EP0070002B1 - Blasting apparatus, in particular for abrasive blasting by compressed air - Google Patents

Blasting apparatus, in particular for abrasive blasting by compressed air Download PDF

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Publication number
EP0070002B1
EP0070002B1 EP82106144A EP82106144A EP0070002B1 EP 0070002 B1 EP0070002 B1 EP 0070002B1 EP 82106144 A EP82106144 A EP 82106144A EP 82106144 A EP82106144 A EP 82106144A EP 0070002 B1 EP0070002 B1 EP 0070002B1
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EP
European Patent Office
Prior art keywords
blasting
jet
nozzle
appliance according
area
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.)
Expired
Application number
EP82106144A
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German (de)
French (fr)
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EP0070002A1 (en
Inventor
Karl Christian Ing. Glaeser
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Ernst Peiniger GmbH Unternehmen fur Bautenschutz
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Ernst Peiniger Unternehmen fur Bautenschutz GmbH
Ernst Peiniger GmbH Unternehmen fur Bautenschutz
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Application filed by Ernst Peiniger Unternehmen fur Bautenschutz GmbH, Ernst Peiniger GmbH Unternehmen fur Bautenschutz filed Critical Ernst Peiniger Unternehmen fur Bautenschutz GmbH
Priority to AT82106144T priority Critical patent/ATE16083T1/en
Publication of EP0070002A1 publication Critical patent/EP0070002A1/en
Application granted granted Critical
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    • 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
    • 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

Definitions

  • the invention relates to a blasting device, in particular for compressed air blasting, with a hose-like feed line that can be connected on the inlet side to a source for a mixture of compressed carrier air and a blasting agent, with a substantially constant internal cross-section and with a blasting nozzle that can be connected to the outlet line on the outlet side, the blasting nozzle being one Elongated, narrowing from the inner cross section of the supply line to a nozzle constriction area and possibly an extension area adjoining the nozzle constriction area and is at least partially composed of several rigid and preferably straight, interconnected pipe sections, and the interior of the pipe sections being an imaginary, possibly represent rejuvenating or expanding body.
  • a granular blasting medium usually sand
  • a blasting device against a surface to be treated with the aid of a stream of air.
  • the aim is to achieve high speeds of impact of the granular abrasive on the surface to be treated.
  • the exit velocity of the grains of the blasting medium emerging from the nozzle area is frequently above 100 m / sec.
  • the mixture of the carrier air and the blasting medium is under high pressure in relation to the atmosphere in the feed line, but the speed of the flight promotion of the granular blasting medium is low.
  • the pressure of the air in the nozzle area is converted into kinetic energy in a known manner, as described in the Bernoulli equation. Due to the high velocity of the air flow forced in the nozzle constriction, the individual bodies of the abrasive are also accelerated at this point. Inevitably, however, the speed of the grains of the abrasive is never greater than the speed of the air flow and in practice even much lower than the speed of the air flow.
  • the blasting nozzle In the known blasting device from which the invention is based (cf. CH-A-131 161), the blasting nozzle consists of a jacket made of a soft material and a lining lining the jacket made of a highly wear-resistant material.
  • the lining made of a highly wear-resistant material is divided several times due to the larger dimensions of the jet nozzle.
  • the jacket serves to hold the parts of the feed together.
  • the individual parts of the chuck come into direct contact with one another, so that the jet nozzle as a whole is rigidly elongated.
  • a high exit velocity of the grains of the blasting medium from the nozzle area is achieved in that the constriction area, i.e. the area in which the pressure of the air flow is converted into kinetic energy, is relatively long (cf. DE-A1 -2843013).
  • the path available to accelerate the grains of the blasting medium becomes so large that the speed of the grains at the end of this acceleration path, that is to say behind the nozzle constriction, lies in the range of the speed of the air. If the speed of the air flow emerging from the nozzle area is to be in the range or above the speed of sound of the air, an expansion area must be provided so that a Laval nozzle is formed overall.
  • the grains of the abrasive also accelerate further.
  • the constriction area is made relatively long, the nozzle area is given a considerable overall length. This disadvantage has already been recognized.
  • the invention has for its object to provide a practical blasting device, i.e. a blasting device in which the advantages of an elongated constriction area can be used, in which at the same time a practice-oriented action of the blasting nozzle is possible and finally the wear is kept as low as possible.
  • the blasting device in which the above-mentioned object is achieved, is there characterized in that the pipe sections are separated from one another by annular spaces and are connected to one another in the manner of a polygon by means of joint parts, and the joint parts are arranged in the radial direction outside the imaginary body in the regions of the annular spaces.
  • the blasting nozzle can be bent in the area composed of individual pipe pieces, in particular the constriction area, so that this blasting nozzle with an elongated constriction area is considerably easier to handle than the blasting nozzle in the known blasting device from which the invention is based.
  • the air stream loaded with blasting agent is deflected practically only in the area of the joint parts.
  • the joint parts themselves are effectively protected against wear by being outside the actual path of the air stream loaded with blasting media. Only the straight pipe sections, in particular their ends at the front in the direction of flight of the grains of the blasting medium, must be designed to be resistant to abrasion.
  • the axial width of the annular gaps is related to the wall thickness of the pipe sections insofar as the maximum possible bend of the blasting nozzle given by the width of the gaps must not lead to the joint parts being able to be reached directly by grains of the blasting medium. But this is related to the radial depth of the gaps, that is, the wall thickness of the pipe sections.
  • a blasting device is already known in which the blasting nozzle is composed of a plurality of rigid, straight, interconnected pipe sections, the pipe sections are connected to one another in the manner of a polygon and the joint parts are arranged outside the pipe sections (cf. DE-C 698 841) .
  • this is a jet nozzle with a substantially uniform internal cross-section, that is to say not with a narrowing region tapering towards a nozzle constriction and an expansion region adjoining the nozzle constriction.
  • It is essential for this known blasting device that the individual pipe sections come into direct contact with one another, so that when the blasting nozzle is bent, the effective cross section for the carrying air loaded with blasting medium is narrowed in stages.
  • This known blasting device has consequently not been able to suggest the blasting device according to the invention in which the pipe sections are deliberately separated from one another by annular spaces.
  • a particularly advantageous embodiment of the blasting device according to the invention is given in that the expansion area has twice to three times, preferably two and a half times the length of the constriction area.
  • the expansion area has twice to three times, preferably two and a half times the length of the constriction area.
  • the blasting device it may be advisable to manufacture at least a portion of the constriction area that is connected to the feed line from a resilient material, for example to form it in one piece with the feed line.
  • a resilient material for example to form it in one piece with the feed line.
  • the speed of the grains of the abrasive is so low that the abrasive effect can be neglected.
  • the advantages of the polygonal section of the nozzle area are thus particularly evident in the areas of high speed of the grains of the blasting medium, that is to say in the vicinity of the outlet end of the nozzle area. Therefore, the part of the constriction area adjacent to the nozzle constriction area and the entire extension area should be constructed from a polygonal section.
  • the joint parts of the blasting device can be designed as ball-and-socket joints, the individual balls each having an inner passage for the stream of carrier air loaded with the blasting agent.
  • Simple joints with a fixed swivel axis arranged transversely to the direction of flight of the blasting medium are also possible, it being advisable to offset successive swivel axes by 90 ° so that movement in space is also possible.
  • elastic or resilient sleeves are available for connecting two rigid pipe sections. These do not have to be made of a material that is sufficiently abrasion-resistant, since they are completely outside the trajectory of the blasting medium.
  • a feed line 1 is connected to a nozzle area 2.
  • the supply line 1 is connected on the input side to a source (not shown) for a mixture of compressed air and a blasting agent; it is made from a resilient material and is therefore flexible.
  • the inner cross section of the feed line 1 is constant over the entire length and is designed in such a way that the blasting medium is promoted at low speed by the grains of this blasting medium.
  • the feed line 1 is connected to the nozzle area 2, which is composed of an elongated constriction area 3 and an extension area 4 that continues this. Between the two is a nozzle constriction 5, the point of the smallest internal cross section of the entire arrangement.
  • the nozzle area 2 consists of a total of ten individual, rigid and straight pipe pieces 6, 7 and 8, the inner wall of which is shaped and which are arranged in such a way that they represent an imaginary, uniformly tapering and subsequently expanding body when the nozzle area 2 is straight.
  • this body is composed of two truncated cones, which lie against one another with their circular area of smaller diameter - namely the diameter of the nozzle constriction 5.
  • This imaginary body contains the trajectories of the grains of the abrasive.
  • the individual pipe sections 6 and 8 are arranged one behind the other in such a way that an annular space 9 remains free.
  • the length of the space 9 is about 20% of the length of a single piece of pipe 6,7,8. This creates free spaces for articulated movement between the rigid pipe sections 6, 7, 8.
  • the total of ten pipe sections 6, 7, 8 are coated on the outside with a jacket 10, which ensures the relative arrangement of the individual pipe sections 6, 7, 8.
  • the jacket 10 merges in one piece into the feed line 1.
  • the material of the jacket 10 has the same elastic and resilient properties as the feed line 1.
  • the areas of the jacket 10 located outside the annular spaces 9 allow articulation between adjacent pipe sections 6, 7, 8 and thus form the articulated parts 11.
  • each Such a joint part 11 is limited in that the annular space 9 closes at one point when adjacent pipe sections 6, 7 abut one another.
  • the end edges of opposite pipe sections 6, 7, 8 are chamfered in such a way that the annular space 9 widens outward in a V-shape. As a result, the edges of small diameter initially come into contact with opposite pipe sections 6, 7, 8 at the maximum bending angle.
  • the annular spaces 9 form a discontinuity and thus interfere with the passage of the air stream loaded with the abrasive, but they enable the joint parts 11, which are formed from a relatively inexpensive and less abrasion-resistant material, to lie in the shadow areas of the air stream and thus are largely protected from the abrasive effect of the abrasive.
  • the annular spaces 9 fill more or less with grains of the blasting agent as deposits 12; these deposits 12 of the blasting agent protect the joint parts 11 of the jacket 10 against directly impacting, fast-flying granules of the blasting agent.
  • the tube pieces 6 of the constriction area 3 are designed as conical jacket rings converging in the direction of flight (arrow 13).
  • the pipe sections 8 of the expansion area 4 are conical casing rings.
  • the pipe section 7, in which the nozzle constriction 5 is formed, is both a part of the constriction area 3 and a part of the expansion area 4 and accordingly consists of a conically narrowing conical jacket ring and a conically expanding conical jacket ring.
  • the pipe sections 6, 7, 8 are made of a very abrasion-resistant material.
  • the jacket 10 is connected in a suitable manner to the outer walls of the pipe sections 6, 7; for example, it has shrunk.
  • the jacket 10 in particular its hinge parts 11, it may be advisable to arrange short coil springs between the individual pipe sections 6, 7, 8, which push the adjacent pipe sections 6, 7, 8 apart and thereby always keep the entire nozzle area 2 in its straight line Press shape.
  • the feed line 1 is shrunk onto the first pipe section 6, as seen in the direction of flight - (arrow 13) - of the grains of the blasting medium, so that the transition area between the feed line 1 and the nozzle area 2 is as smooth as possible and therefore practically does not affect the air flow.
  • the individual pipe sections 6 of the nozzle area 2 according to FIG. 2, which has only one constriction area 3, are connected to one another via joint parts 14 designed as bellows.
  • the joint parts 14, which are designed in particular as metallic bellows, have a certain spring characteristic, so that the straight shape shown is obtained when the nozzle region 2 is in the rest position.
  • the inlet ends 15 of the pipe sections 6 are rounded on the inside, so that when the joint parts 14 bend, there are no sharp edges opposite the air flow.
  • the joint parts 11 and 14 are each located outside the actual path of the flying abrasive grains. This is when choosing the Material for the joint parts 11, 14 only the elasticity or resilience, but not the abrasion resistance is decisive. Rather, it is to be regarded as a particular advantage of these two exemplary embodiments that the two mechanical functions - flexibility and abrasion resistance - are separated from one another.
  • the joint part 16 in the exemplary embodiment according to FIG. 3 comes into direct contact with the accelerated abrasive and must therefore be made of an abrasion-resistant material at least in the area of these contact points.
  • the joint part 16 is designed as a ball joint and is composed of a spherical body 17 with an inner passage 18, of spherical shells 19 on the adjacent tube pieces 6 and of a capsule 20.
  • the spherical body 17 forms the innermost part of this arrangement, its inner passage 18 narrows towards the center of the ball approximately diabolically and has two openings 21.
  • the diameter of the mouths 22 is - as will be explained later - so matched with the maximum swivel angle of each individual pipe section 6 and the diameter of the opening 21 that the mouth 22 can never be outside the opening 21.
  • the right pipe section 6 in FIG. 3 is deflected as far down as possible, the left pipe section 6 is in its central position.
  • An angle limitation is achieved in that the front outer surfaces of the spherical shell 19 abut against an impact 23 of the capsule 20.
  • the capsule 20 has holding areas 24 which press the spherical shells 19 against the spherical body 17 and thereby hold the joint part 16 together.
  • the total length of the constriction area 3 of a blasting device according to the invention is approximately 50 to 100 cm. Together with an expansion area 4 according to the invention, which is approximately two and a half times longer, the entire nozzle area 2 thus has a considerable length of approximately 1.75 m to 3.50 m. Such long nozzle areas 2 can, however, be handled if, as proposed here, they are designed in the manner of a polygon.

Abstract

1. A jet appliance, particularly for compressed air blasting, with a hose-like delivery pipe (1) of substantially constant internal cross-section that can be attached at its entry end to a source of a mixture of compressed transporting air and blasting medium and can be attached at its exit end to a blasting nozzle (2) which possesses an elongated constriction portion (3) narrowing down from the internal cross-section of the delivery pipe (1) to a jet restriction (5) and if required an expansion portion (4) attached to the jet restriction (5) and is at least partially assembled from several rigid and preferably straight tubular pieces (6, 7, 8) joined to one another and in which the interiors of the tubular pieces (6, 7, 8) represent an imaginary body, narrowing or expanding as the case may be, characterized in that the tubular pieces (6, 7, 8) are separated from one another by ring-shaped interspaces (9) and are connected together like the sides of a polygon by flexible couplings (11, 14, 16) that are located externally to the imaginary body in a radial direction in the areas of the ring-shaped interspaces (9).

Description

Die Erfindung betrifft ein Strahlgerät, insbesondere für das Druckluftstrahlen, mit einer eingangsseitig an eine Quelle für ein Gemisch aus komprimierter Tragluft und einem Strahlmittel anschliessbaren, schlauchartigen Zuleitung mit einem im wesentlichen konstanten Innenquerschnitt und mit einer ausgangsseitig an die Zuleitung anschliessbaren Strahldüse, wobei die Strahldüse einen langgestreckten, sich vom Innenquerschnitt der Zuleitung zu einer Düsenengstelle hin verjüngenden Verengungsbereich und ggf. einen sich an die Düsenengstelle anschliessenden Erweiterungsbereich aufweist und zumindest teilweise aus mehreren starren und vorzugsweise geraden, miteinander verbundenen Rohrstücken zusammengesetzt ist und wobei die Innenräume der Rohrstücke einen gedachten, sich ggf. verjüngenden bzw. erweiternden Körper darstellen.The invention relates to a blasting device, in particular for compressed air blasting, with a hose-like feed line that can be connected on the inlet side to a source for a mixture of compressed carrier air and a blasting agent, with a substantially constant internal cross-section and with a blasting nozzle that can be connected to the outlet line on the outlet side, the blasting nozzle being one Elongated, narrowing from the inner cross section of the supply line to a nozzle constriction area and possibly an extension area adjoining the nozzle constriction area and is at least partially composed of several rigid and preferably straight, interconnected pipe sections, and the interior of the pipe sections being an imaginary, possibly represent rejuvenating or expanding body.

Beim Druckluftstrahlen, das früher auch als Sandstrahlen bezeichnet worden ist und heute gelegentlich Freistrahlen genannt wird, wird ein körniges Strahlmittel, zumeist Sand, mit Hilfe eines Tragluftstromes aus dem Düsenbereich eines Strahlgerätes gegen eine zu behandelnde Oberfläche gefördert. Dabei werden hohe Auftreffgeschwindigkeiten des körnigen Strahlmittels auf der zu behandelnden Oberfläche angestrebt. Demzufolge liegt die Austrittsgeschwindigkeit der aus dem Düsenbereich austretenden Körner des Strahlmittels häufig über 100 m/sec.In compressed air blasting, which was formerly referred to as sandblasting and is nowadays sometimes called free blasting, a granular blasting medium, usually sand, is conveyed from the nozzle area of a blasting device against a surface to be treated with the aid of a stream of air. The aim is to achieve high speeds of impact of the granular abrasive on the surface to be treated. As a result, the exit velocity of the grains of the blasting medium emerging from the nozzle area is frequently above 100 m / sec.

In der Zuleitung befindet sich das Gemisch aus der Tragluft und dem Strahlmittel unter hohem Druck gegenüber der Atmosphäre, die Geschwindigkeit der Flugförderung des körnigen Strahlmittels ist jedoch gering. In bekannter Weise wird der Druck der Tragluft im Düsenbereich in kinetische Energie umgesetzt, wie dies die Bernoulli-Gleichung beschreibt. Aufgrund der in der Düsenengstelle erzwungenen hohen Geschwindigkeit des Tragluftstromes werden auch die einzelnen Körper des Strahlmittels an dieser Stelle beschleunigt. Zwangsläufig ist jedoch die Geschwindigkeit der Körner des Strahlmittels nie grösser als die Geschwindigkeit des Tragluftstromes und in der Praxis sogar wesentlich niedriger als die Geschwindigkeit des Tragluftstroms. Der Grund hierfür ist im sehr unterschiedlichen Massenverhältnis zwischen der Masse eines Kornes des Strahlmittels und der Masse eines entsprechend grossen Luftteilchens zu sehen. Aufgrund ihrer deutlich höheren Masse haben die Körner des Strahlmittels eine Trägheit. Trotz gleicher Beschleunigungskräfte ist die tatsächliche Beschleunigung eines Korns des Strahlmittels deutlich geringer als die Beschleunigung eines gleich grossen Luftteilchens.The mixture of the carrier air and the blasting medium is under high pressure in relation to the atmosphere in the feed line, but the speed of the flight promotion of the granular blasting medium is low. The pressure of the air in the nozzle area is converted into kinetic energy in a known manner, as described in the Bernoulli equation. Due to the high velocity of the air flow forced in the nozzle constriction, the individual bodies of the abrasive are also accelerated at this point. Inevitably, however, the speed of the grains of the abrasive is never greater than the speed of the air flow and in practice even much lower than the speed of the air flow. The reason for this can be seen in the very different mass ratio between the mass of a grain of the abrasive and the mass of a correspondingly large air particle. Due to their significantly higher mass, the grains of the abrasive have an inertia. Despite the same acceleration forces, the actual acceleration of a grain of the abrasive is significantly less than the acceleration of an air particle of the same size.

Bei dem bekannten Strahlgerät, von dem die Erfindung ausgeht (vgl. die CH-A-131 161), besteht die Strahldüse aus einem Mantel aus einem weichen Material und aus einem den Mantel auskleidenden Futter aus einem hochverschleissfesten Material. Das Futter aus einem hochverschleissfesten Material ist, der grösseren Abmessungen der Strahldüse wegen, mehrfach unterteilt. Der Mantel dient hierbei zum Zusammenhalten der Teile des Futters. Die einzelnen Teile des Futters kommen unmittelbar einander zur Anlage, so dass die Strahldüse insgesamt starr langgestreckt ausgebildet ist.In the known blasting device from which the invention is based (cf. CH-A-131 161), the blasting nozzle consists of a jacket made of a soft material and a lining lining the jacket made of a highly wear-resistant material. The lining made of a highly wear-resistant material is divided several times due to the larger dimensions of the jet nozzle. The jacket serves to hold the parts of the feed together. The individual parts of the chuck come into direct contact with one another, so that the jet nozzle as a whole is rigidly elongated.

Bei einem anderen bekannten Strahlgerät wird dadurch eine hohe Austrittgeschwindigkeit der Körner des Strahlmittels aus dem Düsenbereich erreicht, dass der Verengungsbereich, also der Bereich, in dem sich der Druck des Tragluftstromes in kinetische Energie umsetzt, relativ lang ausgebildet ist (vgl. die DE-A1-2843013). Dadurch wird die zur Beschleunigung der Körner des Strahlmittels zur Verfügung stehende Wegstrecke so gross, dass die Geschwindigkeit der Körner am Ende dieser Beschleunigungsstrecke, also hinter der Düsenengstelle, im Bereich der Geschwindigkeit der Tragluft liegt. Wenn die Geschwindigkeit des aus dem Düsenbereich austretenden Tragluftstromes im Bereich oder oberhalb der Schallgeschwindigkeit der Luft liegen soll, muss ein Erweiterungsbereich vorgesehen werden, so dass insgesamt eine Laval-Düse gebildet wird. Auch in diesem Erweiterungsbereich findet eine weitere Beschleunigung der Körner des Strahlmittels statt. Bildet man jedoch den Verengungsbereich relativ lang aus, erhält der Düsenbereich eine beträchtliche Gesamtlänge. Dieser Nachteil ist bereits erkannt worden. Um ihn zu mindern, ist bereits vorgeschlagen worden, den Verengungsbereich zumindest teilweise aus dem Material zu fertigen, aus dem auch die nachgiebige Zuleitung, die meist als Schlauch ausgeführt ist, gefertigt ist. Dadurch wird erreicht, dass zumindest ein Teilstück des langen Verengungsbereichs biegsam ist, auch wenn diese Biegsamkeit geringer ist als die Biegsamkeit der Zuleitung.In another known blasting device, a high exit velocity of the grains of the blasting medium from the nozzle area is achieved in that the constriction area, i.e. the area in which the pressure of the air flow is converted into kinetic energy, is relatively long (cf. DE-A1 -2843013). As a result, the path available to accelerate the grains of the blasting medium becomes so large that the speed of the grains at the end of this acceleration path, that is to say behind the nozzle constriction, lies in the range of the speed of the air. If the speed of the air flow emerging from the nozzle area is to be in the range or above the speed of sound of the air, an expansion area must be provided so that a Laval nozzle is formed overall. In this expansion area, the grains of the abrasive also accelerate further. However, if the constriction area is made relatively long, the nozzle area is given a considerable overall length. This disadvantage has already been recognized. In order to reduce it, it has already been proposed to manufacture the constriction area at least partially from the material from which the flexible feed line, which is usually designed as a hose, is also made. This ensures that at least a portion of the long constriction area is flexible, even if this flexibility is less than the flexibility of the feed line.

Insgesamt hat die Fachwelt die Vorteile von relativ lang ausgebildeten Verengungsbereichen zwar erkannt, eine von der Praxis angenommene Ausführung dieser Lehre fehlt jedoch noch. Starr ausgebildete Düsenbereiche, bei denen ein langer Verengungsbereich verwirklicht ist, sind in der Praxis zu unhandlich. Die bislang vorgeschlagenen Düsenbereiche mit nachgiebigem Verengungsbereich weisen immer dann einen sehr hohen Verschleiss auf, wenn der Düsenbereich im praktischen Einsatz gekrümmt wird, weil dann zwangsläufig körniges Strahlmittel gegen einen Teilbereich der Innenwand des Düsenbereichs prallt und diesen abrasiv abträgt.Overall, the experts have recognized the advantages of relatively long narrowed areas, but there is still no practical implementation of this teaching. Rigid nozzle areas, in which a long constriction area is realized, are too bulky in practice. The previously proposed nozzle areas with a flexible constriction area always show a very high degree of wear when the nozzle area is curved in practical use, because granular abrasive then inevitably strikes a partial area of the inner wall of the nozzle area and removes it abrasively.

Ausgehend von dem zuvor erläuterten Stand der Technik liegt der Erfindung die Aufgabe zugrunde, ein praxisgerechtes Strahlgerät anzugeben, ein Strahlgerät also, bei dem die Vorteile eines langgestreckten Verengungsbereiches genutzt werden können, bei dem gleichzeitig eine praxis gerechte Handlung der Strahldüse möglich ist und bei dem schliesslich der Verschleiss möglichst gering gehalten wird.Starting from the prior art explained above, the invention has for its object to provide a practical blasting device, i.e. a blasting device in which the advantages of an elongated constriction area can be used, in which at the same time a practice-oriented action of the blasting nozzle is possible and finally the wear is kept as low as possible.

Das erfindungsgemässe Strahlgerät, bei dem die zuvor aufgezeigte Aufgabe gelöst ist, ist dadurch gekennzeichnet, dass die Rohrstücke durch ringförmige Zwischenräume voneinander getrennt und über Gelenkteile polygonzugartig miteinander verbunden sind und die Gelenkteile in radialer Richtung ausserhalb des gedachten Körpers in den Bereichen der ringförmigen Zwischenräume angeordnet sind.The blasting device according to the invention, in which the above-mentioned object is achieved, is there characterized in that the pipe sections are separated from one another by annular spaces and are connected to one another in the manner of a polygon by means of joint parts, and the joint parts are arranged in the radial direction outside the imaginary body in the regions of the annular spaces.

Bei dem erfindungsgemässen Strahlgerät ist die Strahldüse in dem aus einzelnen Rohrstücken zusammengesetzten Bereich, insbesondere den Verengungsbereich, biegbar, so dass diese Strahldüse mit einem langgestreckten Verengungsbereich erheblich besser handhabbar ist als die Strahldüse bei dem bekannten Strahlgerät, von dem die Erfindung ausgeht. Erfindungsgemäss findet eine Umlenkung des mit Strahlmittel beladenen Tragluftstromes praktisch nur im Bereich der Gelenkteile statt. Dazu sind die Gelenkteile selbst dadurch wirksam gegen Verschleiss geschützt, dass sie sich ausserhalb des eigentlichen Weges des mit Strahlmittel beladenen Tragluftstromes befinden. Lediglich die geraden Rohrstücke, insbesondere deren in Flugrichtung der Körner des Strahlmittels vorn liegende Enden müssen abriebfest ausgebildet sein. Die axiale Breite der ringförmigen Zwischenräume steht dabei mit der Wandstärke der Rohrstücke insoweit in einem Zusammenhang, als die durch die Breite der Zwischenräume vorgegebene maximal mögliche Biegung der Strahldüse nicht dazu führen darf, dass die Gelenkteile unmittelbar von Körnern des Strahlmittels erreicht werden können. Dies aber hängt mit der radialen Tiefe der Zwischenräume, also mit der Wandstärke der Rohrstücke zusammen.In the blasting device according to the invention, the blasting nozzle can be bent in the area composed of individual pipe pieces, in particular the constriction area, so that this blasting nozzle with an elongated constriction area is considerably easier to handle than the blasting nozzle in the known blasting device from which the invention is based. According to the invention, the air stream loaded with blasting agent is deflected practically only in the area of the joint parts. For this purpose, the joint parts themselves are effectively protected against wear by being outside the actual path of the air stream loaded with blasting media. Only the straight pipe sections, in particular their ends at the front in the direction of flight of the grains of the blasting medium, must be designed to be resistant to abrasion. The axial width of the annular gaps is related to the wall thickness of the pipe sections insofar as the maximum possible bend of the blasting nozzle given by the width of the gaps must not lead to the joint parts being able to be reached directly by grains of the blasting medium. But this is related to the radial depth of the gaps, that is, the wall thickness of the pipe sections.

Es ist zwar bereits ein Strahlgerät bekannt, bei dem die Strahldüse aus mehreren starren, geraden, miteinander verbundenen Rohrstücken zusammengesetzt ist, die Rohrstücke über Gelenkteile polygonzugartig miteinander verbunden sind und die Gelenkteile ausserhalb der Rohrstücke angeordnet sind (vgl. die DE-C 698 841). Es handelt sich hierbei jedoch um eine Strahldüse mit einem im wesentlichen gleichmässigen Innenquerschnitt, also nicht mit einem zu einer Düsenengstelle hin sich verjüngenden Verengungsbereich und einem sich an die Düsenengstelle anschliessenden Erweiterungsbereich. Wesentlich für dieses bekannte Strahlgerät ist, dass die einzelnen Rohrstücke unmittelbar aneinander zur Anlage kommen, so dass beim Biegen der Strahldüse der wirksame Querschnitt für die mit Strahlmittel beladene Tragluft jeweils stufenweise verengt wird. Dieses bekannte Strahlgerät hat folglich das erfindungsgemässe Strahlgerät, bei dem die Rohrstücke gewollt durch ringförmige Zwischenräume voneinander getrennt sind, nicht nahelegen können.A blasting device is already known in which the blasting nozzle is composed of a plurality of rigid, straight, interconnected pipe sections, the pipe sections are connected to one another in the manner of a polygon and the joint parts are arranged outside the pipe sections (cf. DE-C 698 841) . However, this is a jet nozzle with a substantially uniform internal cross-section, that is to say not with a narrowing region tapering towards a nozzle constriction and an expansion region adjoining the nozzle constriction. It is essential for this known blasting device that the individual pipe sections come into direct contact with one another, so that when the blasting nozzle is bent, the effective cross section for the carrying air loaded with blasting medium is narrowed in stages. This known blasting device has consequently not been able to suggest the blasting device according to the invention in which the pipe sections are deliberately separated from one another by annular spaces.

Im einzelnen gibt es verschiedene Möglichkeiten, das erfindungsgemässe Strahlgerät auszugestalten und weiterzubilden, was im folgenden nur beispielhaft erläutert werden soll.In particular, there are various options for designing and developing the blasting device according to the invention, which will only be explained below by way of example.

Eine besonders vorteilhafte Ausbildung des erfindungsgemässen Strahlgerätes ist dadurch gegeben, dass der Erweiterungsbereich die zweifache bis dreifache, vorzugsweise die zweieinhalbfache Länge des Verengungsbereiches aufweist. Mit derartigen Düsenbereichen werden Austrittsgeschwindigkeiten der Körner des Strahlmittels erzielt, die der Geschwindigkeit des Tragluftstromes weitgehend angenähert sind. Dennoch bleibt der Düsenbereich praktisch handhabbar, weil sowohl der Verengungsbereich als auch der Erweiterungsbereich Gelenkstellen aufweist und somit auch in räumlich beengten Verhältnissen gearbeitet werden kann.A particularly advantageous embodiment of the blasting device according to the invention is given in that the expansion area has twice to three times, preferably two and a half times the length of the constriction area. With such nozzle areas, exit velocities of the grains of the blasting agent are achieved which are largely approximated to the speed of the air flow. Nevertheless, the nozzle area remains practically manageable because both the constriction area and the expansion area have articulation points and can therefore also be used in spatially confined spaces.

Bei dem erfindungsgemässen Strahlgerät kann es sich empfehlen, zumindest ein Teilstück des Verengungsbereichs, das mit der Zuleitung verbunden ist, aus einem nachgiebigen Material herzustellen, beispielsweise einstückig mit der Zuleitung auszubilden. In diesem Teilstück ist die Geschwindigkeit der Körner des Strahlmittels noch so gering, dass die abrasive Wirkung vernachlässigtwerden kann. Die Vorzüge des polygonzugartig ausgebildeten Teilstücks des Düsenbereiches zeigen sich somit insbesondere in den Bereichen hoher Geschwindigkeit der Körner des Strahlmittels, also in der Nähe des Austrittsendes des Düsenbereiches. Zweckmässig sollte deshalb der an die Düsenengstelle angrenzende Teil des Verengungsbereiches und der gesamte Erweiterungsbereich aus polygonzugartigen Teilstückes aufgebautsein.In the blasting device according to the invention, it may be advisable to manufacture at least a portion of the constriction area that is connected to the feed line from a resilient material, for example to form it in one piece with the feed line. In this section, the speed of the grains of the abrasive is so low that the abrasive effect can be neglected. The advantages of the polygonal section of the nozzle area are thus particularly evident in the areas of high speed of the grains of the blasting medium, that is to say in the vicinity of the outlet end of the nozzle area. Therefore, the part of the constriction area adjacent to the nozzle constriction area and the entire extension area should be constructed from a polygonal section.

Für die Gelenkteile des erfindungsgemässen Strahlgerätes sind verschiedenartige Ausführungen möglich. Sie können als Kugelgelenke ausgebildet sein, wobei die einzelnen Kugeln jeweils einen inneren Durchlass für den mit dem Strahlmittel beladenen Tragluftstrom aufweisen. Weiterhin sind einfache Gelenke mit einer ortsfesten, quer zur Flugrichtung des Strahlmittels angeordneten Schwenkachse möglich, wobei es sich empfiehlt, aufeinanderfolgende Schwenkachsen um 90° zu versetzen, so dass auch eine Bewegung im Raum möglich ist. Schliesslich bieten sich elastische oder nachgiebige Muffen für die Verbindung zweier starrer Rohrstücke an. Diese müssen nicht aus einem Material gefertigt werden, das ausreichend abriebfest ist, da sie sich vollständig ausserhalb der Flugbahn des Strahlmittels befinden.Various designs are possible for the joint parts of the blasting device according to the invention. They can be designed as ball-and-socket joints, the individual balls each having an inner passage for the stream of carrier air loaded with the blasting agent. Simple joints with a fixed swivel axis arranged transversely to the direction of flight of the blasting medium are also possible, it being advisable to offset successive swivel axes by 90 ° so that movement in space is also possible. Finally, elastic or resilient sleeves are available for connecting two rigid pipe sections. These do not have to be made of a material that is sufficiently abrasion-resistant, since they are completely outside the trajectory of the blasting medium.

Drei Ausführungsbeispiele eines Düsenbereiches eines erfindungsgemässen Strahlgerätes werden im folgenden näher erläutert und unter Bezugnahme auf die Zeichnung beschrieben; es zeigt

  • Fig. 1 einen Längsschnitt durch ein erfindungsgemässes Strahlgerät mit einem Düsenbereich, der mit einem nachgiebigen Mantel überzogen ist,
  • Fig. 2 einen Längsschnitt durch ein erfindungsgemässes Strahlgerät mit einem Düsenbereich, dessen Gelenkteile jeweils durch einen Faltenbalg gebildet sind, und
  • Fig. 3 einen Längsschnitt durch zwei über ein als Kugelgelenk ausgebildetes Gelenkteil miteinander verbundene Rohrstücke eines erfindungsgemässen Strahlgerätes.
Three exemplary embodiments of a nozzle area of a blasting device according to the invention are explained in more detail below and described with reference to the drawing; it shows
  • 1 shows a longitudinal section through a blasting device according to the invention with a nozzle area which is covered with a flexible jacket,
  • 2 shows a longitudinal section through a blasting device according to the invention with a nozzle area, the joint parts of which are each formed by a bellows, and
  • 3 shows a longitudinal section through two pipe pieces of a blasting device according to the invention connected to one another via a joint part designed as a ball joint.

Bei dem in Fig. 1 gezeigten Strahlgerät ist eine Zuleitung 1 mit einem Düsenbereich 2 verbunden. Die Zuleitung 1 ist eingangsseitig an eine nicht dargestellte Quelle für ein Gemisch aus komprimierter Tragluft und einem Strahlmittel angeschlossen; sie ist aus einem nachgiebigen Material gefertigt und dadurch biegsam. Der Innenquerschnitt der Zuleitung 1 ist auf der gesamten Länge konstant und so ausgelegt, dass eine Flugförderung des Strahlmittels bei geringer Geschwindigkeit der Körner dieses Strahlmittels stattfindet. Ausgangsseitig ist die Zuleitung 1 an den Düsenbereich 2 angeschlossen, der sich aus einem langgestreckten Verengungsbereich 3 und einem diesen fortsetzenden Erweiterungsbereich 4 zusammensetzt. Zwischen beiden befindet sich eine Düsenengstelle 5, die Stelle geringsten Innenquerschnittes der gesamten Anordnung.In the blasting device shown in FIG. 1, a feed line 1 is connected to a nozzle area 2. The supply line 1 is connected on the input side to a source (not shown) for a mixture of compressed air and a blasting agent; it is made from a resilient material and is therefore flexible. The inner cross section of the feed line 1 is constant over the entire length and is designed in such a way that the blasting medium is promoted at low speed by the grains of this blasting medium. On the output side, the feed line 1 is connected to the nozzle area 2, which is composed of an elongated constriction area 3 and an extension area 4 that continues this. Between the two is a nozzle constriction 5, the point of the smallest internal cross section of the entire arrangement.

Der Düsenbereich 2 besteht aus insgesamt zehn einzelnen, starren und geraden Rohrstükken 6, 7 und 8, deren Innenwand so geformt und die so angeordnet sind, dass sie bei geradlinig gestrecktem Düsenbereich 2 einen gedachten sich gleichmässig verjüngenden und sich anschliessend wieder erweiternden Körper darstellen. In der konkreten Ausführung ist dieser Körper aus zwei Kegelstümpfen zusammengesetzt, die mit ihrer Kreisfläche kleineren Durchmessers - nämlich dem Durchmesser der Düsenengstelle 5 - aneinanderliegen. Dieser gedachte Körper beinhaltet die Flugbahnen der Körner des Strahlmittels.The nozzle area 2 consists of a total of ten individual, rigid and straight pipe pieces 6, 7 and 8, the inner wall of which is shaped and which are arranged in such a way that they represent an imaginary, uniformly tapering and subsequently expanding body when the nozzle area 2 is straight. In the specific embodiment, this body is composed of two truncated cones, which lie against one another with their circular area of smaller diameter - namely the diameter of the nozzle constriction 5. This imaginary body contains the trajectories of the grains of the abrasive.

Die einzelnen Rohrstücke 6, und 8 sind so hintereinander angeordnet, dass jeweils ein ringförmiger Zwischenraum 9 freibleibt. Die Länge des Zwischenraums 9 beträgt etwa 20% der Länge eines einzelnen Rohrstückes 6,7,8. Dadurch werden zwischen den starren Rohrstücken 6, 7, 8 Freiräume für eine Gelenkbewegung geschaffen. Die insgesamt zehn Rohrstücke 6, 7, 8 sind aussen mit einem Mantel 10 überzogen, der die relative Anordnung der einzelnen Rohrstücke 6, 7, 8 sichert. Im gezeigten Ausführungsbeispiel nach Fig. 1 geht der Mantel 10 einstückig in die Zuleitung 1 über. Damit hat das Material des Mantels 10 dieselben elastischen und nachgiebigen Eigenschaften wie die Zuleitung 1. Die ausserhalb der ringförmigen Zwischenräume 9 befindlichen Bereiche des Mantels 10 erlauben eine Gelenkbewegung zwischen benachbarten Rohrstücken 6, 7,8 und bilden somit die Gelenkteile 11. Der maximale Biegewinkel jedes derartigen Gelenkteiles 11 ist dadurch begrenzt, dass der ringförmige Zwischenraum 9 sich an einer Stelle schliesst, wenn benachbarte Rohrstücke 6, 7, aneinanderstossen. Um den Biegewinkel jedes einzelnen Gelenkteils 11 so gross wie möglich zu machen, sind die stirnseitigen Kanten gegenüberliegender Rohrstücke 6, 7, 8 so angeschrägt, dass der ringförmige Zwischenraum 9 sich V-förmig nach aussen erweitert. Dadurch kommen bei maximalem Biegewinkel zunächst die Kanten kleinen Durchmessers mit gegenüberliegenden Rohrstücken 6, 7, 8 in Kontakt. Die ringförmigen Zwischenräume 9 bilden zwar eine Diskontinuität und stören somit den Durchlauf des mit dem Strahlmittel beladenen Tragluftstroms, sie ermöglichen es jedoch, dass die Gelenkteile 11, die aus einem relativ preiswerten und wenig abriebfesten Material gebildet sind, in den Schattenbereichen des Tragluftstromes liegen und somit weitgehend vor der abrasiven Wirkung des Strahlmittels geschützt sind. Je nach Konfiguration des biegsamen Düsenbereiches 2 füllen sich die ringförmigen Zwischenräume 9 mehr oder weniger mit Körnern des Strahlmittels als Ablagerungen 12 an; diese Ablagerungen 12 des Strahlmittels schützen die Gelenkteile 11 des Mantels 10 gegen direkt auftreffende, schnellfliegende Körnchen des Strahlmittels.The individual pipe sections 6 and 8 are arranged one behind the other in such a way that an annular space 9 remains free. The length of the space 9 is about 20% of the length of a single piece of pipe 6,7,8. This creates free spaces for articulated movement between the rigid pipe sections 6, 7, 8. The total of ten pipe sections 6, 7, 8 are coated on the outside with a jacket 10, which ensures the relative arrangement of the individual pipe sections 6, 7, 8. In the exemplary embodiment shown in FIG. 1, the jacket 10 merges in one piece into the feed line 1. Thus, the material of the jacket 10 has the same elastic and resilient properties as the feed line 1. The areas of the jacket 10 located outside the annular spaces 9 allow articulation between adjacent pipe sections 6, 7, 8 and thus form the articulated parts 11. The maximum bending angle of each Such a joint part 11 is limited in that the annular space 9 closes at one point when adjacent pipe sections 6, 7 abut one another. In order to make the bending angle of each individual joint part 11 as large as possible, the end edges of opposite pipe sections 6, 7, 8 are chamfered in such a way that the annular space 9 widens outward in a V-shape. As a result, the edges of small diameter initially come into contact with opposite pipe sections 6, 7, 8 at the maximum bending angle. The annular spaces 9 form a discontinuity and thus interfere with the passage of the air stream loaded with the abrasive, but they enable the joint parts 11, which are formed from a relatively inexpensive and less abrasion-resistant material, to lie in the shadow areas of the air stream and thus are largely protected from the abrasive effect of the abrasive. Depending on the configuration of the flexible nozzle area 2, the annular spaces 9 fill more or less with grains of the blasting agent as deposits 12; these deposits 12 of the blasting agent protect the joint parts 11 of the jacket 10 against directly impacting, fast-flying granules of the blasting agent.

Wie Fig. 1 zeigt, sind die Rohrstücke 6 des Verengungsbereiches 3 als in Flugrichtung - (Pfeil 13) - konvergierende Kegelmantelringe ausgebildet. Ebenso sind auch die Rohrstücke 8 des Erweitungsbereiches 4 Kegelmantelringe.As shown in FIG. 1, the tube pieces 6 of the constriction area 3 are designed as conical jacket rings converging in the direction of flight (arrow 13). Likewise, the pipe sections 8 of the expansion area 4 are conical casing rings.

Das Rohrstück 7, in dem die Düsenengstelle 5 ausgebildet ist, ist sowohl ein Teil des Verengungsbereiches 3 als auch ein Teil des Erweiterungsbereiches 4 und besteht dementsprechend aus einem sich konisch verengenden Kegelmantelring und einem sich konisch erweiternden Kegelmantelring. Die Rohrstücke 6, 7, 8 sind aus einem sehr abriebfesten Material gefertigt.The pipe section 7, in which the nozzle constriction 5 is formed, is both a part of the constriction area 3 and a part of the expansion area 4 and accordingly consists of a conically narrowing conical jacket ring and a conically expanding conical jacket ring. The pipe sections 6, 7, 8 are made of a very abrasion-resistant material.

Der Mantel 10 ist in geeigneter Weise mit den Aussenwänden der Rohrstücke 6, 7, verbunden; er ist beispielsweise aufgeschrumpft. Zur mechanischen Aussteifung des Mantels 10, insbesondere seiner Gelenkteile 11 kann es sich empfehlen, zwischen den einzelnen Rohrstücken 6, 7, 8 jeweils kurze Schraubenfedern anzuordnen, die die aneinandergrenzenden Rohrstücke 6, 7, 8 auseinanderdrücken und dadurch den gesamten Düsenbereich 2 stets in seine geradlinige Form drücken.The jacket 10 is connected in a suitable manner to the outer walls of the pipe sections 6, 7; for example, it has shrunk. For the mechanical stiffening of the jacket 10, in particular its hinge parts 11, it may be advisable to arrange short coil springs between the individual pipe sections 6, 7, 8, which push the adjacent pipe sections 6, 7, 8 apart and thereby always keep the entire nozzle area 2 in its straight line Press shape.

Wie im Ausführungsbeispiel nach Fig. 1 ist auch im Ausführungsbeispiel nach Fig. 2 die Zuleitung 1 auf das in Flugrichtung - (Pfeil 13) - der Körner des Strahlmittels gesehen erste Rohrstück 6 aufgeschrumpft, so dass der Übergangsbereich zwischen der Zuleitung 1 und dem Düsenbereich 2 möglichst glatt ist und den Tragluftstrom somit praktisch nicht beeinflusst. Die einzelnen Rohrstücke 6 des Düsenbereiches 2 nach Fig. 2, der lediglich einen Verengungsbereich 3 aufweist, sind über als Faltenbälge ausgebildete Gelenkteile 14 miteinander verbunden. Die insbesondere als metallische Faltenbälge ausgebildeten Gelenkteile 14 haben eine gewisse Federcharakteristik, so dass sich in Ruhelage des Düsenbereichs 2 die gezeigte, geradlinige Form einstellt. Innenseitig sind die Eintrittsenden 15 der Rohrstücke 6 abgerundet, so dass bei einer Biegung der Gelenkteile 14 keine scharfen Kanten dem Tragluftstrom gegenüberstehen.As in the exemplary embodiment according to FIG. 1, in the exemplary embodiment according to FIG. 2, the feed line 1 is shrunk onto the first pipe section 6, as seen in the direction of flight - (arrow 13) - of the grains of the blasting medium, so that the transition area between the feed line 1 and the nozzle area 2 is as smooth as possible and therefore practically does not affect the air flow. The individual pipe sections 6 of the nozzle area 2 according to FIG. 2, which has only one constriction area 3, are connected to one another via joint parts 14 designed as bellows. The joint parts 14, which are designed in particular as metallic bellows, have a certain spring characteristic, so that the straight shape shown is obtained when the nozzle region 2 is in the rest position. The inlet ends 15 of the pipe sections 6 are rounded on the inside, so that when the joint parts 14 bend, there are no sharp edges opposite the air flow.

In den Ausführungsbeispielen nach Fig. 1 und 2 befinden sich die Gelenkteile 11 und 14 jeweils ausserhalb des eigentlichen Wegs der fliegenden Strahlmittelkörner. Dadurch ist bei der Wahl des Materials für die Gelenkteile 11, 14 lediglich die Elastizität bzw. Nachgiebigkeit, nicht aber die Abriebfestigkeit ausschlaggebend. Vielmehr ist es als besonderer Vorteil dieser beiden Ausführungsbeispiele anzusehen, dass beide mechanischen Funktionen - Biegsamkeit und Abriebfestigkeit - voneinander getrennt sind. Im Gegensatz hierzu kommt das Gelenkteil 16 im Ausführungsbeispiel nach Fig. 3 unmittelbar mit dem beschleunigten Strahlmittel in Berührung und ist deshalb zumindest im Bereich dieser Berührungsstellen aus einem abriebfesten Material zu fertigen. Das Gelenkteil 16 ist als Kugelgelenk ausgebildet und setzt sich aus einem Kugelkörper 17 mit einem inneren Durchlass 18, aus Kugelschalen 19 an den angrenzenden Rohrstücken 6 und aus einer Kapsel 20 zusammen. Der Kugelkörper 17 bildet das innerste Teil dieser Anordnung, sein innerer Durchlass 18 verengt sich zur Kugelmitte hin etwa diaboloförmig und hat zwei Öffnungen 21. Auf der Aussenfläche des Kugelkörpers 17 gelten die Innenflächen der Kugelschalen 19, die zentrisch in Rohrstücke übergehen, wobei jeweils eine Mündung 22 freibleibt. Der Durchmesser der Mündungen 22 ist - wie noch erläutert wird - so mit dem maximalen Schwenkwinkel jedes einzelnen Rohrstücks 6 und dem Durchmesser der Öffnung 21 abgestimmt, dass sich die Mündung 22 nie ausserhalb der Öffnung 21 befinden kann. Das rechte Rohrstück 6 in Fig. 3 ist weitestmöglich nach unten ausgelenkt, das linke Rohrstück 6 befindet sich in seiner Mittelstellung. Eine Winkelbegrenzung wird dadurch erreicht, dass die stirnseitigen Aussenflächen der Kugelschale 19 gegen einen Aufschlag 23 der Kapsel 20 stossen. Die Kapsel 20 schliesslich hat Haltebereiche 24, die die Kugelschalen 19 gegen den Kugelkörper 17 drücken und dadurch das Gelenkteil 16 zusammenhalten.In the exemplary embodiments according to FIGS. 1 and 2, the joint parts 11 and 14 are each located outside the actual path of the flying abrasive grains. This is when choosing the Material for the joint parts 11, 14 only the elasticity or resilience, but not the abrasion resistance is decisive. Rather, it is to be regarded as a particular advantage of these two exemplary embodiments that the two mechanical functions - flexibility and abrasion resistance - are separated from one another. In contrast to this, the joint part 16 in the exemplary embodiment according to FIG. 3 comes into direct contact with the accelerated abrasive and must therefore be made of an abrasion-resistant material at least in the area of these contact points. The joint part 16 is designed as a ball joint and is composed of a spherical body 17 with an inner passage 18, of spherical shells 19 on the adjacent tube pieces 6 and of a capsule 20. The spherical body 17 forms the innermost part of this arrangement, its inner passage 18 narrows towards the center of the ball approximately diabolically and has two openings 21. On the outer surface of the spherical body 17, the inner surfaces of the spherical shells 19 apply, which merge centrally into tubular pieces, each with an opening 22 remains free. The diameter of the mouths 22 is - as will be explained later - so matched with the maximum swivel angle of each individual pipe section 6 and the diameter of the opening 21 that the mouth 22 can never be outside the opening 21. The right pipe section 6 in FIG. 3 is deflected as far down as possible, the left pipe section 6 is in its central position. An angle limitation is achieved in that the front outer surfaces of the spherical shell 19 abut against an impact 23 of the capsule 20. Finally, the capsule 20 has holding areas 24 which press the spherical shells 19 against the spherical body 17 and thereby hold the joint part 16 together.

Die Gesamtlänge des Verengungsbereiches 3 eines erfindungsgemässen Strahlgerätes liegt bei etwa 50 bis 100 cm. Zusammen mit einem erfindungsgemässen etwa zweieinhalbfach längeren Erweiterungsbereich 4 hat der gesamte Düsenbereich 2 somit eine erhebliche Länge von etwa 1,75 m bis 3,50 m. Derartig lange Düsenbereiche 2 lassen sich jedoch handhaben, wenn sie, wie hier vorgeschlagen, polygonzugartig ausgebildet sind.The total length of the constriction area 3 of a blasting device according to the invention is approximately 50 to 100 cm. Together with an expansion area 4 according to the invention, which is approximately two and a half times longer, the entire nozzle area 2 thus has a considerable length of approximately 1.75 m to 3.50 m. Such long nozzle areas 2 can, however, be handled if, as proposed here, they are designed in the manner of a polygon.

Claims (8)

1. A jet appliance, particularly for compressed air blasting, with a hose-like delivery pipe (1) of substantially constant internal cross-section that can be attached at its entry end to a source of a mixture of compressed transporting air and blasting medium and can be attached at its exit end to a blasting nozzle (2) which possesses an elongated constriction portion (3) narrowing down from the internal cross-section of the delivery pipe (1) to a jet restriction (5) and if required an expansion portion (4) attached to the jet restriction (5) and is at least partially assembled from several rigid and preferably straight tubular pieces (6, 7, 8) joined to one another and in which the interiors of the tubular pieces (6, 7, 8) represent an imaginary body, narrowing or expanding as the case may be, characterized in that the tubular pieces (6, 7, 8) are separated from one another by ring-shaped interspaces (9) and are connected together like the sides of a polygon by flexible couplings (11, 14, 16) that are located externally to the imaginary body in a radial direction in the areas of the ring-shaped interspaces (9).
2. A jet appliance according to Claim 1, characterized in that the length of the expansion portion (4) is twice to three times, preferably two and a half times, the length of the constriction portion (3).
3. A jet appliance according to Claim 1 or 2, characterized in that the expansion portion (4) is constructed to be essentially uniformly diverging, and particularly conically diverging.
4. A jet appliance according to one of Claims 1 to 3, characterized in that the inner surfaces of the flexible couplings (16) are located in the region of the lines of flight of the grains of blasting medium, and at least the inner surfaces of the flexible couplings (16) consist of abrasion-resistant material.
5. A jet appliance according to Claim 4, characterized in that each flexible coupling (16) possesses a spherical body (17) with an internal passage (18) and spherical shells (19) attached to the adjacent tubular pieces (6), and in the straightened-out position of the discharge nozzle (2) the internal passage (18) of the spherical body (17) is in alignment with orifices (22) in the spherical shells (19).
6. A jet appliance according to Claim 5, characterized in that the diameter of the opening (21) of the internal passage (18) of the spherical body (17) is equal to the sum of the diameter of the orifice (22) in the spherical shells (19) and the length of the bottom of the spherical shell in contact with the spherical body (17) when a tubular piece (6) is deflected to its maximum angular deflection.
7. A jet appliance according to one of Claims 1 to 6, characterized in that the flexible couplings (11, 14, 16) possess a device to limit their angular movement, particularly a stop (23).
8. A jet appliance according to one of Claims 1 to 7, characterized in that the inlet ends of tubular pieces (6, 7, 8) situated at the front in the direction of line of flight of the grains of the blasting medium are formed of particularly abrasion-resistant material.
EP82106144A 1981-07-09 1982-07-09 Blasting apparatus, in particular for abrasive blasting by compressed air Expired EP0070002B1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT82106144T ATE16083T1 (en) 1981-07-09 1982-07-09 BLASTING DEVICE, ESPECIALLY FOR COMPRESSED AIR BLASTING.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE19813127074 DE3127074A1 (en) 1981-07-09 1981-07-09 BLASTING DEVICE, ESPECIALLY FOR AIR BLASTING
DE3127074 1982-07-09

Publications (2)

Publication Number Publication Date
EP0070002A1 EP0070002A1 (en) 1983-01-19
EP0070002B1 true EP0070002B1 (en) 1985-10-16

Family

ID=6136470

Family Applications (1)

Application Number Title Priority Date Filing Date
EP82106144A Expired EP0070002B1 (en) 1981-07-09 1982-07-09 Blasting apparatus, in particular for abrasive blasting by compressed air

Country Status (3)

Country Link
EP (1) EP0070002B1 (en)
AT (1) ATE16083T1 (en)
DE (2) DE3127074A1 (en)

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CA1272662A (en) * 1985-03-26 1990-08-14 Canon Kabushiki Kaisha Apparatus and process for controlling flow of fine particles
FR2579487B1 (en) * 1985-03-26 1989-05-12 Canon Kk APPARATUS FOR CONTROLLING THE FLOW OF FINE PARTICLES
US6851627B2 (en) * 2001-07-31 2005-02-08 Flow International Corporation Multiple segment high pressure fluidjet nozzle and method of making the nozzle
DE202018002678U1 (en) * 2018-01-24 2018-09-06 Karlsruher Institut für Technologie two-fluid nozzle

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CH131161A (en) * 1927-02-24 1929-01-31 Rhein Ruhr Maschinenvertrieb D Nozzle for sandblasting blower.
DE698841C (en) * 1939-01-01 1940-11-18 Fritz Seibel Jet nozzle equipped with hard lining and consisting of ring parts
US2583726A (en) * 1948-01-26 1952-01-29 Chalom Joseph Aaron Nozzle
GB722464A (en) * 1952-08-11 1955-01-26 William Howard Mead Abrasive blasting nozzle
DE2052156A1 (en) * 1970-10-23 1972-04-27
DE2843013A1 (en) * 1978-10-03 1980-04-10 Peiniger Ernst Gmbh Sand blasting hose with nozzle - has long gradually reducing cross=section leading to nozzle end

Also Published As

Publication number Publication date
ATE16083T1 (en) 1985-11-15
EP0070002A1 (en) 1983-01-19
DE3127074A1 (en) 1983-01-27
DE3266927D1 (en) 1985-11-21

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