U.S. patent application number 12/303124 was filed with the patent office on 2009-07-23 for gas burner nozzle.
Invention is credited to Egon Evertz, Ralf Evertz, Stefan Evertz.
Application Number | 20090186310 12/303124 |
Document ID | / |
Family ID | 38529390 |
Filed Date | 2009-07-23 |
United States Patent
Application |
20090186310 |
Kind Code |
A1 |
Evertz; Egon ; et
al. |
July 23, 2009 |
GAS BURNER NOZZLE
Abstract
The invention relates to a gas burner nozzle for flame work,
with a central oxygen supply consisting of several pipes (13) and
with several pipes (11, 12) arranged around the aforementioned
oxygen supply for the supply of fuel gas. According to the
invention, the pipes for the oxygen supply are arranged in groups,
with the individual groups arranged coaxially and at a distance
from each other, and with each group consisting of at least two
rows of pipes arranged in the form of concentric rings.
Inventors: |
Evertz; Egon; (Solingen,
DE) ; Evertz; Ralf; (Leichlingen, DE) ;
Evertz; Stefan; (Solingen, DE) |
Correspondence
Address: |
K.F. ROSS P.C.
5683 RIVERDALE AVENUE, SUITE 203 BOX 900
BRONX
NY
10471-0900
US
|
Family ID: |
38529390 |
Appl. No.: |
12/303124 |
Filed: |
May 18, 2007 |
PCT Filed: |
May 18, 2007 |
PCT NO: |
PCT/DE07/00902 |
371 Date: |
December 2, 2008 |
Current U.S.
Class: |
431/350 |
Current CPC
Class: |
F23D 2900/14642
20130101; F23D 14/58 20130101; F23D 14/56 20130101; F23D 14/22
20130101 |
Class at
Publication: |
431/350 |
International
Class: |
F23D 14/46 20060101
F23D014/46 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 2, 2006 |
DE |
20 2006 008 760.5 |
Claims
1. A gas burner nozzle for flame treatment operations with a
central oxygen feed which comprises a plurality of tubes, and with
a plurality of tubes for the fuel gas feed which are arranged
around the oxygen feed. wherein the tubes for the oxygen feed are
arranged in groups in each case, wherein the individual groups
[[(11, 12, 13)]] are arranged coaxially and a distance apart from
each other, and each group [[(11, 12, 13)]] comprises at least two
annularly arranged rows of tubes.
2. The gas burner nozzle as claimed in claim 1 wherein there are
three groups [[(11, 12, 13)]] of tubes for oxygen feed.
3. The gas burner nozzle as claimed in claim 1 wherein each
individual tube for oxygen feed has an outlet inside diameter of 6
to 12 mm.
4. The gas burner nozzle as claimed in claim 1 wherein each group
of feed lines has a separate gas feed control facility.
5. The gas burner nozzle as claimed in claim 1 wherein individual
tubes of a group are combined to form a sub-group which form in
each case a one-piece body which is arranged in the gas burner
nozzle preferably in an exchangeable manner.
6. The gas burner nozzle as claimed in claim 1 wherein the groups
of tubes are arranged in an end piece which is connected to a front
block which has three pre-chambers [[(16, 17, 18)]] for oxygen feed
which are arranged coaxially to each other and connected in each
case to the tubes of one of the groups [[(11, 12, 13)]].
7. The gas burner nozzle as claimed in claim 1 wherein the gas feed
tubes consist of copper.
8. The gas burner nozzle as claimed in claim 1 wherein the outside
diameter is 250 to 400 mm.
9. The gas burner nozzle as claimed in claim 1 wherein each tube
for oxygen feed is formed as a combination of a Laval nozzle
[[(100)]] with a cylindrical tube [[(101)]].
10. The gas burner nozzle as claimed in claim 9 wherein the length
[[(L.sub.2)]] of the first section [[(121)]] is shorter than the
length [[(L.sub.3)]] of the second section [[(122)]] and/or of the
third section [[(123)]].
11. The gas burner nozzle as claimed in claim 1, wherein the
diameter of the three sections, and also their lengths, are matched
to each other so that the gas flows out at the nozzle discharge end
in pulse form.
12. The gas burner nozzle as claimed in claim 11 wherein the
impulse frequency at the nozzle discharge end is 100 to 650 Hz.
13. The gas burner nozzle as claimed in claim 1 wherein the maximum
gas flow velocity in each tube is Mach 2 [[(equal to twice the
speed of sound)]].
Description
[0001] The invention relates to a gas burner nozzle for flame
treatment operations, with a central oxygen feed which comprises a
plurality of tubes, and with a plurality of tubes for a fuel gas
feed which are arranged around the the oxygen feed.
[0002] Gas burner nozzles are used in flame treatment devices which
are formed either as automatic devices or as hand-held flame
treatment devices. Flame treatment operations are especially
necessary for flame scarfing of slab surfaces. So, during the
cooling of the slabs, which are produced by casting, unwanted
cracks are frequently created on their surface which are removed by
means of a surface treatment. The same also applies to burrs or
whiskers which are created when machining the slabs, for example by
cutting. The flame scarfing burners which are used are guided along
the affected surfaces in order to remove the surface defects.
[0003] In the case of gas burner nozzles of the described type,
there is the risk that during burner operation the flame flashes
back. In order to prevent this, it has already been proposed to
provide a porous element inside the nozzle body a long way behind
the discharge orifice, which porous element is to form a safety
barrier (cf. CH-A-472 632 or FR-A-1 448 292).
[0004] Furthermore, when flame scarfing by means of an oxygen jet
of controllable output and orientation, which is enveloped by a
heating flame, it is proposed in EP 0 043 822 [U.S. Pat. No.
4,373,969] to alter the cross section of the jet with regard to its
shape and surface, independently of its output, during the course
of the flame scarfing. The burner which is designed for this has an
oxygen nozzle which is divided into a plurality of nozzles which
are grouped adjacent to each other and as a compact bundle. This
bundle of nozzles is surrounded by further nozzles which form in
each case a burner for heating, wherein these nozzles and burners
are provided with devices for individual feed with gas or oxygen,
or a heating mixture. Each feed device can be individually
controlled. As is apparent from the illustrated embodiment, 65
concentrically arranged oxygen feed tubes, with an equal distance
to the adjacent tube in each case, are used, and which in turn are
surrounded by 12 tubes with larger diameter in each case for
heating gas feed. As a result of the controlling facility which is
provided, effective burner cross sections are to be created, which
are circular, rectangular or oval.
[0005] Furthermore, gas burners are known which have a plurality of
tubes for an oxygen feed which are arranged coaxially to each other
and which are surrounded by a plurality of tubes for a gas fuel
feed which are arranged around them.
[0006] In the case of gas burners of the described type, according
to the prior art diameters of the burners, which are circular in
cross section, are customarily from 200 to 250 mm. This has the
disadvantage that narrow sides of slabs have to be overtraveled
many times with such burner nozzles. A simple enlargement of the
burner diameter for example to 300 mm is in no way sufficient since
the temperature would then be greatest in the center of the burner
jet or burner jet cone on account of the greater heat and the
melting on the workpiece would be correspondingly more intense than
on the edge which in the case of longitudinally-guided burners
leads to a surface which is concave in cross section. A further
technical problem is the relatively high oxygen consumption.
[0007] It is therefore the object of the present invention to
disclose a gas burner nozzle which with the lowest possible oxygen
consumption and short machining time enables an optimum surface
quality of the workpiece which is to be treated.
[0008] This object is achieved by a gas burner nozzle as claimed in
claim 1.
[0009] According to the invention, the tubes for oxygen feed are
not arranged equidistantly or on rings which are equal distances
away from the center, but arranged in groups, wherein the
individual groups are arranged coaxially and a distance apart from
each other, and each group comprises at least two annularly
arranged rows of tubes. In particular, three groups of tubes for
oxygen feed are provided. In other words, 3 ring sections are
preferably provided, which are a distance apart from each other and
inside which individual tubes are arranged in each case, the
distance from each other of which is less than the distance of the
ring sections from each other. Rows of tubes for oxygen feed, which
are arranged in 2 or 3 rings, can be associated with each group.
Around the the tubes for oxygen feed, a group of nozzle orifices
with smaller diameters in each case is provided on an outer ring,
via which nozzle orifices the fuel gas is fed.
[0010] If a slab long side is overtraveled with such a nozzle,
which has a diameter of 280 to 400 mm, then this can be treated in
a single pass, wherein a slab surface has been created which is
flat as far as possible. As a result of the repeated overtraveling
of this long side being dispensed with, a saving of oxygen is
already made to a significant degree. Surprisingly, an oxygen
saving of about 25% per time unit additionally resulted, which is
only possible by means of the newly created nozzle arrangement.
[0011] Each individual tube for oxygen feed preferably has an
outlet inside diameter of 6 to 12 mm, especially 8 mm. As basically
known according to the prior art, the gas burner has separate
oxygen feed lines which can be separately controlled. In the
present case, each separate gas feed is connected to a group of
feed lines, i.e. to a ring section.
[0012] According to a further development of the invention,
individual tubes of a group, preferably two to three tubes, are
combined to form a sub-group which forms in each case a
single-piece body which is arranged in the gas burner nozzle in an
exchangeable manner. In this way, damaged surface sections on the
end face can be partially renewed by exchange of affected
sub-groups.
[0013] The the groups of tubes, according to a development of the
invention, are arranged in a single end piece to which is connected
a front block which has three pre-chambers for oxygen feed which
are arranged coaxially to each other and connected in each case to
the tubes of a (ring) group. By means of this measure, the gas
burner nozzle weight can be considerably minimized. For service
life reasons, the gas feed tubes are produced from copper.
[0014] The length of any tube is determined by the distance which
is required in order to avoid turbulences at the far end of the
tube which can lead to an explosion-like burn-out with
corresponding nozzle damage. In particular, an optimum design of
the individual tubes (preferably 8 mm wide at the outlet) has been
created if each tube for oxygen feed is formed as a combination of
a Laval nozzle with a cylindrical tube which is oriented toward the
outlet. The Laval nozzle, which is known principally according to
the prior art, has two cone-like sections, wherein the first cone,
as seen in the flow direction, is formed in a converging manner and
the cone which follows it is formed in a diverging manner. A
cylindrical tube with constant diameter as far as the tube outlet
is attached on the end of the diverging section.
[0015] From fluid dynamics it is known that with laminar flows in a
tube, in which a constant pressure is applied, the flow velocity
increases reciprocally to the reduction of diameter. As a result of
the tube design, the gas flow which is guided within it is made to
oscillate, wherein high-frequency impulse sequences are created on
account of the interaction of the flow. The achievable impulse
frequencies and also the amplitudes depend particularly on the
inlet pressure, the degree of convergence, and the degree of
divergence of the tube diameter, and also upon the length of the
third section with a constant diameter. During flame scarfing, the
shock-like impulses which leave the nozzle discharge end lead to
liquid substances, which are created as a result of melting of the
workpiece surface which is to be treated, and also solid particles,
which are perhaps included, being blown away from the surface. This
leads both to an increase of the surface quality of the treated
workpiece, for example a slab surface, and to a further reduction
of the oxygen consumption. Within the scope of the present
invention, the diverging section can follow the first converging
section of the inside cross section directly or by interposition of
a section with constant diameter. As long as a section with
constant diameter is present, the flow velocity in this section is
maintained without superpositions occurring which are desired in
the diverging section and in the extension tube which follows it.
The short section with constant diameter should preferably be
smaller than the respective lengths of the converging and of the
diverging section in any case.
[0016] Further explanations for the present invention and also
advantages are described with reference to the attached drawings.
In the drawings:
[0017] FIG. 1 shows a plan view of a gas burner nozzle,
[0018] FIG. 2 shows a partial cross section through this gas burner
nozzle,
[0019] FIGS. 3a to d show cross sections in each case through a
tube for oxygen feed with different gas flow structures.
[0020] The gas burner nozzle for flame treatment operations which
is shown in FIG. 1 has a central oxygen feed section with a
plurality of tubes which are arranged in groups. In the present
case, the outer ring section 11 is formed by individual tubes,
wherein the tubes 111 are arranged on an outer ring, the tubes 112
are arranged on a ring which follows next, and tubes 113 are
arranged on an inner ring. The tubes 112 and 111 or 113 are
arranged in each case with a "stagger" in an offset manner to each
other. The tube diameter is 8 mm, and the tube distance of the
tubes 111, 112 and 113 from the adjacent tube is about 4 mm in each
case.
[0021] In the center ring section 12, two rows of individual tubes
are arranged on different diameters and are also offset to each
other so that a distance of 4 mm from the respectively next tube is
established.
[0022] In the central ring section, 4 tubes are arranged in the
innermost ring 4, and in the rings which follow it 12 tubes are
arranged in each case. In the present case, this gives a total
number of 148 tubes for oxygen feed. Tubes for fuel gas feed, which
have a significantly smaller diameter, are located all around on
two coaxially arranged rows 14 and 15. The entire nozzle head 10
consists of copper, wherein the gas burner nozzle can be formed as
a solid body in which a corresponding number of holes have been
manufactured.
[0023] In contrast, FIG. 2 shows a variant in which only an outer
front section is solidly constructed, to which a front block is
connected, in which a central oxygen feed 16 to the tubes of the
ring group 13, a gas feed 17 which lies coaxially to this central
oxygen feed and leads to the tubes of the ring group 12, and an
outer coaxial gas feed 18 which leads to the group 11 of tubes, are
arranged. Each of the three gas feeds 16, 17 and 18 can be
separately controlled so that the gas velocity in the individual
tubes can be correspondingly controlled.
[0024] Each individual tube, for example 111, 112, 113, is
preferably formed in such a way that a cylindrical tube 101 with a
length L.sub.K is connected to a Laval nozzle 100 with the length
L.sub.C. This Laval nozzle has a first converging section 121,
which extends over a length L.sub.2, and a diverging section 122,
which has a length L.sub.3. In between these the sections, a
sub-section with a length L.sub.4 can be arranged, which has a
constant minimum diameter d.sub.min. The diameter of the
cylindrical tube 101 is identified by d.sub.k and has the size of
the largest diameter of the cone-shaped divergence 122. The length
L.sub.k or L.sub.5 can be varied, for example between the length
measurements 72 mm, 65 mm and 25 mm. The length L.sub.2 for example
can be selected with 10 mm, the length L.sub.4 with 2 mm, and the
length L.sub.3 with 25 mm. The gas which flows into the tube has a
pressure P.sub.0 of for example 1.3.times.10.sup.6 Pa and a
temperature T.sub.0 (for example room temperature). By variation of
the pressure Po in relation to the outside pressure (environmental
pressure), the jet cone of the discharging oxygen flow can be
varied to form convergent, divergent or essentially parallel
shapes. By means of the inlet pressure P.sub.0, moreover, the
differently resulting oscillation frequencies and oscillation
amplitudes are varied.
* * * * *