JP5523928B2 - Arc spraying equipment - Google Patents

Description

  The present invention relates to an arc spraying apparatus. More specifically, the nozzle internal shape of an atomizing (spraying) air nozzle is changed to a new shape, the supply state of jet air is changed, and the atomizing area is expanded. As a result, even if the arc spray amount (kg / hour) is increased, the arc spray metal droplets can be uniformly atomized at a low temperature to form a stable low temperature sprayed coating, and the working efficiency can be greatly improved. The present invention relates to an arc spraying apparatus.

  In general, there are five types of supply of atomizing jet air for arc spraying equipment: penetrating type, penetrating type combining outer envelope air, outer parcel type, outer parcel type combining auxiliary air, and parallel slitter type. There is a method.

  As shown in Patent Document 1, the first penetration type is directly applied from the rear of the arc region to the arc point to a metal droplet of a pair of metal spray materials obtained by melting the main jet air for atomizing with arc heat. By spraying, the metal droplets are reliably extruded and atomized, so that continuous spraying is possible.

The type in which the envelope air is combined with the second penetrating die performs atomizing by directly spraying the main jet air, which is jetted from the center rear of the arc region toward the arc region, onto the metal droplet, and Then, a cone-shaped air curtain is formed on the outside at a pressure of about 4 kgf / cm ² to spray the atomized metal droplets.

  As shown in Patent Document 2, the third outer envelope type is formed by ejecting main jet air in a conical shape from an annular nozzle, forming a jet curtain on the outside of the arc region, and using only a suction air flow generated by the main jet air. Spraying is possible by sending the droplets to the main jet air curtain and performing atomization.

  As shown in Patent Document 3, since the suction force is weak only with the main jet air curtain in the outer envelope mold, the mold that combines auxiliary air with the fourth outer envelope mold is provided with an auxiliary nozzle at the center rear of the arc region, By ejecting auxiliary air toward the center of the arc region, the metal droplets are surely pushed out to the main jet air, enabling continuous spraying.

  As shown in Patent Document 4, the fifth parallel slitter type forms a wedge type in which the main jet air curtain faces each other with respect to the thermal spray center axis, with the center lines of a pair of rectangular air nozzle openings in parallel. To do. Arc discharge of a pair of metal sprayed materials continuously at the position behind the central axis toward the converging air portion in the air chamber formed by the generating area of the suction force generated inside the main jet air and the sidestream of the weak wind Let Metal droplets of a metal spray material generated by arc discharge are fed into jet air together with suction force and air in the collateral sphere of weak wind to atomize the metal droplets.

  In recent years, in the world of painting, problems such as prohibition of lead coating, stricter regulations on organic solvents, and early deterioration of paint films and plating films have occurred due to acid rain and salt damage. As an alternative method, an inorganic material is used, and thermal spraying resistant to acid rain and salt damage has attracted attention. However, thermal spraying is higher in cost and lower in work efficiency than coating, and it is limited to rust prevention in limited places and other uses are limited to special applications such as overlaying and ceramics. No amount needed. In order for spraying to replace paint, it was necessary to reduce costs, improve work efficiency, and increase the amount of spraying.

In general, in an apparatus such as arc spraying or flame spraying (combustible gas spraying method), if the amount of spraying is increased, the metal melting temperature must be set extremely high and the melting energy needs to be set large, so that the spraying apparatus is large. A problem arises. As a result, the atomization efficiency of the metal droplets decreases, the sprayed coating becomes rough, and the coating performance deteriorates. Since the spray coating temperature also increases, the metal burns and changes color. Further, there are many problems such as generation of fume and dust, and the working environment becomes extremely poor.
From the above, the amount of spraying (kg / hour) for obtaining a coating state that can be used as a sprayed coating for arc spraying or flame spraying is limited, and there is a problem that the spraying amount cannot be easily increased.

In addition, in equipment such as arc spraying and flame spraying (combustible gas spraying method), when the sprayed coating temperature is high, the metal shrinkage due to cooling greatly acts after the sprayed coating is applied, and the contact surface with the base material to be sprayed A temperature shift occurs and causes peeling. Therefore, in order to lower the spray coating temperature by lowering it, it is necessary to lengthen the cooling time. Therefore, spraying is performed away from the base material to be sprayed, and the spray distance in that case is required to be 200 mm or more. Therefore, when spraying a sprayed base material such as uneven parts with large steps, edges, corners, complicated shapes, etc., it is possible to accurately maintain the distance to each target spray position. Since it is not possible to secure an appropriate amount of coating, an unnecessary sprayed coating may be deposited thickly, resulting in low-efficiency work with variations in film thickness. Peeling or the like due to the highness will occur. In order to solve these problems, it is necessary to secure a stable film thickness at a pinpoint with respect to the target spraying position. For this purpose, it is necessary to shorten the spraying distance and obtain a stable low-temperature sprayed coating even at a close distance. However, the conventional apparatus has a problem that the spraying distance cannot be shortened because it causes peeling.
Further, the coating efficiency of the sprayed coating is greatly influenced by the spraying distance, and the spraying distance is about 70% when the spraying distance is 50 mm to 200 mm, and about 50% or less when the spraying distance is 300 mm to 400 mm.
If the coating efficiency falls, the environment deteriorates because a lot of dust is generated. Moreover, since many spraying wires are needed, it leads to high cost.

JP 61-181560 A JP 61-167472 A Japanese Patent Publication No. 56-10103 Japanese Patent No. 2799718 Japanese Patent No. 2742536

  Regarding the above five methods, when the spraying amount is increased, a place where it is difficult to secure the conventional spraying distance, etc., and to secure a stable film thickness pinpoint to the target spraying position. In order to cope with this, there is the following problem when the spraying distance is shortened to try to spray at a close distance.

In the first through type, since the main jet air is directly blown onto the metal droplet melted by arc heat, the temperature of the metal droplet in the arc region is lowered. For this reason, in the penetration type, it is necessary to increase the melting voltage and perform arc discharge, and the loss of energy and the increase in the melting temperature are large compared to other types. In order to lower the melting temperature, the main jet air pressure must be set as low as about 4 kgf / cm ² , resulting in insufficient atomization and coarse coating particles. For this reason, in a penetration type, it must inevitably be high-temperature spraying. Further, since the main jet air is blown directly from the back of the center of the arc region to the arc point, there is a drawback that metal droplets are scattered over a wide range outside the target.

Furthermore, if the amount of spraying (kg / hour) is to be increased, more energy is required to melt the metal spray material, and the melting voltage must be increased. As a result, the temperature of the metal droplets increases and a lot of fumes are generated. In the penetrating type in which the main jet air pressure directly sprayed on the metal droplets cannot be increased to about 4 kgf / cm ² or more, the metal droplets cannot be completely atomized and the tendency to become a high-temperature rough coating becomes remarkable. .
Moreover, since atomization is insufficient and stable metal droplets cannot be obtained, it is difficult to perform spraying by reducing the conventional spraying distance.

In addition, the die that combines the second penetrating die with the outer air is used to wrap the arc region with a cone-shaped or cylindrical air curtain and to spray the main jet air directly from the rear center of the arc region to the arc point. Although the defect that metal droplets scatter in a wide range outside the range can be eliminated, the penetration type defect that the energy loss and the rise in melting temperature are larger than other types remains. Further, if the spraying amount (kg / hour) is increased, the same problem as the penetration type occurs.
This type concentrates jet air at the tip of the cone to induce metal droplets, and directs metal droplets to be scattered over a wide area to the base material so that they do not spread further with cylindrical jet air. However, if the spraying distance is reduced as in the case of the penetration type, the coating must be formed at a high temperature of the sprayed coating, which causes peeling.

In the third envelope type, the metal droplets are concentrated at one point on the top of the cone, so the density of the fine metal droplets is high and non-uniform, and the temperature of the spray coating does not decrease. Therefore, the difference between the melting temperature due to arc discharge and the spray coating temperature is very small. In addition, since the suction force is weak just by reducing the pressure in the main jet air curtain, spraying is possible for a short time, but there is a problem that metal spray adheres to the vicinity of the air nozzle when continuous spraying is performed. It is impossible to increase. Moreover, in the said patent document 2, the meaning of "low temperature spraying" means that the melting temperature by arc discharge is low, and does not mean that the thermal spray coating temperature becomes low.
Moreover, since the density of fine metal droplets is high and non-uniform, the adhesion strength of the coating is weak. Furthermore, since the temperature of the coating does not drop to a low temperature and causes peeling, the conventional spraying distance must be ensured. Thereby, it is difficult to shorten the spraying distance.

  In the type in which auxiliary air is combined with the fourth outer envelope type, when the spraying amount is increased, a metal droplet melted by arc heat is applied to a jet air curtain in which the main jet air is converged to one point of the apex of the conical shape. In the enveloping-type method of atomizing, the increased amount of metal droplets converges to one point, and when the density of fine metal droplets increases, the cooling efficiency decreases, the metal droplet temperature does not decrease, and the atomization efficiency decreases. The coating becomes rough and a uniform and fine spray coating cannot be obtained. Further, if the metal droplet temperature does not decrease, the sprayed coating temperature increases, and the metal shrinkage due to subsequent cooling increases, which causes peeling. Further, if a uniform fine metal droplet is not obtained, the sprayed coating is uneven.

Furthermore, if the atomized metal droplets overlap and form a small circular spray pattern without lowering the temperature, a high-temperature film in which the metal droplets are concentrated is formed, resulting in poor work efficiency.
As described above, a similar state occurs even when the spraying distance is shortened without increasing the amount, and therefore, it is impossible to perform spraying at a close distance by shortening the conventional spraying distance.

Further, in addition to the main energy for melting the metal spray material with arc heat, in order to spray about 1 kgf / cm ² of auxiliary air pressure to the arc region, extra melting energy for preventing cooling by the auxiliary air is required. In addition, the amount of energy lost to add metal droplets to the main jet air curtain is surely added, and arc discharge inevitably requires high voltage and high energy, reducing power consumption. There was a drawback that could not be done.

  In the fifth parallel slitter type, a uniform and high-pressure powerful jet air curtain cannot be obtained in the entire longitudinal width of the longer air nozzle port, and the suction force generated inside the main jet air is weak. In addition, the air distribution was non-uniform in the place where the main jet air ejected with the width of the rectangular air nozzle opening collided, and the sprayed pattern had only a small elliptical shape because the crossed air did not spread greatly up and down.

Therefore, even if the spraying amount (kg / hour) is increased as it is, it is a low-pressure main jet air curtain with non-uniform air distribution, so that the increased amount of metal droplets cannot be uniformly atomized. In addition, in the case of a small elliptical spray pattern, the temperature of the sprayed coating is increased, resulting in a problem that a non-uniform rough coating is formed.
As described above, the same state occurs even when the spraying distance is shortened without increasing the amount, so that there is a problem that the conventional spraying distance cannot be shortened to perform spraying at a close distance.

Further, the fifth parallel slitter type is deformed, and the center line in the width direction of the pair of jet airs inclines opposite to each other with respect to the spray spray center axis, and the pair of jet airs converge while partially converging. The parallel slitter type described in Patent Document 5 in which the parallel nozzle ports are oriented is intended to enlarge the spray coating pattern, but the jet direction of the pair of jet airs is not parallel to the wedge type. Therefore, the left and right sides of the arc chamber in the jet air curtain are not uniformly covered by the jet air curtain.
As a result, there is a problem in that the metal droplets leak sideways from a place not covered with the air curtain.

In addition, since the intersecting portion of jet air is smaller than the normal parallel slitter type and the atomizing area is narrow, when the spraying amount is increased, the increased metal droplets cannot be uniformly atomized, and the uneven rough coating There was a problem.
In order to solve this, it is necessary to set the vertical crossing angle of a pair of air curtains so that they intersect as close as possible in parallel, but there is a problem that the sprayed coating pattern will not change if it is close to parallel. there were.

  The present invention takes such a conventional technique into consideration, and it is difficult to work at a short distance in a place where a small amount of spraying, which is a drawback of the conventional spraying apparatus, cannot ensure the conventional spraying distance. In order to overcome all of the performance, low work efficiency, and high cost, the supply of main jet air is changed to a new shape for the air nozzle of the atomizing air nozzle and the inside of the air nozzle for the conventional parallel slitter type , Thereby spreading more uniformly atomized metal droplets, lowering the metal droplet temperature and spray coating temperature during atomization, and increasing the spray pattern to increase the spray amount. However, it is possible to form a stable low-temperature sprayed coating, and to provide a thermal spraying device that can significantly improve the work efficiency, and at a place where it is difficult to secure the conventional spraying distance. Also it is possible to enable high working efficiency and is intended to provide a spray apparatus capable of ensuring a stable film thickness pinpoint the target spraying position of.

  According to the first aspect of the present invention, a pair of melt nozzles for feeding and guiding the melt toward the arc intersection on the front surface of the thermal sprayer main body and a pair for supplying and guiding compressed air for atomizing to both sides of the pair of melt nozzles. A pair of planar jet air is ejected from the nozzle ports of the pair of nozzle units toward the spray center axis interposed between the nozzle ports of the pair of nozzle units. A jet air curtain is formed. On the other hand, an arc current is passed through the molten material to generate an arc discharge at the ends of a pair of molten materials in the jet air curtain to melt the molten material, and the molten droplets are sucked into the jet air. In the thermal spraying apparatus that is atomized, a cylindrical air tank that communicates with the nozzle opening of each nozzle unit is provided. Compressed air is sent from one end in the longitudinal direction of the tank, and the air is ejected from the nozzle opening at the tip of the air outlet passage provided on the side surface. The cross section of the air outlet passage on the side surface of the air tank is a corner portion. The angle formed by the two jet air heading toward the central axis of spraying by narrowing the width of the nozzle opening of the pair of nozzle units so that the arc intersection does not touch the jet air curtain so as not to form. A thermal spraying device with an acute angle was used.

  In the invention of claim 2, the nozzle unit is a slitter nozzle port. The width of each slitter nozzle port is 0.5 mm to 1.2 mm, the vertical width is 13 mm to 26 mm, and the width of the pair of slitter nozzle ports. The thermal spraying apparatus according to claim 1, wherein is 8 mm.

  According to a third aspect of the present invention, the nozzle unit is composed of a large number of small hole nozzle ports, the horizontal width of each small hole nozzle port is 0.5 mm to 1.2 mm, and the vertical width of the entire large number of small hole nozzle ports is The thermal spraying device according to claim 1, wherein the horizontal width of the nozzle unit is 13 mm to 26 mm and the pair of nozzle units is 8 mm.

  According to invention of Claims 1-3, the corner | angular part of the air exit channel | path of the side surface of the cylindrical air tank which leads to the nozzle opening of each nozzle unit is cut off, a cross section is made into a taper shape, and an arc intersection is a jet air curtain. The pressure of the compressed air sent into the air tank is reduced by narrowing the width of the nozzle openings of the pair of nozzle units and making the angle formed by the two jet airs toward the spray center axis to be acute. Since air can be uniformly ejected to the outside without dropping, the vertical width of the air curtain can be increased, the suction force in the arc chamber can be increased, and the atomizing region can be expanded.

  In addition, by this, if the spraying amount (kg / hour) is the same as the conventional one, the density of the metal droplets is lowered, so that the spraying amount can be increased. Moreover, since the loss of the air pressure of jet air is minimized and the pair of upper and lower parts which are jetted and widened in parallel are opened, the powerful air curtain expands in a fan shape up and down. And since the width of the intersecting air pattern has been expanded to more than twice the conventional size, a stable atomizing region can be expanded.

Therefore, by extending the arc chamber with a pair of parallel large air curtains, the problem that metal droplets leak sideways from the part not covered by the deformed parallel slitter type air curtain described in Patent Document 5 is solved. can do.
From the above, even if the spraying amount (kg / hour) is increased, uniformly atomized metal droplets can be diffused more, so compared to conventional spraying equipment, metal droplet temperature and spray coating temperature during atomization Can be lowered. Furthermore, even if the spraying amount (kg / hour) is increased, a uniform and stable sprayed coating pattern having a large elliptical shape can be formed, the spraying area per unit time can be expanded, and the working efficiency can be remarkably improved.

  Further, since the air suction rate in the arc chamber that has become stronger is higher than in the prior art, the state of low melting temperature can be maintained even if the amount of spraying is increased, and continuous spraying can be performed stably. In addition, since the metal droplets from the arc discharge are not exposed to the jet air curtain at the arc point, the low melting temperature can be maintained by the low temperature arc discharge, so the characteristics of the metal sprayed material can be improved even if the spraying amount is increased. Fume, scorching, dust, etc. can be suppressed without collapsing. In addition, even if the spraying amount is increased, the density of metal droplets is reduced compared to the conventional amount by expanding the stable atomizing region, and the metal droplet temperature and spray coating temperature during atomization are reduced. Therefore, the metal droplets can be prevented from being oxidized and the adhesion of the sprayed coating can be strengthened.

  In addition, since the stable atomizing area is expanded and the air pressure of the jet air is minimized, the suction force generated inside the jet air curtain is increased, and the molten metal droplets are easily expanded greatly. In addition, since the metal spray material is uniformly melted into fine metal droplets and sprayed onto the base material to be sprayed, unevenness of the formed coating can be suppressed even if the spraying amount (kg / hour) is increased. .

  Further, as described above, the thermal spray coating close to room temperature has little metal shrinkage due to cooling, and strong adhesion can be obtained even if the roughening rate of the base material to be sprayed is low. Accordingly, thermal spraying can be performed on a base material to be sprayed, such as paper, board, concrete, and the like, and the amount of spraying (kg / hour) can be increased.

  Further, aluminum and copper, which are metal spray materials that could not be easily sprayed by a conventional arc spraying device because of low resistance, the stable atomizing region is expanded in the spraying device of the present invention, and By minimizing the loss of air pressure of jet air, the suction force generated inside the jet air curtain increases, and the molten metal droplets spread easily and greatly, so that the melting efficiency can be significantly increased, Low temperature coating and fine coating spraying became possible. Moreover, even if the spraying amount was increased, the sprayed coating of aluminum or copper, which had been apt to become unstable, became uniform and stabilized by expanding the spraying pattern.

  Moreover, since the metal droplet temperature and the spray coating temperature during atomization are lowered by lowering the density of the metal droplets, the distance between the spraying device and the base material to be sprayed is, for example, 50 to 100 mm in the conventional spraying amount. Even when the film is shrunk, the contraction of the metal droplets due to cooling does not occur during the formation of the film, and the adhesion of the sprayed film can be strengthened. Moreover, since the thermal spray pattern is expanded, even if the distance between the thermal spraying device and the base material to be sprayed is reduced to 50 to 100 mm, a thermal spray area comparable to that in the case of the conventional thermal spray distance (200 to 300 mm) can be secured. Therefore, since it is possible to perform highly efficient work even in a place where it is difficult to secure the conventional spraying distance, the workability of spraying has been greatly improved. In addition, since the film thickness can be pinpointed and stabilized with respect to the target spraying position, the quality has improved dramatically.

  In the arc spraying apparatus, two jets heading toward the central axis of spraying are made such that the arc intersection does not touch the jet air curtain, and the pair of nozzle units is narrowed so that the molten droplet is pulled by the jet air curtain. The angle formed by the air was set to an acute angle, and the corner of the air outlet passage on the side surface of the cylindrical air tank leading to the nozzle port of each nozzle unit was cut off to make the cross section tapered.

A first embodiment of the arc spraying apparatus of the present invention will be described with reference to FIGS.
In FIG. 3, the arc spraying apparatus performs arc spraying using a linear metal spraying material W, and the metal spraying material W passes through the box-type spraying machine main body 1 in a vertically parallel posture. A thermal spray material path is set, a thermal spray material feed mechanism 2 is provided in the center of the thermal sprayer main body 1, and a nozzle 3 that ejects compressed air for atomizing is disposed on the front surface of the thermal sprayer main body 1.

  Insulating blocks 4 and 5 are fixed to the front and rear of the thermal sprayer main body 1 with a space therebetween, and the upper and lower sides defining the passage route of the metal thermal spray material W in a state of passing through the insulating blocks 4 and 5 forward and backward. A pair of guide tubes 6 and 7 are arranged in parallel. The rear guide tube 7 is directly fixed to the insulating block 5. The front guide tube 6 is fixed by being screwed into a pair of upper and lower electrode rods 8 mounted on the insulating block 4.

  As shown in FIG. 4, one end of each electrode rod 8 protrudes from the outer surface of the thermal sprayer main body 1, and a feeding line 9 is connected to the protruding end so that a positive current flows through one electrode rod 8. A negative current is applied to the other electrode rod 8, and an arc current is applied to the metal spray material W through the pair of guide tubes 6 and an arc guide tube 10 described later. In FIG. 4, one electrode bar 8 and the power supply line 9 are shown, and the other electrode bar 8 and the power supply line 9 are not shown.

  Further, as shown in FIG. 2, in order to move the metal spray material W toward the arc intersection point O on the front outer surface of the nozzle 3, each tip of the front guide tube 6 is curved in a “character shape”. The arc guide tubes 10 are connected and fixed, and each arc guide tube 10 projects forward from the front surface of the thermal sprayer main body 1. The arc guide tube 10 guides the upper and lower metal thermal spray materials W so as to converge toward the thermal spray center axis P, and is in close contact with the inner wall of the arc guide tube 10 at the time of the change to ensure the application of the arc current. It ’s a good thing.

  Further, as shown in FIG. 3, the thermal spray material feeding mechanism 2 is configured to feed the upper and lower metal thermal spray materials W simultaneously toward the front of the thermal sprayer main body 1. From a pair of upper and lower pressing rollers 13 (see FIG. 4, where only one pressing roller 13 is shown, the other not shown) that presses the thermal spray material W against the driving roller 12, and a motor 14 that rotationally drives the driving roller 12. Become. The drive roller 12 is made of an insulator, and a metal ring 12a having a substantially V-shaped cross section is crowned only at a portion circumscribing the metal spray material W. Further, a knurling for increasing friction is provided on the peripheral surface of the ring 12a.

  As shown in FIG. 4, the pressing roller 13 is rotatably supported by a pair of upper and lower swing arms 15 made of an insulator, and each swing arm 15 is supported by each leaf spring 16. It is urged to press against the drive roller 12. Thereby, each pressing roller 13 presses the metal spray material W against the peripheral surface of the ring 12a. As shown in FIG. 3, the motor 14 is housed in a grip 17 provided at the lower portion of the thermal sprayer main body 1 and can be activated by operating a switch 25 provided on the rear surface of the grip 17.

  1 and 2, the nozzle 3 is formed in a box shape, and a concave portion 18 that avoids the arc guide tube 10 is provided in the left and right center of the upper half. As shown in FIG. 5, a pair of rectangular slitter nozzle openings 19 are formed so as to be symmetrical with the thermal spray center axis P (see FIG. 1) interposed between the front surfaces on both sides of the nozzle 3 with the recess 18 interposed therebetween. Is open. Further, a joint 20 for connecting an air hose protrudes from the lower end of the nozzle 3 and is divided into two forks from the joint 20 to send compressed air to the left and right cylindrical air tanks 3a (see FIG. 3 and FIG. 3). (See FIG. 5). Each side of each air tank 3a has an air outlet passage 3b (see FIGS. 1 and 7) communicating with the slitter nozzle port 19. In addition, as shown in FIG. 6, the said recessed part 18 is provided in the right-and-left center of a lower half part, the coupling 20 is arrange | positioned at the upper end of the nozzle 3, and the structure which sends compressed air from the upper part to the left and right cylindrical air tank 3a ( An upside-down state in FIG.

  The rectangular slitter nozzle ports 19 are formed so as to be arranged in parallel in the vertical direction, as shown in FIG. 1, FIG. 5, or FIG. 6 and FIG. Each slitter nozzle port 19 is inclined so that its ejection center line Q converges toward the thermal spray center axis P. Further, in each of the air tanks 3a, as shown in FIG. 7, the corner of the air outlet passage 3b facing the slitter nozzle port 19 is cut off (the portion where the broken line portion is cut off), and the cross section is tapered. is there. Thereby, the compressed air sent from one end in the longitudinal direction of the cylindrical air tank 3a hits the other end of the air tank 3a, bends vertically, passes through the air outlet passage 3b, and is ejected from the slitter nozzle port 19. While maintaining the initial pressure over the entire width of the nozzle port 19, it can be ejected uniformly to the outside. In this regard, in the conventional structure in which the cross section of the air outlet passage 3b of the air tank 3a has a corner portion shown by a dotted line in FIG. 7, the compressed air hits the corner portion and the pressure is weakened.

  Further, when the horizontal width L of the pair of left and right slitter nozzle ports 19 shown in FIG. 5 is narrowed from the conventional one and a compressed air stream is ejected from the slitter nozzle ports 19, as shown in FIG. The jet air curtain 21 can be formed with an acute angle of the character shape, and the wedge-shaped arc chamber 22 formed in the inner region also has an acute angle. Further, as shown in FIG. 5, the width T of each slitter nozzle port 19 is narrowed from the conventional one and the vertical width H is increased, so that the air current blown out from the rectangular slitter nozzle port 19 extending in the vertical direction is used. The generated jet air curtain 21 is wider and exhibits stronger directivity as shown in FIG.

  For this reason, in FIG. 2, the upper and lower cross-sectional widths of the jet air curtain 21 outside the arc chamber are greatly expanded as compared with the prior art, and the arc chamber acts so as to cover the upper and lower portions of the arc point widely. Therefore, a stronger air flow wall having a sharp wedge shape is formed at both ends of each jet air curtain 21 by the air flow from the pair of slitter nozzle ports 19, and a stronger suction force is generated in the arc chamber.

  Next, the positional relationship between the nozzle 3 and the arc intersection point O of the metal thermal spray material W is determined so that arc discharge is performed in the jet air curtain 21.

  Specifically, as shown in FIGS. 1 and 2, the arc intersection point O is set on the thermal spray center axis P between the jet air curtain 21 and the front end of the nozzle 3. That is, the arc intersection point O is set at a position where the arc region of the metal spray material W does not directly touch the jet air curtain 21.

  When arc spraying is performed by the above air supply mode, the arc portion of the metal spray material W is not directly exposed to the air of the jet air curtain 21, and the arc chamber 22 is covered with the jet air curtain 21 widely. Arc discharge is possible. At this time, the arc chamber 22 created by the pair of jet air curtains 21 forms a very acute area, but a pinch phenomenon that occurs when the jet air curtain 21 is touched during arc discharge does not occur. Moreover, the metal droplet generated by the arc discharge is sent to the airflow zone of the jet air curtain 21 mainly by suction and atomized.

  The horizontal width L of the pair of slitter nozzle ports 19 and the horizontal width T and vertical width H of each slitter nozzle port 19 were determined based on the following experiment.

  First, in a conventional parallel slitter type thermal spraying apparatus, jet air is ejected from a pair of slitter nozzle ports arranged symmetrically with respect to the thermal spray central axis P toward the thermal spray central axis P, and the thermal spray causes the thermal spray central axis to flow. A jet air curtain for atomizing that converges at the tip of P is formed, and in the arc chamber in the jet air curtain, a pair of metal thermal spray materials W in a side sphere composed of weak wind derived from the jet air curtain In this case, arc discharge is continuously performed, and metal droplets generated thereby are sent into the jet air curtain by the weak wind in the troposphere to perform atomization. The width L of the pair of slitter nozzle ports is 16 mm, the width T of each slitter nozzle port is 1.5 mm, and the vertical width H is 10 mm.

  Therefore, in the present invention, by increasing the vertical width H10 mm of each slitter nozzle port 19 to 13 mm to 26 mm, the portion where the main jet air intersects becomes larger, and the refined metal droplets spread uniformly over the air width. The spray coating pattern is enlarged and a low temperature spray coating can be obtained. However, by increasing the vertical width H10 mm to 13 mm to 26 mm, the portion where the main jet air intersects increases, but each slitter nozzle 19 It was found that the jet air pressure was not uniform when the horizontal width of the nozzle was 1.5 mm. This could be demonstrated by the following experiment.

  Several types of slitter nozzle ports 19 having different widths T and H were prepared, and experiments were performed to obtain the characteristics of the air currents ejected from the slitter nozzle ports 19 and the generated jet air curtain 21. However, since observation with air cannot be performed visually, it was decided to visually check the state of water flow by flowing water through the air nozzle port.

  The structure of the sprayed air nozzle 3 is that jet air enters the left and right cylindrical air tanks 3a from the joint 20 at the lower part, hits the upper wall in the air tank 3a, bends vertically, and passes through the air outlet passage 3b on the side. Air is ejected from the slitter nozzle port 19 through the air.

  In the slitter nozzle port 19 having a conventional horizontal width T of 1.5 mm and a vertical width H of 10 mm, water concentrates and discharges strongly at the top of the vertical width H of 10 mm, and only a small amount of water is ejected from the lower part. From 19, water was not ejected uniformly. The results obtained in this water nozzle water flow test were reproduced in the same way with thermal spraying. When thermal spraying was performed with the slitter nozzle port 19, the sprayed coating pattern had an elliptical shape close to a circle and the upper part was atomized, but the lower part was weakly atomized and rough.

  When the slitter nozzle port 19 has a horizontal width T of 1.5 mm and a vertical width H of 18 mm, water concentrates and discharges strongly on the top of the vertical width H18 mm, and only a small amount of water is ejected from the bottom. The tendency that water did not spout uniformly from the mouth 19 became stronger. The results obtained in this water nozzle water flow test were reproduced in the same way with thermal spraying. When spraying was performed with the slitter nozzle port 19, the sprayed coating pattern became elliptical, and the atomization of the upper part was slightly weak and the atomization of the lower part was very weak and rough.

  Therefore, although the width T of each pair of slitter nozzle ports 19 is narrowed, the air flow becomes worse and the air pressure decreases. This could be demonstrated by the following experiment.

  A slitter nozzle port 19 having a horizontal width T narrowed to 1.0 mm and a vertical width H of 10 mm was prepared. In the water flow test at the slitter nozzle port 19, water was uniformly discharged with a width of 10 mm. However, although water was uniformly discharged with a width of 10 mm, the water pressure was weaker than that of the slitter nozzle port 19 having a width T of 1.5 mm. The results obtained in this water nozzle water flow test were reproduced in the same way with thermal spraying. When the slitter nozzle opening thermal spray test was performed, the thermal spray coating had an elliptical pattern close to a circle, and a thermal spray coating uniformly atomized on both the upper and lower portions was formed. However, in the place where the main jet air ejected with the width of the rectangular air nozzle mouth collides, the vertical width H of the air is 10 mm, and the cross air width is not large, so the spray pattern only has a small elliptical shape. .

  Therefore, a slitter nozzle port 19 having a horizontal width T of 0.8 mm and a vertical width H of 18 mm was prepared. In the water flow test at the slitter nozzle port 19, water was uniformly discharged with a width of 18 mm. However, water was uniformly discharged with a width of 18 mm, but the water pressure was weaker than that of the slitter nozzle port 19 with a vertical width of 10 mm. The results obtained in this water nozzle water flow test were reproduced in the same way with thermal spraying. When the thermal spraying test was performed with the slitter nozzle port 19, the metal droplets were uniformly atomized and the thermal spray coating became an elliptical pattern. However, since the air pressure is weak at the place where the main jet air ejected with the width of the rectangular air nozzle opening collides, the atomization of the metal droplets is poor and the spray coating temperature does not drop. Based on this result, the following changes were made.

  In the cylindrical air tank 3a of the slitter nozzle port 19 having a horizontal width T of 0.8 mm and a vertical width H of 18 mm, a corner portion of the air outlet passage 3b that communicates with the slitter nozzle port 19 provided on the side surface of the air tank 3a. A nozzle was prepared by cutting the cross section into a tapered shape. In the water flow test of the slitter nozzle port 19, the pressure of the water ejected from the slitter nozzle port 19 is stronger than the slitter nozzle port 19 in which the horizontal width T is 0.8 mm and the vertical width H is 18 mm. The nozzle port 19 was uniformly discharged with a vertical width of 18 mm.

  When a thermal spray test is performed at the slitter nozzle port 19, the metal pressure is reduced when the air intersects as shown in FIG. 2 because the air pressure is increased at the point where the main jet air intersects. Compared with the conventional type, the air jet spreads uniformly over the entire range of the air, and the main jet air spreads in a fan shape in the vertical direction. An elliptical thermal spray coating was formed. The results obtained in this water nozzle water flow test were reproduced in the same way with thermal spraying. As a result, it has been found that the air flow is improved, the problem of lowering the air pressure can be solved, and the air pressure can be increased more than the conventional type.

  Further, an air nozzle was prepared in which the pair of lateral widths L of the slitter nozzle port 19 was reduced from 16 mm to 8 mm, and the air crossing angle was made sharper than the conventional type by taking the air crossing point at the conventional position. In the water flow test at the slitter nozzle port 19, the water pressure of the water flow curtain is not lost at the point where the curtains of the water flow ejected from the slitter nozzle port 19 intersect, and the water flow is strongly forward compared to the conventional slitter nozzle port 19. Water erupted.

  When the spraying test was performed with the slitter nozzle port 19, atomization of the metal droplets was further improved, both the spraying energy consumption and the spraying voltage could be lowered, and the spray coating temperature also decreased. In addition, a large elliptical thermal spray coating could be formed in the thermal spray pattern. Therefore, when the thermal spraying test was performed with the thermal spraying amount increased, a good thermal spray coating equal to or better than the thermal spraying with the conventional air nozzle could be formed.

  Based on the results of the above experiment, in the apparatus of the present invention, the horizontal width T of each of the pair of slitter nozzle ports 19 arranged symmetrically with respect to the thermal spray central axis P is narrowed to 0.5 mm to 1.2 mm, and the vertical width H Is expanded to 13 mm to 26 mm, the width L of the pair of slitter nozzle ports 19 is narrowed to 8 mm, and an air intersection is taken at the conventional position.

  With such a new shape, the cross-sectional width of the jet air curtain 21 of the arc chamber 22 greatly expands in the vertical direction as compared to the conventional case, and the arc chamber 22 acts to cover the vertical direction of the arc point widely, and It has been found that the atomizing region greatly expands because the intersecting jet air curtain tip 21a extends forward. Further, the airflow ejected from the pair of slitter nozzle ports 19 is stronger than that of the conventional type, and a sharp wedge-shaped stronger airflow wall is formed at both ends of each jet air curtain 21. Due to the air flow, a force that strongly attracts metal droplets is generated in the arc chamber.

As a result, metal droplets generated by arc discharge of the metal spray material W in the arc chamber 22 surrounded by the large jet air curtain 21 formed by the pair of slitter nozzle openings 19 are made to be larger than the conventional one in the arc chamber 22. It was confirmed that it could be reliably fed into the jet air curtain 21 with a strong suction force, and that stable atomization was performed.
Further, since the pair of air curtains form an acute angle, the loss of air pressure after crossing can be reduced as compared with the conventional case.

  Furthermore, the main jet air pressure is increased in order to expand the atomizing region and to easily diffuse the molten metal droplets easily.

Therefore, the test was conducted at main jet air pressures of 4, 5, 6, 8, 9, 10 kgf / cm ² .
(1) Thermal spraying of 4 kgf / cm ² is good, but the thermal spray coating particles are a little rough and the thermal spraying temperature is a little high. It was in the same state as the thermal spraying of air pressure 6 kgf / cm ^{2 to} 7 kgf / cm ² of the conventional thermal spraying air nozzle.
⁽²⁾ spraying 5kgf / cm ² ~6kgf / cm 2 is satisfactory, the spray coating particles finer, spray coating temperature is low.
⁽³⁾ spraying 7kgf / cm ² ~8kgf / cm 2 is very good, even if increasing the spraying amount was the same condition as in the above (2).
⁽⁴⁾ 9kgf / cm 2 sprayed coating is ultra atomized in spraying ~10kgf / cm ^2, the spray coating temperature is low, spraying the adhesion strength becomes higher. The pores of the sprayed coating were too small to measure.
In all cases described above, the thermal spray coating was good.

  In the second embodiment of the present invention, as shown in FIG. 8, instead of the pair of slitter nozzle ports 19 of the first embodiment, a plurality of small hole nozzle ports 19a and 19b are used. The diameter of the nozzle port 19 a is the same as the horizontal width of the slitter nozzle port 19, and the vertical width of all the small hole nozzle ports 19 a and 19 b is the same as the vertical width of the slitter nozzle port 19. Further, the lateral width of the pair of small hole nozzle ports 19 a and 19 b is the same as the width L of the pair of slitter nozzle ports 19. The small hole nozzle ports 19a are located above and below each of the left and right rows, and there are several small hole nozzle ports 19b between the upper and lower small hole nozzle ports 19a of each row. It is smaller than the diameter of the small hole nozzle port 19a. Other configurations are the same as those of the first embodiment.

  In the case of the second embodiment, the same operation as that of the first embodiment is performed. The nozzle unit of the present invention includes the slitter nozzle port of the first embodiment and the many small hole nozzle ports of the second embodiment.

It is a partial cross section top view of arc spraying in the arc spraying apparatus of Example 1 of this invention. It is a side view of the arc spraying in Example 1 arc spraying apparatus of this invention. It is a longitudinal cross-sectional side view of the arc spraying apparatus of Example 1 of this invention. It is a cross-sectional top view of the arc spraying apparatus of Example 1 of this invention. It is a front view of the nozzle part of the arc spraying apparatus of Example 1 of this invention. It is a front view of the other form of the nozzle part of the arc spraying apparatus of Example 1 of this invention. It is an expansion cross-sectional view of the nozzle part of the arc spraying apparatus of Example 1 of this invention. It is a front view of the nozzle part of the arc spraying apparatus of Example 2 of this invention.

DESCRIPTION OF SYMBOLS 1 Thermal spray body 2 Spray material feed mechanism 3 Nozzle 3a Air tank 3b Air outlet passage 4 Insulation block 5 Insulation block 6 Guide tube 7 Guide tube 8 Electrode rod 9 Feed line 10 Arc guide tube 12 Drive roller 12a Ring 13 Pressing roller 14 Motor DESCRIPTION OF SYMBOLS 15 Oscillating arm 16 Spring 17 Grip 18 Recess 19 Slitter nozzle port 19a Small hole nozzle port 19b Small hole nozzle port 20 Joint 21 Jet air curtain 21a Jet air curtain tip 22 Arc chamber
31a Enlarged spray pattern 31b Conventional spray pattern
O Arc intersection P Thermal spray center axis W Metal thermal spray material

Claims (3)

A pair of parallel nozzle units that feed and guide a pair of melt nozzles to the front of the thermal spraying machine body toward the arc intersection and supply compressed air for atomization to both sides of the pair of melt nozzles A pair of planar jet air is ejected from the pair of nozzle units toward the spraying central axis interposed between the pair of nozzle units, and a jet air curtain having a wedge-shaped cross section is formed by these jet air, In an arc spraying apparatus in which an arc current is passed through the molten material, an arc discharge is generated at the tip of a pair of molten materials in the jet air curtain to melt the molten material, and the molten droplets are sucked into the jet air and atomized.
A configuration in which a cylindrical air tank leading to the nozzle port of each nozzle unit is provided, compressed air is sent from one end in the longitudinal direction of the air tank, and air is ejected from the nozzle port at the tip of the air outlet passage provided on the side surface The nozzle ports of the pair of nozzle units are tapered so that the cross section of the air outlet passage on the side surface of the air tank does not form a corner, and the arc intersection does not touch the jet air curtain. An arc spraying apparatus characterized in that the angle between two jet airs toward the thermal spray center axis is made an acute angle by narrowing the width of the spray.   The nozzle unit is a slitter nozzle port, and the width of each slitter nozzle port is 0.5 mm to 1.2 mm, the vertical width is 13 mm to 26 mm, and the horizontal width of the pair of slitter nozzle ports is 8 mm. The arc spraying apparatus according to claim 1.   The nozzle unit is composed of a large number of small-hole nozzle ports, the horizontal width of each small-hole nozzle port is 0.5 mm to 1.2 mm, and the vertical width of the entire large number of small-hole nozzle ports is 13 mm to 26 mm. 2. The arc spraying device according to claim 1, wherein the lateral width is 8 mm.

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