JP3374371B2 - Gas leak detection device - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a gas leakage detection device.

[0002]

2. Description of the Related Art Conventional liquefied propane gas (hereinafter referred to as LP
An abbreviation of G) is a gas leakage detection device for detecting leakage of a gas supply pipe including a buried pipe of a supply facility, and in particular, the gas supply pipe is a gas for a plurality of gas consumers of an apartment house such as an apartment or an apartment. As a gas leakage detection device used when a large amount of gas is required to be supplied at one time, for example, as disclosed in Japanese Patent Application Laid-Open No. 3-41300, a gas leakage detection device that has a small amount depending on the gas flow rate is used. There is a switchable gas leak detection device that can switch between flow rate detection compatible / large flow rate detection compatible.

That is, as shown in FIG. 7, the LPG cylinder 1
A gas supply source such as the above and a gas intake of the condominium 2 are connected by a gas supply pipe 4, and the gas supply pipe 4 is provided with pressure regulators 5, 6 and a gas meter 7. Further, a valve and the like (not shown) are also provided, and a gas meter 8 and a valve (not shown) are provided in the pipe for supplying gas from the gas intake port to the gas consuming facility of each house of the condominium 2.

A parent pressure regulator 6 is provided on a gas supply pipe 4b between a temporary regulator 5 on the LPG cylinder 1 side which is a gas supply source and a parent gas meter 7 which integrates the amount of gas supplied to the entire condominium 2. Further, the gas supply pipe 4b is provided with bypass gas flow paths 14a and 14b for connecting the inlet side and the outlet side of the parent pressure regulator 6. The bypass gas flow paths 14a and 14b are provided with a child pressure regulator 15 and a microcomputer gas meter 16 as a minute leak detection means in this order from the inlet side.

The adjusting pressure of the child pressure adjuster 15 is set higher than the adjusting pressure of the parent pressure adjuster 6. Further, the microcomputer gas meter 16 can accurately measure a minute flow rate (for example, 3 liters / hour or less), and has a minute leak detection function for 30 consecutive days as a threshold value (for example, 3 liters / hour). When there is the above flow rate, it is determined that leakage has occurred, and an alarm means such as lighting of an alarm lamp or ringing of an alarm buzzer is issued to that effect.

In the switching-type gas leakage detection device, the main part of which is configured as described above, the gas consumption amount is increased during the night or on consecutive holidays, that is, during the period when the gas is not used by the consumer or when the user is out. Almost disappears, or the above 3
In the case of an extremely small amount (compared to the case of using a large flow rate in normal times) such as liter / hour, the gas supply pipe 4b
Becomes high, the parent pressure regulator 6 is closed, and gas flows only to the child pressure regulator 15 and the microcomputer gas meter 16. Therefore, the minute flow rate of the gas flowing through the gas supply pipe 4b is controlled by the microcomputer gas meter 16. To monitor. At this time, if the gas consumption is completely stopped and there is no slight leakage, the parent pressure regulator 6
Needless to say, even in the microcomputer gas meter 16,
Neither detects the gas flow rate. In other words, the detection result is that the flow rate is 0.

The so-called flow rate of 0 is at least 1 during a relatively long day such as 30 days.
On the assumption that the frequency will occur, it goes without saying that the parent pressure regulator 6 and the microcomputer gas meter 16 will continue to detect the gas flow rate even if the gas flow rate is minute, without stopping, during this period. The determination means arranged inside the gas meter 16 determines that it is a minute leak as described above, and the warning is given by an alarm means such as lighting an alarm lamp or ringing an alarm buzzer.

As described above, in the conventional technique, the minute flow rate gas leak detection is performed by disposing the minute flow rate measurement bypass device and the minute flow rate detection device such as the microcomputer gas meter 16 in a part of the gas supply path. I am trying.

[0009]

However, as described above, the child pressure adjuster 15 and the minute flow rate detecting device such as the microcomputer gas meter 16 are completely separate from the parent pressure adjuster 6 and the parent gas meter 7 and are dedicated. Since a bypass pipe is additionally provided, the problem that the entire device becomes large and piping work when assembling such a structure becomes very complicated, and the throughput of the work process is significantly reduced. However, there was a problem of causing cost increase.

Further, as the microcomputer gas meter 16 used as the above-mentioned minute flow rate detecting device, a mechanical type volumetric flow meter such as a so-called conventional membrane type was used, but in the membrane type gas meter. Since there is a restriction on the minimum measurable flow rate in general, there is a problem that the flow rate below that cannot be detected. That is, for example, when the flow rate of at least one cycle of the membrane gas meter is 0.7 liter, and when a gas of a flow rate corresponding to this flow rate leaks, the occurrence of the gas leak should be immediately detected at the time of occurrence. I can't. For example, when there is a pipe leak that produces a minute gas flow rate of 3 liters / hour, the flow rate measurement can be completed by the membrane meter whose flow rate in one cycle is 0.7 liter. (0.7 ÷ 3) × 60 = 14 minutes, and the measurement cannot be performed within 14 minutes. In other words, unless gas use is stopped for 14 minutes or more in the above-mentioned apartment house for 30 days, it cannot be detected as gas use stop. There has been a problem that even the operation for detecting minute leaks cannot be performed accurately. Alternatively, even if such a slight leak detection operation can be performed, it is impossible to instantaneously detect the flow rate at that time, so that there is a problem that rapid measurement cannot be performed.

Further, the microcomputer gas meter 16 as described above is used as a minute flow rate detecting device, but since it measures a minute flow rate, minute errors due to various disturbances are mixed in the measurement data. It is extremely inconvenient to do so, and much more precise measurement is strictly required than that of a normal gas meter. In particular, if a minute flow rate cannot be accurately measured due to such an error, even if a minute gas leak occurs, it cannot be detected or alarmed, which leads to a dangerous situation. There is a problem that the probability may increase.

That is, as the minute flow rate sensor used as the minute flow rate detecting device such as the microcomputer gas meter 16, a particularly sensitive flow rate detecting function is required to detect the minute flow rate. In the flow rate sensor, for example, the gas flow that flows into the microcomputer gas meter 16 side through the child pressure adjuster 15 described above has a joint of the pipe, a bent portion in the conduction path, and various other hydrodynamic resistances. As a result, the influence thereof causes a bias or pulsation in the flow velocity, which becomes a disturbance error and is mixed in the measurement data, and is detected by the minute flow rate sensor in the minute flow rate detection device such as the microcomputer gas meter 16. An inaccurate and unreliable minute flow rate measurement value including the above error is measured. As a result, there is a problem that only gas leak detection with low reliability can be performed.

Moreover, when the child pressure regulator 15-the bypass gas flow passage 14a-the microcomputer gas meter 16-the bypass gas flow passage 14b are further miniaturized or shortened in accordance with the above-mentioned demand for miniaturization, the gas flow becomes Since the child pressure regulator 15 suddenly flows into the microcomputer gas meter 16 via the bypass gas flow passage 14a, and also flows out from the microcomputer gas meter 16 to the bypass gas flow passage 14b, the gas is particularly generated. When the pressure regulator 15 suddenly flows into the microcomputer gas meter 16, the drain of oily fat-like sludge (impurities mixed during LPG refining, etc.) and water mixed in the gas is stored in the microcomputer gas meter 16. It may invade or adhere to the internal flow rate sensor or other main parts or structures such as conducting paths, resulting in deterioration of their functions. There is an eclipse or a problem that causes the damage.

The present invention has been made to solve such a problem. The present invention relates to a switching-type gas leakage detection device equipped with a minute leakage detection device such as a child pressure regulator 15 and a microcomputer gas meter 16 for detecting a minute amount of gas leakage, and downsizing the entire device. It is possible to achieve simplification of the structure and the structure, and to maintain an extremely small error due to the minute flow rate detection, so that accurate and reliable minute flow rate leak detection can be realized. Durability is improved by solving the problem that the drain of moisture etc. invades or adheres to the minute leak detection device and prevents functional deterioration, corrosion or damage of the flow sensor and various structures in the minute leak detection device. It is an object of the present invention to provide a switch-type gas leakage detection device equipped with the above-mentioned minute leakage detection device.

[0015]

First, a gas leakage detection device of the present invention comprises a parent pressure adjuster provided in a gas supply pipe for conducting gas supplied from a gas supply source, and the parent pressure adjuster. A bypass gas flow passage having an inlet connected to the upstream side of the parent pressure regulator and an outlet connected to the downstream side of the parent pressure regulator, and adjusting the parent pressure regulator provided in the bypass gas flow passage. A child pressure regulator that is adjusted to a regulated pressure higher than the pressure, and a gas that is arranged on the downstream side of the gas flow with respect to the child pressure regulator in the bypass gas flow path and that measures the flow rate of the gas. With a flow rate measuring means,
In a gas leak detection device capable of detecting that the gas is continuously flowing for a predetermined time by the gas flow rate measuring means and determining that a gas leak has occurred on the downstream side of the parent pressure regulator. The gas flow rate measuring means is provided with a conduction path for conducting the gas, and the gas in the flow rate range up to the maximum value corresponding to the adjustment pressure of the child pressure regulator and the cross-sectional area of the conduction path in the conduction path. A gas flow rate measuring means using an instantaneous flow rate measurement sensor capable of measuring an instantaneous flow rate, wherein the gas flow rate measuring means is provided on the upstream side of the instantaneous flow rate measurement sensor in the conduction path and is hydrodynamic with respect to the flow of the gas in the conduction path. become a resistance in a vertical cross-sectional direction component, the moth
Position and velocity distribution within the cross section of the conduit and temporal
It is characterized in that it is provided with a labyrinth structure for making the pulsating flow change uniform . Second, the gas leakage detection device of the present invention
Is the gas leakage detection device according to claim 1,
Between the flow rate measuring sensor and the labyrinth structure,
Hydrodynamic perpendicular to the gas flow in the passage
It becomes the resistance of the component in the cross-sectional direction, and disconnects the conduction path of the gas.
Uniformization of positional flow velocity distribution and temporal pulsation change in the plane
It is characterized by further including a mesh structure that
It

That is, according to the present invention, the instantaneous flow rate measurement capable of measuring the instantaneous flow rate of the gas is provided as the gas flow rate measuring means arranged in the bypass gas flow path downstream of the slave pressure regulator to measure a so-called minute flow rate. By using a sensor,
As a conventional problem, it becomes possible to instantaneously measure the flow rate instantaneously, which is impossible with the conventional membrane meter as pointed out above.

Moreover, since the body of the above-mentioned instantaneous flow rate measuring sensor can generally be made extremely small as compared with the conventional membrane type, the gas flow rate measuring means, which is a minute leak detecting device, is drastically downsized. And as a result,
The overall size of the gas leakage detection device can be dramatically reduced.

Here, the above-mentioned instantaneous flow rate measuring sensor according to the present invention is a so-called guessing method (or in some documents, also referred to as an estimation method) which changes in accordance with the flow rate of the gas flow. A method that measures various physical quantities and calculates the gas flow rate based on the measured values, that is, a differential flow meter pressure method that measures the dynamic pressure due to the gas flow, an area flow rate measurement method that measures the viscous resistance of the gas flow, , A turbine flow rate measurement method that measures the power of the gas flow to move the turbine blades, a vortex flow rate measurement method that measures the frequency of the vortex generated in the gas flow, the propagation time of ultrasonic waves in the gas flow, An ultrasonic flow rate measuring method for measuring the propagation velocity and the like is particularly suitable. Alternatively, a thermal mass flow rate measuring method in which a heating wire is arranged in a gas flow and a temperature change before and after the heating wire is measured can be preferably used.

Further, according to the present invention, in addition to the above-described actions and effects, a fluid dynamics that intersects with the gas flow in the conduction path perpendicularly to the upstream side of the instantaneous flow rate measuring sensor in the conduction path. Of the positional flow velocity of the gas in the cross section of the conducting path and temporal pulsation change.
A labyrinth structure to homogenize, or a labyrinth structure and
Since it has a mesh structure and a mesh structure, it is possible to eliminate the bias and pulsation of the gas flow velocity, which has been a conventional problem and which is a cause of a disturbance error that is mixed in the measurement data.
And as a result, it is possible to accurately measure the gas flow with a uniform flow velocity distribution without pulsating flow in such a conduit,
Accurate gas leak detection can be realized.

Furthermore, the labyrinth structure and the mesh structure described above, in addition to the effect of rectifying the gas flow or the effect of equalizing the flow velocity distribution as described above, pose a problem in the conventional minute flow rate detecting device as described above. It is possible to prevent such oil-like sludge (impurities mixed during LPG refining) and water from entering the drain passage, etc., just like a filter. In other words, in addition to the effect of achieving accurate measurement as described above, a filter effect that prevents the intrusion of foreign matter such as drain can be achieved, so it is possible to function as one bird and two birds with a simple structure. Is also effective and preferable.

[0021] Third, the gas leakage detection device of the present invention, the gas leakage detection device of the first or second aspect, said child pressure regulator and the master pressure regulator and bypass gas flow path and the gas flow rate measurement The feature is that the means are integrated. That is, according to the present invention, as described in the technique of the first aspect, it is possible to dramatically reduce the size of the gas flow rate measuring means, which is the micro leak detection device. That is, the child pressure regulator, the bypass gas flow passage, and the gas flow rate measuring means can be integrated more compactly, and if they can be made compact in this way, they are arranged integrally with the parent pressure regulator. It is also possible, and as a result,
The child pressure regulator, the parent pressure regulator, the bypass gas flow path, and the gas flow rate measuring means can be integrated in an extremely compact manner, and the gas leak detection apparatus as a whole can be dramatically reduced in size. You can That is, by adopting the technique described in the first aspect, as a further ripple effect, it is possible to achieve an extremely compact integration of such respective constituent elements.

[0022] Fourth, the gas leakage detection device of the present invention, the gas leakage detection device according to any one of the first to third, wherein the gas is flowing continuously a predetermined time by the gas flow measuring means When it is detected that gas leakage has occurred on the downstream side of the parent pressure regulator, and gas leakage determination means for determining that gas leakage has occurred on the downstream side of the parent pressure regulator by the gas leakage determination means. If it is determined that the gas leak has occurred, an alarm means for alarming at least one of a visual medium and an audible medium is provided.

The above-mentioned gas leakage determination means and alarm means may be provided inside the outer casing (so-called body) of the gas leakage detection device itself according to the present invention, or arranged so as to be attached thereto. May be. That is, the difference between the technique described in the fourth aspect and the technique described in the first aspect is that in the case of the first aspect, the gas leakage determination means and the alarm means are formed as the gas leakage detection device itself or integrally therewith. It was also possible to use it as a separate device that can be arranged at a position distant from the constituent elements, but in the gas leakage detection device according to the third aspect, the gas leakage determination means and the alarm means are the gas leakage detection device itself. It is characterized by being installed in or attached to.

As a result, in addition to the above-mentioned miniaturization, the gas leakage detection device according to the present invention itself completely comprises all the means for detecting a gas leakage to the means for issuing an alarm. As a result, the unit as a whole is extremely well integrated and can be made compact, and when installing it, there is no need to attach a separate alarm means or the like, and the gas leakage detection according to the present invention can be achieved. Since it is only necessary to attach the device main body, workability and labor at the time of attachment can be effectively realized.

[0025] Fifth, the gas leakage detection device of the present invention, the gas leakage detection device of the fourth aspect, said child pressure regulator and the master pressure regulator and bypass gas flow path and the gas flow measuring means and The gas leakage determination means and the alarm means are integrated.

That is, according to the fifth aspect of the present invention, the child pressure regulator, the parent pressure regulator, the bypass gas flow path, the gas flow rate measuring means, the gas leakage determining means, and the alarm means are integrated. ing. In other words, since almost all the main means involved in the gas leak warning are integrated, in addition to the technique described in the fourth aspect, the unit as a whole is extremely well integrated and compact. Moreover, since it is not necessary to separately attach a separate alarm means or the like when installing it, only the gas leakage detection device body according to the present invention needs to be attached. Can be simplified.

Further Sixth, gas leakage detection device of the present invention, the gas leakage detection device according to any one of the first to fifth, the bypass gas flow passage from the downstream side outlet of the child pressure regulator It is characterized in that the cross section of the passage of the gas at least up to the outlet of the conduction passage of the instantaneous flow rate measurement sensor is arranged to have a constant size and shape.

That is, by arranging the cross sections of the gas passages to have a constant size and shape in this manner, the flow velocity distribution is uneven or pulsating in the gas flow when there is a step in the gas passage as in the conventional case. Since it is possible to prevent the occurrence of a vortex (however, it is needless to say that it is not a vortex for measuring the vortex flow rate), it is possible to accurately measure a minute flow rate of the gas flow.

[0029] Seventh, the gas leakage detection device of the present invention, the gas leakage detection device according to any one of the first to sixth, the bypass gas flow passage from the downstream side outlet of the child pressure regulator It is characterized in that the friction coefficient of the inward wall surface of at least a straight part of the passage of the gas up to at least the outlet of the communication passage of the instantaneous flow rate measurement sensor is made uniform.

In the sixth aspect of the invention, the cross sections of the gas passages are made uniform in size and shape so that the gas flow can be conducted as smoothly as possible without unevenness or disturbance. However, as the means for realizing such smooth gas flow conduction, the technique described in the seventh aspect is also suitable.

That is, since the friction coefficient of the inward wall surface of at least the straight portion of the gas passage is constant,
Since the gas flow passing through the gas passage is subjected to uniform frictional resistance, the uniformity of the gas flow is not impaired. Moreover, at this time, it is, of course, more desirable to set the friction coefficient of the inward wall surface of the gas passage to a value as low as possible. This is because the smaller the frictional force that the gas flow receives from the inward wall surface, the smaller the gradient of the flow velocity distribution in the cross section and the more uniform flow velocity distribution.

At this time, when the technique of the seventh aspect is used in combination with the technique of the fifth and sixth aspects, the instantaneous flow rate from the downstream side outlet of the child pressure regulator via the bypass gas flow path. The length of the gas passage up to the outlet of the measuring passage is extremely compact, and if such a miniaturization and integration is possible,
Since the gas passage can be made extremely short even when a normal pipe is used, if the friction coefficient is uniform over the length, the flow velocity loss of the gas flow due to the friction received by it is extremely small. Making the friction coefficient of the inner wall of the member having such a short passage size uniform can facilitate the step of polishing the inner wall surface, for example. On the contrary, in the case of a conventional gas passage having a large structure that uses a conventional long pipe or the like as the gas passage, the inner wall surface polishing process or the like is performed over the entire length of the long pipe or the like. Since such a process is required, such a process becomes extremely complicated, and is practically inconvenient in terms of feasibility.

Alternatively, the passage for the gas is not limited to the gas pipe as described above, but may be arranged by utilizing a part of the outer casing of the die cast block of the gas leakage detection device, for example. Therefore, even when the gas passage is formed by such die casting, the friction coefficient of the inner wall surface of the passage, that is, the in-plane smoothness can be controlled easily and reliably. Needless to say, if further smoothness is required, further steps such as polishing may be performed. Also in this case, since the length of the passage is made compact and extremely short, the polishing step can be performed very easily, which is also preferable.

Eighth , in the gas leakage detection device according to any one of the first to seventh aspects, the labyrinth structure and the mesh structure are detachably arranged with respect to the conducting path. There is. That is, since the labyrinth structure and the mesh structure both function as a filter for foreign matters such as drains as described above, they gradually become soiled with foreign matters such as water and oil sludge during continuous use, For a longer period of time, however, the resistance to the gas flow conduction may become too great. In particular, in recent years, the service life or usable life of one gas meter system or one gas leak detection device tends to be further extended by a significant improvement in the performance of temporary batteries in the power supply system. The number of years in which one gas leakage detection device can be continuously used tends to be further extended in step with each other. Therefore, during such a long period of use, the labyrinth structure and the mesh structure may become contaminated, which may cause a decrease in measurement function and a measurement error.

Therefore, the labyrinth structure and the mesh structure are detachably arranged with respect to the conducting path.
That is, by making it replaceable, the inconveniences as described above can be completely eliminated, and continuous use for a long period of time can be dealt with. Ninth , the gas leakage detection device of the present invention is the gas leakage detection device according to the sixth aspect , wherein the member of the gas passage is fitted into a portion having a locally wide cross section, It is characterized in that it is provided with a ring-shaped fitting member for aligning the cross section of the passage with a constant size and shape.

That is, in a member forming the gas passage, for example, a forming member such as a connecting portion between a bypass gas flow path formed by using a small gas pipe and a child pressure regulator, a joint member for screw connection is used. Alternatively, the cross section of the gas passage may be uneven due to a member such as an airtight flange. Due to such unevenness, the gas flow causes a large deviation in the flow velocity distribution in the cross section or a pulsating flow, so that the cross section of the cross section of the gas passage should be evenly distributed. It is possible to fit and arrange the ring-shaped fitting member in the portion where the width is wide, and to make the same cross-sectional dimension as the narrow cross-section portion other than that portion. In addition, the ring-shaped fitting member is formed in a shape having a gentle gradient in a direction parallel to the gas conduction direction, and for example, the member such as the airtight flange or the like protruding inward of the gas passage. If it is placed before and after, the gas flow in that part can be passed smoothly, so even if only a ring-shaped fitting member is placed in that part, the gas flow caused by the overhanging part such as the above-mentioned airtight flange It is also possible to prevent the generation of vortices inside.

[0037]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of a gas leakage detection device according to the present invention will be described below in detail with reference to the drawings. FIG. 1 is a diagram showing a main part of a configuration of a gas leakage detection device according to the present invention, and FIG. 2 is a diagram showing a schematic configuration of a main part of an entire gas supply system in which it is incorporated and used.
In FIG. 2, the same parts as those of the conventional configuration shown in FIG. 7 are designated by the same reference numerals for simplification of description and illustration.

This gas leakage detection device is used in the LPG cylinder 1.
Such as gas supply pipe 4 for conducting gas supplied from a gas supply source, and parent pressure regulators 5 and 100 provided in the gas supply pipe 4 (this parent pressure regulator 100 is related to the function of gas pressure regulation). Corresponds to the conventional parent pressure regulator 6, but it is needless to say that its structure is integrated with other constituent elements as will be described later). A bypass gas flow path 101 having an inlet connected to the upstream side and an outlet connected to the downstream side of the parent pressure regulator 100 so as to bypass 100.
(Not shown in FIGS. 1 and 2) and a child pressure regulator 102 provided in the bypass gas flow path 101 and adjusted to a higher regulation pressure than the parent pressure regulator 100.
And an instantaneous flow rate measurement sensor 103, which is a gas flow rate measurement unit that is arranged in the bypass gas flow path 101 on the downstream side of the child pressure regulator 102 and that measures the flow rate of the gas.
(Detailed later) is provided, and the instantaneous flow rate measurement sensor 103, which is the gas flow rate measurement means, detects that the gas is continuously flowing for a predetermined time, and detects the parent pressure regulator 100. In the gas leakage detection device that determines that gas leakage has occurred on the downstream side, the instantaneous flow rate measurement sensor 103 that is the gas flow rate measurement means is a gas flow rate measurement means that includes a conduction path 104 that conducts gas. It is possible to measure the instantaneous flow rate of the gas in the flow rate region up to the maximum value corresponding to the adjustment pressure of the child pressure regulator 102 in the conduction path 104 and the cross-sectional area of the conduction path.

Then, on the upstream side of the instantaneous flow rate measuring sensor 103 in the conduction path 104, a resistance of a component in a vertical cross-section which is hydrodynamic with respect to the flow of the gas in the conduction path 104 becomes a resistance of the gas. The labyrinth structure 201 and the mesh structure 202 that uniformize the positional flow velocity distribution and the temporal pulsating flow change in the cross section of the conducting path are provided. In particular, the instantaneous flow rate measurement sensor 10 using such labyrinth structure 201 and mesh structure 202
The main internal structure of the whole 3 is shown in the partial cut-off diagram of FIG. Reference numeral 105 in the figure is a sensor body including the sensor element (not shown) and the conduction path 104.

Further, when it is detected by the instantaneous flow rate measuring sensor 103 which is the gas flow rate measuring means that the gas is continuously flowing for a predetermined time, a gas leak occurs on the downstream side of the parent pressure regulator 100. Gas leakage determination means 301 for determining that the gas leakage determination means 3
When it is determined by 01 that a gas leak has occurred on the downstream side of the parent pressure regulator 100, an alarm means 30 for giving an alarm of the occurrence of the gas leak with a visual medium and an audible medium.
It has 2 and. In the present embodiment, the gas leakage determination means 301 is arranged inside the outer casing of the alarm means 302 so as to be integrated with the alarm means 302.

Moreover, the child pressure adjuster 102, the parent pressure adjuster 100, and the bypass gas flow path 101 described above.
Also, the instantaneous flow rate measuring sensor 103, which is the gas flow rate measuring means, the gas leak determining means 301, and the alarm means 302 are all attached integrally on the outer casing of the parent pressure regulator 100.

The labyrinth structure 201 and the mesh structure 202 are detachably arranged with respect to the conducting path 104. That is, as shown in the outline in FIG.
The main body (outer casing) 03 is detachable from the bypass gas flow passage 101, and in this detached state, the labyrinth structure 201 and the mesh structure 202 can be detachably attached to the conducting passage 104.

Further, the member for forming the gas passage between the outlet on the downstream side of the child pressure regulator 102 and the instantaneous flow rate measurement sensor 103 via the bypass gas flow passage 101 has a locally wide cross section. It is equipped with ring-shaped fitting members 203, 203 'which are fitted to the portion where the cross sections of the gas passages are made uniform in size and shape. In particular, the ring-shaped fitting member 203 ′ is formed such that the inner surface thereof has a gently sloping shape, and by approximately equalizing the cross-sectional dimensions, it is possible to prevent a rapid change in the cross-sectional area, and It is intended to eliminate eddies and bias in flow velocity.

Further, as shown in FIG. 3, the bypass gas flow path 1 extends from the downstream outlet of the child pressure regulator 102.
01 through at least the instantaneous flow rate measurement sensor 103
The cross-sectional dimensions and shapes of the gas passages up to are substantially uniform and formed so that there are no particularly steep steps. However, this does not apply to the entrance and exit portions of the labyrinth structure 201 and the mesh structure 202. As long as the labyrinth structure 201 and the mesh structure 202 can act more effectively, the labyrinth structure 201 and the mesh structure 202 themselves can make the flow velocity uniform and the pulsating flow even if the cross-sectional areas and the like are different. This is because smoothing can be achieved.

Furthermore, an inward wall surface of a straight line portion of the gas passage between the downstream outlet of the child pressure regulator 102 and the instantaneous flow rate measurement sensor 103 via the bypass gas flow passage 101 is formed. The friction coefficient is made uniform by polishing. In this way, the gas passage, that is, the bypass gas flow passage 101, the conduction passage 104, and the like are provided with conditions that allow the gas flow to flow uniformly, and the vortex and the deviation of the flow velocity of the gas flow flowing therethrough are adjusted. It is formed so that the above can be eliminated.

By the way, the labyrinth structure 2 according to the present invention
01 is parallel to the central axis of FIGS. 4 (a) and 4 (b) so that the gas flow does not pass through without resistance, but rather positively acts as a fluid resistance of the gas flow. As shown in the cross-sectional structure in the direction and the orthogonal direction,
Partition walls 501, 502, 503 as barriers to gas flow
Etc. are formed, and the gas flow 601 is strayed by these.

Further, in the mesh structure 202 as well, in the same manner as the labyrinth structure 201, the gas flow does not pass through without resistance, but rather positively becomes a fluid resistance of the gas flow. 4 (c) and 4 (d), which show a sectional structure and a planar structure in a direction orthogonal to the central axis thereof, have a moderate fluid resistance against the gas flow 601 such that the flow velocity loss is not substantially inconvenient. Thus, the mesh 504 is formed to eliminate the bias of the flow velocity distribution in the cross section of the gas flow 601. Further, the outer shell sleeve (cylindrical thick outer container) itself of the mesh structure 202 is formed so as to also serve as the ring-shaped fitting member according to the present invention, that portion, that is, the conduction path 1
The cross-sectional diameter near the gas inflow port to 04 is made uniform with the cross-sections before and after that.

For each of these structures, it is advisable to adopt a specification such that the fluid flow has an appropriate fluid resistance to the gas flow 601 and the flow rates of the gas flow 601 can be made uniform. That is, for quantitative specifications such as the mesh size of the mesh or the opening size and opening rate of the ventilation holes, the cross-sectional shape of the passage 101s through which the gas flow passes (a pipe shape is common, but not limited to this. Needless to say), the size of the cross section of the gas passage, the coefficient of friction of the wall surface of the passage, the overall length of the passage, etc. can be varied in various ways. Since description is practically impossible, the specification may be appropriately determined based on the qualitative method as described above.

In the gas leak detection apparatus according to the present invention, the main parts of which are configured as described above, the operation of detecting a gas leak and issuing an alarm is essentially the same as the conventional gas leak. The operation from detection to alarm may be the same. Rather, the conventional method is even more advantageous because it can be easily applied to the conventional gas supply system. Therefore, a description of such a part that may be the same as the conventional one will be briefly described, and in particular, gas leakage detection using the instantaneous flow rate measurement sensor 103, which is one of the features of the gas leakage detection device according to the present invention, will be described. The operation and the alarm generation operation when the gas leakage is detected will be mainly described based on the schematic configuration diagram of FIG. 5 and the schematic flowchart of FIG.

The instantaneous flow rate measurement sensor 103 is an instantaneous flow rate measurement sensor that measures the gas flow at each moment in a predetermined fixed cycle. That is, the instantaneous flow rate measurement sensor 103 measures various fluid-like physical quantities that change corresponding to the flow velocity of the gas flow, which is called a so-called estimation method (or an estimation method in literature), and the measurement is performed. A method that calculates the gas flow rate based on the value, that is, a pressure flow rate measurement method that measures the temporal change of the dynamic pressure or static pressure due to the gas flow, the differential pressure difference between the upstream and downstream of the gas flow, etc. Area flow rate measurement method to measure the viscous resistance of the turbine, turbine flow rate measurement method to measure the power of the gas flow to move the turbine blades, vortex flow rate measurement method to measure the frequency of the vortex generated in the gas flow, An ultrasonic flow rate measuring method in which ultrasonic waves are propagated to and the propagation time or propagation velocity thereof is measured is particularly suitable. Alternatively, a thermal mass flow rate measuring method in which a heating wire is arranged in a gas flow and a temperature change before and after the heating wire is measured can be preferably used. In the present embodiment, as a good example of the instantaneous flow rate measurement sensor 103, for example, Japanese Patent Publication No.
-43906 and other pressure sensors were used as a sensor main body for measuring the dynamic pressure of the gas flow, but an instantaneous flow rate measurement sensor was used. , For example, various types of sensors such as an eddy flow rate measurement method and an ultrasonic method can be used.

Instantaneous flow rate measuring sensor 103 as described above
Measures (monitors) the instantaneous gas flow rate ΔV each time (T) passes a predetermined constant period Tm (Y in s1 of FIG. 6) (s2). Subsequently, the gas leakage determination means 301 uses the measured instantaneous gas flow rate ΔV as a predetermined specific threshold flow rate V.
th, that is, a threshold flow rate VL ≦ ΔV ≦ Vth defined as a minute leak flow rate of, for example, 3 liters / hour or less to 0.5 liters / hour or more (s)
3). Here, it is needless to say that the above-mentioned VL is a numerical value that can be determined to be a non-zero minute flow rate. At this time, the measured instantaneous gas flow rate ΔV is outside the threshold flow rate range VL ≤ ΔV ≤ Vth, and in particular Vth
If the value exceeds, it is determined that the gas is in use. However, here, when the measured instantaneous gas flow rate ΔV is within the threshold flow rate range, it is determined that a minute flow rate is flowing, and the measurement time point is used as a starting point, for example, in advance for 30 days. Specified specific period Dth
The number of days (Dx) that such a minute flow rate was detected
Is counted (s4). However, here, during the counting of the number of days (Dx), the gas flow rate ΔV as indicated by N of s3 is the threshold flow rate range VL ≦ ΔV ≦ V.
When the value is out of th and the value at that time is less than VL (that is, when ΔV <VL), the count of the number of days until then is reset and the original value is returned to s1. This is because if, for example, a fire in a gas water heater was in use and it was about to be mistakenly detected as a minute gas leak, it would be immediately detected if the use was stopped. It goes without saying that the resetting as described above can prevent the malfunction as the detection of the minute gas leakage. The threshold flow rate range VL
Vth is a minute flow rate that flows only when a minute leak occurs, and the probability that such a minute gas flows will be close to 0, but not 0, during normal use of the gas as described above. That is, the gas flow is not completely stopped.) It is set within the range of the value of the minute flow rate.

When the count value Dx on the day when the minute flow rate is detected becomes equal to or greater than the period Dth (s
5 Y), the gas leakage determination means 301 determines that a slight leakage has occurred (s6). In response to this, the alarm means 302 issues an alarm to that effect (s7). When a gas leak is confirmed and the alarm is reset (s
8) Then, the apparatus returns to s1 (step 1) and starts the same operation as above. Note that the outline flowchart of FIG. 6 is drawn so that one endless loop is drawn as a whole and the operation is repeated, but this is compulsory, for example, when the replacement life of the device is reached, which is not shown. Needless to say, when the operation is stopped in the interrupt mode or the like, the stop operation can be performed. However, since the gas leakage detection device according to the present invention essentially repeats the above-described gas leakage detection function in an infinite loop shape without rest during its continuous use, regarding such trivial matters, ,
It is needless to say that the description is omitted for simplification of description and illustration.

[0053]

As is clear from the detailed description above, according to the present invention, in the switching type gas leakage detection device having the minute leakage detection device, the overall size of the device is reduced and the structure is simplified. Can be achieved, and while maintaining a very small error that has a large effect due to the minute flow rate detection,
It is possible to realize accurate and highly reliable detection of minute flow rate leaks. Furthermore, the problem that the drain of water or the like enters or adheres to the minute leak detection device is solved, and the flow rate sensor in the minute leak detection device is solved. It is possible to provide a switching type gas leak detection device equipped with a minute leak detection device, which has improved durability by preventing functional deterioration, corrosion or damage of various structures and the like.

[Brief description of drawings]

FIG. 1 is a diagram showing a main part of a configuration of a gas leakage detection device according to the present invention.

FIG. 2 is a diagram showing a schematic configuration of a main part of the entire gas supply system in which the gas leakage detection device according to the present invention is incorporated and used.

FIG. 3 shows a labyrinth structure 201 and a mesh structure 20.
2 and the instantaneous flow rate measurement sensor 103 in which they are used
It is a figure which shows the whole main internal structure.

FIG. 4 shows a labyrinth structure 201 and a mesh structure 20.
It is a figure which shows the structure of 2.

FIG. 5 is a diagram showing an outline of a configuration of each means for executing a gas leak detection operation and an alarm generation operation according to the present invention.

FIG. 6 is a schematic flowchart mainly showing an operation of gas leak detection using the instantaneous flow rate measurement sensor 103 and an alarm generation operation when a gas leak due to the gas leak detection is detected.

FIG. 7 is a diagram showing an outline of a configuration of a gas leakage detection device for detecting leakage of a gas supply pipe including a buried pipe of a conventional liquefied propane gas supply facility.

[Explanation of symbols]

1 ... LPG cylinder 4 ... Gas supply piping 100 ... Parent pressure regulator 101 ... Bypass gas flow path 102 ... Child pressure regulator 103 ... Instantaneous flow rate measurement sensor 104 ... Conducting path 105 ... Sensor body 201 ... Labyrinth structure 202 ... Mesh structure 203 ... Ring-shaped fitting member 301 ... Gas leakage determination means 302 ... Alarm means 401 ... Outer ring for fitting

Continuation of the front page (56) References JP-A-3-41300 (JP, A) Actually open 4-32021 (JP, U) Actually open 61-139429 (JP, U) (58) Fields investigated (Int .Cl. ⁷ , DB name) G01F 1/00-9/02

Claims (9)

(57) [Claims] 1. A parent pressure regulator provided in a gas supply pipe for communicating gas supplied from a gas supply source, and an inlet on an upstream side of the parent pressure regulator so as to bypass the parent pressure regulator. A bypass gas flow path, which is connected to an outlet on the downstream side, and a child pressure adjuster which is provided in the bypass gas flow path and is adjusted to a higher adjustment pressure than the adjustment pressure of the parent pressure adjuster, Arranged on the downstream side of the flow of the gas than the child pressure regulator in the bypass gas flow path, and providing gas flow rate measuring means for measuring the flow rate of the gas,
In a gas leak detection device capable of detecting that the gas is continuously flowing for a predetermined time by the gas flow rate measuring means and determining that a gas leak has occurred on the downstream side of the parent pressure regulator. The gas flow rate measuring means is provided with a conduction path for conducting gas, and the gas in the flow rate range up to the maximum value corresponding to the adjustment pressure of the child pressure regulator and the cross-sectional area of the conduction path in the conduction path. a gas flow rate measuring means using the instantaneous flow rate measurement sensor capable of measuring the instantaneous flow rate, the upstream side of the instantaneous flow rate measuring sensor in said conductive path, hydrodynamic respect to the flow of the gas in the conduits The resistance of a vertical component in the vertical cross section becomes a resistance, and the positional flow velocity distribution and the temporal pulse of the gas in the cross section of the conduction path become
A gas leakage detection device comprising a labyrinth structure for equalizing flow changes . 2. The gas leak detection device according to claim 1.
Between the instantaneous flow rate measuring sensor and the labyrinth structure
The fluid force against the gas flow in the conduit.
The resistance of the vertical cross-sectional direction component,
Positional Velocity Distribution and Temporal Pulsation Variation in the Cross Section
It is characterized by further including a mesh structure for uniformizing
Gas leak detection device to collect. 3. A gas leakage detection device according to claim 1 or 2, wherein the gas which is characterized in that child pressure regulator and the master pressure regulator and bypass gas flow path and by integrating the gas flow rate measuring means Leak detection device. 4. The gas leakage detection device according to any one of claims 1 to 3, wherein the parent pressure adjustment and the gas by the gas flow measuring means is detected that flows continuously a predetermined time Gas leakage determining means for determining that a gas leakage has occurred on the downstream side of the reactor, and when the gas leakage determining means determines that a gas leakage has occurred on the downstream side of the parent pressure regulator, the gas leakage And a warning means for warning at least one of a visual medium and an audible medium. 5. The gas leakage detection device according to claim 4 , wherein the child pressure regulator, the parent pressure regulator, the bypass gas flow path, the gas flow rate measuring means, the gas leakage determining means, and the alarm means are provided. Gas leakage detection device characterized by being integrated. The gas leakage detection device according to any one of 6. The method of claim 1 to 5, the conductive paths of at least the instantaneous flow rate measuring sensor from the downstream side outlet of the child pressure regulator through the bypass gas flow passage A gas leakage detection device, characterized in that the cross section of the gas passage up to the outlet is made uniform in size and shape. 7. The gas leakage detection device according to any one of claims 1 6, between the downstream outlet of the child pressure regulator to at least the instantaneous flow rate measuring sensor through the bypass gas flow passage 2. A gas leakage detection device, characterized in that the friction coefficient of the inward wall surface of at least a straight line portion of the gas passage is made constant. 8. The gas leakage detection device according to any one of claims 1 to 7, the labyrinth structure and the mesh structure, and characterized by being arranged removably relative to the conduction path Gas leak detector. 9. The gas leakage detection device according to claim 6 , wherein the member for forming the gas passage is fitted in a portion having a locally wide cross section, and the cross section of the gas passage has a constant dimension. And a ring-shaped fitting member that is uniform in shape and shape.