GB1570439A - Flame scarfing apparatus - Google Patents

Description

(54) FLAME SCARFING APPARATUS (71) We, I.P.U. LIMITED, a Bahamasnian Company, of 50 Shirley Street, Nassau, Bahamas, do hereby declare the invention for which we pray that a patent may be granted to us, and the method by which it is to be performed to be particularly described in and by the following statement:- The invention relates to a flame scarfing apparatus, more particularly for the aftertreatment of continuously cast steel, the device comprising: pipes for supplying fuel and oxygen to a nozzle; adjusting and shutoff valves for controlling the supply of fuel and oxygen; and an igniting bar device to produce the scarfing temperature.

Before continuously cast slabs can be given further treatment in rolling mills, it is the usual practice to remove the outer skin of the slab since it contains minor irregularities, such as small inclusions of slag. One way of removing the outer skin is flame scarfing, involving burning away the outer skin of the slab. The outer skin must therefore be preheated, then ignited, an excess of oxygen being supplied. Various portable devices are known for flame scarfing and there are also portable flame scarfing devices which are of similar construction to a cutting torch and which have shut-off valves and mixing valves. A disadvantage of portable flame scarfing devices is that their valves are often leaky and constitute a safety risk when it is considered that the device may be broken in the rough conditions which exist in blast furnaces and rolling mills, and breakage or destruction of the device may cause highly combustible gases to issue from it.

According to the present invention the above disadvantages are overcome by a flame scarfing apparatus comprising a portable device including three pipes constituting a frame for the portable device, a nozzle being connected to one end of the pipes, an ignition means being provided on the frame near the nozzle, a grip on the frame for both hands of an operating person and said apparatus carrying two normally open contact switches, a stationary supply device including three solenoid means, three on-off valve means controlled by said solenoid means, at least one of said on-off valve means being connected to an oxygen supply and another of said on-off valve means being connected to a fuel or hydrogen supply and three adjusting valve means, each one of the adjusting valve means being connected to one on-off valve means and controlling the possible flow rate of said oxygen or said fuel (hydrogen); a connecting device including three hoses each to connect one of said pipes to one on-off valve means and adjusting valve means, and an electrical cable to connect each said switch contacts to a said respective solenoid means.

Another advantage provided is that it is easier and simpler to manually operate the device than previously, weight and costs are reduced, since the special valve previously necessary can be omitted and no special castings to make up the device need be used, and stability is improved considerably since three pipes can provide considerable resistance to bending. The manually operated flame scarfing device must be relatively long because of the high scarfing temperature, so that there is a risk of the device sagging and vibrating; this risk must be reduced by rigid construction.

The invention will now be described with reference to the figures of the accompanying drawing in which: Figure 1 is a side elevation of a manually operated flame scarfing device, Figure 2 is a sectional view on the section station II-II of Figure 1, and Figure 3 is a schematic view showing adjusting and on-off valves used for the manually operated flame scarfing device of Figure 1.

Referring now to the drawing, a portable flame scarfing device (Figure 1) comprises three pipes 1, 2, 3 which extend parallel to one another and are disposed at the corners of an equilateral triangle shown in Figure 2.

The pipes have screwed connections 4, 5, 6 for hoses at the rear end and terminate at their front end in a mixing tube or nozzle 7.

The three pipes 1, 2, 3 form the frame of the portable flame scarfing device to which a hand lever 8, grip parts 9, 10 and an igniting device 11 are secured. Hand lever 8 is a double-armed lever, its longer arm 8a being adapted to be operated by the hand while the shorter arm 8b serves to move a rod 12 and initiate a restoring or return force through the agency of a helical spring 13. A four-core electric cable shown generally at 14 has four cores 14a, 14b, 14c, 14d and these together with three hoses 15, 16, 17 connect the back end of the portable scarfing device (Figure 1) to a stationary device 20 including at least an oxygen supply and a fuel or hydrogen supply as well as adjusting and on-off vaJves 2l, 22, 23, 24, 25 and 26 shown in Figure 2, the valves 24, 25, 26 being solenoid valves. Each of the cores 14a, 14b, 14c may be connected through a respective switch contact 19a, 18b and 18a to the core 14d, the contacts 18a, 18b belonging to a switch 18 which is actuated by the lever 8 and the contact 1 9a belonging to a switch 19 which can be actuated by hand when gripping the grip part 10.

The igniting device 11 is for feeding intermittently an igniting bar 30 to the nozzle opening 7. Correspondingly, the rod 12 has a pawl 31 engaging with a ratchet wheel 32 rotating only in the direction of an arrow 32a and through a predetermined distance.

The rotation is transmitted by way of an intermediate wheel 33 to a feed wheel 34, disposed opposite which is a pressing wheel 35. The bar 30 is clamped between the same and the feed wheel 34 and is therefore fed through or advanced at each operation of the lever 8.

The term "igniting bar" as used therein includes material in wire form which is supplied from a supply reel.

The operation of the apparatus described is as follows. First heating gas is used to preheat the workpiece to be scarfed. To this end, lever 8 is pivoted and switch 18 is operated, closing the contacts 18a, 18b. Therefore, cable cores 14b, 14c are connected to cable core 14d and the solenoid valves 25, 26 open, so that, depending on the setting of the valves 22, 23 hydrogen and oxygen go through the hoses 16 and 17 to the hose connections 5, 6 and thence to the pipes 2, 3 to produce a very hot flame at the nozzle 7.

To further increase flame temperature the flame is fed with metal in finely divided form as contained in the igniting bar 30. The resulting flame temperature increase is sufficient to ignite the metal of the slab (not shown) in the region being scarfed so that the temperature remains at the high level required. In order to burn the molten metal of the slab, further oxygen should be supplied. When switch 19 is closed, contact 19a bridges cable cores 14a and 14d, so that the circuit of the solenoid valve 24 closes and oxygen at a flow rate corresponding to the pre-setting of the valve 21 flows through hose 15 to hose connection 4 and thence to pipe 1 and, after passing through nozzle 7, burns the metal.

The switches 18, 19 are normally open contact switches, i.e. they open immediately after the manual operation ceases; consequently, simply releasing the device immediately interrupts the supply of gas in all three lines so that when the device is unused, the gas pipes are substantially empty.

Since hydrogen and oxygen are supplied simultaneously during flame scarfing, the two solenoid valves 25, 26 can be controlled through the agency of a common pair of cores, in which event the electric cable 14 need have only three cores. If required, the positions where the switches 18 and 19 are disposed can be changed over.

WHAT WE CLAIM IS: 1. A flame scarfing apparatus comprising a portable device including three pipes constituting a frame for the portable device, a nozzle being connected to one end of the pipes, an ignition means being provided on the frame near the nozzle, a grip on the frame for both hands of an operating person and said apparatus carrying two normally open contact switches, a stationary supply device including three solenoid means, three on-off valve means controlled by said solenoid means, at least one of said on-off valve means being connected to an oxygen supply and another of said on-off valve means being connected to a fuel or hydrogen supply and three adjusting valve means, each one of the adjusting valve means being connected to one on-off valve means and controlling the possible flow rate of said oxygen or said fuel (hydrogen); a connecting device including three hoses each to connect one of said pipes to one on-off valve means and adjusting valve means, and an electrical cable to connect each said switch contacts to a said respective

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (4)

**WARNING** start of CLMS field may overlap end of DESC **. station II-II of Figure 1, and Figure 3 is a schematic view showing adjusting and on-off valves used for the manually operated flame scarfing device of Figure 1. Referring now to the drawing, a portable flame scarfing device (Figure 1) comprises three pipes 1, 2, 3 which extend parallel to one another and are disposed at the corners of an equilateral triangle shown in Figure 2. The pipes have screwed connections 4, 5, 6 for hoses at the rear end and terminate at their front end in a mixing tube or nozzle 7. The three pipes 1, 2, 3 form the frame of the portable flame scarfing device to which a hand lever 8, grip parts 9, 10 and an igniting device 11 are secured. Hand lever 8 is a double-armed lever, its longer arm 8a being adapted to be operated by the hand while the shorter arm 8b serves to move a rod 12 and initiate a restoring or return force through the agency of a helical spring 13. A four-core electric cable shown generally at 14 has four cores 14a, 14b, 14c, 14d and these together with three hoses 15, 16, 17 connect the back end of the portable scarfing device (Figure 1) to a stationary device 20 including at least an oxygen supply and a fuel or hydrogen supply as well as adjusting and on-off vaJves 2l, 22, 23, 24, 25 and 26 shown in Figure 2, the valves 24, 25, 26 being solenoid valves. Each of the cores 14a, 14b, 14c may be connected through a respective switch contact 19a, 18b and 18a to the core 14d, the contacts 18a, 18b belonging to a switch 18 which is actuated by the lever 8 and the contact 1 9a belonging to a switch 19 which can be actuated by hand when gripping the grip part 10. The igniting device 11 is for feeding intermittently an igniting bar 30 to the nozzle opening 7. Correspondingly, the rod 12 has a pawl 31 engaging with a ratchet wheel 32 rotating only in the direction of an arrow 32a and through a predetermined distance. The rotation is transmitted by way of an intermediate wheel 33 to a feed wheel 34, disposed opposite which is a pressing wheel 35. The bar 30 is clamped between the same and the feed wheel 34 and is therefore fed through or advanced at each operation of the lever 8. The term "igniting bar" as used therein includes material in wire form which is supplied from a supply reel. The operation of the apparatus described is as follows. First heating gas is used to preheat the workpiece to be scarfed. To this end, lever 8 is pivoted and switch 18 is operated, closing the contacts 18a, 18b. Therefore, cable cores 14b, 14c are connected to cable core 14d and the solenoid valves 25, 26 open, so that, depending on the setting of the valves 22, 23 hydrogen and oxygen go through the hoses 16 and 17 to the hose connections 5, 6 and thence to the pipes 2, 3 to produce a very hot flame at the nozzle 7. To further increase flame temperature the flame is fed with metal in finely divided form as contained in the igniting bar 30. The resulting flame temperature increase is sufficient to ignite the metal of the slab (not shown) in the region being scarfed so that the temperature remains at the high level required. In order to burn the molten metal of the slab, further oxygen should be supplied. When switch 19 is closed, contact 19a bridges cable cores 14a and 14d, so that the circuit of the solenoid valve 24 closes and oxygen at a flow rate corresponding to the pre-setting of the valve 21 flows through hose 15 to hose connection 4 and thence to pipe 1 and, after passing through nozzle 7, burns the metal. The switches 18, 19 are normally open contact switches, i.e. they open immediately after the manual operation ceases; consequently, simply releasing the device immediately interrupts the supply of gas in all three lines so that when the device is unused, the gas pipes are substantially empty. Since hydrogen and oxygen are supplied simultaneously during flame scarfing, the two solenoid valves 25, 26 can be controlled through the agency of a common pair of cores, in which event the electric cable 14 need have only three cores. If required, the positions where the switches 18 and 19 are disposed can be changed over. WHAT WE CLAIM IS:

1. A flame scarfing apparatus comprising a portable device including three pipes constituting a frame for the portable device, a nozzle being connected to one end of the pipes, an ignition means being provided on the frame near the nozzle, a grip on the frame for both hands of an operating person and said apparatus carrying two normally open contact switches, a stationary supply device including three solenoid means, three on-off valve means controlled by said solenoid means, at least one of said on-off valve means being connected to an oxygen supply and another of said on-off valve means being connected to a fuel or hydrogen supply and three adjusting valve means, each one of the adjusting valve means being connected to one on-off valve means and controlling the possible flow rate of said oxygen or said fuel (hydrogen); a connecting device including three hoses each to connect one of said pipes to one on-off valve means and adjusting valve means, and an electrical cable to connect each said switch contacts to a said respective

solenoid means.

2. The apparatus according to Claim 1 further comprising a lever being arranged on the frame and to be actuated by hand carrying one of said switches, a rod connecting said lever and said igniting means, a pawl forming part of said igniting means, and an igniting bar, which is advanced when said pawl is moved when said lever is gripped.

3. The apparatus according to Claim 1 or 2, characterised in that the pipes of the frame are disposed, as seen in cross-section, at the corners of an equilateral triangle.

4. Apparatus constructed and arranged substantially as herein described and shown in the figures of the accompanying drawing.