JPH1038123A - Bidirectional cutoff valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately sense opening/closing conditions of a power-saved bidirectional cutoff valve by arranging a magnetic flux sensing means on a bobbin for sensing leakage of the magnetic flux through a gap between a rear end of a plunger and a fixed iron core. SOLUTION: A plunger 7 is inserted into a guide pipe 5 arranged inside a cylinder of a bobbin 6. The plunger 7 precisely passes a center portion during a stroke of cutoff and resetting. A lead switch LS is arranged between the bobbin 6 of a coil 9 and the non-magnetic guide pipe 5 inserted into the central hole of the bobbin 6 for sensing the position of the plunger 7. The switch is arranged on a gap-forming portion between a fixed iron core 4 and the plunger 7. Since the lead switch LS is arranged near an abutting surface of the plunger 7 and the fixed iron core 4, switching can be carried out while reacting minute leakage of magnetic flux.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of a gas shutoff valve mounted on a gas meter or the like, and more particularly, to a bidirectional shutoff valve capable of realizing high airtightness while saving power.

[0002]

2. Description of the Related Art A gas meter provided for each consumer such as a home measures the amount of gas consumed by the consumer,
When an abnormal gas flow rate is detected or an earthquake is detected, a safety function for closing a shutoff valve provided in the gas pipe is provided.

[0003] Conventionally, a gas shut-off valve generally provided in a gas meter can only be driven in one direction to close the shut-off valve in response to a shut-off command signal from a microcomputer. Therefore, an artificial operation such as manually pressing a return button is required to return the shut-off valve.

Therefore, in recent years, it has been proposed that the gas shutoff valve can be driven bidirectionally. If it is possible to drive in both directions, for example, if gas leakage is detected by a microcomputer after shutting off and gas leakage is not detected, the shutoff valve is returned by a return command signal from the microcomputer without performing an artificial check ( Open).

[0005] At that time, the microcomputer of the gas meter sends the shutoff command signal and the reset command signal to the shutoff valve to perform shutoff and return. In order to confirm that the valve has been shut off or restored, a position detecting element of the valve element is provided near the shut-off valve.

[0006]

However, there are some problems to be solved in order to form a shut-off valve which can be driven in both directions. First, airtightness at the time of shutoff, which is a basic function as a shutoff valve, must be sufficiently increased. Second, the current flowing through the coil must be reduced as much as possible to save power. In particular, it is important not to increase the drive current at the time of return in the case of a two-way valve.

For this reason, in the two-way shut-off valve, it is necessary to increase the magnetic efficiency by reducing the gap between the fixed core and the plunger, which is inserted into the coil and sent out and inserted by the magnetic force of the coil, to reduce the leakage flux. is there.

Generally, in a conventional one-way shut-off valve, a reed switch for switching based on the presence or absence of the leakage magnetic flux is provided near the outside of the shut-off valve as a position detecting element of a valve body. However, if the leakage flux is reduced as much as possible to save power in the bidirectional shutoff valve as described above, the open / closed state of the valve cannot be detected by the conventional reed switch.

An object of the present invention is to provide an improved structure capable of reliably detecting the open / close state of a power-saving bidirectional shutoff valve.

[0010]

SUMMARY OF THE INVENTION According to the present invention, there is provided, in accordance with the present invention, a bidirectional movement of a valve element supported by a tip of a plunger inserted in a coil by supplying current to the coil. The two-way shut-off valve has a bobbin around which the coil is wound, and a magnetic pole that houses the bobbin and the coil, and the bobbin is provided with a leakage magnetic field of a gap between a rear end of the plunger and a fixed iron core. This is achieved by providing a two-way shut-off valve, wherein the magnetic flux detecting means for detecting is mounted on the bobbin.

[0011] In particular, the present invention relates to a case where the lower end of the plunger abuts on the upper end of the fixed iron core, and when the cross-sectional shape of the abutting portion has an oblique side in the axial direction of the plunger, a minute distance from the side is obtained. The leakage magnetic field can be detected by the magnetic flux detection means embedded in the bobbin. In addition, since it is provided in the magnetic pole, the influence of an external magnetic field can be eliminated.

The magnetic flux detecting means is, for example, a reed switch, and is attached or embedded at a position adjacent to the gap portion of the bobbin. Or
The magnetic flux detecting means is attached to or embedded in the bottom of the bobbin.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. However, the technical scope of the present invention is not limited to the embodiment.

FIG. 1 is a (A) top view, (B) side view, and (C) bottom view of a structure combining two two-way shutoff valves. Although a combination of a valve with a large diameter and a valve with a small diameter is used, the present invention can of course be applied to a single case. The two-way shutoff valve in FIG. 1 includes a mounting part 32 fixed to a mounting surface on the gas meter side, and a coil part 30 for moving a plunger supporting a valve body part 34 in two directions.

FIG. 2 is a sectional view taken along the line A--
It is sectional drawing which respectively shows A 'and BB'. The two shut-off valves have the same structure except that the diameter of the valve body 34 is different as described above. FIG. 3 is an enlarged cross-sectional view showing a state where the shut-off valve on the cross section AA ′ side is attached to the gas meter and the valve is open. The structure of the shut-off valve will be described with reference to both drawings.

Reference numerals 1 and 3 denote yokes which become magnetic poles of the coil 9 and are caulked to the flange 2 of the mounting plate fixed to the mounting seat 23 on the gas meter side with screws or the like. A bobbin 6 around which a coil 9 is wound is provided in the magnetic poles 1 and 3.
Is stored. A fixed core 4 and a permanent magnet 18 below the fixed core 4 are provided at the center of the coil 9.
A plunger 7 which is a movable iron core is mounted on the top. Reference numerals 19 and 20 denote O-rings for obtaining airtightness of the gas flow path.

The plunger 7 is inserted into a guide pipe 5 mounted in the cylinder of the bobbin 6, so that the plunger moves accurately at the center during the shut-off and return strokes. This will be described later.

A pilot pin 1 is provided above the plunger 7.
0 is screwed and attached, and a valve structure is inserted between the head of the pilot pin 10 and the plunger 7. The valve structure includes a spacer 12, a sub-valve seat (pilot valve-like rubber valve seat) 15, a support disk (valve element) 8, a rubber valve seat 14 placed on the disk, and the valve from below. It is composed of a holding disk 22 for holding the sheet.

The taper spring 1 for pressing the valve body 8 and the valve seat 14 on the flange 2 through the spacer 12 and the sub-valve seat 15 against the valve seat 24 of the gas meter.
A sub-spring (spring for pilot valve) 17 is also provided between the support disk 8 and the head of the pilot pin 10.

Further, as shown in FIG. 3, a lead for detecting the position of the plunger 7 between the bobbin 6 of the coil 9 and the nonmagnetic guide pipe 5 inserted in the center hole of the bobbin. A switch LS is provided. Moreover, the position is where the gap between the fixed iron core 4 and the plunger 7 is formed.

The bobbin 6 and the guide pipe 5 are made of a non-magnetic material,
For example, it is formed of plastic, and the position shown in FIG.
Ideal for detecting the presence or absence of magnetic flux leakage. Further, as described later, in order to minimize the leakage magnetic flux, the plunger 7 has a trapezoidal cross-sectional structure as shown by 40 in the figure.
And the contact surface of the fixed iron core 4 is machined. However, by providing the reed switch LS in the vicinity thereof, switching can be performed in response to the presence or absence of minute leakage magnetic flux.

FIG. 4 is a sectional view when the shut-off valve is closed. FIG. 5 is a cross-sectional view in the process of returning (opening) the shutoff valve. Hereinafter, the opening and closing operation of the shutoff valve will be described with reference to FIGS. 4 and 5 show an example in which the reed switch LS is embedded in the center hole of the bobbin 6. If the bobbin 6 has a sufficient thickness, the embedded portion of the reed switch can be easily formed by molding.

[Valve Opening State] As shown in FIG. 3, the plunger (movable iron core) 7 is attracted through the fixed iron core 4 by the downward magnetic force of the permanent magnet 18 in the drawing. This downward magnetic force is applied to the spacer 12 by the taper spring 16.
Through the force to push the plunger 7 upward. Conversely, the suction between the plunger 7 and the fixed iron core 4 cannot be separated only by the pushing force of the taper spring 16. The spacer 12 is fixed integrally with the pilot pin 10 and the plunger 7 by screwing the pilot pin 10 to the plunger 7.

As described above, when the valve is open, it is maintained only by the magnetic force of the permanent magnet 18, no current flows through the coil 9, and the coil 9 is used without power.

When the valve is open, the magnetic flux generated by the permanent magnet 18 is concentrated in the closed magnetic flux circuit of the fixed iron core 4, the plunger 7, and the magnetic poles 1, 3, so that there is no gap between the fixed iron core 4 and the plunger 7. Since there is no leakage magnetic flux, the reed switch LS is off.

[Operation of Valve Shutdown] When a microcomputer (not shown) mounted on the gas meter detects an abnormal gas flow rate or an earthquake, it issues a shutoff command signal and sends a drive current from a coil lead-out terminal 9a to cause the coil 9 to operate. To generate a magnetic force to apply an upward force Fx to the plunger 7. The total force of the force Fx by the coil and the upward force F1 by the taper spring 16 exceeds the downward force Fm by the magnet 18, and the plunger 7 moves upward. Then, the valve seat 14 is pressed against the valve seat 24 by the upward force F1 by the taper spring 16, and the gas flow is shut off.

When the valve shown in FIG. 4 is closed, a gap dx is formed between the plunger 7 and the fixed iron core 4, from which the static magnetic flux of the permanent magnet 18 leaks to turn on the reed switch LS. . Therefore, the microcomputer (not shown) can detect from the signal from the reed switch LS that the valve has been reliably shut off.

In this embodiment, the taper spring 16 and the guide pipe 5 are provided in order to save power and achieve high airtightness. The damper spring 16 applies an upward force F <b> 1 inclined toward the center of the plunger 7 to the spacer 12. Therefore, an upward force can be uniformly applied to the circumferential end portion of the valve seat 14, and the valve element 8 can be moved to the position shown in FIG.
It is prevented that the valve seat 24 comes into contact with the valve seat 24 obliquely in the direction of the arrow A inside. Therefore, high airtightness can be obtained.

Further, since the taper spring 16 does not contact the guide pipe 5, it does not cause unnecessary sliding resistance in the piston movement of the plunger 7. Further, the spacer 12 can be made smaller in diameter as compared with the case where a parallel spring is used, and the gas pressure resistance can be reduced at the time of the return operation as described later. This means that the current value given to the coil 9 can be made as small as possible.

The guide pipe 5 is provided with a mounting plate (flange).
2 and is provided so as to protrude therefrom. In FIG. 4, the plunger 7
Moves vertically, but depending on the gas meter, a shut-off valve may be attached so that it moves horizontally. In this case, the weight of the valve body may fall in the direction of arrow A in FIG. Such a fall means that the valve seat 14 and the valve seat 24 are caused to have uneven airtightness, and in the worst case, the valve seat 14 may not partially come into contact with the valve seat 24. . Therefore, the provision of the guide pipe 5 as a guide for the plunger 7 prevents the valve element from falling down. In addition, the fall of the valve element causes an increase in the pulling force and an increase in sliding resistance by the coil 9, which is harmful to power saving.

[Valve Opening (Returning) Operation] FIG. 5 is a sectional view showing a state during the valve opening operation. The return operation of the valve is performed by flowing a current through the coil 9 in a direction opposite to that at the time of interruption, thereby applying a downward force Fy in the figure to the plunger 7 to overcome the upward force of the taper spring 16, It is adsorbed to the fixed iron core 4.

In the present embodiment, the tapered spring 16
By using the pilot pin 1 as described above,
The diameter of the spacer 12 corresponding to the zero valve seat can be reduced. As shown in FIG. 4, when the valve is shut off, an upward gas pressure is applied to the support ring 8, which is a valve element. Therefore, to return the valve,
The coil 9 must generate a downward force that exceeds the back pressure of this gas. Then, it is necessary to supply a very large current to the coil 9, which hinders power saving.

Then, by utilizing the structure of the pilot pin 10, as shown in FIG. 5, only the pilot pin 10 is first moved downward by the downward force Fy by the coil 9, and the pilot The contact between the valve seat 8A and the valve seat 15 for the pilot valve is released. As a result, the gas escapes from between the pilot pin 10 and the support disk 14 so that the gas back pressure applied to the support disk 14 is reduced. In this case, in this embodiment, by providing the tapered spring 16, the spacer 1 serving as the valve seat is more used than a parallel spring.
2 can be reduced in diameter, and the current value of the coil required for the first stroke by the pilot pin 10 can be reduced. This contributes to power saving.

Thereafter, the support disk 8 is also pulled downward by the head of the pilot pin 10, and the valve is opened as shown in FIG.

The above-mentioned improvement for power saving at the time of the valve returning operation is also applied to the shapes of the lower end of the plunger 7 and the upper end of the fixed core 4. That is, as shown by the broken line 40 in FIG. 3, the suction shapes of both are processed into a substantially trapezoidal shape. As shown in FIG. 4, the gap in the closed magnetic flux loop formed by the plunger 7 as the movable core, the fixed core 4 and the yokes 1 and 3 as the magnetic poles is reduced as much as possible to reduce the leakage flux and increase the magnetic efficiency. ing. As shown in FIG. 4, d is a distance required for the plunger 7 to vertically move, but is processed into a trapezoidal shape.
The substantial gap can be as narrow as dx. As a result, the leakage of magnetic flux is reduced, the magnetic efficiency is increased, and it is possible to contribute to power saving.

Although the shape in which the leakage magnetic flux is suppressed to increase the magnetic efficiency as described above, as described above, in the present invention, since the reed switch LS is provided adjacent to the gap portion, the leakage current is small. Can also be reliably detected.

[Shape of Valve Seat] Returning to FIG.
The improvement of the shape of the valve seat for high airtightness will be described. Normally, the time when the shut-off valve waits in the open state in FIG. 3 is the longest. At that time, for example, a gas flow is generated from the left side of the drawing to the right side. Due to this gas flow, the valve seat 14 of the valve element is partially turned up. The valve seat 14 is simply mounted on the supto disk 8 so that airtightness can be obtained in a closed state as shown in FIG. In this way, the gap between the valve seat 14 and the support disk 8 ensures uniform close contact with the valve seat 24 at the circumferential end. However, due to the gap, the circumferential end 14B of the valve seat 14 is turned up by the gas flow shown in FIG. As a result, the shape of the valve seat 14 is deformed, and the close contact with the valve seat 24 at the time of shutoff is deteriorated. This is a bad effect of high airtightness.

Therefore, in the present embodiment, a downward rib structure is formed at the circumferential end 14B of the valve seat 14 as shown in FIG. By doing so, the strength of the circumferential end is increased, and the phenomenon of the swelling can be prevented.

Alternatively, although not shown, the valve seat 14
By turning the circumferential end 14B of the support disk 8 into a U-shape and covering the circumferential end of the support disk 8 with the U-shaped valve seat 14, the above-mentioned turning up can also be prevented. However, in the case of a U-shape, the assembling process becomes somewhat complicated.

[Replaceable Spacer] Another improvement in power saving is that a replaceable spacer 12 is provided between the sub-valve seat 15 as a pilot valve seat and the plunger 7. FIG. 6 is a cross-sectional view showing a valve open state when the thickness W2 of the spacer 12 is reduced.
FIG. 7 is a cross-sectional view showing a valve closed state when the thickness W2 of the spacer 12 is similarly reduced.

As shown in FIG. 6, when a shut-off valve is installed in the gas flow path in the gas meter, the length H from the mounting plate 2 of the shut-off valve to the valve seat 24 of the gas meter varies depending on the capacity of the gas meter. Therefore, the length d of the vertical stroke of the plunger 7 supporting the valve element 8 also needs to be different depending on the length H. Therefore, the gap d between the plunger 7 and the fixed iron core 4 when the valve is closed as shown in FIG.
Will be different as well. As a result, it is necessary to change the drive current value flowing through the coil 9 when the valve is closed according to the capacity of the gas meter. When the capacity of the gas meter is large, the diameter H of the gas flow path also increases, the gap d increases, and the coil current for drawing in the plunger 7 increases. This is a bad effect of power saving.

Therefore, in the present embodiment, even if the diameter H on the gas meter side is different, the replaceable spacer 12 is provided so that the length of the stroke of the valve body, that is, the gap d can be set to the same minimum value. Provided. When the diameter H is large, as shown in FIG.
1 and the diameter H is small, the thickness W2 of the spacer 12 is reduced as shown in FIG. as a result,
The stroke length d of the valve body is always constant, and the gap d between the plunger 7 and the fixed iron core 4 at the time of shutoff can be kept to a minimum value. Therefore, the draw current of the plunger can be minimized, and the power consumption can be reduced.

As described above, by reducing the diameter of the spacer 12 and reducing the back pressure due to the gas pressure applied to the spacer 12 serving as the pilot valve seat, it is possible to reduce the plunger retraction force at the time of return. it can.

As described above, by making the stroke length of the plunger 7 constant, the amount of magnetic flux leaking from the permanent magnet 18 can be made constant. As a result, the reed switch LS
Can be made constant irrespective of the capacity of the gas meter, and the accuracy of valve position detection is improved.

[Other Embodiments] FIG. 8 is a sectional view of a shut-off valve according to another embodiment. FIG. 9 is a plan view thereof. In this embodiment, a reed switch LS for detecting the position of the plunger 7 is embedded in a thick portion at the bottom of the bobbin 6. In the examples shown in FIGS. 3, 4, and 5, the core is embedded in the bobbin 6 adjacent to the gap between the iron cores.
However, in order to effectively give the effect of the partial coil 9 to the plunger 7, the thickness is formed thin, so that it is difficult to mount the reed switch, and it is also difficult to take out the lead wire (not shown) of the reed switch. It is.

Therefore, in this embodiment, the reed switch is buried in the thick portion at the bottom of the bobbin 6. Even at this position, since it is inside the magnetic poles 1 and 3 surrounding the coil, it is possible to effectively detect the magnetic flux leakage from the gap dx between the iron cores. In the plan view of FIG. 9, a part of the magnetic pole 3 is removed for explanation.

Further, as in the embodiment shown in FIGS. 3, 4, and 5, the reed switch LS is provided in the magnetic poles 1 and 3, so that the influence of an external magnetic field can be reduced, and The switch detection accuracy can be improved.

[0048]

As described above, according to the present invention, even if the gap dx between the plunger 7 and the fixed core 4 is made as small as possible in the bidirectional shut-off valve with improved power saving. Since a detector that responds to leakage magnetic flux from the gap, for example, a reed switch is mounted on the bobbin in the magnetic pole that houses the coil, the presence or absence of minute leakage magnetic flux can be reliably detected.

Further, when the reed switch is mounted at the position of the gap formed between the plunger 7 of the bobbin and the fixed iron core 4, the minute leakage magnetic flux can be detected most sensitively.

[Brief description of the drawings]

1A is a top view, FIG. 1B is a side view, and FIG. 1C is a bottom view of a structure in which two two-way shutoff valves are combined.

FIG. 2 is a cross-sectional view taken along a line AA ′ and a line BB ′ in a top view of FIG.
FIG.

FIG. 3 is an enlarged cross-sectional view showing a state where a shut-off valve is attached to a gas meter when the valve is open.

FIG. 4 is a cross-sectional view when a shut-off valve is closed.

FIG. 5 is a sectional view in the middle of returning (opening) a shutoff valve.

FIG. 6 is a cross-sectional view showing a valve opened state when the thickness W2 of the spacer 12 is reduced.

FIG. 7 is a cross-sectional view showing a valve closed state when the thickness W2 of the spacer 12 is reduced.

FIG. 8 is a cross-sectional view of a shut-off valve according to another embodiment.

FIG. 9 is a plan view of FIG.

[Explanation of symbols]

 1, 3 magnetic pole 2 flange 4 fixed iron core 5 guide pipe 6 bobbin 7 plunger 8 valve body 9 coil 10 pilot pin 12 pilot valve seat, spacer 14 valve seat 16 taper spring 18 magnet 24 valve seat LS reed switch, valve position detector

 ──────────────────────────────────────────────────続 き Continuation of the front page (72) Hideo Kato Inventor 6-2, Kawaradai 959-2, Kurihashi-cho, Kita-Katsushika-gun, Saitama Pref. Inside Nikkoshi Co., Ltd. (72) Inventor Yoshikatsu Mikage 1-6-1, Nihonbashi Honcho, Chuo-ku, Tokyo Nikkoshi Co., Ltd.

Claims (5)

[Claims] 1. A bidirectional shut-off valve for moving a valve body supported by a tip of a plunger inserted in a coil bidirectionally by supplying a current to the coil, comprising: a bobbin around which the coil is wound; A magnetic pole for accommodating the bobbin and a coil, wherein the bobbin is provided with magnetic flux detecting means for detecting a leakage magnetic field in a gap between a rear end of the plunger and a fixed iron core. And a two-way shut-off valve. 2. The two-way shut-off valve according to claim 1, wherein a lower end portion of the plunger is in contact with an upper end portion of the fixed core, and a cross-sectional shape of the contact portion has an oblique side in the axial direction of the plunger. It is characterized by the following. 3. The two-way shutoff valve according to claim 1, wherein said magnetic flux detecting means is a reed switch. 4. The two-way shut-off valve according to claim 1, wherein said magnetic flux detecting means is mounted or embedded at a position adjacent to said gap portion of said bobbin. 5. A two-way shut-off valve according to claim 1, wherein said magnetic flux detecting means is attached to or embedded in a bottom portion of said bobbin.