Oxy-acetylene welding rig

How it works

Granjon and Rosemberg, in their 1913 manual, describe the flame as the combustion of oxygen and acetylene in about equal volumes. The first stage forms hydrogen and carbon monoxide, which form the small white jet at the nozzle, and these burn to carbon dioxide and water vapor in the outer flame, drawing oxygen from the air. They state that the molten metal comes in contact only with the hydrogen and carbon monoxide of the first stage.

The torch regulates the mix. In the low-pressure blowpipes they illustrate, a jet of oxygen draws in the acetylene through a Giffard injector, so that the oxygen delivery fixes the power of the torch. Their text lists the first inventors of low-pressure torches as having feared that the flame would strike back into the acetylene tube.

The operator melts the edges of the joint with the flame and adds metal from a filler rod, without a separate heat source. The same gases are used to cut steel with the blowpipe, to which Granjon and Rosemberg devote a chapter; cutting has its own entry (see related).

Anatomy

Oxygen cylinder and regulator: Granjon and Rosemberg call the pressure regulator an oxygen reducing valve. OSHA requires that oxygen from a cylinder not be used without a regulator attached.
Acetylene cylinder and regulator: Acetylene is stored dissolved in acetone in a cylinder with a porous filler. Gáti and Kovács report that the porous mass takes about 25 percent of the cylinder volume.
Hoses: Miller says oxygen hose is green with right-hand threaded connections and fuel hose is red with left-hand threaded connections; T-grade hose can carry any fuel gas, while R- and RM-grade is for acetylene only.
Torch handle with valves: Valves for each gas. Miller refers to torch valves, and Granjon and Rosemberg mention needle valves on some blowpipes.
Mixer or injector: Draws or blends the acetylene with the oxygen. Granjon and Rosemberg describe the Giffard injector in low-pressure blowpipes.
Tip: The orifice of the tip is sized to the delivery of the injector; Granjon and Rosemberg say it must be neither reduced nor enlarged.
Reverse flow check valve or flashback arrestor: Miller states that check valves prevent backflow into the torch, hoses or regulator but do not stop flashback, which arrestors do; a system uses one or the other, not both.
Goggles with filter lenses: Required by OSHA for all gas welding.

Variants

Low-pressure injector blowpipe: Acetylene is drawn in by the oxygen jet. Granjon and Rosemberg illustrate a Fouché blowpipe of fixed delivery, so that five to ten blowpipes were needed to cover deliveries from about 50 to 75 liters per hour up to 2,000 to 2,500 liters per hour.
Low-pressure blowpipe with oxygen regulator (Picard pattern): The same text describes a Picard blowpipe in which the final regulation of the flame is by an oxygen regulator, and says this offers advantages over other low-pressure acetylene systems.
Medium and high-pressure blowpipes: Granjon and Rosemberg distinguish blowpipes using acetylene at high, medium and low pressure.
Dissolved acetylene or generator acetylene: Gas drawn from a cylinder, or from a generator in which calcium carbide is treated with water.
Cutting torch: The Science Museum Group holds an “S” type oxyacetylene torch for scrap cutting metal (accession 1933-91).
Multi-jet tip: The Science Museum Group holds a sectioned hand-held torch dated 1960–1970 with two interchangeable nozzles, a 0.5 millimeter burner and a six-hole multi-jet with a central oxygen-only jet.
Alternate fuels: Miller notes that propane and propylene can be used in place of acetylene with T-grade hose.

Specifications

Oxygen to acetylene volume ratio at the white jet · volumes: 1Granjon and Rosemberg: exactly one volume of oxygen to one volume of acetylene for the white welding jet; in practice a little more, about 1.2 to 1.4 to 1, in blowpipes that mix imperfectly.
Torch size (gas delivery) · liters per hour: Granjon and Rosemberg: from about 50 to 75 liters per hour for fine work up to 2,000 to 2,500 liters per hour for heavy work, in fixed-delivery blowpipes.
Maximum acetylene pressure · psig: 15OSHA 1910.253: acetylene shall not be generated, piped (except in approved cylinder manifolds) or used at more than 15 psig (30 psia). Miller’s setup example sets fuel gas delivery to 10 psig.
Flame temperature at the white jet · °C: Granjon and Rosemberg report Le Chatelier’s calculation of 4,000 °C (more than 7,000 °F) at the end of the white jet, and say the flame can melt lime, estimated to melt at 3,000 °C. No other figure was read.
Lens shade · shade number: OSHA 1910.252: shade 4 or 5 for light gas welding (to 1/8 inch), 5 or 6 for medium (1/8 to 1/2 inch), 6 or 8 for heavy (over 1/2 inch).

Made to

ISO 5172
ISO 9539
ISO 2503
ISO 5175-1
ISO 3821
NFPA 51
CGA E.4
OSHA 29-CFR-1910-253
AWS Z49.1

Safety and care

Safety

Do not use acetylene at more than 15 psig, and do not open an acetylene cylinder valve more than 1 1/2 turns, preferably no more than 3/4 turn, so that it can be shut quickly (OSHA 1910.253).
Keep cylinders, valves, regulators and hose free from oil and grease, and do not handle oxygen equipment with oily hands or gloves (OSHA 1910.253).
Open a cylinder valve slightly and close it before attaching a regulator, standing to one side of the outlet, and never crack a fuel-gas valve near sparks or flame (OSHA 1910.253).
Store oxygen cylinders at least 20 feet from fuel-gas cylinders or behind a noncombustible barrier at least 5 feet high (OSHA 1910.253).
Never use fuel gas from a cylinder through a torch with shutoff valves without a regulator (OSHA 1910.253).
Wear goggles or other suitable eye protection with filter lenses during all gas welding (OSHA 1910.252).
Install either reverse flow check valves or flashback arrestors, and test and replace them periodically (Miller).
Keep combustible material 35 feet from the work or shield it, and use a fire watch where required (OSHA 1910.252).

Care

Inspect hoses for worn or damaged areas before use and replace those with visible damage (Miller).
Check torch O-rings and seating surfaces, since damage can cause improper fits and gas leaks (Miller).
Do not enlarge or reduce the orifice of a tip (Granjon and Rosemberg).
Leak test connections with an approved leak-test solution or oil-free soap and water (Miller).

Tips

Look for the small white jet with a sharp edge
Granjon and Rosemberg set the standard for a regulated flame: a small white jet as large as possible provided its edges are sharp and clear, meaning there is no excess of acetylene. They state that excess acetylene carbonizes the metal and excess oxygen causes intense oxidation, and that the second defect is much more common.1
Keep the oxygen pressure as low as it will go
The manual says that a too rigid flame, which oxidizes the metal and sweeps the molten pool, is often due to too great a pressure of oxygen, and repeats that the oxygen pressure should be as low as possible.1
Tell the hoses by color and thread
Miller explains that oxygen hose is green with right-hand threads and fuel hose is red with left-hand threads, T-grade hose suits any fuel gas, but R- and RM-grade is acetylene only.1
Purge each gas through the torch before lighting
Miller advises opening the oxygen torch valve a quarter turn so gas passes for three to five seconds, setting the recommended pressure on the regulator while it flows, then closing the valve, and repeating the process for the fuel gas. The purpose is to purge the system and prevent a mixed-gas explosion. Tip charts in the torch manual give the pressure for each tip size.1
Open the oxygen cylinder slowly, then all the way
Miller says to open the oxygen cylinder valve slowly so the regulator pressurizes gradually, which reduces the heat of recompression, and then open it fully, because oxygen cylinders have double-seating valves and full opening prevents leaks and gives maximum flow.1
Check for leaks by soap or by pressure drop
Brush an approved solution or oil-free soap and water on connections and watch for bubbles. Another method closes the torch and cylinder valves and watches the regulator delivery pressure for a drop.1
Use soft iron filler and a flux on steel
Granjon and Rosemberg specify a soft iron wire, as far as possible Swedish iron of the first quality, free of phosphorus, sulfur and slag, for iron and mild steel. They recommend a flux that slags the oxide and note that braided rods had been abandoned because they offer a large surface for oxidation.1
Take the lens shade from the thickness of the work
OSHA lists shade 4 or 5 for light gas welding up to 1/8 inch, 5 or 6 for 1/8 to 1/2 inch and 6 or 8 above that. Where the torch produces a high yellow light, OSHA notes that a filter that absorbs the sodium line is desirable.1

History

Earliest documented

1901–1903 (see disputed)

France

Granjon and Rosemberg write that the first blowpipes working with acetylene under pressure were made in 1901 by MM. Fouché and Picard and that from 1903 oxy-acetylene welding was applied industrially. Gáti and Kovács credit Edmond Fouché with making the first injector-type acetylene-oxygen torch in 1903 with a Paris firm. Gas welding itself is older: Gáti and Kovács report a portable hydrogen apparatus built in France by Desbassayns de Richemont in 1838, named soudure autogène, which could join only lead.1 2

Gas welding depended on three separate achievements. Gáti and Kovács report that the hydrogen flame was first used to fuse lead in 1838, but that hydrogen and oxygen were both expensive. Edmund Davy found acetylene in 1836, Moissan and Wilson produced calcium carbide in 1892, and Le Chatelier told the Académie des Sciences in 1895 that acetylene burnt with equal parts of oxygen gave a temperature 1,000 degrees Celsius above the oxy-hydrogen flame. Linde’s production of oxygen from liquid air in 1895 made the second gas cheaper, according to Gáti and Kovács.

The torch was then made safe to operate. Gáti and Kovács write that Fouché developed a low-pressure acetylene torch in 1900 at the urging of an oxygen company and patented it in 1903, and that the Belgian Jottrand noticed in 1901 that flashback could be reduced by raising the speed of the escaping gas. Granjon and Rosemberg describe the Giffard injector in the Fouché torch, which draws acetylene with the oxygen jet, and say its early inventors feared flashback into the acetylene tube. Dates for the Fouché and Picard torches differ between the two accounts (see disputed).

Dissolved acetylene removed a hazard from the supply. Granjon and Rosemberg write that compressed acetylene is liable to decompose with violent explosions under heat or shock, that regulations forbade keeping it at more than a few pounds pressure, and that acetylene absorbed in acetone is absolutely safe. Gáti and Kovács date the Claude and Hess observation to 1897. OSHA’s current rule still limits acetylene to 15 psig in piping and use, and specifies how far a cylinder valve may be opened.

Gáti and Kovács state that gas welding, not electric arc welding, was the first fusion welding process used in industry, that it preceded coated-electrode arc welding, and that the latter spread widely only after 1930. Granjon and Rosemberg say the flame could melt lime, which they note could otherwise be done only in the electric arc, and describe repairs made in place, such as to the stem or rudder of a steamship. Hungary began training courses in autogenous welding in 1908.

Gáti and Kovács note that coated-electrode arc welding followed gas welding. Miller’s current instructions describe the equipment much as the 1913 manual does, with regulators, hoses and a torch, and add the check valves and flashback arrestors that prevent backflow and flame travel. Miller also notes that propane and propylene can replace acetylene with the correct hose.

Timeline

1836
Edmund Davy discovers acetylene, according to both Gáti and Kovács and Miller.1 2
1838
E. Desbassayns de Richemont of France builds a portable hydrogen apparatus whose flame fuses metals without added material; the process is named soudure autogène and is described in Polytechnisches Journal in 1840. Only lead could be joined, and the process was called lead soldering until the early twentieth century.1
1892
Moissan announces to the Académie des Sciences on 12 December the manufacture of calcium carbide, a discovery attributed to Moissan and the American Wilson.1
1895
Henri Le Chatelier reports to the Académie des Sciences that acetylene burnt with an equal volume of oxygen gives a temperature 1,000 °C higher than the oxy-hydrogen flame. In the same year Carl von Linde succeeds in producing oxygen from liquefied air.1 2
1897
Claude and Hess find that acetone dissolves acetylene, allowing it to be stored in cylinders with a porous filler.1 2
1901
The Belgian engineer Félix Jottrand finds that flashback in equal-pressure torches can be reduced if the outflow velocity of the combustible gas exceeds its ignition velocity. Granjon and Rosemberg date the first pressure-acetylene blowpipes of Fouché and Picard to the same year.1 2
1903
Fouché patents a low-pressure acetylene torch, reported in the same year to the German Acetylene Association; Granjon and Rosemberg date industrial application of oxy-acetylene welding from 1903.1 2
1908
The first course in autogenous welding for tradesmen begins in Hungary.1
1913
The translator’s preface to the third English edition of Granjon and Rosemberg’s manual is dated October 1913; the book describes the process as little more than twelve years old.1
1960–1970
A sectioned hand-held oxy-acetylene torch with two interchangeable nozzles is made; it is now in the Science Museum Group collection.1

Where the sources disagree

When and by whom was the oxy-acetylene torch developed?

The first blowpipes working with acetylene under pressure were made in 1901 by Fouché and Picard; the process has been applied industrially from 1903.1
R. Granjon and P. Rosemberg (translated 1913)
Edmond Fouché (1858–1931), a manager of the Compagnie Française de l’Acétylène Dissous, built the first injector-type acetylene-oxygen torch in 1903 with a Paris firm; elsewhere the same paper says he developed a low-pressure torch in 1900 and patented it in 1903.1
Gáti József and Kovács Mihály
Around the turn of the century a torch suitable for low-pressure acetylene was developed; no inventor is named, and the blow pipe or torch is introduced in 1887.1
Miller Electric

Gaps in the record (7)

The Fouché and Picard patents have not been located; the dates and the division of work between the two men rest on secondary books and a Hungarian paper.
Whether Fouché or Picard introduced the first oxygen regulator on the torch is not settled by the sources read.
The year of the Moissan communication is given by Granjon and Rosemberg; the date of Wilson’s work is not given in the sources read.
The date of the first dissolved-acetylene cylinder is given by Gáti and Kovács as 1897; Granjon and Rosemberg say “sixteen years ago” without a year.
The Science Museum Group torches are cataloged without a full description; their makers and exact dates of manufacture are not stated in the records read.
Typical tip sizes and pressures by plate thickness have not been sourced for specs; Miller refers to tip charts in torch manuals.
Standards (ISO 5172, ISO 9539 and others) have not been read.