JP2003021259A - Liquid level detection shut-off valve - Google Patents

Abstract

(57) [Problem] To provide a liquid level detection shut-off valve which can be used safely for volatile combustible fluids and can be manufactured at low cost. SOLUTION: A valve body 1 having a main valve seat 4 formed between an inlet side flow path 2 and an outlet side flow path 3, a main valve 5 which comes into contact with and separates from the main valve seat 4, and a main valve 5 are provided. An opening / closing mechanism 7 is provided to move toward and away from the main valve seat 4 according to the position of the float 6. The opening / closing mechanism 7 includes a diaphragm 72 connected to the main valve 5 via a main valve shaft 71, and an inlet-side flow path formed through a through hole 73 formed through the main valve shaft 71 and including the diaphragm 72. 2 and a pilot pressure chamber 74 communicating with the pilot pressure chamber 7.
A pilot valve 77 that opens and closes a communication hole 76 that communicates with the outlet side flow path 3, a spring 79 that constantly urges the pilot valve 77 in a direction that closes the communication hole 76, and is pivotally supported by the valve body 1 and has one end. Is connected to the float 6, and the other end is the pilot valve 7.
7 and a cam lever 81 that opens and closes the pilot valve 77 according to the position of the float 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid level detection shutoff valve. For example, it relates to a liquid level detection shutoff valve used when refueling kerosene or the like from a tank to another container.

[0002]

BACKGROUND ART In regions where a large amount of heating kerosene is used at home, such as in cold regions, as shown in FIG. 3, a large amount of kerosene stocked in a large tank 9 is used in a heating device cartridge or the like. It is often transferred to another container 10 for use. However, when refueling the other container 10 from the tank 9, if the person opens and closes the main valve 23 attached to the tank by visually observing the liquid surface of the container 10, the kerosene will be accidentally overflowed. There are cases. Especially when performing the above work in the darkness at night, it is very difficult because the liquid surface cannot be visually confirmed.

Therefore, kerosene is supplied from the tank 9 to another container 10
An automatic oil supply device has been developed which automatically detects the liquid level in the container 10 and automatically stops the oil supply when the oil is transferred to the container. This is the tank 9 as shown in FIG.
The oil supply pipe 20 is connected to the bottom of the oil supply pipe 20, and a liquid level detecting device 21 including a main valve 23, a solenoid valve 22 and an infrared sensor is provided in the oil supply pipe 20.

In use, when the tip of the oil supply pipe 20 is inserted into the opening 11 of the container 10 and the main valve 23 is opened, kerosene is injected into the container 10. Eventually, when the kerosene in the container 10 reaches a predetermined level and the liquid level is detected by the liquid level detecting device 21, the electromagnetic valve 22 is automatically closed, so that the kerosene can be prevented from overflowing from the container. .

[0005]

However, since the above-described automatic oiling apparatus requires an infrared sensor, a solenoid valve, etc. for detecting the liquid level, it is very costly to manufacture, and it is not suitable for general households. Will be a major obstacle to the spread of. In addition, the above automatic lubricator equipped with an electric system such as an electric current for driving a solenoid valve cannot be used for refueling a volatile combustible fluid such as gasoline due to a risk of ignition or explosion.
There was a problem that the application was restricted. further,
The automatic refueling device consumes a power source such as a battery for driving a solenoid valve each time it is used, so that it costs a lot of money for operation, and when the power is cut off during refueling work, the refueling work is interrupted. It was

Therefore, in view of the above situation, an object of the present invention is that it is safe to use for volatile combustible fluids, can be manufactured at low cost, requires no operating cost, and does not interrupt refueling work. It is to provide a liquid level detection shutoff valve.

[0007]

A liquid level detection shutoff valve according to claim 1 is a valve body having a main valve seat formed between an inlet side flow passage and an outlet side flow passage, and a valve body of the valve body. A main valve that moves toward and away from the main valve seat; a float; and an opening and closing mechanism that moves the main valve toward and away from the main valve seat according to the position of the float. A diaphragm connected to the main valve shaft via a main valve shaft, and a pilot pressure chamber communicating with the inlet-side flow passage through a through hole formed in the valve main body including the diaphragm and penetrating the main valve shaft. A pilot valve that opens and closes a communication hole that connects the pilot pressure chamber and the outlet-side flow path; a biasing unit that biases the pilot valve in a direction in which the pilot valve normally closes the communication hole; Displace the pilot valve depending on the position That it is formed and a linkage mechanism for opening and closing the is characterized in.

According to this structure, when the fluid is supplied from the tank to the container, the interlocking mechanism first keeps the communication hole for communicating the pilot pressure chamber and the outlet side flow path open. In this state, the internal pressure of the pilot pressure chamber drops to the same internal pressure as the outlet side flow passage, so the force applied from the internal pressure of the pilot pressure chamber to the diaphragm is weaker than the internal pressure of the inlet side flow passage applied to the main valve. A main valve connected to a diaphragm forming the pilot pressure chamber via a main valve shaft is separated from the main valve seat. Therefore, the inlet side flow passage and the outlet side flow passage are communicated with each other via the main valve seat, so that the fluid flows out from the inlet side flow passage through the main valve seat to the outlet side flow passage.

Gradually, the container is filled with fluid,
Eventually, the fluid flowing into the container reached a predetermined level,
When the position of the float changes, the pilot valve is displaced via the interlocking mechanism and the communication hole is closed. Since the pilot pressure chamber is communicated with the inlet side flow passage, the internal pressure of the pilot pressure chamber becomes the same as the internal pressure of the inlet side flow passage. At this time, force is applied to the diaphragm by the internal pressure of the pilot pressure chamber, so the main valve connected to the diaphragm via the main valve shaft
It moves with the diaphragm and is seated on the main valve seat. As a result, the inlet-side flow passage and the outlet-side flow passage are blocked, and the supply of fluid is stopped.

By providing the above-mentioned structure, an infrared sensor and a solenoid valve are not required unlike the conventional automatic oiling apparatus, so that the manufacturing cost can be reduced as compared with the conventional method. In addition, it uses a purely mechanical opening and closing mechanism and does not use any electrical system, so it can be safely used with volatile combustible fluids such as gasoline, and since it does not require a power source, it does not consume power every time it is used. There are no operating costs and no interruption of refueling work due to power failure.

Further, in general, since the internal pressure of the inlet side flow passage into which the fluid flows from the tank is high, a large force against the internal pressure of the inlet side flow passage is required to seat the main valve on the main valve seat. . On the other hand, however, because the size of the float is limited due to the relationship with the opening of the container and the specific gravity of kerosene is small, the buoyancy of the float cannot be increased above a certain level, and only the buoyancy of the float is used. It is difficult to securely close the main valve. On the other hand,
In order to achieve the purpose of safe use even with flammable fluids, it is absolutely necessary for the main valve to reliably block the inlet-side flow passage and the outlet-side flow passage to prevent fluid leakage. is there.

In the opening / closing mechanism of the present invention, the diaphragm connected to the main valve via the main valve shaft and the inlet side flow passage via the through hole formed by including the diaphragm and penetrating the main valve shaft. Since it has a communicating pilot pressure chamber, that is, because the pilot pressure chamber and the inlet side flow passage communicate with each other, the main valve is pressed against the main valve seat by utilizing the internal pressure of the inlet side flow passage. Thus, it is possible to reliably block the inlet side flow passage and the outlet side flow passage. Therefore, it is possible to reliably prevent fluid leakage.

Further, if a complicated biasing means having a strong spring or the like is used to press the main valve against the main valve seat against the internal pressure of the inlet side flow passage, the operation of opening the main valve will be carried out this time. Although it is complicated and it is difficult to obtain a smooth opening / closing operation of the main valve, according to the above configuration, the main valve can be reliably closed and the opening operation can be made smooth. In addition, since the pilot valve is provided with an urging means for urging the pilot valve in the direction to always close the communication hole, the communication hole is always closed except when the fluid supply work is performed, and the main valve is connected to the inlet side flow. Since the state in which the passage and the outlet-side passage are blocked can be maintained, fluid can be prevented from leaking and the operation of closing the communication hole by the interlocking mechanism can be speeded up.

In the liquid level detection shutoff valve according to a second aspect of the present invention, the interlocking mechanism according to the first aspect is swingably supported by the valve main body partway and one end is connected to the float via a connecting rod. It has a lever that is connected and has the other end in contact with the pilot valve, and that the distance from the swing support to one end of this lever is formed to be greater than the distance from the swing support to the other end. Characterize.

With such a structure, the position of the float and the opening / closing of the pilot valve can be interlocked by the lever having one end connected to the float via the connecting rod and the other end abutting the pilot valve. At this time, in the lever, the distance from the connection point where the float and the connecting rod are connected to the swing support is longer than the distance from the point where the pilot valve abuts the lever to the swing support. Even if the buoyancy of the float transmitted to the one end of the lever via the connecting rod is small, a force larger than the buoyancy of the float can be applied to the pilot valve by utilizing the lever principle.

Further, when supplying the fluid, the pilot valve must be opened to keep the communication hole open. That is, the pilot valve must be opened to open the communication hole against the urging force that urges the pilot valve to always close the communication hole. Therefore, during fluid supply, the weight of the float exerts a greater force on one end of the lever (float side) than the force exerted by the biasing means on the other end of the lever (pilot valve side) via the pilot valve. There is a need to. However, since it is necessary to use a float having a weight that floats on kerosene or the like having a low specific gravity, there is a limit to making the float heavy. Therefore, by utilizing the lever principle of the lever described above, even if the force of the urging means acts on the other end (pilot valve side) of the lever, the float on the one end side of the lever is floated to kerosene or the like. It can be light.

According to a third aspect of the present invention, there is provided a liquid level detection shutoff valve in which the pilot valve is held at the other end of the lever in a state where a communication hole is opened when the float descends and the float rises. At the same time, a cam that displaces the pilot valve in the direction in which the communication hole closes is formed, and the cam surface where this cam contacts the pilot valve gradually increases the distance from the swing support point to the contact point with the pilot valve when the float rises. It is characterized in that it is formed in a small curved surface shape.

According to this structure, by providing the lever having the cam as described above, the pilot valve is held in the state in which the communication hole is open when the float is descending, and therefore, the above-mentioned configuration is possible. When the fluid flows out from the main valve seat by the opening / closing mechanism, while the float is rising,
Since the lever holds the pilot valve in the direction of closing the communication hole, fluid can be prevented from flowing.

Further, the cam is formed in a curved surface shape in which the distance from the swing support to the contact point with the pilot valve gradually decreases when the float rises, and the urging force for urging the pilot valve is formed. By the action, the contact point between the pilot valve and the cam can slide on the curved surface of the cam, so when the float rises, a slight buoyancy of the float is applied to one end of the cam lever, Once started to rotate, the cam can then smoothly and quickly rotate, causing the pilot valve to close quickly. Therefore, when the fluid in the container reaches a predetermined level and buoyancy acts on the float, the main valve can quickly shut off the inlet side flow passage and the outlet side flow passage to stop the outflow of the fluid.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows a cross-sectional view of the liquid level detection shutoff valve of the present embodiment, and FIG. 2 shows a usage state of the liquid level detection shutoff valve of the present embodiment. As shown in FIG. 1, the liquid level detection shutoff valve of the present embodiment includes a valve body 1 having a main valve seat 4 formed between an inlet side flow passage 2 and an outlet side flow passage 3, and the valve body 1. 1 has a main valve 5 that comes in contact with and separates from the main valve seat 4, a float 6, and an opening / closing mechanism 7 that brings the main valve 5 into contact with and separates from the main valve seat 4 depending on the position of the float 6. ing. Here, the valve body 1 and the float 6 are each made of synthetic resin.

The inlet side flow passage 2 is formed vertically downward, and a main valve seat 4 is provided in the opening on the lower side thereof. The main valve seat 4 has a taper whose inner hole expands downward from the inside of the inlet side flow passage 2, and the taper is formed by a curved surface that curves inward. Further, the main valve 5 has a tapered outer surface which is curved outward so that it is seated on the main valve seat 4, and is made of aluminum.

The outlet side flow path 3 has a bent portion 31 bent like a hook because the opening / closing mechanism 7 is provided inside the valve body 1.
A horizontal portion 32 is provided horizontally from the lower end of the bent portion 31, and a vertical portion 33 is provided vertically downward from the tip of the horizontal portion 32. The lower end of the vertical portion 33 is
An inlet 331 to be inserted into the opening 11 of the container 10 is provided.

The opening / closing mechanism 7 includes a diaphragm 72 connected to the main valve 5 via a main valve shaft 71, and the diaphragm 7
2, a pilot pressure chamber 74 that communicates with the inlet-side flow passage 2 through a through hole 73 that is formed through the main valve shaft 71, and that connects the pilot pressure chamber 74 and the outlet-side flow passage 3. A pilot valve 77 for opening and closing the communication hole 76, and a spring 79 as a biasing means for biasing the pilot valve 77 in a direction in which the pilot valve 77 always closes the communication hole 76,
It has an interlocking mechanism 80 that opens and closes the pilot valve 77 depending on the position of the float 6.

Here, the main valve shaft 71 is integrally formed of aluminum with the main valve 5, has a through hole 73 at the center, and is supported so as to be movable in the vertical direction with respect to the valve body 1. A rubber diaphragm 72 having elasticity is provided on the lower side surface of the main valve shaft 71 so as to extend from the main valve shaft 71 in a direction perpendicular to the axial direction of the main valve shaft 71.
The outer circumference is fixed to the valve body 1. At this time, the diaphragm 72 is sandwiched between the main valve shaft 71 side and the middle of the valve body 1 on both sides by a rigid reinforcing plate 721 made of synthetic resin having a rigidity, and from the end of the reinforcing plate 721 to the valve body. Up to 1, the diaphragm 72 is formed in a shape that is curved upward.

A pilot pressure chamber 74 is provided in the valve body 1 just below the inlet side flow passage 2 and the main valve 5 in a form in which the diaphragm 72 serves as a lid. That is, the pilot pressure chamber 7
4 is always in communication with the inlet side flow passage 2 through a through hole 73 provided in the main valve shaft 71.

A pilot valve seat 75 is formed on the bottom surface of the pilot pressure chamber 74 and directly below the main valve shaft 71 so as to enlarge its inner hole toward the inside of the pilot pressure chamber 74. 75 for pilot pressure chamber 7
A pilot valve 77 made of synthetic resin is provided so as to be seated from the inside of No. 4. The pilot valve 77 has a pilot valve seat 75 that is located outside the pilot pressure chamber 74.
Pilot valve shaft 7 toward the outlet side flow path 3 through the hole
8 is provided in the vertical direction. The pilot valve shaft 78 and the pilot valve 77 are integrally formed of synthetic resin. A spring bearing 791 is provided at an end of the pilot valve shaft 78 opposite to the pilot valve 77 in a direction perpendicular to the axial direction of the pilot valve shaft 78, and the outer wall of the pilot pressure chamber 74 and this spring bearing are provided. 79
A metallic spring 79 is interposed between the valve 1 and the valve 1, and biases the pilot valve 77 in a direction in which the pilot valve 77 is seated on the pilot valve seat 75.

The pilot valve seat 75 has a pilot valve shaft 7
8 apart from the hole through which the pilot pressure chamber 74 and the outlet side flow passage 3 are provided.
Is provided with a communication hole 76. This communication hole 7
The inner diameter of 6 is formed to be slightly larger than the inner diameter of the through hole 73.

The interlocking mechanism 80 includes the horizontal portion 3 of the outlet side flow path 3.
2, a cam lever 81 swingably supported by the valve body 1 and a connecting rod 82 that connects one end of the cam lever 81 and the float 6 are provided. The connecting rod 82 is made of synthetic resin, and the cam lever 81 is made of metal.

The cam lever 81 is swingably supported from below the axis of the pilot valve shaft 78 at a swing support point 811 slightly above the vertical portion 33 of the outlet side flow passage 3, and the horizontal portion 32 of the outlet side flow passage 3 is supported. Inside, it is provided so as to swing about a substantially horizontal line. At this time, the inner diameter of the horizontal portion 32 of the outlet-side flow path 3 is formed to a diameter such that the cam lever 81 does not rotate too much. In addition, the distance from the swing support point 811 of the cam lever 81 to the connection point 812 with the connecting rod 82 is set to be larger than the distance from the swing support point 811 to the point of contact with the pilot valve shaft 78. There is.

The other end of the cam lever 81 (the pilot valve shaft 7
8 side), there is formed a cam 813 which holds the pilot valve 77 in a state where the communication hole 76 is opened when the float 6 descends and displaces the pilot valve 77 in a direction in which the communication hole 76 closes when the float 6 rises. Has been done. This cam 81
The cam surface where 3 abuts on the pilot valve shaft 78 extends from the swing support point 811 when the float 6 rises.
Is formed into a curved surface shape in which the distance to the contact point with and becomes gradually smaller.

The float 6 is in the shape of a capsule of medicine, and the diameter of its cross section fits perfectly in the inlet 331 of the outlet side flow passage 3, and a gap in which a fluid flows is formed between the vertical portion 33 of the outlet side flow passage 3 and the float 6. Although it is provided, it is formed so as not to move largely laterally in the vertical portion 33 of the outlet side flow path 3.

Next, the operation of the liquid level detection shutoff valve will be described. In use, as shown in FIG. 2, the liquid level detection shutoff valve of the present embodiment is connected to the oil supply pipe 20 connected to the bottom surface of the tank 9. Next, after inserting the injection port 331 into the opening 11 of the container 10 with the float 6 lowered, the main valve 23 is opened.

When the float 6 is lowered, the cam lever 81 is rotated counterclockwise in FIG. 1 via the connecting rod 82.
The pilot valve shaft 78 rises up against the urging force of the spring 79 along the cam curved surface of the cam 813, and the pilot valve seat 7
The pilot valve 77 separates from 5. Then, the communication hole 76
Since the fluid in the pilot pressure chamber 74 flows out to the outlet side flow path 3 through the internal pressure of the pilot pressure chamber 74, the internal pressure of the pilot pressure chamber 74 decreases and becomes lower than the internal pressure of the fluid in the inlet side flow path 2. At this time, the main valve shaft 71 is lowered together with the diaphragm 72, and the main valve 5 is separated from the main valve seat 4, so that the inlet side flow passage 2 and the outlet side flow passage 3 are communicated with each other and the fluid flows. Therefore, when the float 6 is lowered, the fluid flows and the container 10 is filled with the fluid.

When the container 10 is filled with the fluid and the liquid surface of the fluid reaches the position of the float 6, the float 6 gradually rises due to buoyancy. When the float 6 starts to rise, the cam lever 81 rotates clockwise in FIG. 1 via the connecting rod 82, so that the pilot valve shaft 78 and the pilot valve 77 descend downward along the cam curved surface of the cam 813, and further, The pilot valve 77 is seated on the pilot valve seat 75 by the bias of the spring 79 provided on the spring receiver 791.

Since the pilot pressure chamber 74 is communicated with the inlet side flow passage 2 by the through hole 73 provided in the main valve shaft 71, the internal pressure of the pilot pressure chamber 74 becomes the same as the internal pressure of the inlet side flow passage 2. . Further, since the main valve shaft 71 is connected to the diaphragm 72 and the area of the diaphragm 72 is much larger than the area of the main valve 5 facing the inlet side flow passage 2,
The difference between the force received by the diaphragm 72 from the pilot pressure chamber 74 and the force received from the upper side of the pilot pressure chamber 74 is
Is larger than the force received from the inlet side flow path 2.
Therefore, the main valve 5 is pushed up by the force received by the diaphragm 72, seats on the main valve seat 4, and shuts off the inlet side flow passage 2 and the outlet side flow passage 3. That is, float 6
The fluid flow is stopped in the state that the
Refueling is stopped when the fluid is filled to 0 to a predetermined level.

According to this embodiment, the following effects can be obtained. By providing the pilot pressure chamber 74 provided with the diaphragm 72, even if the buoyancy of the float 6 is small, the internal pressure of the inlet side flow passage 2 is drawn into the pilot pressure chamber 74 from the through hole 73 provided in the main valve shaft 71. Then, push up the main valve shaft 71 together with the diaphragm 72,
The main valve 5 can be seated on the main valve seat 4 to reliably shut off the inlet side flow passage 2 and the outlet side flow passage 3.

The main valve seat 4 provided at the opening of the inlet-side flow passage 2 has a curved inner surface whose inner hole expands from the inside of the inlet-side flow passage 2 toward the opening and is curved inward. Since the main valve 5 is formed with a tapered outer surface with its tip end curved outward so as to be seated on the main valve seat 4, when the main valve 5 is seated on the main valve seat 4, Even if the main valve 5 is slightly inclined with respect to the main valve seat 4, the main valve 5 slides along the curved surfaces of each other, and the direction thereof can be changed to the direction in which the main valve seat 4 is accurately seated. Therefore, the inlet side flow path 2
Therefore, the outlet-side flow path 3 can always be reliably blocked, and the fluid can be prevented from leaking.

Further, since the main valve seat 4 is made of synthetic resin, the main valve seat 4 and the main valve 5 are in close contact with each other without any gap,
When the valve is closed, the inlet side flow passage 2 and the outlet side flow passage 3 can be reliably shut off so that the fluid does not leak.

On the cam lever 81, the swing support point 81
The distance from 1 to the connection point 812 with the connecting rod 82 is from the swing support point 811 to the pilot valve shaft 78 of the pilot valve 77.
Since the cam lever 81 is provided so as to be larger than the distance to the point where it abuts on the pilot valve shaft, the buoyancy of the float 6 is set on the basis of the swing support point 811 as a fulcrum by the lever principle utilizing the difference in this distance. It becomes possible to act on the point of contact with 78 according to the lever ratio,
The buoyancy of the float 6 can also push up the pilot valve 77.

On the contrary, by utilizing the lever principle of the cam lever 81, even if the urging force of the spring 79 acts on the other end (pilot valve shaft 78 side) of the cam lever 81, one end of the cam lever 81 The float 6 connected to the side via the connecting rod 82 may be light enough to float on kerosene or the like.

Further, the cam 813 of the cam lever 81 is formed in a curved surface shape in which the distance from the swing support point 811 to the contact point with the pilot valve shaft 78 gradually decreases when the float 6 rises. Since the spring 79 provided on the shaft 78 biases the pilot valve 77 in the closing direction, when the float 6 rises, the contact point with the pilot valve shaft 78 slides on the curved surface of the cam 813,
It is possible to rotate the cam lever 81 and quickly close the pilot valve 77. This means that the tangential component of the force exerted by the pilot valve shaft 78 on the cam lever 81 acts in the direction opposite to the swing support point 811, and the cam lever 81 acts as a pilot centering on the swing support point 811. This is because torque that rotates toward the valve shaft 78 is generated. That is, when the container 10 is filled with the fluid to a predetermined level and the float 6 starts to rise, the pilot valve 77
Can be closed immediately to stop fluid flow quickly.

The horizontal portion 32 of the outlet side flow path 3 in which the cam lever 81 exists is formed with an inner diameter such that the cam lever 81 does not rotate too much. Therefore, the inner wall of the outlet-side flow path 3 can play a role of a stopper with respect to the cam lever 81. Therefore, when the float 6 is pulled down or pushed up too much, excessive force is applied to the cam lever 81 and the swing support point 811. It is possible to prevent it.

Further, the inlet side flow passage 2 is in the vertical direction,
The main valve 5 is formed so as to push up the main valve seat 4 from below,
The opening / closing mechanism 7 can be housed compactly by adopting a positional relationship in which the pilot pressure chamber 74 is provided immediately below the main valve 5. And the float 6 and the connecting rod 8
2. The compact shape can also be achieved by providing the cam lever 81 inside the outlet side flow path 3.

Since the liquid level detecting shutoff valve of this embodiment does not require an infrared sensor or a solenoid valve, the present invention can be manufactured at a far lower cost than the conventional manufacturing cost, and moreover, it is purely mechanical. Since it uses only the mechanism and does not use any electric system, it can be safely used for volatile combustible fluids such as gasoline, and since it does not require a power source,
There is no operating cost due to power consumption each time it is used, and there is no interruption of refueling work due to power failure.

The liquid level detecting shutoff valve of the present invention is
Of course, the present invention is not limited to the above-mentioned embodiments, and it is needless to say that various modifications can be made without departing from the scope of the present invention. For example, the float 6 need only float on the fluid and may be formed of expanded polystyrene.
Further, the cam lever 81 may be made of rigid synthetic resin instead of metal.

[0046]

As described above, according to the liquid level detection shut-off valve of the present invention, it is safe to use for volatile combustible fluid, can be manufactured at low cost, requires no operating cost, and can be refueled. It is possible to achieve an excellent effect that the above is not interrupted.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of one embodiment of the present invention.

FIG. 2 is a diagram showing a usage state of the embodiment.

FIG. 3 is a diagram showing a conventional oil supply method.

FIG. 4 is a diagram showing a conventional automatic oil supply apparatus and an oil supply method.

[Explanation of symbols]

1 valve body 2 Inlet side flow path 3 outlet side flow path 4 main seat 5 Main valve 6 floats 7 open / close mechanism 71 Main valve shaft 72 diaphragm 73 Through hole 74 Pilot pressure chamber 76 communication hole 77 Pilot valve 79 spring (biasing means) 80 interlocking mechanism 81 Cam lever 82 connecting rod 813 cam

Front page continuation (51) Int.Cl. ⁷ Identification code FI theme code (reference) G05D 9/02 G05D 9/02 AF terms (reference) 3E083 AA01 AB08 AD18 AE07 3H055 AA02 AA22 BA12 CC02 CC21 DD22 EE05 FF11 3H068 AA01 BB52 BB74 DD01 EE20 EE22 GG07 5H309 AA11 BB03 BB16 CC09 DD24 DD27 EE06 FF04 FF06 FF20 GG03 JJ02 KK08

Claims (3)

[Claims] 1. A valve main body having a main valve seat formed between an inlet-side flow passage and an outlet-side flow passage, a main valve that comes into contact with and separates from the main valve seat of the valve main body, a float, and the float. An opening / closing mechanism for bringing the main valve into and out of contact with the main valve seat according to the position of, and the opening / closing mechanism includes a diaphragm connected to the main valve via a main valve shaft, and the diaphragm. A pilot pressure chamber communicating with the inlet side flow passage through a through hole formed in the valve body and penetrating the main valve shaft; and a communication hole communicating the pilot pressure chamber and the outlet side flow passage. A pilot valve that opens and closes, and a biasing means that biases the pilot valve in a direction in which the pilot valve constantly closes the communication hole,
A liquid level detection shut-off valve, which is formed by including an interlocking mechanism that displaces the pilot valve according to the position of the float and opens and closes the communication hole. 2. The liquid level detection shutoff valve according to claim 1, wherein the interlocking mechanism is supported swingably by the main body partway, and one end thereof is connected to the float via a connecting rod. In addition, the other end has a lever in contact with the pilot valve, and the distance from the swing support to the one end of the lever is formed to be larger than the distance from the swing support to the other end. Liquid level detection shutoff valve. 3. The liquid level detection shutoff valve according to claim 2, wherein the other end of the lever holds the pilot valve in a state where the communication hole is opened when the float descends, and
A cam for displacing the pilot valve in a direction in which the communication hole closes when the float rises is formed, and a cam surface on which the cam abuts the pilot valve is formed from the swing support to the pilot valve when the float rises. A liquid level detection shutoff valve characterized in that it is formed in a curved surface shape in which the distance to the contact becomes gradually smaller.