Patent Application
20120139171
This application claims priority to Australian Patent Application 2010904831, filed Oct. 29, 2010. The above cited application is herein incorporated by reference as if fully set forth in its entirety.
This invention relates to the field of oxygen lances, particularly to the type used to open tapping holes in furnaces.
Oxygen lances are regularly used for a number of different purposes, from cutting metal objects such as beams and other structural members through to opening tapping holes in furnaces and crucibles.
The basic oxygen lance is a simple device that includes a metallic tube of around 4 m in length, and an oxygen supply. A supply of oxygen gas is continuously fed through the tube. Once the oxygen lance is ignited, the supply of oxygen sustains the continuous burning of the metal tubing. The result is a lance with an extremely high heat that is capable of melting and burning through a wide range of suitable objects. The metal tubing is consumed when the lance is in use, and therefore the lance needs to be fitted with fresh tubes at regular intervals to replenish the tubes as they are consumed by the use of the lance. A thermic lance operates in a similar way but includes wires (usually steel) inserted within the metallic tube to provide additional fuel for more heat generation.
One particular application of a lance is the use on furnaces to open tapping holes. Furnaces used in metallurgy run at very high temperatures. The refractory materials used to line the interior of these furnaces are capable of operating at these elevated temperatures, however specialised cooling panels are sometimes integrated into the furnace wall to extend the life of the refractory by conducting some heat away. Typically a furnace is fitted with a plurality of tapping holes which are used to tap molten metal in the furnace. When not in use, these tapping holes are blocked with a refractory mud or clay. This plug is inserted using a clay or mud gun or manually with a bot (clay plug wrapped in refractory fabric pushed in with a steel rod). The plug sets very hard and has a high resistance to heat. The plug of refractory clay and solidified metal then remains in place until the next tapping operation falls due, upon which the plug then needs to be removed.
One common way of removing the plugs is by burning through them using an oxygen lance. The tip of the lance burns at around 4,000° C., and is capable of burning through the refractory clay or mud plug material and the solidified metal in the tap hole. It is common for a lance to need to be fitted with 10 to 20 fresh tubes in order to open just one tapping hole. This means that the operation needs to be halted 10 to 20 times while the lance is withdrawn from the hole and a fresh tube attached. Each time the lancing operation is halted, the tap hole cools to some degree. The environment where this operation needs to take place is inherently dangerous given the extreme heat of the furnace being operated on, the extreme heat of the oxygen lance itself, and the presence of oxygen around molten metals. The need to regularly stop the operation, withdraw the lance, fit it with a fresh tube and then re-insert the lance into the tapping hole adds considerable time to the tapping operation, as well as increases the exposure of the lance operators to risk.
It is an object of the present invention to overcome, or at least ameliorate the aforementioned problems.
The present invention is an oxygen lance assembly that is at least capable of moving towards or away from the object to be lanced. The assembly includes a supply of gaseous oxygen and metallic tubing wherein the oxygen supply is continuously feed through the tubing when the lance is in use. The lance assembly includes a reel, and the metallic tubing is coiled upon and carried by the reel. When in use, the metallic tubing is continuously uncoiled from the reel as the metallic tubing is consumed during use of the lance.
Preferably the lance has a series of rollers that the metallic tubing passes through after it is uncoiled from the reel in order to straighten and guide the tubing.
Preferably at least one of the rollers in the series of rollers has adjustable means to adjust the straightening of the tubing.
Preferably the lance has a set of pinch rollers, and these rollers are capable of pulling on the tubing, and it is at least this pulling action that causes the metallic tubing to uncoil from the reel during use.
Preferably the rotation of the reel to uncoil the metallic tubing is powered by a motor, and the tubing is thereby forced through the series of straightening rollers by the powered uncoiling of the reel.
Preferably the tail end of the metallic tubing in one reel is connectable to the leading end of the metallic tubing in a subsequent reel so as to allow substantially continuous operation of the said lance as each reel of metallic tubing is consumed during use.
Preferably the tail end of the metallic tubing has a region of reduced diameter wherein the outer diameter of the said region is capable of being inserted into the inner diameter of the leading end of a new coil of metallic tubing such that when a reel of metallic tubing is consumed, the leading end of new reel of metallic tubing is slid over the region of reduced diameter so as to connect the ends of the metallic tubing together.
Preferably the reel is capable of accommodating a coil of metallic tubing that is at least 50 or 100 metres or more in linear uncoiled length, however in consideration of weight and handling requirements, the coils are typically in the range of 18 to 30 metres in linear uncoiled length.
Optionally the metallic tubing used in the lance includes additional fuel wires incorporated into the tube.
Preferably the lance is carried on a body that is suspended from a ceiling, and the body is movable in three dimensions.
Preferably the body contains strain gauges or similar features to provide feedback to the lance operators of the forward acting force being applied to the lance during operation.
Preferably the oxygen lance includes a shield to minimise the splash back of sparks and/or molten material erupting from the tap hole as it is being lanced. The shield is comprised of a planar sheet of suitable heat resistant material. The planar sheet includes a suitable notch or orifice that allows the metallic tubing of the lance to pass through the planar sheet.
Preferably the oxygen lance assembly includes a tap hole plugging tool. The tap hole plugging tool comprises of a shaft member that is removably fastenable to the oxygen lance assembly at one end, and the shaft extends in the direction of the metal tubing of the lance and has a plunger permanently attached at the opposite end of the shaft. The plunger being capable of holding a plug of suitable material for the tap hole, and the oxygen lance assembly with the plugging tool attached is then used to position and force the plug into position relative to the tap hole. In this arrangement the oxygen lance assembly is reconfigured to allow it to close a furnace tap hole.
Turning firstly to
The coil is either pulled from the coil using a pair of pinch rollers 11, or alternatively, the reel is coupled to an electric pneumatic or hydraulic motor which provides the torque required to turn the reel, or a combination of both the push of the motor and the pull of the pinch rollers 11 may be used in conjunction with one another. Optionally a set of guide rollers 37, or a guide rail (not shown) is attached to the reel to ensure that as the reel is turned by the electric motor, the metallic tubing is unable to simply unwind off the reel and not travel through the straightening rollers.
Turning to
An index motor 21 may be provided to move the lance assembly closer to, or away from the job to be worked on. Another motor 23 may be included to feed the tube off the reel during the use of the lance. This motor may be used in conjunction with a set of pinch rollers 11.
Before a cartridge of metallic tubing has been consumed, a new cartridge is placed upon the reel 5, and the trailing end of the preceding metallic tube is connected to the leading edge of the new cartridge of metallic tubing.
There is also an alternative method of joining the ends together. Instead of using a connector, either the lead end 27 of the metallic tubing from the new cartridge, or the trailing end 25 of the preceding metallic tubing may have a region that is of reduced diameter 35, as shown in
Turning to
Whilst the above description includes the preferred embodiments of the invention, it is to be understood that many variations, alterations, modifications and/or additions may be introduced into the constructions and arrangements of parts previously described without departing from the essential features or the spirit or ambit of the invention.
It will be also understood that where the word “comprise”, and variations such as “comprises” and “comprising”, are used in this specification, unless the context requires otherwise such use is intended to imply the inclusion of a stated feature or features but is not to be taken as excluding the presence of other feature or features.
The reference to any prior art in this specification is not, and should not be taken as, an acknowledgment or any form of suggestion that such prior art forms part of the common general knowledge in Australia.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2010904831 | Oct 2010 | AU | national |
