GB2520560A - Fuel gas cutting - Google Patents

Fuel gas cutting Download PDF

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Publication number
GB2520560A
GB2520560A GB1320822.8A GB201320822A GB2520560A GB 2520560 A GB2520560 A GB 2520560A GB 201320822 A GB201320822 A GB 201320822A GB 2520560 A GB2520560 A GB 2520560A
Authority
GB
United Kingdom
Prior art keywords
fuel gas
nozzle
passages
gas passages
fuel
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.)
Granted
Application number
GB1320822.8A
Other versions
GB2520560B (en
GB201320822D0 (en
Inventor
Glen Graydon
Walter Mark Veldsman
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Linde GmbH
Original Assignee
Linde GmbH
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Linde GmbH filed Critical Linde GmbH
Priority to GB1320822.8A priority Critical patent/GB2520560B/en
Publication of GB201320822D0 publication Critical patent/GB201320822D0/en
Publication of GB2520560A publication Critical patent/GB2520560A/en
Application granted granted Critical
Publication of GB2520560B publication Critical patent/GB2520560B/en
Expired - Fee Related legal-status Critical Current
Anticipated expiration legal-status Critical

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
    • F23D14/28—Burners for combustion of a gas, e.g. of a gas stored under pressure as a liquid in association with a gaseous fuel source, e.g. acetylene generator, or a container for liquefied gas
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K7/00—Cutting, scarfing, or desurfacing by applying flames
    • B23K7/08—Cutting, scarfing, or desurfacing by applying flames by applying additional compounds or means favouring the cutting, scarfing, or desurfacing procedure
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K7/00—Cutting, scarfing, or desurfacing by applying flames
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K7/00—Cutting, scarfing, or desurfacing by applying flames
    • B23K7/002—Machines, apparatus, or equipment for cutting plane workpieces, e.g. plates
    • 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
    • F23D14/20—Non-premix gas burners, i.e. in which gaseous fuel is mixed with combustion air on arrival at the combustion zone
    • F23D14/22—Non-premix gas burners, i.e. in which gaseous fuel is mixed with combustion air on arrival at the combustion zone with separate air and gas feed ducts, e.g. with ducts running parallel or crossing each other
    • 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
    • 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
    • F23D14/58—Nozzles characterised by the shape or arrangement of the outlet or outlets from the nozzle, e.g. of annular configuration
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23D—BURNERS
    • F23D2900/00—Special features of, or arrangements for burners using fluid fuels or solid fuels suspended in a carrier gas
    • F23D2900/00006—Liquid fuel burners using pure oxygen or O2-enriched air as oxidant

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • General Engineering & Computer Science (AREA)
  • Gas Burners (AREA)

Abstract

A method of cutting a metal workplace using fuel gas uses a nozzle 10 having an oxygen passage 11 and a plurality of fuel gas passages. Fuel gas is passed through one of the fuel gas passages 13, and another, different, fuel gas is passed through another fuel gas passage 12. The first and second fuel gases are burnt at the same time to heat the workpiece; and oxygen flows through a central passage to cut the heated metal. Preferably, the first fuel gas is acetylene and the second fuel gas is propane. The first and second gas passages 12, 13 may each comprise a plurality of passages, arranged in concentric rings around the central oxygen passage 11.

Description

Fuel Gas Cutting The present invention relates to a method of fuel gas cutting. In particular, the present invention relates to a dual fuel method of fuel gas cutting.
Fuel gas cutting technology for cutting steel plates is well known. In this process a fuel gas is used as a heat source to heat up the steel to be cut to a kindling temperature of about 900°C. A flow of oxygen gas is then directed at the heated steel. The hot steel in the path of the oxygen flow readily oxidises to form the cut.
It is well known that acetylene can be used economically for cutting steel thicknesses up to about 150mm, and that propane is more economic for thickness from about 150mm to about 1000mm. This is because acetylene has very high energy in the primary flame (about 1 8.9MJ/m3) which is ideal for reducing edge and piercing preheating time to hasten edge starting, piercing and cutting speed. Conversely, propane has most of its energy in the secondary flame (about 85.3 MJ/m3) which is ideal for heating operations for larger volumes of steel. Propane has much lower energy in its primary cones (about 10.4 MJ/m3) giving slow edge, piercing and cutting speeds.
The present invention provides a method of fuel gas cutting a metal workpiece, the method comprising: providing a nozzle having an oxygen passage and a plurality of fuel gas passages; supplying a first fuel gas through at least one of the fuel gas passages, and supplying a second fuel gas through at least one of the other fuel gas passages; com busting the first and second fuel gases at the same time to heat a metal workpiece; and providing a flow of oxygen through the oxygen passage to cut the heated metal.
The present invention is advantageous as it allows different fuel gases having different heating potentials to be used in a single step to heat a metal workpiece during a fuel gas cutting operation. This allows both time and cost to be saved by taking advantage of the properties of different fuel gases.
Preferably the first fuel gas is acetylene and the second fuel gas is propane, both of which are well known and readily available to the industry.
In a preferred example, the first fuel gas is supplied through a first plurality of the fuel gas passages, and the second fuel gas is supplied through a second plurality of the fuel gas passages. This allows the different effects of the different fuel gases to be distributed at the outlet end of the nozzle to achieve the best heating effects.
In a particularly preferred example, the first plurality of fuel gas passages are arranged equally spaced around a first circumference at an outlet end of the nozzle, and the second plurality of fuel gas passages are arranged equally spaced around a second circumference at the outlet end of the nozzle, wherein the first and second circumferences are arranged concentrically with respect to one another, and wherein the first circumference has a smaller diameter than the second circumference. This provides an arrangement in which the first fuel gas is burn as a ring within the second fuel gas.
Preferably the oxygen passage is located substantially at the centre of the nozzle.
In one preferred example, at least one of the fuel gas passages has a recess at the outlet end of the nozzle. This better allows for slow flame speeds.
Examples of apparatus suitable for carrying out the method according to the present invention will now be described with reference to the following Drawings in which: Figure 1 is a schematic sectional view of a prior art gas cutting nozzle in use cutting a steel plate; Figure 2a is a schematic sectional view of a dual fuel gas cutting nozzle; Figure 2b is a schematic plan view of the gas cutting nozzle of Figure 2a when viewed from line A-A in Figure 2a; Figure 3a is a schematic sectional view of an alternative high speed dual fuel gas cutting nozzle; Figure 3b is a schematic plan view of the gas cutting nozzle of Figure 3a when viewed from line B-B in Figure 3a; Figure 4a is a schematic sectional view of a further alternative dual fuel gas cutting nozzle; and Figure 4b is a schematic plan view of the gas cutting nozzle of Figure 4a when viewed from line C-C in Figure 4a; Referring to Figure 1, a prior art gas cutting nozzle 1 is shown. The nozzle 1 comprises a central passage 3 for the flow of the oxygen used in the cutting operation, and a plurality of circumferentially spaced fuel gas passages 2 through which a mixture of fuel gas and oxygen flows in use. The fuel gas passages 2 are equally spaced around the circumference of the nozzle 1 at equal radial distances from the centre of the nozzle 1. There are typically six to eight fuel gas passages 2 depending on the size of the nozzle 1. The nozzle 1 may typically be provided is sizes from 2mm -200mm as is standard in the industry.
In use, a fuel gas mixture comprising, for example, oxygen and acetylene or oxygen & propane, flows through the fuel gas passages 2 from the inlet end 8 of the nozzle 1 to the outlet end 9 of the nozzle 1. The fuel gas is combusted on exit from the nozzle 1 and forms flames 6 which heat the steel plate 4. To cut the steel plate 4, oxygen flows through the central passage 3 and oxides the hot metal of the steel plate to form the cut 5.
Figures 2a and 2b show a gas cutting nozzle 10 comprising a central passage 11 for the flow of the oxygen used in the cutting operation. As is conventional in the art, the central passage 11 comprises a constriction 14 which conditions the oxygen stream so that it is a substantially perfect cylindrical column of oxygen gas that is lamellar and non turbulent so that the cutting efficiency is very high so that high quality cuts can be achieved. The exit size is chosen for the material thickness being cut. The cutting oxygen gas flow rate is determined by the size of this exit..
A first ring of fuel gas passages 13 are circumferentially spaced at a first radial distance r from the centre of the nozzle 10, and a second ring of fuel gas passages 12 are circumferentially spaced at a second distance R from the centre of the nozzle 10. Wherein, the first distance r is smaller than the second distance R. The outlet ends of the second fuel gas passages 12 comprise recesses 17, which recesses are of greater diameter than the diameter of the second fuel gas passages 12.
The inlet end 18 of the nozzle 10 comprises a plurality of gas inlets 15, 16 and 20. The inlet 20 is for the oxygen which is used in the cutting operation. Inlets 16 facilitate the supply of oxy-acetylene gas to the first ring of fuel gas passages 13, and inlets 15 facilitate the supply of oxy-propane gas to the second ring of fuel gas passages 12.
As shown in Figure 2b, the first 13 and second 12 fuel gas passages are equally spaced around their respective circumferences. In this embodiment there are 6 first fuel gas passages 13 and six second fuel gas passages 12. It will be understood that any suitable number of fuel gas passages may be used.
In use, oxy-acetylene gas mixture flows along the first fuel gas passages 13 and oxy-propane gas mixture flows along the second fuel gas passages 12. The fuel gases combust on exit from the fuel gas passages at the outlet end 19 of the nozzle 10. The recesses 17 at the outlet ends of the second fuel gas passages 12 accommodate the fact that propane has a slower flame speed than acetylene (about 3.4mIs and 7.3m/s respectively).
The flames from the two different fuels therefore appear to sit" at equal distances from the outlet end 19 of the nozzle 10. This is vital as the propane flame will be unstable if the recess is not there.
The combustion of the dual fuel gases heat the steel before the oxygen flow through the central passage 11 oxidises the hot metal to form the cut.
The combustion of two fuel gases at the same time allows the superior heating capability of the propane to be harnessed whilst also benefiting from the superior edge starting, piercing speed and high speed capability of acetylene. Thicker sections of steel are thus able to be cut more quickly than with a solely propane fuelled torch.
Figures 3a and 3b show a high speed duel fuel gas cutting nozzle 30.
The gas cutting nozzle 30 is similar in all respects to the gas cutting nozzle 10 described above. However, in this example, the central passage 31 is provided with a convergent-divergent high speed nozzle 34. Such high speed nozzles are well known in the art.
Figures 4a and 4b show a further alternative duel fuel gas cutting nozzle 50. The nozzle 50 is made up of two separate sections, an inner section 58 and an outer section 57. The inner section 58 comprises a central passage 51 for the flow of oxygen used for cutting, and also a first ring of circumferentially spaced gas fuel passages 53. The outer surface of the inner section 57 comprises a plurality of machined teeth 56. In this example the teeth 56 have a substantially triangular cross-section. However it will be understood that any other suitable cross-section, such as rectangular of hemi-spherical, may be used.
The outer section 57 fits over and engages with the inner section 58 such that the outer section 57 engages with the apexes of the machined teeth 56. The juxtaposition of the inner section 58 with the outer section 57 forms a second ring of circumferentially spaced fuel gas passages 52.
As can be seen in Figure 4a, the outlet end 59 of the outer section 57 extends below outlet end 60 of the inner section, thus compensating for the different flame speeds between acetylene and propane.
The above described nozzles are examples only and it will be understood that the arrangement of fuel gas passages need not be limited to concentric arrangements of two rings. In particular, three or more rings of fuel gas passages may be provided and the fuel type delivered through any of the passages may be varied according to the desired end result. In addition, the fuel type need not be the same for all passages in any one ring. Finally, it will be understood that the arrangement of gas passages (when see in cross-section) need not be regular circumferential rings as described above, but may be provided in any suitable arrangement as desired, for example spiral or square.
Any type of fuel gas may be used and the invention is not limited to the fuel gases discussed above. In particular the fuel gases may comprise any two or more of any of the hydrocarbon fuel gas and/or methylacetylene.
Example fuel gases include: propane, propylene, methane, butane, butylene, butadiene, methy-acetylene, MAPP gas. LPG, and other proprietary fuel gas mixtures of the gases mentioned above.

Claims (7)

  1. Claims: 1. A method of fuel gas cutting a metal workpiece, the method comprising: providing a nozzle having an oxygen passage and a plurality of fuel gas passages; supplying a first fuel gas through at least one of the fuel gas passages, and supplying a second fuel gas through at least one of the other fuel gas passages; combusting the first and second fuel gases at the same time to heat a metal workpiece; and providing a flow of oxygen through the oxygen passage to cut the heated metal.
  2. 2. A method as claimed in claim 1, wherein the first fuel gas is acetylene and the second fuel gas is propane.
  3. 3. A method as claimed in any proceeding claim, wherein the first fuel gas is supplied through a first plurality of the fuel gas passages, and the second fuel gas is supplied through a second plurality of the fuel gas passages.
  4. 4. A method as claimed in claim 3, wherein the first plurality of fuel gas passages are arranged equally spaced around a first circumference at an outlet end of the nozzle, and the second plurality of fuel gas passages are arranged equally spaced around a second circumference at the outlet end of the nozzle, wherein the first and second circumferences are arranged concentrically with respect to one another, and wherein the first circumference has a smaller diameter than the second circumference.
  5. 5. A method as claimed in any proceeding claim, wherein the oxygen passage is located substantially at the centre of the nozzle.
  6. 6. A method as claimed in any proceeding claim, wherein at least one of the fuel gas passages has a recess at the outlet end of the nozzle.
  7. 7. A method of fuel gas cutting a metal workpiece substantially as described herein with reference to Figures 2a to 4b inclusive.
GB1320822.8A 2013-11-26 2013-11-26 Fuel gas cutting Expired - Fee Related GB2520560B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB1320822.8A GB2520560B (en) 2013-11-26 2013-11-26 Fuel gas cutting

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB1320822.8A GB2520560B (en) 2013-11-26 2013-11-26 Fuel gas cutting

Publications (3)

Publication Number Publication Date
GB201320822D0 GB201320822D0 (en) 2014-01-08
GB2520560A true GB2520560A (en) 2015-05-27
GB2520560B GB2520560B (en) 2018-02-28

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Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2328216A1 (en) * 1973-06-02 1974-12-19 Lotz Kg Gastechnik FLAME CUTTING WITH METAL POWDER
US4566676A (en) * 1982-06-26 1986-01-28 Lotz Horst K Short tip for a torch and a torch type tool
US4821963A (en) * 1986-07-30 1989-04-18 L'air Liquide Steelworks cutting nozzle with a double heating ring
US5535953A (en) * 1992-11-27 1996-07-16 Huehne; Erwin Injector tip for burning aggregates
CA2276924A1 (en) * 1999-07-02 2001-01-02 Oxy-Arc International Inc. Cutting nozzle for a postmixed oxy-fuel gas torch
US6277323B1 (en) * 1992-11-25 2001-08-21 Oxy-Arc International Inc. Cutting nozzle assembly for a postmixed oxy-fuel gas torch
KR100675495B1 (en) * 2005-05-19 2007-02-02 신중달 Cutting machine using gas
JP2011016155A (en) * 2009-07-09 2011-01-27 Nippon Steel Corp Method and device for gas-cutting cast slab

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2011103923A1 (en) * 2010-02-25 2011-09-01 Lotz Horst K Nozzle for cutting steel workpieces and workpieces made of iron alloys

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2328216A1 (en) * 1973-06-02 1974-12-19 Lotz Kg Gastechnik FLAME CUTTING WITH METAL POWDER
US4566676A (en) * 1982-06-26 1986-01-28 Lotz Horst K Short tip for a torch and a torch type tool
US4821963A (en) * 1986-07-30 1989-04-18 L'air Liquide Steelworks cutting nozzle with a double heating ring
US6277323B1 (en) * 1992-11-25 2001-08-21 Oxy-Arc International Inc. Cutting nozzle assembly for a postmixed oxy-fuel gas torch
US5535953A (en) * 1992-11-27 1996-07-16 Huehne; Erwin Injector tip for burning aggregates
CA2276924A1 (en) * 1999-07-02 2001-01-02 Oxy-Arc International Inc. Cutting nozzle for a postmixed oxy-fuel gas torch
KR100675495B1 (en) * 2005-05-19 2007-02-02 신중달 Cutting machine using gas
JP2011016155A (en) * 2009-07-09 2011-01-27 Nippon Steel Corp Method and device for gas-cutting cast slab

Also Published As

Publication number Publication date
GB2520560B (en) 2018-02-28
GB201320822D0 (en) 2014-01-08

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PCNP Patent ceased through non-payment of renewal fee

Effective date: 20201126