US3856282A

US3856282A - Device for applying flame-scarfing powder

Info

Publication number: US3856282A
Application number: US00407273A
Authority: US
Inventors: A Lucht
Original assignee: Messer Griesheim GmbH
Current assignee: Messer Griesheim GmbH
Priority date: 1972-10-21
Filing date: 1973-10-17
Publication date: 1974-12-24
Anticipated expiration: 1991-12-24
Also published as: ATA812573A; SE382932B; DE2251788C3; FR2204131A5; DE2251788B2; GB1433187A; JPS5315697B2; DE2251788A1; JPS4974148A; AT328826B; IT994465B

Abstract

A device for applying flame-spraying powder to the top and side surfaces of work pieces to be flame scarfed is characterized by a powder supply conduit having at least two branches, one of which terminates at the center of the chamber of the device and the other of which terminates at the frontal side of the chamber. The outlet consists of a plurality of side by side channels connected by means of conduits to the chamber.

Description

United States Patent 1 Lucht Dec. 24, 1974 DEVICE FOR APPLYING FLAME-SCARFING POWDER [75] Inventor: Alfred Lucht, Bickenbach, Germany [73] Assignee: Messer Griesheim GmbH, Frankfurt/Main, Germany [22] Filed: Oct. 17, 1973 [21] Appl. No.: 407,273

30 Foreign Application Priority Data Oct. 21, 1972 Germany 2251788 [52] US. Cl. 266/23 H, 148/9, 266/23 S [51] Int. Cl B23k 7/08 [58] Field of Search 239/85, 430; 266/23 P,

266/23 H, 23R, 23 S, 23 T; 148/96, 9.5

[56] References Cited UNITED STATES PATENTS Fleming, Jr 266/23 S 2,873,224 2/1959 Thompson et al. 266/23 H X 3,224,748 12/1965 Buddenhagen 266/23 H 3,230,117 1/1966 Buddenhagen 266/23 H X Primary Examiner-Granville Y. Custer, Jr. Assistant Examiner-Paul A. Bell Attorney, Agent, or Firm -Connolly and Hutz [5 7 ABSTRACT A device for applying flame-spraying powder to the top and side surfaces of work pieces to be flame scarfed is characterized by a powder supply conduit having at least two branches, one of which terminates at the center of the chamber of the device and the other of which terminates at the frontal side of the chamber. The outlet consists of a plurality of side by side channels connected by means of conduits to the chamber.

11 Claims, 4 Drawing Figures PATENTED 9552 41974 sum 1 0F 3 DEVICE FOR APPLYING FLAME-SCARFIN POWDER BACKGROUND OF THE INVENTION The invention relates to a device for applying flamespraying powder, particularly iron dust, to the top and side surfaces of the work pieces to be flame scarfed with a conduit for supplying the powder from a storage container into a chamber of the device and with a discharge conduit connected with the chamber, the powder being supplied to the work piece surface through said discharge conduit with the help of a flow medium.

Devices of the above-stated kind are already known (German Pat. No. 1,198,282). In these devices, the powder is conducted to the chamber by means of a conduit in such a manner that the powder accumulating in this chamber forms a cone of loose material whose tapering point protrudes into the outlet, so that the air flowing there pulls the powder with it. Since the powder automatically glides through the conduit by the force of gravity, in this manner powder always reaches the outlet.

It is, however, disadvantageous in these known devices that the powder runs into the outlet even during an interruption of the conveying air current, which is caused by the vibrations resulting during the movement of the flame cutting or flame scarfing machine associated with the device. Consequently, there is the danger that powder would constantly run out of the device onto the work piece surface. Alternatively, powder would settle at some spot of the outlet and clog it, so that for the next powder requirement, a plug of the accumulated powder would first be ejected by the conveying air. On the other hand, it is also possible that due to the moisture in the air the powder would stick together or agglomerate and this agglomeration could no longer be driven out from the outlet by the conveying air pressure, thus requiring a time-consuming cleaning of the device.

Such a device is therefore not suitable for selective flame scarfing where it is important to supply iron dust discontinuously to the individual faulty areas on the surface of the work piece to be processed in order to facilitate the flame scarfing start.

SUMMARY OF THE INVENTION The object of the present invention, therefore, is to provide, emanating from the state of the art, a device for the application of powder, particularly iron dust, by means of which not only the top surface of a work piece to be processed may be provided with iron dust but also by means of which the powder may be applied to the vertical side surfaces of the work piece, and in addition with each interruption of powder supply it is assured that powder does not reach the work piece unintentionally or is not deposited in the outlet.

For solving the stated problem, according to the invention, the powder supply conduit has at least a twopart construction of which one branch ends in the center of the chamber and the other branch is connected with the frontal side of the chamber, and that the outlet consists of numerous channels, arranged side by side, which are connected with the chamber by means of conduits.

By the dual supply of the powder it is assured that, with a turning of the flame-scarfing torch carrying the device, about an axis proceeding in the direction of the flame scarfing, for the purpose of flame scarfing the side surfaces, iron dust is supplied in a sufficient measure to the outlet channels. This is important even then when the device is swung so that the longitudinal or horizontal axis of the chamber then becomes vertical.

By the novel arrangement of additional connecting conduits between the chamber and the outlet channels, it is assured that with the interruption of the conveying current (e.g. compressed air), no powder reaches into the outlet channels and instead the loose cone forming in the connecting conduits ends with its tip at a safe distance from the outlet of the connecting conduit into the respective outlet channel.

According to the invention, it is advantageous furthermore if the branch conduits at their one end have connection pipes firmly connected with the chamber. For a uniform supply and filling of the chamber with iron dust, it is furthermore advantageous for the connection pipes to be aligned parallel to each other.

It is then particularly advantageous here if the longitudinal axis of each connection pipe and the longitudinal axis of the chamber form an angle of 3075 and preferably 60.

In accordance with a further novel suggestion the powder supply conduit is provided for the conveying of an additional medium transporting the powder. This supplemental conveying medium current assures a uniform supply of the powder from the chamber and by way of the connecting conduits into the appropriate outlet channel. The quantity of the powder supplied into the outlet channels may also be controlled to a certain extent by a change in pressure of the supplemental conveying'medium current. With an interruption of the powder supply, preferably the supplemental conveying current being first turned off and then the main conveying current, there is formed as mentioned above a loose cone in the connecting conduits which ends at a safe distance from the particular outlet channel. With a renewed powder conveyance, the loose cone is then easily dissipated by the additional conveying medium as well as by the main conveying current producing an underpressure or vacuum in the connecting conduits, and the powder reaches, in the form of a powder-conveying-medium mixture, the work piece by way of the outlet channels. The danger of the stopper formation of the powder during an interruption is consequently prevented.

Finally, in accordance with a further ramification of the novel device a flame-scarfing torch is turnable about an axis proceeding in the direction of flame scarfing the two-part powder supply conduit is arranged between the storage container and the device in such a manner that a constant flow of powder is afforded independent of the tilt position of the flamescarfing torch. This is achieved in that the storage container is arranged on the machine essentially vertically or perpendicular above the device. By the turning of the device subject to the flame-scarfing torch carrying it both branch conduits are moved in accordance with the turning movement; the two branch conduits preferably being made like flexible hoses and for the sake of expediency having rigid connecting pieces firmly connected with the device or with the device container; in'this connection, however, independent of the particular turningor swinging of the device, the hoses have an incline which is greated than the angle of repose of the powder to be conveyed, so that a constant flow of powder is afforded.

THE DRAWINGS FIG. 1 is a side view of the novel device in cross-section; I

FIG. 2 is a sectional view along line AB in FIG. 1;

FIG. 3 is an enlarged illustration of the connection between chamber and outlet channel; and

FIG. 4 is a schematic arrangement of the device with reference to a powder container.

DETAILED DESCRIPTION In FIG. 1 is illustrated a novel device for the supplying of iron dust (flame-scarfing powder) onto the surface of a work piece, e.g. an iron slab. The device, described below as a powder harp, is mounted on the top side of a flame-scarfing torch 14 by means of screws 12, of which only one is shown.

Powder harp 10 consists of a main block 16 on which is firmly attached by means of screws 20 a front block 18 pointing in the direction of flame spraying.

In the main block 16 see FIG. 2 there is provided a cylindrical chamber 22, which extends essentially over the entire length of the block. Longitudinal axis 24 of chamber 22 proceeds horizontally in the normal position of the powder harp.

Chamber 22, in accordance with the invention, is in contact with two connecting

pipes

26, 28. These connecting pipes are firmly inserted into the main block I6, e.g. by welding or bolting, and with their free ends are connected with flexible hoses or

metal hoses

30, 32. These flexible hoses form the branch conduits of a powder supply conduit, designated as a whole with 34. Both supply conduits 30, 32 of the supply conduit 34 end in a distributing piece 36 (FIG. 4) which in turn ends in the bottom of a storage container 38.

As further shown in FIG. 2, both connecting

pipes

26, 28 are arranged parallel to each other and furthermore shown to be opposite chamber 22. The longitudinal axis 40 of each connecting pipe 26, 28'intersects in this connection the longitudinal axis 24 of the chamber at a certain angle. This angle preferably is between and 75, and in exemplary embodiment is 60.

Chamber 22 has numerous connecting conduits 42, arranged side by side, which distributed over the broadside, extend through the main block 16.Each connecting conduit ends in a respective outlet channel 44,.

which, beginning in themain block, extends through the front block 18.

As shown in-FIG. l, the numerous outlet channels, which in the normal position of the powder harp 10 are directed downwards at an incline, end in a chamber 46, which in turn terminates in an outlet slot 48 extending over the entire breadth of the powder harp. In place of chamber 46 and slot 48, it is of course possible and is within the frame of the invention to provide individual outlet bores forming the continuation of each outlet channel 44.

As further shown in FIG. 1, the upper end of each outlet channel 44 is in contact by means of channels 50 and a storage chamber 52 with a conveying medium conduit 54 from which the conveying medium, usually compressed air,is supplied to the outlet channels. The compressed air, in accordance with the exemplary embodiment, is introduced into the outlet channel 44 by means of a nozzle 56, so that in the terminal area of each connecting conduit 42 in channel 44, an optimum negative or underpressure or suction is thereby obtained. Of course, it is also possible to introduce the conveying medium from channel 50 directly into the outlet channel 44 hence without a nozzle.

By means of a further conduit 58, illustrated by dotted lines, purifying air is supplied to the powderharp. The purifying air reaches slot 48 in the direct proximity of the outlet end of the slot and serves during a pause in operations to free the powder harp of any still adhering powder residues.

For cooling the powder harp, said harp is equipped with a cooling channel system 60, which is shown in FIG. 1 in a simplified manner. Air, water or another coolant may be used as the cooling agent.

As shown in FIG. 4, storage container 38 is connected with a main storage container 64 by means of conduit 62. In this connection, depending on the conveying height h, in container 64 such a pressure prevails (e.g. 3-6 atmospheric super pressure), which is sufficient to transport the powder without interference through conduit 62 into storage container 38. In order to prevent the formation of a pressure (3-6 at. super press), corresponding to that of the main storage container, in the storage container 38 which is preferably located above the powder harp, container 38 is equipped with a pressure escape valve 66 adjusted so that only a pressure of ca. 1 at. sup. press. is maintained in container 38.

,As mentioned above, the novel device is arranged on the top side of a flame-scarflng torch 14 and serves to supply iron dust to the spot to be flame scarfed at the beginning of the flame-scarfing process in order to shorten thereby the heating up time during which time the spot of the work piece to be flame scarfed is heated to ignition temperature by the preheating flame.

The iron dust, shortening the preheating time, reaches chamber 22 of the powder harp from the storage container 38 by the force of gravity and supported by the overpressure (ca. 1 atmosphere) prevailing there by means of the two-part conduit 34. At the powder harp, the powder is drawn into conduits 42, subject to the underpressure prevailing in the connecting conduits 42, this underpressure being caused by the conveying medium (compressed air) flowing through the outlet channels 44. From conduits 42, the powder then reaches the outlet channels and is there taken along by the compressed air to the outlet slot 48 in the form of a powder-air mixture. This suction effect of the compressed air on the powder in the connecting conduits 42 is supported by the superpressure present in container 38 and continuing into chamber 22, the iron dust being pushed into the connecting conduits 42 by this superpressure.

When iron dust is no longer required, the compressed air (conduit 54) in a given instance and also the air of the

storage system

38, 62, 64, acting as the supplemental conveying medium, are all turned off. Because of the presence of the connecting conduit 42 between chamber 22 and the particular outlet channel 44, it is advantageously prevented that upon turning off, the powder does not travel from chamber 22 into the outlet channels 44-and from there on the work piece. In the connecting conduits 42, only a loose cone 66 is built up whose tip 68 is disposed by a certain distance S (which may be considered a safety zone) from the termination of the connecting. conduit into the "channel 44. This safety zone S is sufficient to prevent the powder from falling into the outlet channels during operation, e.g. generated vibrations. Furthermore, it is advantageously possible to raise the connecting conduits in the direction toward the outlet channels 44 in order to put up a further opposition thereby to a possible, undesired movement of powder.

With the aid of the novel powder harp, it is not only possible as stated above to provide the (horizontal) surface of a work piece, e.g. an iron slab, with powder for the purpose of shortening the preheating time but the powder harp is also suitable, according to the invention, for the application of powder to the (vertical) side surfaces of the work piece.

For this purpose, the powder harp is provided'on the laterally arranged flame-scarfing torch of a flamescarfing machine whose outlet slot proceeds parallel, hence vertical to the side surface to be flame scarfed. Such a machine is disclosed in U.S. Pat. No. 2,295,523, for example. On the other hand, it is also possible, and it is mentioned below, to mount the powder harp on a flame-scarfing torch rotating about an axis pointing in the direction of flame scarting. Such a turnable flame scarfing torch is disclosed in DOS 1,947,284.

When the flame-scarfing torch is then turned about the axis pointing in the direction of flame spraying, the powder harp carried by the torch is equally turned as indicated in FIG. 4 by dotted lines. According to FIG. 2, the rotation of the powder harp takes place at a point of rotation M in a counterclockwise manner. By the use of

flexible hoses

30, 32, it is made certain that the powder may flow into chamber 22 from storage container 38 in any position of the powder harp, since the hoses always have such an incline (pitch) which is greater than the angle of repose of the powder (FIG. 4).

In the tilted position (dotted lined) of the powder harp (FIG. 4), the connecting pipe 26, terminating in the frontal side of chamber 22, is now provided above the connecting pipe 28, terminating in about the center in chamber 22. The powder now flowing from the bottom" connecting pipe 28 fills the bottom left half of the chamber in FIG. 2, while the upper" connecting pipe 26 supplies the upper right half of the chamber with powder. In this manner, it is made certain that the entire chamber is sufficiently supplied with powder from the storage container, so that powder flows into the outlet channels 44 from all connecting conduits 42 and is conveyed onto the work piece from the entire outlet slot 48 (or' bores) extending over the breadth of the powder harp.

The novel powder harp is thus usable both for top surface as well as side surface flame scarfing and particularly also for selective flame scarflng, wherein it is necessary to carry out numerous flame-scarfing processes often in quick succession in order to eliminate individual faults on the work piece surfaces. Here it is particularly important that after the turning off of the conveying medium (channels 44) and of the supplemental conveying medium (conduit 34) no powder reach into the outer channels, something which is prevented in an advantageous manner by the presence of the connecting conduits 42 (safety zone S). Even with a tilting of the powder harp, this is afforded, since the connecting channels 42 with their longitudinal axis move in a circular path about the swivel point of the flame-scarfing torch or about point of rotation M.

In accordance with the exemplary embodiment of FIG. 2 it is only possible to supply with powder aside from the top surface, only the left side surface of the work piece, seen in the direction of flame scarfing. In order to be able to process the right side surface of the work piece also, it is feasible to undertake the arrangement of the two connecting

pipes

26, 28 in FIG. 2 in a mirror-like manner, i.e. the connecting pipe 26 is now provided on the left, in FIG. 2, frontal side of chamber 22.

It is also preferably possible, as indicated in FIG. 2 by dotted lines, to arrange a third connecting pipe 26 a at the other frontal side and in particular more suitably in a mirror-like manner to connecting pipe 26. In this way it is afforded that with the aid of such a powder harp, both side surfaces of the work piece facing each other may be supplied with powder by a single powder harp. In this instance, it is suitable to provide the middle connecting pipe 28 vertically, i.e. its longitudinal axis 40 and the longitudinal axis 24 of chamber 22 intersect at an angle of 90. Since, preferably on the basis of the selective use of the powder harp at both side surfaces, only the upper connecting

pipe

26 or 26a supplies powder to the chamber and in this case the lower" connecting

pipe

26 a or 26 may be closed off, it is furthermore within the scope of the invention to mount the middle connecting pipe 28 jointedly in the main block 16 in order to parallel align it in a given case with the outer connecting

pipe

26 or 26 a, whichacts precisely as the powder supply.

What is claimed -is:

1. In a device for applying flame-scarfing powder to the surfaces of work pieces to be flame-scarfed with a conduit for supplying the powder from a storage container into a chamber in the device and with an outlet conduit connected with the chamber through which the powder may be supplied with the aid of a conveying medium to the work piece surface, the improvement being said powder supply conduit having at least two branches, one of said branches terminating in about the center of said chamber, the other of said branches being connected to the frontal side of said chamber, said outlet conduit being in the form of a plurality of side by side outlet channels, and each of said channels communicating with said chamber.

2. In the device of claim 1 wherein each of said conduit branches terminates in a rigid pipe rigidly connected with said chamber.

3. In the device of claim 2 wherein said connecting pipes are parallel to each other.

4. In the device of claim 3 wherein said chamber has a longitudinal axis, and said connecting pipes are disposed at an angle of between about 30 and with respect to said longitudinal axis.

5. The device of 'claim 4 wherein the angle of said connecting pipes is about 60.

6. in the device of claim 3 wherein said powder supply conduit includes means for conveying a supplemental medium for transporting the powder.

7. In the device of claim 1 wherein said powder supply conduit includes means for conveying a supplemental medium for transporting the powder.

8. In the device of claim 4, in combination therewith, a flame-scarfing torch, said device beingmounted on said 'flame-scarfing torch, said flame-spraying torch being rotatable about an axis directed in the flamespraying direction for flame-s'carfing the top and side surfaces of the work piece, a storage container for the powder, said mounting means connecting said powder supply conduit for communication between said storage container and said device to provide a constant powder flow regardless of the tilt position of the flamescarfing torch. I I

9. In the device of claim 8 wherein said supply conduit includes a further branch connected to the side of said chamber remote from other of said branches and disposed as a mirror image thereof.

11. In the device of claim 8 wherein each of saidbranches includes a flexible hose connected to its rigid pipe to permit said device to be moved to different positions.

Claims

4. In the device of claim 3 wherein said chamber has a longitudinal axis, and said connecting pipes are disposed at an angle of between about 30* and 75* with respect to said longitudinal axis.

5. The device of claim 4 wherein the angle of said connecting pipes is about 60*.

8. In the device of claim 4, in combination therewith, a flame-scarfing torch, said device being mounted on said flame-scarfing torch, said flame-spraying torch being rotatable about an axis directed in the flame-spraying direction for flame-scarfing the top and side surfaces of the work piece, a storage container for the powder, said mounting means connecting said powder supply conduit for communication between said storage container and said device to provide a constant powder flow regardless of the tilt position of the flame-scarfing torch.

10. In the device of claim 8 including conveying medium means communicating with said device at the upstream end of said outlet channels, fluid means being disposed at the downstream end of said outlet to create underpressure therein, and said storage container containing said powder in the form of iron dust.

11. In the device of claim 8 wherein each of said branches includes a flexible hose connected to its rigid pipe to permit said device to be moved to different positions.