Note: Descriptions are shown in the official language in which they were submitted.
'~43~2~
BERLITZ TRANSLATION SERVICES PAGE 6 No. 790181g6
The invention relates to a process and a device for high-speed
flame spraying of refractory wire or powder weld filler for the
coating of surfaces, in which an all-gas high-speed flame spray
burner is used to coat surfaces with any refractory wire or
powder spray weld filler.
In that regard two or more gas mixing systems that operate
independently from each other, which can operate with different
fuel gas-oxygen mixtures, are integrated in the device.
A multiplicity of processes, devices and technologies are known
from prior state of art that no longer meet the high requirements
of modern technology.
DE-PS 81 18 99 proposes an arrangement for atomizing metallic and
non-metallic substances, which can be viewed as the basic
principle for high-speed spraying using fuel gas and oxygen. The
arrangement primarily involves a system comprised of a combustion
chamber and expansion nozzle, with which wire, powder or molten
spray weld fillers can be sprayed using primarily hydrogen as
detonating gas. Therefore, when using the proposed device, only
one heating or fuel gas, primarily hydrogen, ~an be used each
time, which according to the compressed gas principle is
introduced into the combustion chamber. According to DE-PS
81 18 99, the ignition of hydrogen is done manually when emerging
from the expansion nozzle, electrically by short circuit or by
means of an electric arc.
Hydrogen can be ignited by means of the molten heated spray weld
filler, which is combined with the detonating gas through the
combustion chamber via an access.
The design concept proposed in DE-PS 81 18 99 in many respects
does not meet the requirements imposed today on high-speed flame
spray equipment.
On the one hand the fuel gas, which according to DE-PS 81 18 99
is hydrogen, is introduced according to the compressed gas
principle into the combustion chamber, which no longer fulfills
either the legal type approval requirements for autogenous
burners or accident prevention provision UVV-VGB 15.
In addition, hydrogen without additional oxidation gas, such as
oxygen, does not produce sufficient heat to be able to spray
refractory spray weld fillers such as molybdenum, wolfram and
oxides. On the other hand, hydrogen burns reducing and for that
reason is unsuitable for spraying metal oxides, since the
hydrogen flame takes oxygen from the spray weld filler in the
molten or plastic state.
Another high-speed flame spray system is known from EP-o 049 915.
This high-speed flame spray system has a water cooled expansion
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BERLIT~ TRAI~SLATION SERVICES PAGE 7 No. 79018196
nozzle that is supposed to be suitable for spraying wire or
powder weld fillers. In contrast to the concept of
DE-PS 81 18 99, the heating gas used may be optionally nitrogen,
propane or MAPP gas, in addition to oxygen. The individual fuel
gases are introduced according to the compressed gas principle
into a large mixing chamber and mixed with oxygen. The fuel gas-
oxygen mixture moves through bores into the water cooled
expansion jets, where it is combined in the combustion chamber
with the powder or wire weld filler.
This method in accordance with EP-Al-0 049 915 also suffers from
numerous technical applications and safety problems.
The design concept proposed in EP-Al-0 049 915 precludes the use
of acetylene as heating gas, since, because of the high rate of
flame propagation of acetylene, the risk of flame backfire or
backflash, due to the compressed gas principle, is extremely
high.
Excluding the use of acetylene in connection with oxygen
significantly limits applications, since due to the high flame
energy particular weld fillers such as refractory metals and
oxides can be sprayed and melted only with an acetylene-oxygen
flame at 3160C. The extremely high rate of flame propagation of
an acetylene-oxygen mixture, approximately 11.5m/sec., compared
with propane-oxygen, which in a mixture ratio of 1:5 is about
3.6m/sec., which results in practice in significantly higher
rates of flame propagation and therefore higher kinetic particle
speeds, cannot be taken advantage of in the proposed system. Gas
mixing systems of the type described above do not fulfill the
accident prevention requirements of VGB 15 nor the type approval
requirements for autogenous devices.
The acetylene-oxygen flame possesses dominant properties that
cannot be obtained by any other fuel gas-oxygen mixtures. For
that reason it is ideal for thermal spraying of refractory weld
fillers.
However, the use of acetylene as a heating gas to operate high-
speed flame spray systems in connection with oxygen is
problematic due to the specific structure of the acetylene
molecule.
Acetylene is a chemical combination of carbon and hydrogen. It
is a so-called unsaturated hydrocarbon, whose molecule possesses
an inner tension and seeks equilibrium. Therefore, acetylene is
not a stable substance, but instead is inclined to decompose into
its components, i.e. carbon and hydrogen. For example, when
acetylene is heated to a temperature of about 300C, and if it is
also under pressure, then any decomposition initiated will be
continued by the entire gas quantity. The energy released in the
form of heat is sufficient to bring neighboring acetylene
2~302~
particles to decomposition temperature. That process occurs so
rapidly that when decomposition is initiated compressed
acetylene decomposes in an explosive manner. That condition can
occur, for example, if acetylene is introduced into a combustion
chamber of a high-speed burner and is ignited; the expansion
produces a combustion chamber pressure in the order of magnitude
between 2 and 3.5 bar, so that because of the backdraft on the
fuel gas line the aforementioned acetylene decomposition occurs.
Because of the condition described a~ove,
back-ignition in the gas mixture area occurs where fuel gases,
in this case acetylene and oxygen, are combined. The
aforementioned neyative occurrence prevents the fuel gas,
acetylene and oxygen from combustin~ in the combustion chamber
and in that way a high-speed flame can be produced.
Moreover, it is known that in the current state of
the art oxide-free spray coatings, such as those made of
hastelloy, tribaloy or extremely pure nickel can only be
produced using plasma vacuum chamber spraying. That technology
is very complex ad extremely cost intensive.
The present invention therefore makes it possible to
create a process and device that can operate with acetylene and
oxygen without difficulty.
In addition, in accordance with the present teaching
it is possible to simplify the coating process significantly and
to reduce costs and simultaneously improve coating quality in
regard to optimization of the adhesive strength of the weld
2a4~
- 9
filler to the substrate, by achieving a significantly higher
kinetic energy of the flame jet, so that at the same time lower
porosity and thus higher impermeability of the spray layer are
achieved.
In accordance with a first aspect of the invention
there is provided, a process for high-speed flame spraying of
refractory wire and powder weld filler for the coating of
surfaces by means of at least two gas mix systems operating
independently of each other, comprising the steps of bringing
the wire or powder spray weld filter into a primary chamber and
melting it by primary even flames arranged concentrically around
a charging channel, accelerating with the resulting high-spePd
flame and conveying through a primary expansion nozzle bore into
a downstream secondary combustion chamber, the latter being
streamed through while the molten plastic weld filler is carried
along by the primary high-speed flame at supersonic speed
running into an axially centrally widened downstream, water
cooled secondary expansion nozzle or the bore thereof, such that
in the area of the radially, axially and/or focusingly arranged
secondary fuel gas-oxygen channels through a combustion chamber
a partial vacuum area is produced where a hot gas mixture with
low streaming pressures can be supplied, and wherein the
secondary chamber radially, axially around the primary
high-speed flame the heating gas mixture is caused to ignite,
expands and because of high flame temperature and extreme rates
of flame propagation and combustion contributes to the melting
~31~2~
- 9a -
of the remainder of the spray weld filler and to its additional
acceleration.
Preferably the primary gas mixture occurs in the
intermediate piece designed as an injector gas mixing block and
the secondary gas mixture occurs in the primary combustion
chamber housing designed as a mixing block for secondary gases.
A particularly preferred embodiment of the invention provides
for the primary heating gas mixture following directly in a gas
mixing block according to the injector principle in the direct
vicinity of the primary combustion chamber. In a particularly
preferable embodiment of the invention the primary combustion
chamber and/or the expansion nozzle in the secondary injector
gas mixing block is (are) integrated in the secondary injector
gas mixing block. Alternatively, it is possible to add the
spray weld filler, which may be in the form of powder and the
powder transport gas at room temperature or the powder spray
weld fillers and/or the powder transport gases preheated. Here
the connection for the spray weld filler and/or powder transport
gases is equipped with a water cooling system. The cold or
preheated spray weld filler is melted on when being conveyed
through the primary combustion chamber, brought through the
primary heating flame through the secondary combustion chamber,
melted and accelerated and exits through the expansion jet bore
with the secondary flame.
In accordance with a second aspect of the invention
there is provided, a device for high-speed flame spraying of
2~3~2~
- 9b -
refraction wire or powder weld filler for the coating of
surfaces, comprising a base body, operating components-connector
block with distributor chambers, injector gas mixing block,
combustiQn chamber housing and a central bore for spray weld
S fillers and cooling equipment, wherein beginning from the
operating components-connector block the secondary gas,
secondary heating gas, primary gas and primary heating gas
channels are respectively led separately to a primary combustion
chamber or a secondary combustion chamber, whereby the spray
weld filler channel or charging channel surrounded by the
primary gas/heating has channels leads out into the primary
combustion chamber and the secondary gas/heating gas channels
through the primary combustion chamber in the direction of the
expansion nozzle run into the secondary combustion chamber~
A preferred embodiment of the invention is
characterized in that the device is comprised of an
operating components-connector block, a device base body,
a gas mixing block support, an injector gas mixing block,
a primary combustion chamber housing with internal
part or central bore body, press-in screw and hasp
2~43024
BERLITZ TRANSLATION SERVICES PAGE 10 No. 7901~19
part, as well as secondary expansion nozzle body, internal screw
sleeve and external screw sleeve.
It is preferably foreseen that the operating components-connector
block has at least one each cooling water connector, a secondary
gas connector, a primary gas conneetor, a connector for powder
weld fillers and for wire spray fillers, a primary heating gas
eonneetor, a seeondary heating gas conneetor and a cooling water
baekflow eonneetor, whieh continue as channels up to the face
surfaee of the operating components-eonneetor bloek or the
distributor ehambers arranged there.
These ehannels or the distributor ehambers of the operating
eomponents-eonneetor bloek eorrespond with same-medium channels
of the deviee base body, whieh is eonneeted on the operating
eomponent-eonneetion bloek.
The deviee base body receives at least partially a gas mixing
bloek support for seeondary gases, and an injeetor gas mixing
bloek for primary gases is arranged in the gas mixing block
support.
Another partieularly preferable embodiment of the invention
eonsists of the deviee base body having ehannels that correspond
with the ehannels or with the ring ehannels arranged on the face
surfaee of the operating eomponents-eonneetor bloek.
An additional embodiment eonsists of having the ehannel of the
deviee base body running in a eooling water advanee ehannel
between the internal serew sleeve and the external screw sleeve,
while the eooling water baekflow ehannel eorresponds with the
eooling water baekflow channel formed between the device base
body and the press-in screw.
The gas mixing block support is preferably interspersed with at
least one eaeh seeondary gas and seeondary heating gas channel,
in whieh eaeh eorresponds on one side with the same-medium
ehannels of the deviee base body and on the side facing the
primary combustion ehamber runs into radial grooves arranged
there for seeondary heating gas and seeondary gas.
The injeetor gas mixing bloek for primary gases has at least one
eaeh primary heating gas channel and one primary gas channel as
well as a eentral bore for spray weld fillers, whereby these
ehannels correspond on one side with the same-medium channels of
the deviee base body, and the primary gas channel runs into a
radial annulus between the gas mixing bloek support and the
injector gas mixing block or the channel for primary heating gas
runs into an annulus for oxygen distribution, while the central
bore leads up to the face side of the injector gas mixing block
and starting from the annulus for oxygen distribution, injector
2 f~
8ERLITZ TRANSLATION SERVICES PAGE 11 No 7901819
nozzle bores are conducted to the injector gap, from which
injector mixing nozzle bores continue to a radial groove.
It is preferably contemplated that the injector gas mixing block
in the direction of the expansion jet is connected to a primary
combustion chamber housing, which receives an internal part with
injector gas mixing bores as well as a bore for the spray
fillers.
In that regard the injector gas mixing bores are arranged
focusing and/or axially in the internal part.
On the face side of the internal part facing the injector gas
mixing block a radial ring groove for fuel gas, oxygen-primary
gas is arranged, which corresponds with the radial ring groove of
the injector gas mixing blocX, as does the centrally arranged
bore for spray weld fillers of the internal part with the central
bore of the injector gas mixing block
It is preferably envisioned that the primary combustion chamber
housing on the face side facing the gas mixing block support has
one each radial ring groove for secondary heating gas and one
radial ring groove for secondary heating oxygen, which correspond
with the same-medium radial grooves of the mixing block support.
The individual corresponding channels continue from these radial
ring grooves, and the latter converge in a radial ring groove
(injector gap), since the channels lead directly to or through
injector pressure nozzle bores into the radial ring groove.
In that regard it is envisioned that these channels are formed at
least partially by the gap between the primary combustion chamber
housing and the hasp part.
Commencing from the radial ring groove, axial and focusing bores
lead to the secondary combustion chamber.
These bores lead away through the primary combustion chamber.
The expansion jets are contiguous to the secondary combustion
chamber.
The cooling water channel proceeds, commencing at the connection
of the operating components-connector block, through the device
base body, between the internal screw sleeve and the external
screw sleeve, to the radial bore on the expansion jet outlet bore
and then over into the cooling water backflow, since the cooling
water channel extends between the expansion nozzle body and the
internal screw sleeve and merges into a cooling water annulus,
and from there a cooling water channel leads to the cooling water
backflow connector of the operating components-connector block.
2~4~024
- 12 -
Additional particularly advantageous embodiments of
the invention are characterized in that the primary combustion
chamber housing is designed as secondary gas mixing block. The
primary combustion chamber of the combustion chamber housing has
a transitional expansion nozzle bore.
Embodiments of the invention will now be described
with reference to the accompanying drawings wherein:
Figure 1 shows a cross-section of the device
embodying the invention;
Figure 2 shows an enlargement of Figure 1
illustrating the primary system;
Figure 3 shows an enlargement of Figure 1
illustrating the secondary system;
Figure ~ shows the operating components-connector
block 9;
Figure 5 shows the device base body 12;
Figure 6 shows the gas mixing block support 14;
Figure 7 shows the injector gas mixing block 13;
Figure 8 shows the primary combustion chamber housing
29;
Figure 9 shows a cross-section along line A-A as
shown in Figure l;
Figure 10 shows a cross-section along line B-B as
shown in Figure l;
Figures 11 - 13 are diagrams of the properties of
acetylene oxygen flames;
~3~
- 12a-
Figure 14 shows a variation of an embodiment in which
the primary heating gas mixture occurs directly in a gas mixing
block according to the injector principle in the direct vicinity
of the primary combustion chamber.
Figure 1 shows a device embodying the invention for
high-speed flame spraying, which is designed as a flame spray
gun.
The device is comprised of an operating
components-connector block 9, a device base body 12, an
internal mixing nozzle block/injector gas mixing block
for primary gases 13 and gas mixing block support 14,
a primary combustion chamber housing 29 with hasp part
80 and press-in screw 62, expansion nozzle body 39 and an
internal screw sleeve 34 and external screw sleeve 35
~3~ ~
BERLITZ TRANSLATION SERVICES PAGE 13 No. 79018196
surrounding it as well as an internal part 76 receiving the
central bore body ~1.
The device is interspersed with a cooling water advance
channel 1, a secondary gas channel 2, a primary gas channel 3, a
central bore for weld fillers (in the form of powder or wire) 4,
a primary heating gas channel 5, a secondary heating gas
channel 6 and a cooling water backflow channel 7. The primary
gas and the primary heating gas are mixed in the injector gas
mixing block for primary gases 13 and enter into the primary
combustion chamber 28, whereby the wire or powder spray weld
filler also introduced into primary combustion chamber 28 is
melted by primary heating flames 64 arranged concentrically
around charging channel 4, with the resulting high-speed flame 65
accelerated and conducted through a primary expansion nozzle
bore 30 into a downstream secondary combustion chamber 32. The
latter is streamed through while the molten plastic weld filler
is carried along by primary hig~-speed flame 65 at supersonic
speed, which runs into an axially centrally widened, downstream
and water cooled secondary expansion nozzle 39 or into its bore
38, so that in the area of secondary fuel gas-oxygen combustion
channels 44, 45,.which are arranged in a radial, axial and/or
focusing manner and run into secondary combustion chamber 32, a
partial vacuum zone is produced and a hot gas mixture with low
streaming pressures can.be supplied, whereby in secondary chamber
32 radially, axially around the primary high-speed flame 65 the
hot gas mixture ignites, expands and because of a high flame
temperature and an extreme rate of flame propagation and
combustion contributes to melting the remainder of the spray weld
filler and to its additional acceleration.
External screw sleeve 35 here surrounds internal screw sleeve 34
in such a way that an annulus .~6 is formed for the cooling water
advance. Internal screw sleeve 3~ has an internal threading 83,
and can therefore be screwed onto external threading 84 of device
base body 12 and sealed by means of O-ring 19. External screw
sleeve 35 has external threading 85, which engages in an internal
threading 86 of device base body 12 and is therefore screwed into
the latter. Here, too, an O-ring 15 is included for sealing
purposes. By means of this arrangement annulus 36, which is
generally designated with reference number 1, of the cooling
water advance is continued up to device base body 12. In the
region of expansion nozzle outlet bore 43 O-ring seals 41 and 42
are also arranged between external screw sleeve 35 and in~ernal
screw sleeve 34 as well as between internal screw sleeve 34 and
expansion nozzle body 39.
Commencing at annulus 36 a cooling water channel lc leads through
device base body 12 up to cooling water channel lb of the
operating component-connector block 9, which has a connection for
cooling water access la.
~3~2~
BERLITZ TRANSLATION SEF~VICES PAGE 14 No. 7901819f)
Operating component-connector block g is secured hy means of
countersunk screws 8 on device base body 12 and sealed by means
of O-rings 50, which each surround and seal connecting channels
la through 7a as well as screws 8.
Inside of internal screw sleeve 34 is located expansion nozzle
body 39, which is screwed onto the internally located primary
combustion chamber housing 29.
Here in turn an annulus 37 is formed for cooling water backflow
between expansion nozzle body 39 and internal screw sleeve 34.
The latter in turn merges into a larger annulus 33, in which
cooling water channel 7d commencing from device base body 12 and
operating components-connector block 9, runs here into
channel 7a.
Here cooling channel 7d continues through the gap between device
base body 12 and press-in screw 62 up to annulus 33.
In that fashion the cooling system proceeds in the following way:
Beginning from cooling water connector support 1 of the operating
components-block 9, cooling water flows through the cooling water
inlet channel la into cooling water advance channel lb of the
device base body via annulus 36, divided between external screw
sleeve 35 and internal screw sleeve 34 to the radial bores for
cooling water 40 (cooling water advance) on expansion nozzle 39.
The cooling water flows through annulus 37 between expansion
nozzle 39 and internal screw sleeve 34 through cooling water
channel 7d back to connector support 7 for cooling water
backflow.
Based on Figs. 2 and 3, as well as details 4 through 8, the two
independently operating gas mixing systems in this embodiment of
this invention will be described in greater detail. The
description relates to the device as shown in Fig. 1.
In Figs. 2 and 3 the cooling water advance is indicated with
broken lines and cooling water backflow is indicated with dash-
dot lines. The secondary gas path is shown by wavy lines running
diagonally from the upper left to the lower right and the
secondary heating gas path is shown with wavy lines running
diagonally from the lower left to the upper right. The primary
gas path was illustrated with horizontal wavy lines and the
primary heating gas movement was shown with vertical wavy lines,
with the intersecting wavy lines indicating the mixture. In the
central bore the spray weld filler is indicated with dots.
In regard to Fig. 2, reference is first made to the primary
system. Here operating components-connector block 9 has for
example, inter alia a connector 3a for heating oxygen (primary
gas) and a connector 5a for fuel gas H2, propane, etc. (primary
heating gas).
BERLITZ TRANSLATION SERVICES PAGE 15 No. 79018196
From connector 3a for heating oxygen (primary gas) a canal 3b
runs through operating components-connector block 9 into an
oxygen distributor chamber 11, on face side 68 of the operating
components-connector block 9 facing device connector block 12.
Primary heating oxygen channel 3 is formed by individual channels
3c in device base body 12 and channel 3d and in injector gas
mixing block 13. In that regard channel 3c runs into oxygen
distributor chamber 11 and channel 3d runs into annulus 56 for
oxygen distribution in the internal mixing nozzle block or
injector gas mixing block 13. From connector 5a for fuel gas, a
channel 5a leads within operating components-connector block 9
into a fuel gas distributor chamber 10, which is also arranged on
face surface 68 of operating components-connector block 9. From
there channel 5c in device base body 12 leads to channel 5d,
which runs into annulus 57.
Oxygen distribution occurs in annulus 56, and it functions as a
pressure equalization chamber. Through injector pressure nozzle
bores 58 the oxygen streams through the ring groove (injector
gap) 57a connected to annulus 57, and thereupon streams through
the various injector mixing nozzle bores 59, with the fuel gas
out of the injector gap tannulus 57a) being carried along. The
fuel gas-oxygen mixture moves through radial ring groove 22/22a
through fuel gas-oxygen mixture bores 47 and 48 into primary gas
combustion chamber 28. Fuel gas (primarily hydrogen, propane gas
or propylene) is added at connector 5 and moves through fuel gas
distributor chamber (pressure equalization chamber) 10 through
connector bores 5c/5d into radial annulus 57 into radial ring
groove 57a, injector gap, from which the fuel gas, due to the
injector effect of the oxygen streaming through at supersonic
speed, is carried along into injector mixing bores 59 and mixed.
The fuel gas-oxygen-primary mixture moves through bores 47 and 48
into primary combustion chamber 28.
The injector effect in the internal gas mixing block is obtained
due to the higher streaming pressure of oxygen compared with the
fuel gas streaming pressure. If the primary fuel gas-oxygen
mixture coming from expansion nozzle bore 43 (see Fig. 1) is
ignited, the flame flashes back into primary combustion chamber
28. From cylindrical combustion chamber bore 30 or 46 the fuel
gas-oxygen mixture now burns out as primary high-speed flame
through secondary combustion chamber 32 into water cooled
expansion nozzle bore 38. In the junction area of secondary gas
mixing bores 44, 45, which are arranged concentrically, axially
and focusingly around primary combustion chamber bore 46 a
partial vacuum zone is produced due to the high rate of
combustion of the primary heating gas flow.
The secondary system will now be described in greater detail in
reference to Fig. 3. At connector 2a secondary heating oxygen is
supplied and moves through channels 2b, 2c, 2d into radiai ring
71 ~
BERLITZTRANSLATION SERVICES PAGE 16 No 7901~3196
groove 63/21 (pressure equalization and distributor ring groove).
The oxyqen moves through the oxygen connector bores into a
multiplicity of injector pressure gas bores 24, in which it is
accelerated to supersonic speed and streams through ring
groove 25 (injector gap), carries along fuel gas from ring
groove 25 and runs into the opposing axially and/or focusingly
aligned mixing bores 26 and emerges as a fuel gas-oxygen mixture
from mixing bores 44 and 45. The outflow is positively affected
by the partial vacuum zone in the inlet area produced by the
primary high-speed flame. The fuel gas-oxygen mixture (primarily
acetylene-oxygen mixture) flowing into combustion chamber
(secondary) 32 ignites at the primary high-speed flame and
optimizes the melting process of the spray particles and
increases the rate of combustion and spray particle speed.
In that regard, operating components-connector block 9 has
connector 2a for heating oxygen (secondary gas) and connector 6a
for fuel gas C2, H2 (secondary gas), from whence channels 2b and
6b lead through operating components-connector block 9 on the
face side (68).
From there, within device base body 12, from channel 2b a channel
2c leads to channel 2d of gas mixing block support 14 and a
channel 6c leads from channel 6a to channel 6d of gas mixing
block support 14. Channel 2d leads in turn into a radial ring
groove 63 or 21 and channel 6d leads into radial groove 18. Here
same-medium radial grooves of gas mixing block support 14
correspond with the radial grooves of primary combustion chamber
housing 29, as is also the case in the primary system. Heating
oxygen (secondary gas) streams through bores 23 of the secondary
heating substance through injector pressure nozzle bores 24, half
of which are in focusing position and half in axial position,
into radial ring groove 25 (injector gap), from whence the
mixture continues through bores 44 and 45, as described.
Figs. 2 and 3 also show central bore 4 for powder weld filler or
wire spray filler.
For supply purposes a connector 4 is arranged on operating
components-connector block 9, from which connector channel 4b
continues to face side 68, where it leads into a channel 4c of
device base body 12 or corresponds with the latter. Channel 4d,
which corresponds with bore 49 of the central bore body ~6, then
continues in injector gas mixing block 13.
Fig. 9 shows a section along line A-A in Fig. 1 and Fig. 10 shows
a section along line B-B in Fig. 1.
In Fig. 9 can be seen the junction area of the primary gas
streams into the primary combustion chamber, while Fig. 10 shows
a top view of the junction area of the secondary gas flows.
2~3~
- 17 -
Fig. 9 thus shows outlet bores 44 for the secondary heating
gas-oxygen mixture (axial) and outlet bores 45 for the secondary
heating gas-oxygen mixture (focusing).
In addition, reference number 47 shows the location
of the injector gas mixing bores for the primary heating
gas-oxygen mixture (axial) and reference number 48 shows such
bores (focusing). Reference number 49 indicates the outlet
bores for spray fillers and reference number 81 the central bore
body.
In Fig. 10 the secondary combustion chamber housing
is referenced by number 31, and the primary expansion nozzle
bore by number 30, while reference number 44 indicates the
outlet bores for the secondary heating gas-oxygen mixture
(axial) and number 45 indicates those outlet bores (focusing).
The primary flame outlet-expansion nozzle bore is
labelled with number 46 and the outlet bore for spray fillers is
referenced by number 49.
Fig. 4 illustrates operating components-connector
block 9. It has cooling water advance connector la, secondary
gas connector 2a, primary gas connector 3a, charging channel
connector 4a, primary heating gas connector 5a, secondary
heating gas connector 6a and cooling water backflow connector
7a. They continue with corresponding numbers lb through 7b in
operating components-connector block 9, and channels lb through
7b corresponding with same-medium parts lc through 7c of device
base body 12.
2~ J$~
- 17a -
Only primary gas channel 3b and primary heating gas
channel 5b lead initially into an oxygen distributor chamber 11
or fuel gas distribution chamber 10, and the latter then
corresponds with same-medium channels 3c or 5c. By means of
screws 8 operating components-connector block 9 is connected to
device base body 12 and sealed by O-rings 50 at its frontal
surface 68.
Fig. 5 shows device base body 12. As previously
described, the latter has channels lc through 7c, which
correspond with same-medium channels lb through 7b of operating
components-connector block 9.
Secondary gas c~annel 2c and secondary heating gas
channel 6c of device base body 12 lead into same-medium channels
2d and 6d of gas mixing block support 14, while the primary gas
3c and primary heating gas channels 5c lead into same-medium
channels 3d, 5d injector gas mixing block 13. The central
charging channel 4c corresponds here with channel ~d of injector
gas mixing block 13. Cooling water advance channel lc is
connected at the same time with channel ld, which is formed
2~ between internal screw sleeve 34 and outer screw sleeve 35,
whereby external screw sleeve 35 is screwed onto internal
threading 86 and inner screw sleeve 34 is screwed onto external
threading 84 of device base body 12, whereby they have
corresponding threads 83 or 85.
~43~2~
BERLITZ TRANSLATION SERVtCES PAGE 18 No. 79018196
Cooling water backflow channel 7c is connected with channel 7d,
which is formed between device base body 12 and press-in
screw 62.
Fig. 6 shows gas mixing block support 14. It receives centrally
injector gas mixing block 13 and has secondary gas channel 2d and
secondary heating gas channel 6d described above, which
correspond with channels 2c or 6c of device base body 12.
On frontal side 71 of gas mixing block 14 are located radial ring
grooves 18 for secondary heating gas and 60 for secondary gas,
whereby channel 2d runs into radial ring groove 60 and channel 6d
runs into radial ring groove 18. They in turn are connected with
corresponding same-medium radial ring grooves 20 and 21 of
primary combustion chamber housing 29.
Fig. 7 shows injector gas mixing block 13 received from gas
mixing block support 14, with its channels 3d, 4d and 5d, which
as described above are connected to channels 3c, 4c and 5d of
device base body 12. Channel 3d for primary gas leads into an
annulus for oxygen distribution, and from there through injector
pressure nozzle bores 58 into injector gap 57a, while channel 5d
leads into radial annulus 57 for primary heating gas (fuel gas)
and from there into injector gap 57a. The mixture then continues
through injector mixing nozzle bores 59 into radial ring groove
22a, while central channel 4d for spray weld filler leads up to
frontal side 65 and then merges into central channel 49 of
central bore body 81.
Fig. 8 shows primary combustion chamber housing 29 with its
radial ring grooves 20 for secondary heating gas and 21 for
secondary heating oxygen, as well as received internal part 76
with central bore body 81. This illustration clearly shows that
primary combustion chamber housing 29 also completes the
secondary gas or heating gas mixture. This occurs because the
gas mixture fed out of injector gas mixing block 13 flows through
bores 47, 48 into primary combustion chamber 28 and the s~condary
gas/heating gas components from the gas mixing block support are
conveyed separately into primary combustion chamber housing 29
and merge together there in radial ring groove 25 (injector gap)
and are carried out through primary combustion chamber 28 through
bores 44, 45 into secondary combustion chamber 32 of secondary
expansion nozzle body 39.
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BERLITZ TRANSLATION SERVICES PAGE 19 No. 79018196
The dominant properties of the acetylene-oxygen flame will now be
illustrated in reference to Figs. 11 through 13. Fig. 11 is a
diagram of the flame temperatures of fuel gas-oxygen mixtures,
Fig. 12 shows the rate of flame propagation of fuel gas-oxygen
mixtures and Fig. 13 indicates the primary flame yield of fuel
gas-oxygen mixtures. They show that the acetylene-oxygen flame
possesses dominant properties that cannot be achieved with any
other fuel gas-oxygen mixture. For that reason it is ideal for
thermal spraying of refractory weld fillers.
For the sake of clarity Fig. 11 compares the curve for acetylene
with a mixture according to TRG 103 of
21.5 to 22.5~ acetylene,
71.5 to 73.5% ethylene and
5.0 to 6.0% propylene,
with a mixture of methyl-acetylene and with methane, propylene
and propane.
The same comparisons are made in the diagrams shown in Figs. 12
and 13.
The powder-powder transport gas supply in accordance with Figs. 1
through 8 must also be explained in greater detail.
In normal cases powder and powder transport gas are supplied at
room temperature at connector 4. For special applications,
particularly when spraying refractory metallic or oxide ceramic
powder spray weld fillers, preheated powder transport gases, such
as argon, nitrogen and other gases and preheated powder can be
supplied. If this possibility is usually used, then in contrast
to the illustration in Figs. 1 through 8 connector 4a can be
provided with a water cooling system (cooling water advance and
backflow). The cold or preheated powder-powder transport gas
mixture is conveyed through central bore 4 and runs into primary
combustion chamber 28 out of nozzle inlet bore 49.
The non-prewarmed powder transport gas mixture is melted on by
the high-speed flame and conveyed with the kinetic energy through
the secondary combustion chamber, remelted by the surrounding
secondary heating flame (acetylene + oxygen flame) and
additionally accelerated through water cooled expansion nozzle
bore 38 emerging on the face side from expansion nozzle bore 43
optimally melted or in the molten plastic state with the
secondary high-speed flame at several times the speed of sound.
In the case where preheated flame spray powder and preheated
powder transport gases are supplied to the burner at connector 4
(the preheating temperatures may be between 50 and 800C), the
preheated spray weld filler is previously well melted on, when
the particle is conveyed through the primary combustion chamber
2 ~ 4 '~
BERLITZ TRANSLATION SERVICES PAGE 20 No. 7901819
and arrives from the primary heating flame through the secondary
combustion chamber, where it is again melted, additionally
accelerated, and emerges from the expansion nozzle bore at the
highest possible speed with the secondary fla~e. The preheating
of powdered weld filler and powder transport gas to 50C to 800C
before being added to the burner has several advantages over
adding it cold. For example, the low temperature difference
between the powder particles and the heat yield of the primary
flame should be mentioned; it causes the powder to melt more
satisfactorily after the same dwell time than it would if added
cold. For example, an additional advantage is that the preheated
powder transport gas cools the primary and secondary flame l~ss
than powder transport gas added while cold; that leads to higher
flame heat yield and higher flame propagation rates.
Spray weld fillers can also be supplied through connector 4a
through central bore 4 into the primary comhustion chamber and
melted.
The wire advance is regulated as a function of the melting point
and the wire diameter in such a fashion that a continuous spray
process can occur.
Fig. 14 illustrates an additional variation of an embodiment of
the invention. In this embodiment there is a significant
functional difference in that, in contrast to the embodiment in
accordance with Fig. 1, in which the primary gas mixture occurs
in injector gas mixing block 13, i.e. in an intermediate piece,
here the primary heating gas mixture ~fuel gas and oxygen) occurs
directly in a gas mixing block 13a according to the injector
principle in the direct vicinity of primary combustion
chamber 28, i.e., without an intermediate piece. The
descriptions provided concerning the embodiment shown in Fig. 1
concerning the other elements of the device and process refer to
Fig. 14, while taking into account the adaptation of the
variation of that embodiment, so that the function need not be
described in additional detail, since variation of the
embodiment 14 is considered to be subordinate to the general
spirit of the invention.
Herein described therefore has been a process and a device in the form
of an all-gas high-speed flame spray burner for coating surfaces
with any refractory wire or powdered spray weld filler, which for
example makes it possible to operate without difficulty using
acetylene and oxygen.
2~3~2~
BERLITZ TRANSLATION SERVICES PAG E 2 1 No. ~90181'jf,
Fig. 11
FLAME TEMPERATURES OF FUEL. GAS/OXYGEN MIXTURES
Acetylene
Mixture I*
Mixture with methylacetylene
Propylene
Propane
Methane
Flame Temperature [C]
Fuel Gas Quantity/Oxygen quantity m3/m3
*Mixture I according to TRG 103
11
21.5 - 22.5% acetylene
71.5 - 73.5% ethylene
5.0 - 6.0~ propylene
~302rl
BERLITZ TRANSLATION SERVICES PAGE 22 No. 79018196
Fig. 12
Primary Flame Yield of Fuel Gas/Oxygen Mixtures
Acetylene
Mixture I*
Methane
Mixture with methylacetylene
Propylene
Propane
Primary flame yield [kJ/cm2 s]
Fuel Gas Quantity/Oxygen quantity m3/m3
*Mixture I according to TRG 103
11
21.S - 22.5~ acetylene
71.5 - 73.5% ethylene
5.0 - 6.0% propylene
~ ~ ~ 3 fS ~,
BERLITZ TRANSLATION SERVICES PAGE 23 No. 7901819~5
Fig. 13
Rate of Flame Propagation of Fuel Gas/Oxygen Mixtures
Rate of Flame Propagation [m/s]
Acetylene
Mixture I*
Mixture with methylacetylene
Propylene
Propane
Methane
Combustion Gas Quantity/Oxygen quantity m3/m3
*Mixture I according to TRG 103
21.5 - 22.5~ acetylene
71.5 - 73.5% ethylene
5.0 - 6.0% propylene
