JPH09242894A - Ball valve for gas conduit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a ball valve for a gas conduit which requires a small installation pit and is easy in the selection of an installation place. SOLUTION: This ball valve for a gas conduit is equipped with a valve body 20 insertedly provided between gas conduits 4a, 4b and a valve body 22 which is provided with a through hole 25 and accommodated in the valve body 20, and is composed to control the shutting off and conducting of gas flow. In this case, the ball valve is provided with the first pressure lead means 33 opened to the through hole 25; the second pressure lead means 35 opened to the upstream side part 4a of the gas conduit; and a pressure difference/flow rate converting means 38 which is additionally provided in the valve body 20 and obtains physical quantity responding to gas flow rate on a difference between both pressures given from the first and the second pressure lead means, and the through hole 25 is axially symmetry, and at least a diameter in an end part on the side of the opening part of the second pressure lead means coincides with the diameter D of the gas conduit, and a sectional area from the above end part to the opening part of the first pressure lead means decreases monotonously, and its decrease rate also becomes smaller in a monotone.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ball valve used as a gas shutoff valve or a flow rate adjusting valve on a conduit of a gas supply conduit, and more specifically, a valve having a flow rate detecting means built in a valve body. The present invention relates to a ball valve capable of simultaneously measuring a gas flow rate in addition to its original function.

[0002]

2. Description of the Related Art A general gas supply system, as shown in FIG. 3, is a gas produced in a factory 1 (pressure = 10 kgf /
cm ² (1 MPa or more) is sent to the governor station 3 via the high pressure conduit 2, and the gas depressurized by the governor station 3 (pressure = less than 10 kg / cm ² (1 MPa) to 1 kg / cm ² (0.1 MPa)). Above) is medium pressure conduit 4
Gas delivered to the district governor 5 in each consumption area via the gas and further depressurized in the district governor 5 (1 kg / cm
² (less than 0.1 MPa) is supplied to each consumer 7 via the low pressure conduit 6.

Such a gas supply system can cut off the supply of gas based on a command from the central monitoring center 8 as a countermeasure against a disaster such as an earthquake. That is, the high-pressure conduit 2 is provided with the emergency cutoff valve 10 so that the gas sent from the factory 1 can be cut off. Further, a regional block valve 11 (shutoff valve) is provided in the medium-pressure conduit 4 reaching the district governor 5 in each consumption area, so that the gas can be shut off there as well.
Since the regional block valves 11 are separately provided in front of the district governor 5 separated from the governor station 3 for each consumption area, the number of the regional block valves 11 installed is more than 5000.

In addition to the above-described gas shutoff function, the gas supply system measures the flow rate of the gas in order to monitor whether or not the supply gas is stably supplied to each downstream consumption area. The function to do is also provided. for that reason,
In the installation pit (recess, hole) 12 in which the regional block valve 11 is installed, as shown in FIG. 4, it is usually hot to take out the gas for flow rate measurement from the pipe in which the regional block valve 11 is inserted. A tapping 13 and a gas pressure gauge 14 are provided side by side. These are arranged near the regional block valve 11 in the same pipeline.

On the hot tapping 13, as seen in a known gas flow meter (see, for example, Japanese Patent Application Laid-Open No. 4-2922), a flow rate detecting sensor 15 is hung in the conduit of the intermediate pressure conduit 4, and this sensor is provided. Flow rate measurement in which the static pressure and the dynamic pressure of the gas obtained by 15 are introduced to the differential pressure / flow rate converter 18 on the ground via the pressure guiding pipes 16 and 17 so that the flow rate of the gas can be calculated from the differential pressure of the two. Means are provided. If steam or tar in the gas adheres to the flow rate detection sensor 15, an error occurs. Therefore, in order to make maintenance work such as cleaning and replacement possible / easy, the hot tapping 13 is provided with a gas outlet. An opening / closing valve 19 is inserted in the passage, and a space 20 for maintenance and inspection is formed above the valve position. And this space part 20
The hot tapping 13 is installed so that the flow rate detection sensor 15 can be pulled inside the chamber to perform maintenance work.
Has a relatively long shape in the vertical direction.

The flow rate detecting sensor 15 has a gas conduit arranged in a straight pipe portion having a length 10 times or more the diameter. To calculate the flow rate by measuring the flow velocity at a certain point in the pipeline, it is necessary to know the flow velocity distribution in the pipeline cross section, and to stabilize the flow velocity distribution in a known pattern, the gas flow must be in a laminar state. Alternatively, it is necessary to make a developed turbulent state, and for that purpose, a straight pipe portion of a predetermined length is required.

If the required straight pipe section cannot be obtained,
A volumetric flow meter or a correlation flow meter may be used as the flow rate detection sensor. This is because the volumetric flow meter can detect the flow rate without depending on the flow velocity distribution, and the correlation flow meter can suppress fluctuations due to changes in the flow velocity distribution by combining a plurality of flow meters. However, the volumetric flowmeter has drawbacks such as slow response speed, large pressure loss, and difficulty in incorporation into an existing pipeline.
There are drawbacks such as complexity, and all are used only in a limited way.

[0008]

As described above, when a conventional ball valve for a gas conduit is used, in many cases, in addition to the ball valve, a flow rate detection sensor and the like are provided side by side in the same pit, The installation place is limited to the straight pipe part of a predetermined length.

However, if a plurality of pieces of equipment are installed side by side in the same pit, the pit must be enlarged. For this reason, not only the construction cost for pit construction increases, but also the installation location is restricted. Especially, the installation cost of a large number of regional block valves will be enormous because of the huge construction cost.

In the case of a gas conduit, the length is 10 diameters.
There are almost no straight pipe sections that are more than double the length. For this reason, the installation place is limited, or even the installation place does not exist, which makes it difficult to select the installation place.

The present invention has been made in view of the above unsolved problems, and an object of the present invention is to provide a ball valve for a gas conduit having a small installation pit and relatively easy installation site selection.

[0012]

A ball valve for a gas conduit, which was invented in order to solve the above-mentioned problems, will be described below in terms of its structure and operational effects.

[First Solving Means] A ball valve for a gas conduit according to the first solving means (as described in claim 1 at the beginning of the application) includes a valve main body inserted in the gas conduit and a gas circulating member. A spherical valve body having a through hole formed therein and housed in the valve body, the ball valve for a gas conduit controlling the interruption or conduction of the gas flow in the gas conduit by rotating the valve body. A first pressure guide means provided on the inner side surface of the through hole, a second pressure guide means provided on the inner side surface of the upstream side portion of the gas conduit, and a valve body. And a differential pressure / flow rate conversion means for obtaining a physical quantity according to a gas flow rate in the gas conduit based on a difference between both pressures from the first and second pressure guiding means, and the through hole, Is axially symmetric and is located at least on the opening side of the second pressure guiding means. The diameter of the end matches the diameter of the gas conduit, and at least the cross-sectional area from this end to the opening of the first pressure guiding means monotonically decreases and the rate of decrease monotonically decreases. It is characterized by being formed.

In the ball valve for the gas conduit of the first means, the through hole of the valve body is narrowed from the end to the center, so that the gas flow from the gas conduit is accelerated. The lateral pressure drops at the center of the through hole. And
The gas flow rate is detected by the differential pressure / flow rate conversion means attached to the valve body based on the difference between the high pressure in the gas conduit and the low pressure in the through hole. Thus, the differential pressure /
By integrally incorporating the flow rate detecting means such as the flow rate converting means into the ball valve, it is not necessary to separately install the flow rate detecting sensor or the like in the ball valve installation pit for the gas conduit. Therefore, the installation pit can be reduced by that amount.

Further, since the diameter of the end of the through hole is made to match the diameter of the gas conduit and the through hole is formed in a specific shape,
Regarding the stability of the flow velocity distribution pattern required for estimation and calculation of the flow velocity, the through hole portion also works as a part of the straight pipe portion of the gas conduit. As a result, the selection condition for the straight pipe portion having the predetermined length necessary for installing the ball valve is relaxed.

Further, since the through hole is gradually narrowed from the end portion to the center, even if the gas flow is accelerated to a considerably high speed, the streamline is unlikely to separate from the side surface. As a result, the gas flow rate can be accurately measured over a wide flow velocity range.

Therefore, according to the present invention, a ball valve for a gas conduit having a small installation pit and having a relatively easy selection of an installation site can accurately measure the gas flow rate over a wide flow velocity range. A ball valve can be realized.

As a result, the construction cost required to install the regional block valve can be considerably reduced as compared with the conventional construction. Further, for the gas supply system downstream of the installed ball valve, the gas can be shut off and the flow rate can be measured for each system, which facilitates the formation of a conduit network in the gas supply system. Further, it becomes possible to easily manage the stable gas supply and the safety management for each consumer.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION A specific mode for carrying out the ball valve for a gas conduit according to the first solving means will be described below in terms of its structure and operation and effect.

[Second Solution] The ball valve for the gas conduit of the second solution (as described in claim 2 at the beginning of the application) has the ball for the gas conduit of the first solution described above. A third pressure-introducing means provided on an inner surface of a downstream portion of the gas conduit, the differential pressure /
The flow rate conversion means obtains the physical quantity based on the difference between the higher pressure of the pressures from the second and third pressure guiding means and the pressure from the first pressure guiding means. The through-hole is characterized in that the shape of the upstream side portion and the shape of the downstream side portion are plane-symmetrical with respect to the central cross section as a reference plane.

In the ball valve for the gas conduit according to the second means, the gas pressure in the upstream is generally higher than that in the downstream if the gas flows from upstream to downstream in a natural direction. Therefore, the action and effect of the above-described first solving means are exhibited. On the other hand, if the gas flows in the opposite direction due to some cause such as gas leakage,
The downstream side is replaced with the original one, and the pressure from the third pressure guiding means becomes higher than the pressure from the second pressure guiding means. The differential pressure / flow rate conversion means detects the flow rate based on the difference between the two pressures from the first and third pressure guiding means.

Here, since the through holes are symmetrical on the upstream side and the downstream side, the pressure from the second pressure guiding means for the gas flow in the original direction and the gas in the opposite direction. The pressure from the third pressure guiding means with respect to the flow shows almost the same characteristics. Accordingly, the flow rate is detected based on the difference between both pressures from the first and second pressure guiding means and the difference between both pressures from the first and third pressure guiding means with respect to the gas flow in the opposite direction. Even when performing, the required physical quantity can be obtained using the same coefficient, processing, and circuit.

Therefore, according to the present invention, in addition to the above-described effects such as a small installation pit, a ball valve for a gas conduit capable of measuring a gas flow rate in both forward and reverse directions with a simple circuit or the like can be realized. You can

[Third Solving Means] A ball valve for a gas conduit of the third solving means (as described in claim 3 at the beginning of the application) is the gas conduit of the first or second solving means described above. The through-hole has a quadratic curve (preferably a minor axis of 1 / major axis) in a longitudinal section passing through the central axis of the hole.
5 is an ellipse).

In the ball valve for gas conduit according to the third means, the longitudinal shape is adapted to the quadratic curve, so that the NC machine is directly instructed the machining shape. It becomes possible to do. Therefore, even a curved surface can be easily and accurately processed.

Further, in the case of the above elliptical shape, this shape is particularly matched with the smooth streamline change, so that the gas pressure loss due to passage through the through hole is extremely small. As a result, it is possible to overcome the drawbacks of the differential pressure flow type detection method.

Therefore, according to the present invention, it is possible to realize a ball valve for a gas conduit which is easy to manufacture and has a small pressure loss, in addition to the above-described effects such as a small installation pit.

[Fourth Solving Means] The ball valve for the gas conduit of the fourth solving means (as described in claim 4 at the beginning of the application) is the gas conduit of the above-mentioned first to third solving means. A ball valve for a vehicle, wherein the differential pressure / flow rate conversion means is provided above or above the valve body,
The pressure guiding means is a hollow passage formed at least in the upper portion of the valve body along a vertical line passing through the center of the valve body.

In the ball valve for gas conduit according to the fourth means, the pressure in the through hole is detected through the hollow passage, which passes through the center of the valve body. Since it is formed by making a hole in the upper portion of the valve body along the vertical line, it opens at approximately the center of the through hole. Here, the change in the cross-section of the through hole and thus in the gas flow velocity is smaller in the central portion than in the end portions. Therefore, even if the position where the hollow passage is pierced with respect to the through hole varies to some extent, the pressure from the first pressure guiding means is hardly affected by this. This makes the ball valve for the gas conduit easy to manufacture.

Further, since the differential pressure / flow rate converting means is also provided above, the first pressure guiding means can be embodied without providing piping or the like on the outer surface or the outside of the valve body. This allows
Even with the integrated structure of the ball valve and the flow rate detecting means, it can be made simple and compact.

Therefore, according to the present invention, in addition to the above-described effects such as a small installation pit, a ball valve for a gas conduit which is easy to manufacture and compact can be realized.

[Fifth Solving Means] The ball valve for gas conduit of the fifth solving means (as described in claim 5 at the beginning of the application) is the gas conduit of the above-mentioned first to fourth solving means. Ball valve for use, which is provided so as to protrude from the valve body (on either or both of the upstream side and the downstream side of the gas conduit), and (at least when the gas flow is controlled to be in a conducting state). A connecting pipe portion communicating with the through hole, having a diameter matching the diameter of the gas conduit, and having one end connectable to the gas conduit; At least one of the pressure guiding means of
It is characterized in that it is opened on the inner side surface of the connecting pipe portion instead of the gas conduit.

In the ball valve for the gas conduit according to the fifth solving means, the connecting pipe portion has the same action as the gas conduit in measuring the gas flow rate. Moreover, the second
Since the pressure-inducing means 3 is provided so as to open in the connecting pipe portion, even if the ball valve is not connected to the gas conduit,
It is possible to carry out the piping work for the pressure guiding means 3 in advance. This can reduce cramped construction work in the pit at the site.

Therefore, according to the present invention, it is possible to realize a ball valve for a gas conduit which is easy to install, in addition to the above-described effects such as a small installation pit.

[Sixth Solution] The ball valve for gas conduit of the sixth solution (as described in claim 6 at the beginning of the application) is the gas conduit of the above-mentioned first to fifth solutions. A ball valve for use, wherein the distance between the opening portion of the second pressure guiding means or the second and third pressure guiding means and the corresponding end of the through hole is 90% or more of the diameter of the gas conduit. Is characterized in that.

In the ball valve for gas conduit according to the sixth means, the opening position for detecting the high pressure side pressure in the gas conduit is sufficiently separated from the through hole. As a result, when the pressure on the high-pressure side in the gas conduit is detected, the throttling shape of the through-hole hardly affects the flow velocity distribution undesirably.

Therefore, according to the present invention, it is possible to realize a ball valve for a gas conduit which can accurately measure the gas flow rate in addition to the above-described effects such as a small installation pit.

[0038]

Embodiments of the ball valve for a gas conduit according to the present invention will be described in detail with reference to the drawings.
FIG. 1 is an overall view thereof. FIG. 2 is a block diagram of the differential pressure / flow rate converter.

This ball valve is provided with a valve body 20 having a connection port for the intermediate pressure conduit 4a on the upstream side and a medium pressure conduit 4b on the downstream side, and a spherical valve body 22. The valve body 22 includes a valve body 2 as is found in a normal ball valve.
It is decorated with 0. The upper and lower sides thereof are connected to the upper stem shaft 24 and the lower stem shaft 23, and are supported by the valve main body 20 via these and are bidirectionally rotatable.

Further, a through hole 25 is bored in the valve body 22, and when the through hole 25 is located in the same direction as the axis of the intermediate pressure conduits 4a, 4b, the valve is in the open position and the through hole 25
The valve is in the closed position in a state in which is positioned at a right angle to the axes of the medium pressure conduits 4a and 4b. This makes this ball valve
Rotating the valve body 22 to block the gas flow in the gas conduit /
It controls the continuity.

The through hole 25 is rotationally symmetrical with respect to the central axis of the hole, and is machined so that the shape of the longitudinal section passing through the axis is elliptical. In this ellipse, the minor axis is ⅕ of the major axis. Further, the through-hole 25 has an elliptical shape over the entire range so that the through-hole 25 is symmetrical with respect to the central cross-section as a reference plane, that is, the shape of the upstream portion and the shape of the downstream portion are plane-symmetrical. Processed. And
Both ends thereof have the same diameter as the diameter (D) of the gas conduit. As a result, in the through hole 25, the cross-sectional area from the end portion to the central portion monotonously decreases, and the reduction rate also monotonically decreases.

On the upper part of the valve body 20, flanges 26, 2 are provided.
A gear box 28 is connected via 7, and one end of the upper stem shaft 24 projects into and is supported in the gear box 28. A pinion gear 32 is fixed to one end of the upper stem shaft 24, and the pinion gear 32 is connected to the gear box 28.
It meshes with a worm gear (not shown). The worm gear is connected to the geared motor 30 attached to the gear box 28 and the rotating shaft of the handle 31. The valve body 22 is rotationally driven via the pinion gear 32 or the like and the upper stem shaft 24 by the rotation operation of the geared motor 30 or the handle 31.

Further, a differential pressure / flow rate converter 38, which will be described later, is mounted on the upper part thereof. A hollow passage 33 is bored in the shaft center of the upper stem shaft 24. A lower side of the hollow passage 33 extends to the through hole 25 through the valve body 22 to open to an inner surface of the through hole 25, and an upper side of the hollow passage 33 extends to the differential pressure / flow rate converter 38. As a result, this ball valve is provided with a hollow passage bored in the upper portion of the valve body along the vertical line passing through the center of the valve body as the first pressure guiding means.

A pressure guiding thin tube 35 is interposed as a second pressure guiding means between the intermediate pressure pipe 4a on the upstream side and the differential pressure / flow rate converter 38. Pressure conduit 4a
Is connected to the pressure extraction hole 34 opened on the inner surface of the. Further, the pressure take-out hole 34 is located at the end of the corresponding through-hole 25, that is, the end on the right side in the drawing, which is closer to the diameter 9 of the gas conduit.
It is provided at a place separated by a distance (0.9D) or more.

A pressure guiding thin tube 37 is provided as a third pressure guiding means between the intermediate pressure conduit 4b on the downstream side and the differential pressure / flow rate converter 38. Pressure conduit 4b
Is connected to a pressure take-out hole 36 opened on the inner side surface. Further, the pressure take-out hole 36 has a diameter of the gas conduit from the corresponding end of the through-hole 25, that is, the end on the left side in the figure, which is closer to the end, than the diameter of the gas conduit.
It is provided at a place separated by a distance (0.9D) or more.

The differential pressure / flow rate converter 38 shown in FIG.
Is a first differential pressure gauge for detecting the difference between the pressure from the hollow passage 33 and the pressure from the pressure guiding thin tube 35, and a second differential pressure gauge for detecting the difference between the pressure from the hollow passage 33 and the pressure from the pressure guiding thin tube 37. It is composed of a differential pressure gauge and a circuit such as a comparator that generates an electric signal having the larger value of these differential pressures and sends the electric signal to a signal processing unit or the like via a connection line 39.
This causes the differential pressure / flow rate converter 38 to indirectly
And a physical quantity corresponding to the gas flow rate in the gas conduit, based on the difference between the higher pressure of the pressures from the third pressure guiding means and the pressure from the first pressure guiding means. Has become.

In the differential pressure / flow rate converter shown in FIG. 2B, the differential pressure is detected by selecting either of the pressure guiding thin tubes 35 and 37 by the solenoid valve and then detecting the differential pressure. This is another configuration example in which only one is provided. Further, the differential pressure / flow rate converter shown in FIG. 2C is an example in which the pressure guiding thin tubes 35 and 37 are easily selected by a shuttle valve. These directly select the higher pressure of the pressures from the second and third pressure guiding means, and based on the difference between these pressures and the pressure from the first pressure guiding means. The physical quantity is obtained according to the gas flow rate in the gas conduit.

With respect to the ball valve for the gas conduit of this embodiment, its specific usage and operation will be described.

This ball valve is installed in the installation pit 12 in place of the conventional regional block valve (11) for the medium pressure conduit (4) buried in the soil. That is, in order to insert the valve body 20 between the intermediate pressure conduit 4a on the upstream side and the intermediate pressure conduit 4b on the downstream side that traverses the inside of the installation pit 12, the base 21 is placed on the bottom of the pit 12. The valve body 20 is placed on the valve body 20 and connected so that the upstream side and the downstream side of the intermediate pressure conduits 4a and 4b communicate with each other.

The gas is the medium pressure conduit 4a and the through hole 2.
5. When flowing through the medium pressure conduit 4b, the gas pressure becomes higher or lower in order of the medium pressure conduit 4a, the medium pressure conduit 4b, and the through hole 25 according to the flow velocity and the like. According to this, the pressure from each is also the pressure-conducting thin tube
5, the pressure guiding tube 37, and the hollow passage 33 in this order. Therefore,
The differential pressure / flow rate converter 38 detects the difference between the pressure of the pressure guiding thin tube 35 and the pressure of the hollow passage 33 as an electric signal.

On the other hand, when the gas flows in the reverse direction in the order of the intermediate pressure conduit 4b, the through hole 25, and the intermediate pressure conduit 4a, the gas pressure becomes the intermediate pressure conduit 4b, the intermediate pressure conduit 4a, and the through hole 25 in that order.
The pressure guiding is also in the order of the pressure guiding thin tube 37, the pressure guiding thin tube 35, and the hollow passage 33. Therefore, the differential pressure / flow rate converter 38 detects the difference between the pressure in the pressure guiding thin tube 37 and the pressure in the hollow passage 33 as an electric signal.

In any case, the electric signal is subjected to a predetermined calculation based on an empirical formula or the like in a signal processing unit or the like to obtain a gas flow rate value. This is displayed on the display unit (not shown). Alternatively, it may be sent to the central monitoring center 8 or the like in FIG.

Thus, by using the ball valve for this gas conduit, in addition to controlling the flow / interruption of the gas flow,
The gas flow rate in the gas conduit can be measured.

[0054]

As is apparent from the above description, in the ball valve for gas conduit according to the first solution means, the shape of the through hole formed in the valve body is devised so that the flow rate detecting means is used as the ball valve. It is a ball valve for a gas conduit that has a small installation pit and is relatively easy to select the installation site by being integrated into the ball valve, and can accurately measure the gas flow rate over a wide flow velocity range. Could be realized.

Further, in the ball valve for gas conduit of the second solving means, the through holes and the like are symmetrical on the upstream side / downstream side, so that the gas flow rate in both forward and reverse directions can be simplified. Now you can measure.

Furthermore, in the ball valve for gas conduit of the third solution means, the through-hole shape is adjusted to a suitable processing shape of the NC processing machine or the like, or even a smooth streamline change is achieved. By doing so, it was possible to realize a ball valve for a gas conduit that is easy to manufacture and has a small pressure loss.

Further, in the ball valve for gas conduit of the fourth solving means, the pressure from the first pressure guiding means is hardly influenced by the opening position of the through hole. By adopting a structure that does not require external piping or the like, a ball valve for a gas conduit that is easy to manufacture and compact can be realized.

Further, in the ball valve for the gas conduit of the fifth solving means, the piping work for the second and third pressure guiding means can be completed in advance, so that We were able to realize a ball valve for a gas conduit that is easy to install.

In addition, in the ball valve for gas conduit of the sixth solution means, the gas flow rate can be accurately controlled by avoiding the undesired influence of the throttling shape of the through hole. It was possible to realize a ball valve for a gas conduit that can be measured at any time.

[Brief description of drawings]

FIG. 1 is an overall view of an embodiment of a ball valve for a gas conduit according to the present invention at the time of installation.

FIG. 2 is a block diagram of the differential pressure / flow rate converter.

FIG. 3 is a schematic diagram illustrating a gas supply system.

FIG. 4 is a schematic view showing an installation form of a conventional regional block valve.

[Explanation of symbols]

 1 Factory 2 High-pressure conduit (gas conduit) 3 Governor station 4 Medium-pressure conduit (gas conduit) 5 District governor 6 Low-pressure conduit (gas conduit) 7 Consumer 8 Central monitoring center 10 Emergency shutoff valve (ball valve for gas conduit) 11 Regional block valve (ball valve for gas conduit) 12 Pit 13 Hot tapping 14 Pressure gauge 15 Flow rate detection sensor 16, 17 Pressure guide tube 18 Differential pressure / flow rate converter 19 Valve 20 Valve body 21 Base 22 Valve body 23 Lower stem Shaft 24 Upper stem shaft 25 Through hole 26, 27 Flange 28 Gabox 30 Geared motor 31 Handle 32 Pinion gear 33 Hollow passage (first pressure guiding means) 34, 36 Pressure extraction hole 35, 37 Pressure guiding tube (second and third) Pressure guiding means) 38 Differential pressure / flow rate converter (differential pressure / flow rate converting means) 39 Connection line 4a Medium pressure conduit (gas conduction 4b Intermediate pressure conduit (downstream part of gas conduit)

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Manabu Iwabuchi 3-16-42 Kitakarasuyama, Setagaya-ku, Tokyo (72) Inventor Tatsuya Ichihara 2-12-19 Shibuya, Shibuya-ku, Tokyo Yamatake Hanuel Co., Ltd. (72 ) Inventor Shinji Kusunoki 1-1, Nikkocho, Fuchu-shi, Tokyo Inside Japan Steel Works (72) Inventor Yasunari Mukai 1-6-1 Hankoshi Minami, Aki-ku, Hiroshima City, Hiroshima Prefecture

Claims (6)

[Claims] 1. A valve main body inserted into a gas conduit, and a spherical valve body having a through hole for gas flow formed therein and housed in the valve main body. In a ball valve for a gas conduit for controlling interruption / conduction of a gas flow in a gas conduit, a first pressure guiding means provided on an inner side surface of the through hole and an inner portion of an upstream side portion of the gas conduit. Second pressure guiding means provided with an opening on the side surface;
And a differential pressure / flow rate conversion means that is attached to the valve body and obtains a physical quantity according to the gas flow rate in the gas conduit based on the difference between both pressures from the first and second pressure guiding means. Is an axially symmetric type, and the diameter of at least the end portion of the second pressure guiding means located on the opening side matches the diameter of the gas conduit, and at least from this end portion the first pressure guiding means. A ball valve for a gas conduit, characterized in that it is formed so that the cross-sectional area reaching the opening of the means monotonically decreases and the rate of decrease thereof also monotonically decreases. 2. A third pressure guiding means provided on the inner side surface of the downstream side portion of the gas conduit, the differential pressure / flow rate converting means comprising the second and third pressure guiding means. Of the pressure from the higher pressure and the pressure from the first pressure guiding means, the physical quantity is obtained based on the difference between the two pressures. The ball valve for a gas conduit according to claim 1, wherein the shape of the upstream side portion and the shape of the downstream side portion are plane-symmetrical. 3. The gas conduit according to claim 1, wherein the through-hole has a longitudinal cross section passing through the center axis of the hole along a quadratic curve such as an ellipse. Ball valve. 4. The differential pressure / flow rate conversion means is provided above or above the valve body, and the first pressure guiding means extends along a vertical line passing through the center of the valve body. The ball valve for a gas conduit according to any one of claims 1 to 3, wherein the ball valve is a hollow passage formed at least in an upper portion of the valve body. 5. A connecting pipe portion, which is provided so as to project from the valve body, communicates with the through hole, has a diameter that matches the diameter of the gas conduit, and has one end connectable to the gas conduit, At least one of the second pressure-inducing means and the third pressure-inducing means is an opening on the inner side surface of the connecting pipe portion instead of the gas conduit. Ball valve for conduit. 6. The distance between the opening portion of the second pressure guiding means or the second and third pressure guiding means and the corresponding end of the through hole is 90% or more of the diameter of the gas conduit. A ball valve for a gas conduit according to any one of claims 1 to 5, characterized in that: