0 items in your basket
Total £ 0.00 EX VAT
MIG Gloves
TIG Gloves
Baseball Caps
Armguards
TIG Heat Blockers
Shop 55,000 Products
SERVICEDEPT.
RAPID BLOG
FEEDBACK
HIRE
Answers to common questions about how injector mix cutting torches work, which fuel gases and nozzles to use, and how to use them safely.
In an injector torch, the preheat gases are mixed inside the torch body, gas tubes or head. The higher-pressure oxygen flows through an injector and draws the fuel gas in with it, so the fuel gas does not need to be supplied at the same pressure.In a nozzle mix torch the oxygen and fuel gas travel separately and only meet in the nozzle. Both types are used for steel cutting; the injector design is the one to look at when the fuel gas supply is at low pressure.
Because the oxygen does the work of drawing the fuel gas in, an injector torch can run on low fuel gas pressures and over long hose lengths. That makes it a common match for fuel gas supplies where the pressure is modest, and it suits workshop and site cutting where the hoses are long.The trade-off is that the oxygen supply pressure matters more, so the torch and nozzle must be set up to the maker's instructions. Do not mix parts between different torch types unless the maker says they are compatible.
It depends on the torch. Cutting torches are made for particular fuel gases, and some are suitable for one fuel only, while others cover several. Acetylene gives the hottest flame and pierces fastest, which suits thin sheet and short cuts. Propane pierces more slowly but tolerates a greater nozzle-to-work distance and usually leaves a smoother edge with less slag.The torch and the nozzle must both be marked for the fuel gas you intend to use, and each torch should be fitted with the nozzle intended for that fuel. If the markings or maker's data do not say so, do not assume it is suitable.
The cutting oxygen hole is chosen according to the thickness of the material, so thicker steel needs a larger bore. The type of nozzle also depends on the fuel gas, and on whether the cutting is done by hand or by machine.Use the torch maker's cutting chart for nozzle size, oxygen pressure and fuel gas setting. Fit only nozzles intended for your torch and fuel gas, and replace nozzles that are damaged or worn rather than trying to make them last.
Follow the torch maker's cutting chart for the nozzle you have fitted, as the correct settings depend on the nozzle size, the thickness of steel and the fuel gas. If the cutting oxygen pressure is too low, slag is not removed properly; if it is too high, the cut finish is poor and there is excess slag.For acetylene, the working pressure must not exceed 0.62 bar (9 psi) unless the equipment has been designed for a higher pressure. Use only regulators, hoses and torches that are made and marked for the gas concerned.
Cutting torches are made with different head angles, commonly a straight 180 degree head in line with the handle, and an angled head such as 90 degrees. An angled head is a common general-purpose choice for hand cutting, while a straight head can suit reach-limited work such as cutting in recessed areas, and is often used on machine set-ups.Choose according to how and where you cut: flat plate, awkward access, overhead or confined positions. Heads and nozzles are usually specific to a torch design, so check what fits the torch you are using and follow the maker's guidance.