EP0261376B1 - Device for accelerating magnetic blasting materials - Google Patents

Device for accelerating magnetic blasting materials Download PDF

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Publication number
EP0261376B1
EP0261376B1 EP87111743A EP87111743A EP0261376B1 EP 0261376 B1 EP0261376 B1 EP 0261376B1 EP 87111743 A EP87111743 A EP 87111743A EP 87111743 A EP87111743 A EP 87111743A EP 0261376 B1 EP0261376 B1 EP 0261376B1
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EP
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Prior art keywords
coil
concentrator
accelerating
blasting
blasting abrasive
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EP87111743A
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German (de)
French (fr)
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EP0261376A2 (en
EP0261376A3 (en
Inventor
Gerd Prof. Dr.-Ing. Stange
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ALFRED GUTMANN GESELLSCHAFT FUER MASCHINENBAU MBH
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Alfred Gutmann Gesellschaft fur Maschinenbau Mbh
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F41—WEAPONS
    • F41B—WEAPONS FOR PROJECTING MISSILES WITHOUT USE OF EXPLOSIVE OR COMBUSTIBLE PROPELLANT CHARGE; WEAPONS NOT OTHERWISE PROVIDED FOR
    • F41B6/00—Electromagnetic launchers ; Plasma-actuated launchers
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B24—GRINDING; POLISHING
    • B24C—ABRASIVE OR RELATED BLASTING WITH PARTICULATE MATERIAL
    • B24C5/00—Devices or accessories for generating abrasive blasts
    • B24C5/08—Devices for generating abrasive blasts non-mechanically, e.g. of metallic abrasives by means of a magnetic field or by detonating cords

Definitions

  • the invention relates to a device for accelerating a blasting medium consisting of particles which can be influenced magnetically, in particular iron particles, for treating workpiece surfaces with one or more electromagnetic accelerator coils (s) arranged along the path of the blasting medium which excite or excite depending on the moving blasting medium will.
  • a device for accelerating a blasting medium consisting of particles which can be influenced magnetically, in particular iron particles, for treating workpiece surfaces with one or more electromagnetic accelerator coils (s) arranged along the path of the blasting medium which excite or excite depending on the moving blasting medium will.
  • the invention is based on the object of creating a device of the type mentioned at the outset, i.e. to create a device in which the blasting medium is accelerated with the aid of the magnetic force generated in an accelerator coil and thereby manages with a lower energy requirement compared to conventional types of acceleration with equivalent performance (throughput quantity of blasting medium per unit time).
  • Flow concentrators of this type have hitherto been used in completely different fields, in particular in basic research. These flux concentrators have a core made of electrically highly conductive material, e.g. made of copper, in which there is a usable field bore and a radial slot. If a winding which is located on the outside of the core is now flowed through by a pulsed current, then a current is induced in the opposite direction into the electrically well-conducting core according to the transformer principle and flows as a pulse current only on the surface of the core. At the location of the radial slot, the current flow is forced inwards around the useful field bore.
  • electrically highly conductive material e.g. made of copper
  • abrasive device which is basically constructed in the same way as conventional abrasive devices. It consists of an electromagnetic acceleration unit 1, the heart of which is a flux concentrator. A movable blasting hose 3 is arranged in the blasting agent cabin 2, by means of which an operator can direct the accelerated blasting agent onto a workpiece 4. The blasting agent return and feed is designated by 5.
  • the acceleration unit shown in Fig. 2 consists of a flux concentrator 6 as an accelerator coil.
  • the blasting agent 9 is fed via a feed device 8.
  • a metering coil 7 serves as a “pre-bundler” through which the abrasive is distributed in the desired amount to the flux concentrator 6.
  • the blasting agent outlet is designated by 10.
  • On this Exit is the jet hose 3 recognizable in Fig. 1 placed.
  • the essentially rotationally symmetrical flow concentrator shown in FIG. 4 practically as a section perpendicular to the axis of the movement of the blasting medium has a core 11 constructed from a material which is a good electrical conductor (e.g. copper) and in which a cylindrical useful field bore 12 and a radial slot 13 are provided.
  • the excitation winding which can consist of several turns, is designated by 14.
  • FIG. 5 and 6 another advantageous embodiment is shown.
  • two excitation windings 14 and 15 are nested concentrically with corresponding concentrator cores.
  • the inner part corresponds to that according to FIG. 4 and is designated with corresponding reference numerals.
  • a concentrator shell 18 is placed on this inner part, which acts as an additional core for the outer field winding 15. The two arrangements add up in their effect.
  • the concentrator shell 18 is connected to the inner core 11 at 19.
  • FIG. 7 shows the circuit diagram of a pulse generator working with thyristors Ti, T 2 , with which a system constructed according to FIGS. 5 and 6 was tested.
  • the voltage source with the voltage UO charges the capacitor C L , which is periodically discharged via the thyristors Ti, T 2 acting in parallel as controllable switches into the load inductance L L of the flux concentrator (inductance of the excitation coils) and, due to the pulse-shaped current flow thus created, the desired one there Effective field with induction B.
  • FIG. 8 shows a curve of the induction B over the axis of the flux concentrator obtained with a concentrator construction according to FIGS. 5 and 6 and a pulse generator according to FIG. 7.
  • the dimensions given in millimeters correspond to an embodiment that has been tried and tested in practice.
  • two excitation windings with ten windings each with a current of 10,000 A were operated.
  • the turns of the excitation windings were directly water-cooled.
  • the power loss is approx. 5 kW.
  • the accelerator unit shown in Fig. 2 works so that the metering coil 7 is briefly de-energized (see also the upper timing diagram in Fig. 3), so that the induction B of this metering coil also disappears. The abrasive is released and starts to move. If the magnetic flux concentrator 6 acting as an accelerator is excited at the same time (see also the lower time diagram in FIG. 3), a strong acceleration of the blasting agent will start under the influence of the much higher induction B of the flux concentrator. This is only effective during the pulse duration in the accelerator coil. This pulse duration must be set so that the pulse ends when the blasting agent emerges from the flow concentrator.
  • a measuring coil can be used, which is arranged between the coils 6 and 7 in the embodiment according to FIG. 2.
  • This measuring coil detects incoming blasting media as an electrical signal in order to ignite a current pulse in the accelerator coil following in the direction of movement (designated 6 in FIG. 2). This enables particularly economical and precise control.

Description

Die Erfindung betrifft eine Vorrichtung zum Beschleunigen eines aus magnetisch beeinflussbaren Partikeln, insbesondere Eisenpartikeln, bestehenden Strahlmittels zum Behandeln von Werkstückoberflächen mit einer oder mehreren längs des Weges des Strahlmittels angeordneten elektromagnetischen Beschleunigerspule(n), die in Abhängigkeit von dem sich bewegenden Strahlmittel er-oder entregt werden.The invention relates to a device for accelerating a blasting medium consisting of particles which can be influenced magnetically, in particular iron particles, for treating workpiece surfaces with one or more electromagnetic accelerator coils (s) arranged along the path of the blasting medium which excite or excite depending on the moving blasting medium will.

Herkömmliche Vorrichtungen arbeiten mit mechanischen Schleuderrädern oder mit Hilfe von Preßluft, um das Strahlmittel zu beschleunigen. Es ist auch schon versucht worden, diese Beschleunigungsverfahren durch den Einsatz von Beschleunigerspulen zu ersetzen, die die Beschleunigung mit Hilfe von Magnetkräften durchführen. In Verbindung mit den hintereinander geschalteten Beschleunigerspulen ist es vorgeschlagen worden, zur Steuerung der Erregung der Beschleunigerspulen Photozellen einzusetzen, die in Abhängigkeit vom Durchschreiten des in dem Spulenfeld sich bewegenden Strahlmittels, die hintereinandergeschalteten Beschleunigerspulen steuern (CH-A-240 861).Conventional devices work with mechanical centrifugal wheels or with the aid of compressed air to accelerate the blasting medium. Attempts have also been made to replace these acceleration methods with the use of accelerator coils which carry out the acceleration using magnetic forces. In connection with the series-connected accelerator coils, it has been proposed to use photocells to control the excitation of the accelerator coils, which control the series-connected accelerator coils as a function of the passage of the blasting agent moving in the coil field (CH-A-240 861).

Wenn beispielsweise Preßluft als Treibmittel eingesetzt wird, so entsteht eine leicht zu handhabende Vorrichtung, die aber einen großen Energieaufwand erfordert, um die erforderliche Beschleunigung des Strahlmittels durchzuführen.If, for example, compressed air is used as the blowing agent, an easy-to-use device is created, which, however, requires a large amount of energy in order to carry out the required acceleration of the blasting agent.

Andere bekannte Linearbeschleuniger (DE-A-33 24 710) nutzen ebenfalls Beschleunigerspulen konventioneller Bauart, die in Richtung der Beschleuniger räumlich und zeitlich nacheinander wirken. Bei diesen Systemen ist eine sehr große Anzahl (12 bis 15 Stück) von Beschleunigerspulen notwendig, um auf die erforderliche Gesamtbeschleunigung zu kommen, wie sie zum Erreichen von Strahlmittelgeschwindigkeiten von 90 - 100 m/s benötigt werden. Eine derartige Geschwindigkeit ist für eine entsprechende Oberflächenbehandlung erforderlich. Solche mehrstufigen Anordnungen werfen erhebliche Probleme auf, da die zeitliche Abfolge der Pulse in den einzelnen Stufen sehr genau an die von Stufe zu Stufe zu nehmende Geschwindigkeit der Strahlmittelpakete angepaßt werden muß. Der Zwang zu mehrstufigen Anordnungen bei Verwendung konventioneller Beschleunigerspulen ist letzten Endes begründet in den geringen Induktionswerten, die mit solchen Spulen erzielbar sind.Other known linear accelerators (DE-A-33 24 710) also use conventional type accelerator coils, which act spatially and temporally one after the other in the direction of the accelerators. In these systems, a very large number (12 to 15 pieces) of accelerator coils is necessary in order to achieve the required total acceleration, as is required to achieve blasting media speeds of 90 - 100 m / s. Such a speed is required for an appropriate surface treatment. Such multi-stage arrangements pose considerable problems since the chronological sequence of the pulses in the individual stages has to be adapted very precisely to the speed of the blasting agent packets to be increased from stage to stage. The necessity for multi-stage arrangements when using conventional accelerator coils is ultimately due to the low induction values that can be achieved with such coils.

Der Erfindung liegt nun die Aufgabe zugrunde, eine Vorrichtung der eingangs genannten Art zu schaffen, d.h. eine Vorrichtung zu schaffen, bei der das Strahlmittel mit Hilfe der in einer Beschleunigerspule erzeugten Magnetkraft beschleunigt wird und dabei mit einem geringeren Energiebedarf im Vergleich zu herkömmlichen Beschleunigungsarten bei gleichwertiger Leistung (durchgesetzte Strahlmittelmenge pro Zeiteinheit) auskommt.The invention is based on the object of creating a device of the type mentioned at the outset, i.e. to create a device in which the blasting medium is accelerated with the aid of the magnetic force generated in an accelerator coil and thereby manages with a lower energy requirement compared to conventional types of acceleration with equivalent performance (throughput quantity of blasting medium per unit time).

Diese Aufgabe wird durch den Einsatz eines an sich bekannten Flußkonzentrators erreicht. Derartige Flußkonzentratoren wurden bisher auf vollständig anderen Gebieten, insbesondere in der Grundlagenforschung, eingesetzt. Diese Flußkonzentratoren weisen einen Kern aus elektrisch gutleitendem Material, z.B. aus Kupfer, auf, in dem eine Nutzfeldbohrung und ein radialer Schlitz vorhanden ist. Wenn nun eine sich außen auf dem Kern befindliche Wicklung von einem pulsförmigen Strom durchflossen wird, so wird nach dem Transformatorprinzip ein Strom in Gegenrichtung in den elektrisch gut leitenden Kern induziert, der als Pulsstrom nur an der Oberfläche des Kerns fließt. An der Stelle des radialen Schlitzes wird der Stromfluß nach innen um die Nutzfeldbohrung erzwungen. Hierdurch baut sich ein sehr starkes Magnetfeld auf, das so stark ist, daß in manchen Fällen bereits ein "einstufiger" Flußkonzentrator ausreicht, um die gewünschte Strahlmittelgeschwindigkeit zu erreichen. In jedem Fall ist aber gegenüber bekannten Anordnungen mit konventionellen Beschleunigerspulen eine Reduktion der Spulenzahl um den Faktor 4 - 5 möglich.This object is achieved by using a flow concentrator known per se. Flow concentrators of this type have hitherto been used in completely different fields, in particular in basic research. These flux concentrators have a core made of electrically highly conductive material, e.g. made of copper, in which there is a usable field bore and a radial slot. If a winding which is located on the outside of the core is now flowed through by a pulsed current, then a current is induced in the opposite direction into the electrically well-conducting core according to the transformer principle and flows as a pulse current only on the surface of the core. At the location of the radial slot, the current flow is forced inwards around the useful field bore. This creates a very strong magnetic field, which is so strong that in some cases a "single-stage" flux concentrator is sufficient to achieve the desired blasting medium speed. In any case, compared to known arrangements with conventional accelerator coils, the number of coils can be reduced by a factor of 4-5.

Vorteilhafte Ausgestaltungen sind Gegenstand der Ansprüche 2 und 3.Advantageous embodiments are the subject of claims 2 and 3.

Im folgenden wird die Erfindung unter Hinweis auf die Zeichnung anhand von Ausführungsbeispielen näher erläutert.The invention is explained in more detail below with reference to the drawing using exemplary embodiments.

Es zeigt:

  • Fig. 1 eine schematische perspektivische Ansicht einer Vorrichtung nach der Erfindung;
  • Fig. 2 einen schematischen Längsschnitt durch die eigentliche Beschleunigungseinheit mit einem Flußkonzentrator;
  • Fig. 3 ein Schaubild zur Veranschaulichung der zeitlichen Steuerung der wesentlichen Bauteile der Beschleunigereinheit nach Fig. 2;
  • Fig. 4 eine schematische Ansicht eines Flußkonzentrators im Querschnitt zur Verdeutlichung seiner Wirkungsweise;
  • Fig. 5 eine Stirnansicht auf eine Ausführungsform eines Flußkonzentrators;
  • Fig. 6 einen Schnitt gemäß der Linie VI-VI der Fig. 5;
  • Fig. 7 ein Ersatzschaubild für einen Pulsgenerator zur Versorgung eines Flußkonzentrators nach den Fig. 5 und 6; und
  • Fig. 8 ein Schaubild zur Verdeutlichung des Verlaufs der Induktion bei dem Flußkonzentrator nach Fig. 6.
It shows:
  • Figure 1 is a schematic perspective view of a device according to the invention.
  • 2 shows a schematic longitudinal section through the actual acceleration unit with a flux concentrator;
  • 3 shows a diagram to illustrate the timing of the essential components of the accelerator unit according to FIG. 2;
  • 4 shows a schematic view of a flow concentrator in cross section to illustrate its mode of operation;
  • 5 shows an end view of an embodiment of a flow concentrator;
  • Fig. 6 is a section along the line VI-VI of Fig. 5;
  • 7 shows an equivalent diagram for a pulse generator for supplying a flux concentrator according to FIGS. 5 and 6; and
  • 8 is a diagram to illustrate the course of the induction in the flux concentrator according to FIG. 6.

In Fig. 1 ist eine Strahlmittelvorrichtung dargestellt, die grundsätzlich so aufgebaut ist, wie herkömmliche Strahlmittelvorrichtungen. Sie besteht aus einer elektromagnetischen Beschleunigungseinheit 1, deren Herzstück ein Flußkonzentrator ist. In der Strahlmittelkabine 2 ist ein beweglicher Strahlschlauch 3 angeordnet, mit dessen Hilfe eine Bedienungsperson das beschleunigte Strahlmittel auf ein Werkstück 4 lenken kann. Die Strahlmittelrück-und zuführung ist mit 5 bezeichnet.1 shows an abrasive device which is basically constructed in the same way as conventional abrasive devices. It consists of an electromagnetic acceleration unit 1, the heart of which is a flux concentrator. A movable blasting hose 3 is arranged in the blasting agent cabin 2, by means of which an operator can direct the accelerated blasting agent onto a workpiece 4. The blasting agent return and feed is designated by 5.

Die in Fig. 2 dargestellte Beschleunigungseinheit besteht aus einem Flußkonzentrator 6 als Beschleunigerspule. Das Strahlmittel 9 wird über eine Zuführeinrichtung 8 zugeführt.The acceleration unit shown in Fig. 2 consists of a flux concentrator 6 as an accelerator coil. The blasting agent 9 is fed via a feed device 8.

Eine Dosierspule 7 dient als "Vorbündeler", durch den das Strahlmittel in der gewünschten Menge dem Flußkonzentrator 6 zugeteilt wird. Der Strahlmittelaustritt ist mit 10 bezeichnet. Auf diesen Austritt wird der in Fig. 1 erkennbare Strahlschlauch 3 aufgesetzt. Durch den Einsatz eines derartigen magnetischen Flußkonzentrators als Beschleunigerspule sind sehr viel höhere Induktionswerte (mindestens um den Faktor 4 bis 5 gegenüber konventionellen Beschleunigerspulen) erzielbar. Damit können bereits grundsätzlich in einer einstufigen Anordnung, wie sie in Fig. 2 dargestellt ist, Strahlmittelgeschwindigkeiten von ca. 50 bis 60 m/s erreicht werden. Die zeitliche Steuerung ist dadurch erheblich einfacher, weil der Flußkonzentrator 6 und die Dosierspule 7 zeitlich synchron so er- bzw. entregt werden können, wie es in Verbindung mit Fig. 3 dargestellt ist. Die geschwindigkeitsabhängige - und damit besonders komplexe - Steuerung weiterer Beschleunigungsstufen entfällt.A metering coil 7 serves as a “pre-bundler” through which the abrasive is distributed in the desired amount to the flux concentrator 6. The blasting agent outlet is designated by 10. On this Exit is the jet hose 3 recognizable in Fig. 1 placed. By using such a magnetic flux concentrator as an accelerator coil, much higher induction values (at least a factor of 4 to 5 compared to conventional accelerator coils) can be achieved. In principle, abrasive speeds of approximately 50 to 60 m / s can thus already be achieved in a one-stage arrangement, as shown in FIG. 2. The timing is considerably easier because the flux concentrator 6 and the metering coil 7 can be excited or de-energized synchronously, as shown in connection with FIG. 3. The speed-dependent - and thus particularly complex - control of further acceleration levels is eliminated.

Der in Fig. 4 praktisch als Schnitt senkrecht zur Achse der Bewegungdes Strahlmittels dargestellte, im wesentlichen rotationssymmetrische Flußkonzentrator weist einen aus elektrisch gut leitendem Material (z.B. Kupfer) aufgebauten Kern 11 auf, in dem eine zylindrische Nutzfeldbohrung 12 und ein radialer Schlitz 13 vorhanden sind. Die Erregerwicklung, die aus mehreren Windungen bestehen kann, ist mit 14 bezeichnet.The essentially rotationally symmetrical flow concentrator shown in FIG. 4 practically as a section perpendicular to the axis of the movement of the blasting medium has a core 11 constructed from a material which is a good electrical conductor (e.g. copper) and in which a cylindrical useful field bore 12 and a radial slot 13 are provided. The excitation winding, which can consist of several turns, is designated by 14.

In den Fig. 5 und 6 ist eine andere, vorteilhafte Ausführungsform dargestellt. Bei dieser Ausführungsform sind zwei Erregerwicklungen 14 und 15 konzentrisch mit entsprechenden Konzentratorkernen miteinander verschachtelt. Der innere Teil entspricht demjenigen nach Fig. 4 und ist mit entsprechenden Bezugszeichen bezeichnet. Auf diesen inneren Teil ist eine Konzentratorschale 18 aufgesetzt, die als zusätzlicher Kern für die äußere Erregerwicklung 15 wirkt. Die beiden Anordnungen addieren sich in ihrer Wirkung. Die Konzentratorschale 18 ist mit dem inneren Kern 11 bei 19 verbunden.5 and 6, another advantageous embodiment is shown. In this embodiment, two excitation windings 14 and 15 are nested concentrically with corresponding concentrator cores. The inner part corresponds to that according to FIG. 4 and is designated with corresponding reference numerals. A concentrator shell 18 is placed on this inner part, which acts as an additional core for the outer field winding 15. The two arrangements add up in their effect. The concentrator shell 18 is connected to the inner core 11 at 19.

Fig. 7 zeigt das Schaltbild eines mit Thyristoren Ti, T2 arbeitenden Pulsgenerators, mit dem ein nach den Fig. 5 und 6 aufgebautes System erprobt wurde. Die Spannungsquelle mit der Spannung UO lädt den Kondensator CL, der periodisch über die parallel als steuerbare Schalter wirkenden Thyristoren Ti, T2 in die Lastinduktivität LL des Flußkonzentrators entladen wird (Induktivität der Erregerspulen) und aufgrund des so entstehenden pulsförmigen Stromflusses dort das gewünschte Nutzfeld mit der Induktion B bewirkt.FIG. 7 shows the circuit diagram of a pulse generator working with thyristors Ti, T 2 , with which a system constructed according to FIGS. 5 and 6 was tested. The voltage source with the voltage UO charges the capacitor C L , which is periodically discharged via the thyristors Ti, T 2 acting in parallel as controllable switches into the load inductance L L of the flux concentrator (inductance of the excitation coils) and, due to the pulse-shaped current flow thus created, the desired one there Effective field with induction B.

Fig. 8 zeigt einen mit einem Konzentratoraufbau nach den Fig. 5 und 6 und einem Pulsgenerator nach Fig. 7 erhaltenen Verlauf der Induktion B über der Achse des Flußkonzentrators. Die angegebenen Abmessungen in Millimeter entsprechen einer in der Praxis erprobten Ausführungsform. Bei dieser wurden zwei Erregerwicklungen mit je zehn Windungen mit je einem Strom von 10 000 A betrieben. Die Windungen der Erregerwicklungen wurden direkt wassergekühlt. Bei einem Betrieb mit einer Pulsfolgefrequenz von 50 Hz und einer Pulsdauer beträgt die Verlustleistung ca. 5 kW.FIG. 8 shows a curve of the induction B over the axis of the flux concentrator obtained with a concentrator construction according to FIGS. 5 and 6 and a pulse generator according to FIG. 7. The dimensions given in millimeters correspond to an embodiment that has been tried and tested in practice. In this, two excitation windings with ten windings each with a current of 10,000 A were operated. The turns of the excitation windings were directly water-cooled. When operating with a pulse repetition frequency of 50 Hz and a pulse duration, the power loss is approx. 5 kW.

Wird nun eine sich außen auf dem Kern des Flußkonzentrators nach Fig. 4 befindliche Wicklung 14 in Pfeilrichtung von einem pulsförmigen Strom durchflossen, so wird nach dem Transformatorprinzip ein Strom in Gegenrichtung in den elektrisch gut leitenden Kern induziert (siehe Pfeilrichtung dort), der als Pulsstrom nur an der Oberfläche des Kerns fließt. An der Stelle des radialen Schlitzes 3 wird der Stromfluß nach innen um die Nutzfeldbohrung 12 in der dargestellten Pfeilrichtung erzwungen. Hier baut sich das gewünschte sehr starke Magnetfeld auf.If a winding 14, which is located on the outside of the core of the flux concentrator according to FIG. 4, now flows through in the direction of the arrow, a current is induced in the opposite direction into the electrically conductive core (see arrow direction there), which acts as the pulse current only flows on the surface of the core. At the location of the radial slot 3, the current flow is forced inwards around the useful field bore 12 in the direction of the arrow shown. The desired very strong magnetic field builds up here.

Die in Fig. 2 dargestellte Beschleunigereinheit arbeitet so, daß zuerst die Dosierspule 7 kurzzeitig stromlos wird (siehe auch oberes Zeitdiagramm in Fig. 3), so daß auch die Induktion B dieser Dosierspule verschwindet. Das Strahlmittel wird freigegeben und setzt sich in Bewegung. Wird nun gleichzeitig der als Beschleuniger wirkende magnetische Flußkonzentrator 6 erregt (siehe auch unteres Zeitdiagramm in Fig. 3), so wird unter dem Einfluß der sehr viel höheren Induktion B des Flußkonzentrators eine kräftige Beschleunigung des Strahlmittels einsetzen. Diese ist nur während der Pulsdauer in der Beschleunigerspule wirksam. Diese Pulsdauer muß gerade so eingestellt werden, daß beim Austritt des Strahlmittels aus dem Flußkonzentrator der Puls beendet ist. Wird nun mit dem Ende des Beschleunigerpulses synchron die Dosierspule 7 wieder erregt, so setzt ihre Haltewirkung wieder ein (siehe oberes Zeitdiagramm In Fig. 3). Auf diese Weise wird der Zufluß weiteren Strahlmittels unterbunden. Insgesamt ergibt sich eine periodisch pulsförmige Beschleunigung von Strahlmittelpaketen mit der Periodendauer T (siehe Fig. 3), die z.B. 20 ms betragen kann. Dieses entspricht einer Pulsfolgefrequenz von 50 Hz.The accelerator unit shown in Fig. 2 works so that the metering coil 7 is briefly de-energized (see also the upper timing diagram in Fig. 3), so that the induction B of this metering coil also disappears. The abrasive is released and starts to move. If the magnetic flux concentrator 6 acting as an accelerator is excited at the same time (see also the lower time diagram in FIG. 3), a strong acceleration of the blasting agent will start under the influence of the much higher induction B of the flux concentrator. This is only effective during the pulse duration in the accelerator coil. This pulse duration must be set so that the pulse ends when the blasting agent emerges from the flow concentrator. If the metering coil 7 is now excited again synchronously with the end of the accelerator pulse, its holding action resumes (see upper timing diagram in FIG. 3). In this way, the inflow of further blasting media is prevented. Overall, there is a periodic, pulse-shaped acceleration of blasting agent packets with the period T (see FIG. 3), which e.g. Can be 20 ms. This corresponds to a pulse repetition frequency of 50 Hz.

In Verbindung mit der Verwendung eines Flußkonzentrators und ggf. einer stromaufwärts angeordneten Dosierspule, kann eine Meßspule verwendet werden, die bei der Ausführungsform nach Fig. 2 zwischen den Spulen 6 und 7 angeordnet ist. Diese Meßspule erfaßt eintretendes Strahlmittel als elektrisches Signal, um in der in Bewegungsrichtung folgenden Beschleunigerspule (in Fig. 2 mit 6 bezeichnet) einen Stromimpuls zu zünden. Hierdurch wird eine besonders wirtschaftliche und genaue Steuerung möglich.In connection with the use of a flux concentrator and possibly a metering coil arranged upstream, a measuring coil can be used, which is arranged between the coils 6 and 7 in the embodiment according to FIG. 2. This measuring coil detects incoming blasting media as an electrical signal in order to ignite a current pulse in the accelerator coil following in the direction of movement (designated 6 in FIG. 2). This enables particularly economical and precise control.

Claims (4)

1. Apparatus for accelerating a blasting abrasive comprising magnetically influenceable particles, particularly iron particles, for treating material surfaces with one or more electromagnetic accelerating coils arranged along the blasting abrasive path and which can be energized or de-energized as a function of the moving blasting abrasive, characterized in that each accelerating coil is a per se known flow concentrator.
2. Apparatus according to claim 1, characterized in that upstream of the first flow concentrator (6) is placed a dosing coil (7).
3. Apparatus according to claims 1 or 2, characterized in that a measuring coil is positioned upstream of the accelerating coil in the blasting abrasive movement direction and which detects the entering blasting abrasive as an electric signal in order to ignite a current pulse in the acceleration coil following in the movement direction.
4. Apparatus according to claims 1, 2 or 3, characterized in that two or more exciting windings (14, 15) are concentrically interleaved and between in each case two such exciting windings is arranged a concentrator sleeve (18) as the core and which is connected to the inner concentrator core (11).
EP87111743A 1986-08-28 1987-08-13 Device for accelerating magnetic blasting materials Expired - Lifetime EP0261376B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE3629255A DE3629255C1 (en) 1986-08-28 1986-08-28 Device for accelerating abrasive that can be influenced magnetically
DE3629255 1986-08-28

Publications (3)

Publication Number Publication Date
EP0261376A2 EP0261376A2 (en) 1988-03-30
EP0261376A3 EP0261376A3 (en) 1989-01-18
EP0261376B1 true EP0261376B1 (en) 1990-06-13

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Family Applications (1)

Application Number Title Priority Date Filing Date
EP87111743A Expired - Lifetime EP0261376B1 (en) 1986-08-28 1987-08-13 Device for accelerating magnetic blasting materials

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EP (1) EP0261376B1 (en)
DE (2) DE3629255C1 (en)

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2698576B1 (en) * 1992-11-30 1995-02-17 Framatome Sa Method and device for repairing a defective area of the wall of a metal part and in particular of a tubular part.
US6561874B1 (en) * 2000-11-22 2003-05-13 Qed Technologies, Inc Apparatus and method for abrasive jet finishing of deeply concave surfaces using magnetorheological fluid
SG10201602833VA (en) 2016-04-11 2017-11-29 Abrasive Eng Pte Ltd Magnetic Valve for Shot Peening
TWI790473B (en) * 2020-08-28 2023-01-21 態金材料科技股份有限公司 Method of Cutting with Metallic Glass Particle Beam

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US754637A (en) * 1902-06-25 1904-03-15 Kristian Birkeland Electromagnetic gun.
CH240861A (en) * 1944-06-17 1946-01-31 Bbc Brown Boveri & Cie Device for generating a jet of iron shot at high speed.
GB1084496A (en) * 1965-06-15 1967-09-20 British Steel Castings Res Ass Improved method of and equipment for shot-blasting and the like
DE3324710C1 (en) * 1983-07-08 1984-05-30 Jost Dipl.-Ing. 2150 Buxtehude Wadephul Device for accelerating blasting media

Also Published As

Publication number Publication date
EP0261376A2 (en) 1988-03-30
DE3763157D1 (en) 1990-07-19
EP0261376A3 (en) 1989-01-18
DE3629255C1 (en) 1987-04-02

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