JP2000170937A - Flow velocity detecting mechanism - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a flow velocity detecting mechanism capable of avoiding instant moving of a sensor lever and surely preventing the generation of malfunction due to unwilling rotation of the sensor lever, even if external factors such as violent pitching and rolling and contact with other members are applied on the sensor lever. SOLUTION: Among a lower end part of a hood 12, a fulcrum part 14A in a sensor lever 14 and a balance weight 15, a damper 70 is provided. The damper 70 has a function buffering external factors applied on the sensor lever 14 for short time, avoiding instant moving of the sensor lever 14 and allowing the rotation of a flow sensor 11 and the sensor lever 14 by continuity of flow velocity of a set value or more.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flow velocity detecting mechanism attached to an emergency shutoff valve for urgently shutting off a pipeline when, for example, an earthquake occurs.

[0002]

2. Description of the Related Art Conventionally, in the event of an emergency when a water distribution pipe functioning as a fluid passage is damaged by an earthquake, an emergency shutoff valve has been devised so as to automatically shut off the flow of water through the fluid passage. The emergency shutoff valve shown in FIG. 3 is known. In this figure, 1 is a valve box, 2 is a valve body,
Reference numeral 3 denotes a valve stem, and pipes 4A and 4B are provided at both ends of the valve box 1.
Is connected, and when the valve body 2 is opened as shown in the figure, water passes in the direction from the pipe 4A to the pipe 4B as indicated by an arrow F. On the other hand, the closed state of the fluid passage can be obtained by rotating the valve body 2 fixed to the valve rod 3 together with the valve rod 3 about 90 degrees about its axis and closing the valve. This type of emergency shutoff valve includes a flow velocity detection mechanism 10, an engagement / disengagement mechanism 20, a rotation mechanism 30, a torque generation source 40, and a link mechanism 50.

[0003] The flow velocity detecting mechanism 10 is configured to detect the flow velocity of the passing water flow F and operate when the flow velocity reaches a set value. That is, as shown in FIGS. 3 to 6, a vertical flow sensor 11 protruding into the valve box 1,
A horizontal sensor shaft 13 supported horizontally and rotatably in a hood 12 which is mounted on the valve box 1 in a watertight manner, and a fulcrum 1 at an end of the sensor shaft 13 outside the hood 12.
Sensor lever 14 to which 4A is fixed, sensor lever 14
The balance weight 15 fixed to one end of the fulcrum part 13A at the point, and the fulcrum part 14A at the sensor lever 14
And a sensor weight 16 attached to the sensor lever 14 so as to be slidable and positionable in the direction of the arrow X, and the upper end (base end) of the flow sensor 11 is fixed to the sensor shaft 13. ing.

As shown in FIGS. 3 to 6, the engagement / disengagement mechanism 20 includes a vertical rod 21 and a bell-crank-shaped latch lever connected to and linked to a lower end of the rod 21.
22. The upper end of the rod 21 is pivotally movable via a pin 23 at a fulcrum 14A of the sensor lever 14.
The lower end is connected to the distal end of the one-side extension 22A of the latch lever 22. The latch lever 22 is rotatably supported by the pin 22B, and is provided with an engaging claw 22d at the distal end of the other side extension 22D.

The rotation mechanism 30 is shown in FIGS. 3, 4, 7, and 8.
As shown in FIG. 9, the latch 31, the weight 32,
A striker 33 is provided. The latch 31 is fixed to one end of a shaft 34, and the shaft 34 is horizontally and rotatably supported by bearings 6, 6 provided on an upper portion of the cylinder base 5. Thereby, when the latch 31 rotates together with the shaft 34, the tip claw portion 31A has an
The latch lever 22 is detachably engaged with the engaging claw 22d. The weight 32 is fixed to the other end of the shaft 34 via a lever 35 extending obliquely upward. The striker 33 includes a pair of left and right arm portions 33A, 33A extending diagonally downward and facing each other, and a horizontal striking pin 33B connecting the lower ends of these arm portions 33A, 33A to each other. The upper ends of the arm portions 33A, 33A are fixed to the shaft 34 between the bearings 6, 6.

[0006] As shown in FIG.
It is constituted by a weight 42 attached to one end of the valve stem 3 via a lever 41. The link mechanism 50 is
As shown in FIGS. 3, 7, 9, and 10, a first link 51, a second link 52, and a lever 53 are provided. The distal end of the first link 51 is rotatably supported by a fixing member 55 via a horizontal pin 54, and the rear end is articulated to the distal end of the second link 52 via a horizontal pin 56. The rear end of the second link 52 is rotatably connected to the upper end of the lever 53 via a horizontal pin 57. Further, a positioning member 58 made of a bolt and a nut is attached so as to penetrate the first link 51 in the vertical direction, and a lower end of the positioning member 58 is
8A, the idea C of the link mechanism 50 is obtained.
The operation to the lower side (one side) is restricted within the limit. The lever 53 is fixed to the other end of the valve stem 3, and the lower end of the lever 53 is connected to the hydraulic cylinder 7 via a horizontal pin 59.
Are connected to each other. Further, a projection 53A is protruded from the lower end of the lever 53, and an opening pointer 53B is provided behind the projection 53A. The hydraulic cylinder 7 is connected to a cylinder base 5 through a horizontal trunnion 8 as shown in FIG.
The cylinder base 5 is swingably supported by a trunnion cover 5A which removably closes one opening of the cylinder base 5. In FIG. 4, reference numeral 17 denotes an upper stopper, and reference numeral 18 denotes a lower stopper, each of which is provided corresponding to the vicinity of the balance weight 14 in the sensor lever 14. In FIG. 7, 9A and 9B are limit switches, 9C is an opening scale plate, and 9D is a stopper. The opening scale plate 9C is provided corresponding to the rotation path R, and the opening scale plate 9C is provided corresponding to the opening indicator 53B.

In the emergency shutoff valve configured as described above, in the region where the flow velocity of the passing water flow F shown in FIG. 4 is less than the set value, the moment generated by the balance weight 15 of the flow velocity detecting mechanism 10 and the moment generated by the sensor weight 16 As a result, the sensor lever 14 is held in a downward-rightward position shown by the solid line in contact with the upper stopper 17, and the flow sensor 11 is at the position shown by the solid line. Accordingly, the latch lever 22 of the engagement / disengagement mechanism 20 is also held at the first position shown by the solid line, and the engagement claw 22d engages with the claw portion 31A of the latch 31 of the rotation mechanism 30, and the valve body 2 of FIG. The valve is held in a substantially horizontal posture with the valve open.

For example, when the downstream pipe 4B of the emergency shut-off valve is damaged due to the occurrence of an earthquake or the like and the flow rate of the passing water flow F shown in FIG. 4 exceeds a set value, the flow sensor 11 turns to the position shown by the phantom line. As a result, the sensor lever 14 is held in a posture of rising to the right in contact with the lower stopper 18 as shown by a virtual line. As a result, the rod 21 of the engagement / disengagement mechanism 20 is pulled up, and the latch lever 22 is rotated clockwise to the second position indicated by the imaginary line, so that the engagement claw 22 d is rotated.
0 is retracted from the claw 31A of the latch 31. Engagement claw 22d of latch lever 22 and claw 31 of latch 31
When the engagement with A is released, the lever 35 and the shaft 34 (see FIG. 8) are indicated by phantom lines due to the weight of the weight 32 of the rotating mechanism 30 held at the position shown by the solid line in FIG. While rotating to the position shown, the striker 33 also rotates from the position shown by the broken line to the position shown by the virtual line.

[0009] By rotating the striker 33, FIG.
The striking pin 33B shown in (1) collides with the lower surface of the joint portion between the rear end of the first link 51 and the front end of the second link 52 in the link mechanism 50 and pushes up. As a result, the pin 56 moves to the upper side (the other side) beyond the thought point C1 of the link mechanism 50. At that moment, the lever 41 and the valve rod 3 are rotated in the direction of arrow R1 by the closing torque of the weight 42 of the torque generating source 40 shown in FIG. When the valve element 2 starts to rotate in the valve closing direction, the dynamic pressure of the passing water flow W is applied to the valve element 2 to generate hydraulic torque in the valve closing direction. On the other hand, lever-5
7 is in a state prior to being rotated by the weight of the weight 42, that is, in a position shown by a solid line in FIG. 7, and in a state where the protrusion 53A is in contact with the limit switch 9A, the high-pressure oil in the front chamber of the hydraulic cylinder 7 is Is returned to an oil tank (not shown) through a return passage (not shown). Therefore, by the rotation of the lever 53, the piston rod 7A of the hydraulic cylinder 7 moves forward and the hydraulic cylinder 7
7 tilts upward (upward) in FIG. 7 around the trunnion shaft 8 in FIG. By operating the hydraulic cylinder 7, the closing torque of the weight 42 by its own weight and the closing speed of the valve body 2 in FIG. 3 by the hydraulic torque by the dynamic pressure of the passing water flow W are adjusted to reduce the water hammer phenomenon. While preventing the occurrence, the valve body 2 is closed in a substantially vertical posture to shut off the flow of water from the upstream pipe 4A to the downstream pipe 4B. This closed state of the valve together with the valve rod 3
Are held by rotating from the position shown by the solid line in FIG. 9 to the position shown by the imaginary line abutting on the stopper 9D. When the lever 53 pivots to the position indicated by the imaginary line in contact with the stopper 9D and stops, the projection 53A contacts the limit switch 9B, and the high-pressure oil in the rear chamber of the hydraulic cylinder 7 returns to the return passage. It is returned to an oil tank (not shown) through (not shown).

As described above, the conventional emergency shutoff valve can automatically shut off water flow in an emergency when the pipe 4B is damaged by an earthquake. On the other hand, the rotation start flow rate for rotating the flow sensor 11 toward the position shown by the imaginary line in FIG. 4 is based on the balance between the moment generated by the balance weight 15 of the flow rate detection mechanism 10 and the moment generated by the sensor weight 16. It can be set. That is, the rotation start flow velocity of the flow sensor 11 is set by the weight ratio of the balance weight 15 and the sensor weight 16 and the lever ratio, and the rotation start flow velocity of the flow sensor 11 is set by changing the lever ratio. It is configured so that the value can be changed step by step.

[0011]

However, in the conventional flow velocity detecting mechanism, the rotation start flow velocity of the flow sensor 11 is set only by the balance of the moment.
When an external factor such as severe pitching or rolling or contact of other members is applied to the sensor 14, the sensor lever 14 revolves involuntarily despite the region where the flow velocity of the passing water flow F is less than the set value. As a result, it is possible to assume that a malfunction that the valve body 2 is closed and the water flow is automatically cut off is generated. Therefore, the present invention avoids the immediate movement of the sensor lever even if external factors such as severe pitching or rolling and contact of other members are applied to the sensor lever, and the malfunction of the sensor lever caused by unintended rotation occurs. It is an object of the present invention to provide a flow velocity detecting mechanism capable of reliably preventing the flow rate.

[0012]

In order to achieve the above-mentioned object, a flow rate detecting mechanism according to the present invention comprises a vertical flow sensor which projects inside a fluid passage and interferes with a passing fluid, and a flow sensor having the same structure. A lateral sensor shaft fixed to the base end of the sensor and rotatably supported, a lateral sensor lever intersecting the sensor axis and having a fulcrum fixed thereto, and the fulcrum of the sensor lever A balance weight fixed to one side of the support portion, and a sensor weight positioned on the other side of the fulcrum portion so as to be slidable and positionable, wherein the flow velocity of the water flow in the passage is less than a set value. In the above, the flow sensor and the sensor lever are held at predetermined positions by a balance between a moment generated by the balance weight and a moment generated by the sensor weight. In a flow rate detecting mechanism of an emergency shut-off valve configured to rotate the flow sensor and the sensor lever together with the sensor axis about the sensor axis when the flow rate of the passing water flow becomes equal to or more than a set value, the sensor lever A damper is provided to buffer the external factor that is loaded for a short time to prevent the rotation of the sensor lever and to allow the rotation of the flow sensor and the sensor lever only by the continuation of the flow velocity equal to or higher than the set value. It is characterized by having.

According to the present invention, even if an external factor such as severe pitching or rolling or contact of other members is applied to the sensor lever for a short time, the sensor lever is prevented from immediately moving by the damping action of the damper, and the sensor lever is prevented from moving immediately. It is possible to reliably prevent the occurrence of a malfunction due to the undesired rotation. Also, when an abnormal situation occurs in which the flow velocity exceeds the set value,
By rotating the flow sensor and the sensor lever, the valve body is closed, and the water flow can be automatically shut off.

[0014]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a side view showing an embodiment of the present invention, and FIG. 2 is an enlarged sectional view of a main part. The same or corresponding parts as those of the conventional emergency shutoff valve and the flow velocity detecting mechanism are denoted by the same reference numerals. 1 and 2, a flow rate detecting mechanism 10 includes a flow sensor 11 protruding into a valve box 1, a sensor shaft 13 horizontally and rotatably supported in a hood 12, and an outside of a hood 12. Sensor axis 1
The sensor lever 14 has a fulcrum fixed to one end of the sensor lever 3 and a balance weight 15 fixed to one end of a fulcrum 14A of the sensor lever 14.
The base end of 1 is fixed to the sensor shaft 13.

The engagement / disengagement mechanism 20 includes a vertical rod 21
And a bell-crank-shaped latch lever 22 connected to and linked to the lower end of the rod 21. Rod 2
The upper end of the sensor lever 1 is pivotally movable via a pin 23.
The lower end of the latch lever 22 is connected to the distal end of the one-side extension 22A of the latch lever 22. The latch lever 22 is rotatably supported by the pin 22B, and is provided with an engaging claw 22d at the distal end of the other side extension 22D.

On the other hand, the lower end of the hood 12 and the sensor lever
A damper 70 is provided between the fulcrum 14A and the balance weight 15 in FIG. This damper 70
Is provided to buffer the external factor applied to the sensor lever 14 for a short time to prevent the rotation of the sensor lever 14, and to allow the rotation of the flow sensor 11 and the sensor lever 14 only by the continuation of the flow velocity equal to or higher than the set value. A main body 71 having a cylindrical shape, a piston 72 accommodated in the main body 71 movably in the axial direction, and a lower end connected to the piston 72 so as to be movable forward and backward and in a liquid-tight manner. The main body 71 has a damper oil 74 sealed therein, and the piston 72 has an orifice 72a penetrating in the axial direction. The lower end of the main body 71 is rotatably supported by the lower end of the hood 12 via a pin 75, and the upper end of the rod 73 is connected to the fulcrum 14A of the sensor lever 14 and the balance weight 15 via a pin 76. It is rotatably connected between them.

With such a configuration, the downstream pipe 4B of the emergency shutoff valve is damaged due to, for example, the occurrence of an earthquake, and the flow rate of the passing water flow F becomes equal to or higher than the set value. The flow sensor 11 rotates to the position shown by the imaginary line in FIG. 1, and the sensor lever 14 is held in the posture of rising to the right as shown by the imaginary line. . As a result, the rod 21 of the engagement / disengagement mechanism 20 is pulled up, and the latch lever 22 is rotated clockwise to the second position indicated by the imaginary line, and the engagement claw 22d is latched by the latch 31 of the rotation mechanism 30.
From the claw portion 31A. When the engagement between the engagement claw 22d of the latch lever 22 and the claw portion 31A of the latch 31 is released, the valve body 2 of FIG. Can be shut off.

On the other hand, even if the sensor lever 14 is subjected to a short-term external load such as severe pitching or rolling, or contact with other members, the damper 70 prevents the sensor lever 14 from moving immediately, and the damper 70 prevents the sensor lever 14 from immediately moving. It is possible to reliably prevent the occurrence of a malfunction due to the undesired rotation.

[0019]

As described above, according to the present invention, the external force applied to the sensor lever for a short time is buffered to prevent the rotation of the sensor lever, and the flow sensor is controlled only by the continuation of the flow velocity exceeding the set value. Also, since a damper that allows the rotation of the sensor lever is provided, even if an external factor such as severe pitching or rolling or contact of other members is applied to the sensor lever for a short time, the damper dampers the sensor lever so that the sensor lever can be rotated. Immediate movement can be avoided, and malfunction due to unintentional rotation of the sensor lever can be reliably prevented. Also, when an abnormal situation occurs in which the flow velocity exceeds the set value, the flow
By rotating the sensor and the sensor lever, the valve body can be closed and the water flow can be automatically shut off.

[Brief description of the drawings]

FIG. 1 is a side view showing an embodiment of the present invention.

FIG. 2 is an enlarged sectional view of a main part.

FIG. 3 is a perspective view showing an example of an emergency shutoff valve.

FIG. 4 is an enlarged longitudinal side view showing a relationship between a flow velocity detection mechanism, an engagement / disengagement mechanism, and a rotation mechanism.

FIG. 5 is a sectional view taken along line AA of FIG. 4;

FIG. 6 is a sectional view taken along line BB of FIG. 4;

FIG. 7 is an enlarged side view showing the relationship between the rotation mechanism and the link mechanism.

FIG. 8 is a sectional view taken along line CC of FIG. 7;

FIG. 9 is a longitudinal sectional side view showing the link mechanism in an enlarged manner.

FIG. 10 is a sectional view taken along line DD in FIG. 9;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Valve box (fluid passage) 4A piping (fluid passage) 4B piping (fluid passage) 10 Flow velocity detecting mechanism 11 Flow sensor 13 Sensor shaft 14 Sensor lever 14A Support point 15 Balance weight 16 Sensor weight 70 Damper F Passing water flow (passing fluid)

Claims (1)

[Claims] 1. A flow sensor in a vertical direction which projects inside a fluid passage and interferes with a passing fluid, and a lateral sensor which is rotatably supported by fixing a base end of the flow sensor. A shaft, a lateral sensor lever intersecting the sensor axis and having a fulcrum secured thereto, a balance weight secured to one side of the fulcrum in the sensor lever, and a balance weight secured to the other side of the fulcrum. A sensor weight mounted so as to be slidable and positionable, and in a region where the flow rate of the water flowing through the passage is less than a set value, the moment generated by the balance weight and the moment generated by the sensor weight are balanced. Holding the sensor and the sensor lever at predetermined positions, and when the flow velocity of the water flow passing through the passage becomes equal to or higher than a set value, the sensor shaft is rotated around the rotation axis; In the flow rate detecting mechanism of the emergency shut-off valve configured to rotate the flow sensor and the sensor lever together with the support shaft, an external factor applied to the sensor lever for a short time is buffered to prevent the rotation of the sensor lever. And a damper for allowing the flow sensor and the sensor lever to rotate only when the flow velocity is equal to or higher than the set value.