JP2012035170A - Electric leakage preventing part - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent electric leakage due to dew condensation.SOLUTION: An electric leakage preventing part 1 is installed in an electrostatic sprayer configured to eject a liquid to be sprayed from a nozzle 2 in the form of droplets D and to induction charge the droplets D by an electrode 3 to which a voltage relatively high compared to that of the liquid is applied, and is installed between a seal for waterproofing 12 as a high electric potential side part electrically connected to the electrode 3 and the nozzle 2 as an electric leakage protection side part protecting against electric leakage through a surface connected to the seal for waterproofing 12. The electric leakage preventing part 1 includes a groove-shaped ring recess portion 35 extended so as to divide a surface connecting the seal for waterproofing 12 and the nozzle 2, a lid-shaped portion 36 facing an opening of the ring recess portion 35 to narrow the opening, and a heater 34 provided on the inner surface in the ring recess portion 35 to heat the internal space of the ring recess portion 35.

Description

  The present invention relates to a leakage prevention unit provided in an induction charging type electrostatic spraying device that sprays a liquid such as a chemical solution using static electricity.

  Examples of the leakage preventing unit in the conventional electrostatic spraying device include the leakage preventing units 128 and 129 described in Patent Document 1 (see FIG. 7). Since the functions of these leakage prevention units 128 and 129 are the same, only the operation of leakage prevention unit 128 will be described in detail below. The leakage preventing portion 128 includes an annular portion 131 projecting from the inner surface of the bottom wall portion of the electrode holder 104 so as to surround the spray nozzle portion 102, and the opening portion facing the opening portion of the annular portion 131. It is provided with a collar 132 provided so as to narrow the opening. The flange portion 132 is formed in a flange shape that protrudes in the radial direction over the entire outer periphery of the spray nozzle portion 102.

  Thus, in the annular part 131, the annular recessed part 133 covering the whole outer periphery of the spray nozzle part 102 is formed. Since it is difficult for the droplet D to enter the inside of the annular recess 133, the continuous film due to the adhesion of the droplet D to the annular electrode 103, the electrode holder 104, etc. can be interrupted by the annular recess 133. By such an action, according to the leakage prevention units 128 and 129, the high potential of the annular electrode 103 is transmitted to the jet tube 111 side through the spray nozzle unit 102 and the high voltage cable 112 through the conductive droplet D. Is to prevent.

JP 2007-136289 A (paragraphs 0022 to 0024, FIGS. 1 to 3)

  However, when a spraying operation is performed in a room such as a greenhouse, a leakage may occur in the leakage prevention units 128 and 129 even though the leakage prevention units 128 and 129 are provided. Then, the inventors of this application investigated this cause, and as a result, found out that the dew condensation which arose on the inner surface of the annular recessed part 133 was a cause as follows.

  Various patterns are conceivable as the pattern in which dew condensation occurs on the inner surface of the annular recess 133. For example, when an electrostatic spraying device is brought into a hot and humid room from a low temperature outside the room, the air is hot and humid. Flows into the annular recess 133 and there is a pattern in which dew condensation occurs on the inner surface of the annular recess 133. In addition, when the spraying operation is started in the room, the humidity in the room increases with the passage of time, and condensation tends to occur more easily. When the condensation in the annular recess 133 grows, the condensation connects the continuous films on both sides of the leakage prevention unit 128 to cause leakage.

In order to solve the above problems, the leakage prevention unit of the present invention is
A liquid to be sprayed is ejected as a droplet from a nozzle, and is provided in an electrostatic spraying device configured to inductively charge the droplet by an electrode to which a relatively high voltage is applied to the liquid. ,
Provided between the electrode or a high potential side portion that is electrically connected to the electrode and a leakage protection side portion that is a portion intended to protect against leakage through a creeping surface connected to the high potential side portion. A leakage prevention unit,
A groove-like concave portion extending so as to divide the creeping surface connecting the high potential side portion and the leakage protection side portion;
A lid-like portion that narrows the opening opposite the opening of the recess;
A heater provided on the inner surface of the recess or the surface facing the opening of the lid-like portion and heating the internal space of the recess.

  The electrically connected portion is not particularly limited as long as it is a portion that is not electrically insulated. Examples of the electrically connected portion include a portion electrically connected with a conductive material or a semiconductive material.

  According to this configuration, by heating the internal space with the heater, the surface temperature of the surface forming the space (the inner surface of the annular recess or the surface facing the opening of the lid-shaped portion) is increased, It is possible to prevent dew condensation from occurring and to prevent leakage due to the dew condensation.

As the leakage prevention part,
The said heater illustrates the aspect comprised so that it might heat over the substantially full length of the said recessed part.

  According to this configuration, it is possible to prevent the occurrence of condensation over substantially the entire circumference of the annular recess, and it is possible to more reliably prevent the occurrence of electric leakage due to condensation.

The said heater illustrates the aspect comprised so that it might act | operate as follows.
(A) An aspect configured to operate when a high voltage is supplied to the electrode.
(B) An aspect configured to operate when the humidity around the electrostatic spraying device exceeds a predetermined value.
(C) A mode in which (a) and (b) are combined. That is, an aspect configured to operate when a high voltage is supplied to the electrode and the humidity around the electrostatic spraying device exceeds a predetermined value.

  According to these configurations, power consumption can be reduced.

Examples of the leakage prevention unit include the following modes.
(A) A mode in which the leakage protection side portion is the nozzle connected to the high potential side portion via an electrode holder that supports the electrode and / or a jet tube that supplies the liquid thereto.
(B) A mode in which the leakage protection side portion is on the counter electrode side in a high voltage cable that supplies a high voltage to the electrode.

  According to the leakage prevention unit according to the present invention, there is an excellent effect that leakage due to condensation can be prevented.

It is sectional drawing which shows the earth-leakage prevention part in the electrostatic spraying apparatus which concerns on 1st embodiment which actualized this invention. It is a perspective view of the leakage prevention part. It is a figure which shows the heater of the electrical leakage prevention part, (a) is a top view of the unfolded state, (b) is a side view of the state. It is sectional drawing which shows the example of a change of the leak prevention part. It is sectional drawing which shows the earth-leakage prevention part in the electrostatic spraying apparatus which concerns on 2nd embodiment which actualized this invention. It is sectional drawing which shows the earth-leakage prevention part in the electrostatic spraying apparatus which concerns on 3rd embodiment which actualized this invention. It is sectional drawing which shows the conventional electrical leakage prevention part.

  1 to 4 show a first embodiment embodying the present invention. The electrostatic spraying device of this example includes a nozzle 2 that ejects a liquid to be sprayed as droplets D, and a substantially annular electrode 3 that is disposed so that the inner periphery is close to the outer periphery of the diffusion range of the droplets D. And an electrode holder 4 that supports the electrode 3 with respect to the proximal end side of the nozzle 2, and a leakage prevention unit 1. In the following, when referring to the “front end side” or “base end side” with respect to the direction of the electrostatic spraying device including the leakage prevention portion, unless otherwise specified, the droplet outlet side of the nozzle 2 is the front end side, The opposite side is the base end side, and the direction based on these is meant.

  The nozzle 2 is configured to be connected to the jet tube 9 via the joint 16, and is configured to eject the liquid to be sprayed supplied through the jet tube 9 as droplets D. The nozzle 2 may be made of either a non-conductive material or a conductive material. The nozzle 2 of this example is made of resin in order to reduce the weight. On the side surface of the nozzle 2, a holder mounting portion 15 protruding in the radial direction is provided.

  A part of the jet tube 9 is made of a conductive material and is grounded, so that the liquid is grounded. The aspect of grounding the liquid is not limited to this, and other conductive portions (nozzle 2 described later, the liquid storage tank formed of a conductive material, etc.) in contact with the liquid or in the liquid An example of grounding an electrode or the like immersed in is illustrated.

  The electrode 3 is formed in an annular shape in this example, and is disposed so as to be close to the outside of the diffusion range of the droplet D ejected from the nozzle 2, via a high voltage cable 5 as a coated conductor. A high voltage (about +6.3 kV in this example) supplied from the power supply unit 8 is applied. The high voltage cable 5 is covered with a non-conductive material. The shape of the electrode 3 is not particularly limited as long as it is a substantially annular shape, and an aspect formed in a C shape with one portion broken or a plurality of members connected to each other by a conductor are arranged in a substantially annular shape. The aspect which consists of is illustrated.

  The electrode holder 4 is configured to seal and accommodate the electrode 3 in a waterproof manner, and an inner surface 12a that is in contact with the electrode 3 and a position where the droplet D can be attracted and adhered by the electric field of the electrode 3 during spraying. The waterproof seal 12 as a semiconductive member having the outer surface 12b is provided as a constituent element, and the constituent elements other than the waterproof seal 12 are made of a nonconductive member. The electric charge of the droplet D attached to the outer surface of the waterproof seal 12 is configured to escape to the electrode 3 through the waterproof seal 12. A holder support portion 31 protrudes from the proximal end side of the electrode holder 4, and the holder support portion 31 is attached to the nozzle 2 via the holder attachment portion 15.

  The holder support portion 31 includes a cylindrical support body 32 that extends substantially parallel to the central axis of the nozzle 2, and a bottomed cylinder that is formed on the outer periphery of the support body 32 coaxially with the support body 32 and that is open at the base end side. A cylindrical portion 33 and a cylindrical heater 34 mounted on the outer periphery of the support 32 in the cylindrical portion 33 are provided. Thus, in the cylindrical part 33, the groove-shaped annular recessed part 35 is provided over the perimeter of the outer periphery of the support body 32. As shown in FIG. The depth of the annular recess 35 extends in the length direction of the support body 32, and the opening portion faces the length direction of the support body. The base end side of the support body 32 is inserted into an attachment recess 15 a formed in the holder attachment portion 15 of the nozzle 2. The holder mounting portion 15 is provided with a lid-like portion 36 that confronts the opening of the annular recess 35 and narrows the opening.

  The leakage prevention unit 1 of the present invention is provided in the middle of a creeping surface connecting a high potential side portion and a leakage protection side portion which is a portion to be protected against leakage from the high potential side portion. In this example, the high potential side portion has a semiconductive surface having an inner surface 12a in contact with the electrode 3 and an outer surface 12b at a position where the droplet D can be attracted and adhered by the electric field of the electrode 3 during spraying. The waterproof seal 12 and the leakage protection side portion are the nozzles 2. The leakage prevention unit 1 of the present example includes a groove-shaped annular recess 35 extending so as to divide the creeping surface connecting the waterproof seal 12 and the nozzle 2, and the opening facing the opening of the annular recess 35. And a heater 34 that heats the internal space of the annular recess 35. At least the surface of these components is made of an electrically insulating material.

  The heater 34 is configured to heat and dry substantially the entire circumference of the annular recess 35. As shown in FIG. 3, the heater 34 of this example is a sheet heater provided with a heater layer 34a formed of metal (for example, aluminum) and protective layers 34b provided on both sides of the heater layer 34a. Has been. The heater layer 34a has a metal film pattern composed of repeated bent lines, and is formed by etching or thick film printing. The protective layer 34b is made of a heat-resistant film and has a laminate structure in which both surfaces of the heater layer 34a are adhesively coated. The thickness of the seat heater is not particularly limited, but it is exemplified that the thickness is about 0.2 to 1 mm.

Although the mounting method of the heater 34 is not particularly limited, the following method is exemplified.
(1) Direct mold As shown in FIG. 1, the mounting method is such that the surface of the heater 34 is directly exposed to a portion to be heated and heat is directly transferred. In the configuration shown in the figure, workability at the time of assembly is good if the heater 34 is wound around the support 32 of the holder support 31 before being attached to the holder attachment 15 and bonded and fixed.
(2) Indirect type As shown in FIG. 4, the heater 34 is sealed with a cover 38, and heat is transferred indirectly through the cover 38. Compared to the direct type, since the heater 34 is not directly exposed to the portion to be heated, the heat transfer effect is somewhat inferior, but there is an advantage that the waterproof effect is high. As shown in the figure, the heat transfer effect can be further improved by filling the gap between the heater 34 and the cover 38 with a heat conductive material 39 so that the gap has no air layer.

  A cable 41 for supplying power to the heater 34 is connected to the proximal end side of the heater 34 and is drawn to the jet tube side. In the embodiment shown in FIG. 1, the holder mounting portion 15 is provided with a through hole 15b, and is drawn out to the jet tube side through the through hole 15b. The gap between the cable 41 and the through hole 15b is waterproof and sealed with a sealant or a seal member (not shown). In addition, in the embodiment shown in FIG. 4, the lead-out portion of the cable 41 in the cover 38 is waterproof and sealed with a sealant or a seal member (not shown).

  As a control method of the heater 34, (a) a method of operating in conjunction with the supply of a high voltage to the electrode 3, (b) a humidity sensor for detecting the humidity around the electrostatic spraying device is provided and the humidity sensor is used. A method of operating when the detected humidity exceeds a predetermined value, and (c) a method combining these methods will be exemplified. According to these methods, the power consumption of the heater 34 can be reduced.

  According to the leakage prevention unit 1 of this example configured as described above, the inner space is heated by the heater 34 to thereby form the surface (the inner surface of the annular recess 35 or the lid-like portion 36). It is possible to increase the surface temperature of the surface facing the opening of the annular recess 35) to prevent condensation on the surface and to prevent leakage due to the condensation.

  Further, since the heater 34 is configured to heat substantially the entire circumference of the annular recess 35, it is possible to prevent the occurrence of condensation over substantially the entire circumference of the annular recess 35, and to prevent the occurrence of electric leakage due to condensation. It can prevent more reliably.

  Next, FIG. 5 shows a second embodiment that embodies the present invention. The earth leakage prevention units 19 and 20 are mainly different from the first embodiment in the following points. Accordingly, portions common to the embodiment are given the same reference numerals, and redundant description is omitted.

  The electrode holder 4 of this example is formed in a substantially cylindrical shape that covers the outer periphery of the nozzle 2 at the tip end side, and leakage preventing portions 19 and 20 are provided inside and outside the electrode holder 4.

  The leakage prevention portion 19 inside the electrode holder 4 is provided in the middle of the creeping surface between the outer surface 12 b of the waterproof seal 12 and the nozzle 2, and an annular portion 22 that protrudes so as to surround the nozzle 2. And a lid-like portion 21 provided so as to narrow the opening of the annular portion 22 so as to face the opening. And the groove-shaped annular recessed part 22a formed between the nozzle 2 and the annular part 22 interrupts | blocks the continuous film formed in the outer surface 12b of the waterproof seal 12, and between the outer surface 12b and the nozzle 2 is cut | disconnected. It is configured to prevent electric leakage.

  The leakage prevention portion 20 outside the electrode holder 4 is provided in the middle of the creeping from the nozzle 2 to the outer surface 12b of the waterproof seal 12, and is a quadruple circle projecting so as to surround the periphery of the nozzle 2. An annular portion 23 and double lid-like portions 24 and 26 are provided so as to confront the opening of the annular portion 23 and narrow the opening of the opening. And the groove-shaped annular recessed part 23a formed between the nozzle 2 and the annular part 23 interrupts | blocks the continuous film formed in the outer surface 12b of the waterproof seal 12, and between the nozzle 2 and this outer surface 12b. It is configured to prevent electric leakage.

  In the electrostatic spraying device configured as described above, the portion indicated by a two-dot chain line in the leakage preventing unit 19 and / or the leakage preventing unit 20 (the entire circumference in the annular recess 22a and / or the entire circumference in the annular recess 23a). Next, it is exemplified that the same heater 34 as that of the first embodiment is provided. As a mounting method of the heater 34, any of the direct type and the indirect type in the first embodiment can be adopted. The effect similar to 1st embodiment can be acquired also by the earth-leakage prevention part of this example.

  Next, FIG. 6 shows a third embodiment embodying the present invention. This leakage prevention unit 51 is mainly different from the first embodiment in the following points. Accordingly, portions common to the embodiment are given the same reference numerals, and redundant description is omitted.

  In the leakage prevention unit 51 of this example, the high potential side portion is an electrode or a portion electrically connected thereto, and the leakage protection side portion is in the high voltage cable 5 that supplies a high voltage to the high potential side portion. It is the counter electrode side. The leakage prevention portion 51 of this example is attached between the high potential side portion and the leakage protection side portion in the length direction of the high voltage cable 5, and the high voltage is transmitted along the surface of the high voltage cable 5. This is to prevent leakage of electricity to the site. This leakage prevention portion 51 is formed in a cylindrical support 52 configured to allow the high-voltage cable 5 to be inserted into the cylindrical hole, and is formed coaxially with the support 52 on the outer periphery of the support 52. An open bottomed cylindrical portion 53, a cylindrical heater 34 attached to the outer periphery of the support body 52 in the cylindrical portion 53, and an inner peripheral surface of the support body 52 at both ends of the support body 52. And the sealing members 55 and 55 for sealing the gaps between the high-voltage cable 5 and the outer peripheral surface of the high-voltage cable 5, respectively. .

  The end of the support 52 on the side of the leakage protection side portion is attached to a jet tube or the like via an attachment member 58. A groove-like annular recess 56 is formed on the outer periphery of the support 52 by the cylindrical portion 53, and a lid-like portion 57 that narrows the opening of the mounting member 58 against the opening of the annular recess 56. Are integrally formed. A cable 41 that supplies electric power to the heater 34 is connected to the leakage protection side portion side of the heater 34. In the embodiment shown in FIG. 6, the attachment member 58 is provided with a through hole 58a, and is drawn out to the leakage protection side portion side through the through hole 58a. The gap between the cable 41 and the through hole 58a is waterproof and sealed with a sealant or a seal member (not shown).

  In this example, the case where the direct type in the first embodiment is adopted as the mounting method of the heater 34 is illustrated, but the indirect type (see FIG. 4) in the same embodiment can also be adopted.

  The effect similar to 1st embodiment can be acquired also by the earth-leakage prevention part 51 of this example.

In addition, this invention is not limited to the said embodiment, For example, it can also be suitably changed and embodied as follows, for example in the range which does not deviate from the meaning of invention.
(1) Adopt a portion not illustrated in the above embodiment as the leakage protection side portion.
(2) The heater 34 is provided in a portion of the annular recesses 22a, 23a, and 35 that is not illustrated in the above embodiment, or is provided on a surface facing the opening in the lid-like portions 21, 24, 26, 36, and 57. thing.
(3) The present invention is used for an electrostatic spraying apparatus in which the electrode is a high potential side portion. As an electrostatic spraying device having such a configuration, in the first or second embodiment, the electrode 3 is not sealed and sealed in a waterproof manner by the electrode holder 4, and the electrode 3 is connected to the leakage protection side portion. The thing of the structure which has this is illustrated.

DESCRIPTION OF SYMBOLS 1 Leakage prevention part 2 Nozzle 3 Electrode 4 Electrode holder 5 High voltage cable 8 Power supply part 9 Jet pipe 12 Waterproof seal 12a Inner surface 12b Outer surface 15 Holder attachment part 15a Installation recessed part 15b Through-hole 16 Joint 19 Leakage prevention part 20 Leakage prevention part 21 Lid-shaped portion 22 annular portion 22a annular recess 23 annular portion 23a annular recess 24 lid-like portion 26 lid-like portion 31 holder support portion 32 support 33 tubular portion 34 heater 34a heater layer 34b protective layer 35 annular recess 36 lid-like Portion 38 Cover 39 Thermally conductive material 41 Cable 51 Leakage prevention portion 52 Support 53 Cylindrical portion 55 Sealing member 56 Annular recess 57 Lid-like portion 58 Mounting member D Droplet

Claims (6)

A liquid to be sprayed is ejected as a droplet from a nozzle, and is provided in an electrostatic spraying device configured to inductively charge the droplet by an electrode to which a relatively high voltage is applied to the liquid. ,
Provided between the electrode or a high potential side portion that is electrically connected to the electrode and a leakage protection side portion that is a portion intended to protect against leakage through a creeping surface connected to the high potential side portion. A leakage prevention unit,
A groove-like concave portion extending so as to divide the creeping surface connecting the high potential side portion and the leakage protection side portion;
A lid-like portion that narrows the opening opposite the opening of the recess;
An earth leakage prevention unit, comprising: a heater provided on an inner surface of the recess or a surface facing the opening of the lid-like portion and heating an internal space of the recess.   The leakage preventing part according to claim 1, wherein the heater is configured to heat over substantially the entire length of the recess.   The leakage preventing part according to claim 1 or 2, wherein the heater is configured to operate when a high voltage is supplied to the electrode.   The leakage preventing part according to claim 1 or 2, wherein the heater is configured to operate when a humidity around the electrostatic spraying device exceeds a predetermined value.   The leakage preventing side portion is the nozzle connected to the high potential side portion via an electrode holder that supports the electrode or / and a jet tube that supplies the liquid thereto. The leakage prevention part according to item.   The leakage prevention part according to any one of claims 1 to 4, wherein the leakage protection side portion is a counter electrode side in a high voltage cable that supplies a high voltage to the electrode.

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