JP3071863B2 - Gas supply system leak monitoring method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas supply system leak monitoring method suitable for a gas supply system having a buried gas supply pipe.

[0002]

2. Description of the Related Art For example, a gas supply facility for supplying gas to a collective house such as an apartment is constructed as shown in FIG. In the figure, a gas supply source 1 such as a propane gas cylinder and a gas inlet 3 of an apartment 2 are connected by a gas supply pipe 4, and the gas supply pipe 4 has an original pressure regulator 5, a pressure regulator 6, and a gas flow rate. A meter 7 is provided. The gas inlet 3 is provided with, for example, valves 8 and 9 for each floor, and each house in the apartment 2 is connected to a gas consuming facility 13 by a pipe 12 through a valve 10 and an individual gas flow meter 11, respectively. Is supplied.

On the other hand, a portion 4a of the gas supply pipe 4 which is close to, for example, the condominium 2 is often buried underground because it is necessary to provide a passage or the like. Such a gas supply pipe 4 may be cracked by a load from the surface of the ground, and the pipe may be cracked by corrosion of the pipe, and there is a risk that gas may leak from the crack. Therefore, it is necessary to monitor gas leakage.

[0004] This gas monitoring method has conventionally been performed by the following method.

(1) A gas flow meter integrator of a gas flow meter, in which a worker goes to the site every day for about 30 days at a time when gas usage is the least in a day, for example, at night or late at night, and integrates the entire supply amount. A method of checking movement and comparing usage over night to see if there is any abnormality.

(2) There is a method in which the gas supply is temporarily stopped, the connection portion of the gas supply pipe 4 is disconnected, and pressurized air is introduced to perform an airtightness inspection.

However, the method (1) requires the worker to go to the site for 30 days and requires much labor. On the other hand, the gas flow meter which integrates a relatively large flow rate cannot detect the minute flow rate. It is difficult and the accuracy is very low.

Further, the method (2) has many problems, such as the time period for implementation is restricted, the operation is troublesome, and there is a risk of causing a serious accident when resuming use.

Accordingly, the present applicant has developed a leak monitoring system, which is an improved version of the method (1), on July 7, 1989, entitled "Leakage monitoring system for gas distribution device and gas supply pipe".
Filed as

[0010] This will be described in an embodiment to be described later, but the above-described conventional gas supply system is provided with a minute flow rate detecting means 15.

More specifically, as shown in a broken line in the conventional example of FIG. 6, the gas pressure meter 7 for integrating the amount of gas supplied to the entire condominium 2 with the original pressure regulator 5 on the gas cylinder 1 side. The gas supply pipe 4b has one pressure regulator,
That is, the first pressure regulator 6 is provided, and the minute flow rate detecting means 15 is provided with the bypass gas flow path 4c connecting the inlet side and the outlet side thereof, and the second pressure regulator 1
7 and a micro flow rate detection microcomputer meter 18 (hereinafter, referred to as a micro flow rate detection meter). This minute flow rate detection meter 18 has a minute flow rate, for example, 3
Flow rate of about l / h (liter / hour) can be accurately integrated.

The first pressure regulator 6 is controlled by the second
When the pressure of the gas supply pipe 4 is low in the daytime by setting the adjustment pressure of the pressure regulator 17 higher by, for example, 20 mmH ₂ O, the gas is supplied through both pressure regulators 6 and 17. When the amount decreases, the gas supply pipe 4
The internal pressure becomes high and eventually approaches the pressure of the second pressure regulator 17, the first pressure regulator 6 is closed, and all the supplied gas passes through the minute flow rate detection meter 18.

That is, when the flow rate becomes very small, such as at midnight to be measured, the flow is automatically switched to only the bypass flow path 4c, and enters the gas flow meter 7 through the minute flow rate detection meter 18. , Detect even small flow rates.

In the flow rate measurement by the minute flow rate detecting means 15, the minute flow rate detecting meter 18 detects and confirms the presence or absence of a gas flow during a time period when gas use is stopped at night and at midnight.

The method of detecting leakage of the minute flow rate detection meter 18 is that the flow rate every hour is continuously measured by the minute flow rate detection meter 18 not only at night and late at night, but also during normal daytime. (1) When the meter makes one or more rotations per hour (when a flow rate of 3 l / h or more is detected) for about 720 hours (30 days) continuously, it is warned that there is a possibility of minute leakage. Is what you do. FIG.
As shown in FIG.

(2) Also, if there is a time zone in which the meter does not make one rotation or more even for one hour during the elapse of 720 hours, it is determined that there is no minute flow rate (leakage), no alarm is issued, the measurement timer for 720 hours is cleared, and the flow rate is continued. It measures the change. The result is as shown in FIG.

According to this system, the micro flow rate detection meter 18 automatically measures the flow rate and determines whether or not there is a leak by the microcomputer logic, which is excellent in that labor is remarkably saved. In a large-scale gas supply system, a facility in which the use of gas is not stopped at all for one month may be considered. In some cases, the pilot burner of any combustor is ignited for one month continuously.

Furthermore, the gas piping becomes longer and more complicated, and the flow rate may exceed 3 l / h in a total of very few dangerous leaks at a few places. In such a case, all are erroneously determined to be suspected of leakage.

Therefore, according to another leak detection method,
It is necessary to check whether or not the gas supply pipe has leaked, which may lead to unnecessary labor and expense.

[0020]

As described above, in the conventional gas supply system leak monitoring method, even if a small flow rate is detected, it is determined that there is a leak. However, even when there is no danger, the inspection is performed by another method, and there is a possibility that wasteful expenses may be incurred.

The present invention has been made in order to prevent the occurrence of the above-described undesired situation, and has as its object to provide a leak monitoring method for a gas supply system which is practical.

[0022]

In order to achieve the above object, according to the present invention, a gas from a gas source is supplied to a gas flow source.
Gas supply to the combustion device via the
This is a method of monitoring the leakage of the
Set multiple levels of flow based on flow and
Continuous or intermittent within the set time for leak monitoring
The flow rate per unit time by the gas flow meter
Flow rate detection
Output method and the flow rate level detection method
Elapsed time measuring means provided for multiple levels of flow
Operating all stages simultaneously with the start of the set time and
This detected flow rate for each flow level detection during the course of the process
Cancel the elapsed time of the flow level above the level.
The minimum flow level detection method to start measuring from the time of
At the end of the set time, the elapsed time reaches the set time
Alarm level based on the highest flow level
And an alarm level test method for determining the alarm level .

[0023]

[0024]

[0025]

According to the first aspect of the present invention, since the minimum flow rate during the set time for leak monitoring is detected, the degree of leak can be grasped, and the actual situation is considered in consideration of the risk to the gas supply scale. Appropriate measures can be taken. Also,
Since the elapsed time of the elapsed time measuring means corresponding to the flow level higher than the flow level detected during the elapse of the set time is cleared, the lowest one of the detected flow levels reaches the set time. , And the flow level can be grasped reliably.

[0026]

[0027]

[0028]

[0029]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the present invention will be described below with reference to FIGS.

First, an outline of the method of the present invention will be described, then a gas supply system provided with an apparatus for performing the method will be described, and the operation of the method of the present invention will be described with reference to flowcharts.

FIG. 1 is an overall configuration diagram of a gas supply system, FIG. 2 is a block diagram of a control system, and FIG. 3 is an explanatory diagram of an alarm level divided according to a flow rate set based on a flow rate. FIG. 4 is a flowchart illustrating an embodiment of the method of the present invention, and FIG. 5 is an overall configuration diagram of another gas supply system embodying the present invention.

The set time for monitoring, the flow rate level and the alarm level in the method of the present invention will be described as an example in the case of this embodiment.

The set time may be appropriately set according to the actual situation, but is 720 hours (30 days) in this embodiment.

In this embodiment, the flow level is divided into four stages, and the alarm level is divided into four stages corresponding to the minimum flow level detected during the set time. Become like In other words, (flow rate) (flow rate level) (alarm level) If less than 3 l / h Safe flow level Safety level 1 light ON 3 or more and less than 10 l / h 1-stage flow level 1-level alarm 2 light ON 10 or more 50 l / h If it is lower than 2 steps flow level 2 steps alarm 3 lights ON 50l / h or more 3 steps flow level 3 steps alarm 4 lights ON, and Fig. 3 shows this in a graph. The horizontal axis represents the distribution of the flow level detected within the set time, and the vertical axis represents the flow level. From the left end, the first group shows the case of the safety level, the second group shows the case of the one-stage alarm, the third group shows the case of the two-stage alarm, and the fourth group shows the case of the three-stage alarm.

The lighting of the alarm level will be described later.

Next, the gas supply system comprises a gas supply system main unit A, a minute flow rate detecting means 15, a minimum flow level detecting means 31, an alarm means 41 and the like.

Since the supply system body A in FIG. 1 has the same configuration as the conventional example shown in FIG. 6, the same portions are denoted by the same reference numerals and detailed description thereof will be omitted.

The minute flow rate detecting means 15 is provided with a bypass flow path 4c having both ends connected to the inlet side and the outlet side of the first pressure regulator 6, as outlined in the conventional example of FIG. A valve 16, the other pressure regulator, that is, a second pressure regulator 17, a minute flow rate detection meter 18, and a valve 19 are sequentially provided in the flow path 4 c from the inlet side. And the second
The adjustment pressure of the pressure regulator 17 is set higher than the adjustment pressure of the first pressure regulator 6. For example, the first pressure regulator 6
Is set to 280 mmH ₂ O,
Adjusting the pressure of the second pressure regulator 17 so as to set to about 300mmH ₂ O.

The minute flow rate detection meter 18 is
1. An integrating meter having a built-in microcomputer 20 having a storage unit 22 (ROM 22a, RAM 22b), a calculation unit, and the like.
A flow rate sensor 24 for detecting the rotation of the weighing section is connected to the CPU 21, and both constitute a flow rate detecting means 25.
The flow for each hour is sequentially output as a detection signal by the calculation of the PU. In addition, as described above, the minute flow rate,
For example, a flow rate of about 3 l / h (3 liters / hour) can be accurately integrated.

By setting the adjustment pressure as described above, the minute flow rate detection means 15 adjusts the pressure regulators 6 and 17 during the time period when the gas usage is small at night, for example, between 22:00 and 4:00. Since the first pressure regulator 6 is closed by the differential pressure, if there is a minute flow, the gas flow is automatically switched to only the bypass flow path 4c, and the flow is detected by the flow detecting means 25 of the minute flow detecting meter 18. It is reliably detected.

When the gas consumption is large and the pressure is low as in the daytime, the gas is supplied through both pressure regulators 6 and 17.

The minimum flow level detecting means 31 determines whether
PU 21 and three timers T ₁ and T connected thereto
₂ , T _3, and a reset switch 32.

The timer T ₁ is provided corresponding to the first-stage flow level, T ₂ is provided corresponding to the second-stage flow level, and T ₃ is provided corresponding to the third-stage flow level.
These are controlled by the CPU and start operating at the same time as the start of the set time. For example, if a three-stage flow rate level (50 l / h or more) is detected during the course of the process, all the timers are activated.
Although it continues the elapsed time measurement, when it is detected two-stage flow level (less than 10l / h or 50 l / h) is, the timer T ₃ corresponding to the three-stage flow level stage of the flow level higher than the clear Then, a new measurement is started from this point, and the timers T1 and T2 continue the measurement as they are.

If the first-stage flow level or the safe flow level is not detected as it is, the timers T ₂ and T _2
1 continues to run and stops at 720 hours. As a result, it is detected that the minimum flow level until the end of the set time is the two-stage flow level, and is determined as the two-stage alarm level.

If a safe flow level is detected during the course of the process, all timers T ₁ , T ₂ and T ₃ are cleared.

The alarming means 41 comprises a CPU 21, an alarming circuit 42 connected thereto, and a communication circuit 4 connected thereto.
3 is provided. The alarm circuit 42 has four LEDs 1 to L
ED4 are connected, and these are provided in the minute flow rate detection meter 18.

After completion of the set time (720 hours),
In the case of the safety level, LED1 is turned on. In the case of the one-stage alarm, LED2 is turned on. In the case of the two-stage alarm and the three-stage alarm, LED3 and LED4 are turned on, respectively, and the alarm level of the monitoring result is displayed.

The communication circuit 43 communicates flow rate information, alarm information and other information to the management center via the NTT line.

The gas supply system implementing the method of the present invention is configured as described above. Next, an embodiment of the method of the present invention will be described with reference to the flowchart of FIG.

[0050] First of all, when you start, initial setting is made in step P _1. Clear data in RAM and turn off each alarm.

[0051] or not the reset switch 32 in step P ₂ is either ON is determined, in the case of YES back to step P _1, if NO, the process goes to step P _3.

In step P _3, it is determined whether or not the flow rate there is, the flag F ₁ in the case of NO in step P _4, F _2,
To F ₃ put a 0.

[0053] timer T ₁ in step P _5, T _2, T ₃
Was clear, returns to the step P _2, this time because the reset switch 32 is OFF, again goes to the step P _3.

[0054] and is now in the step P ₃ is that there is a flow rate Y
ES, and the flow rate per hour is calculated in step P _6.

[0055] whether the flow rate ≧ 50 l / h in step P ₁₁ is determined and when YES, and the flag F ₃ in step P ₁₂ =
1 whether or not is determined, NO because, F ₃ in step P ₁₃
1 is entered, the timer T ₃ is started in step P ₁₄ in.

[0056] In the step P ₂₁ flow rate ≧ 10l / h, so Y
ES next, NO is whether In step P ₂₂ F ₂ = 1
Next, 1 enters the F ₂ In step P _23, Step P
Timer T ₂ is started at _24.

[0057] is determined whether the flow rate ≧ 3l / h in step P ₃₁ is, it is determined whether F ₁ = 1 is YES because the step P _32, F ₁ to 1 enters in NO since the step P _33, step timer T ₁ is started to return to the step P ₂ in P _34.

[0058] When following the flow level is to dropped to 5l / h (1-stage flow level), is NO in step P _11,
In step P ₁₇ F ₃ 0 enters the timer T ₃ is clear, is NO in step P _21, in step P ₂₇ F
₂ 0 enters the timer T ₂ is clear, YES next step P _31, F ₁ is because 1 in step P _32, YES, and the in step P ₃₅ the timer T ₁ is 72
It is determined whether or becomes 0 hours, because not yet reached, NO, and the flow returns to step P _2.

In this state, the minimum flow level of the detected flow level at the time of halfway is currently the first-stage flow level. So, assuming that the set time of 720 hours has elapsed,
Timer T ₁ is stopped in step P _36, becomes one stage alarm, alarm lamp LED2 is lit, 1-stage alarm is displayed and reported to the management center.

This is the end of the description of this embodiment.

Next, another embodiment is shown in FIG. This is almost the same configuration as the first embodiment. The difference is that the gas flow meter 7 in the above embodiment is not provided in this embodiment. This is suitable for the case where the scale is small, and the others are the same as those of the above-described embodiment. Therefore, the same portions are denoted by the same reference numerals and detailed description will be omitted.

Although the description of both embodiments has been completed above, the monitoring set time is not limited to 720 hours, and may be set to an appropriate time. Further, the stage of the flow rate level and the stage of the alarm level are not limited to the classification of the embodiment, and may be set according to the scale of the gas supply system.

Although the case of propane gas has been described as an example, it goes without saying that the case of city gas may be used. Furthermore, the number of timers may be determined according to the target flow level.

[0064]

As described above in detail, according to the first aspect of the present invention, it is possible to not only know the presence or absence of a leak but also appropriately grasp the degree of caution based on the minimum flow rate value.
Since the alarm level is determined, appropriate measures can be taken in accordance with the size of the supply system, and an undesirable situation can be prevented. In addition, since the elapsed time of the elapsed time measuring means corresponding to the flow rate level higher than the flow rate level detected during the middle of the set time is cleared, the lowest flow rate level among the detected flow rate levels reaches the set time. Therefore, the flow rate (leakage) level can be reliably grasped. Furthermore, since the alarm level is determined after the set time by the alarm level determination method, appropriate measures can be taken reliably based on the result of the alarm level, and unnecessary labor and expenses can be prevented. it can.

[0065]

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a gas supply system implementing a method of the present invention.

FIG. 2 is a block diagram of a control system of the gas supply system.

FIG. 3 is a graph illustrating an alarm level setting in the embodiment of the present invention.

FIG. 4 is a flowchart for explaining the embodiment.

FIG. 5 is a configuration diagram of another gas supply system for the embodiment.

FIG. 6 is a configuration diagram of a gas supply system for explaining a conventional example.

FIG. 7 is an explanatory diagram of a conventional leak detection method.

[Explanation of symbols]

 T1, T2, T3 Timer 1 Gas supply source 4, 4a, 4b, 4c Gas supply pipe 7, 18 Gas flow meter 12 Combustion device 21 CPU 31 Elapsed time detecting means

Continuation of the front page (56) References JP-A-63-150512 (JP, A) JP-A-63-153317 (JP, A) JP-A-59-121300 (JP, A) JP-A-62-147338 (JP) , A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G01M 3/00-3/40

Claims (1)

(57) [Claims] A gas from a gas supply source is measured by a gas flow rate meter.
Gas supply system to be supplied to the combustion device via the
A system for monitoring system leaks, in which there are multiple levels of flow levels based on the flow per unit time.
Within the set time for leak monitoring.
Continuous or intermittent unit time measurement with the gas flow meter
Measures the flow rate per interval and detects the flow level during the course
Flow level detection method and the flow level detection method
Provided corresponding to the plurality of flow rate levels set by
All elapsed time measuring means at the same time as the start of the set time
Activate each time the flow level is detected during the
Elapsed flow level above the detected flow level
Cancel the time and start measuring from this point.
Bell detection method and elapsed time at the end of the set time
Is the highest flow level that has reached the set time.
Based on the warning level verification method that determines the warning level based on
A method for monitoring leakage of a gas supply system, the method comprising: