JP2017202468A - Electrostatic atomization device and electrostatic atomization method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrostatic atomization device and an electrostatic atomization method capable of providing high liquid coating efficiency even when coating liquid on an electric field concentration part of a coating object.SOLUTION: An electrostatic atomization device 10 of the present invention is the electrostatic atomization device 10 for atomizing liquid on a coating object 40 by separating the liquid in an electrification state from a nozzle 22 of a liquid atomization part 20 by electrostatic force generated by an impression of voltage, and comprises the liquid atomization part 20 having the nozzle 22, first voltage impression means 50 for impressing the voltage between the liquid atomization part 20 and the coating object 40 and second voltage impression means (second electric wiring 42a) for setting a member 30 as the same pole as the coating object 40 by impressing the voltage between the liquid atomization part 20 and a conductive material or the member of a semiconductive material arranged in the vicinity of an electric field concentration part (an end part 40a) of the coating object 40.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an electrostatic spraying apparatus and an electrostatic spraying method.

  Conventionally, when an object has a recess using an electrostatic spray technology that discharges a charged liquid from a cylinder and forms a large number of fine droplets by a repulsive force due to electrostatic force and supplies the object to the object, An electrostatic spraying device for efficiently forming a liquid film on the inner surface of a recess is known (see Patent Document 1).

JP2015-192961A

When a liquid such as a paint is applied to an object to be coated using such an electrostatic spray technique, for example, a high application efficiency close to 100% can be obtained.
However, for example, it has been found that when a liquid is applied to an electric field concentration portion such as an end portion of a stick-shaped object, the liquid application efficiency is lowered.

  The present invention has been made in view of such circumstances, and an electrostatic spraying device and a static device that can obtain high liquid application efficiency even when liquid is applied to an electric field concentration portion of an object to be coated. An object is to provide an electrospraying method.

The present invention is grasped by the following composition in order to achieve the above-mentioned object.
(1) The electrostatic spraying device of the present invention is an electrostatic spraying device that sprays the liquid onto the object to be coated by detaching the liquid from the nozzle of the liquid spraying portion in a charged state by electrostatic force generated by applying a voltage. The liquid spraying section having the nozzle, first voltage applying means for applying the voltage between the liquid spraying section and the object to be coated, and an electric field concentration section of the liquid spraying section and the object to be coated. A second voltage applying unit configured to apply the voltage between members of a conductive material or a semiconductive material disposed in the vicinity so that the member has the same polarity as the object to be coated;

(2) In the configuration of (1), the second voltage application unit is connected in the middle of the first electrical wiring from the first voltage application unit to the object to be coated, and the first voltage application unit Second electrical wiring is provided so that a voltage applied to the object can be applied to the member, and the second voltage application means makes the member the same potential as the object. .

(3) In the configuration of the above (1) or (2), the member is a rod-shaped electrode member having one end disposed in the vicinity of the electric field concentration portion, and is opposite to the one end of the rod-shaped body. The length to the other end is a length at which the other end is located outside the spray range of the liquid when the one end is disposed in the vicinity of the electric field concentration portion.

(4) In the structure according to any one of (1) to (3), the member is positioned such that a part of the member is positioned within a range of 20 mm or less from the electric field concentration portion of the object to be coated. Is provided.

(5) The electrostatic spraying method of the present invention is an electrostatic spraying method in which the liquid is discharged from the nozzle of the liquid spraying portion in a charged state by electrostatic force generated by application of a voltage, and the liquid is sprayed on the object to be coated. Then, the liquid is sprayed onto the object to be coated in a state where a conductive material or a semiconductive material having the same polarity as the object to be coated is disposed in the vicinity of the electric field concentration portion of the object to be coated.

(6) In the configuration of (5), the potential of the member is set to the same potential as the potential of the article to be coated.

(7) In the configuration of the above (5) or (6), the same first object to be coated is used as the member.

(8) In the configuration of (7), a plurality of the first objects to be coated are used as the member.

(9) In the configuration of (7) or (8), the electric field concentration portion of the first object to be coated is disposed in the vicinity of the electric field concentration portion of the object to be coated.

(10) In the configuration of (7), the electric field concentration portion of the object to be coated and the first object to be coated is an end, and the first object to be coated is relative to the end of the object to be coated. The first coated object is arranged in the vicinity of the coated object so as to face each other.

(11) In the configuration of (5) or (6), the member is an electrode member different from the object to be coated.

(12) In any one of the configurations (5) to (11), the article to be coated and the member are rod-shaped bodies.

  ADVANTAGE OF THE INVENTION According to this invention, even when applying a liquid to the electric field concentration part of to-be-coated object, the electrostatic spraying apparatus and electrostatic spraying method which can obtain the coating efficiency of a high liquid can be provided.

It is a perspective view of the electrostatic spraying apparatus of embodiment which concerns on this invention. It is sectional drawing which showed only the liquid spray part of embodiment which concerns on this invention. It is an expanded sectional view of the front end side of the liquid spraying part of FIG. It is a figure for demonstrating the spraying state etc. of the liquid at the time of spraying a liquid in the state which does not arrange | position the member made into the same polarity as the to-be-coated object of embodiment which concerns on this invention, (a) It is a figure which shows the place which is spraying, (b) is a figure which shows the state of the electric field of the edge part of to-be-coated article. It is a schematic diagram for demonstrating the cause used as the state of Fig.4 (a). FIG. 6 is a diagram for explaining a liquid spraying state and the like when the liquid spraying is performed in a state where a member having the same polarity as that of the workpiece described with reference to FIG. ) Is a diagram showing a state where a liquid is sprayed, and (b) is a diagram showing electric field states of the article to be coated 40 and the member 30 with equipotential lines. In the electrostatic spraying apparatus according to the embodiment of the present invention, a member having the same polarity as an object to be coated is a first object to be coated that is the same as the object to be coated, and a perspective view showing a case where a plurality of first objects to be coated are used. FIG. It is a figure which shows the state of the electric field when the edge part of the member of embodiment which concerns on this invention is not tapering.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention (hereinafter referred to as embodiments) will be described in detail with reference to the accompanying drawings. Note that the same number is assigned to the same element throughout the description of the embodiment.

  Unless otherwise specified, expressions such as “front (end)” and “front (direction)” indicate the spray direction side of the liquid in each member, etc., and “rear (end)” or “rear (direction)”. The expression "" represents the opposite side of the liquid spraying direction in each member or the like.

FIG. 1 is a perspective view of an electrostatic spray device 10 according to an embodiment of the present invention.
As shown in FIG. 1, the electrostatic spraying device 10 includes a liquid spraying unit 20 having a nozzle 22, and a first voltage applying unit 50 (voltage power source) that applies a voltage between the liquid spraying unit 20 and the object to be coated 40. And a second voltage applying means comprising a second electric wiring 42a that applies a voltage between the liquid spraying part 20 and the member 30 so that the member 30 has the same polarity as the article 40 to be coated.

  In the present embodiment, the first electric wiring 42 from the first voltage applying unit 50 is directly connected to the article 40, but the first electric wiring from the first voltage applying unit 50 is shown. 42 is connected to a holder or the like that holds the object to be coated 40, and the object to be coated 40 is held in the holder or the like so that the object to be coated 40 is electrically connected to the first voltage applying means 50. Also good.

Moreover, in this embodiment, the electrostatic spraying apparatus 10 has the earth | ground means 60 connected to the 1st electrical wiring 42 connected to the to-be-coated object 40 from the 1st voltage application means 50, and the to-be-coated object 40 Is to be grounded.
The grounding means 60 is not an indispensable requirement, but since the workpiece 40 may be touched by an operator, the grounding means 60 is provided from the viewpoint of safety to ground the coating object 40. It is preferable.

(Liquid spray part)
FIG. 2 is a cross-sectional view showing only the liquid spray unit 20, and illustrates a state in which a liquid such as paint is sprayed from the liquid spray unit 20 as will be described later.

  As shown in FIG. 2, the liquid spray unit 20 includes a body part 21 made of an insulating material in which a liquid channel 21 b having a liquid supply port 21 a to which a liquid is supplied is formed, and a through-hole serving as a liquid flow of the body part 21. A nozzle 22 provided at the tip of the body portion 21 so as to communicate with the passage 21b, and a mandrel 23 made of a conductive material disposed in the liquid flow path 21b of the body portion 21 and in the through hole of the nozzle 22. Yes.

The body portion 21 is provided with a hole portion 21c communicating with the liquid channel 21b in order to take out the mandrel 23 to the rear end side, and a gap between the mandrel 23 is sealed in the hole portion 21c. A seal member 24 is provided to prevent liquid from leaking.
In this embodiment, an O-ring is used as the seal member 24. However, the O-ring is not limited to the O-ring, and any member that can be sealed may be used.

  And, at the rear end of the mandrel 23 located on the rear end side of the body portion 21 through the hole portion 21c, a knob portion 23a made of an insulating material is provided and provided so as to penetrate almost the center of the knob portion 23a. An electrical wiring connection portion 23b made of the conductive material thus provided is provided.

  As shown in FIG. 1, the electrical wiring 41 from the first voltage applying means 50 is connected to the electrical wiring connecting portion 23 b, and the electrical wiring connecting portion 23 b is brought into contact with the mandrel 23. The electrical wiring connection portion 23b is electrically connected.

  In this embodiment, the mandrel 23 is an electrode on the liquid spray unit 20 side. However, for example, the nozzle 22 of the liquid spray unit 20 is made of a conductive material, and the first voltage applying unit 50 is connected to the nozzle 22. The electrical wiring 41 may be connected, and the nozzle 22 may be an electrode on the liquid spray unit 20 side.

  As shown in FIG. 2, a female screw structure 21e for screwing and connecting the knob portion 23a is provided on the inner peripheral surface of the rear end opening 21d of the body portion 21, while the tip of the knob portion 23a is provided. A male screw structure 23c is provided on the outer peripheral surface.

Therefore, the mandrel 23 is removably attached to the body part 21 by screwing the male screw structure 23c on the outer peripheral surface of the tip of the knob 23a into the female thread structure 21e of the rear end opening 21d of the body part 21.
Further, the mandrel 23 can be moved in the front-rear direction by adjusting the screwing amount of the knob 23a, and the position of the distal end surface 23d of the mandrel 23 can be adjusted in the front-rear direction.

Here, in general, the nozzle for spraying the liquid of the electrostatic spraying device is a fine liquid passage having a small diameter of the through hole through which the liquid flows.
This is presumably because a stable atomization state of the liquid cannot be obtained when the opening diameter at the tip of the nozzle from which the liquid flows is large.
For example, although depending on the viscosity of the liquid, in the case of a low-viscosity liquid, the opening diameter at the tip of the nozzle is generally less than 0.1 mm.

  For this reason, as soon as the liquid dries, the opening at the tip of the nozzle is clogged. However, since the opening diameter is small, there is a problem that it is difficult to eliminate this clogging.

However, the reason will be explained later. However, by using the mandrel 23, it has been found that the atomization can be favorably atomized even when the opening diameter at the tip of the nozzle is larger than that in the prior art. The opening diameter of the opening 22b at the tip of the nozzle 22 of the present embodiment is a large opening diameter of 0.2 mm.
As a result, the frequency of occurrence of clogging can be greatly reduced.

  The opening diameter of the opening 22b of the nozzle 22 is not limited to 0.2 mm. In the embodiment using the mandrel 23, there is no problem even if the opening diameter is about 1.0 mm.

  The opening diameter of the opening 22b of the nozzle 22 is preferably 0.1 mm or more, more preferably 0.2 mm or more, more preferably 0.2 mm, considering that clogging is less likely to occur and cleaning is possible even when clogging occurs. It is more preferable to make it larger.

  On the other hand, the opening diameter of the opening 22b of the nozzle 22 is preferably 1.0 mm or less, more preferably 0.8 mm or less, and even more preferably 0.5 mm or less in consideration of the stability of atomization.

Moreover, in this embodiment, since the mandrel 23 can be moved in the front-rear direction as described above, the clogging can be eliminated by moving the mandrel 23 even if clogging occurs.
Further, since the inner diameter of the through hole of the nozzle 22 is large enough to allow the mandrel 23 to be disposed, the mandrel 23 can be removed and a large amount of washing liquid can be flowed for washing.

  FIG. 3 is an enlarged view in which the distal end side of the liquid spraying part 20 is enlarged. FIG. 3A is a case where the distal end surface 23d of the mandrel 23 is located rearward, and FIG. This is a case where the distal end surface 23d of the mandrel 23 is located in front of the state of (a).

  As shown in FIG. 3A, the nozzle 22 has a tapered inner diameter portion (refer to the range W1) having a taper angle α that becomes smaller in taper toward the opening portion 22b. Has a tapered portion (see range W2) having a taper angle β of which the outer diameter becomes smaller toward the distal end surface 23d.

The taper angle α of the tapered inner diameter portion of the nozzle 22 is set larger than the taper angle β of the tapered portion of the mandrel 23.
Further, the diameter of the front end surface 23d of the mandrel 23 is smaller than the opening diameter of the opening 22b of the nozzle 22, but the tapered portion of the mandrel 23 gradually increases in diameter toward the rear end side. Thus, the nozzle 22 is formed to have a portion having a diameter larger than the opening diameter of the opening 22b.

  As described above, by forming the tip end side of the nozzle 22 and the mandrel 23, as can be seen by comparing FIG. 3A and FIG. The width of the gap formed by the mandrel 23 can be adjusted, and the amount of liquid exiting from the opening 22b of the nozzle 22 can be adjusted.

Further, by moving the mandrel 23 further forward than in the state shown in FIG. 3B, the mandrel 23 can abut against the inner peripheral surface of the nozzle 22 to close the opening 22 b of the nozzle 22. It is.
Therefore, it is possible to prevent the liquid in the nozzle 22 from being dried by blocking the opening 22b of the nozzle 22 with the mandrel 23 in a state where the liquid such as paint is not sprayed, and to suppress the clogging of the nozzle 22. it can.

(Basic spray state of liquid)
Next, with reference to FIG. 2, first, a basic state in which the liquid is sprayed from the liquid spraying unit 20 will be described, and then the member 30 having the same polarity as the article to be coated 40 is not disposed. The liquid spray state, the liquid spray state when the member 30 having the same polarity as the article to be coated 40 is disposed, and the like will be described.

  The liquid supplied to the liquid supply port 21a of the body part 21 is supplied to the tip end side of the nozzle 22, and the first voltage applying means 50 (see FIGS. 1 and 2) causes the article to be coated 40, the mandrel 23, It is pulled forward by the electrostatic force accompanying the voltage applied during the period, and it is separated and atomized forward.

  The state where the liquid is detached and atomized will be described more specifically. The liquid is moved forward with respect to the adhesion force due to the surface tension and the viscosity on the distal end surface 23 d of the liquid mandrel 23 and the outer peripheral edge 22 a of the nozzle 22. As shown in FIG. 2, the electrostatic force to be pulled balances the liquid supplied to the tip side of the nozzle 22 so that a tailor cone 80 having a conical shape at the tip is formed.

The tailor cone 80 is formed into a conical shape by separating the positive / negative charges in the liquid by the action of an electric field, and deforming the meniscus at the tip of the nozzle 22 charged with an excess charge.
Then, the liquid is pulled straight from the tip of the tailor cone 80 by electrostatic force, and then the liquid is sprayed by electrostatic explosion.

  The liquid to be sprayed, that is, the liquid that has been separated from the nozzle 22 into liquid particles, has a drastically larger area in contact with air than the state before separation, and thus the evaporation of the solvent is promoted. The distance between the charged electrons is reduced as the gas is evaporated, electrostatic repulsion (electrostatic explosion) occurs, and the liquid particles are further divided into small liquid particles.

When this splitting occurs, the surface area in contact with air increases compared to before splitting, so that the evaporation of the solvent is promoted, an electrostatic explosion occurs as described above, and a liquid with a small particle size. Split into particles.
The liquid is atomized by repeating such electrostatic explosion.

Here, in the present embodiment, a mandrel 23 is provided in the nozzle 22.
Assuming that the mandrel 23 is not provided as in the conventional electrostatic spraying device, the portion to which the liquid can adhere is only the outer peripheral edge 22a of the tip of the nozzle 22.

  When the opening diameter of the opening 22b of the nozzle 22 is increased in such a state, the liquid can be attached only to the outer peripheral edge 22a of the tip of the nozzle 22. This makes it impossible to form a clean tailor cone 80 or to maintain the tailor cone 80 itself, so that the stability of the liquid particles detaching from the nozzle 22 (stability of particle size, number, charged state, etc.) is obtained. As a result, it is surmised that stable atomization of the liquid cannot be achieved.

On the other hand, in this embodiment, the mandrel 23 is disposed in the nozzle 22, and the liquid adheres not only to the outer peripheral edge 22 a of the nozzle 22 but also to the distal end surface 23 d of the mandrel 23.
Therefore, even if the opening diameter of the opening 22b of the nozzle 22 is large, the tip end surface 23d of the mandrel 23 to which the liquid can adhere is present at the center of the opening 22b, so that a stable tailor cone 80 can be formed. It is thought that stable atomization is possible.

  If the distal end surface 23d of the mandrel 23 protrudes too far forward from the outer peripheral edge 22a of the nozzle 22 (that is, the distal end surface of the opening 22b of the nozzle 22), the electric field is less likely to act on the liquid coming out of the nozzle 22, while the mandrel If the front end surface 23d of the nozzle 23 is retracted too far backward from the front end surface of the opening 22b of the nozzle 22, the state is the same as when there is no portion where the liquid can adhere to the central portion of the opening 22b.

  From this, the position of the tip surface 23d of the mandrel 23 is in the front-rear direction along the central axis of the mandrel 23 with respect to the tip surface of the opening 22b of the nozzle 22 in the state where the liquid is sprayed. It is preferably located within 10 times the opening diameter of the opening 22b at the tip, more preferably within 5 times, and even more preferably within 3 times.

  For example, in this embodiment, the opening diameter of the opening 22b of the nozzle 22 is 0.2 mm, and when the electrostatic force is not taken into consideration, the liquid discharged from the opening 22b of the nozzle 22 has a diameter of about It comes out to be a hemisphere of 0.2 mm.

  Then, the tip of the mandrel 23 reaches the vicinity of the opening 22b of the nozzle 22 so that a conical tailor cone 80 can be formed by an electric field (electrostatic force) acting on the liquid coming out of the tip of the nozzle 22. Therefore, it is preferable to be located within 2 mm forward (outward direction) from the front end surface of the opening 22b of the nozzle 22, while acting on the adhesion of the liquid. In addition, it is preferable that the tip of the mandrel 23 be positioned within 2 mm behind (in the retracting direction) from the tip surface of the opening 22 b of the nozzle 22.

As described above, by providing the mandrel 23, stable atomization of the liquid can be performed even if the opening diameter of the opening 22b of the nozzle 22 is increased.
For this reason, the opening diameter of the opening part 22b of the nozzle 22 can be made into a large opening diameter which can suppress clogging.
Further, since the opening diameter of the opening 22b of the nozzle 22 can be increased, the nozzle 22 can be easily manufactured by machining.

  In the present embodiment, the tip of the mandrel 23 is shown as a flat flat surface as the tip surface 23d. However, the tip of the mandrel 23 is not necessarily a flat flat surface, and the stable tailor cone 80 is formed. Therefore, for example, the tip of the mandrel 23 may be a curved surface protruding toward the front side like an R shape.

  The liquid sprayed from the liquid spraying part 20 (nozzle 22) in this way is atomized while repeating electrostatic explosion, and since the atomized liquid is charged, the liquid is applied by the first voltage application means 50. The object 40 is attracted to the side of the object to be coated 40, which is in a state of a different polarity with respect to the spray unit 20, and is applied to the object to be coated 40.

  Next, about the spray state of the liquid when not arranging the member 30 having the same polarity as the article to be coated 40, the spraying state of the liquid when arranging the member 30 having the same polarity as the article to be coated 40, etc. While performing the description, the configuration and the like of the liquid spray unit 20 of the present embodiment will be described.

(When member 30 is not arranged)
FIG. 4 is a diagram for explaining a liquid spraying state and the like when the liquid is sprayed in a state where the member 30 having the same polarity as the workpiece 40 described with reference to FIG. 1 is not disposed. 4A is a diagram showing a state where the liquid is sprayed, and FIG. 4B is a diagram showing the state of the electric field of the end portion 40a of the article 40 by equipotential lines.
4A shows only the tip of the nozzle 22 of the liquid spray unit 20 and the one end 40a side of the object 40, and FIG. 4B shows the end 40a side of the object 40 to be coated. Only shows.

When the member 30 having the same polarity as the article to be coated 40 is not arranged, as shown in FIG. 4B, the end 40a of the object to be coated 40 is an electric field concentration portion where the electric field is concentrated.
And as shown to Fig.4 (a), the liquid sprayed from the nozzle 22 is in the state currently sprayed by offsetting a little above the nozzle 22, and it is strongly on the to-be-coated object 40 side. There is no appearance to be attracted.

  Such a phenomenon is thought to be caused by a change in the charged state of the sprayed liquid, and it is assumed that several factors are combined, but the main factors are as follows. it is conceivable that.

FIG. 5 is a schematic diagram for explaining the cause of the state of FIG. 4 (a), and is a schematic diagram of the liquid sprayed as seen from above.
As described above, since the liquid leaves the nozzle 22 in a charged state and atomization progresses due to electrostatic explosion, the atomized liquid is also in a charged state.
Then, as shown by the solid line arrow L in FIG. 5, the liquid in the charged state is attracted by the electrostatic force to the workpiece 40 in a different polarity state.

  For this reason, about the liquid which goes to the to-be-coated object 40 from the nozzle 22 in a straight line state, it is applied to the front side of the to-be-coated object 40 (the side facing the liquid spraying part 20), but in the lateral direction of the to-be-coated object 40. Even the liquid sprayed with an offset is attracted to the object 40 by electrostatic force and is applied to the side surface or the rear surface side of the object 40.

  On the other hand, when a voltage is applied between the object to be coated 40 and the liquid spraying part 20, the air existing between the object to be coated 40 and the liquid spraying part 20 is also ionized, so that it is charged.

  For this reason, this ionized air is also drawn toward the object 40 (see the dotted arrow A in FIG. 5), as in the case of the charged liquid fine particles described above. However, in the case of air, the ionized air is applied to the object 40. Since the air cannot be integrated, the air drawn toward the object to be coated 40 has no place to go.

  Therefore, the air attracted toward the object to be coated 40 is pressed against the surface of the object to be coated 40 with new ionized air or liquid that urges around the object to be coated 40, so that the object to be coated is obtained. It moves to the end 40a side of the article 40 to flow on the surface of 40.

  Further, as shown in FIG. 4B, the end 40a of the object to be coated 40 is an electric field concentration portion, so that the charged liquid and the ionized air are likely to gather together. Even if it sees, it will be in the condition where it is easy to make a flow to the edge part 40a side.

Therefore, air flows along the surface of the object to be coated 40 toward the end 40a, and the direction from the end 40a along the length direction of the object 40 to be coated (on the top of FIG. 4A). Direction).
However, the discharged air is neutralized (grounded) while flowing along the surface of the object to be coated 40, and approaches the same potential state as the potential of the object to be coated 40, or is in the same potential state. Become.

  When air in such a potential state is released from the end portion 40a of the object to be coated 40 into the liquid spray range, an action of discharging the charged liquid occurs, and the discharged liquid is covered by electrostatic force. It will float without being attracted to the coating 40.

For this reason, as shown in FIG. 4A, it is considered that a liquid that is not strongly attracted to the article 40 is generated.
The reason why the liquid spray is generated slightly upward from the nozzle 22 is presumed to be that the discharged air drifts upward and acts as a different pole part.

Therefore, in order to suppress such a phenomenon, in this embodiment, as shown in FIG. 1, a conductive material or a semiconductive material disposed in the vicinity of the electric field concentration portion (end portion 40 a) of the workpiece 40 is used. A member 30 is provided, and a voltage is applied between the member 30 and the liquid spray unit 20 so that the member 30 has the same polarity as the article 40 to be coated.
In this embodiment, as the member 30, an electrode member made of a conductive material or a semiconductive material having a surface resistance of 10 ¹⁰ Ω or less is used.

Specifically, as shown in FIG. 1, it is connected in the middle of the first electric wiring 42 from the first voltage application means 50 to the article 40 side, and is applied to the article 40 by the first voltage application means 50. The second voltage applying means is configured by providing the second electric wiring 42a that allows the applied voltage to be applied to the member 30. The member 30 is coated by the second voltage applying means. The same polarity as that of the object 40 has the same potential.
However, the second voltage application unit may be configured as another power supply voltage independent of the first voltage application unit 50.

(When member 30 is arranged)
Below, the spray state of the liquid at the time of arrange | positioning the member 30 made into the same polarity as such to-be-coated article 40 is demonstrated.
FIG. 6 is a diagram for explaining a liquid spray state and the like when the liquid is sprayed in a state where the member 30 having the same polarity as the article 40 described with reference to FIG. 1 is arranged. 6A is a diagram showing a state where the liquid is sprayed, and FIG. 6B is a diagram showing the state of the electric field of the article 40 and the member 30 with equipotential lines.

  6A shows only the tip of the nozzle 22 of the liquid spraying unit 20 and one end 40a side of the article 40 to be coated, and FIG. 6B shows the end 40a of the article 40 to be coated. Only the end 30a side of the member 30 is shown.

  Although not shown, as shown in FIG. 6, in order to arrange the member 30, in the electrostatic spraying device 10 of the present embodiment, the electric field concentration portion of the article 40 (FIG. 4B). It is assumed that a disposing means (holder) for disposing the member 30 is provided such that a part of the member 30 (specifically, the end portion 30a) is located within a predetermined range of the distance from the end portion 40a).

  As shown in FIG. 6B, the electric field concentration portion of the object to be coated 40 is formed so that the end portion 30a of the member 30 is opposed to the end portion 40a that has been the electric field concentration portion of the object to be coated 40. When the member 30 is disposed in the vicinity of the end 40a, the electric field is formed as if the object 40 and the member 30 are connected to each other as a single rod-shaped body. The electric field concentration at the end 40a is greatly reduced.

  The arrangement means (holder) for arranging the member 30 is an electric field concentration portion (the end of FIG. 4B) of the article 40 so that the article 40 and the member 30 are integrated. It is preferable that the member 30 can be arranged so that a part of the member 30 is located within a range within 20 mm from the distance from the portion 40a), and the member 30 can be arranged within 15 mm. More preferably, the member 30 can be disposed within 10 mm.

For this reason, as a whole flow as described above, it is possible to suppress a phenomenon in which a charged liquid or ionized air flows on the end portion 40a side of the workpiece 40.
In the state shown in FIG. 6, it is considered that air flows along the surface of the object to be coated 40, but as can be seen from FIG. 6A, the periphery of the end 40 a of the object to be coated 40. Is in a state in which new ionized air or charged liquid surrounds the periphery, so that the air flowing along the surface of the object to be coated 40 is not released and the end of the object to be coated 40 is It tends to flow toward the outside of the spray range of the liquid opposite to 40a.

  Further, even if there is air that has flowed to the end 40a side of the article 40, the air continues to flow along the surface of the member 30 and is guided outside the liquid spraying range. Not released within the spray range.

  For this reason, it is suppressed that the charged liquid is neutralized by the neutralized air, and a decrease in coating efficiency can be suppressed.

  In addition, the member 30 which is an electrode member configured as a rod-like member has a length from one end (the end 30a) to the other end on the opposite side so that the discharged air can be guided to the outside of the liquid spraying range. However, when one end (end portion 30a) is disposed in the vicinity of the electric field concentration portion of the article to be coated 40, it is preferable that the other end has a length that is located outside the spray range of the liquid.

  However, even if the length of the member 30 is not the length at which the other end of the member 30 is located outside the liquid spraying range, the length of the member 30 is not limited as long as it is close to the outside of the liquid spraying range. Since it is considered that the coating efficiency is greatly improved as compared with the case where the member 30 is not disposed, the length of the other end of the member 30 is not necessarily limited to a length outside the liquid spraying range.

  In this way, by suppressing the decrease in coating efficiency by spraying the liquid onto the object to be coated 40 in the state where the member 30 having the same polarity as the object to be coated 40 is disposed in the vicinity of the electric field concentration portion of the object to be coated 40. Is possible.

  On the other hand, in the above, an electrode member is used for the member 30, but if the same first coated object as the coated object 40 is used as the member 30, the liquid is simultaneously applied to the two coated objects 40. Since the application | coating operation | work can be performed, it may replace with using the member 30 which is an electrode member different from the to-be-coated object 40, and you may make it make the member 30 the 1st to-be-coated object same as the to-be-coated object 40.

  For this reason, the electrode member different from the object to be coated 40 is not an essential requirement, and at least has a second voltage applying means that makes the first object to be used as the member 30 the same polarity as the object to be coated 40. That's fine.

  In the case of a mode in which a dedicated electrode member is used for the member 30, as in the case of using the object to be coated 40, an arrangement means (holder) for arranging the member 30 every time the type of the object to be coated 40 changes. There is an advantage that there is no need to change the design.

  As mentioned above, although the electrostatic spraying apparatus 10 of this invention was demonstrated based on specific embodiment, this invention is not limited to said specific embodiment.

  In the above embodiment, the case where one member 30 is used for the object to be coated 40 has been described. However, as described above, the member 30 may be the same first object to be coated as the object to be coated 40. Therefore, when the same first coated object (coated object 40) as the coated object 40 is used as the member 30, a plurality of first coated objects (coated objects 40) are used as shown in FIG. Thus, the liquid may be applied to a large number of the objects to be coated 40 at a time to increase the efficiency of the work.

  Moreover, in the said embodiment, although the edge part 30a of the member 30 is made into the tapered shape, as shown in FIG. 8, even if the edge part 30a of the member 30 is not tapered, the state of the same electric field is produced. In addition, since the air guiding function can be exhibited, the end portion 30a of the member 30 is not limited to be tapered.

  Furthermore, in the said embodiment, although the 2nd electrical wiring 42a is directly connected to the member 30, the 2nd electrical wiring 42a is connected to the arrangement | positioning means (holder) which arrange | positions the member 30, and the arrangement | positioning means The second electric wiring 42a may be electrically connected to the member 30 through the connector.

  In addition, when the object to be coated 40 has an outer shape that fits within the spray range of the liquid, the above-described problem of reduction in the coating efficiency is likely to occur, and when the object to be coated 40 is a rod-shaped body. In the electrostatic spraying method using the electrostatic spraying device 10 and the electrostatic spraying device 10 of the present invention, the coating object 40 has an outer shape that fits within the liquid spraying range. This is particularly effective in the case of a rod-shaped body.

  However, when the object 40 is viewed as a whole, it does not necessarily have a shape that fits within the spray range of the liquid and is a rod-like body. Since the same problem is considered to occur even when the substrate 40 has an object, the object to be coated 40 to which the present invention is applied is not necessarily limited to a rod-like body, and a projection or the like that generates an electric field concentration portion. Are also included in the article 40 to be applied.

  As described above, the present invention is not limited to the above-described embodiment, and modifications and improvements as appropriate are also included in the technical scope of the present invention. It is clear from the description of the scope of claims.

DESCRIPTION OF SYMBOLS 10 Electrostatic spraying device 20 Liquid spray part 21 Body part 21a Liquid supply port 21b Liquid flow path 21c Hole part 21d Rear end opening part 21e Female screw structure 22 Nozzle 22a Tip outer periphery 22b Opening part 23 Mandrel 23a Knob part 23b Electrical wiring connection Portion 23c Male thread structure 23d End face 24 Seal member 30 Member 30a End 40 Object 40a End 41 Electrical wiring 42 First electrical wiring 42a Second electrical wiring 50 First voltage applying means 60 Grounding means 80 Tailor cone

Claims (12)

An electrostatic spraying device that sprays the liquid onto the object to be coated by separating the liquid from the nozzle of the liquid spraying part in a charged state by electrostatic force generated by application of voltage,
The liquid spraying section having the nozzle;
First voltage applying means for applying the voltage between the liquid spray portion and the object to be coated;
Secondly, the voltage is applied between a member made of a conductive material or a semiconductive material disposed in the vicinity of the electric field concentration portion of the liquid spray portion and the object to be coated, so that the member has the same polarity as the object to be coated. An electrostatic spraying device comprising: a voltage applying unit. The second voltage applying means is connected in the middle of the first electric wiring from the first voltage applying means to the object to be coated, and applies the voltage applied to the object by the first voltage applying means. A second electrical wiring that allows application to the member;
The electrostatic spraying device according to claim 1, wherein the second voltage applying unit sets the member to the same potential as the object to be coated. The member is a rod-shaped electrode member having one end disposed in the vicinity of the electric field concentration portion,
The length from the one end of the rod-shaped body to the other end on the opposite side is such that when the one end is disposed in the vicinity of the electric field concentration portion, the other end is located outside the spray range of the liquid. The electrostatic spraying device according to claim 1, wherein the electrostatic spraying device is provided.   2. The apparatus according to claim 1, further comprising an arrangement unit that arranges the member so that a part of the member is located within a range of a distance of 20 mm or less from the electric field concentration portion of the object to be coated. Item 4. The electrostatic spraying device according to any one of items 3 to 4. An electrostatic spraying method of spraying the liquid onto the object to be coated by detaching the liquid from the nozzle of the liquid spraying part in a charged state by electrostatic force generated by application of voltage,
Electrostatic spraying characterized in that the liquid is sprayed onto the object to be coated in a state where a conductive material or a semiconductive material having the same polarity as the object to be coated is disposed in the vicinity of the electric field concentration portion of the object to be coated. Method.   6. The electrostatic spraying method according to claim 5, wherein the potential of the member is the same as the potential of the article to be coated.   The electrostatic spraying method according to claim 5 or 6, wherein the first coated object same as the coated object is used as the member.   The electrostatic spraying method according to claim 7, wherein a plurality of the first objects to be coated are used as the member.   9. The electrostatic spraying method according to claim 7, wherein the electric field concentration portion of the first object to be coated is disposed in the vicinity of the electric field concentration portion of the object to be coated. The electric field concentration portion of the object to be coated and the first object to be coated is an end part,
The first object to be coated is arranged in the vicinity of the object to be coated such that the end of the first object to be coated is opposed to the end of the object to be coated. 8. The electrostatic spraying method according to 7.   The electrostatic spraying method according to claim 5 or 6, wherein the member is an electrode member different from the object to be coated.   The electrostatic spraying method according to claim 5, wherein the object to be coated and the member are rod-shaped bodies.

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