JP2000283821A - Passage switching mechanism for gas measuring apparatus and gas meter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently open/close a valve at a good reactivity with even a few change of the gas flow rate in switching a gas passage according to the gas flow rate by opening/closing the valve driven by a vertical displacement of a diaphragm with the gas pressure difference change between the upstream and downstream of an apparatus for measuring the gas flow rate. SOLUTION: For opening/closing a valve port 27, the port 27 and a main valve 59 are disposed in a housing 1 so that the shifting direction of the main valve 59 is vertical, the same as the displacing direction of a diaphragm 51, and the top end of a second link lever of a link mechanism 61 connected to the main valve 59 through a support 77 and a first link lever is pivoted to the peripheral edge of a lower case 63b of a diaphragm case 63 mounted on a top barrel 5 part of a first chamber 13.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a mechanism for switching a gas flow path provided in a housing of a gas metering device,
The present invention relates to a gas meter having this mechanism.

[0002]

2. Description of the Related Art In a gas meter or a gas leak detection device used in a collective gas supply facility for LP gas, city gas, or the like, a gas flow rate is measured for displaying a gas consumption amount and for determining the presence or absence of a gas leak. If a sensor having a high measurement accuracy at a relatively high flow rate and a sensor having a high measurement accuracy at a relatively low flow rate are selectively used, the measurement accuracy can be improved in a wide range.

Therefore, conventionally, a portion where a low flow passage is branched and joined to a high flow passage is provided in the gas flow passage, and especially when the gas flow is small, the valve element of the high flow passage is provided. A technique useful for enabling the above-mentioned sensors to be used properly, that is, the gas leak detection device disclosed in Japanese Patent Application Laid-Open No. H8-270900, has been proposed. Are known.

In the gas leak detecting device disclosed in Japanese Patent Application Laid-Open No. 8-270900, the diaphragm is moved up and down by a change in the difference between the gas pressure acting on both sides of the diaphragm on the upstream side of the diaphragm and the gas pressure on the downstream side of the diaphragm. The vertical displacement of the diaphragm is converted into a linear reciprocating motion in the horizontal direction by a link mechanism, and the operating member connected to the center of the valve body is supported so as to be movable in the horizontal direction. By transmitting the linear reciprocating motion in the direction to the operating member, the valve body is driven to open and close with respect to the valve seat of the high flow passage.

However, in the above-described conventional configuration,
When the vertical displacement of the diaphragm is converted into a horizontal displacement by the link mechanism and transmitted to the valve body, sliding friction corresponding to the weight of the valve body is generated between the operating member and its supporting portion, and this sliding friction is reduced. Since the power transmitted from the diaphragm to the valve body is lost by the amount corresponding to the loss, the opening and closing drive of the valve body powered by the change in the difference between the gas pressure on the upstream side of the diaphragm and the gas pressure on the downstream side of the diaphragm There is room for improvement in terms of efficient transmission.

In this respect, the fluidic gas meter disclosed in Japanese Patent Application Laid-Open No. 7-324953 has a structure in which a valve is directly connected to a diaphragm and the valve is displaced up and down in the same manner as the diaphragm to open and close. This is advantageous because the vertical displacement can be transmitted to the valve body without loss.

[0007]

However, in the fluidic gas meter disclosed in Japanese Patent Application Laid-Open No. 7-324953, since the valve element is directly connected to the diaphragm, the weight of the valve element is directly applied to the diaphragm. Unless the gas flow rate changes such that a large difference occurs between the gas pressure on the upstream side of the diaphragm and the gas pressure on the downstream side of the diaphragm, the diaphragm cannot be vertically displaced to open and close the valve.

[0008] The present invention has been made in view of the above circumstances,
An object of the present invention is a gas metering device that measures a gas flow rate for use amount display and leak detection, and a diaphragm that is vertically displaced by a change in a difference between a gas pressure on an upstream side and a gas pressure on a downstream side of the diaphragm, Using a valve that opens and closes with the vertical displacement of the diaphragm as the power, when switching the gas flow path according to the gas flow rate, the valve element opens and closes efficiently and responsively even with a slight change in the gas flow rate. An object of the present invention is to provide a flow path switching mechanism of a gas metering device that can be operated, and a suitable gas meter using the flow path switching mechanism.

[0009] Claims 1 and 2 achieve the above object.
The invention described above relates to a channel switching mechanism of a gas metering device, and the invention described in claim 3 relates to a gas meter.

[0010]

According to a first aspect of the present invention, there is provided a flow rate switching mechanism for a gas metering device, comprising: A low flow passage which bypasses at least the predetermined portion and allows passage of gas at a maximum flow rate lower than the maximum flow rate of the high flow passage, in the middle of the gas flow path, Up and down direction of the diaphragm which receives the gas pressure in the high flow passage portion on the upstream side of the gas flow from the predetermined position in the passage for one side and receives the gas pressure in the low flow passage on the other surface. A valve switching mechanism of a gas metering device that drives the valve element to open and close according to the flow rate of gas flowing through the gas flow path by transmitting the displacement to the valve element via a link mechanism. The opening and closing direction of the valve is up and down. Are arranged so that the direction,
Of the housing that displaceably supports the diaphragm, a supporting member connected to the valve body is supported movably in the up and down direction at a housing portion displaced at least in the up and down direction from the diaphragm, and the link mechanism includes the link mechanism. It is interposed between the diaphragm and the support member, and has a link lever supported by the housing.

According to a second aspect of the present invention, there is provided a flow path switching mechanism for a gas metering apparatus according to the first aspect, wherein the housing portion is provided with the diaphragm. A guide shaft that is displaced in the horizontal direction from the center and extends vertically in the center of the diaphragm is connected to the guide hole of the guide member extending from the housing portion in the vertical direction. It is assumed to be movably inserted.

Further, a gas meter according to the present invention described in claim 3 is a gas meter having a flow path switching mechanism of the gas metering device according to claim 1 or 2, wherein the housing is divided in a vertical direction. Wherein the housing portion is provided in a housing body different from the housing body in which the predetermined portion of the high flow passage is formed.

According to the flow path switching mechanism of the gas metering device of the present invention, since the opening and closing direction of the predetermined portion of the high flow passage by the valve body is the same vertical direction as the displacement direction of the diaphragm. It is not necessary to change the direction of the displacement of the diaphragm transmitted to the valve body by the link mechanism in the middle.

In addition, the valve body is connected to a link lever supported by the housing of the link mechanism via a support member movably supported in the up-down direction at the housing, and the diaphragm and the valve body are directly connected. Since there is no valve body, the entire weight of the valve body is not directly applied to the diaphragm.

According to the second aspect of the present invention, the guide shaft connected to the center of the diaphragm and extending in the vertical direction moves the support member in the vertical direction. Since the diaphragm is vertically movably inserted into a guide hole of a guide member extending from a housing portion that supports the diaphragm, the displacement of the diaphragm in the vertical direction is guided by the guide shaft and the guide hole of the guide member. Will be.

In addition, since the housing portion is displaced in the horizontal direction from the center of the diaphragm, when the diaphragm is displaced in the vertical direction, the guide shaft does not interfere with the support member and the valve body.

Further, according to the gas meter of the present invention, the support member connected to the valve body is vertically attached to the housing body different from the housing body in which the predetermined portion of the high flow passage is formed. Since the housing portion that is movably supported is provided, as long as the housing members are not assembled, even after the valve body is assembled to the housing portion side via the support member, the predetermined portion of the high flow passage is It will be located on the other housing body side.

In addition, the housing constituting the housing is divided in the vertical direction, and the opening and closing direction of the valve element for opening and closing a predetermined portion of the high flow passage is also in the vertical direction. Unless the valve body is assembled on the housing location side, in a stage before assembling the housing bodies, a predetermined portion of the high flow passage, which is a valve seat opened and closed by the valve body, is a part of the housing body in which the predetermined location is formed. It will be exposed to the outside.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a flow path switching mechanism of a gas metering device according to the present invention will be described below with reference to the drawings together with a gas meter.

FIG. 1 is a front view showing a schematic structure of an electronic gas meter according to one embodiment of the present invention. The electronic gas meter (hereinafter abbreviated as “gas meter”) of the present embodiment is
A rectangular housing in a plan view indicated by reference numeral 1 in FIG. 1 and a flow path switching unit 55 housed in the housing 1
(See FIG. 2) is configured so that it can be vertically divided into three parts by a covered lid 3, a cylindrical body 5, and a bottomed bottom 7.

As shown in the longitudinal section of the housing 1 in FIG. 2, the lid 3 has a gas inlet 9 connected to a gas supply source (not shown) and a gas inlet 9 connected to a gas consumption source (not shown). A gas outlet 11 is formed.

The body 5 has a first chamber 13 communicating with the gas inlet 9 with the lid 3 attached to the upper end,
A second chamber 15 communicating with the gas outlet 11 with the lid 3 attached to the upper end is partitioned by a partition wall 17 and formed as shown in a plan view in FIG. And a third chamber 19 that is not in communication with any of the gas outlets 11 is formed by being partitioned by partitions 21 and 23.

As shown in FIG. 2, the second chamber 15 partially extends below the first chamber 13 by a partition wall 25 extending horizontally from the lower end of the partition wall 17. The valve chamber 27 communicates with the first chamber 13 via a corresponding valve port 27 (corresponding to a predetermined location), and a ring member 29 for adjusting the vertical position of the port is screwed into the valve port 27.

The first chamber 13 is provided with a measuring unit 31. Inside the measuring unit 31, as shown in FIG.
3 and a sub-flow path 35 whose upper end is open and the lower end is closed.

As shown in FIG. 2, the sub flow path 35 is connected to an inlet 37a of a cylindrical high flow rate flow rate detection sensor 37 composed of, for example, an ultrasonic sensor.
The outlet 37b of the flow rate detection sensor 37 for the high flow rate region is
The lower end of the weighing unit 31 is connected to a mounting piece portion 31a, and is open to the outside of the sub flow path 35.

As shown in FIG. 3, the third chamber 19 communicates with the sub-flow path 35 through a communication pipe 39 provided between the partition 21 and the measuring unit 31. Is connected to an inlet 43a of a cylindrical low flow rate flow rate detection sensor 43, such as an ultrasonic sensor, an IC flow sensor, or the like, which is attached through a mounting plate 41 to the low flow rate flow rate sensor. The outlet 43b of the detection sensor 43 is connected to the fourth chamber 4 formed between the partition wall 23 and the mounting plate 41.
The fourth chamber 45 and the second chamber 15 communicate with each other via a shutoff valve port 47 formed in the partition wall 23.

The flow rate detection sensor 3 for the high flow rate region
7 is configured to detect a flow rate of the gas passing between the inlet 37a and the outlet 37b, and output a detection signal corresponding to the detected flow rate to a microcomputer (not shown).
The flow rate detection sensor 43 for the low flow rate region has an inlet 43.
It is configured to detect the flow rate of the gas passing between a and the outlet 43b, and output a detection signal corresponding to the detected flow rate to the microcomputer (not shown).

As shown in FIG. 2, the bottom 7 is
The lower end of each of the first to fourth chambers 13, 15, 19, and 45 is configured to be closed in a state where the lower end of the body 5 is assembled. Reference numeral 49 in FIG. A flow rate indicator by a provided liquid crystal display, a reference numeral 51 in FIG.
Reference numeral 53 denotes an electromagnetic solenoid for driving the shutoff valve 51 to open and close.

In the housing 1 described above, the main flow path 33 of the measuring unit 31 and the first chamber 1
3, the valve port 27, and the second chamber 15,
The gas flowing into the inside from the gas inlet 9 is supplied to the gas outlet 11
A main flow path corresponding to the gas flow path in the claims is configured to guide the flow through the main flow path. Of these, the main flow path portion excluding the second chamber 15 corresponds to the high flow path in the claims. .

In the housing 1 described above,
The sub flow path 35, the communication pipe 39, the third chamber 19, the flow rate detection sensor 43 for the low flow rate region, the fourth chamber 45, and the shutoff valve port 47 of the measuring unit 31 make the valve port 2
A bypass passage corresponding to the low flow passage in the claims is formed, which bypasses the passage 7 and allows passage of gas at a maximum flow rate lower than the maximum flow rate of the valve port 27.

The microcomputer (not shown) multiplies the detection signal from the flow rate detection sensor 37 for the high flow rate range by the ratio of the gas passing flow rate between the flow rate detection sensor 37 for the high flow rate range and the main flow path. The flow rate of the gas passing through the main flow path is measured, and the flow rate of the gas passing through the bypass flow path is measured based on a detection signal from the flow rate detection sensor 43 for the low flow rate area.

Then, based on the measured flow rate of the gas and its time-series change pattern, the microcomputer determines whether or not gas has leaked on the gas consuming source side from the gas outlet 11, and has determined that gas has leaked. In case, electromagnetic solenoid 5
3 to open the shut-off valve port 47 in the open state.
Close with 1.

The flow path switching unit 55 includes a diaphragm 57, a main valve 59 (corresponding to a valve body), and a link mechanism 6 for transmitting power from the diaphragm 57 to the main valve 59.
One.

As shown in FIG. 2, the diaphragm 57 is housed in the diaphragm case 63 with its peripheral portion being sandwiched between the upper case 63a and the lower case 63b of the diaphragm case 63, and is housed in the diaphragm case 63.
In addition, the diaphragm 57 is disposed in an upper portion of the first chamber 13 located in the lid 3 of the housing 1.
A low-pressure chamber 65 is formed between the upper surface 57a (corresponding to the other surface) and the upper case 63a, and a high-pressure chamber 67 is formed between the lower surface 57b (corresponding to one surface) of the diaphragm 57 and the lower case 63b. Make up.

As shown in FIG. 3, the low pressure chamber 65 has a pressure introducing passage 69 whose lower end communicates with the fourth chamber 45, and an upper case 63 as shown in FIG.
a and a space 71 formed between the cover 3 and the upper case 6.
The high pressure chamber 67 communicates with the second chamber 15 through a through hole 63c formed in the third case 3a and the shutoff valve port 47, and an opening 63d formed in the lower case 63b of the diaphragm case 63. And communicates with the first chamber 13.

The diaphragm 57 has an upper surface 57a.
Due to the elastic force of the coil spring 73 interposed between the upper case 63a and the upper case 63a of the diaphragm case 63, the high pressure chamber 67 shown by a solid line in FIG. Pressure difference between the gas pressure in the first chamber 13 received on the lower surface 57b of the diaphragm 57 and the gas pressure in the second chamber 15 received on the upper surface 57a. Is configured to be vertically displaced between the upper limit position and the lower limit position.

Reference numeral 75 in FIG. 2 denotes an auxiliary arm having both ends pivotally connected to the center of the lower surface 57b of the diaphragm 57 and the peripheral edge of the lower case 63b of the diaphragm case 63, respectively. The diaphragm 57 is configured to swing around a pivot point with respect to the lower case 63b as the diaphragm 57 is vertically displaced.

The main valve 59 is formed with an outer shape slightly larger than the ring member 29 of the valve port 27, and at the approximate center of the upper surface of the main valve 59, an enlarged front view of the flow path switching unit 55 shown in FIG. As shown in the figure, the lower end of the rod-shaped support member 77 is connected, and the upper part of the support member 77 is connected to the periphery of the lower case 63b of the diaphragm case 63 near the position where the auxiliary arm 75 is pivotally attached. The support member 77 is movably supported in the thrust direction by a thrust bearing 81 attached to a tip end of an extended substantially L-shaped bracket 79.

The link mechanism 61 has a support member 7 at the lower end.
7, a second link lever 85 having a lower end pivotally connected to the upper end of the first link lever 83, and one end substantially at an intermediate position of the second link lever 85. And a third link lever 87 pivotally attached thereto. The upper end of the second link lever 85 has a bracket 79
The lower case 63b of the diaphragm case 63 with the extension
Of the third link lever 87
Is pivotally connected to a substantially intermediate portion of the auxiliary arm 75.

A guide frame 89 (corresponding to a guide member) is attached to the front end of the bracket 79.
The guide frame 89 extends horizontally from the bracket 79, and a guide hole 89a is formed in a portion near the front end of the guide frame 89. The guide hole 89a has a diaphragm 57a.
Guide shaft 91 suspended from the center of the lower surface 57b
Is movably inserted in the thrust direction.

As is clear from the above description, in the present embodiment, the lid 3, the body 5, the bottom 7, and the diaphragm case 63 correspond to the housing in the claims, respectively. Of these, the body 5 provided with the valve port 27 corresponds to a housing body in which a predetermined portion of the high flow passage is defined, and the main valve 59 supports the support member 7.
7. Diaphragm case 6 having thrust bearing 81 and lower case 63b supported via bracket 77
Reference numeral 3 corresponds to a housing body provided with a housing portion in the claims.

Next, the operation (operation) of the gas meter of the present embodiment configured as described above, particularly, the flow path switching in the flow path switching unit 55 will be described.

First, assuming that gas is not consumed on the gas consumption source side (not shown), the gas inlet 9 is connected to the gas supply source side (not shown), and the gas outlet 11 is connected to the gas consumption source side. Is connected to the gas meter, the gas does not flow out to the gas consumption source side via the second chamber 15 and the gas outlet 11.

Therefore, at this point, the upper case 63
a through-hole 63c, space 71 in lid 3, pressure introducing passage 6
9 and the diaphragm 57 from the gas in the second chamber 15 communicating with the low-pressure chamber 65 through the shut-off valve port 47.
Of the diaphragm 57 from the pressure received by the upper surface 57a of the diaphragm 57 and the gas in the first chamber 13 communicating with the high-pressure chamber 67.
The diaphragm 57 is moved downward by the resilience of the coil spring 73 and located at the lower limit position on the high-pressure chamber 67 side due to the balance between the pressure received by the coil 7 b and the pressure applied to the diaphragm 7 b.

For this reason, as shown in FIG. 4, the auxiliary arm 75 extends horizontally substantially in parallel with the diaphragm 57 at the lower limit position, and the other end is pivotally attached to a substantially intermediate position of the auxiliary arm 75. A substantially intermediate portion of the second link lever 85 is pushed down by one end of the third link lever 87, and a first link lever 83 having an upper end pivotally connected to a lower end of the second link lever 85; The main valve 59 moves down via the support member 77 having the upper end pivotally attached to the lower end of the lever 83, and the main valve 59 is seated on the upper end of the ring member 29 to close the valve port 27.

In this state, when gas consumption starts on the gas consumption source side, the second chamber 15 and the gas outlet 11 are closed because the valve port 27 is closed by the main valve 59.
Gas flows out to the gas consumption source side via
From the gas inlet 9, the sub flow path 35 of the measuring unit 31, the communication pipe 39, the third chamber 19, the flow rate detection sensor 43 for the low flow rate area 43, the fourth chamber 45, and the shutoff valve port 47
The gas flows into the second chamber 15 through the gas outlet, and further flows out to the gas consumption source side through the gas outlet 11.

The flow rate of the gas in this state is measured by the microcomputer (not shown) based on the detection signal from the flow rate detection sensor 43 for the low flow rate area.

Further, as described above, when the main valve 59 closes the valve port 27, the gas consumption increases on the gas consumption source side, and the second chamber 15 and the gas outlet 11
The flow rate of the gas flowing out to the gas consumption source side increases, and the pressure received on the upper surface 57a of the diaphragm 57 from the gas in the second chamber 15 and the lower surface 57b of the diaphragm 57 from the gas in the first chamber 13 When the balance with the received pressure changes, the diaphragm 57 is displaced from the lower limit to the upper limit against the elastic force of the coil spring 73.

Then, the auxiliary arm 75 pivotally attached to the center of the lower surface 57b of the diaphragm 57 swings about the pivot point at the periphery of the lower case 63b of the diaphragm case 63. 5 is a channel switching unit 55
As shown in the enlarged front view of FIG. 5, the substantially middle portion of the second link lever 85 is pulled upward by one end of the third link lever 87 whose other end is pivotally connected to the substantially middle portion of the auxiliary arm 75, The main valve 59 moves upward through a first link lever 83 having an upper end pivotally connected to the lower end of the two link lever 85 and a support member 77 having an upper end pivotally connected to the lower end of the first link lever 83. The main valve 59 is separated from the upper end of the ring member 29, and the valve port 27 is opened.

Therefore, as the gas flows out to the gas consuming source side via the second chamber 15 and the gas outlet 11, the gas flows from the gas inlet 9 to the main flow path 3 of the measuring unit 31.
3, gas flows into the second chamber 15 through the first chamber 13 and the valve port 27, and the sub flow path 35, the communication pipe 39, the third chamber 19, and the flow rate detection for the low flow rate region of the measuring unit 31 Gas flows into the second chamber 15 via the sensor 43, the fourth chamber 45, and the shut-off valve port 47, and further, the gas flows into the second chamber 1 through these two paths.
The gas that has flowed into 5 flows out to the gas consumption source side through the gas outlet 11.

The gas flow rate in this state is measured by the microcomputer (not shown) based on a detection signal from the flow rate detection sensor 37 for the high flow rate region.

When the diaphragm 57 is vertically displaced between the upper and lower limits as described above, the guide shaft 91 vertically suspended from the center of the lower surface 57b of the diaphragm 57 moves up and down together with the diaphragm 57, This movement is guided by the guide hole 89a of the guide frame 89 into which the guide shaft 91 is inserted, thereby suppressing the displacement of the diaphragm 57 in the horizontal direction due to the vertical displacement of the diaphragm 57 and the inclination of the diaphragm 57 with respect to the horizontal direction. Is done.

As described above, due to the change in the balance between the gas pressure received by the upper surface 57a and the gas pressure received by the lower surface 57b, the diaphragm 57 is vertically displaced between the upper limit position and the lower limit position. Follow the link mechanism 61
When the main valve 59 opens and closes the valve port 27, the main valve 59
The weight of the lower valve 57b of the diaphragm 57 to which the main valve 59 is connected via the support member 77 and the link mechanism 61
Of the diaphragm case 63 connected to the support member 77 via the first and second link levers 83 and 85, not directly at the center of the lower case 63b. Become.

The movement direction of the main valve 59 when the main valve 59 opens and closes the valve port 27 following the vertical displacement of the diaphragm 57 is the vertical direction. Since there is no need to convert the displacement into a displacement in the horizontal direction, power transmission loss from the diaphragm 57 to the main valve 59 hardly occurs in the link mechanism 61.

When adjusting the degree of contact of the main valve 59 with the valve port 27, the lid 3 is removed from the body 5 and the diaphragm case 63 arranged on the upper part of the first chamber 13 is removed, and the link mechanism is removed. In a state where the first chamber 13 is separated from the body 5, or before the diaphragm mechanism 63 is disposed on the upper portion of the first chamber 13 and the link mechanism 61 and the lid 3 are assembled to the body 5, the first chamber 13 is closed. With the valve port 27 and the ring member 29 exposed at the upper opening of the valve port 27, the ring member 29 is screwed with respect to the valve port 27 to increase or decrease the amount of protrusion from the upper end of the valve port 27.

As described above, according to the present embodiment, after the gas is introduced into the housing 1 from the gas inlet 9 connected to the gas supply source side and is led out of the housing 1 from the gas outlet 11, In the gas meter that measures the flow rate of the gas flowing toward the consuming source, the gas consumption by the gas consuming source is small and the flow rate of the gas flowing inside the housing 1 is low. The pressure of the gas received by the upper surface 57a of the diaphragm 57 and the lower surface 57 vary depending on the flow rate of the flowing gas.
When the diaphragm 57 is vertically displaced by a change in the balance between the pressure of the gas received by b and the displacement is transmitted to the main valve 59 by the link mechanism 61, the valve port 27 is opened and closed by the main valve 59. The following configuration was adopted.

That is, the main valve 5 for opening and closing the valve port 27
The valve port 27 and the main valve 59 are arranged in the housing 1 so that the direction of movement of the valve 9 is in the same vertical direction as the direction of displacement of the diaphragm 57, and the main valve is connected via the support member 77 and the first link lever 83. Link mechanism 6 connected to 59
The upper end of the first second link lever 85 is connected to the first chamber 13.
Diaphragm case 6 placed on the upper torso 5
3 to be pivotally attached to the periphery of the lower case 63b.

Therefore, the weight of the main valve 59 is exclusively applied to the periphery of the lower case 63b of the diaphragm case 63, and the first valve 59 is not directly applied to the diaphragm 57.
Even if the difference between the gas pressure in the chamber 13 and the gas pressure in the second chamber 15 is small, the diaphragm 57 can be displaced up and down, and the power transmission loss from the diaphragm 57 to the main valve 59 is reduced by the link mechanism. Since almost no power is generated in the valve 61, the loss at the time of power transmission in the link mechanism 61 is suppressed, and the valve port 27 is opened and closed by the main valve 59 even with a slight change in the gas flow rate, so that the flow path corresponding to the gas flow rate is changed. Switching can be performed efficiently with good reactivity.

In the present embodiment, the lid 3, the body 5, the bottom 7, and the housing 1 are vertically divided.
In the gas meter constituted by the diaphragm case 63, the valve port 27 opened and closed by the main valve 59 is disposed on the body 5 so as to open upward in accordance with the opening and closing movement direction of the main valve 59. By separating the lid 3 and the diaphragm case 63 and exposing the valve port 27 and the ring member 29 to the upper opening of the first chamber 13,
Valve port 27 without being disturbed by link mechanism 61 or main valve 59
By adjusting the amount of protrusion of the ring member 29 from the upper end of the valve port 27, the degree of contact of the main valve 59 with the valve port 27 can be adjusted.

The lower case 6 of the diaphragm case 63
A guide frame 89 attached to a peripheral portion of the guide frame 3b via a bracket 79, and a guide hole 89a of the guide frame 89 which is vertically suspended from the center of the lower surface 57b of the diaphragm 57.
The guide shaft 91 whose distal end is movably inserted in the thrust direction may be omitted, but if these are provided as in the present embodiment, the guide frame 8 can be omitted.
Nine guide holes 89a guide the guide shaft 91, thereby suppressing the displacement of the diaphragm 57 in the horizontal direction due to the vertical displacement and the inclination with respect to the horizontal direction, so that the diaphragm 57 can be smoothly displaced in the vertical direction. So it is advantageous.

Further, as described above, in the present embodiment, the present invention is applied to a gas meter constituted by the lid 3, the body 5, the bottom 7, and the diaphragm case 63 in which the housing 1 is divided vertically. Although the case has been described, the present invention has a configuration in which the valve body is opened and closed by the vertical displacement of the diaphragm in accordance with the flow rate of the gas to switch the gas flow path, for example, a gas metering device including a gas leak detection device The same can be applied to
Of course.

[0062]

As described above, according to the flow path switching mechanism of the gas metering device according to the first aspect of the present invention, the high flow passage whose predetermined portion is opened and closed by the valve body, A low flow passage that allows gas to pass at a maximum flow rate lower than the maximum flow rate of the high flow passage at least in the gas flow path, and A diaphragm for receiving the gas pressure in the high flow passage portion on the upstream side of the gas flow from the predetermined location in the high flow passage on one surface and receiving the gas pressure in the low flow passage on the other surface; A flow path switching mechanism of a gas metering device that drives the valve element to open and close according to the flow rate of gas flowing through the gas flow path by transmitting the displacement in the vertical direction to the valve element via a link mechanism. And the opening and closing direction of the valve element is A support member connected to the valve body can be moved in a vertical direction at a housing position displaced at least in a vertical direction from the diaphragm in a housing that is disposed so as to face downward and displaceably supports the diaphragm. And the link mechanism is interposed between the diaphragm and the support member, and has a link lever supported by the housing.

For this reason, the loss at the time of power transmission in the link mechanism is suppressed by the amount that the displacement of the diaphragm transmitted to the valve body by the link mechanism does not need to be changed halfway, and the weight of the valve body is reduced by the supporting member. The amount of change in the gas pressure difference between the upstream side and the downstream side of the predetermined location required for the vertical displacement of the diaphragm is reduced by the amount that does not directly apply to the diaphragm applied to the housing via
Even with a slight change in the gas flow rate, the valve can be opened and closed efficiently and the flow path can be switched with good reactivity.

Further, according to the flow path switching mechanism of the gas metering device of the present invention described in claim 2, in the flow path switching mechanism of the gas metering device of the present invention described in claim 1, the housing portion has the same structure as that of the gas metering device. A guide shaft that is displaced horizontally from the center of the diaphragm and that extends in the up-down direction is connected to the center of the diaphragm, and the guide shaft is vertically inserted into a guide hole of a guide member extending from the housing. It is configured to be inserted movably in the direction.

For this reason, in the flow path switching mechanism of the gas metering device according to the present invention, the posture of the diaphragm is always kept horizontal by the guide of the guide shaft by the guide hole of the guide member. The difference in gas pressure between the upstream side and the downstream side acts in a direction inclined from the up-down direction, so that loss of displacement of the diaphragm can be suppressed.

According to a third aspect of the present invention, there is provided a gas meter having a flow path switching mechanism for a gas meter according to the first or second aspect, wherein the housing is divided in a vertical direction. And the housing portion is provided in a housing member different from the housing member in which the predetermined portion of the high flow passage is formed.

For this reason, when the gas meter employs the flow path switching mechanism of the gas metering device according to claim 1 or 2, the degree of contact between the valve body and the valve seat at a predetermined position opened and closed by the valve seat is adjusted. In the case where a configuration for performing the adjustment is provided at a predetermined location side, the adjustment work is performed by separating the housing body having the housing location where the valve body is supported via the support member from the housing body where the predetermined location is provided. Then, from the open upper or lower end of the housing body in which the predetermined portion is provided, approach the configuration for adjusting the valve seat position of the predetermined portion exposed at the end portion, and perform the adjustment work on the valve body. It can be done easily without distraction.

[Brief description of the drawings]

FIG. 1 is a front view showing a schematic configuration of an electronic gas meter according to an embodiment of the present invention.

2 is a longitudinal sectional view of the housing of FIG. 1 in a state where a diaphragm is located at a lower limit position.

FIG. 3 is a plan view of a trunk of FIG. 1;

4 is an enlarged front view of the flow path switching unit of FIG. 2 in a state where a valve port is closed by a main valve.

5 is an enlarged front view of the flow path switching unit of FIG. 2 in a state where a valve port is opened by a main valve.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Housing 3 Cover part (housing body) 5 Body part (housing body in which a predetermined part of a high flow passage is formed) 7 Bottom part (housing body) 13 First chamber (gas flow path, high flow passage) 15 second Chamber (gas flow path) 19 Third chamber (gas flow path, low flow passage) 27 Valve port (gas flow passage, high flow passage, predetermined location) 33 Metering unit main flow passage (gas flow passage, high flow passage) ) 35 Measuring unit sub flow path (gas flow path, low flow path) 39 communication pipe (gas flow path, low flow path) 43 low flow rate flow rate detection sensor (gas flow path, low flow path) 45 th 4 chamber (gas flow passage, low flow passage) 47 Shut-off valve port (gas flow passage, low flow passage) 57 diaphragm 57a upper surface of diaphragm (other surface of diaphragm) 57b lower surface of diaphragm (diaphragm of diaphragm) 59) Main valve (valve element) 61 Link mechanism 63 Diaphragm case (housing body provided with housing part) 63b Diaphragm case lower case (housing part) 77 Support member 85 Second link lever 89 Guide frame (guide member) 89a Guide hole 91 Guide shaft

Claims (3)

[Claims] A high flow passage whose predetermined location is opened and closed by a valve element, and a gas having a maximum flow rate lower than a maximum flow rate of the high flow passage by bypassing at least the predetermined location of the high flow passage. Having a low flow passage that allows passage of the gas flow passage in the middle of the gas flow path, and the gas pressure in the high flow passage portion of the high flow passage that is more upstream of the gas flow than the predetermined location. By transmitting the vertical displacement of the diaphragm which receives the gas pressure in the low flow passage on the other surface while receiving the gas pressure in the one surface, the valve body through the link mechanism is transmitted to the gas flow path. A flow path switching mechanism of a gas metering device that drives the valve element to open and close according to a flow rate of gas, wherein the valve element is disposed so that the opening and closing direction of the valve element is up and down. Housing for supporting the displaceable A support member connected to the valve body is supported movably in the up-down direction at least in a housing portion displaced in the up-down direction from the diaphragm, and the link mechanism is interposed between the diaphragm and the support member. A flow path switching mechanism for the gas metering device, wherein the flow path switching mechanism is provided with a link lever supported by the housing. 2. The housing portion is horizontally displaced from the center of the diaphragm, and a guide shaft extending vertically is connected to the center of the diaphragm, and the guide shaft is displaced from the housing portion. 2. The flow path switching mechanism for a gas metering device according to claim 1, wherein the flow path switching mechanism is vertically movably inserted into a guide hole of an extended guide member. 3. A gas meter having a flow path switching mechanism of a gas metering device according to claim 1, wherein the housing is constituted by a plurality of housing bodies divided in a vertical direction, and the housing portion is provided. Is provided in a housing body different from a housing body in which the predetermined portion of the high flow passage is formed.