CA2177250A1 - Surface treatment nozzle and method and device for surface treatment using such a nozzle - Google Patents
Surface treatment nozzle and method and device for surface treatment using such a nozzleInfo
- Publication number
- CA2177250A1 CA2177250A1 CA002177250A CA2177250A CA2177250A1 CA 2177250 A1 CA2177250 A1 CA 2177250A1 CA 002177250 A CA002177250 A CA 002177250A CA 2177250 A CA2177250 A CA 2177250A CA 2177250 A1 CA2177250 A1 CA 2177250A1
- Authority
- CA
- Canada
- Prior art keywords
- section
- nozzle
- cross
- surface treatment
- outlet slot
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
- 238000004381 surface treatment Methods 0.000 title claims abstract description 38
- 238000000034 method Methods 0.000 title claims description 13
- 239000002245 particle Substances 0.000 claims abstract description 52
- 239000007787 solid Substances 0.000 claims abstract description 36
- 238000011144 upstream manufacturing Methods 0.000 claims abstract description 6
- 239000000463 material Substances 0.000 claims description 6
- 229920002472 Starch Polymers 0.000 claims description 4
- 230000000750 progressive effect Effects 0.000 claims description 3
- 235000019698 starch Nutrition 0.000 claims description 3
- 239000008107 starch Substances 0.000 claims description 3
- 239000000203 mixture Substances 0.000 claims description 2
- 239000003973 paint Substances 0.000 description 5
- 239000002131 composite material Substances 0.000 description 3
- 238000000926 separation method Methods 0.000 description 2
- 238000005119 centrifugation Methods 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 230000002542 deteriorative effect Effects 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 239000007769 metal material Substances 0.000 description 1
- 239000013528 metallic particle Substances 0.000 description 1
- 238000000465 moulding Methods 0.000 description 1
- 230000010355 oscillation Effects 0.000 description 1
- 230000002250 progressing effect Effects 0.000 description 1
- 238000007873 sieving Methods 0.000 description 1
- 239000011343 solid material Substances 0.000 description 1
- 229940100445 wheat starch Drugs 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B24—GRINDING; POLISHING
- B24C—ABRASIVE OR RELATED BLASTING WITH PARTICULATE MATERIAL
- B24C5/00—Devices or accessories for generating abrasive blasts
- B24C5/02—Blast guns, e.g. for generating high velocity abrasive fluid jets for cutting materials
- B24C5/04—Nozzles therefor
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05B—SPRAYING APPARATUS; ATOMISING APPARATUS; NOZZLES
- B05B1/00—Nozzles, spray heads or other outlets, with or without auxiliary devices such as valves, heating means
- B05B1/02—Nozzles, spray heads or other outlets, with or without auxiliary devices such as valves, heating means designed to produce a jet, spray, or other discharge of particular shape or nature, e.g. in single drops, or having an outlet of particular shape
- B05B1/04—Nozzles, spray heads or other outlets, with or without auxiliary devices such as valves, heating means designed to produce a jet, spray, or other discharge of particular shape or nature, e.g. in single drops, or having an outlet of particular shape in flat form, e.g. fan-like, sheet-like
- B05B1/042—Outlets having two planes of symmetry perpendicular to each other, one of them defining the plane of the jet
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05B—SPRAYING APPARATUS; ATOMISING APPARATUS; NOZZLES
- B05B7/00—Spraying apparatus for discharge of liquids or other fluent materials from two or more sources, e.g. of liquid and air, of powder and gas
- B05B7/14—Spraying apparatus for discharge of liquids or other fluent materials from two or more sources, e.g. of liquid and air, of powder and gas designed for spraying particulate materials
- B05B7/1481—Spray pistols or apparatus for discharging particulate material
- B05B7/1486—Spray pistols or apparatus for discharging particulate material for spraying particulate material in dry state
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Nozzles (AREA)
- Coating With Molten Metal (AREA)
Abstract
Surface treatment nozzle for projecting solid particles carried along in a pressurized gas stream. Said nozzle comprises a channel having, in the direction of flow of the solid particles, firstly a converging section (6), then a diverging section (7) which opens from the nozzle as an outlet slot (4) and whose cross section is flattened parallel to said outlet slot, at least in the vicinity thereof. The channel cross section varies gradually along its entire length; the converging section (6) comprises an upstream end (5) flattened parallel to the outlet slot, the diverging section having two lateral portions of enlarged cross section (41).
Description
~17725Q
SURFACE TREATMENT NOZZLE AND METHOD AND DEVICE FOR
SURFACE TREATMENT USING SUCH A NOZZLE.
The present invention concerns a surface treatment nozzle, as well as a method and a device for surface treatment utilizing such a nozzle, for example for stripping one or more layers of paint or another coating provided on a surface, such as the outside surface of a plane.
In particular, the present invention relates to a surface treatment nozzle intended for projecting solid particles carried in a gas stream under pressure, this nozzle being provided with a single inlet for receiving the solid particles mixed to the gas stream under pressure and a single outlet to project the solid particles, the outlet having the shape of an elongated slot which has a longitudinal axis and extend along this longitudinal axis between two ends, the nozzle including a channel having, in the direction of flow of the solid particles, first a converging section which communicates with the inlet of the nozzle, then a divergent section which opens outside the nozzle through the outlet slot and which has along its entire length a section of a shape which is flattened parallel to said outlet slot, the diverging section additionally having two lateral edges which extend along said diverging section each up to an end of the outlet slot.
A nozzle of this type is disclosed in the document GB-A-2 191 127.
This known nozzle however has the disadvantage that the efficiency of the surface treatment is not equally distributed along the entire width of the nozzle, this efficiency being high at the 21772S~
center of the nozzle and low along the sides of the nozzle jet.
Thus, during stripping operations for example, when such a surface treatment nozzle is moved above a surface which is covered with paint while projecting solid particles, it leaves behind it a stripped mark in the form of a band whose median line has undergone a high stripping, due to the fact that it has been exposed for a long time to the stripping operation and that it has received the solid particles with higher energy, and whose sides are little or badly stripped, due to the fact that they have been exposed for a short time to the projected solid particles and that they have received solid particles projected with lower energy.
This disadvantage requires:
- either to move the surface treatment nozzle at a speed which is sufficiently low for the sides of the stripped mark to be suitably stripped, which slows down the stripping process and may additionally damage the surface which carries paint at the center of the stripped mark, if this surface is sensitive to attacks, for example if this surface is made of a composite material or an undercoat which is deposited on a solid material, - either to redo the edges of the marks already stripped, to suitably strip these edges, which also slows down the stripping process.
Moreover, the nozzle disclosed in the document mentioned above presents a section discontinuity which may result in a rapid wear of the nozzle and which produces turbulences which also disturb the efficiency of the stripping operation, such as when the nozzle is used at important gas ~1 7725~
speeds, and in particular supersonic speeds in the diverging section.
The present invention aims for example to overcome these disadvantages.
For this purpose, according to the invention, a surface treatment nozzle of the type mentioned above is essentially characterized in that the channel has progressing variations of cross-section along its entire length, in that the converging section has a downstream end which has a cross-section which is flattened parallel to the outlet slot, and in that the diverging section has, at least towards the outlet slot, two lateral parts of widened cross-section respectively in the vicinity of the two lateral edges, these two lateral parts of widened cross-section being separated by at least one part of narrower cross-section.
Thus, when the surface treatment nozzle according to the invention is moved above a surface, for example perpendicularly to its outlet slot, by projecting solid particles on this surface, this nozzle leaves behind it a treated mark in which all the points have received particles which have substantially the same kinetic energy and have been exposed to said particles during a substantially identical period. Consequently, the surface treatment is of the same quality along the entire width of the treated mark.
With the surface treatment nozzle according to the invention, it is for example possible to strip a layer of paint which covers an underlying surface made of an undercoating, a composite material or another material without in no way deteriorating said underlying surface.
According to advantageous embodiments, either or all the following provisions may be additionally used:
- the converging section has an upstream end which has a circular cross-section;
- the diverging section includes, substantially along its entire length, said two lateral parts of widened cross-section;
- the diverging section has, at least in the vicinity of its outlet slot, a central part of widened cross-section which is separated from each lateral part of widened cross-section by a part of narrower cross-section, so as to further optimize the equalization of the kinetic energy of the particles which are projected by the nozzle along the entire width of the outlet slot, It is also an object of the present invention to provide a device for a surface treatment including a nozzle as defined above and feeding means to send at the inlet of the nozzle the solid particles mixed with the gas stream under pressure, with a sufficient flow rate to enable the gas stream to be supersonic in the diverging section.
It is also an object of the present 25 invention to provide a surface treatment device including a nozzle such as defined above and positioning means for moving the nozzle essentially in translation along a treatment surface, It is also an object of the present invention to provide a process of surface treatment by projection of solid particles carried in a gas stream under pressure, in which:
. the particles are projected by means of a nozzle such as defined above, . the nozzle is supplied with the mixture of solid particles in the gas stream under pressure at a flow rate which is sufficient to enable the gas stream to be supersonic in the diverging section, . the longitudinal axis of the outlet slot is disposed substantially parallel to the treatment surface, . and the nozzle is moved essentially by translation along a direction which is parallel to the treatment surface, and which may possibly be substantially perpendicular to the longitudinal axis of the outlet slot of the nozzle.
This process may be used for example for stripping surfaces.
For example, the projected particles may be particles based on starch or plastic material products.
The process of surface treatment according to the invention is particularly adapted for stripping a surface with a very precise outline or which is sensitive to attacks, for example the outside surface of a plane.
Other characteristics and advantages of the invention will appear during the following description of some embodiments, given by way of non-limiting examples, with reference to the annexed drawings.
In the drawings:
- Figure 1 is a cross-section view of a nozzle for surface treatment according to an embodiment of the invention, the cross-section being taken along line I-I of Figures 2 and 3, - Figure 2 is a view in elevation from the rear of the nozzle of Figure 1, - Figure 3 is a view in elevation taken from the front part of the nozzle of Figure 1, 2~7725~
- Figure 3A is a view similar to Figure 3, of a variant of the nozzle of Figures 1 to 3, - Figure 4 is a partial perspective view of the nozzle of Figures 1 to 3, in operation, - and Figure 5 is a schematic view of a device for a surface treatment including a nozzle such as the one of Figures 1 to 3.
The surface treatment nozzle of Figures 1 to 3 includes a central channel which extends longitudinally between an inlet opening 3 and an outlet opening 4.
The inlet opening 3 of the channel includes a housing 31 which is adapted to receive an end of a feeding duct which feeds up to the channel of the nozzle a gas stream under pressure carrying solid particles with possibly liquid droplets. This housing 31~ strictly speaking, does not constitute a part of the central channel of the nozzle, since it is not in contact with the gas stream under pressure nor with the solid particles which are carried by this gas stream.
From housing 31~ the central channel of the nozzle includes, in the direction of flow of the solid particles, first a converging section 6, then a diverging section 7.
The inlet opening 3 of the nozzle has a circular cross-section, and the converging section 6 has a cross-section which varies continuously between a circular cross-section at its upstream end, and a flattened cross-section, for example elliptical, at its downstream end, i.e. at the level of neck 5 which separates converging section 6 from diverging section 7. Thus, converging section 6 is progressively flattened between its upstream end and its downstream end.
~177250 On the other hand, the opening of outlet 4 of the nozzle is an elongated slot, and the diverging section 7 has on the other hand a cross-section which is flattened parallel to the outlet slot 4.
More specifically, in the specific example which is illustrated in the drawings, the diverging section 7 has, in the vicinity of neck 5, an elliptical cross-section which corresponds exactly to the cross-section of the upstream end of converging section 6.
This elliptical cross-section is progressively modified towards outlet slot 4 by slightly widening in the direction of the longitudinal axis 12 of the outlet slot, up to a given width 1 at the level of the outlet slot, and by increasing the thickness in the vicinity of the lateral edges 71 of the diverging section 7, until forming widened lateral parts 41 f thickness e at the level of the ends of outlet slot 4.
The ratio l/e may for example be higher than 2.
Possibly, as illustrated in Figure 4, diverging section 7 could eventually also include a progressive widening at its center, until also forming a widened part 42 at the center of outlet slot 4, this central widened part being separated from the lateral widened parts 41 by means of parts of narrower cross-section.
Neck 5 between converging section 6 and diverging section 7 consists of the line of intersection between the inner surfaces of said converging and diverging sections, so that the central channel of the nozzle contains no discontinuity in cross-section, i.e. no surface forming a sharp 217~2SO
obstacle to the flow of compressed gas or a sharp widening.
Moreover, the channel of the nozzle preferably includes a non-angular cross-section, even at the level of the lateral edges 71 f converging section 7, where the cross-section of the channel has a small radius of curvature.
The surface treatment nozzle of the invention may be manufactured in different manners. In the particular example illustrated in the drawings, this nozzle is made by molding two pieces 11 et 12, of a metallic material of high hardness, these two pieces being assembled according to a joint plane 13 which is parallel to longitudinal axis 12 of outlet slot 4, by means of screws 2.
When the surface treatment nozzle of the invention is in operation, solid particles are brought in a stream of compressed gas, for example compressed air under 2 to 3 bars, at the inlet of converging section 6.
This gas flow loaded with solid particles is accelerated in converging section 6, and in general becomes sonic at the level of neck 5, then is supersonic immediately downstream, so that it continues to be accelerated in diverging section 7.
For treating a surface 8, for example for stripping an outside surface of a plane, nozzle 1 is placed above surface 8, so that the longitudinal axis 12 of outlet slot 4 of the nozzle be disposed parallel to said surface 8. While solid particles are projected on surface 8 to strip the latter, i.e. for example to remove paint which covers said surface 8, nozzle 1 is moved essentially in translation according to direction 9, (in one way or thè other) parallel to surface 8 and in general, but not exclusively, f ~1772~0 perpendicularly to longitudinal axis 12 of outlet slot 4.
The movement of nozzle 1 may possibly include oscillations which are parallel to surface 8 and perpendicular to direction 9, however nozzle 1 is then always moved in translation, i.e. with its axis 12 always in the same direction.
In addition to its translation movement, it goes without saying that the nozzle may sometimes undergo movements causing a rotation of its axis 12, for example during repositioning operations.
Thus, the movement of surface treatment nozzle 1 produces a stripped mark 10 which is suitably treated along its entire width, without any attack of the underlying material of surface 8 at the center of mark 10.
Preferably, and for example when the treatment surface 8 should preserve a shape which is extremely precise or is formed of a delicate material (composite material or undercoating for example~, the projected particles may for example be particles based on plastic material products or starch products, for example particles of wheat starch.
The surface treatment nozzle 1 according to the invention may for example be used in surface treatment device 20 illustrated in Figure 5.
This device includes a working head 21 constituting an enclosure which is open towards the treatment surface 8, and the outlet of nozzle 1 opens inside this enclosure.
The working head 21 is kept applied against surface 8, or in the vicinity of surface 8, and it is also moved along surface 8 by means of a positioning system 22 which may be of any known type.
In the illustrated example, positioning system 22 includes a guiding beam 23 which may be kept fixed during the operation of nozzle 1, a carriage 24 moveable along guiding beam 23, a robotized articulated arm 25 which is fixed to carriage 24, and compressed air hydraulic cylinders 26 which maintain working head 21 against surface 8.
Possibly, guiding beam 23 may be mounted at the end of an articulated arrow carried by a vehicle (not illustrated).
Inlet 3 of nozzle 1 is supplied with compressed gas, for example compressed air, loaded with solid particles, by means of a feeding duct 30 which is connected on the one hand to a compressor 31, and on the other hand to a feeding hopper 32 containing a supply of solid particles.
Preferably, working head 21 is also connected to a section duct 33 to collect solid particles after their projection, this section duct 33 being connected to a suction turbine 34 by means of a collecting hopper 35 which receives the sucked solid particles.
The solid particles which have been collected in hopper 35 may be recycled towards feeding hopper 32, in which case they preferably pass through a system of separation 36 which may for example separate by sieving the particles which are too large or too small, by centrifugation for the particles which are too heavy, and possibly by magnetizing for the metallic particles, to send these separated particles to reject 37. Separation system 36 may additionally receive new solid particles from a supply 38.
Preferably, compressor 31 supplies nozzle 1 with a gas flow rate which is sufficient to ensure 21~72~0 that the flow of gas in nozzle 1 is sonic at the level of neck 5 and supersonic in the diverging section 7.
SURFACE TREATMENT NOZZLE AND METHOD AND DEVICE FOR
SURFACE TREATMENT USING SUCH A NOZZLE.
The present invention concerns a surface treatment nozzle, as well as a method and a device for surface treatment utilizing such a nozzle, for example for stripping one or more layers of paint or another coating provided on a surface, such as the outside surface of a plane.
In particular, the present invention relates to a surface treatment nozzle intended for projecting solid particles carried in a gas stream under pressure, this nozzle being provided with a single inlet for receiving the solid particles mixed to the gas stream under pressure and a single outlet to project the solid particles, the outlet having the shape of an elongated slot which has a longitudinal axis and extend along this longitudinal axis between two ends, the nozzle including a channel having, in the direction of flow of the solid particles, first a converging section which communicates with the inlet of the nozzle, then a divergent section which opens outside the nozzle through the outlet slot and which has along its entire length a section of a shape which is flattened parallel to said outlet slot, the diverging section additionally having two lateral edges which extend along said diverging section each up to an end of the outlet slot.
A nozzle of this type is disclosed in the document GB-A-2 191 127.
This known nozzle however has the disadvantage that the efficiency of the surface treatment is not equally distributed along the entire width of the nozzle, this efficiency being high at the 21772S~
center of the nozzle and low along the sides of the nozzle jet.
Thus, during stripping operations for example, when such a surface treatment nozzle is moved above a surface which is covered with paint while projecting solid particles, it leaves behind it a stripped mark in the form of a band whose median line has undergone a high stripping, due to the fact that it has been exposed for a long time to the stripping operation and that it has received the solid particles with higher energy, and whose sides are little or badly stripped, due to the fact that they have been exposed for a short time to the projected solid particles and that they have received solid particles projected with lower energy.
This disadvantage requires:
- either to move the surface treatment nozzle at a speed which is sufficiently low for the sides of the stripped mark to be suitably stripped, which slows down the stripping process and may additionally damage the surface which carries paint at the center of the stripped mark, if this surface is sensitive to attacks, for example if this surface is made of a composite material or an undercoat which is deposited on a solid material, - either to redo the edges of the marks already stripped, to suitably strip these edges, which also slows down the stripping process.
Moreover, the nozzle disclosed in the document mentioned above presents a section discontinuity which may result in a rapid wear of the nozzle and which produces turbulences which also disturb the efficiency of the stripping operation, such as when the nozzle is used at important gas ~1 7725~
speeds, and in particular supersonic speeds in the diverging section.
The present invention aims for example to overcome these disadvantages.
For this purpose, according to the invention, a surface treatment nozzle of the type mentioned above is essentially characterized in that the channel has progressing variations of cross-section along its entire length, in that the converging section has a downstream end which has a cross-section which is flattened parallel to the outlet slot, and in that the diverging section has, at least towards the outlet slot, two lateral parts of widened cross-section respectively in the vicinity of the two lateral edges, these two lateral parts of widened cross-section being separated by at least one part of narrower cross-section.
Thus, when the surface treatment nozzle according to the invention is moved above a surface, for example perpendicularly to its outlet slot, by projecting solid particles on this surface, this nozzle leaves behind it a treated mark in which all the points have received particles which have substantially the same kinetic energy and have been exposed to said particles during a substantially identical period. Consequently, the surface treatment is of the same quality along the entire width of the treated mark.
With the surface treatment nozzle according to the invention, it is for example possible to strip a layer of paint which covers an underlying surface made of an undercoating, a composite material or another material without in no way deteriorating said underlying surface.
According to advantageous embodiments, either or all the following provisions may be additionally used:
- the converging section has an upstream end which has a circular cross-section;
- the diverging section includes, substantially along its entire length, said two lateral parts of widened cross-section;
- the diverging section has, at least in the vicinity of its outlet slot, a central part of widened cross-section which is separated from each lateral part of widened cross-section by a part of narrower cross-section, so as to further optimize the equalization of the kinetic energy of the particles which are projected by the nozzle along the entire width of the outlet slot, It is also an object of the present invention to provide a device for a surface treatment including a nozzle as defined above and feeding means to send at the inlet of the nozzle the solid particles mixed with the gas stream under pressure, with a sufficient flow rate to enable the gas stream to be supersonic in the diverging section.
It is also an object of the present 25 invention to provide a surface treatment device including a nozzle such as defined above and positioning means for moving the nozzle essentially in translation along a treatment surface, It is also an object of the present invention to provide a process of surface treatment by projection of solid particles carried in a gas stream under pressure, in which:
. the particles are projected by means of a nozzle such as defined above, . the nozzle is supplied with the mixture of solid particles in the gas stream under pressure at a flow rate which is sufficient to enable the gas stream to be supersonic in the diverging section, . the longitudinal axis of the outlet slot is disposed substantially parallel to the treatment surface, . and the nozzle is moved essentially by translation along a direction which is parallel to the treatment surface, and which may possibly be substantially perpendicular to the longitudinal axis of the outlet slot of the nozzle.
This process may be used for example for stripping surfaces.
For example, the projected particles may be particles based on starch or plastic material products.
The process of surface treatment according to the invention is particularly adapted for stripping a surface with a very precise outline or which is sensitive to attacks, for example the outside surface of a plane.
Other characteristics and advantages of the invention will appear during the following description of some embodiments, given by way of non-limiting examples, with reference to the annexed drawings.
In the drawings:
- Figure 1 is a cross-section view of a nozzle for surface treatment according to an embodiment of the invention, the cross-section being taken along line I-I of Figures 2 and 3, - Figure 2 is a view in elevation from the rear of the nozzle of Figure 1, - Figure 3 is a view in elevation taken from the front part of the nozzle of Figure 1, 2~7725~
- Figure 3A is a view similar to Figure 3, of a variant of the nozzle of Figures 1 to 3, - Figure 4 is a partial perspective view of the nozzle of Figures 1 to 3, in operation, - and Figure 5 is a schematic view of a device for a surface treatment including a nozzle such as the one of Figures 1 to 3.
The surface treatment nozzle of Figures 1 to 3 includes a central channel which extends longitudinally between an inlet opening 3 and an outlet opening 4.
The inlet opening 3 of the channel includes a housing 31 which is adapted to receive an end of a feeding duct which feeds up to the channel of the nozzle a gas stream under pressure carrying solid particles with possibly liquid droplets. This housing 31~ strictly speaking, does not constitute a part of the central channel of the nozzle, since it is not in contact with the gas stream under pressure nor with the solid particles which are carried by this gas stream.
From housing 31~ the central channel of the nozzle includes, in the direction of flow of the solid particles, first a converging section 6, then a diverging section 7.
The inlet opening 3 of the nozzle has a circular cross-section, and the converging section 6 has a cross-section which varies continuously between a circular cross-section at its upstream end, and a flattened cross-section, for example elliptical, at its downstream end, i.e. at the level of neck 5 which separates converging section 6 from diverging section 7. Thus, converging section 6 is progressively flattened between its upstream end and its downstream end.
~177250 On the other hand, the opening of outlet 4 of the nozzle is an elongated slot, and the diverging section 7 has on the other hand a cross-section which is flattened parallel to the outlet slot 4.
More specifically, in the specific example which is illustrated in the drawings, the diverging section 7 has, in the vicinity of neck 5, an elliptical cross-section which corresponds exactly to the cross-section of the upstream end of converging section 6.
This elliptical cross-section is progressively modified towards outlet slot 4 by slightly widening in the direction of the longitudinal axis 12 of the outlet slot, up to a given width 1 at the level of the outlet slot, and by increasing the thickness in the vicinity of the lateral edges 71 of the diverging section 7, until forming widened lateral parts 41 f thickness e at the level of the ends of outlet slot 4.
The ratio l/e may for example be higher than 2.
Possibly, as illustrated in Figure 4, diverging section 7 could eventually also include a progressive widening at its center, until also forming a widened part 42 at the center of outlet slot 4, this central widened part being separated from the lateral widened parts 41 by means of parts of narrower cross-section.
Neck 5 between converging section 6 and diverging section 7 consists of the line of intersection between the inner surfaces of said converging and diverging sections, so that the central channel of the nozzle contains no discontinuity in cross-section, i.e. no surface forming a sharp 217~2SO
obstacle to the flow of compressed gas or a sharp widening.
Moreover, the channel of the nozzle preferably includes a non-angular cross-section, even at the level of the lateral edges 71 f converging section 7, where the cross-section of the channel has a small radius of curvature.
The surface treatment nozzle of the invention may be manufactured in different manners. In the particular example illustrated in the drawings, this nozzle is made by molding two pieces 11 et 12, of a metallic material of high hardness, these two pieces being assembled according to a joint plane 13 which is parallel to longitudinal axis 12 of outlet slot 4, by means of screws 2.
When the surface treatment nozzle of the invention is in operation, solid particles are brought in a stream of compressed gas, for example compressed air under 2 to 3 bars, at the inlet of converging section 6.
This gas flow loaded with solid particles is accelerated in converging section 6, and in general becomes sonic at the level of neck 5, then is supersonic immediately downstream, so that it continues to be accelerated in diverging section 7.
For treating a surface 8, for example for stripping an outside surface of a plane, nozzle 1 is placed above surface 8, so that the longitudinal axis 12 of outlet slot 4 of the nozzle be disposed parallel to said surface 8. While solid particles are projected on surface 8 to strip the latter, i.e. for example to remove paint which covers said surface 8, nozzle 1 is moved essentially in translation according to direction 9, (in one way or thè other) parallel to surface 8 and in general, but not exclusively, f ~1772~0 perpendicularly to longitudinal axis 12 of outlet slot 4.
The movement of nozzle 1 may possibly include oscillations which are parallel to surface 8 and perpendicular to direction 9, however nozzle 1 is then always moved in translation, i.e. with its axis 12 always in the same direction.
In addition to its translation movement, it goes without saying that the nozzle may sometimes undergo movements causing a rotation of its axis 12, for example during repositioning operations.
Thus, the movement of surface treatment nozzle 1 produces a stripped mark 10 which is suitably treated along its entire width, without any attack of the underlying material of surface 8 at the center of mark 10.
Preferably, and for example when the treatment surface 8 should preserve a shape which is extremely precise or is formed of a delicate material (composite material or undercoating for example~, the projected particles may for example be particles based on plastic material products or starch products, for example particles of wheat starch.
The surface treatment nozzle 1 according to the invention may for example be used in surface treatment device 20 illustrated in Figure 5.
This device includes a working head 21 constituting an enclosure which is open towards the treatment surface 8, and the outlet of nozzle 1 opens inside this enclosure.
The working head 21 is kept applied against surface 8, or in the vicinity of surface 8, and it is also moved along surface 8 by means of a positioning system 22 which may be of any known type.
In the illustrated example, positioning system 22 includes a guiding beam 23 which may be kept fixed during the operation of nozzle 1, a carriage 24 moveable along guiding beam 23, a robotized articulated arm 25 which is fixed to carriage 24, and compressed air hydraulic cylinders 26 which maintain working head 21 against surface 8.
Possibly, guiding beam 23 may be mounted at the end of an articulated arrow carried by a vehicle (not illustrated).
Inlet 3 of nozzle 1 is supplied with compressed gas, for example compressed air, loaded with solid particles, by means of a feeding duct 30 which is connected on the one hand to a compressor 31, and on the other hand to a feeding hopper 32 containing a supply of solid particles.
Preferably, working head 21 is also connected to a section duct 33 to collect solid particles after their projection, this section duct 33 being connected to a suction turbine 34 by means of a collecting hopper 35 which receives the sucked solid particles.
The solid particles which have been collected in hopper 35 may be recycled towards feeding hopper 32, in which case they preferably pass through a system of separation 36 which may for example separate by sieving the particles which are too large or too small, by centrifugation for the particles which are too heavy, and possibly by magnetizing for the metallic particles, to send these separated particles to reject 37. Separation system 36 may additionally receive new solid particles from a supply 38.
Preferably, compressor 31 supplies nozzle 1 with a gas flow rate which is sufficient to ensure 21~72~0 that the flow of gas in nozzle 1 is sonic at the level of neck 5 and supersonic in the diverging section 7.
Claims (11)
1. Surface treatment nozzle adapted for projecting solid particles carried in a gas stream under pressure, this nozzle being provided with a single inlet (3) to receive the solid particles mixed to the gas stream under pressure and a single outlet (4) to project the solid particles, the outlet (4) having the shape of an elongated slot which has a longitudinal axis (12) and extends along this longitudinal axis between two ends, the nozzle including a channel (6, 7) having, in the direction of flow of the solid particles, first a converging section (6) which communicates with the inlet (3) of the nozzle, and a diverging section (7) which opens outside the nozzle through the outlet slot (4) and which has along its entire length a cross-section of flattened shape which is parallel to said outlet slot, the diverging section additionally having two lateral edges (71) which extend along said diverging section each until reaching an end of the outlet slot, characterized in that the channel (6, 7) has progressive variations of cross-section along its entire length, in that the converging section (6) has a downstream end (5) which has a cross-section which is flattened parallel to the outlet slot (4), and in that the diverging section (7) has, at least towards its outlet slot (4), two lateral parts of widened cross-section (41) respectively in the vicinity of the two lateral edges (71), these two lateral parts of widened cross-section being separated by at least one part of narrower cross-section.
2. Nozzle according to claim 1, in which the converging section includes an upstream end which has a circular cross-section.
3. Nozzle according to any one of claims 1 and 2, in which the diverging section (7) has, substantially along its entire length, said two lateral parts of widened cross-section (41)
4. Nozzle according to any one of claims 1 to 3, in which the diverging section (7) additionally has, at least in the vicinity of its outlet slot (4), a central part of widened cross-section (42) which is separated from each lateral part of widened cross-section (41) by means of a part of narrower cross-section.
5. Device for surface treatment including a surface treatment nozzle according to any one of the preceding claims, and feeding means for supplying at the inlet (3) of the nozzle, solid particles mixed to the gas stream under pressure, with a sufficient flow rate to enable the gas stream to be supersonic in the diverging section (7).
6. Device for surface treatment, including a surface treatment nozzle according to any one of claims 1 to 4, and positioning means (22) to move the nozzle essentially in translation along a treated surface (8).
7. Process for surface (8) treatment by projecting solid particles carried in a gas stream under pressure, in which:
- the particles are projected by means of a nozzle provided with a single inlet (3) to receive the solid particles mixed to the gas stream under pressure and a single outlet (4) for projecting the solid particles, the outlet (4) having the shape of an elongated slot which has a longitudinal axis (12) and extends along this longitudinal axis between two ends, the nozzle including a channel (6, 7) having, in the direction of flow of the solid particles, first a converging section (6) which communicates with the inlet (3) of the nozzle, and a diverging section (7) which opens outside the nozzle by means of the outlet slot (4) and which has along its entire length a cross-section of flattened shape parallel to said outlet slot, the channel (6, 7) having variations of progressive cross-section along its length, the converging section (6) having a downstream end (5) which has a cross-section which is flattened parallel to the outlet slot (4), and the diverging section (7) having two lateral edges (71) which extend along said diverging section each up to an end of the outlet slot (4), the diverging section (7) including at least towards its outlet slot (4), two parts of widened cross-section (41) respectively in the vicinity of the two lateral edges (71), these two parts of widened cross-section being separated by at least one part of narrower cross-section, - the nozzle is supplied with the mixture of solid particles in the gas stream under pressure at a flow rate which is sufficient to enable the gas stream to be supersonic in the diverging section (7), - the longitudinal axis (12) of the outlet slot (4) is disposed substantially parallel to the treatment surface (8), - and the nozzle is essentially moved in translation along a direction (9) which is parallel to the surface treatment (8).
- the particles are projected by means of a nozzle provided with a single inlet (3) to receive the solid particles mixed to the gas stream under pressure and a single outlet (4) for projecting the solid particles, the outlet (4) having the shape of an elongated slot which has a longitudinal axis (12) and extends along this longitudinal axis between two ends, the nozzle including a channel (6, 7) having, in the direction of flow of the solid particles, first a converging section (6) which communicates with the inlet (3) of the nozzle, and a diverging section (7) which opens outside the nozzle by means of the outlet slot (4) and which has along its entire length a cross-section of flattened shape parallel to said outlet slot, the channel (6, 7) having variations of progressive cross-section along its length, the converging section (6) having a downstream end (5) which has a cross-section which is flattened parallel to the outlet slot (4), and the diverging section (7) having two lateral edges (71) which extend along said diverging section each up to an end of the outlet slot (4), the diverging section (7) including at least towards its outlet slot (4), two parts of widened cross-section (41) respectively in the vicinity of the two lateral edges (71), these two parts of widened cross-section being separated by at least one part of narrower cross-section, - the nozzle is supplied with the mixture of solid particles in the gas stream under pressure at a flow rate which is sufficient to enable the gas stream to be supersonic in the diverging section (7), - the longitudinal axis (12) of the outlet slot (4) is disposed substantially parallel to the treatment surface (8), - and the nozzle is essentially moved in translation along a direction (9) which is parallel to the surface treatment (8).
8. Process for surface treatment according to claim 7, in which the direction (9) of translation of nozzle (1) is substantially perpendicular to the longitudinal axis (12) of the outlet slot of the nozzle.
9. Process for surface treatment according to any one of claims 7 and 8, in which the surface treatment is a stripping.
10. Process for surface treatment according to claim 9, in which the particles which are projected are selected from: starch base particles and plastic material base particles.
11. Process for surface treatment according to any one of claims 9 and 10, in which the surface to be stripped is the outside surface of a plane.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| FR93/14190 | 1993-11-26 | ||
| FR9314190A FR2712826A1 (en) | 1993-11-26 | 1993-11-26 | Surface treatment nozzle, and surface treatment method using such a nozzle. |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2177250A1 true CA2177250A1 (en) | 1995-06-01 |
Family
ID=9453275
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002177250A Abandoned CA2177250A1 (en) | 1993-11-26 | 1994-11-25 | Surface treatment nozzle and method and device for surface treatment using such a nozzle |
Country Status (7)
| Country | Link |
|---|---|
| EP (1) | EP0730498B1 (en) |
| AT (1) | ATE164785T1 (en) |
| AU (1) | AU1192395A (en) |
| CA (1) | CA2177250A1 (en) |
| DE (1) | DE69409542T2 (en) |
| FR (1) | FR2712826A1 (en) |
| WO (1) | WO1995014536A1 (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| AUPP860999A0 (en) * | 1999-02-10 | 1999-03-04 | Southern Rubber Pty Ltd | Ultra high pressure liquid jet nozzle |
| US6293857B1 (en) * | 1999-04-06 | 2001-09-25 | Robert Pauli | Blast nozzle |
| GB2372718B (en) * | 2001-01-04 | 2004-07-14 | Workinter Ltd | Nozzle intended for the concentrated distribution of a fluid for scouring of surfaces |
| CN103774529A (en) * | 2014-01-20 | 2014-05-07 | 南通东南公路工程有限公司 | Plate type spreading mechanism |
| DE102023119415A1 (en) * | 2023-07-21 | 2025-01-23 | Alfred Kärcher SE & Co. KG | FLAT JET NOZZLE ARRANGEMENT |
Family Cites Families (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR737521A (en) * | 1932-03-17 | 1932-12-13 | Quiet sprayer for air humidification by steam | |
| GB606036A (en) * | 1945-01-01 | 1948-08-05 | Alick Clarkson | Venturi cleaning nozzle |
| US2605596A (en) * | 1949-11-10 | 1952-08-05 | William C Uhri | Method of cleaning surfaces |
| FR1087496A (en) * | 1952-08-11 | 1955-02-24 | Nozzle usable in particular for projecting abrasive materials entrained by an air jet | |
| US2971250A (en) * | 1952-12-19 | 1961-02-14 | Spraying Systems Co | Spray nozzle with contoured orifice and method of contouring the orifice |
| EP0231187A4 (en) * | 1984-10-29 | 1988-05-31 | Hardblast Australia Pty Ltd | Nozzle for sand blasting. |
| GB2191127A (en) * | 1986-06-02 | 1987-12-09 | Laing & Sons Ltd James | Grit-blasting nozzle |
| FR2622814A1 (en) * | 1987-11-05 | 1989-05-12 | Collard Catherine | Water spray (diffuser) characterised by the possibility of rapid cleaning without interruption of the water jet |
| DE9209724U1 (en) * | 1992-07-20 | 1992-11-26 | Pocanschi, Adrian, Dr.-Ing., 7000 Stuttgart | Jet nozzle |
-
1993
- 1993-11-26 FR FR9314190A patent/FR2712826A1/en not_active Withdrawn
-
1994
- 1994-11-25 AT AT95902800T patent/ATE164785T1/en not_active IP Right Cessation
- 1994-11-25 WO PCT/FR1994/001380 patent/WO1995014536A1/en not_active Ceased
- 1994-11-25 AU AU11923/95A patent/AU1192395A/en not_active Abandoned
- 1994-11-25 DE DE69409542T patent/DE69409542T2/en not_active Expired - Fee Related
- 1994-11-25 CA CA002177250A patent/CA2177250A1/en not_active Abandoned
- 1994-11-25 EP EP95902800A patent/EP0730498B1/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| DE69409542D1 (en) | 1998-05-14 |
| AU1192395A (en) | 1995-06-13 |
| DE69409542T2 (en) | 1998-10-29 |
| WO1995014536A1 (en) | 1995-06-01 |
| FR2712826A1 (en) | 1995-06-02 |
| EP0730498B1 (en) | 1998-04-08 |
| ATE164785T1 (en) | 1998-04-15 |
| EP0730498A1 (en) | 1996-09-11 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FZDE | Discontinued |