IL33905A - Device for piercing holes by burning - Google Patents

Description

» A device for piercing holes by burning Dr. jur. Eduard LU3SER C: 3216? The invention relates to a device for "burning holes in concrete, "brickwork, stone, metal, or the like, comprising a metallic gas rod, which has at least one due extending therethrough and is connected at one end with a source of oxygen under high pressure.

Devices of this kind are already known. They are often called thernic lances and up until now usually consisted of a thick-walled iron or steel pipe having wires of iron or steel or sometimes magnesium mounted in the hollow interior of the pipe. The oxygen is "blasted through with an excess pressure of about J.5 to 25 atmospheres and the front end of the pipe is heated, for example with a welding torch, until the pipe begins to burn under the effect of the oxygen itself. The burning pipe is now pressed against the material for .example concrete in which a hole is to be formed. Heating causes the metal to melt and the iron oxides in concrete and stone set off chemical reactions which give rise to lower melting points so that the material flows out in the form of a liquid lava.

The holes produced by this combustion boring- are always round, to correspond with the shape of the combustion pipe or gas rod. If longitudinal cuts are to be produced, as for cutting out a door opening in a concrete wall, then several holes each linked to the next, are cut until the entire periphery of the part to be cut out is separated.

The costs involved in this method are usually higher than for carrying out the same work by means i r elec ric drills. The combustion borin . method was therefore previously used only where its lack of noise, vibration and dust were considered as great advantages, or where for technical reasons the use of pneumatic or electric drills was out of the question.

The present invention aims to produce a gas rod "by which the costs for any particular piece of work can he reduced to a fraction of those incurred for the same work with a pipe of the type known up until now. . A particular advantage occurs with the cutting of longer slits, which is the type of work for which combustion boring is used in over 95% of all cases in the building industry. i'he invention accordingly provides a gas rod for burning holes in concrete, brickwork, stone, metal or the like, the rod being of metal and having one or more ducts extending therethrough for the passage of oxygen from a source of oxygen under pressure connected at one end of the rod, the or each duct, having a slit-like cross-section such that the length of the slit . is a multiple of the v/idth of the slit, and the bulk of the material of the rod being located at the longer sides of the cross-section.

Seen in cross-section, in the device according to the invention, the hollow interior of the gas rod through which the oxygen is passed can be an oblong slit with the length of the slit a multiple of the width thereof and the bulk of the rod material seen in this same cross-section defining the two longer sides of the slit.

This slit-like design of the through-flow orifice for the oxygen results in preferential expansion ox the oxygen whic eraerges from the slit in the direction in which the bulk of the rod material lies, so that the molten iron is carried along in the form of sparks or drops in both directions at right angles to the longer axis of the slit and spun onto the concrete or other material to be melted. With a suitable design of the rod, this enables the material to decompose in the shape of an ellipse;, the major axis of which runs at right angles to the longer axis of the slit.

Further details and advantages of the invention will now be explained with reference to the accompanying drawing in which: Figure 1 is a perspective view including a cross-section of. a first gas rod embodying the invention; Figure 2 is a cross-section through a second gas rod embodying the invention, showing the cross-section area of the hole produced thereby; and Figure 5 is a cross-sectional view through a third gas rod embodying the invention, the rod comprising three profiled bars.

The gas rod illustrated in Figure 1 consists of two iron bars 1 , 2 of rectangular cross-section which are connected together, as by resistance welding, oyer two strips of sheet iron 3, 4- inserted between them for . the purpose of forming a slit-like duct 5 fo the passage of oxygen. The duct 5 must be formed so that its length in cross-section c is a multiple of its width h (see Figure 2 Figure 2 is a cross-section through a gas rod which is welded together from two bars 6, 7> each comprising three profiled oars 8,9,10 and having two ducts 5 providing curved slits in cross-section which are of symme rical arcuate shape.

The oblong, slit-like shape of the ducts 5 carrying the oxygen affords control and concentration of the powerful radiating sparks of the molten iron in a desired direction. The cross-section whic is burnt out to form the hole takes the shape of an ellipse 11, as indicated in Figure 2. Cutting a section in a concrete wall by burning out a line of oval holes is more economical the smaller the minor axis b of an ellipse 11 is in comparison to the major axis thereof, in that less material must be burnt . out across the cutting direction. A gas rod of the type illustrated in Figure 5 having two ducts 5 forming curved slits has an improved effect since the curvature of the slits causes an additional concentration of the radiating sparks in the directions of largest cross-section of the rod material, that is upwards and downwards as shown in the drawing.

The advantages achieved by the new gas rod in comparison with the hitherto usual type of gas rod, having a round cross-section with wire filling, will now be explained with reference to an example.

A window, for example, of 1 nt x m_, correspondin to a cut of 400 cm long, is to be cut out from a concrete' wall. If this work is carried out with a round gas rod of the type previously used and having an outer diameter of for example .17 £_m and filled with wire, whereby a round hole of about 0 mm diameter can.be burnt, then SO holes with a total surface area of 157.000 mm must be "burnt. The volume- of concrete burnt out corresponds to this area times the thickness of the concrete wall'.

The cost of the work arises from the amount of iron to be liquified, the ■oxygen used to do this and the working time involved. The costs are thus approximately-proportional to the volume or- surface area of the concrete to be burnt out.

If now the same work is carried out with a gas rod according to Figure 1 or 2 and which is 17 M long in section and 8 mm wide with a duct of 11 x 0.5 Est cross-sectional dimensions, an elliptical hole, 50 τ^η. long but only 20 mm wide can be produced. Thus for the same work, 80 holes again have to be burnt, but their 2 surface area amounts to only " Q.^OO mm , thus approximately half the previous figure, whereby a corresponding reduction in costs is achieved...

However, this is only a part of the technical advancement achieved. It has been shown that less iron and oxygen is consumed for burning out a specific volume of concrete with the new gas rod than with a round, ipe filled with wire. This can be explained in that with such a pipe, the oxygen emerges from many small outlet orifices and sprays out in practicall all directions. A large part -of the molten iron in spark and drop form is therefore not directed with .the full kinetic energy against the concrete wall to' be dealt with. The energy is partly consumed by mutual collisions of the particles. As opposed to this, with a as rod havin slit-like ox en channels without an wires, practically the entire kinetic energy of the molten iron particles in spark and drop form is used to decompose the concrete.

In addition, the production costs of for example a gas rod according to Figure 1 are lower than those of the pipe filled with wires 'hitherto usual. or this reason, the total costs for carrying out a specific job are reduced to a fraction of the costs incurred at present.

The new gas rod offers other advantages.

Since the holes which, are burnt out have an elliptical cross-section, it is possible for example in order to produce an anchor in a concrete wall to. first burn an elliptic hole of a certain depth with a vertical main axis and turn the gas rod through 90° , thereby attaining an elliptic hole at this depth with a horizontal main axis. In this way, oblong anchor plates can be inserted in.the bore and secured by rotation through 90°. An anchor of this type can accommodate much higher tensile stresses than one set by concrete in a round hole. · 33905/2

Claims (6)

1. A thermic lance for burning holes in concrete, brickwork, stone, or metal, the lance being of metal and having along the entire length thereof one or more ducts for conducting oxygen under pressure from one end of the lance to the other, the cross-sectional shape of the lance being the same along the entire length thereof, the cross-section of the duct or ducts having the shape of a narrow slot of which the length is a multiple of the width, and the thickness of metal between the internal and surfaces of the lance and the thickness of the solid portions between the slots being greater in the direction of the width of the slot than in the direction of the length thereof.

2. A thermic lance as claimed in Claim 1 formed from two bars of rectangular or square cross-section and two side members spacing the bars apart to define the duct therebetween.

3. A thermic lance as claimed in Claim 1 formed from two profiled bars shaped to define the duct therebetween.

4. thermic lance as claimed in Claim 3 formed from the two profiled bars and at least one additional profiled bar and having a plurality of the ducts.

5. A thermic lance as claimed in Claim 3 having an additional profiled bar and a pair of ducts, the ducts having like arcuate cross-sections positioned with the convex sides of the ducts adjacent.

6. A thermic lance as claimed in Claim 1, 3 or 4 in which the cross-section of the or each duct is curved, undulated, zig-zag shaped or divided into a plurality of parts. For the Applicant DR. REINHOLD COM AD PARTNERS