygen respectively; and a second end for discharging the cutting oxygen, fuel gas and preheat oxygen, the second end being surrounded by a shroud that extends away from the second end to promote a mixing action of the gases discharged from the nozzle and produce a gas stream that maintains its shape over a longer distance than a postmixed nozzle not having a shroud.
2. A cutting nozzle as claimed in claim 1 wherein the bores in the first end includes an axial bore for cutting oxygen, a first plurality of bores for fuel gas and a second plurality of bores for preheat oxygen, the first and second plurality of bores respectively surrounding the axial bore for cutting oxygen, all of the bores terminating in discharge orifices on the second end.
3. A cutting nozzle as claimed in claim 2 wherein the shroud comprises a circular cylinder having an open end and a chamber defined by a side wall of the circular cylinder.
4. A cutting nozzle as claimed in claim 3 wherein the integral body comprises a helical thread that is adapted to engage a complementary thread in a torch head of the postmixed oxy-fuel gas torch.
5. A cutting nozzle as claimed in claim 4 wherein the integral body includes parallel flat surfaces that may be gripped by a wrench to couple the nozzle to the postmixed oxy-fuel gas torch or remove the nozzle from the torch.
6. A cutting nozzle for a postmixed oxy-fuel gas torch, comprising:
an integral body having an intake end and a discharge end, the intake end being adapted to be received in a nozzle seat of the postmixed oxy-fuel torch a plurality of passages for respectively directing cutting oxygen gas, preheat oxygen gas and fuel from the torch to the discharge end of the nozzle body;
a helical thread for engaging a complementary thread in the postmixed oxy-fuel gas torch, and gripping surfaces for a wrench used to connect the nozzle to the torch, the helical thread and the gripping surface being formed integrally with an exterior of the nozzle body;
and a cylindrical shroud surrounding the discharge end, the shroud being an integral part of the nozzle body and extending in an axial direction away from the discharge end of the nozzle body to an open end to form a chamber having an axial extent adequate to promote a mixing action of the gases discharged from the passages and produce a gas stream that maintains its shape over a longer distance than a postmixed nozzle not having a shroud.
an integral body having an intake end and a discharge end, the intake end being adapted to be received in a nozzle seat of the postmixed oxy-fuel torch a plurality of passages for respectively directing cutting oxygen gas, preheat oxygen gas and fuel from the torch to the discharge end of the nozzle body;
a helical thread for engaging a complementary thread in the postmixed oxy-fuel gas torch, and gripping surfaces for a wrench used to connect the nozzle to the torch, the helical thread and the gripping surface being formed integrally with an exterior of the nozzle body;
and a cylindrical shroud surrounding the discharge end, the shroud being an integral part of the nozzle body and extending in an axial direction away from the discharge end of the nozzle body to an open end to form a chamber having an axial extent adequate to promote a mixing action of the gases discharged from the passages and produce a gas stream that maintains its shape over a longer distance than a postmixed nozzle not having a shroud.
7. A cutting nozzle as claimed in claim 6 wherein the passages include an axial bore through which cutting oxygen gas is discharged and spaced-apart gas discharge bores arranged in an inner and outer concentric ring around the axial bore, respectively, the bores in the inner ring being in fluid communication with a fuel gas conduit of the torch when the nozzle is coupled with the torch and the bores in the outer ring being in fluid communication with a preheat oxygen gas conduit of the torch when the nozzle is coupled with the torch, the axial bore and the gas discharge bores terminating in discharge orifices on the discharge end of the nozzle body.
8. A cutting nozzle as claimed in claim 7 wherein the intake end is a flat end having all of the bores therein, the intake end being adapted to be seated in a torch head having a flat seat.
9. A cutting nozzle as claimed in claim 7 wherein the intake end comprises a central portion having the axial bore, two annular steps having respective bores in the inner and outer rings, and tapered annular surfaces, adapted to be seated in a torch head having a tapered seat with circumferential grooves.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA 2276924 CA2276924A1 (en) | 1999-07-02 | 1999-07-02 | Cutting nozzle for a postmixed oxy-fuel gas torch |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA 2276924 CA2276924A1 (en) | 1999-07-02 | 1999-07-02 | Cutting nozzle for a postmixed oxy-fuel gas torch |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2276924A1 true CA2276924A1 (en) | 2001-01-02 |
Family
ID=4163687
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2276924 Pending CA2276924A1 (en) | 1999-07-02 | 1999-07-02 | Cutting nozzle for a postmixed oxy-fuel gas torch |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2276924A1 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2520560A (en) * | 2013-11-26 | 2015-05-27 | Linde Ag | Fuel gas cutting |
| CN112478584A (en) * | 2020-12-07 | 2021-03-12 | 蚌埠市维光塑胶制品有限公司 | Air cutting machine convenient for feeding and discharging and working method thereof |
-
1999
- 1999-07-02 CA CA 2276924 patent/CA2276924A1/en active Pending
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2520560A (en) * | 2013-11-26 | 2015-05-27 | Linde Ag | Fuel gas cutting |
| GB2520560B (en) * | 2013-11-26 | 2018-02-28 | Linde Ag | Fuel gas cutting |
| CN112478584A (en) * | 2020-12-07 | 2021-03-12 | 蚌埠市维光塑胶制品有限公司 | Air cutting machine convenient for feeding and discharging and working method thereof |
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| EEER | Examination request | ||
| FZDE | Dead | ||
| FZDC | Correction of dead application (reinstatement) |