JP2017075353A - Spray coating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a spray coating device that suppresses the inside of a spray coating booth from reaching a high temperature even when the spray coating booth is compact.SOLUTION: A spray coating device 1 comprises a spray coating gun 10, a spray coating booth 40, a compressor 35, and a dust collecting machine 36. The spray coating gun 10 blows a spray coating flame 15 from a nozzle port 21 opposed to a work 50 to the work 50. The spray coating booth 40 is cylindrical and has the work 50 set inside, and the spray coating gun 10 is inserted. The flow velocity of a gas and the diameter of the spray coating booth 40 are so set that an air current flowing from an intake part 42 to an outlet part 43 in the spray coating booth 40 can pass through the spray coating flame 15. Consequently, the air current reaches even an exhaust side, and the heat quantity absorbed from the gas in the spray coating booth 40 and a wall surface of the spray coating booth 40 becomes large. The heat quantity becomes large, so the inside of the spray coating booth 40 is cooled. Therefore, even when the spray coating booth 40 is compact, the inside of the spray coating booth 40 is suppressed from reaching a high temperature.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a thermal spraying apparatus that forms a thermal spray film on a workpiece.

  Conventionally, it is known that thermal spraying is used to form a sprayed film of corrosion resistant or high temperature resistant metal, ceramic, or the like on automobile parts such as heat exchangers and gas sensors. As disclosed in Patent Document 1, a thermal spraying apparatus that forms a thermal spray film on a work is constituted by a thermal spray gun installed in a thermal spray booth, a compressor installed outside the thermal spray booth, and a dust collector.

JP 2006257474A

  Since spraying sprays a spray frame of several thousand degrees to 10,000 degrees, the temperature in the spraying booth tends to be high. For this reason, in a structure like patent document 1, in order to enlarge radiation distance, it is thought that the thermal spray booth becomes large-sized so that it may have a wide space, and it prevents the thermal spray booth from becoming high temperature. Further, the compressor blows a large amount of air, dilutes the hot gas in the spraying booth, and lowers the temperature of the spraying booth. Further, the dust collector collects dust scattered in the spraying booth and exhausts a large amount of high-temperature gas to lower the temperature in the spraying booth. Since a large amount of air is blown and exhausted, a large amount of energy is consumed.

  In order to suppress energy consumption, it is conceivable to reduce the air to be blown and exhausted by reducing the size of the thermal spray booth. However, if the thermal spray booth is made smaller, the radiation distance becomes shorter, and therefore the temperature in the thermal spray booth tends to become high. When the temperature in the thermal spray booth becomes high, the heat resistance temperature of the equipment to be used may be exceeded and the thermal spraying device may be broken.

  The present invention was created in view of the above-described problems, and an object of the present invention is to provide a thermal spraying apparatus that can suppress the inside of a thermal spraying booth from becoming high temperature even in a small thermal spraying booth. .

The present invention is a thermal spray apparatus (1) for forming a thermal spray film (53).
The thermal spraying device includes a thermal spray gun (10), a thermal spray booth (40), a compressor (35), and a dust collector (36).
A thermal spray gun injects the thermal spray flame | frame (15) which fuse | melted powder material (11) from the nozzle opening (21) facing a workpiece | work (50). The spray gun sprays a spray frame on the work to form a sprayed film.

The thermal spray booth is cylindrical and has an insertion hole (41) in which a workpiece is installed and a thermal spray gun is inserted.
The compressor blows gas to the inlet (42) in the spraying booth.
The dust collector sucks the gas from the outlet (43) in the spraying booth and exhausts the dust (23) in the exhaust.
The gas flow velocity and the diameter of the spray booth are set so that the airflow flowing from the inlet to the outlet through the spray booth can pass across the spray frame.

  In the thermal spraying apparatus according to the present invention, the airflow from the inlet portion toward the outlet portion can pass through the thermal spray frame. Thereby, since the airflow can pass across the thermal spraying frame, the airflow reaches the exhaust side of the thermal spray gun as a heat source.

  When the airflow reaches the exhaust side, the amount of heat absorbed from the air in the spray booth and the wall surface of the spray booth increases. Since the amount of heat absorption increases, the inside of the thermal spray booth is easily cooled. Therefore, even in a small thermal spraying booth, it is possible to suppress the inside of the thermal spraying booth from becoming high temperature.

The block diagram of the thermal spraying apparatus by 1st Embodiment of this invention. Sectional drawing of the thermal spray gun by 1st Embodiment of this invention. The perspective view of the thermal spray booth by 1st Embodiment of this invention. The block diagram of the thermal spraying apparatus by 2nd Embodiment of this invention. The block diagram of the thermal spraying apparatus of other embodiment. The block diagram of the thermal spraying apparatus of other embodiment.

Hereinafter, a thermal spraying apparatus according to the present invention will be described with reference to the drawings. In the description of the plurality of embodiments and the manufacturing method, the same reference numerals are given to the substantially same configurations as those in the first embodiment. The “present embodiment” includes the first embodiment and the second embodiment. In this embodiment, a plasma spray gun is used as the spray gun.
(First embodiment)

The thermal spraying apparatus 1 by 1st Embodiment is demonstrated with reference to FIGS. 1-3.
With reference to FIG. 1, the structure of the thermal spraying apparatus 1 is demonstrated.
As shown in FIG. 1, the thermal spray apparatus 1 includes a plasma spray gun 10, a work 50, a spray booth 40, an exhaust duct 44, a feeder 31, a power supply device 32, a working gas supply device 33, a cooling device 34, a compressor 35, and a dust collector 36. Is provided.

  As shown in FIG. 2, the plasma spray gun 10 includes a housing 14, an electrode 24, a nozzle 13, and a material port 12.

The housing 14 accommodates the electrode 24 and the nozzle 13.
The electrode 24 includes an anode 16 and a cathode 17. For example, tungsten is used for the electrode 24.
The anode 16 is a positive electrode and is adjacent to the housing 14. The cathode 17 is a negative electrode and is disposed on the inner side of the anode 16 with respect to the radial direction of the housing 14. When electric power is supplied to the electrode 24, the electrode 24 causes an electron to jump out between the anode 16 and the cathode 17, and generates an arc discharge.

  The nozzle 13 is formed between the anode 16 and the cathode 17, and includes a nozzle port 21 at the distal end portion 20 on the distal end side and a working gas inlet 22 at the base portion 18 on the proximal end side. The center of the nozzle port 21 in the radial direction is the nozzle port center O. The nozzle 13 is formed so that the working gas flows from the working gas receiving port 22 to the nozzle port 21.

  The material port 12 is mounted adjacent to the distal end surface 19 outside the housing 14. The supply method is an external supply method in which the powder material 11 is supplied to the thermal spray frame 15 injected from the nozzle port 21 via the material port 12. The material port 12 may be mounted in the housing 14 and an internal supply method may be used.

  The plasma spray gun 10 generates plasma by arc discharge and forms a spray frame 15 in which the powder material 11 is melted by plasma. As the powder material 11, a rod-shaped material may be used to perform low-temperature spraying.

  Further, the plasma spray gun 10 injects the spray frame 15 from the nozzle opening 21 facing the work 50, and sprays the spray frame 15 on the work 50 in the same direction as the lower direction of gravity, thereby forming a spray film 53. Make it possible.

The thermal spray frame 15 is a flow of the thermal spray material which is supplied with the powder material 11 to the plasma ejected from the nozzle port 21 via the material port 12 and is melted and accelerated by the plasma.
The workpiece 50 is disposed on the stage 51 at a position where the film formation surface 52 faces the spray gun 10 in the spray booth 40.

As shown in FIG. 1, the thermal spray booth 40 is installed such that the axial direction of the thermal spray booth 60 is horizontal with respect to the lower side in the gravity direction.
As shown in FIG. 3, the thermal spray booth 40 is cylindrical and has an inclined portion 45, an inlet portion 42, and an outlet portion 43. The thermal spray booth 40 has an insertion hole 41 into which the thermal spray gun 10 is inserted on the side surface, and supports a plate-like stage 51 joined to the inner side surface 48.

  The inclined portion 45 is formed so that the inner side surface 48 facing the thermal spray gun 10 is an inclined surface and is inclined downward from the inlet portion 42 toward the outlet portion 43 in the direction of gravity. Due to the inclined portion 45, the diameter and the area within the diameter increase from the inlet portion 42 to the outlet portion 43. The inclined portion 45 may have a part of the inner side surface 48 that is inclined or stepped.

The inlet portion 42 and the outlet portion 43 include an axis parallel to the axial direction of the thermal spray booth 40 and face each other.
Let the diameter of the inlet part 42 be the inlet diameter D1, and let the diameter of the outlet part 43 be the outlet diameter D2. The outlet diameter D2 is formed to be larger than the inlet diameter D1, that is, D1 <D2. Further, the area within the diameter of the inlet portion 42 is S1, and the area within the diameter of the outlet portion 43 is S2. Since the outlet diameter D2 is larger than the inlet diameter D1, the outlet portion area S2 is formed to be larger than the inlet portion area S1.

  Further, the height from the imaginary line I to the inlet portion 42 that is located below the thermal spray booth 40 and is parallel to the axial direction of the thermal spray booth 40 is H1, and the height from the imaginary line I to the outlet portion 43 is the height. Let H2. The height H1 is formed to be greater than the height H2, that is, a relationship of H1> H2.

  The angle formed by the inclined portion 45 and the perpendicular P of the outlet portion 43 is θ, and the angle θ is formed so that 0 <θ <90. The angle θ is arbitrarily set. It is optimally adjusted by the flow velocity V of the air in the spraying booth 40 and the diameter of the spraying booth.

  The exhaust duct 44 has a cylindrical shape and is connected to the outlet 43 of the thermal spray booth 40 in an L shape. The exhaust duct 44 includes an inner wall 49 that faces the outlet portion 43, an exhaust portion 46 that opens downward in the direction of gravity, and a curved portion 47 that curves from the outlet portion 43 along the exhaust portion 46.

  The distance L1 from the inlet 42 to the nozzle port center O is L1, and the distance from the inner wall 49 to the nozzle port center O is L2. The thermal spray booth 40 and the exhaust duct 44 are formed so that the distance L2 is smaller than the distance L1, that is, L1 <L2.

  The feeder 31 is installed outside the spraying booth 40, connected to the material port 12, and supplies the powder material 11 to the material port 12. Further, the feeder 31 cuts and delivers the powder material 11 entering a disk board (not shown) and supplies the powder material 11.

The power supply device 32 is connected to the electrode 24 with a high-power cable, and supplies the electrode 24 with power capable of converting the working gas into plasma.
The working gas supply device 33 is connected to the working gas inlet 22 of the thermal spray gun 10 and supplies the working gas. The working gas is, for example, argon, helium, hydrogen, or nitrogen.
The cooling device 34 supplies cooling water to the thermal spray gun 10. The supplied cooling water circulates, and the spray gun 10 is cooled by the circulating cooling water.

The compressor 35 is connected to the inlet 42 of the thermal spray booth 40 by piping and uses air as a gas. The compressor 35 blows air from the inlet 42 to the outlet 43.
The dust collector 36 is connected to an exhaust unit 46 by piping, sucks air in the thermal spray booth 40 from the exhaust unit 46, and collects the dust 23 that is the powder material 11 that has not contributed to the film formation. The dust 23 is the powder material 11 that has not been melted by plasma or has been solidified by cooling the powder material 11 melted by plasma.

The compressor 35 and the dust collector 36 form an air flow that is a flow of air that flows from the inlet portion 42 toward the outlet portion 43.
The air velocity in the spraying booth 40 and the diameter of the spraying booth are set so that the airflow can pass across the spraying frame 15. The air flow also dilutes the air in the thermal spray booth 40 from the inlet portion 42 to the outlet portion 43.

The airflow is turbulent and the Reynolds number Re exceeds 2300, that is, Re> 2300. The Reynolds number Re is represented by the following formula (1), for example. The flow velocity V of the inlet portion 42, the diameter of the inlet portion 42 are D, and the air dynamic viscosity ν.
Re = (V × D) / ν (1)

  The flow velocity V and the diameter D are adjusted by the compressor 35, the dust collector 36, the spraying booth 40, and the exhaust duct 44 so as to be turbulent depending on the use environment such as gas, temperature or pressure in the spraying booth 40 or spraying conditions.

  Since the airflow is turbulent, it can pass across the thermal spray frame 15. Since the turbulent flow is a flow having a large inertia force, the turbulent flow tries to push in the direction from the inlet portion 42 toward the outlet portion 43. Accordingly, the airflow can pass through the spray frame 15 having a high flow velocity without changing the speed.

The operation of the thermal spraying apparatus 1 will be described.
The working gas is supplied from the working gas supply device 33 to the working gas inlet 22 of the spray gun 10. Further, the power supply device 32 supplies power to the electrode 24, and electrons are ejected from the electrode 24 toward the vicinity of the nozzle port 21 to generate arc discharge.

  By the arc discharge, the working gas is ionized to become plasma, and the plasma is ejected from the nozzle port 21. At the same time, the powder material 11 supplied from the feeder 31 is supplied via the material port 12. The powder material 11 to which the plasma to be injected is supplied is melted to form a thermal spray frame 15.

The thermal spray frame 15 is sprayed on the workpiece 50, and a thermal spray film 53 is formed. When the sprayed film 53 is formed, the airflow passes through the sprayed frame 15. The passing air stream carries the dust 23 to the exhaust part 46 via the outlet part 43. The dust collector 36 collects the carried dust 23. Further, the air flow passes through the thermal spray booth 40 from the inlet portion 42 toward the outlet portion 43 to dilute the high-temperature air in the thermal spray booth 40, thereby lowering the temperature of the thermal spray booth.
(effect)

  In the present embodiment, since the airflow can pass across the thermal spraying frame 15, the airflow reaches the exhaust side of the thermal spray gun 10 serving as a heat source. Further, since the distance L1 in the spraying booth 40 is smaller than the distance L2, the airflow easily reaches the exhaust side of the spraying gun 10.

  When the airflow reaches the exhaust side, the amount of heat absorbed from the air in the spray booth 40 and the wall surface of the spray booth increases. Since the amount of heat absorption increases, the inside of the spraying booth 40 is easily cooled. Thereby, it can suppress that the inside of the thermal spray booth 40 becomes high temperature. Therefore, even when the thermal spray booth 40 is downsized, it is possible to prevent the thermal spraying apparatus from being broken by exceeding the heat resistance temperature of the thermal spraying apparatus.

  In the thermal spraying using plasma, since the thermal spray frame is hot among other thermal sprays, the inside of the thermal spray booth 40 is likely to become hot due to radiation. Therefore, in the thermal spraying using plasma, the effect of suppressing the high temperature in the thermal spray booth is particularly exhibited.

  Since the thermal spray booth 40 has the inclined portion 45, the dust 23 falling on the inner side surface 48 due to gravity tends to flow to the exhaust portion 46 before the dust 23 accumulates on the inner side surface 48. As a result, the falling dust 23 flows to the exhaust part 46, thereby preventing the dust 23 from accumulating on the inner surface 48. Moreover, since the exhaust part 46 of the exhaust duct 44 is opened downward in the direction of gravity, the dust 23 can easily flow to the dust collector 36 due to gravity, and the collection efficiency of the dust collector 36 is improved.

  Since the diameter and area of the thermal spray booth 40 are expanded from the inlet portion 42 to the outlet portion 43 of the thermal spray booth 40, vortices are likely to be generated in the thermal spray booth. The generated vortex winds up the dust 23 accumulated in the spraying booth, and the dust 23 easily reaches the exhaust part 46. Thereby, the collection | recovery efficiency of the dust collector 36 improves.

(Second Embodiment)
With reference to FIG. 4, the structure of the thermal spraying apparatus 2 by 2nd Embodiment is demonstrated. The second embodiment is the same as the first embodiment except that the exhaust duct 44 is not provided. A dust collector 36 is connected to the outlet 43, and the shape of the spraying booth is different. The rest is common.

  As shown in FIG. 4, the thermal spray booth 60 is cylindrical with the axial direction of the thermal spray booth 60 being set horizontally with respect to the lower side in the direction of gravity. The thermal spray booth 60 is formed so that the axial length is uniform.

The distance from the inlet portion 42 to the nozzle port center O is L1, and the distance from the outlet portion 43 to the nozzle port center O is L3. Further, the thermal spray booth 40 is formed such that the distance L1 is smaller than the distance L3, that is, L1 <L3.
(effect)

  Also in the second embodiment, since the airflow can pass through the thermal spray frame 15, the airflow reaches the exhaust side of the thermal spray gun 10 serving as a heat source. In addition, since the distance L1 in the thermal spray booth 40 is smaller than the distance L3, the airflow can easily reach the exhaust side of the thermal spray gun 10, and the same effect as in the present embodiment can be achieved.

(Other embodiments)
(A) The thermal spray gun 10 may be formed by subjecting the thermal spray frame 15 to high speed flame spraying (so-called HVOF thermal spraying), gas flame thermal spraying, arc thermal spraying, or explosive thermal spraying. The same effect as this embodiment is produced.

(A) The shapes of the thermal spray booth 40 and the exhaust duct 44 are not limited to a cylindrical shape. A polygonal cylinder may be used. In addition, the thermal spray booth 40 is not limited to a small size, and the gas flow velocity V and the diameter D may be set so that an air flow can pass across the thermal spray frame 15 with respect to a large thermal spray booth. Regardless of the shape and size of the thermal spray booth 40, the thermal spray booth similar to that of the present embodiment has an effect of suppressing a high temperature.
(C) The gas blown by the compressor 35 is not limited to air, and dry air or nitrogen may be used. The same effect as this embodiment is produced.

(D) As shown in FIG. 5, the thermal spray booth 61 may have the axial direction of the thermal spray booth 61 in the same direction as the lower part of the gravity direction. Further, the plasma spray gun 10 may be installed horizontally and the sprayed film 53 may be formed. The same effect as this embodiment is produced.
(E) As shown in FIG. 6, the thermal spray booth 62 may have the inclined portion 45 formed inside the thermal spray booth 62. The same effect as this embodiment is produced.
As mentioned above, this invention is not limited to such embodiment, In the range which does not deviate from the meaning of invention, it can implement with a various form.

10 ... Spray gun (plasma spray gun),
11 ... Powder material,
15 ... sprayed frame,
21 ... Nozzle opening,
35 ・ ・ ・ Compressor,
36 ・ ・ ・ Dust collector,
40 ... spraying booth,
41 ... insertion hole,
42 ・ ・ ・ Inlet part,
43 ... Exit part,
50 ・ ・ ・ Work,
53 ... Sprayed film.

Claims (7)

A thermal spray frame (15) in which the powder material (11) is melted is sprayed from a nozzle port (21) facing the work (50), and the thermal spray frame is sprayed onto the work to form a thermal spray film (53). A spray gun (10)
Compressor (35) which is cylindrical and has a workpiece installed therein, and has an insertion hole (41) into which the spray gun is inserted, and a gas blower to the inlet (42) in the spray booth )When,
A dust collector (36) for sucking the gas from an outlet (43) in the spraying booth and collecting dust (23) in the exhaust;
With
The thermal spraying apparatus in which the flow velocity of the gas and the diameter of the thermal spray booth are set so that the airflow flowing from the inlet to the outlet through the thermal spray booth can pass across the thermal spray frame. The thermal spray booth is installed horizontally,
An exhaust duct (44) connected to the outlet portion parallel to the direction of gravity and L-shaped and having an exhaust portion (46) connected to the dust collector and an inner wall (49) facing the outlet portion;
The thermal spraying device according to claim 1, wherein the exhaust portion is opened downward in a gravitational direction.   In the thermal spray booth and the exhaust duct, the distance (L1) from the inlet portion to the nozzle port center (O), which is the center in the radial direction of the nozzle port, is the distance (L2) from the inner wall to the nozzle port center. The thermal spraying device according to claim 2, wherein the thermal spraying device is formed so as to be smaller.   The thermal spraying device according to claim 3, wherein the thermal spray booth is formed such that an area (S2) of the outlet portion is larger than an area (S1) of the inlet portion.   The thermal spraying device according to claim 4, wherein the thermal spray booth has an inclined portion (45) facing the thermal spray gun and inclined downward in the direction of gravity from the inlet portion toward the outlet portion.   The said thermal spray booth is formed so that the distance from the said inlet part to the said nozzle mouth center (O) may become smaller than the distance (L3) from the said outlet part to the said nozzle mouth center. Spraying equipment.   The thermal spraying device according to claim 1, wherein the thermal spray gun generates plasma by arc discharge and sprays the thermal spray frame in which the powder material is melted by the plasma.

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