BLOW TORCH, A BLOW TORCH NOZZLE AND A SWIRLER FOR A BLOW TORCH NOZZLE

Abstract

A blow torch nozzle (10) having a swirler (26) which is bounded by a generally cylindrical shape (42). The swirler (26) a passageway (28, 40) extending through it defined by a wall surface of the swirler (26). A part of the wall surface extends at an angle to the axis of the nozzle (10) to impart a rotary motion to gases which pass through the swirler (26) in use. The wall surface opens out onto a side of the swirler (42) so the wall surface defines a recess (28, 40) extending inwardly from the side of the swirler (26). The swirler (26) may be provided with a short tube or ring (50) which surrounds the swirler (26) and has ends which are substantially flush with those of the swirler (26). The swirler (26) may be held within the tube or ring (50) by means of an interference fit.

Claims

1. A blow torch nozzle having a swirler within it which swirler is bounded by a generally cylindrical shape and which swirler has at least one passageway extending through it defined at least in part by a wall surface of the swirler at least a part of which wall surface extends at an angle to the axis of the nozzle so as to impart a rotary motion to gases which pass through the swirler when the blow torch is in use, in which the wall surface opens out onto a side of the swirler in such a manner that the wall surface defines a recess extending inwardly from the side of the swirler.

2. A blow torch nozzle according to claim 1, in which the swirler comprises a replaceable component of the blow torch nozzle.

3. A blow torch nozzle according to claim 1, in which the swirler has a plurality of such passageways, for example four.

4. A blow torch nozzle according to claim 1, in which side surfaces of the swirler and each wall surface of the or each passageway may be such that they are generated, in a mathematical sense, substantially by edges of one of the end surfaces of the swirler as it is moved axially along the swirler to the other end thereof, and rotated as it is so moved, the movement and the rotation being at a substantially uniform rate.

5. A blow torch nozzle according to claim 4, in which the angle of such rotation from one end of the swirler to the other is substantially 45 degrees.

6. A blow torch nozzle according to claim 1, in which the swirler is provided with a cylindrical ring which surrounds the swirler, and is secured thereto, for example by swaging.

7. A blow torch nozzle according to claim 6 in which the swirler is held within the ring by means of an interference fit.

8. A blow torch nozzle according to claim 6, in which the ends of the swirler are substantially flush with the ends of the ring.

9. A blow torch nozzle according to claim 1, in which the nozzle comprises two tubular parts connected together by respective screwthreads of those parts so that those parts have a common axis, those parts having respective internal shoulder portions between which the swirler or the ring thereof is held.

10. A blow torch nozzle having a swirler within it which swirler is bounded by a generally cylindrical shape and which swirler has at least one passageway extending through it defined at least in part by a wall surface of the swirler at least a part of which wall surface extends at an angle to the axis of the nozzle so as to impart a rotary motion to gases which pass through the swirler when the blow torch is in use, in which in any and every cross-section of the nozzle that includes the swirler, the said wall surface is generally U-shaped or arcuate, and the said at least one passageway is also defined on its outerside by a part cylindrical surface of the swirler which is everywhere at a substantially uniform distance from an outer cylindrical surface of the swirler.

11. A blow torch having a nozzle as claimed in claim 1.

12. A swirler for a blow torch nozzle having the features of the swirler as set out in claim 1.

Description

[0016] Examples of a blow torch nozzle and a swirler for a blow torch nozzle in accordance with the present invention will now be described in greater detail with reference to the accompanying drawings, in which:

[0017] FIG. 1 shows an exploded view of a first embodiment of a blow torch nozzle in accordance with the present invention;

[0018] FIG. 2 shows an exploded axial sectional view of two parts of the nozzle shown in FIG. 1;

[0019] FIGS. 3 and 4 show side and end views respectively of a swirler of the nozzle shown in FIGS. 1 and 2;

[0020] FIG. 5 shows an exploded axial sectional view of a two parts of a second embodiment of a blow torch nozzle in accordance with the present invention;

[0021] FIGS. 6 and 7 show end and side views respectively of a swirler of the nozzle two parts of which are shown in FIG. 5; and

[0022] FIG. 8 shows an exploded view of a third embodiment of a blow torch nozzle in accordance with the present invention.

[0023] The blow torch nozzle 10 shown in FIGS. 1 to 4 comprises two tubular metal parts 12 and 14. The two parts when assembled are screwed together by way of an external screwthread 16 on a lower one of the parts 14, and an internal screwthread 18 on an upper one of the parts 12. The outer surface of the upper part 12 tapers towards its upper end. The lower part 14 is also provided with an internal screwthread by which it is secured to a blow torch pipe 20.

[0024] The parts 12 and 14 have respective internal shoulders 22 and 24 between which are sandwiched a swirler 26. This comprises a cylindrical block of metal into the sides of which are cut five slots 28 uniformly spaced around the axis of the swirler 26. Each slot 28 extends from the bottom 30 to the top 32 of the swirler 26 at an angle to the axis thereof, the angle being in the range from 10 degrees to 45 degrees, in this case about 20 degrees. The inner surface of each slot in section is generally U-shaped. In successive cross-sections of the swirler 26 progressing from its top to its bottom, the U-shape of each passageway rotates progressively through an angle of about 70 degrees.

[0025] These aspects of the swirler 26 provide the characteristics of the first aspect of the present invention.

[0026] The second embodiment shown in FIGS. 5 to 7 differs from that shown in FIGS. 1 to 4 in that the swirler 26 has a greater depth, and this is accommodated by having the shoulder 24 of the lower part 14 further away from the upper end of that part. The externally screwthreaded portion thereof is also longer.

[0027] The swirler of the second embodiment has four recesses 40 formed in its sides instead of the five slots of the first embodiment. The top end 32 has a generally cruciform shape which has four arcuate ends 42 lying on an imaginary cylinder, and four arcs 44 each extending between two adjacent ends 42 and uniformly spaced around the axis of the swirler. The bottom end 30 has the same shape as the top end 32, but as viewed along an axial direction of the swirler is rotated relative to the top end 32 by substantially 45 degrees. The interior surfaces of the swirler defining the recesses 40, and the external cylindrical surfaces of the swirler, are generated in a mathematical sense substantially by edges of one of the end surfaces of the swirler as it is moved axially along the swirler to the other end thereof, and rotated as it is so moved, the movement and the rotation being at a substantially uniform rate.

[0028] In the embodiment shown in FIG. 8, the swirler 26 has the same construction as shown in FIGS. 6 and 7, but it is of slightly smaller diameter (or alternatively the internal diameters of the parts 12 and 14 are slightly greater) to accommodate a short cylindrical brass tube or ring 50 which surrounds and into which fits the swirler 26, the tube or ring 50 and the swirler 26 being held together by swaging around the centre of the tube or ring 50 to create an annular groove 52 around its outer cylindrical surface midway between its ends, and a corresponding degree of ingress of the material of the tube or ring 50 on the inside thereof into the swirler 26 to form an interference fit therewith. The tube or ring 50 and the swirler 26 have their end faces substantially flush with one another. The thickness of the tube or ring 50 is uniform and is about 3% to 3.5% of the diameter of the swirler 26. The tube or ring 50 is 8.9 mm long and has an outer diameter of 12.1 mm. When one of the illustrated nozzles is in use, gases of the blow torch pass up along the pipe 20 into the lower part 14, and thence through the passageways defined by the slots or recesses of the swirler, and up through the upper part 12 and out through the upper end thereof, where they create a hot flame when lit. The passageways, defined in part by the slots 28 or the recesses 40, impart a swirling to the gases. It will be appreciated that the swirler is held fixed between the shoulders 22 and 24, and cannot rotate or otherwise move relative to the parts 12 and 14 of the nozzle, so the gases are forced to rotate around the axis of the swirler as they flow along the passageways.

[0029] The swirler 26 in all three illustrated embodiments is replaceable by unscrewing the parts 12 and 14, removing the swirler already present, and inserting an unused or cleaned swirler. This is especially desirable if the swirler has become clogged by liquid metal dropping into the nozzle interior.

[0030] Many modifications and variations of the nozzles as shown may occur to the reader without taking the resulting construction outside the scope of the present invention. The diffuser or swirler 26 and the ring 50 are preferably made of brass but other metals or materials can be used.