JPH0835876A - Level switch - Google Patents

Abstract

PURPOSE:To prevent the damage of a spring due to float rotation by directly regulating the rotation of the float itself with a vertical groove for a guide provided around the float and a guide coupled with the vertical groove for the guide. CONSTITUTION:On the surface of a stopper facing to the float 45, a cylindrical guide wall 54 is provided. At a part of the tip end of the guide wall 54, a guiding mail part 55 engageable with a vertical groove 52 for the guide formed in the float 45 is formed so as to extend in a radial direction. With a level switch 50 formed in this manner, gas is relieved from an accumulator at a periodic inspection. Even if rotational force is caused in the float 45 at the moment, the rotation of the float 45 is prevented by the vertical groove 52 provided as the guide formed in the float 45 and the nail part 55 of the guide wall 54 provided on the stopper 46, and therefore, the damage of the spring 47 is prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a level switch used in an accumulator device of a control rod drive water pressure device of a boiling water reactor.

[0002]

2. Description of the Related Art The output control of a boiling water reactor is performed by inserting and pulling out control rods in addition to the flow rate control by a coolant. Also, in an emergency, insert the control rod in an emergency.
Shut down the reactor.

The control rod drive mechanism inserts and pulls out the control rod. A plurality of control rod drive mechanisms are installed in the reactor in correspondence with the number of control rods to be inserted into and extracted from the reactor core, and the control rod drive mechanism operates by supplying drive water from each control rod drive water pressure device. Further, in the event of an emergency, the control rod drive mechanism urgently inserts the control rod into the core portion by supplying the high-pressure water stored in the accumulator device of the control rod drive water pressure device.

FIG. 5 shows a concrete example of the configuration of the control rod drive water pressure device described above. This control rod drive water pressure device 1 comprises an accumulator device 2 and a switching device 3.
The accumulator device 2 is connected to the insertion pipe 6 via a valve 4 and a scrum valve 5, and a control rod drive mechanism (not shown) is connected to the tip of the insertion pipe 6.
A filling water pipe 8 is connected to the pipe 7 between the scrum valve 5 and the accumulator device 2.

The accumulator device 2 includes an accumulator 10, a gas container 11, and a pipe 1 for connecting them.
2 and an instrumentation unit 13 inserted in the pipe 12.

The accumulator 10 has an end plate 2 at the upper and lower ends.
It is composed of a cylinder 23 closed by 1, 22 and a piston 24 inserted in the cylinder 23 so as to be vertically movable. A gas chamber 26 formed between the end plate 22 and the piston 24 has a gas chamber 26. The pipe 12 is connected.

The instrumentation unit 13 includes a level switch 31 and a valve 3 provided between the pipe 12 and the gas inlet 30.
2 and a pressure switch 33 connected between the gas inlet 30 and the valve 32.

As shown in FIG. 6, the level switch 31 has a switch main body 40 composed of a main body upper portion 41 and a lower main body portion 42, a base end connected to the main body upper portion 41, and a tip end being a convex portion of the main body lower portion 42. Recess 43 formed inside 43a
a guide pipe 44 inserted in b, a float 45 fitted to the convex portion 43a of the lower body 42 so as to be vertically movable,
A stopper 46 attached to the tip of the convex portion 43a of the lower body 42 for preventing the float 45 from falling off the convex portion 43a, the stopper 46 and the float 4
5, a spring 47 that is interposed between the float 45 and the float 45 and generates a spring force in a direction in which the float 45 and the float 46 are separated from each other;
It is roughly composed of.

The spring 47 assists in raising the float 45 when water reaches the float 45,
The level switch 31 is provided for quick detection of water. Therefore, the spring 47 when the water surface does not reach the float 45 is
It is held in a contracted state by its own weight.

The float 45 is made of a material or structure having a specific gravity smaller than that of water, and a magnet 48 is embedded inside. Further, protrusions 45a and 45b are provided on the upper portion of the float 45, which prevents the float 45 itself from being in contact with the lower flat surface 43c of the lower portion 42 of the main body.

A reed switch 49 is built in the guide pipe 44. As a result, when the magnet 48 embedded in the float 45 approaches the reed switch 49, the reed contact of the reed switch 49 is closed by the magnetic force of the magnet 48 itself, and as a result,
The position of the float 45 is detected.

In the above apparatus, the water chamber 25 of the accumulator 10 stores water necessary for driving the control rod drive mechanism in an emergency, and the gas container 11 stores the water in the accumulator 10. A gas having the pressure necessary to supply the control rod drive mechanism is stored.
The pressure inside the gas container 11 is set lower than the water pressure from the filling water pipe 8.

The scrum valve 5 is normally closed, so that the piston 24 in the accumulator 10 is closed.
Is constantly pressed against the lower end plate 22 by the water pressure from the filling water pipe 8 to compress the gas in the gas container 11 and to supply the accumulator 10 with a necessary amount of water in an emergency.
Is stored in.

Further, the piston 2 in the accumulator 10
Water leakage from 4 is monitored by a level switch 24, while gas container 11, piston 24, cylinder 21
Gas leakage from the welded portion between the end plate 22 and the end plate 22 or the seal portion of the instrumentation unit 13 is constantly monitored by the pressure switch 33 to secure water and gas at a pressure necessary in an emergency.

[0015]

In the control rod drive water pressure device constructed as described above, when inspecting the accumulator device 2 during the periodic inspection, the plug (not shown) of the gas inlet 30 is removed and the valve is opened. Although the gas is discharged by opening the valve 32, the level switch 31 is on the flow path of the exhaust gas. Therefore, when the exhaust gas has a strong momentum, a gas flow in the cross-sectional direction is generated around the float 45. When the lateral component of the gas flow is unbalanced, a rotational force is generated in the float 45, which may damage the spring 47.

Japanese Patent Application Laid-Open No. 1-207695 exists as a prior application for solving the above problems. This is to prevent the float 45 from rotating,
5 or the circumference of the spring 47 is covered with a windshield, or the float 45 itself has a finned or streamlined outer shape.

However, neither of the two methods described in the above-mentioned prior application directly controls the rotation of the float 45 itself, so that a rotational force may still be generated in the float 45 and the spring 47 may be damaged.

[0018]

In order to solve the above-mentioned problems, according to claim 1 of the present invention, a reed switch installed in the main body and the main body penetrates the main body to penetrate the reed switch. A float that moves up and down along with it, a magnet attached to the float to actuate the reed switch, a stopper connected to one side of the body to prevent the float from falling off, the float and the In a level switch including a spring interposed between a stopper and a guide, a vertical groove for guiding is provided on a peripheral surface of the float, and a guide for engaging the vertical groove for guiding on the stopper or the main body. Is provided.

According to the second aspect of the present invention, the reed switch installed in the main body, the float penetrating the main body and moving up and down along the main body, and the reed switch are made to respond. A magnet attached to the float in order to be connected to one side of the body,
In a level switch including a stopper that prevents the float from falling off and a spring that is interposed between the float and the stopper, a surface of the float facing the stopper is parallel to the axis of the main body. A bottomed hole having a different axis is provided, and the stopper is provided with a rod that is loosely inserted into the bottomed hole.

[0020]

In the level switch according to the first aspect of the present invention, the lateral component of the gas flow around the float is unbalanced, the rotational force is generated in the float, and the rotational force is generated in the float itself. Even in this case, the rotation of the float itself is directly restricted by the guide vertical groove provided on the peripheral surface of the float and the guide engaged with the guide vertical groove.

Further, in the level switch according to the second aspect of the present invention, even if a rotational force is generated in the float itself, an axis parallel to the axis of the main body is formed on the surface of the float facing the stopper. The rotation of the float itself is directly regulated by the bottomed hole that it has and the rod that is loosely inserted in the bottomed hole that is provided in the stopper.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the level switch of the present invention is shown in FIG.
Will be explained. FIG. 1 shows the overall structure of a level switch 50 which is an embodiment of the present invention. In FIG. 1, the same components as those of the conventional level switch 31 shown in FIG. 4 are designated by the same reference numerals and the description thereof will be omitted.

On the surface of the float 45 facing the lower flat surface 43c of the lower body 42, a protrusion for preventing the float 45 itself from being in contact with the lower flat surface 43c of the lower body 42. 51 is provided. Further, on the peripheral surface of the float 45, the vertical groove 5 for guide is formed.
2 are provided.

A water passage hole 53 is provided on the surface of the stopper 46 facing the float 45. Therefore, when the water rises and tries to reach the float 45, the water reaches the lower portion of the float 45 through the water passage hole 53 provided in the stopper 46 and acts to raise the float 45 itself. To do. Therefore, as compared with the level switch having no water passage hole 53, the float 45 can be operated more quickly. A cylindrical guide wall 54 is provided on the surface of the stopper 46 facing the float 45, and a part of the tip of the guide wall 54 is provided with a vertical guide wall formed on the float 45. A claw 55 as a guide that engages with the groove 52 is formed so as to extend inward in the radial direction. Therefore, even if a rotational force acts on the float 45 itself, the rotation of the float 45 itself is blocked by the claw portion 55 that engages with the guide vertical groove 52. The guide vertical groove 52 formed in the float 45 and the claw portion 55 of the guide wall 54 provided in the stopper 46 are for preventing the float 45 from rotating, and prevent the float 45 itself from moving up and down. It does not regulate.

The level switch 50 formed in this way
In the above, when the periodic inspection is performed, the accumulator device is degassed, and even if a rotational force is generated in the float 45, the rotation of the float 45 is prevented by the vertical groove 52 for guide formed in the float 45 and the guide provided in the stopper 46. Since it is prevented by the claw portion 55 of the wall 54, damage to the spring 47 can be prevented.

In this embodiment, the vertical groove 52 for the guide is used.
The rotation of the float 45 itself is prevented by directly restricting the rotation of the float 45 itself by the claw portion 55 of the guide wall 54, but the structure of directly restricting the rotation of the float 45 itself is not limited to this. For example, stopper 4
A rod is provided in place of the guide wall 54 on the surface of 6 facing the float 45, and the tip of the rod extends radially inward and engages with the guide vertical groove 52 formed in the float 45. You may form the nail | claw part as a guide. Further, the rod itself may be engaged with the vertical groove 52 for guide without forming the claw portion on the rod.

Next, a second embodiment of the level switch of the present invention will be described with reference to FIGS. 2 is an enlarged cross-sectional view of the float 45 portion of the level switch 60 which is an embodiment of the present invention, and FIG. 3 is a cross-sectional view taken along the line AA of FIG. The structure of the portion of the level switch 60 not shown in FIGS. 2 and 3 is the same as that of FIG. 2 and 3, the same components as those in FIG. 1 are designated by the same reference numerals and the description thereof will be omitted.

The stopper 46 is provided with a pin insertion hole 61 in a direction perpendicular to the axis of the above-mentioned convex portion 43a, and a pin 62 as a guide whose one end projects toward the float 45 is inserted into this hole 61. Has been done.

The stopper 46 is provided at the bottom of the float 45.
Has a bottomed hole 63 larger than the outer diameter of the. Further, the float 45 is provided with a guide vertical groove 64 that opens from the inner peripheral surface of the float 45 toward the outer peripheral surface, and the pin 62 is engaged with the guide vertical groove 64. ing.

The level switch 60 constructed in this way
In the above, even if the accumulator device 2 is degassed at the time of regular inspection, and the rotational force of the float 45 is generated, the rotation of the float 45 itself rotates the pin 62 that engages with the vertical groove 64 for guide provided in the float 45. Therefore, the spring 47 can be prevented from being damaged.

The level switch 60 of this embodiment rotates the float 45 itself by engaging the pin 62 with the vertical groove 64 for the guide that opens from the inner peripheral surface of the float 45 toward the outer peripheral surface thereof. Directly regulated, but float 4
It is also possible to provide a vertical groove for guide only on the side of the inner peripheral surface of 5, i.e. not open to the outer peripheral surface, and engage the pin 62 with this vertical groove.

Further, as a modification of the level switch 60 of this embodiment, instead of the pin 62 and the vertical groove 64, as shown by the broken line in FIG. In addition to providing A, a vertical groove B for guiding is provided on the inner peripheral surface of the float 45, and the protrusion A is engaged with the vertical groove B so that the rotation of the float 45 itself is directly restricted. Good. In the level switch configured as described above, when the water surface reaches the float 45 and the float 45 rises, the protrusion A
The abutment on the bottom C of the float 45 stops the rise of the float 45. Therefore, if the projection A is brought into contact with the bottom C of the float 45 before the float 45 rises and comes into contact with the lower flat surface 43c of the lower main body 42, the projection 51 becomes unnecessary, and It is possible to prevent the float 45 from being kept in contact with the lower flat surface 43c.

Next, a third embodiment of the level switch of the present invention will be described with reference to FIG. FIG. 4 is an enlarged sectional view of the float 45 portion of the level switch 70 which is an embodiment of the present invention. The structure of the portion of the level switch 70 not shown in FIG. 4 is the same as that of FIG. In FIG. 4, the same components as those in FIG. 1 are designated by the same reference numerals and the description thereof will be omitted.

On the surface of the float 45 facing the stopper 46, a bottomed guide hole 71 having an axis parallel to the axis of the convex portion 43a is formed.

A guide rod 72 is provided on the surface of the stopper 46 facing the float 45. The tip side of the rod 72 is loosely inserted into the guide hole 71 provided in the float 45. The rod 72
The outer diameter of is smaller than the inner diameter of the hole 71 of the float 45 so as not to restrict the movement of the float 45.

The level switch 70 thus constructed
In the above, since the degassing from the accumulator device 2 is carried out at the time of the periodic inspection and the rotation force is generated in the float 45, the rotation of the float 45 itself is prevented by the rod 72 loosely inserted in the hole 71 of the float 45. The spring 47 can be prevented from being damaged.

Further, in the level switch 70,
When the water surface rises and reaches the float 45, the air in the bottomed guide hole 71 formed in the float 45 is
Since the water is confined inside the hole 71, the float 45 can be quickly raised by the buoyancy of the air.

[0038]

As described above, in the level switch according to the first aspect of the present invention, the lateral component of the gas flow around the float is unbalanced, the rotational force is generated in the float, and the float is rotated. Even if a rotational force is generated in itself, the rotation of the float itself is directly regulated by the guide vertical groove provided on the peripheral surface of the float and the guide engaging with the guide vertical groove. Therefore, it is possible to prevent the spring from being damaged due to the rotation of the float as in the related art.

Further, in the level switch according to the second aspect of the present invention, even if a rotational force is generated in the float itself, there is a bottomed hole on the surface of the float facing the stopper, and the stopper. The rotation of the float itself is directly regulated by the rod loosely inserted in the bottomed hole provided in the. Therefore, it is possible to prevent the spring from being damaged due to the rotation of the float as in the related art.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a first embodiment of a level switch according to the present invention.

FIG. 2 is a vertical sectional view of a second embodiment of the level switch of the present invention.

3 is a cross-sectional view taken along the line AA of the level switch shown in FIG.

FIG. 4 is a vertical sectional view of a third embodiment of the level switch of the present invention.

FIG. 5 is a diagram showing a specific configuration example of a control rod drive water pressure device in which the level switch of the present invention is used.

FIG. 6 is a vertical cross-sectional view of an example of a conventional level switch.

[Explanation of symbols]

 31, 50, 60, 70 Level switch 40 Body 41 Body upper part 42 Body lower part 44 Guide pipe 45 Float 46 Stopper 47 Spring 48 Magnet 52 Guide vertical groove 54 Guide wall 55 Claw (guide) 61 Pin insertion hole 62 Pin (Guide) 63 hole 64 Vertical groove 71 hole (bottomed hole) 72 Rod

Claims (2)

[Claims] 1. A reed switch installed in the main body, a float penetrating through the main body, and moving up and down along the main body, a magnet attached to the float for reacting the reed switch, A level switch including a stopper connected to one side of the main body for preventing the float from falling off, and a spring interposed between the float and the stopper, wherein a guide is provided on a peripheral surface of the float. And a guide that engages with the guide vertical groove is provided on the stopper or the main body. 2. A reed switch installed in the main body, a float penetrating the main body, and moving up and down along the main body, a magnet attached to the float for reacting the reed switch, A level switch comprising a stopper connected to one side of the main body for preventing the float from falling off, and a spring interposed between the float and the stopper, the level switch facing the stopper of the float. With a bottomed hole having an axis parallel to the axis of the main body on the surface,
A level switch, wherein the stopper is provided with a rod that is loosely inserted into the bottomed hole.