JP2015049065A - Electrode holder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrode holder capable of stably maintaining a good sealability and improving durability even when installed in a container under a high temperature and a high pressure.SOLUTION: An electrode holder 1 comprises: a metallic cylindrical container fitting member 10 fixed to a container 2; an electrode shaft 20; and an insulation member 30 provided by insulating the cylindrical container fitting member 10 and the electrode shaft 20 in a gap therebetween. The insulation member 30 has: a water repellent cover part 35 exposed into the container 2 and coating the electrode shaft 20 for protection; and a load part 31 not exposed into the container 2 and including a portion on which a load received from the electrode shaft 20 by a pressure within the container concentrates. The water repellent cover part 35 is formed of a first insulation material which is resin with water repellency and sealability. The load part 31 is formed of a second insulation material with higher intensity than the first insulation material.

Description

  The present invention relates to an electrode holder for attaching an electrode for detecting a liquid level, electric conductivity, and the like of a liquid in a container to the container.

  Conventionally, the level of liquid in a boiler can or a water supply tank, electric conductivity, and the like have been detected. For example, based on the electrical continuity between the detection electrode and the metal container, the detection electrode is attached to the metal container communicating with the boiler body or water supply tank in an insulated state by an electrode holder. Thus, the liquid level and electrical conductivity are detected.

  Such an electrode holder is disclosed in, for example, Patent Documents 1 and 2 below, and includes a container mounting member attached to a metal container, an electrode shaft to which a detection electrode is fixed, a container mounting member, and an electrode shaft. And an insulating member interposed in the gap.

  Here, as the insulating member, ceramic has been used in consideration of insulation between the container mounting member and the electrode shaft, but in recent years, a fluororesin having excellent water repellency has been used. ing. However, ceramics are still used because there is a risk that the fluororesin may break due to insufficient strength under conditions where the temperature of the metal container is high and high pressure.

Japanese Patent No. 4419155 JP 2000-046629 A

  However, when the insulating member is made of ceramic, the ceramic is a hard material and lacks flexibility, so there is a limit to the sealing performance, and the gap between the insulating member and the container mounting portion or the electrode shaft is limited to the inside of the metal container. Vapor may leak. In addition, ceramic is inferior in water repellency, and therefore requires glaze application. However, glaze has difficulty in alkali resistance, and if the glaze is peeled off, insulation deterioration may occur. In addition, the ceramic may be broken.

  The present invention has been made in view of such problems, and maintains an electrode that can stably maintain a good sealing property and improve durability even when installed in a container under high temperature and high pressure. The purpose is to provide a vessel.

  In order to solve the above problems, an electrode holder according to the present invention is an electrode holder that holds an electrode that is fixed to a container and is immersed in the liquid in the container. A cylindrical container mounting member; a metal electrode shaft that is installed so as to extend into a hollow interior of the cylindrical container mounting member and to which the electrode is fixed; and the cylindrical container mounting member and the electrode shaft. An insulating member that is installed in a gap to insulate both, and the cylindrical container mounting member supports the electrode shaft through the insulating member, and the insulating member is exposed in the container, A water repellent cover portion for covering the electrode shaft, and a load portion including a portion where the load received from the electrode shaft by the pressure in the container is concentrated without being exposed in the container, The water-repellent cover portion is a tree having water repellency and sealing properties. Is formed from a first insulating material is, the load unit is characterized in that than the first insulating material is formed from a second dielectric material of a high strength.

  According to the electrode holder of the present invention, it is possible to stably maintain a good sealing property even when installed in a container under a high temperature and high pressure, and to improve durability.

FIG. 1 is a longitudinal sectional view of an electrode holder according to an embodiment of the present invention. FIG. 2 is an enlarged vertical cross-sectional view of a main part of the electrode holder according to the embodiment of the present invention. FIG. 3 is a horizontal sectional view taken along line AA of FIG.

  Hereinafter, an electrode holder according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a longitudinal sectional view of an electrode holder according to the present embodiment. FIG. 2 is an enlarged vertical cross-sectional view of a main part of the electrode holder according to the present embodiment. FIG. 3 is a horizontal sectional view taken along line AA of FIG. In the present embodiment, an electrode holder 1 that is installed in a metal container 2 that communicates with a boiler can and detects the liquid level, electrical conductivity, etc. of the liquid in the container 2 will be described as an example. To do.

  The electrode holder 1 includes a container mounting member 10 fixed to the container 2, an electrode shaft 20 that holds a detection electrode immersed in the liquid in the container 2, a container mounting member 10, and an electrode shaft 20 And an insulating member 30 that insulates the two from each other.

  The electrode shaft 20 is installed through the hollow interior of the container mounting member 10, and a gap between the electrode shaft 20 and the container mounting member 10 is filled with an insulating member 30. In such a configuration, the container mounting member 10 fixed to the container 2 holds the electrode shaft 20 via the insulating member 30.

  The container mounting member 10 is a stainless steel member and has a substantially cylindrical shape with a hollow inside. The container attachment member 10 has an exposed portion 11 located on the upper side in FIG. 1 and a fitting portion 15 located on the lower side.

  The exposed portion 11 is a portion exposed to the outside of the container 2 in a state where the container mounting member 10 is fitted and installed in the container 2, and includes a small diameter portion 12 positioned at the upper end and a main body portion 13. The inner diameter of the inner peripheral surface of the small diameter portion 12 is the smallest among the container mounting members 10, and the gap between the inner peripheral surface of the container mounting member 10 and the outer peripheral surface of the electrode shaft 20 is the small diameter portion 12. The narrowest. That is, the thickness of the insulating member 30 is the smallest at the small diameter portion 12. The small diameter portion 12 is caulked radially inward during manufacturing, as will be described later.

  Here, when the inside of the container 20 becomes high pressure, the force that the electrode shaft 20 receives due to the pressure is, via the insulating member 30, the lower end portion of the small-diameter portion 12 (the portion B surrounded by the broken circle in FIG. The container mounting member 10 receives the load received from the electrode shaft 20 substantially at the lower end portion of the small diameter portion 12. The fitting portion 15 is a portion that is fitted and fixed to the container 2, and a male screw portion 16 is formed on the outer peripheral surface of the fitting portion 15 to be screwed into the container 2 and fixedly installed. In addition, since the outer peripheral surface of the main-body part 13 of the exposed part 11 needs to fit a spanner at the time of attachment of the container attaching part 10, a horizontal cross section is a regular hexagon (refer FIG. 3).

  The electrode shaft 20 is a rod-shaped member made of stainless steel, and is installed to extend vertically through the hollow interior of the container mounting member 10. The electrode shaft 20 includes, in order from the top, a terminal portion 21, a first flange portion 23 that is a radially protruding portion that protrudes in a radial direction orthogonal to the axial direction, and a second flange portion 25 that is also a radially protruding portion. And an electrode mounting portion 28.

  The terminal portion 21 located at the upper end of the electrode shaft 20 is exposed to the outside of the container 2 in a state where the electrode holder 1 is installed in the container 2, and is a terminal connected to a power source. The first flange portion 23 is a portion protruding in a flange shape toward the outside in the radial direction of the electrode shaft 20, and protrudes over the entire circumference of the electrode shaft 20. Further, the first flange portion 23 has a shape in which the distal end protruding outward in the radial direction is bent 90 ° upward and protrudes upward in the axial direction (axial annular projecting portion 231).

  The 2nd flange part 25 is the part which protruded in the flange shape toward the radial direction outer side similarly to the 1st flange part 23, and protrudes over the perimeter around an axis | shaft. Further, the second flange portion 25 has a shape in which the tip protruding in the radial direction is bent 90 ° downward and protrudes downward in the axial direction (axial annular protruding portion 251).

  The electrode mounting portion 28 located at the lower end of the electrode shaft 20 is a portion to which an electrode immersed in the liquid in the container 2 is screwed and connected and fixed, and a female screw is formed. Further, the portion between the terminal portion 21 of the electrode shaft 20 and the first flange portion 23 and opposed to the small diameter portion 12 of the container mounting member 10 is dug in the radial direction over the entire circumferential direction. An annular groove 22 is formed, and an O-ring 221 is installed in the annular groove 22. This O-ring 221 enhances the sealing performance between the electrode shaft 20 and the insulating member 30.

  The insulating member 30 is installed so as to cover the electrode shaft 20 from the vicinity of the lower portion of the terminal portion 21 to the vicinity of the upper portion of the electrode mounting portion 28, and has a hollow tube shape as a whole. The insulating member 30 includes a load portion 31 that is located on the upper side in FIG. 1 and is not exposed in the container 2, and a water repellent cover portion 35 that is located on the lower side and is exposed in the container 2. In the present embodiment, different materials are adopted for the load portion 31 and the water repellent cover portion 35.

  The load portion 31 is located at the upper end portion of the insulating member 30, and the lower end thereof is located near the upper end of the first flange portion 23 of the electrode shaft 20. In the load portion 31, when the inside of the container 20 becomes high pressure, the force that the electrode shaft 20 tries to move upward due to the pressure is the lower inner portion of the load portion 31 that contacts the electrode shaft 20 at a horizontal boundary ( It concentrates on the part A) surrounded by the dashed circle in FIG.

  The load portion 31 including the portion A where the load applied to the electrode shaft 20 is concentrated is not exposed to the inside of the container 2 in a state where the electrode holder 1 is installed, and is not immersed in the liquid. Water repellency, chemical resistance, alkali resistance, etc. required when contacting the atmosphere in 2 are not required. Therefore, in the present embodiment, PEEK (polyether ether ketone), which is a high-strength resin material excellent in high pressure resistance, is used as the material constituting the load portion 31.

  Moreover, as shown in FIG. 2, the load part 31 is comprised by the size which can make a micro clearance gap between the container attachment member 10 which is a member made from stainless steel, and the electrode shaft 20 in a normal atmosphere. . In the vicinity of the small-diameter portion 12 of the load portion 31, an annular groove 315 is formed that is dug in the radial direction over the entire circumference, and an O-ring 316 is installed in the annular groove 315.

  As will be described later, the small diameter portion 12 of the container mounting member 10 is caulked inward in the radial direction. Therefore, even if a minute gap is provided between the load portion 31 and the container mounting member 10, the sealing performance at the boundary between the two can be secured by caulking the small diameter portion 12 and installing the O-ring 316. Further, with respect to a minute gap between the load portion 31 and the electrode shaft 20, sealing performance is secured by caulking of the small diameter portion 12 and the O-ring 221 installed at the boundary between the load portion 31 and the electrode shaft 20. be able to.

  As described above, when the small diameter portion 12 is caulked inward, a small gap is formed between the load portion 31 of the insulating member 30 and the stainless steel container mounting member 10 and the electrode shaft 20. When the load portion 31 is thermally expanded below, thermal expansion can be absorbed by the gaps, damage due to thermal expansion can be prevented, and durability of the electrode holder 1 can be improved. Moreover, by providing a gap, the load portion 31 can be easily assembled with the container mounting member 10 and the electrode shaft 20 during assembly described later. Note that this gap may be provided only between the load portion 31 and the container mounting portion 10 or between the load portion 31 and the electrode shaft 20.

  The water repellent cover portion 35 is the remaining portion of the insulating member 30 located below the load portion 31, and the electrode shaft 20 near the upper side of the electrode mounting portion 28 from the upper portion of the first flange portion 23 of the electrode shaft 20. Is covered.

  Thus, although the water repellent cover part 35 is a part exposed in the container 2, the load by the container attaching member 10 holding the electrode shaft 20 is not so much. Therefore, the water repellent cover portion 35 is not required to have a high strength, but is required to have water repellency, chemical resistance, alkali resistance, sealing property (flexibility), heat resistance, and the like. In the present embodiment, as a material constituting the water repellent cover portion 35, a fluororesin (PFA: tetrafluoroethylene / perfluoroalkyl) which is a resin material excellent in water repellency, chemical resistance, alkali resistance, sealability, and heat resistance. Vinyl ether copolymer) was used.

  Moreover, the load part 31 and the water-repellent cover part 35 are comprised so that the boundary of both in a longitudinal cross-section may become the shape which was mutually complicated. Specifically, as shown in the longitudinal sectional view of FIG. 2, an annular groove 311 is formed in the axial direction so that the lower end portion of the load portion 31 has an inverted U shape at the boundary portion, and the water repellent cover An annular groove 351 is formed in the axial direction so that the upper end of the portion 35 is U-shaped.

  Further, at the boundary portion between the load portion 31 and the water repellent cover portion 35, the load portion 31 is formed with an annular projecting portion 313 that projects downward in the axial direction, and the water repellent cover portion 35 has an axially upper portion. A projecting annular projecting portion 353 is formed. The annular protrusion 353 of the water repellent cover 35 is fitted into the annular groove 311 of the load 31, and the annular protrusion 313 of the load 31 is fitted into the annular groove 351 of the water repellent cover 35. Yes.

  In this way, the annular protrusions 353 and 313 in the opposite axial direction are fitted into the annular grooves 311 and 351, so that the boundary between the two is intricate, and the load portion 31 and the water repellent cover are formed. The sealing performance at the boundary with the portion 35 can be greatly improved.

  This is because the boundary between the load portion 31 and the water repellent cover portion 35 is made intricate, and as will be described later, when the electrode holder 1 is manufactured, the PFA that is the material of the water repellent cover portion 35 is formed. This is because the load portion 31 is tightened at the boundary portion.

  In addition, by adopting an intricate structure, even if the load 31 formed of high-strength PEEK thermally expands at high temperatures and stress is generated, a water-repellent cover formed of PFA having excellent flexibility The stress can be relaxed by the portion 35, and stress concentration or breakage due to thermal expansion of the load portion 31 can be prevented.

  An O-ring 312 is installed in the annular groove 311 described above. The O-ring 312 can further improve the sealing performance at the boundary between the load portion 31 and the water repellent cover portion 35.

  In addition, the annular grooves 311 and 351 and the annular protrusions 313 and 353 formed in the load part 31 and the water repellent cover part 35 at the boundary part are not limited to the configuration formed in the axial direction, but the annular protrusions As long as 313 and 353 are configured to fit into the opposite annular grooves 351 and 311, the annular groove and the annular protrusion may be formed in the radial direction, or may be oblique to the axial direction or the radial direction. These may be formed, or may be a combination of these.

  The material which comprises the load part 31 can be changed suitably, and the high intensity | strength insulating material excellent in load resistance can be used suitably. As the material of the load portion 31, for example, engineering plastics such as PAI (polyamideimide) and PPS (polyphenylene sulfide), ceramics, and the like can be used.

  The material constituting the water repellent cover portion 35 can be changed as appropriate, and an insulating material having high water repellency and high flexibility can be used as appropriate. As a material of the water repellent cover portion 35, for example, a fluorine-based insulating resin other than PFA, silicon, or the like can be used. In the present embodiment, the resin material constituting the water repellent cover portion 35 is referred to as a first insulating material, and the material constituting the load portion 31 is referred to as a second insulating material.

  While the configuration of the electrode holder 1 has been described in detail above, a method for manufacturing the electrode holder 1 will be described. First, the stainless steel container mounting member 10 and the electrode shaft 20 are manufactured. Further, the load portion 31 made of PEEK in the insulating member 30 is manufactured separately from the water repellent cover portion 35 by resin molding. Subsequently, as shown in FIG. 2, the electrode shaft 20 is formed by itself with the O-ring 221 attached to the annular groove 22 of the electrode shaft 20 and the O-ring 312 attached to the annular groove 311 of the load portion 31. Insert into the load 31. Thereby, the vicinity of the annular groove 22 of the electrode shaft 20 is covered by the load portion 31.

  Subsequently, with the O-ring 316 mounted in the annular groove 315 of the load portion 31, the electrode shaft 20 covered with the load portion 31 is inserted into the hollow interior of the container mounting member 10 and positioned at the location shown in FIG. . Thereby, first, the load part 31 of the container attachment member 10, the electrode shaft 20, and the insulating member 30 is assembled.

  Next, the gap between the container mounting member 10 and the electrode shaft 20 is filled, and PFA, which is a thermoplastic resin, is filled so as to cover the portion of the electrode shaft 20 that protrudes downward from the container mounting member 10. The water repellent cover portion 35 is formed by insert molding. Then, the electrode holder 1 is completed by caulking the small diameter portion 12 inward in the radial direction.

  Although the present embodiment has been described above, according to the present embodiment, the insulating member 30 interposed between the container mounting member 10 and the electrode shaft 20 includes the load portion 31 and the water repellent cover 35 made of different materials. The load portion 31 where the load received from the electrode shaft 20 at high pressure in the container 2 is concentrated uses a high-strength insulating material excellent in load resistance, and the water repellency exposed in the container 2 that can be a high-temperature and high-pressure environment. The cover part 35 is made of an insulating material having high water repellency and high flexibility, so that it maintains a stable and good sealing performance even when the electrode holder 1 is installed in a container 2 under high temperature and high pressure, and is durable. Can be improved.

  For example, when the inside of the container 2 in which the electrode holder 1 is installed is at a high temperature and high pressure, a force that causes the electrode shaft 20 to jump out due to a pressure difference from the atmospheric pressure outside the container 2 is concentrated on the load portion 31. However, since PEEK that forms the load portion 31 is a high-strength material, breakage due to a large load can be prevented.

  Further, even when the inside of the container 2 is in a high-temperature alkaline environment, the PFA that forms the water-repellent cover portion 35 exposed in the container 2 is water repellency, chemical resistance, alkali resistance, and sealing properties. Since the material has excellent heat resistance, the electrode shaft 20 can be reliably protected and deterioration can be prevented.

  The embodiment of the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the gist of the present invention. For example, the shape, size, material, and the like of each member constituting the electrode holder 1 can be changed as appropriate.

DESCRIPTION OF SYMBOLS 1 Electrode holder 10 Container attachment member 11 Exposed part 12 Small diameter part 13 Body part 15 Fitting part 16 Male thread part 20 Electrode shaft 21 Terminal part 22 Annular groove 221 O-ring 23 First flange part 231 Axial annular protrusion part 25 Two flange portions 251 Axial protruding portion 28 Electrode mounting portion 30 Insulating member 31 Load portion 311 Annular groove 312 O-ring 313 Annular protrusion 315 Annular groove 316 O-ring 35 Water repellent cover 351 Annular groove 353 Annular protrusion 2 Container

Claims (4)

In the electrode holder that holds the electrode fixed to the container and immersed in the liquid in the container,
A metal cylindrical container mounting member fixed to the container;
A metal electrode shaft that is installed so as to extend into the hollow interior of the cylindrical container mounting member and to which the electrode is fixed;
An insulating member that is installed in a gap between the cylindrical container mounting member and the electrode shaft;
The cylindrical container mounting member supports the electrode shaft via the insulating member,
The insulating member is exposed in the container and covered with a water-repellent cover portion for protecting the electrode shaft, and a load received from the electrode shaft by the pressure in the container is not exposed in the container. A load portion including a portion to be
The water repellent cover portion is formed of a first insulating material that is a resin having water repellency and sealing properties,
The load holder is formed of a second insulating material having a strength higher than that of the first insulating material. The load portion is configured such that a minute gap is formed on at least one of the boundaries between the cylindrical container mounting member and the electrode shaft,
The electrode holder according to claim 1, further comprising an O-ring for sealing the gap. The load portion is formed with an annular groove and an annular protrusion at a boundary portion with the water repellent cover portion,
The water repellent cover portion is formed with an annular groove and an annular protrusion at a boundary portion with the load portion,
The annular protrusion of the load portion is configured to fit into the annular groove of the water repellent cover portion, and the annular protrusion of the water repellent cover portion is configured to fit into the annular groove of the load portion. The electrode holder according to claim 1 or 2.   The electrode holder according to claim 3, further comprising an O-ring installed at a boundary portion between the load portion and the water repellent cover portion.

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