JPH0375350A - Arc spraying device for remote thermal spraying - Google Patents

Abstract

PURPOSE:To miniaturize a nozzle unit for remote thermal spraying and to carry out thermal spraying on a narrow part, etc., by injecting a planar air jet from a couple of air nozzles, positioning the arc intersection in a cuneate air chamber partitioned by the air jet and carrying out arc spraying. CONSTITUTION:A couple of long-sized hot charge conduit 2 and air conduit 3 for supplying and guiding the hot charge W and atomizing compressed air is extended from the front of a thermal spraying machine main body 1, and the nozzle unit 4 for remote thermal spraying is provided at the tip of the conduits 2 and 3. The unit 4 has a couple of thermal spraying nozzles 16 connected to each hot charge conduit 2 and used for supplying and guiding the hot charge W to the arc intersection Q and a couple of air nozzles 26 arranged with both nozzles 16 is between. Each air nozzle 26 has a nozzle port 32 for injecting a planar air jet 31, the port 32 is directed so that a convergent air current 34 is formed toward a melting center axis P of the air jet 31, and the arc intersection Q is set in the air chamber 35 enclosed by the air jet 31.

Description

[Detailed Description of the Invention] (A) Industrial Application Field This invention is applicable to thermal spraying in small, hard-to-reach parts of existing structures such as bridges and steel towers, thermal spraying on the inner surface of long pipe materials, etc.
This article relates to thermal spraying equipment suitable for thermal spraying at remote locations, and particularly targets arc-spraying type thermal spraying equipment.

(Example) Conventional technology For example, when forming a thermal spray coating on a narrow part of an existing structure, a normal thermal spraying apparatus cannot be used.

This is because the flying distance of the metal droplets is only several tens of degrees, and furthermore, it is difficult to insert the thermal spraying device into the narrow part. In particular, conventional arc spraying equipment (for example, Japanese Patent Laid-Open No. 61-1674
In the case of Publication No. 72, it is necessary to surround the outer surface of the arc intersection with a cone-shaped jet air, so a large-diameter air nozzle is essential, and it is difficult to downsize the thermal spraying equipment, so it is applied to the special purpose mentioned above. It was difficult to do so.

For these reasons, when performing remote thermal spraying on narrow areas, etc., it is recommended to use the gas thermal spray method, which allows for easy miniaturization of the thermal spray nozzle.
Device A was used exclusively (document unknown).

(c) Problems to be Solved by the Invention Gas spraying equipment has a high droplet temperature and cannot perform thermal spraying at low temperatures like arc spraying equipment.Therefore, combustible materials are removed from the area to be sprayed. This has the disadvantage that the preparation work for this requires time and effort.

In addition, because the powder-like continuous phase is ejected from a thermal spray nozzle and then melted with a gas flame for thermal spraying, the film forming efficiency is lower than that of arc thermal spray equipment, and the film forming process takes a long time. There was a disadvantage.

This invention has been proposed in view of the above, and has an object to miniaturize the nozzle unit for remote thermal spraying in an arc thermal spraying type thermal spraying apparatus with excellent film-forming efficiency, and to realize remote thermal spraying in narrow areas, etc. With the goal.

Another object of the present invention is to make the thermal spraying nozzle more compact while enlarging the thermal spraying pattern, thereby enabling the film forming operation to be performed efficiently in a short time.

(2) Means for Solving the Problems The arc spraying apparatus of the present invention has a
A long melt-sealing conduit 2.2 and an air conduit 3 for feeding and guiding the melt W and compressed air for atomizing are provided in a protruding manner, and a nozzle unit 4 for remote thermal spraying is installed at the tip of both conduits 2.3. provided and configured.

The nozzle unit 4 is arranged with a pair of welding material nozzles 16.16 that continuously feed and guide the welding material W toward the arc intersection point Q in the melt-sealing conduit 2.2, and both nozzles 16.16 sandwiched therebetween. It has a pair of air nozzles 26.26.

Further, the air nozzle 26.26 has a nozzle port 32 for ejecting planar jet air 31.
converges toward the central spraying axis P, and after converging, the convergent airflow 34
The jet direction of the nozzle opening 3.2 is oriented so as to form a jet. An air chamber 3 surrounded by jet air 31
It was decided that arc thermal spraying would be performed by positioning the arc intersection point Q within 5.

More preferably, the spraying direction of the nozzle opening 32 is set so that the jet air central axes R, R in the width direction of each jet air 31, 31 are inclined in opposite directions and intersect with each other, thereby enlarging the spray pattern.

(E) Function As mentioned above, in this invention, a pair of air nozzles 26.2
Planar jet air 31 is ejected from each of the holes 6 to atomize the droplets.

Therefore, the nozzle unit 4 for remote thermal spraying can be easily downsized compared to a conventional arc thermal spraying machine that atomizes droplets by ejecting cone-shaped jet air. The nozzle unit 4 can be inserted into the parts etc. without any trouble, and film formation can be performed reliably in every corner.

If the jet air 31.31 crosses the ejection center axes R, R in the width direction, the spray pattern S can be expanded in the direction of inclination of both jet air 31.31, so the nozzle unit 4 can be made smaller. Despite thermal spraying,
Film formation work can be performed efficiently.

(F) Embodiment FIGS. 1 to 9 show an embodiment in which the present invention is applied to an arc thermal spraying apparatus for existing structures such as bridges.

In FIG. 1, the arc thermal spraying apparatus includes a thermal spraying machine main body 1 which is operated by hand, a groove material conduit 2 and an air conduit 3 protruding from the front surface thereof, and a remote thermal spraying device provided at the tips of both conduits 2.3. It receives arc current and compressed air from a power unit (not shown),
The nozzle unit 4 is configured to spray the hot metal material W.

The thermal spraying machine main body 1 has a grip 6 on the bottom surface of a square box-shaped case 5.
is provided protrudingly to form an outer shell, inside which a pair of upper and lower heating materials W are placed.
A mechanism for feeding and driving the nozzle unit 4 toward the nozzle unit 4 is provided. This mechanism is composed of a pair of pulley-like upper and lower feed rollers 8 that are rotationally driven by a motor 7, a pressure roller 9 that presses and operates the hot material W against each feed roller 8, and the like. A pair of heating materials W introduced from the wall 5b side
are simultaneously fed and driven toward the front wall 5a. Both the front wall 5a and the rear wall 5b are made of an insulator. The hot material W is made of a round wire rod, and is fed out from a supply reel (not shown).

2 and 3, on the front surface of the case 5, a pair of upper and lower electrode rods 11 and 12, which are long in the left and right directions, and a joint block 13 for air supply, which is long in the vertical direction, are arranged in a non-contact manner. There is. Then, a groove material conduit 2 is attached to each electrode rod 11 and 12.
is fixed, and the air conduit 3 is fixed to the joint block 13. Both of these conduits 2.3 also serve as support arms for supporting the nozzle unit 4, and are both made of steel pipes. In addition, as shown in FIG. 1, the protruding ends of both conduits 2.3 are bent with a gentle bending radius so that the thermal spraying center axis P of the nozzle unit 4 is directed upward with respect to the protruding center axis of both conduits 2.3. It should be tilted. This inclination angle θ can be selected within the range of 0 to 90 degrees, and is set to 45 degrees in the illustrated example.

The groove material conduit 2.2 feeds and guides the hot material W, and also conducts the arc current applied to the electrode rod 11.12 to the nozzle unit 4 using its tube wall as a power supply path. Both conduits 2.
Each channel conduit 2.
An insulating tube 14 is placed on the outer surface of each of the two. Further, in order to facilitate the transfer of the hot material W within the conduit 2, a Teflon tube 15 is disposed inside the tube, and the hot material W is inserted into the inside of the Teflon tube 15.

The air conduit 3 is made of a steel pipe with a larger diameter than the groove material conduit 2, and feeds and guides compressed air supplied via the joint block 13 to the nozzle unit 4. The outer surface of this conduit 3 is also covered with an insulating tube 14 just in case.

In FIG. 4, the nozzle unit 4 includes both welding material conduits 2.
2, a pair of welding material nozzles 16.16 that feed and guide the hot material W toward the arc intersection point Q, and a pair of upper and lower nozzle holders 17.16 that connect each conduit 2 and each welding material nozzle 16.
17, a nozzle block 18 that blows out jet air for atomizing, the nozzle block 18 and the air conduit 3
It is composed of a joint fitting 19 for connecting the .

The nozzle holder 17 is made of a copper block with a convex cross-section, and as shown in FIGS. 6 and 7, a hot material passage 21 is formed in the center of the nozzle holder 17 and extends through the front and back.

The groove material conduit 2 is in communication with the rear part of the hot material passage 21.
is fixed to the nozzle holder 17.

Further, the melting material nozzle 16 is screwed and fixed in an inclined position to the nozzle holder 17 in a state where it communicates with the front part of the hot material passage 21. The transfer direction of the hot material W is changed by the welding material nozzle 16 , and at this time, it comes into strong contact with the inner surface of the hot material port 21 and receives arc current from the nozzle holder 17 .

As shown in FIGS. 4 and 7, the nozzle holder 17.
17 are four screws 22 with the nozzle block 18 in between.
are fastened together with. In order to insulate the upper and lower nozzle holders 17.17 in this fixed state, the joint surface between the nozzle holder 17 and the nozzle block 18, and the screw 22
An insulating plate 24 made of Bakelite is interposed on each of the fastening surfaces of the nut 23 and the nut 23. Further, an insulating tube 25 is fitted onto the outer surface of the shaft portion of the screw 22.

The nozzle block 18 includes a pair of left and right air nozzles 26.26 disposed with the sealing nozzle 16 in between, a base 27 sandwiched between the upper and lower nozzle holders 17, and a connection projecting from the rear surface of the base 27. The boss 28 is integrally formed, and the whole is formed in a single character shape when viewed from the side. As shown in FIG. 5, two air passages 29.29 are formed inside the nozzle block 18, corresponding to each air nozzle 26.26. These air passages 29,29 are connected to the air conduit 3 via fittings 19.

Nozzle ports 32 for ejecting planar jet air 31 are opened at the tip ends of the left and right air nozzles 26, 26, respectively. As shown in FIG. 8, the nozzle opening 32 is composed of a group of small holes 33 that form a straight line in the vertical direction, and as shown in FIGS.
Inject.

That is, the ejection direction of each nozzle port 32 is directed so that the jet air 31 converges toward the central axis P of thermal spraying and forms a convergent airflow 34 after convergence (FIG. 5).Furthermore, each jet air 31. The jetting directions of the left and right nozzle ports 32 are set so that the jetting central axes RSR in the width direction of [3] are tilted upside down and intersect with each other (Fig. 6). Air chamber 3 surrounded by
5, the above-mentioned arc intersection point Q is located.

When arc spraying is performed using the nozzle unit 4 configured as described above, even though atomizing is performed using only a pair of planar jet air 31, there is no pinch phenomenon or uneven spraying, and the condition is good. Thermal spraying can be performed. This makes it possible to miniaturize the nozzle unit 4 and perform remote thermal spraying on narrow parts of existing structures. In the illustrated example, the vertical and horizontal dimensions of the nozzle tip shown in FIG. 8 could be reduced to 30 m, respectively.

Further, the thermal spray pattern S obtained by the above-mentioned nozzle unit 4 has an oval or elliptical shape, as shown in FIG. 9, and the coating thickness on the thermal spray pattern surface can be made uniform. . If the jet air axes R in the width direction of both jet airs 31 are not tilted, a nearly circular thermal spray pattern as shown by the imaginary line will be obtained, but compared to this thermal spray pattern, the coating area of the thermal spray pattern S is is magnified 2.5 to 3 times.

As explained in FIG. 1, the thermal spraying central axis P of the nozzle unit 4 is inclined at 45 degrees with respect to the protruding central axes of the sealing conduit 2 and the air conduit 3. Therefore, by rotating the case 5 by hand around the protrusion central axis before spraying, the film can be easily formed all over the inner surface of the narrow part, and the above-mentioned spray pattern S can be formed. Combined with the magnification, thermal spraying work can be carried out efficiently.

Note that the protruding lengths of the melt-sealing conduit 2 and the air conduit 3 can be freely set in the range of several tens of cm to several urns as necessary;
If ease of use is the standard, 50cm to 150cm
ci position is preferred, and the illustrated example is approximately 100 cm.

(g) Another embodiment The above-mentioned arc thermal spraying apparatus can also be applied to the case of forming a thermal spray coating on the inner surface of a steel pipe, a PVC pipe, or the like. In this case, the target tube material is limited to a tube material cut into a length of 2 to 3 m or less, and the nozzle unit 4 is inserted alternately through each opening of the tube material to form a film. At this time, it is more efficient to perform film formation while rotating the tube material at a constant speed. Of course, 2
The film may be formed using a stand-up thermal spraying machine. When the diameter of the tube material is small, the inclination angle θ of the thermal spraying central axis P of the nozzle unit 4 is made small. In some cases, film formation may be performed with the inclination angle θ set to zero, with the entirety of the weld material conduit 2 and the air conduit 3 tilted with respect to the tube axis.

The melt conduit 2 and the air conduit 3 may each be formed of a flexible pipe such as a conduit pipe. In addition, when the weld material conduit 2 is formed of an insulating material, the conduit 2
Arc current may be supplied by placing a power supply cord along the arc.

The nozzle opening 32 does not need to be formed by a group of small holes, and may be formed as a slit-like groove.

The melting material W may be in the form of a belt.

(h) As described in detail, in this invention, a pair of air nozzles 26
．． A planar jet air 31 is ejected from each of the jet air 26, and the arc intersection point Q is located in a wedge-shaped air chamber 35 defined by the jet air 31 to perform arc spraying. Compared to a thermal spraying machine, the nozzle unit 4 for performing remote thermal spraying can be made smaller.

Thereby, the nozzle unit 4 can be inserted into the narrow part of the existing structure, the inner surface of the pipe material, etc. without any hindrance.
It has now become possible to reliably perform film formation on all narrow areas.

The jet air central axis R in the width direction of the pair of jet air 31.31
, R, both jet air 31.31
Since the spray pattern S can be enlarged in the direction of inclination, even though the nozzle unit 4 is downsized,
It is advantageous in that the film formation work can be carried out efficiently, and particularly when film formation is performed on an existing structure, the time and personnel required for the work can be reduced and the construction cost can be reduced.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, FIG. 1 is a side view of the arc thermal spraying apparatus, FIG. 2 is a view taken along the line ■-■ in FIG. 1, and FIG.
Figure 4 is a plan view of the nozzle unit; Figure 5 is a cross-sectional view taken along line v-v in Figure 4; Figure 6 is a cross-sectional view of the nozzle unit.
7 is a sectional view taken along the line ■-Vl in FIG. 4, FIG. 8 is a view taken along the ■ arrow in FIG. 4, and FIG. 9 is a pattern explanatory diagram showing the thermal spray pattern. . ...Jet air, 32...Nozzle opening, 34...Convergent airflow, 35...
・・・・・・Air chamber, W・・・・・・Welding material, P・・・・・・Thermal spraying center axis, Q・・・・・・・・・
・・・Arc intersection, R・・・・・・Ejection center axis.

Claims (2)

[Claims] (1) A long welding material conduit 2 that feeds and guides welding material W and compressed air for atomizing on the front of the thermal spraying machine main body 1;
2 and an air conduit 3 are provided in a protruding manner, and a nozzle unit 4 for remote thermal spraying is provided at the end of both conduits 2 and 3, and the nozzle unit 4 is provided with a nozzle unit 4 for remote thermal spraying.
, 2, a pair of welding material nozzles 16, 16 that continuously feed and guide the welding material W toward the arc intersection point Q, and both nozzles 1.
A pair of air nozzles 26 arranged with 6 and 16 in between.
, 26, each air nozzle 26, 26 has a planar jet air 31
The nozzle port 32 has a nozzle port 32 for ejecting a jet air, and the jet air 31 is oriented toward the central axis P of thermal spraying and forms a convergent airflow 34 after convergence. An arc thermal spraying apparatus for remote thermal spraying, wherein the arc intersection point Q is provided in an air chamber 35. (2) The remote thermal spraying device according to claim 1, wherein the jetting directions of the nozzle ports 32, 32 are set so that the jetting central axes R, R in the width direction of each jet air 31, 31 are inclined in opposite directions and intersect with each other. arc spraying equipment.