JPS6224135B2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to an electrostatic powder spraying device.

A main object of the present invention is to provide an electrostatic spraying device that can charge coloring powder simply and effectively, and sufficiently charge the entire surface of the particles.

The object is achieved by an electrostatic powder spraying device according to the invention, characterized in that it has a plurality of twisted charging ducts, the charging ducts being elongated and made of non-conductive material, such as plastic. The outer periphery of the material is covered with a conductive layer, and this conductive layer is connected to a lead wire for the purpose of grounding, for example, so that the powder does not pass through the charging duct when using the powder spraying device. It comes into contact with the inner wall of the duct and becomes electrically charged.

Next, embodiments of the present invention will be described with reference to the accompanying drawings.

The electrostatic powder spraying device 1 according to the present invention is particularly suitable for powder spraying, and is preferably held and operated by a coating robot. This electrostatic powder spraying device 1 consists essentially of a front member 4, a central member 3, and a rear member 2.
It is composed of three members.

First, the rear member 2 is a connecting member that is connected to a hose for transferring coloring powder from a paint bottle.

The central member 3 charges and transports the coloring powder therethrough. The front member 4 is a spray nozzle.

The central member 3 is provided with a tube 5, in which a charging duct 6, which is a plurality of spirally twisted elongated tubes, is provided.
are arranged annularly around the core 11.
These charging ducts 6 are preferably made of plastic or other non-conductive material.

As can be seen from FIG. 3, these charging ducts 6 are each coated with a conductive layer 7, such as a metal layer. At the rear end of the charging duct 6, a conductor 8 is provided, one end of which is connected to the conductive layer 7 by, for example, solder 9, and the other end of the conductor 8 converges and passes through the opening of the tube 5. A common conducting wire 10 is led out to the outside of the pipe 5 and connected to ground or a power source. The ends of the charging duct 6 are fitted into circular cores, that is, a rear core 11 and a front core 12, respectively.
Around both cores 11 and 12, there are a plurality of through holes 13 which hold respective charging ducts 6 which are annularly spaced apart. In the center of the rear core 11 is a cone 14 with its tip facing away from the transport direction, which serves as a distributor for the incoming powder. A sleeve 15 is attached to the rear end of the tube 5, and a connecting portion 16 is formed at one end of the sleeve 15 to interconnect the powder spraying device 1 and a hose for transferring coloring powder from a paint hopper. has been done.

On the other hand, a spray nozzle 1 is installed at the other end of the tube 5.
7. A front member 4 consisting of a connecting pipe 18 and a throttle sleeve 19 is attached. The rear end of this aperture sleeve 19 is connected to the charging duct 6 via a connecting sleeve 20, and the front end surrounds the end of the tube 5 and directs the charged powder to the center line of the powder spraying device 1 or nozzle 17. It is formed in a conically tapered passageway 21 which leads to a conically tapered passage. Connecting pipe 18
A rear end portion of the aperture sleeve 19 is housed and held. The connecting ring 22 is screwed to the front end of the pipe 18, supports the spray nozzle 17, and has a rear end connected to a hose 24 for supplying a gas such as air.
An axial flow duct 23 is formed in which the gas from the hose 24 flows.

The spray nozzle 17 has a sleeve 2 having an end wall 26 at the front end and an opening 27 at the center.
5. The opening 2 has a chamfered edge 27A on the outside and a stepped shoulder 27B on the inside. The diffusion chamber 28 is constituted by a tubular member made of an air-permeable porous material manufactured by, for example, a sintering method, and the front end of the diffusion chamber 28 is fitted into the stepped shoulder 27B. Further, the rear end of the diffusion chamber 28 is fitted into the connecting ring 22 and comes into contact with the front end of the connecting pipe 18 . The gas body introduced at overpressure through the axial flow duct 23 of the coupling ring 22 flows into the chamber 29 formed between the nozzle 17 and the diffusion chamber 28.
and is then sprayed through the small holes in the porous material forming the diffusion chamber 28 and into the front portion of the through duct 30 of the front member 4. At this time, an overpressure is created in the front part of the nozzle 17, so that the powder and the gas stream are expanded and compressed into a mist when ejected from the nozzle 17. Furthermore, the ejection speed of the powder can be adjusted by changing the overpressure.

Next, the operation of the above powder spraying device will be explained.

As mentioned above, the rear end 16 of the powder spraying device 1 is connected to the paint hopper etc. by a hose. The coloring powder is transported by the air stream through the rear part 2 of the powder spraying device 1, diffused outwardly by the cone 14, and passed through the through hole 13 of the rear core 11 and the charging duct 6. be transported. The charging duct 6 is connected to earth via conductors 8, 10 or, for example, to a high-voltage power supply;
Since the particles are spirally wound, the powder swirls in the charging duct 6 during transfer, and the entire surface of the particles comes into contact with the inner wall of the charging duct 6. Therefore, the powder is sufficiently charged when it is discharged from the charging duct 6. The powder flow after flowing out from the charging duct 6 is throttled by the throttle sleeve 19, and then passed through the connecting pipe 18.
The water passes through the through duct 30 and is sent to the nozzle 17. This powder is mixed with air flowing in through the hose 24 and the diffusion chamber 28 and compressed so that it expands sufficiently when it is ejected from the nozzle 17. Therefore, the powder is dispersed in the form of a mist, and since it is electrically charged, it reaches the object, adheres to it, and becomes colored. Furthermore, parts of the object that are difficult for the fog to reach are also covered with powder.

Figures 5 and 6 show other embodiments of the present invention, and since the structure of the powder spraying device shown here is similar to that described above, the parts common to the two embodiments are Similar reference numbers have been provided.

However, unlike the powder spraying device described above, the powder spraying device shown in FIGS. 5 and 6 is provided with a charging duct 6' having an irregularly bent portion instead of the spirally curved duct. and extend in various different planes, as illustrated in FIGS. 5 and 6, respectively.

The operation of the powder spraying device shown in FIGS. 5 and 6 is similar to the powder spraying device described above. That is, the powder guided through the powder spraying device and the charging duct 6' swirls within the charging duct 6' and contacts its inner wall to effectively prevent the powder from being transported through the charging duct 6'. is charged with electricity.

Although the apparatus according to the present invention has been described above, the present invention is not limited to the embodiments described and illustrated above, and may be modified in any way without exceeding the scope of the claims. .

[Brief explanation of the drawing]

FIG. 1 is a perspective view of a powder spraying device according to the present invention;
FIG. 2 is a partial cross-sectional view of the rear end of the powder spraying device, FIG. 3 is a diagram showing a transfer charging duct that constitutes a part of the powder spraying device and a conducting wire connected to the charging duct, and FIG. 4 is a partial sectional view of the front end of the powder spraying device, FIG. 5 is another embodiment of the present invention, and a partial sectional view of the rear end and FIG. 6 are shown in FIG. FIG. 3 is a partial cross-sectional view of the front end of the powder spraying device. 1... Powder spraying device, 2... Rear member, 3...
Central member, 4... Front member, 5... Tube, 6, 6'
... Charged duct, 7 ... Conductive layer, 8, 10 ... Conductor wire, 11, 12 ... Core, 13 ... Through hole, 14 ...
... Cone, 15 ... Sleeve, 17 ... Spray nozzle, 19 ... Restriction sleeve, 21 ... Cone, 23 ... Axial flow duct, 28 ... Diffusion chamber.

Claims (1)

[Scope of Claims] 1. An electrostatic powder spraying device in which powder flowing from one end of a tube 5 is charged and sprayed to the outside from a spray nozzle 17 provided at the other end of the tube 5, comprising: 5 has a plurality of elongated charging ducts 6 made of non-conductive material inside, and each of these charging ducts 6
The outer periphery is covered with a conductive layer 7 and twisted so that the powder being transferred comes into contact with the inner wall, and a conductive wire 8 whose end is connected to ground or a power source is connected to the conductive layer 7. An electrostatic powder spraying device characterized by: 2. The electrostatic powder spraying device according to claim 1, wherein the charging duct 6 is disposed around the outer periphery of a conical core 11 provided at the inlet side end of the tube 5. 3. The electrostatic powder spraying device according to claim 1 or 2, wherein the pipe 5 has a throttle sleeve 19 between the charging duct 6 and the spray nozzle 17.