EP0404795B1 - Dosing gun, in particular high-pressure dosing gun - Google Patents

Abstract

PCT No. PCT/EP89/00286 Sec. 371 Date Sep. 12, 1990 Sec. 102(e) Date Sep. 12, 1990 PCT Filed Mar. 17, 1989 PCT Pub. No. WO89/08505 PCT Pub. Date Sep. 21, 1989.A dosing gun (500) comprising a revolving valve element (518), arranged fixedly in a first casing (506) which is immovably connected with the gun housing (502). The first casing (506) has a second spring-loaded casing (544) linked to it in a mobile way, which contains a hollow cylinder (514) having on its frontal part valve seats (542, 554). The dosing gun (500) can operate with or without a supply of compressed air.

Description

The invention relates to a dosing gun, in particular a high-pressure dosing gun for spraying a medium such as polishing paste, according to the preambles of claims 1, 10, 17 and 19.

DE-C-22 04 942 shows for the first time a high-pressure metering gun, in which a pressure is generated by means of a compressed air motor in a storage chamber that receives the medium to be sprayed, such as polishing paste, by means of which the movement of the valve body, such as the valve piston, is determined. For this purpose, the medium surrounds the valve piston at least in the region of the valve seat, so that, depending on the prevailing pressure, the valve piston is spaced apart from or rests on the valve seat, in order to selectively spray or retain the medium.

If the medium is sprayed without the addition of air, this is referred to as an "airless" process. Before the medium can be sprayed, the high-pressure dispensing gun must be vented. For this purpose, separate valves are sometimes required or the air is expelled at the beginning of the spraying process, so that during reproducible delivery of the medium does not take place during this time.

DE-A-32 02 189 shows a high-pressure metering gun in which the valve body is arranged in a stationary manner and the nozzle, which is pressurized by means of a spring and has the valve seat, can be placed on the valve piston or can be spaced apart therefrom. The spring coaxially surrounds the nozzle and is fixed by a union nut. A construction in this regard has proven to be extremely disadvantageous. Another deficiency of the gun in this regard is that the seal between the valve body and a relatively displaceable portion of a nozzle-receiving cylinder element takes place, which results in a relatively large sealing surface, from whose large forces result, which in turn by a spring element with a correspondingly high Force must be compensated or balanced. This results in the risk that even with slight leaks in the valve seat or the seal itself an insufficient internal pressure can be built up to displace the cylinder element. Especially when using or operating with abrasive media such as polishing paste, it is of great importance that the valve device is opened sufficiently, since otherwise, despite the use of hard metals or the like, a self-destructive effect will occur due to uneven washouts on the valve seat or valve stem, which will still wear out accelerates. In addition, the manual opening of the valve device required for commissioning for venting the system is only possible with an additional special tool. For the operation of such a device with atomizing air, the necessary sensitivity is missing in order to achieve uniformly good meterability, which is desired. This cannot be achieved with the device shown in DE-A-32 02 189.

Corresponding high-pressure metering guns also have the disadvantage that frequent replacement of the wearing parts such as the valve body or of a valve element having the valve seat, such as a perforated disk, is necessary. Then you can There may be structural disadvantages if the valve body is designed as a hollow needle through which the medium to be dispensed flows.

It is an object of the present invention, inter alia, to further develop a metering gun, in particular according to the preamble of claim 1, in such a way that interchangeability of the wearing parts is reduced or, if the closing parts have to be replaced, this can be done simply and without problems that with structurally simple means there is a high reproducibility of the media to be sprayed, with small sealing surfaces in particular being selected in order to be able to better control the forces which occur. A simple exchange of possibly worn parts should also be possible. Finally, there should also be the option of operating the metering gun either in an "airless" process or with the addition of compressed air. It is also an object of the invention, in particular in the case of a metering gun, to carry out venting with simple means, both rapid venting and, if appropriate, permanent venting to be possible. Furthermore, the nozzle should be adjustable with simple means without the need for tightening union nuts or the like.

The task or the subtasks are essentially solved by the features to be extracted from the characteristics of claims 1, 10, 17 and 19.

In particular, the invention is characterized in that the valve body is detachably received by a first sleeve forming a unit with it, that the first sleeve extends from the cartridge body or the housing and that the valve seat is formed in the end region of a hollow cylinder which can be displaced relative to the first sleeve which forms a unit with a second sleeve which is displaceable against the spring element and with respect to the first sleeve. The medium, in particular, can flow around the valve body and is supported with respect to the first sleeve via spacer elements, which in turn are an integral part of the valve body. In particular, it is provided that the valve body with the spacer elements both with respect to the main axis and the secondary axis are symmetrical. The same applies to the hollow cylinder having the valve seat.

The second sleeve receiving the hollow cylinder has one or more leakage holes, which firstly prevent medium penetrating between the hollow cylinder and the first sleeve from collecting and impairing the mobility of the device, and secondly indicate that a revision of the seal and the hollow cylinder or the valve seat must be done.

In particular with regard to the last-mentioned features, there is the advantage that the wearing parts are reversible, so that double use in comparison with known devices is possible. In other words, a reversing valve body and a reversing hollow cylinder are provided, the end regions of which each have the valve seat. The first working chamber, which has the medium and runs between the valve seat and the valve body, is sealed on the outside of the hollow cylinder, preferably by means of a grooved ring. As a result, only a small sealing surface is required, so that the forces that occur can be better controlled.

In an embodiment it is provided that a second working chamber is formed between radially extending sections of the first and second bushings in such a way that when the compressed air is applied, the second bushing can be displaced against the force of the spring element, with a connection between the working chamber and the outlet channels in the region of the nozzle consists. In other words, the dispensing gun according to the invention can be operated both in the "airless" process and with admixture of compressed air.

The hollow cylinder having the valve seats has a nylon gasket which conically widens on the outside in some areas and can be placed on the inner surface of the nozzle. The outer geometry of the nylon seal is appropriately designed Adjusted section of the second sleeve, on the outside of which a nut tightening the nozzle in the direction of the seal can be screwed. This provides a secure fixing of the hollow cylinder with the seal and nozzle with respect to the second sleeve, which surrounds the first sleeve in some areas and is displaceable along this.

The second sleeve is in turn surrounded by a further union nut, which starts from the cartridge body or the housing. The spring element that pressurizes the second sleeve in the direction of the housing runs in the area between the second union nut and the outside of the second sleeve. A stop is preferably provided in the front end region of the second union nut, which limits the axial displacement of the second bushing and thus of the valve seat away from the housing or the valve body.

In a dispensing gun according to the preamble of claim 10, in which the valve body is displaceable against the force of a spring element with respect to the cartridge body or the housing, it is proposed according to the invention that the nozzle is rotatable and axially displaceable against the force of the spring element Union nut is added. Furthermore, a disk element having the valve seat is designed to be floating against the nozzle.

The teaching according to the invention provides the possibility of using a tool such as a conventional screwdriver to create a leverage effect between the union nut, which is also referred to as the nozzle nut, and the nozzle itself, by means of which the nozzle is displaced into the interior of the high-pressure metering gun. This allows the air present in the lines of the device and in connected hose lines to escape. As soon as the tool is removed, the valve device closes automatically, ie the valve body rests against the valve seat, so that an adequate seal takes place.

According to a further embodiment, the first union nut receiving the nozzle is fastened to a further union nut which can be screwed onto the cartridge body or the metering gun housing, the front opening of which, facing the first union nut, is adapted to the diameter of the contact collar of the nozzle. This area is designed to protrude from the adjoining section of the second union nut, so that the valve element, like the perforated disk, can fit on the inside. This has the advantage that when the nozzle is removed, i.e. when the first union nut is unscrewed, the valve body is still in contact with the valve seat, that is to say an adequate seal is guaranteed against uncontrolled spraying of the medium, since the valve disk is held by the end section of the second union nut is.

The valve body itself is preferably slidably mounted in a valve piston guide, which has an internal, replaceable wear bushing that interacts with the valve body.

The seal between the first working chamber, which has the medium and runs between the valve seat and the valve body, is provided by a circumferential seal provided in the area of the wear bushing in the wall of the valve body. This also only requires a small sealing surface, so that a sensitive opening or closing of the nozzle is ensured.

Essential parts of the valve device such as valve body, valve piston guide, wear bushing and a spring plate interacting with the spring element are only inserted. All parts can be easily removed and replaced with the second union nut removed. This simplifies the maintenance of the dispensing gun.

Regarding the possibility of simple adjustment of the nozzle according to the invention, reference is made to the following. The usual Airless nozzles used do not spray an omnidirectional jet in most cases, but a fan shape. In this case, the nozzle must therefore be aligned radially. In the known devices, the nozzle is tightened on its fastening collar with the aid of a union nut, which usually itself has to be held with a separate key in order to prevent rotation. Due to the teaching according to the invention, the complex measures are no longer required, since the force of the spring element acts continuously through the spring plate, the valve piston and the valve seat up to the contact collar of the nozzle and the nozzle lies sealingly against the facing wall of the union nut. The nozzle can then be rotated into any desired position, for example with an open-ended wrench, which engages on a key surface attached to the nozzle, without first having to loosen or subsequently tighten the union nut.

In order to be able to operate a metering gun either with or without admixture of compressed air, it is provided that the valve body is at least partially surrounded by a hollow guide cylinder, that the valve body and the hollow guide cylinder are displaceable relative to one another, that between a valve element having the valve seat is fixed to the hollow guide cylinder and the nozzle, and that a further working chamber is arranged between the hollow guide cylinder and an element connected to it and an element holding or emanating from the valve body, with compressed air for the displaceability of the valve body relative to the valve element can be acted upon, the further working chamber being connected to the air outlet channels in the region of the nozzle.

With the dispensing gun according to the invention, various spraying and dispensing processes can be carried out as required without changing the basic structure. The dispensing gun is suitable for aggressive, abrasive, low and high viscosity substances. Depending on the type of spraying process, the other working chamber is connected to a compressed air source or not. The Components of the dispensing gun are structurally simple and therefore economical to manufacture. The entire dispensing gun can be dismantled quickly and easily. That is why the parts that are subject to greater wear in the case of abrasive materials can be replaced quickly and easily.

Further features to be particularly emphasized - individually and / or in combination - can be found in particular in the dependent claims.

The invention is explained in more detail below with reference to preferred exemplary embodiments illustrated in the drawing, from which further details, advantages and features likewise result.

Fig. 1

eine erste Ausführungsform einer Dosierpistole in perspektivischer Darstellung,

Fig. 2

die Dosierpistole nach Fig. 1 in Seitenansicht, teilweise im Längsschnitt,

Fig. 3

eine zweite Ausführungsform einer Dosierpistole,

Fig. 4

eine dritte Ausführungsform einer Dosierpistole mit axial verschiebbarem Ventilkörper,

Fig. 5

eine besonders hervorzuhebende Ausführungsform einer Dosierpistole,

Fig. 6

die Dosierpistole nach Fig. 5, jedoch mit Druckluftbeimischung,

Fig. 7

eine Detaildarstellung eines Rückschlagventils,

Fig. 8

eine Detaildarstellung einer für eine Dosierpistole bestimmten Ventileinrichtung und

Fig. 9

eine besonders hervorzuhebende Ausführungsform eines Ventilkörpers in Form eines Wendeelementes.

Show it:

Fig. 1

a first embodiment of a dosing gun in a perspective view,

Fig. 2

1 in side view, partially in longitudinal section,

Fig. 3

a second embodiment of a dosing gun,

Fig. 4

A third embodiment of a dosing gun with an axially displaceable valve body,

Fig. 5

a particularly noteworthy embodiment of a dispensing gun,

Fig. 6

5, but with the addition of compressed air,

Fig. 7

a detailed representation of a check valve,

Fig. 8

a detailed representation of a valve device intended for a dosing gun and

Fig. 9

a particularly noteworthy embodiment of a valve body in the form of a turning element.

1 and 2 is a dispensing gun (1) for spraying liquid or pasty substances, i.e. Substances that have different viscosities are shown. The dosing gun (1) contains a housing (2), with one side of which a compressed air piston-cylinder device (3) is connected. A valve device (4) is arranged on the opposite side of the housing (2). A check valve (5) is attached to another side of the housing. With the check valve (5) a shut-off valve (6) is connected, which contains a connection piece (7) for a hose, which is not shown in detail and is laid to a source for the substance to be sprayed or sprayed, which is under pressure . The compressed air piston-cylinder device (3) contains a hollow cylinder (8) which is closed on one side by a sealed washer (9) which is fastened to the cylinder (8) with a union nut (10).

In the disc or on the cover (9) a connecting piece for a hose, not shown, is attached, which is connected via a control valve, in particular a three-way valve, which is also not shown, to a compressed air source for particularly low pressure. In the middle of the disc (9) a stop spindle (12) is arranged, which has an outside of the compressed air piston-cylinder device (3) arranged adjusting nut (13) with which the axial immersion depth of the stop spindle (12) inside the Cylinder (8), which is also called hollow cylinder (8) below, can be set.

The shut-off valve (6) has an operating handle, not shown. A threaded bore (14) is provided in the housing (2) for screwing in a further connection piece, not shown, which also does not have a connection hose shown is connected to the mentioned or a further compressed air source.

A hollow threaded pin (15) of the check valve (5) is screwed into a threaded bore of the housing (2), which is not specified in any more detail. This threaded bore tapers at its end arranged in the housing (2) and is connected via an opening (16) to a cylindrical cavity (17) which extends through the housing and has sections of larger diameter, which are not specified, at its ends. One of these sections, which is located on that side of the cavity (17) which faces away from the compressed air piston-cylinder device (3), has an internal thread. A cartridge-shaped insert (18) is screwed into this internal thread and has a section (19) protruding into the cavity (17), in which a cylindrical storage chamber (20) is arranged, which via a passage (21) in the section (19) is connected to a free space (22) in the cavity (17). The opening (16) opens into the free space (22).

A plunger (23) is arranged longitudinally displaceably in the storage chamber (20), the end facing away from the storage chamber (20) is held in a piston (24), which is displaceably mounted in the interior of the hollow cylinder (8). A seal (25) is arranged in the cylindrical, unspecified wall of the piston (23). The piston (24), the inner wall of the hollow cylinder (8) and the disc (9) enclose a working chamber (26) which is accessible for gases via the connecting piece (11).

The hollow cylinder (8) is closed at its end facing away from the disk (9) with a circular flange (28) inserted into the cylindrical cavity and fastened to the wall thereof with a locking ring (27), which has an unspecified passage opening for the plunger (23). The flange (28) contains unspecified bores which run parallel to the longitudinal axis of the hollow cylinder (8) and into which screws (29) are inserted which are screwed into threaded bores in the housing (2). The flange (28) and the housing (2) are each provided with aligned leakage holes, not shown. In addition, ventilation bores for the cylinder, which are not specified, are provided.

The cylindrical storage chamber (20) tapers at one end to an unspecified, axially identical threaded bore into which a hollow needle (30), also to be referred to as a valve body, is screwed with an end section (31) provided with an external thread. The hollow needle (30), which has a central channel (32) running in the longitudinal direction, belongs to the valve device (4). At the mouth of the channel (32) into the storage chamber (20), a closure seal (33) is inserted into a recess. The hollow needle (30) contains a central section (34) provided with a molded-on nut head, to which the end section (35) having the second cylindrical shape adjoins, the outside of which is at least partially designed as a guide surface (36).

The insert (18) projects with a section (37) beyond the housing (2). Inside the section (37) there is a hollow cylinder (38) which is a guide surface for a section (39) of a sliding body (40). A seal (41) is arranged in the wall of the cylinder (38). The sliding body (40) has a step which is set back radially inwards against the section (39), as a result of which there is a free space between the wall of the cylinder (38) and the sliding body (40). In this free space, a spiral spring (42) is inserted, one end of which is supported on the annular wall of the step at section (39). The other end of the spiral spring (42) is supported on a union nut (43) which is screwed onto an external thread of the section (37) and has a central passage for the part of the sliding body (40) which projects beyond the section (37). The sliding body (40) is provided in its interior with a cavity (44) in which the middle section (34) is located. The wall of the section (39) facing the housing (2) forms, with the walls of the cylinder (38), a further working chamber (45) which, via a channel (46) in the insert (18) with the threaded bore (14) connected is. In section (19) a seal (47) is provided which seals the channel (46) and the working space (45) against the space (22) in which the substance to be sprayed or sprayed is located. The cavity (44) tapers into a cylindrical guide surface (48), that is to say a so-called hollow guide cylinder, which surrounds the guide surface (36) on the valve body (30). A seal (49) is arranged in the guide surface of the hollow guide cylinder (48).

The channel (32) is angled radially outwards in the vicinity of the end of the hollow needle (30) protruding from the housing (2) and has an opening into a cavity (51) which is formed by a cylindrical recess in the sliding body (40) becomes. The diameter of this cavity (51) is larger than the diameter of the hollow guide cylinder (48). The cavity (51) extends up to the end face (52) of the sliding body (40).

A valve plate (53), which closes the front opening of the cavity (51) and has a central passage opening (54), bears against the end face (52). The edge of this passage opening (54) is designed as a valve seat surface for a valve head (55) which is located at that end of the valve body (30) or the hollow needle which protrudes from the housing (2). The valve head (55) can be an integral part of the hollow needle (30). It is also possible to attach a separate valve head (55) to the end of the hollow needle (30). The valve head (55) is preferably spherical or hemispherical.

The sliding body (40) is provided at its end facing away from the housing (2) with an external thread, not specified, onto which a union nut (56) is screwed, which insert (57) with a nozzle (58) against the valve plate (53 ) and presses it against the end face (52).

In addition to the nozzle (58), the insert (57) contains air outlet channels (59) which run to an annular cavity (60) which is located between the inner end face of the insert (57), the union nut (56), the valve plate (53) and the end face (52) is arranged. The ring cavity (60) is connected to the cavity (44) via a channel (61).

Above the check valve (5) there is a nut-shaped screw connection (63) at the deflection point of the channel for the material transport leading to the shut-off valve (6). In an extension (64) of the screw connection (63) there is a pressure sensor, not shown, which has an optical display element (65) for the pressure. Electrical detection and e.g. digital display of the pressure.

Another pressure sensor (62) is connected to the storage chamber (20) with a sensor element inside. The pressure values can be evaluated electronically and used to monitor the function of the entire system.

In addition to FIG. 2, it should also be noted that the hydraulic unit, which comprises the cartridge and the valve device, can be separated from the compressed air motor via a grooved ring (123), which results in a high degree of serviceability.

• 1. Zum kontinuierlichen Sprühen eines Stoffes wird der in Verbindung mit der Fig. 2 näher beschriebene Einsatz (57) verwendet. Die Gewindebohrung (14) ist über ein nicht näher dargestelltes Dreiwegeventil mit der Druckluftquelle verbunden. Der Arbeitsraum (26) ist über den Anschlußstutzen (11) an atmosphärischen Luftdruck gelegt. Über die Gewindebohrung (14) und den Kanal (46) gelangt Druckluft in die Arbeitskammer (45). Von dort strömt die Druckluft über den Hohlraum (44) und den Kanal (61) zum Ringhohlraum (60), aus dem sie über die die Düse (58) in gleichmäßigen Abständen umgebenden Luftauslaßkanäle (59) entweicht. Die der Arbeitskammer (45) zugewandte ringförmige Stirnfläche des Abschnitts (39) ist unter Abstimmung auf die aus den Luftauslaßkanälen (59) austretende Luftmenge so groß ausgebildet, daß der sich in der Arbeitskammer (45) aufbauende Druck ausreicht, um den Schiebekörper (40) entgegen der Kraft der Spiralfeder (42) um ein geringes Stück, z.B. 2 mm, zu verschieben. Hierdurch wird die Ventilplatte (53) vom Ventilkörper (55) abgehoben. Es entsteht ein Durchlaß an dem die Ventilplatte (53) und den Ventilkörper (55) enthaltenden Ventil. Der zu versprühende Stoff wird unter Druck in die Vorratskammer (20) gefördert und strömt von dort durch den Kanal (32) in den Hohlraum (51). Durch die Öffnung des Ventils gelangt daher zu versprühendes Medium kontinuierlich zur Düse (58), aus der das Medium austritt und in den Einwirkungsbereich der aus den Luftauslaßkanälen (59) austretenden Druckluft gelangt, mit der das Medium ein Luft-Materialgemisch bildet, das unter Druck als Sprühnebel auf einen Gegenstand aufgebracht werden kann.
• 2. Weiterhin ist mit der in Fig. 1 und 2 gezeigten Dosierpistole (1) ein Sprühen eines viskosen Stoffes möglich, der ein genau vorgegebenes Volumen aufweist, das durch die axiale Lage der Anschlagspindel (12) bestimmt wird. Durch eine nicht näher dargestellte Skala an der Stellmutter (13) wird das über die Anschlagspindel (12) einstellbare Volumen der Vorratskammer (20) angezeigt. Der Anschlußstutzen (11) ist bei der Ausübung des vorstehend erwähnten Verfahrens z.B. über ein Dreiwegeventil in gleicher Weise wie die Gewindebohrung an die Druckluftquelle angeschlossen. Unter dem Druck, mit dem der zu versprühende Stoff gefördert wird, füllt sich die Vorratskammer mit dem Stoff, bis der Kolben (24) an der Anschlagspindel (12) anliegt. Eine Feder zum Zurückziehen des Kolbens (24) in seiner einen Endlage erübrigt sich daher. Danach werden die Arbeitskammern (26) und (45) mit Druckluft versorgt, die sich gleichmäßig auf die Arbeitskammern (26) und (45) verteilt. Die Ventileinrichtung (4) arbeitet in gleicher Weise wie oben bereits beschrieben. Der Kolben (26) schiebt den Stößel (23) in die Vorratskammer (20), wodurch sich in dieser ein Druck aufbaut, durch den das Rückschlagventil (5) geschlossen wird. Deshalb wird kein weiterer Stoff mehr in die Vorratskammer (20) eingespeist. Der Stößel (23) verdrängt die in der Vorratskammer (20) vorhandene viskose Stoffmenge, die über den Kanal (32) und das Ventil zur Düse (58) strömt, bis die Stirnseite des Stößels (23) an der Verschlußdichtung (33) anliegt. Anschließend werden die Arbeitsräume (26) und (45) an atmosphärischen Luftdruck gelegt. Dies hat zur Folge, daß die Ventileinrichtung (4) schließt und das Rückschlagventil (5) öffnet. Es gelangt unter Druck erneut Stoff über eine Ringkammer (67) in der Vorratskammerwand zur Stirnseite des Stößels (23), der durch den in der Vorratskammer (20) einströmenden Stoff aus dieser verdrängt wird, bis sich der Kolben (24) gegen die Anschlagspindel (12) legt. Danach kann der oben beschriebene Vorgang wiederholt werden.
  Die Druckluftzufuhr zum Arbeitsraum (26) kann durch eine nicht dargestellte Eingangsluftdrossel reduziert werden, um den Druck im Arbeitsraum (26) gerade so hoch werden zu lassen, daß das Rückschlagventil (5) schließt und der Stößel (23) bis zur Verschlußdichtung (33) bewegt wird.
• 3. Ein kontinuierliches Sprühen mit Niederdruck ohne Beimischung von Druckluft mit Hilfe des Materialförderdruckes (Klecksen) setzt voraus, daß keine Luftauslaßkanäle (59) vorhanden sind. Es wird z.B. ein entsprechender Einsatz ohne Luftauslaßkanäle (59) in die Vorrichtung (1) eingebaut. Es ist auch möglich, eine Dichtung im Ringhohlraum (60) vorzusehen, durch die die Luftauslaßkanäle (59) abgedichtet werden. Die Druckluft gelangt in die Arbeitskammer (45) und bewegt den Schiebekörper (40) in die Ventilöffnungsstellung gegen die Kraft der Spiralfeder (42). Hierbei kann Stoff aus der Vorratskammer (20) über den Kanal (32) und den Hohlraum (51) zum offenen Ventil gelangen, aus dem er in die Düse (58) übertritt. Die aus der Düse pro Zeiteinheit austretende Stoffmenge hängt vom Druck in der Vorratskammer (20) bzw. dem Materialförderdruck ab. Die Sprühdauer wird vorzugsweise durch ein Zeitrelais gesteuert, mit dem die Zufuhr von Druckluft zum Arbeitsraum (45) unterbrochen wird, wodurch sich die Ventileinrichtung (4) schließt.
• 4. Eine Volumendosierung beim Sprühen mit Niederdruck ohne Druckluftbeimischung mit Hilfe des Materialförderdrucks (Klecksen) wird erreicht, wenn die Arbeitskammer (26) in gleicher Weise wie bei dem unter Punkt 2. erwähnten Verfahren mit Druckluft versorgt wird. Um keinen unerwünscht hohen Druck in der Arbeitskammer (26) zu erzeugen, wird die Druckluftzufuhr gedrosselt, wenn die vorgegebene Stoffmenge aus der Vorratskammer (20) verdrängt wird.
• 5. Zum Hochdrucksprühen des Stoffes ohne Druckluftbeimischung wird der Arbeitsraum (45) an atmosphärischen Druck gelegt.
  Die Arbeitskammer (26) wird über ein nicht dargestelltes Steuerventil an Druckluft angeschlossen. Durch den Druck in der Arbeitskammer (26) bewegt der Kolben (24) den Stößel (23) in die Vorratskammer (20), wodurch sich ein Druck in dieser aufbaut, der das Rückschlagventil (5) schließt. Eine weitere Verschiebung des Stößels (23) führt zu einer Erhöhung des Druckes in der Vorratskammer (20), dem Kanal (32) und dem Hohlraum (51), bis der auf die Ventilplatte (53) wirkende Druck die Federvorspannung übersteigt. Hierdurch wird der Schiebekörper (20) in die Öffnungsstellung der Ventilvorrichtung (4) verschoben. Der aus dem Ventil austretende Stoff gelangt zur Düse (58) und tritt aus dieser unter hohem Druck aus, wobei er zerstäubt wird. Solange der hohe Druck im Stoff vorhanden ist, bleibt die Ventileinrichtung (4) geöffnet. Wenn der Kolben (26) am Flansch (28) anschlägt, fällt der Druck rasch ab, so daß die Ventileinrichtung (4) schließt. Durch den Kolben (24), der eine größere Angriffsfläche hat als der Stößel (23), wird der für das luftlose Zerstäuben (Airless) notwendige hohe Druck erzeugt.
• 6. Unter bestimmten Voraussetzungen ist es erforderlich, das Hochdruckzerstäuben (Airless) unter Beimengung von Druckluft in bestimmten Grenzen weiter zu beeinflussen. Dieses Verfahren wird als Airless-Verfahren mit Luftunterstützung bezeichnet. Bei diesem Verfahren sind die Arbeitskammern (26) und (45) zugleich mit Druckluft beaufschlagbar. Der Einsatz (57) enthält neben der Düse (58) wieder Luftauslaßkanäle (59). Zwischen der Gewindebohrung (14) und der Druckluftquelle ist jedoch eine Drossel angeordnet. Zunächst ist die Druckluftzufuhr zur Arbeitskammer (45), z.B. drucklos bzw. verschlossen. Wird die Druckluftzufuhr zur Arbeitskammer (26) freigegeben, entsteht ein Druckaufbau in der Vorratskammer (20), der sich in der oben unter Punkt 5. angegebenen Weise bis zum Hohlraum (51) fortsetzt und die Ventileinrichtung (4) öffnet. Danach kann über die Arbeitskammer (45) durch Öffnen der Drossel dem Hohlraum (44) und dem Kanal (61) sowie den Ringhohlraum (60) dem Einsatz (57) Druckluft zugeführt werden, die dem zerstäubten Stoff beigemischt wird. Damit wird ein Sprühnebel wie gewünscht beeinflußt. Je weiter die Drossel geöffnet wird, um so weniger Luft bzw. Druck steht für den Arbeitsraum (26) zur Verfügung, so daß der von dem Kolben (24) erzeugte hohe Druck parallel hierzu reduziert werden kann. Dabei sinkt auch der im Expansionsraum vorhandene Druck, und die Ventileinrichtung (4) könnte gegebenenfalls schließen, was aber durch die den Schiebekörper (40) über den Arbeitsraum (45) beeinflussende Druckluft ausgeglichen wird, die genügend Druck aufbaut, um die Ventileinrichtung (4) offen zu halten.

With the device described above, six different spraying or spraying processes can be carried out, which are described in more detail below.

• 1. The insert (57) described in more detail in connection with FIG. 2 is used for the continuous spraying of a substance. The threaded bore (14) is connected to the compressed air source via a three-way valve, not shown. The work space (26) is placed over the connecting piece (11) at atmospheric air pressure. Compressed air enters the working chamber (45) via the threaded bore (14) and the channel (46). From there, the compressed air flows via the cavity (44) and the channel (61) to the annular cavity (60), from which it escapes via the air outlet channels (59) surrounding the nozzle (58) at regular intervals. The annular chamber facing the working chamber (45) The end face of the section (39) is designed to be large enough in coordination with the amount of air emerging from the air outlet channels (59) that the pressure building up in the working chamber (45) is sufficient to push the sliding body (40) against the force of the spiral spring (42). to move a small distance, e.g. 2 mm. As a result, the valve plate (53) is lifted off the valve body (55). A passage is formed on the valve containing the valve plate (53) and the valve body (55). The substance to be sprayed is conveyed under pressure into the storage chamber (20) and flows from there through the channel (32) into the cavity (51). Through the opening of the valve, the medium to be sprayed therefore continuously reaches the nozzle (58), from which the medium emerges and into the area of action of the compressed air emerging from the air outlet channels (59), with which the medium forms an air-material mixture which is under pressure can be applied to an object as a spray.
• 2. Furthermore, with the dispensing gun (1) shown in FIGS. 1 and 2, it is possible to spray a viscous substance which has a precisely predetermined volume, which is determined by the axial position of the stop spindle (12). The volume of the storage chamber (20) that can be set via the stop spindle (12) is indicated by a scale on the adjusting nut (13), which is not shown in any more detail. The connection piece (11) is connected to the compressed air source in the same way as the threaded bore when carrying out the above-mentioned method, for example via a three-way valve. Under the pressure with which the substance to be sprayed is conveyed, the storage chamber fills with the substance until the piston (24) lies against the stop spindle (12). A spring for retracting the piston (24) in its one end position is therefore unnecessary. Then the working chambers (26) and (45) are supplied with compressed air, which is evenly distributed over the working chambers (26) and (45). The valve device (4) works in the same way as already described above. The piston (26) pushes the plunger (23) into the Storage chamber (20), whereby a pressure builds up in it, by means of which the check valve (5) is closed. Therefore, no further material is fed into the storage chamber (20). The plunger (23) displaces the viscous amount of substance present in the storage chamber (20), which flows through the channel (32) and the valve to the nozzle (58) until the end face of the plunger (23) abuts the closure seal (33). The working rooms (26) and (45) are then placed under atmospheric air pressure. The result of this is that the valve device (4) closes and the check valve (5) opens. Under pressure, material flows again through an annular chamber (67) in the storage chamber wall to the end face of the plunger (23), which is displaced by the material flowing into the storage chamber (20) until the piston (24) against the stop spindle ( 12) sets. Then the above procedure can be repeated.
  The supply of compressed air to the work area (26) can be reduced by an inlet air throttle, not shown, in order to let the pressure in the work area (26) become so high that the check valve (5) closes and the tappet (23) up to the sealing seal (33) is moved.
• 3. A continuous spraying with low pressure without admixing compressed air with the aid of the material delivery pressure (blobs) requires that there are no air outlet channels (59). For example, a corresponding insert without air outlet channels (59) is installed in the device (1). It is also possible to provide a seal in the annular cavity (60) through which the air outlet channels (59) are sealed. The compressed air enters the working chamber (45) and moves the sliding body (40) into the valve opening position against the force of the spiral spring (42). In this case, material can get from the storage chamber (20) via the channel (32) and the cavity (51) to the open valve, from which it passes into the nozzle (58). The amount of substance emerging from the nozzle per unit of time depends on the pressure in the Storage chamber (20) or the material delivery pressure. The spray duration is preferably controlled by a time relay, with which the supply of compressed air to the work space (45) is interrupted, as a result of which the valve device (4) closes.
• 4. A volume metering when spraying with low pressure without admixing compressed air with the aid of the material delivery pressure (blobs) is achieved if the working chamber (26) is supplied with compressed air in the same way as in the method mentioned under point 2. In order not to generate an undesirably high pressure in the working chamber (26), the compressed air supply is throttled when the predetermined amount of substance is displaced from the storage chamber (20).
• 5. For high-pressure spraying of the material without the addition of compressed air, the working space (45) is placed at atmospheric pressure.
  The working chamber (26) is connected to compressed air via a control valve (not shown). Due to the pressure in the working chamber (26), the piston (24) moves the plunger (23) into the storage chamber (20), as a result of which a pressure builds up in the latter, which closes the check valve (5). A further displacement of the plunger (23) leads to an increase in the pressure in the storage chamber (20), the channel (32) and the cavity (51) until the pressure acting on the valve plate (53) exceeds the spring preload. As a result, the sliding body (20) is moved into the open position of the valve device (4). The substance emerging from the valve reaches the nozzle (58) and emerges from it under high pressure, where it is atomized. The valve device (4) remains open as long as the high pressure is present in the fabric. When the piston (26) strikes the flange (28), the pressure drops rapidly so that the valve device (4) closes. By the piston (24), which has a larger contact surface than the plunger (23), the the high pressure required for airless atomization (airless).
• 6. Under certain conditions, it is necessary to influence the high pressure atomization (Airless) with the addition of compressed air within certain limits. This process is referred to as an air-assisted airless process. With this method, the working chambers (26) and (45) can also be acted upon with compressed air. In addition to the nozzle (58), the insert (57) again contains air outlet channels (59). However, a throttle is arranged between the threaded bore (14) and the compressed air source. First, the compressed air supply to the working chamber (45) is, for example, depressurized or closed. If the compressed air supply to the working chamber (26) is released, pressure builds up in the storage chamber (20), which continues in the manner specified under point 5 up to the cavity (51) and opens the valve device (4). Compressed air, which is mixed with the atomized substance, can then be fed to the cavity (44) and the channel (61) and the annular cavity (60) through the working chamber (45) by opening the throttle. This affects a spray as desired. The further the throttle is opened, the less air or pressure is available for the working space (26), so that the high pressure generated by the piston (24) can be reduced in parallel. The pressure in the expansion space also drops, and the valve device (4) could possibly close, but this is compensated for by the compressed air influencing the sliding body (40) via the working space (45), which builds up enough pressure to close the valve device (4). to keep open.

The stroke of the tappet (23) comes to a standstill at the seal (33) and is set to a desired value via the stop spindle (12) as in the dosing procedure described under points 2 and 4.

3 shows, in a purely schematic representation and partly in section, part of a further embodiment of a metering gun, in particular a high-pressure metering gun (200), which has a cartridge body (209) which can be detachably inserted into a gun body (212). A compressed air motor (not shown), for example of the type described above, is arranged in the gun body (212) in order to generate a pressure to the desired extent by moving a plunger which can be displaced in a medium to be sprayed. The medium to be sprayed, such as polishing paste, extends in the drawing in the dashed area to a valve head (213) of a valve body such as valve piston (205). The valve piston (205) is arranged to be axially displaceable in a valve piston guide (207) which comprises a wear bushing (206) along which the valve piston (205) can be moved. The seal between the valve piston (205) and the wear bushing (206) takes place via a seal (215) embedded in a groove (214). With its rear annular end wall (216), the wear sleeve (206) forms a stop for a spring plate (208), which interacts with its rear end wall (217) of the valve piston (205). The spring plate (208), which is open in the direction of the gun body (212), receives a compression spring (211) which is supported against a cover (210) which, when the dispensing gun (200) is mounted, is essentially immovable by being in contact with, for example stop not shown is set. The cover (210) has a U-shape in section, the circumferential edge (218) extending in the direction of the spring plate (208) being sealed off from the valve piston guide (207) having a hollow cylindrical shape. The force caused by the spring (211) clearly causes the spring plate (208) and thus the valve piston (205) to be displaced in the direction of a nozzle (202) which is received by a first union nut or nozzle nut (201). The nozzle nut (201) is in turn screwed to a second union nut (204) which in some areas surrounds the cartridge body (209) on the outside. The sealing between the union nut (204) and the cartridge body (208) takes place via a statically sealing O-ring seal (219).

The nozzle (202) has a contact collar (220) which bears on the inner surface of the first union nut (201). Between the valve head (213) of the valve piston (205) and the contact collar (202), a valve element having a valve seat (222), such as a perforated disc (203), is also floatingly mounted.

Depending on the pressure prevailing in the area of the valve head (213), which is generated by the compressed air motor and transmitted via the medium to be sprayed, the valve piston (205) can be lifted off the valve seat (203) against the force caused by the spring (211) so that the medium can be sprayed through the nozzle (202).

The end area of the second union nut (204) has a radially inwardly extending section (223), the inside diameter of which is larger than that of the contact collar (220), but smaller than that of the perforated disk (203).

The mode of operation of the features of the high-pressure metering gun (200) according to the invention is now as follows.

The nozzle (202) held by the first union nut or nozzle nut (201) can be pressed against the nozzle (202) by means of a screwdriver which can be inserted into a recess (221) provided in the nozzle nut (201), whereby the nozzle ( 202) is shifted inwards. The perforated disc (203), including the valve piston (205), which is floating against the nozzle (202) and has a valve seat (222), is displaced against the force of the closing spring (211). By lifting the contact collar (220) of the nozzle (202) from the inner surface of the nozzle nut (201), the seal on the inner surface of the nozzle nut (201) is released, so that air present in the valve device can escape past the nozzle jacket. If the tool is removed from the recess (221), the valve device closes automatically, since the force of the spring (211) causes the spring plate (208) via the valve piston (205) and the valve seat (202) or Perforated disc (203) causes a force on the contact collar (220) for sealing contact with the union nut (201).

If permanent ventilation is desired, the union nut (204) is loosened by the cartridge body (209) until the spring plate (208) lies against the stop (216) of the wear bushing (206). If the union nut (204) is unscrewed further, the spring force can no longer act on the valve piston (205), so that the closing force of the valve piston (205) or the valve head (213) on the valve seat (222) is canceled and thus any air that may be present can escape through the perforated disc (203) and the nozzle.

If only the nozzle nut (201) with the nozzle (202) e.g. removed for renewal, the interior of the dispensing gun (200) is still sealed, so it can be under pressure. The reason for this is that the perforated disk (203) continues to bear against the inner surface of the radially inwardly projecting section (223) of the second union nut (204). As a result, the valve head (213) lies close to the valve seat (222) and closes the interior.

4 shows further particularly noteworthy configurations of the invention. The same reference numerals have been chosen for elements that can already be seen in FIGS. 1 and 2.

A hollow cylinder section (70) extends from the housing (2) and extends in the direction of the valve device (4). The hollow cylinder section (70) can also be an end section of a cartridge (100) protruding from the housing (2), which can be detachably arranged in the housing (2), but remains stationary with the housing (2) during operation of the spray device. Housing (2) and cartridge (100) can also be designed as a unit. A piston (101) is now designed to be displaceable within the hollow cylinder section (70). The piston (101) of the exemplary embodiment according to FIG. 4 represents a section of the valve body (102) which is opposite the hollow guide cylinder (48) is designed to be displaceable. The valve body (102) is essentially designed as an elongated hollow cylinder which in turn surrounds a hollow needle (103) which can be screwed firmly to the cartridge (100) or the housing (2) and which is open to the storage chamber (20). The hollow needle (103), also referred to as the hollow pin, is provided in the storage chamber with the seal (33), against which the displacement piston (23) can be placed at maximum stroke. The substance to be sprayed can now be pressed through the hollow pin (103) in order to flow via a radially extending opening (104) into the cavity (51) between the hollow guide cylinder (48) and the outside of the valve body (102). Depending on the pressure prevailing there, the valve head (55) then lifts off the valve seat (53). The opening (104) consequently represents the connection between the chamber (105) and the cavity (101), the former being delimited by the inner wall of the valve body (102) and the end face of the hollow pin (103).

The hollow guide cylinder (48) is in turn received by a hollow cylinder (73) which can be screwed onto the hollow housing section (70) and on which in turn the cup-shaped end section (83) of the valve device (4) and a further union nut (112) which acts as a compressed air regulator can be screwed.

Between the wall (106) facing the piston (101) of the hollow cylinder (73) receiving the guide hollow cylinder (48), which in turn is firmly connected to the hollow cylinder section (70) of the cartridge (100) or the housing (2), and the The end face (107) of the piston (103) on the valve side is now configured for the further working space (78), which can be connected to the compressed air connection (80) via the channel (79), in order to counter the piston (101) depending on the prevailing pressure to shift the force of the spring (76) and thus to lift the valve body (102) from the valve seat (53). From the working chamber (78) go out channels (107) and (109) which open into the air outlet channels (59). 4, the air outlet channels (59) for spraying the over Medium (58) emerging medium run between the pot-shaped end section (83) and a centering cap (110) which in turn receives the nozzle (8). Between the nozzle (58) and the valve seat (53) there is also a truncated cone-like seal (111), preferably made of a polymer.

By adjusting the regulating ring (112), the connection between the channels (108) and (109) can now be changed such that more or less compressed air is emitted via the air outlet channels (59).

The displacement of the valve body (102), which according to the invention forms a rigid unit with the piston (101) which can be displaced against the spring (76), which produces a force directed away from the housing (2), can be carried out exclusively and / or with compressed air .

FIG. 8 shows a preferred embodiment of the guide cylinder (48), which can also be referred to as a wear bushing, with the material nozzle (58) received by it. The material nozzle (58) can thus be inserted into the guide cylinder (48) from the housing side, centering being provided by projecting lugs (120) and (122). The material nozzle itself has a hard metal insert (124) which forms the actual nozzle and projects on the housing side over the holding body (125) receiving the nozzle with a flat surface (126). This surface (126) also serves as a valve seat for the valve head (127) on the end face of the valve body (102) or (30). An elastic element, which then acts as a valve head (55), can be embedded in the end face of the valve body (30), (102) in order to compensate for any canting. Appropriate construction enables a simple construction and thus easy maintenance of the valve head, the valve plates (53) described in connection with FIG. 2 being unnecessary. It is also not necessary for the valve head to be spherical, as shown in FIGS. 2 and 4. Rather, the valve seat (126) facing surface to be flat, as indicated in FIG. 6.

In Fig. 7, the check valve (5) is shown in an exploded view, which can be designed as a replaceable unit according to a further feature of the invention. The check valve (5) consists of a screw-in cage (174) in which a pressure spring (176) with a ceramic or hard metal sealing ball (178), valve seat (180) and sealing washer (182) is interchangeably arranged. If the check valve (5) wears out, the previously mentioned unit consisting of the elements (174) to (182) only has to be unscrewed from the housing in order to be replaced by a new one. This results in a high level of maintenance friendliness.

5 and 6 are particularly noteworthy embodiments of high-pressure dispensing guns (500) and (600) according to the invention, which work with or without compressed air (airless method). Otherwise, the construction of the high-pressure metering guns (500) and (600) is the same, so that the same reference numerals are used for the same elements.

A cartridge (504) is arranged in a stationary manner in a gun housing (502). A first cylindrical bush or bush (506) is screwed into the cartridge (504) and has a projection (508) which projects radially outwards. The front end (510) of the sleeve (506), that is to say of the hollow cylindrical body, has an inwardly directed radial section in order to receive a groove ring seal (512) between the first sleeve (506) and a hollow cylinder element (514). A so-called reversing valve body (518) is releasably clamped between the groove ring seal (512) and a radially inwardly extending section (516) of the cartridge body (504), which consists of a cylinder section (520) with valve ball sections (522) or (524) exists. The body (520) can be hollow. Spacer elements protrude from the outer surface of the body (520) in the direction of the inner surface of the first sleeve (504), in this way in this To ensure the position of the reversing valve body (518). These spacing elements are provided with the reference symbols (526) and (528) in FIG. 9. In a side view, the reversing valve body (518) has approximately a bone shape, the end regions (530) and (532) resting on the one hand on the groove ring seal (512) and on the other hand on the section (516) of the cartridge body (504). The cylindrical section (520) can clearly be completely flowed around by medium to be dispensed by the high-pressure dosing gun (500) or (600), such as polishing paste. This is conveyed from the housing (502) via the storage chamber (534) into the first working chamber (536) present between the reversing valve body (518) and the inner surface of the first bushing (506) by means of a compressed air motor (not shown, but already mentioned above).

The reversing valve body (518) is symmetrical both with respect to its main axis (538) and about its secondary axis (540) running perpendicularly to it. This has the advantage that when a valve head (522) or (524) is worn, the reversing valve body (518) only has to be turned over in order to align the valve head (524) or (522) that has not yet been used with the hollow cylinder (514) , which forms the valve seat (542) at the end. The hollow cylinder (514) is also symmetrical both with respect to its longitudinal axis (538) and its secondary axis, so that turning is possible.

The hollow cylinder (514) or the valve seat can consist of hard metal, ceramic, boron carbite or the like.

The first working chamber (536) is sealed on the one hand between the valve seat (542) and the adjacent valve head (522). On the other hand, the sealing takes place by means of the grooved ring (512) which is supported on the outer surface of the hollow cylinder (514).

The hollow cylinder (514) is now designed to be displaceable with respect to the first sleeve (504) so as to be dependent on the pressure prevailing in the first working chamber (536) Valve head to be spaced or to rest on this. For this purpose, a second bushing or bushing (544) is provided, which partially surrounds the first bushing (506) and is designed to be displaceable along this. The second bushing (544), that is to say the hollow cylindrical body, has a conically widening end region (546), in the interior of which a gasket (548), preferably made of nylon, can be inserted, which, for example, is press-fitted to the hollow cylinder (514). On the outside there is a nozzle (550) on the seal (548) through which the medium is sprayed. The nozzle (550) is gripped by a first union nut (552), which can be screwed onto the section (546) of the second sleeve (514) in such a way that the seal (548) in the conical extension of the internally conical section (546) the second sleeve (544) is clamped. As a result, the hollow cylinder (514) making the valve seats (542) or (554) available is determined at the same time.

The second bushing (544) has one or more leakage holes (572). These prevent that between the first and second bushing (506) and (544) in the area (574) of the hollow cylinder (514) by moving the second bushing (544) to the first negative or positive pressure that builds up can affect mutual mobility. Furthermore, medium emerging from the seal (544), which enters the space (574) along the outer surface, can escape through the leakage holes (572), so that medium cannot accumulate and thus cannot impair mobility. At the same time, if a medium escapes, it can be seen that the seal (512) and the hollow cylinder (514) must be revised.

The second bushing (544) can now be moved against the force of a spring (556) which is fixed between the second bushing (544) and a second union nut (558) which starts from the cartridge body (504). The force of the spring (556) is directed so that the second sleeve (544) is pressed towards the housing (502). In this way, a contact of the valve seat (542) on the valve head (522) of the stationary in the Cartridge body (504) and thus in the housing (502) arranged reversing valve body (518).

The end area of the second union nut (556) has a radially inwardly projecting section (560) which serves as a stop for the second sleeve (544).

The second bushing (544) is displaced and the valve seat (542) is lifted off the valve head (522) when the pressure prevailing in the first working chamber (536) overcomes the force caused by the spring element (556). In this case, the medium can flow through a channel (562) extending into the nozzle (550) so as to be sprayed.

In order to be able to turn or replace the wearing parts such as the reversing valve body (518) and the hollow cylinder (514) having the valve seats (542) or (554), it is only necessary that after loosening the first union nut (552) the second union nut (558) is removed so as to successively remove the second sleeve (544) and then the first sleeve (506) in order to subsequently replace or rotate the wearing parts.

The embodiment according to FIG. 6 differs from that of FIG. 5 in that the second bushing (544) and thus the valve seat (542) are lifted off from the valve body (518) with compressed air support, while simultaneously in the area of the nozzle ( 550) extending outlet channels (562) there is a mixing of the medium to be sprayed with compressed air.

For this purpose, a second working chamber (564) is provided, which is connected to a compressed air source, not shown.

The second working chamber (564) is laterally on the one hand from the radially outwardly extending section (508) of the first bushing (506) and on the other hand a radially outwardly extending section (566) of the second one running parallel thereto Limited sleeve (546), whose opposite wall serves as an abutment for the spring element (556). The second working chamber (564) is further delimited by a section of the inner wall of the union nut (558) and the outer surface of the first bushing (506) or a ring element (not specified).

If compressed air is applied to the working chamber (564), part of the force caused by the spring element (556) is overcome. This assists in lifting the valve seat (542) from the valve head (522). The compressed air then flows from the working chamber (564) through the space between the second sleeve (546) and the second union nut (558) to the outlet channels (562).

Claims (24)

1. A dosing gun (500,600), in particular a high-pressure dosing gun for spraying a medium such as polishing paste, having a cartridge element (504) held in a housing (502), a valve body (518) and a valve seat (542, 554) movable relative to one another against the force of a spring element (556) if an adequate pressure is generated by said medium in a first working chamber (536) between said valve seat (542) and said valve body (518), and a nozzle (550), preferably held by a cap nut (502), which is if necessary provided with or surrounded by outlet channels (562) for supplying compressed air,
   characterized in that
   said valve body (518) is mounted detachable for a first casing (506) forming a unit therewith, that said first casing extends from said cartridge element (504) or said housing (502), and that said valve seat (542, 554) is formed in the frontal part of a hollow cylinder (514) movable relative to said first casing, said hollow cylinder forming a unit with a second casing (544) movable against said spring element (556).
2. A dosing gun according to Claim 1,
   characterized in that
   the valve body (518) around which the medium can flow is supported against the first casing (506) by spacer elements (526, 528, 530, 532) which in their turn extend integrally from said valve body (518).
3. A dosing gun according to Claim 2,
   characterized in that
   the valve body (518) with the spacer elements (526, 528, 530, 532) is designed symmetrical with regard both to the main axis (538) and to the secondary axis (540).
4. A dosing gun according to Claim 1,
   characterized in that
   the hollow cylinder (514) holding the valve seat (542, 554) is designed symmetrical with regard both to the main axis and to the secondary axis.
5. A dosing gun according to at least one of the foregoing Claims,
   characterized in that
   between sections (508, 566) extending radially outwards of the first and second casings (506, 544), a second working chamber (564) is designed such that when acted upon by compressed air said second casing (544) is movable against the force of the spring element (556), with a connection existing between said working chamber and the outlet channels (562).
6. A dosing gun according to at least one of the foregoing Claims,
   characterized in that
   the first working chamber (536) is sealed preferably by a grooved ring (512) on the outside of the hollow cylinder (514).
7. A dosing gun according to at least one of the foregoing Claims,
   characterized in that
   a seal (548) preferably of plastic is arranged between the hollow cylinder (514) and the nozzle (550) and is supported on the second casing (544), and that the cap nut (552) holding said nozzle is screwable onto second casing (544) for fixing of said nut and of said seal.
8. A dosing gun according to at least one of the foregoing Claims,
   characterized in that
   the spring element (556) runs between the outside of the second casing (544) and a second cap nut (558) surrounding said casing in some areas and extending from the cartridge element (504) or the housing (502).
9. A dosing gun according to Claim 8,
   characterized in that
   the further cap nut (558) has a stop (560) limiting the movement of the second casing (544).
10. A dosing gun, in form of a high-pressure dosing gun for spraying a medium such as polishing paste, having a cartridge element (209) held in a housing (212), inside which housing a valve body (205) is arranged movable against the force of a spring element (211), where said valve body is at a distance from or in contact with a valve seat (222), and having a nozzle (202) held by a cap nut (201), where said nozzle (202) has a contact collar (220) in contact on the inside with the cap nut (201),
    characterized in that
    said nozzle (202) held by said cap nut (201) so as to be rotatable and axially movable against the force of said spring element (211).
11. A high-pressure dosing gun according to Claim 10,
    characterized in that
    a perforated disk element (203) containing the valve seat is in floating contact with the nozzle (202).
12. A high-pressure dosing gun according to Claim 11,
    characterized in that
    the cap nut (201) is fastened by a further cap nut (204) screwable onto the cartridge element (209), the front passage orifice of said cap nut (204) having at least in some areas a lower clear diameter than the perforated disk element (203).
13. A high-pressure dosing gun according to Claim 10,
    characterized in that
    the spring (211) acting on the valve body (205) is supported on the one hand against a first wall such as a cover (210) and on the other hand against a second, movable wall (208) such as a spring plate that can be brought into contact with the rear face (217) of the valve piston (205).
14. A high-pressure dosing gun according to Claim 10,
    characterized in that
    the valve body (205) is mounted movably in a valve piston guide (207) having a section (206) with a shoulder used as a stop (216) for the second wall (208).
15. A high-pressure dozing gun according to Claim 14,
    characterized in that
    the section (206) is designed as a replaceable wear bush.
16. A high-pressure dosing gun according to Claim 15,
    characterized in that
    the valve body (205) is designed as a hollow element carrying the medium in whose walls a continuous seal (214) is provided to seal against the wear bush (206).
17. A dosing gun (1), in particular a high-pressure dosing gun for spraying a medium such as polishing paste, having a cartridge element (18, 100) extending from a housing (2), a valve body (30, 102) and an associated valve seat (54) movable relative to one another against the force of a spring element (42, 76) if an adequate pressure is generated by said medium in a first working chamber (51) between said valve seat and said valve body, and a nozzle (58, 111), preferably held by a cap nut (56, 83), which is if necessary connected to or surrounded by outlet channels (59) for supplying compressed air,
    characterized in that
    said valve body (30, 102) is surrounded at least in some areas by a hollow guide cylinder (48), that said valve body and said hollow guide cylinder are movable relative to one another, that a valve element (53) containing said valve seat (54) is fixed between said hollow guide cylinder and said nozzle (58, 111), and that between said hollow guide cylinder or an element connected thereto and an element (18, 75) holding said valve body or extending therefrom is arranged a further working chamber (45, 78) that can be subjected to compressed air for movability of said valve body relative to said valve element (53), said further working chamber being connected to the outlet channels (59).
18. A dosing gun according to claim 17,
    characterized in that
    the valve body is designed as a hollow needle (30) having a radially curved outlet channel at its end section (35) projecting into the first working chamber (51), and that the end of said hollow needle (30) in said first working chamber (51) supports a valve head.
19. A dosing gun (1), in particular a high-pressure dosing gun for spraying a medium such as polishing paste, having a cartridge element (18, 100) extending from a housing (2), a valve body (30, 102) and an associated valve seat (54) movable relative to one another against the force of a spring element (42, 76) if an adequate pressure is generated by said medium in a first working chamber (51) between said valve seat and said valve body, and a nozzle (58, 111), preferably held by a cap nut (56, 83), which is if necessary connected to or surrounded by outlet channels (59) for supplying compressed air,
    characterized in that
    said valve body (30, 102) merges into a section such as a piston (101) extending radially outwards that on one side limits the further working chamber (78) and on the opposite side is acted upon by the spring element (76 ) with a force directed away from the housing (2).
20. A dosing gun according to Claim 19,
    characterized in that
    the valve body (102) surrounds a hollow cylinder (103) in axially movable manner, said cylinder being connected to the housing (2) or cartridge element (100) and being passable by the medium to be sprayed by said dosing gun.
21. A dosing gun according to one of the previous Claims,
    characterized in that
    the nozzle (58) is mounted preferably by the hollow guide cylinder (48) and has has an insert (124) of carbide forming the valve outlet orifice on the outside and the valve seat (126) on the inside.
22. A dosing gun according to Claim 21,
    characterized in that
    the valve seat (126) is flat in design, with which a flat front face or a flat or if necessary elastic replaceable end piece (127) of the valve body (30, 102) can make contact.
23. A dosing gun according to one of the previous Claims,
    characterized in that
    a check valve (5) is provided in a line carrying the medium, said valve comprising as a replaceable unit a screw-in cage (174) with contact spring (176) provided therein, valve ball (168), valve seat (180) and sealing disc (182).
24. A dosing gun according to at least one of the previous Claims,
    characterized in that
    the seal (49) of the first working chamber (51) containing the medium is provided on the one hand by the valve seat (54) and on the other hand by a seal running between the valve body (30, 102) and the hollow guide cylinder (48).

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