EP0047488A2 - Safety-backflash coating apparatus - Google Patents

Abstract

1. An application apparatus, which is protected against flashback, for applying metallic coating material on to metallic support surfaces to be coated, with an apparatus housing (3) which has feed passages (4, 4', 6) for first and second combustible gas components and the material to be applied, with an intermediate member (5) which has feed passages (8, 8', 6) extending to a nozzle connection side for the two combustible gas components and the material to be applied, and with a nozzle which comprises a central part (13) with a passage (17) for the first combustible gas component and with a passage (15) for the second combustible gas component and with a retaining part (14), an annular clearance (19) being formed between the central part (13) and the retaining part (14), characterised in that the intermediate member (5) has individual transverse passages (11, 11') closed gas-tightly from the outside, into which discharge respective axial feed passages (8", 8'") originating from the apparatus connection surface (2) and from which respectively at least one of the axial feed passages (8, 8') is continued to the nozzle (1), in that the combustible gas components are mixed in the nozzle (1) in an annular groove (20), in that in the nozzle (1) one axial feed passage (8) is connected via the passage (17) for the first combustible gas component and via the annular clearance (19) with the annular groove (20) which is spaced apart from the nozzle connection side, in that relative to the front surface (27) of the nozzle (1) the annular clearance (19) is sealed by substantially cylindrical peripheral surfaces of the central part (13) and retaining part (14) which are adjacent to one another in this zone (22), and in that in the nozzle (1) the other axial feed passage (8') is connected with the annular groove (20) via the passage (15) for the second combustible gas component.

Description

The invention relates to a reignition-proof applicator for applying metallic application material to metallic carrier surfaces to be coated according to the preamble of the main claim.

Applicators of the type mentioned have been known recently and have been used in particular for powder flame spraying, the re-ignition security being ensured by a special nozzle design. In contrast to previous nozzles on such devices, the gas components are no longer mixed in an ignitable and thus explosive mixture at a suitable location in the device, but in the nozzle itself, practically only immediately before the orifices at the nozzle.

Such "internally mixing" nozzles were known per se from cutting torches, in which, however, the requirement of safety against reignition was not as much in the foreground as is the case with devices for the application of metallic layers, which was already the case with this has led to a wide variety of solutions, but ultimately could not fully satisfy.

The assignment of such re-ignition-proof, internally mixing nozzles to devices of a known type, although absolutely desirable, is now not readily possible for such application devices, unless a device that is suitable and suitable for the nozzle is developed in the opposite sense, as is practically the case with the device of the type mentioned at the beginning.

It should be taken into account here that, in contrast to simple welding or cutting torches in application devices of the type of interest here, the powder and carrier gas supply, mixture of these Components, seals of metallic connection surfaces etc. must be worn when accommodating in a confined space

To make matters worse, the gas component supply lines, or their outlets on the device generally do not match the corresponding connection openings of the internally mixing nozzle, ie, a connection of the nozzle to the device housing, which is usually pistol-shaped, is in a certain sense an "asymmetry" of the connection conditions.

In the device of the type mentioned at the outset, which has become known in recent times, this has in no way been solved in an optimal way by providing a block which is incorporated and permanently arranged in the device itself, the gas components being passed on to the nozzle connection surface by means of small gas line tubes. The nozzle must be clamped very tightly and tightly against the metallic connection surface of the block for proper operation of the device. The nozzle replacement that is often required in coating processes is disadvantageous in that the entire device (such devices generally have clamping surfaces running parallel to almost no point) has to be clamped in a vice or other holder in order to loosen the union nut holding the nozzle, the nozzle to be able to replace and tighten again.

In addition to the necessary and cumbersome clamping of the entire device, there is also a risk of damage to the metallic sealing surface in addition to the possible external damage to the device housing, possibly also due to small powder particles that have remained unnoticed, which can lead to repeated installation and removal of the nozzle.

It should also be taken into account that, depending on the design of such devices, the arrangement of thermally limited loadable sealants (e.g. soft ring seals) is unavoidable at various points, possibly due to the special type of channel routing and channel division into several evenly distributed individual transmission channels.

The direct arrangement on the block included in the device housing in the known device, which, however, does not require such seals due to the forwarding tubes, could not be indicative of such constructions in which such seals have to be used, apart from the fact that the entire device is of course in the connection area the nozzle becomes relatively hot up to the connection of the powder storage vessel, since the nozzle getting hot is connected directly to the block that is firmly integrated in the device housing.

The invention is therefore based on the object to improve the device of the type mentioned in such a way that on the one hand, the re-ignition-proof nozzle can be replaced more easily and without damage, without having to clamp the entire device housing, and a new nozzle can accordingly be easily tightened again, specifically under Protection of the metallic sealing surface and that furthermore thermally limited resilient sealing rings can be used with the requirement of the greatest possible distance from the hot burner head, and that on the other hand the possibility is created to be able to connect the advantageous re-ignition-proof, "internally mixing nozzle to the device housing, too if the connection mouths of the nozzle do not match the mouths on the device housing.

This complex task is accomplished with a device of the type mentioned according to the invention solved in the characterizing part of the main claim. Advantageous further developments result from the subclaims.

It is therefore essential in this solution according to the invention that neither the nozzle in its basic peculiarity nor the device in its special peculiarity is matched constructively to one another by specific adaptation in one and / or other direction, but another way in the form of the formation of a special intermediate piece has taken into account, with which the other factors that are essential and important for such a device, namely easy interchangeability, "thermal distancing" of the nozzle from the actual device housing and usability of seals with limited thermal stress, are taken into account.

Since, according to the invention, the intermediate piece is designed to rest against the connection surface of the device housing or to be easily insertable (for example with a sealed plug-in design), So the whole nozzle adapter unit can be removed and the nozzle can be advantageously replaced on the removed adapter and used again with this, which leads to a significant ease of use, apart from the possibility of having a finished set of several intermediate pieces with nozzles already attached to them can, so that only the respective adapter with nozzle must be replaced with another adapter with nozzle.

Through the use of the re-ignition-proof, "internal mixing" nozzle, in which there is only an extremely small volume of an ignitable and explosive gas mixture within a very short distance within the nozzle, you can also use sealing rings with a limited thermal load on the adapter these are advantageously arranged as far as possible in the end region of the intermediate piece remote from the nozzle.

The design and arrangement of the intermediate piece according to the invention even makes it possible without changing the intermediate piece in principle - since this only has a transfer function but no mixing function for the gas components - the channels (application material supply channel and gas component channels) in the form of tubes with corresponding diameters form between the contact surface sections to be retained.

This means that even larger "thermal spacings" are easily possible. angled nozzle arrangements possible.

The application device according to the invention and its advantageous embodiments and training forms are explained in more detail below with reference to the drawing of exemplary embodiments.

• Fig. 1 einen Schnitt durch den Kopf des Auftragsgerätes;
• Fig. 2 eine Ansicht der geräteseitigen Anschlußfläche;
• Fig. 3 eine Ansicht der düsenseitigen Anschlußfläche;
• Fig. 4 einen Schnitt längs Linie IV-IV durch das Zwischenstück;
• Fig. 5 einen Schnitt längs Linie U-U durch das Zwischenstück;
• Fig. 6 teilweise in Schnitt und Ansicht eine besondere Ausführungsform des Zwischenstückes;
• Fig. 7 einen Längsschnitt durch das Zwischenstück;
• Fig. 8 einen Querschnitt längs Linie A-A in Fig. 7;
• Fig. 9 einen Querschnitt längs Linie B-B in Fig. 7;
• Fig. lo einen Querschnitt im Sinne der Fig. 8;
• Fig. 11 einen Querschnitt im Sinne der Fig. 9 aber in anderer Ausführungsform;
• Fig. 12 in perspektivischer Ansicht das Zwischenstück mit Abdeckschalen;
• Fig. 13 im Schnitt eine besondere Ausführungsform und
• Fig. 14 im Schnitt eine besondere Ausführungsform der geräteseitigen Abdeckhülse.

It show schematically

• 1 shows a section through the head of the applicator.
• Fig. 2 is a view of the device-side pad;
• 3 is a view of the connection surface on the nozzle side;
• Figure 4 is a section along line IV-IV through the intermediate piece.
• 5 shows a section along line UU through the intermediate piece.
• 6 shows a special embodiment of the intermediate piece, partly in section and view;
• 7 shows a longitudinal section through the intermediate piece;
• 8 shows a cross section along line AA in FIG. 7;
• FIG. 9 shows a cross section along line BB in FIG. 7;
• Fig. Lo is a cross section in the sense of Fig. 8;
• 11 shows a cross section in the sense of FIG. 9 but in another embodiment;
• 12 is a perspective view of the intermediate piece with cover shells;
• Fig. 13 in section a special embodiment and
• Fig. 14 in section a special embodiment of the device-side cover sleeve.

The term powder flame spraying device used in the following exemplary embodiment is not intended to exclude that the application material can also be supplied in another form (for example as a wire). Furthermore, the term flame spraying is also not intended to express any restriction to this special type of application.

In Fig. 1 the entire head of a powder flame spraying device is shown approximately on a scale of 2: 1. From the device, only the connection area can be seen, to which the entire, approximately pistol-like device housing 3 connects to the right.

Symmetrically to the central powder carrier gas channel 6, that is to say, for example, lying on a common circle, the supply channels 4, 4 'feed the gas components for the flame formation in front of the nozzle, i. H. through the lines 4 the fuel gas and through the line 4 'the oxygen, the intermediate piece 5 in the connection surface 2 having correspondingly aligned supply channels 8 ", 8"' leading to gas component distributor grooves 11, 11 'lying in the connection area 24 , from which, running in concentric circles (seen in section), for example, lead several supply channels 8,8 'to the nozzle connection side and open there in two concentric ring channels 25,25'.

However, the division into several individual channels 8,8 'is not absolutely necessary, that is, it can also in each case only one channel satisfy 8.8 ¹ in the sense of Fig. 1.

Due to this channel routing, no gas mixture takes place in the intermediate piece. Functionally, the intermediate piece 5 only has the following tasks: continuation of the separately held gas components to the nozzle; Moving the gas components of, for example, supply ducts 4,4 'or 8 ", 8"' lying on a common circle on two ring ducts 25, 25 'of different diameters; if necessary, by dividing it into several supply channels 8, 8 ', evenly distributed over the circumference, even distribution of the gas components in the area of the intermediate piece; Support function for the nozzle 1 placed at the front, which is therefore only to be clamped on the intermediate piece 5 and can be replaced on and with this and finally a thermal distance function for the nozzle 1 to the device housing 3.

The inner-mixing nozzle 1, which can be seen on the left in FIG. 1, consists of a central part 13 and a coupling part 14, both of which have flanges 16, 18 that match one another.

The channels 15 'continuing the supply channels 8' run in the central part 13 and the channels 17 continuing the supply channels 8 only in the flange 16 of the central part 13.

The coupling part 14 forms from an annular groove 2 ₀ to the intermediate piece 5 towards the central part 13 an annular gap 19 which is expanded in the region of the two flanges 16, 18 and thus also covers the channels 17, so that the gas component supplied through the channels 17 can continue to flow through the annular gap 19 to the annular groove 2a, but into which, as can be seen, the channels 15 also open.

It is only at this point that the two gas components are mixed shortly before the nozzle front surface 27, which means that there is an extremely small gas volume from a re-ignitable gas mixture from the front surface 27 to the device over a very short distance. The short sealing surface in the surrounding area 22 in front of the annular groove 20 is advantageously kept slightly conical.

The entire nozzle 1 from the central part 13 with flange 16 and coupling part 14 with flange 18 is, as shown, clamped with a coupling piece 23 on the intermediate piece 5, while this whole unit formed from nozzle 1 and intermediate piece 5 by means of a holding element lo in the form of a Union sleeve is attached to the device housing 3, for which a tightening by hand is sufficient. For the precise assignment of the channels 8 ", 8"'in the intermediate piece 5 to the channels 4, 4 ¹ in the device housing, the arrangement of any alignment elements in the area of the connection surface 2 is sufficient.

The representations in FIGS. 2 to 5 clarify the arrangement and breakdown of the individual channels and do not require any further explanation in view of the corresponding reference numerals given. According to FIG. 6, the intermediate piece 5 "'can also be formed from two partial pieces 5', 5", these being connected to one another by pipes 12, 12 ', 12 "corresponding to the feed channels and the application material feed channel.

The arrangement of distributor grooves 11, 11 ', as shown, is not absolutely necessary here, since the compensation of the connection asymmetry can also be carried out by the tubes 12', 12 "themselves.

Since the seals 28, as can be seen, are located relatively far from the nozzle 1 becoming hot and, moreover, because of the nozzle there are no internal ignitions to be feared in the entire burner, special cooling of the entire device stem can be saved. Irrespective of this, however, an air purging of the interior between the union sleeve 10 and the rear end of the intermediate piece 5 would be possible without any problems, for which purpose corresponding blow-out openings 3o must be provided.

Nozzle lo could also, as indicated by dashed lines in FIG. 1 in the upper half, be extended to the front and engage a holding piece 29 provided with bores.

On the intermediate piece 5, attachment surfaces 26 are advantageously provided for the attachment of a wrench or clamping jaws, in order to attach the intermediate piece 5 in the event of a nozzle replacement, which requires the loosening of the clamped union piece 23 to be able to hold better.

The embodiments according to FIGS. 7-14 represent particularly advantageous embodiments with regard to the sealing of the transverse channels 11, 11 ', as a result of which molded ring seals are not necessary at all.

In contrast to the previous solution described, this is done by two pushed-on cover sleeves 31, which are sealed gas-tight along their edges 32 with the metallic body of the intermediate piece 5, which is best done by means of soldered seams.

Since the transverse channels 11, 11 ', as can be seen from FIG. 8.9, cover almost the entire cross section of the intermediate piece, except for material webs 33 that remain, for the passage of the other channels, several channels 8, 8' could be evenly distributed over the circumference arranged and guided to the ring channels 25, 25 ¹ .

In the exemplary embodiment according to FIGS. 10, 11, the transverse channels 11, 11 'are simply created in the form of bores 34, 34', each with a further outer gradation in diameter, into which a metallic plug 35 is then inserted for closure and this is soldered gas-tight in the area of its exposed top surface. Of course, one could also create the bores 34, 34 'as threaded bores, screw in a grub screw and close them in a gas-tight manner.

In particular, if the transverse channels 11, 11 'are only, for example, arcuate (see dashed line 35 in FIG. 8), it is not absolutely necessary to arrange cover sleeves 31, but small cover shells 36 (see FIG. 12) are sufficient, which are also longitudinal the edges 32 are soldered.

If the connection of the intermediate piece 5 to the device (all connection and holding elements, such as Union sleeves or the like, are not shown) does not allow a projecting arrangement of sleeves 31 or shells 36, a flat and wide annular groove 37 can, of course, be cut into the metallic body in the sense of FIG. 13, into which the then divided sleeves can be cut 31 or insert the trays 36 flush to the outside. The width of the annular groove 37 should be such that there is still sufficient space for the soldered seams, which are also to be kept flush. In the case of the arrangement of shells 36, the groove 37 would of course not have to be formed all the way round, but the arrangement of a circumferential annular groove 37 should be given preference for manufacturing reasons (simple turning).

Since the sleeves 31 have a relatively thin wall thickness and, due to the separation, a certain spring property, the sleeves can be pushed over the intermediate piece and snap into the annular groove 37. The annular groove 37 can, however, if the other design conditions allow, run out towards one end or the other of the intermediate piece 5 (strictly speaking, there is no annular groove, but an external gradation of the metallic body), so that the self-contained ones Sleeves can be pushed onto the outer gradation.

Possibly. one could even provide the device-side sleeve 31 with an annular flange 31 ¹ , which can then simultaneously serve as a holding flange for a screw-on sleeve 3 onto the union sleeve, which advantageously means that the intermediate piece 5 would no longer have to be twisted to form a holding flange.

Claims (10)

1.Reignition-proof application device for applying metallic application material to metallic carrier surfaces to be coated, consisting of a device housing with supply channels for the fuel gas components and with an application material supply channel, which channels lead to an exchangeable nozzle on the device head and the supply channels of the gas components which continue in the nozzle for the purpose of mixing them in the nozzle, characterized in that between the internal mixing nozzle (1) and the connection surface (2) of the device housing (3) an adapter (5) which is adjacent to the connection surface (2) or is easily insertable, with corresponding transmission channels or supply lines - And supply channels (6,8,8 ') is arranged, which are separated from each other in the intermediate piece (5) running forwarding channels connect the connection openings of the nozzle connection side (7) with the corresponding connection openings of the connection surface (2) of the device housing (3) and furthermore the nozzle (1) and the intermediate piece (5) are fastened to the device housing (3) with holding elements (lo) . 2.Device according to claim 1, characterized in that in the intermediate piece (5) arranged with the connection openings in the connection surface (2) of the device housing (3) aligned supply lines (8 ", 8" ') to separate and shielded from the outside Gas component distributor grooves (11, 11 ') and from these at least one individual channel (8, 8'), which is also separated with respect to the gas components and is arranged to the corresponding connection openings of the nozzle (1). 3. Apparatus according to claim 1 and / or 2, characterized in that the intermediate piece (5) in two partial pieces (5 ', 5 ") separately and these through, the supply channels and the application material supply channel corresponding pipes (12, 12' , 122 '), are interconnected. 4. Device according to one of claims 1 to 3, characterized in that the coupling part (14) and the central part (13) of the internal mixing nozzle (1) with their flanges (16, 18) lying together by means of a coupling piece (23) on the intermediate piece ( 5) releasably attached and this unit consisting of nozzle (1) and intermediate piece (5) is releasably attached to the device housing (3) by means of a union sleeve (lo). 5. Apparatus according to claim 2, characterized in that the gas component distributor grooves (11,11 ') in the device connection side area (24) of the intermediate piece (5) are arranged. 6. Apparatus according to claim 1, characterized in that the transverse channels (11, 11 ') of the intermediate piece (5) are each closed by a cover sleeve (31) or cover shell (36) and the sleeves (31) or cover shells (36) are sealed gas-tight along their edges (32) with the metallic body of the intermediate piece (5). 7. Apparatus according to claim 1, characterized in that the transverse channels (11, 11 ') are designed as bores (34, 34') and in their respective outer ends a plug (35) is arranged and the accessible end of the plug with the metallic body the intermediate piece (5) is closed gas-tight. 8. Apparatus according to claim 6, characterized in that in the region of the transverse channels (11, 11 ') on the outside of the intermediate piece (5) a sleeve (31) or the shells (36) is arranged flush receiving groove (37). 9. Apparatus according to claim 6 and / or 8,
characterized in that the cover sleeve (31) arranged on the device side is provided with an annular flange (31 '). lo. Intermediate piece according to claim 7, characterized in that the bores (34, 34 ') are provided with a stepped plug receptacle (34 ").

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