JP2017037730A - Position detection sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress decline in position detection accuracy, even when a position detection object is placed under high temperature, in a position detection sensor using a magnetic switch.SOLUTION: A position detection sensor 70 includes a case 71, a magnetic switch 72 placed in the case 71, a movable member 73 and a permanent magnet 80. The movable member 73 is attached with a magnetic material 74, in contact with an object directly or indirectly, and moves when the object is displaced. The permanent magnet 80 is placed in a space separated from the disposition space of the movable member 73, and moved toward the magnetic switch 72 as the magnetic material 74 is moved by movement of the movable member 73 caused by an attraction magnetic force generated between the magnetic material 74. When the permanent magnet 80 approaches a predetermined distance preset in the magnetic switch 72, the magnetic switch 72 detects the magnetism of the permanent magnet 80, and the position detection sensor 70 detects the position of the object.SELECTED DRAWING: Figure 3

Description

  The present application relates to a position detection sensor that has a magnetic switch and detects the position of an object.

  For example, as disclosed in Patent Document 1, a position detection sensor (position detection switch) that has a magnetic switch and detects the position of an object is known. In this patent document 1, the position detection sensor is provided in the liquid pumping device to detect the position of the float. In the liquid pumping device, the float rises and falls according to the liquid level, and when the float rises to a predetermined height, the stored liquid is discharged, and when the float lowers to a predetermined height, new liquid flows in and stores. Is done.

  The position detection sensor includes a magnetic switch, a movable member (movable shaft) containing a permanent magnet, and a contact member (coil spring) in contact with the float. In the position detection sensor, the contact member contacts the float and rotates as the float rises. As the contact member rotates, the movable member moves toward the magnetic switch. That is, as the float rises, the permanent magnet built in the movable member approaches the magnetic switch. When the float rises to a predetermined high level and the distance between the magnetic switch and the permanent magnet reaches a predetermined value, the magnetic switch detects the magnetism of the permanent magnet and turns on. Thus, it is detected that the float has reached the predetermined position. The contact member rotates in the opposite direction to the above as the float descends, and the movable member moves away from the magnetic switch as the contact member rotates. When the float falls below a predetermined high level, the distance between the magnetic switch and the permanent magnet becomes larger than a predetermined value, and the magnetic switch is turned off. That is, when the float is at a position lower than the predetermined high level, the magnetic switch is OFF.

JP2013-24061A

  For example, when the above-described liquid pumping device is one in which high-temperature drain generated by vapor condensation flows in and is stored, the permanent magnet is exposed to high temperature. That is, since the arrangement space of the movable member communicates with the storage space of the liquid pumping apparatus, high-temperature drain or steam flows into the arrangement space of the movable member, and the permanent magnet is exposed to a high temperature. Permanent magnets gradually decrease in magnetic force (magnetism) at high temperatures. When the magnetic force of the permanent magnet decreases in this way, the magnetic switch does not detect the magnetism of the permanent magnet even if the permanent magnet approaches the magnetic switch to a predetermined distance. Therefore, there is a problem that the accuracy of position detection is impaired.

  The technology disclosed in the present application has been made in view of such circumstances, and its purpose is to detect the position of a position detection sensor using a magnetic switch even when the position detection target is placed at a high temperature. The purpose is to suppress a decrease in accuracy.

  The position detection sensor of the present application includes a case, and a magnetic switch, a movable member, and a permanent magnet disposed in the case. The movable member is attached with a magnetic body and is in direct or indirect contact with the object, and moves in accordance with the displacement of the object. The permanent magnet is arranged in a space separated from the arrangement space of the movable member in the case, and the magnetic member is moved by the movement of the movable member by an attractive magnetic force generated between the permanent magnet and the magnetic member. Accordingly, it moves toward the magnetic switch. The position detection sensor of the present application detects the position of the object by detecting the magnetism of the permanent magnet when the permanent magnet approaches the magnetic switch to a predetermined distance set in advance. is there.

  As described above, according to the position detection sensor of the present application, the permanent magnet detected by the magnetic switch is arranged in a space isolated from the arrangement space of the movable member. Therefore, even when the object for position detection is arranged at a high temperature, it is possible to avoid a high-temperature fluid from flowing into the arrangement space of the permanent magnet. Therefore, the high temperature of the permanent magnet can be suppressed, and the magnetic force drop of the permanent magnet can be suppressed.

  In the position detection sensor of the present application, a magnetic body is attached to the movable member, and the permanent magnet is moved toward the magnetic switch along with the movement of the magnetic body by the attractive magnetic force generated between the magnetic body and the permanent magnet. I did it. Therefore, although the movable member and the permanent magnet are provided in separate spaces, the permanent magnet can be moved toward the magnetic switch as the movable member moves. Thereby, a permanent magnet can be brought close to a magnetic switch with the displacement of an object, and it can make a magnetic switch detect magnetism of a permanent magnet. As described above, according to the position detection sensor of the present application, it is possible to suppress a decrease in the magnetic force of the permanent magnet even when the position detection target is arranged at a high temperature, thereby suppressing a decrease in position detection accuracy. be able to.

FIG. 1 is a cross-sectional view illustrating a schematic configuration of a liquid pumping apparatus according to an embodiment. FIG. 2 is an enlarged cross-sectional view of the schematic configuration of the air supply valve and the exhaust valve. FIG. 3 is a cross-sectional view illustrating a schematic configuration of the position detection sensor according to the embodiment.

  Hereinafter, embodiments of the present application will be described with reference to the drawings. Note that the following embodiments are essentially preferable examples, and are not intended to limit the scope of the technology disclosed in the present application, applications thereof, or uses thereof.

  The liquid pumping apparatus 1 of this embodiment is provided in, for example, a steam system, and collects high-temperature drain (condensate) generated by steam condensation and pumps it to a boiler or a waste heat utilization apparatus. As shown in FIG. 1, the liquid pumping apparatus 1 includes a casing 10 that is a sealed container, an air supply valve 20 and an exhaust valve 30, a valve operating mechanism 40, and a position detection sensor 70 according to the claims of the present application. ing.

  In the casing 10, the main body 11 and the lid 12 are coupled by bolts, and a storage space 13 in which drain (liquid) flows is stored. A liquid inlet 14 through which drain flows, a liquid outlet 15 through which drain is discharged, a gas inlet 16 through which steam (working gas) is introduced, and steam (working gas) are discharged into the lid 12. Gas outlet 17 is provided. The liquid inflow port 14 is provided near the upper part of the lid part 12, and the liquid discharge port 15 is provided at the lower part of the lid part 12. Both the gas inlet 16 and the gas outlet 17 are provided in the upper part of the lid 12. These liquid inlets 14 and the like are all in communication with the storage space 13.

  As shown in FIG. 2, the gas inlet 16 is provided with an air supply valve 20, and the gas outlet 17 is provided with an exhaust valve 30. The air supply valve 20 and the exhaust valve 30 open and close the gas inlet 16 and the gas outlet 17, respectively. The air supply valve 20 discharges the drain of the storage space 13 from the liquid discharge port 15 by introducing steam into the storage space 13 from the gas introduction port 16. The exhaust valve 30 discharges the steam introduced into the storage space 13 from the gas discharge port 17.

  The air supply valve 20 includes a valve case 21, a valve body 22, and a lifting rod 23. The valve case 21 has a through hole in the axial direction, and a valve seat 24 is formed above the through hole. An opening 25 through which the through hole communicates with the outside is formed in the middle portion of the valve case 21. The valve body 22 is formed in a spherical shape, and is integrally provided at the upper end of the lifting rod 23. The elevating rod 23 is inserted into the through hole of the valve case 21 so as to be movable up and down. When the elevating rod 23 is raised, the air supply valve 20 is separated from the valve seat 24 and the gas inlet 16 is opened. When the elevating rod 23 is lowered, the valve body 22 is seated on the valve seat 24 and gas is supplied. The inlet 16 is closed.

  The exhaust valve 30 includes a valve case 31, a valve body 32, and a lifting rod 33. The valve case 31 has a through hole in the axial direction, and a valve seat 34 is formed slightly above the through hole. The valve case 31 is formed with an opening 35 through which the through hole communicates with the outside. The valve body 32 is formed in a substantially hemispherical shape, and is provided integrally with the upper end of the elevating rod 33. The elevating rod 33 is inserted into the through hole of the valve case 31 so as to be movable up and down. When the elevating rod 33 is raised, the exhaust valve 30 is seated on the valve seat 34 and the gas discharge port 17 is closed. When the elevating rod 33 is lowered, the valve body 32 is separated from the valve seat 34 and the gas is exhausted. The outlet 17 is opened.

  A valve operating rod 36 is connected to the lower end of the lifting rod 33 of the exhaust valve 30. That is, the raising / lowering rod 33 of the exhaust valve 30 moves up and down as the valve operation rod 36 moves up and down. The valve operating rod 36 is attached with a continuous plate 37 that extends to a region below the lifting rod 23 of the air supply valve 20. The raising / lowering rod 23 of the air supply valve 20 is pushed up by the connecting plate 37 when the valve operating rod 36 is raised, and rises. When the valve operating rod 36 is lowered, the connecting plate 37 is also lowered so that it is lowered by its own weight. That is, when the valve operating rod 36 is raised, the air supply valve 20 is opened (opens), while the exhaust valve 30 is closed (closed), and when the valve operating rod 36 is lowered, the air supply valve 20 is closed (closed). On the other hand, the exhaust valve 30 opens (opens).

  The valve operating mechanism 40 is provided in the casing 10 and moves the valve operating rod 36 up and down to open and close the air supply valve 20 and the exhaust valve 30. The valve operating mechanism 40 includes a float 41 and a snap mechanism 50.

  The float 41 is formed in a spherical shape, and a lever 42 is attached thereto. The lever 42 is rotatably supported by a shaft 43 provided on the bracket 44. The lever 42 is provided with a shaft 45 at the end opposite to the float 41 side. The snap mechanism 50 includes a float arm 51, a sub arm 52, a coil spring 53, and two receiving members 54 and 55. One end of the float arm 51 is rotatably supported by a shaft 58 provided on the bracket 59. The brackets 44 and 59 are coupled to each other by screws and attached to the lid portion 12. A groove 51a is formed at the other end of the float arm 51, and the shaft 45 of the lever 42 is fitted in the groove 51a. With this configuration, the float arm 51 swings about the shaft 58 as the float 41 moves up and down.

  The float arm 51 is provided with a shaft 56. The sub arm 52 has an upper end portion rotatably supported by a shaft 58 and a lower end portion provided with a shaft 57. The receiving member 54 is rotatably supported on the shaft 56 of the float arm 51, and the receiving member 55 is rotatably supported on the shaft 57 of the sub arm 52. A compressed coil spring 53 is attached between the receiving members 54 and 55. The sub arm 52 is provided with a shaft 61, and the lower end portion of the valve operating rod 36 is connected to the shaft 61.

<Configuration of position detection sensor>
The position detection sensor 70 is provided in the upper part of the main body 11 of the casing 10 and communicates with the storage space 13 to detect the position of the float 41 that is the object, and constitutes a magnetic sensor. As shown in FIG. 3, the position detection sensor 70 includes a case 71, a magnetic switch 72, a movable member 73, a magnetic body 74, a contact member 78, and a permanent magnet 80. In the present embodiment, the storage space 13 constitutes a space in which the float 41 that is the object is arranged.

  The case 71 is formed in a substantially columnar shape extending in the front-rear direction, the front side (one end side in the column axis direction) is located in the storage space 13 in the casing 10, and the rear side (the other end side in the column axis direction) is the casing 10. Located outside of. In the case 71, an insertion portion 71a of the movable member 73 and a housing portion 71e of the permanent magnet 80 are formed on the front side, and a housing portion 71b of the magnetic switch 72 is formed on the rear side. The insertion part 71a and the accommodating part 71e are positioned one above the other.

  The insertion portion 71 a is an insertion hole that extends rearward from the front end of the case 71, and is formed below the column axis of the case 71. The accommodating portion 71 e is a closed space extending in the front-rear direction, and is formed above the column axis of the case 71. The insertion portion 71a and the accommodating portions 71b and 71e are partitioned by a partition wall 71c. Thus, the insertion portion 71a, the accommodating portion 71b, and the accommodating portion 71e constitute an arrangement space for the movable member 73, the magnetic switch 72, and the permanent magnet 80, respectively, and are separated from each other. Further, the accommodating portion 71 e of the permanent magnet 80 is a space that is also isolated from the storage space 13.

  The magnetic switch 72 is fixed at a position facing the housing portion 71e of the permanent magnet 80 in the housing portion 71b. The movable member 73 is formed in a rod shape extending in the front-rear direction (the column axis direction of the case 71). The movable member 73 is inserted in the insertion part 71a of the case 71 so as to be movable (displaceable) in the front-rear direction. The movable member 73 has a magnetic body 74 built in and attached to the inner end side (rear end side). The magnetic body 74 is a ferromagnetic body made of, for example, iron, cobalt, nickel, or an alloy thereof.

  A bifurcated piece 71d is formed at the front end of the case 71, and a rotating plate 75 is provided on the bifurcated piece 71d. The rotating plate 75 is formed in a circular shape, and is rotatably attached to a central shaft 76 connected between the bifurcated pieces 71d. That is, the rotating plate 75 is rotatably supported by the case 71 via the central shaft 76. A bifurcated piece 73a is formed at the outer end (front end) of the movable member 73, and a connecting shaft 77 is connected between the bifurcated piece 73a. The connecting shaft 77 is provided through the outer edge of the rotating plate 75. That is, the rotating plate 75 is rotatably supported by the case 71 and the outer edge portion is connected to the movable member 73 via the connecting shaft 77.

  The contact member 78 is a member that is formed in an elongated rod shape and is displaced in contact with the float 41. In the present embodiment, the contact member 78 is a coil spring. One end of the contact member 78 is fixed to the rotating plate 75 by press fitting, and the other end (tip) extends above the float 41. The contact member 78 is configured such that the tip is in contact with the float 41 and rotates (displaces) together with the rotating plate 75 as the float 41 moves up and down. As the rotating plate 75 rotates, the movable member 73 moves in the front-rear direction. That is, the position detection sensor 70 is configured such that the movable member 73 indirectly contacts the float 41 and moves in the front-rear direction as the float 41 is displaced.

  The permanent magnet 80 is disposed so as to be movable (displaceable) in the front-rear direction in the accommodating portion 71e. The permanent magnet 80 is disposed in the accommodating portion 71e so as to attract the magnetic body 74 of the movable member 73 by magnetic force. That is, the magnetic force attracting each other between the permanent magnet 80 and the magnetic body 74 is generated. The permanent magnet 80 moves toward (or toward) the magnetic switch 72 or moves away from the magnetic switch 72 in accordance with the movement of the magnetic member 74 due to the movement of the movable member 73 by the above-described attractive magnetic force. Is configured to do. That is, in the position detection sensor 70, the permanent magnet 80 is moved in the same direction as the magnetic body 74 by the movement of the magnetic body 74. The position detection sensor 70 is configured such that when the permanent magnet 80 approaches the magnetic switch 72 to a predetermined distance set in advance, the magnetic switch 72 detects the magnetism of the permanent magnet 80 and detects the position of the float 41. ing.

<Operation of position detection sensor>
The valve operating mechanism 40 is displaced as the float 41 moves up and down, and moves the valve operating rod 36 up and down to open and close the air supply valve 20 and the exhaust valve 30. Specifically, in the liquid pumping apparatus 1, when the drain is not accumulated in the storage space 13, the float 41 is located at the bottom of the storage space 13 (state in FIG. 1). In this state, the valve operating rod 36 is lowered, the air supply valve 20 is closed, and the exhaust valve 30 is open. When drain is generated in the steam system, the drain flows from the liquid inlet 14 and accumulates in the storage space 13. As the drain accumulates in the storage space 13, the float 41 rises. In the storage space 13, the steam is discharged from the gas discharge port 17 as the drain accumulates.

  After the float 41 rises and contacts the tip of the contact member 78, in the position detection sensor 70, the contact member 78 rotates counterclockwise in FIG. As the rotating plate 75 rotates, the movable member 73 and the magnetic body 74 move backward. As the magnetic body 74 moves backward, the permanent magnet 80 also moves backward and approaches the magnetic switch 72. When the float 41 rises to the second predetermined high level, the permanent magnet 80 approaches the magnetic switch 72 to a predetermined distance, and the magnetic switch 72 detects the magnetism of the permanent magnet 80 and turns on. Thereby, it is detected that the float 41 has risen to the second predetermined high level. When the float 41 further rises and reaches the first predetermined high level (normally reverse high level), the valve operating rod 36 is raised by the snap mechanism 50. Thereby, the air supply valve 20 is opened and the exhaust valve 30 is closed.

  When the air supply valve 20 is opened, the steam (high-pressure steam) in the steam system flows from the gas inlet 16 and is introduced into the upper part of the storage space 13 (the upper space of the drain). Then, the drain accumulated in the storage space 13 is pushed downward by the pressure of the introduced steam and discharged from the liquid discharge port 15. That is, the drain of the storage space 13 is pumped. The drain pumped by the liquid pumping apparatus 1 is supplied to a boiler or a waste heat utilization apparatus. When the drain liquid level in the storage space 13 decreases due to the drainage, the float 41 descends. In the position detection sensor 70, as the float 41 descends, the contact member 78 and the rotating plate 75 rotate clockwise in FIG. 3 due to the weight of the contact member 78. As the rotating plate 75 rotates, the movable member 73 and the magnetic body 74 move forward. As the magnetic body 74 moves forward, the permanent magnet 80 similarly moves forward and moves away from the magnetic switch 72. When the float 41 descends below the second predetermined high level, the distance between the permanent magnet 80 and the magnetic switch 72 becomes longer than the predetermined distance, and the magnetic switch 72 is turned off. Thereby, it is detected that the float 41 has fallen below the second predetermined high level.

  Then, when the float 41 is lowered to a predetermined low level (normally reverse low level), the valve operating rod 36 is lowered by the snap mechanism 50, the air supply valve 20 is closed, and the exhaust valve 30 is opened. As a result, drain flows from the liquid inlet 14 and accumulates in the storage space 13, and the vapor of the storage space 13 is discharged from the gas outlet 17. The above cycle is repeated. Then, by measuring the number of times the position detection sensor 70 is turned ON / OFF, the operating state of the liquid pressure feeding device 1 is grasped. Further, while the above cycle is repeated, in the position detection sensor 70, the permanent magnet 80 and the magnetic body 74 are always attracted to each other by a magnetic force.

  As described above, according to the position detection sensor 70 of the above embodiment, the permanent magnet 80 detected by the magnetic switch 72 is arranged in the accommodating portion 71e isolated from the insertion portion 71a of the movable member 73. That is, in the position detection sensor 70 of the above-described embodiment, the insertion portion 71a and the storage space 13 communicate with each other, but the storage portion 71e of the permanent magnet 80, the storage space 13 and the insertion portion 71a are isolated from each other (not communicated). I did it. Therefore, it is possible to avoid high-temperature drain or steam in the storage space 13 from flowing into the accommodating portion 71e of the permanent magnet 80. Therefore, the high temperature of the permanent magnet 80 can be suppressed, and as a result, the magnetic force drop of the permanent magnet 80 can be suppressed.

  In the position detection sensor 70 of the above-described embodiment, the magnetic member 74 is attached to the movable member 73, and the permanent magnet 80 is moved by the magnetic force generated between the magnetic member 74 and the permanent magnet 80. Along with this, the magnetic switch 72 is moved. Therefore, even if the movable member 73 and the permanent magnet 80 are provided in separate spaces, the permanent magnet 80 can be moved toward the magnetic switch 72 as the movable member 73 moves. Thereby, the permanent magnet 80 can be brought close to the magnetic switch 72 in accordance with the displacement of the object (float 41), and the magnetism of the permanent magnet 80 can be detected by the magnetic switch 72. As described above, according to the position detection sensor 70 of the above-described embodiment, even when the position detection target is arranged at a high temperature, it is possible to suppress a decrease in the magnetic force of the permanent magnet 80. The decrease can be suppressed.

  In the position detection sensor 70 of the above embodiment, the accommodating portion 71e of the permanent magnet 80 is a closed space. However, the high temperature drain or steam of the storage space 13 flows into the accommodating portion 71e (arrangement space) of the permanent magnet 80. As long as it can be prevented, it may be a partially open space.

  In the position detection sensor 70 of the above-described embodiment, the movable member 73 is in contact with the object (float 41) indirectly. However, in the position detection sensor of the present application, the movable member is in direct contact with the object. It is good also as a structure which moves with a displacement.

  Moreover, although the said embodiment demonstrated the form which used the position detection sensor 70 for the liquid pumping apparatus 1, the position detection sensor of this application may be used for not only this but another apparatus and instrument. For example, the position detection sensor of the present application may be used for a drain tank in which the float rises and falls according to the drain water level.

  The technology disclosed in the present application is useful for a position detection sensor that has a magnetic switch and detects the position of an object.

70 Position detection sensor 71 Case 71a Insertion part (arrangement space of movable member)
71b Housing (magnetic switch placement space)
71e Housing (permanent magnet placement space)
72 Magnetic switch 73 Movable member 74 Magnetic body 80 Permanent magnet

Claims (1)

Case and
A magnetic switch disposed in the case;
A movable member that is disposed in the case, has a magnetic body attached thereto, and is in direct or indirect contact with the object, and moves in accordance with the displacement of the object;
The magnetic member is arranged in a space separated from the arrangement space of the movable member in the case, and the magnetic force generated by the movement of the movable member by the attractive magnetic force generated between the magnetic member and the magnetic member. A permanent magnet that moves toward the switch,
A position detection sensor, wherein when the permanent magnet approaches the magnetic switch to a predetermined distance set in advance, the magnetic switch detects the magnetism of the permanent magnet to detect the position of the object.

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