JP6284820B2 - Gas shut-off device - Google Patents

Description

  The present invention relates to a gas shut-off device that detects the presence or absence of internal pipe leakage.

  Conventionally, by using an average value for the number of determinations of the section average flow rate by the section calculation means, it is possible to stably determine that there is no flow even under pulsation, and pulsation due to the use of a gas engine, heat pump, air conditioner, etc. A gas shut-off device is disclosed that prevents an erroneous determination that an inner pipe leakage warning is generated even in an environment in which there is no actual leakage even in an environment in which a leak occurs (for example, patents) Reference 1).

  Further, when the flow rate based on the flow rate signal from the flow rate sensor is greater than a predetermined determination value and is greater than the predetermined determination value for a predetermined time or more, it is determined that there is an inner pipe leak, and the shut-off valve is Drive to shut off the gas flow path. Since the flow sensor is located on the downstream side of the shut-off valve, when the gas flow is shut off by the shut-off valve, the flow rate flowing into the flow sensor becomes zero. At this time, if the inner pipe leaks, the gas remaining in the blocked inner pipe leaks and the gas pressure decreases. On the other hand, when the gas pressure does not decrease, the flow rate flowing into the flow rate sensor is zero, so that the zero flow rate value of the flow rate sensor can be determined. In this case, if the flow rate value based on the flow rate signal from the flow rate sensor does not become zero, it is determined that there is an abnormality in the flow rate sensor. For this reason, since the abnormality by the secular change etc. of a flow sensor can be judged, the gas meter which can improve the misjudgment of an inner pipe leak is disclosed (for example, patent document 2).

JP 2010-216724 A JP 2004-219259 A

  However, in the conventional gas shut-off device disclosed in Patent Document 1 and the gas meter disclosed in Patent Document 2, there is no gas leakage in the gas pipe, and the gas pipe capacity (particularly in an unused state in which no gas flows in the gas pipe) In large-capacity piping for business use, etc., gas flow (forward flow or reverse flow) occurs over a long period of time due to temperature change (rise / decrease), etc. (hereinafter referred to as breathing motion), and internal pipe leakage There was a problem that a warning may occur.

  This invention solves the said conventional subject, and it aims at providing the gas interruption | blocking apparatus which can suppress the misjudgment of an inner pipe | tube leak.

  In order to solve the above-described conventional problems, a gas shut-off device according to the present invention is connected to a gas supply pipe and measures flow rate measuring means for measuring a gas flow rate at regular time intervals, and calculation means for obtaining a flow rate value by the flow rate measuring means. Section calculation means for accumulating a flow rate value calculated by the calculation means for a predetermined time to calculate a section average flow rate and obtaining a maximum flow rate and a minimum flow rate therebetween, and whether there is a gas flow rate based on the flow rate from the section calculation means A flow rate presence / absence determination means, a pressure sensor for detecting the pressure in the gas supply pipe, and a pressure determination means for inputting a pressure value from the pressure sensor and determining a pressure value, If the section average flow rate is within the judgment allowable range and the pressure value by the pressure judgment means is within the judgment range, the section level when the section computation value from the section computation means is within the judgment range is shown. The flow rate is accumulated to calculate the average flow rate, and when the calculated average flow rate is within the average determination flow rate, it is determined that there is no flow rate, and when the calculated average flow rate is other than the average determination flow rate, it is determined that there is a flow rate. .

  By using the gas shut-off device of the present invention, it is possible to reduce the occurrence of an inner pipe leak warning due to breathing operation or the like even though it is not actually leaking.

The block diagram of the gas meter in Embodiment 1 of this invention. The schematic block diagram of the ultrasonic flow measurement means. The characteristic view which shows the change of the gas flow rate. The figure which shows the determination threshold value of the same area average flow volume. The flowchart which shows the operation | movement procedure of the same flow amount presence determination. The flowchart which shows the operation | movement procedure of the flow volume presence determination in Embodiment 2 of this invention. The schematic block diagram of the ultrasonic flow measurement means.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The present invention is not limited to the embodiment.

  According to a first aspect of the present invention, there is provided a flow rate measuring unit that is connected to a gas supply pipe and measures a gas flow rate at regular time intervals, a calculation unit that obtains a flow rate value by the flow rate measurement unit, and a flow rate value calculated by the calculation unit. Section calculation means for calculating a section average flow rate by accumulating for a predetermined time and obtaining a maximum flow rate and a minimum flow rate therebetween, a flow rate presence / absence determination means for determining the presence or absence of a gas flow rate based on the flow rate from the section calculation means, and a gas supply pipe A pressure sensor that detects the pressure of the pressure sensor, and a pressure determination unit that inputs a pressure value from the pressure sensor and determines the pressure value, and the flow rate presence / absence determination unit has a section average flow rate within a determination allowable range, and If the pressure value by the pressure determination means is within the determination range, the average flow is calculated by accumulating the section average flow when the section calculation value from the section calculation means is within the determination range. With average flow rate is determined to no flow when less than the average determined flow rate, when the average flow rate calculated is other than average determination flow is to determine that there is flow.

  In particular, according to a second invention, in the first invention, a pressure value is taken in from the pressure determining means in accordance with an interval at which the section calculating means calculates a section average flow rate, and a difference between a maximum value and a minimum value of the pressure values is obtained. Section pressure determining means for determining whether or not is within the determination range, and the section calculation means is within the determination range if the difference between the maximum value and the minimum value of the pressure values taken in by the section pressure determination means The section average flow rate is accumulated, and if it is outside the determination range, the section average flow rate is not accumulated.

(Embodiment 1)
A gas meter will be described as a gas cutoff device in the first embodiment of the present invention. FIG. 1 is a block diagram of a gas meter according to a first embodiment of the present invention.

  In FIG. 1, a gas meter 1 is provided in the middle of a gas supply pipe a, and one or more gas appliances (not shown) installed in customer premises are connected to the downstream side of the gas supply pipe a. Yes.

  In FIG. 1, the gas meter 1 includes an interruption means 2, a flow rate measurement means 3, a display 4, a seismometer 5, a calculation means 6, a section calculation means 8, a flow rate presence / absence determination means 9, and a control means 10. The A flow rate measuring means 3 is provided on the downstream side of the shut-off device 2.

  The flow rate measuring means 3 is connected in the path of the gas supply pipe a and, as will be described later, obtains a propagation time difference caused by the gas flow in the gas supply pipe a by using an ultrasonic signal, and detects an instantaneous gas flow rate. Is.

  The calculation means 6 calculates the gas flow rate (flow rate value) by integrating the instantaneous flow rates based on the instantaneous flow rates detected by the flow rate measurement means 3. The flow rate measurement means 3 and the calculation means 6 realize the function of the flow rate measurement unit.

  The interval calculation means 8 accumulates the flow rate value calculated by the calculation means 6 for a predetermined time to calculate the interval average flow rate.

  The flow rate presence / absence determination unit 9 performs flow rate presence / absence determination processing for determining inner pipe leakage from the maximum flow rate and the minimum flow rate of the section average flow rate by the section calculation unit 8 every predetermined time.

  In addition to controlling the operation of each part in the gas meter 1, the control means 10 performs a flow rate determination result by the flow rate determination means 9, a warning due to the inner pipe leakage confirmation, a safety process such as gas shutoff, and the like.

  Here, the control means 10, the calculation means 6, the section calculation means 8, and the flow rate presence / absence determination means 9 are constituted by a processor and an operation program constituting a microcomputer (microcomputer) and the like, and the processor executes a predetermined operation program. Each function is realized by performing corresponding processing.

  The flow rate measurement means 3 in the first embodiment uses ultrasonic measurement means. However, as a measurement method, other flow measurement methods may be used in a short cycle such as a fluidic method. Other methods capable of continuous measurement may be used.

  The display 4 is composed of an LED, a liquid crystal display, and the like, and displays a gas flow rate, an operating state of the gas appliance, a warning, and the like. The seismoscope 5 detects vibration such as an earthquake and outputs a detection signal to the control means 10. The shut-off means 2 is connected to the path of the gas supply pipe a, and shuts off the gas supply by closing the gas supply pipe a based on an instruction from the control means 10. The pressure sensor 12 is connected to the gas meter 1 and measures the pressure in the path of the gas supply pipe a. The pressure determination unit 13 is a unit that periodically determines the pressure value measured by the pressure sensor 12.

  The operations of the flow rate measuring means 3 and the calculating means 6 will be described in detail below. FIG. 2 is a schematic configuration diagram of the flow rate measuring means 3.

  The flow rate measuring means 3 has a measurement flow path 30 having a rectangular cross section communicating with the gas supply pipe a, and a pair of ultrasonic waves is provided on the upstream side and the downstream side of the flow path walls facing each other. Transceivers 31 and 32 are arranged. These ultrasonic transmitters / receivers 31 and 32 are set so that the ultrasonic propagation path obliquely crosses the gas flow flowing through the measurement flow path 30, and the ultrasonic waves are alternately transmitted / received, so that the ultrasonic flow is sequentially transmitted and received. Ultrasonic waves are propagated in the opposite direction.

  At this time, the distance between the ultrasonic transmitters / receivers 31 and 32, that is, the measurement distance is L, the angle of the ultrasonic propagation path with respect to the gas flow is φ, and the ultrasonic wave from the ultrasonic transmitter / receiver 31 to the ultrasonic transmitter / receiver 32 downstream thereof. Assuming that the sound wave propagation time is t1, the ultrasonic wave propagation time from the ultrasonic wave transmitter / receiver 32 to the ultrasonic wave transmitter / receiver 31 upstream thereof is t2, and the sound velocity is C, the flow velocity V is obtained by the following equation.

V = L / 2 cos ((1/1/1)-(1 / t2))
The instantaneous flow rate of the gas flow is calculated from the flow velocity V and the cross-sectional area of the measurement channel 30. The time interval for measuring the instantaneous flow rate can be set within a range where ultrasonic waves can be transmitted and received.

  In general, since the start time and the time during which the gas flow rate changes due to control differ depending on the gas appliance to be used, reducing the measurement time interval is advantageous in order to instantaneously discriminate the appliance. However, as the measurement time interval is shortened, battery consumption increases in a gas meter or the like driven by the battery. Further, when the measurement time interval is a two-digit order interval equivalent to the membrane type used in the conventional gas meter, it becomes difficult to judge by looking at the difference in flow rate change.

  In this embodiment, when the gas appliance is not used, the periodic instantaneous flow rate is measured at intervals of 2 seconds and the difference value is taken to determine the activation of the gas appliance. Note that the measurement time interval can be further shortened. For example, after starting the gas appliance, control such as shortening the measurement time interval may be performed in order to increase measurement accuracy.

  Next, the operation of the flow rate presence / absence determining means 9 will be described in detail below. FIG. 3 is a characteristic diagram showing a change in gas flow rate during pulsation, and FIG. 4 is a diagram showing an allowable determination range of the section average flow rate Qt.

  FIG. 3 shows an instantaneous flow rate value of the gas measured by the flow rate measuring means 3. If the instantaneous flow rate is stable near zero when the gas appliance is not in use, it is easy to determine that there is no flow rate, and if the instantaneous flow rate is stable at a minute flow rate, it is also easy to detect inner pipe leakage. .

  However, if there is a flow rate due to the effects of breathing, etc., it cannot be determined that there is no flow rate. There was a problem.

  When gas flow is generated due to breathing action, the pressure fluctuation is large, so when making a judgment of no flow rate, if the pressure value in the gas pipe is within the predetermined range, the section average for the predetermined time The maximum value (maximum flow rate) Qtmax, the minimum value (minimum flow rate) Qtmin and the average value (average flow rate) of the flow rate Qt are obtained and used for the determination of the degree of stability.

  FIG. 4 shows threshold values for determining the degree of stability of the section average flow rate Qt. Assuming that the average determination flow rate is Qh (L / h), a range from −Qh to Qh is a determination threshold (determination allowable range). If the section average flow rate Qt is outside the range of -Qh to Qh, it is determined that there is a flow rate. FIG. 4 shows the first determination count of the section average flow rate Qt that falls within the range of −Qh to Qh, which is the determination threshold. If the average flow rate of the section average flow rate Qt for the first determination count is out of the allowable determination range, it is determined that there is a flow rate.

  FIG. 5 is a flowchart showing an operation procedure of the flow rate presence / absence determination 9 in the present embodiment. The flow rate presence / absence determining means 9 stores a program for executing the control flow from step S1 to step S20 shown in FIG.

  In step S1, it is determined whether or not a predetermined time has elapsed. If the predetermined time has elapsed, the process proceeds to step S2. In step S2, it is determined whether or not the pressure value from the pressure determination means 13 is within a predetermined range. If it is not within the predetermined range, the process proceeds to step S6 without using the section average flow rate Qt. If the pressure value is within the predetermined range in step S2, the section average flow rate Qt is updated in step S3. In step S4, it is determined whether or not the section average value Qt is the maximum value (whether the section average value Qt is larger than the existing section average maximum value Qtmax). If it is the maximum value, the process proceeds to step S10, and the section average maximum value is determined. Update Qtmax. If the section average value Qt is not the maximum value in step S4, it is determined in step S5 whether the section average value Qt is the minimum value Qtmin (whether the section average value Qt is smaller than the existing section average maximum value Qtmin). If it is a value, the process proceeds to step S11, and the section average maximum value Qtmin is updated.

  In step S6, it is determined whether or not the difference between the maximum flow rate Qtmax and the minimum flow rate Qtmin from the section calculation means 8 is less than the allowable range width, and if not, the process proceeds to step S8. In step S7, it is determined whether or not the section average flow rate Qt from the section calculation means 8 is within the determination allowable range, and if it is within the determination allowable range, the process proceeds to step S13. In step S7, if the section average flow rate Qt is outside the allowable determination range, it is determined that there is a flow rate, the process proceeds to step S8, the inner pipe leakage determination timer is increased in step S8, and the inner pipe is determined in step S9. It is determined whether or not the leakage determination timer has reached a predetermined value. When the leakage determination timer reaches the predetermined value, the process proceeds to step S12 to determine the inner pipe leakage.

  In step S7, if the section average flow rate Qt from the section calculation means 8 is within the allowable determination range, in step S13, the section average flow rate Qt from the section calculation means 8 is added to the total flow rate. Increase the counter. In step S15, it is determined whether or not the continuous number counter has reached the first determination number. If so, the continuous number counter is cleared in step S16, and in step S17, the section average flow rate Qt is determined in step S13. The average flow rate is calculated using the total flow rate obtained by integrating the first determination times, and the total flow rate is cleared in step S18.

  In step S19, it is determined whether or not the absolute value of the average flow rate calculated in step S17 is within the average determination flow rate. If it is within the average determination flow rate, the flow proceeds to step S20 as no flow rate, and in step S20 the inner pipe leakage Clear the judgment timer. In step S19, if the absolute value of the average flow rate is not within the average determination flow rate, the process proceeds to step S8.

  In this way, the flow rate presence / absence determining means 9 determines the section calculated value from the section calculating means 8 if the section average flow rate Qt is within the determination allowable range and the pressure value by the pressure determining means 13 is within the determination range. If it is within the range, the average flow rate is calculated by accumulating the section average flow rate. If the calculated average flow rate is within the average judgment flow rate, it is determined that there is no flow rate, and the calculated average flow rate is other than the average judgment flow rate. Is to determine that there is a flow rate.

  As described above, in the present embodiment, it is possible to stably determine that there is no flow rate even when breathing motion is occurring by determining the section average value and the pressure value, and to give an erroneous warning of inner pipe leakage. Can be prevented.

(Embodiment 2)
A gas shut-off device according to the second embodiment of the present invention will be described using a gas meter.

  FIG. 7 is a block diagram of a gas meter according to the second embodiment of the present invention. FIG. 6 is a flowchart showing an operation procedure for determining whether or not there is a flow rate in the present embodiment.

  In FIG. 7, the section pressure determination means 14 stores the maximum value and the minimum value of the pressure values measured at regular intervals in synchronization with the section calculation means 8 calculating the section average flow rate. Is determined and transmitted to the flow rate presence / absence determining means. The flow rate presence / absence determining means 9 stores a program for executing the control flow from step S29 to step S48 shown in FIG.

  In the flowchart shown in FIG. 6, it is determined in step S31 whether or not a predetermined time has elapsed. If the predetermined time has elapsed, the maximum and minimum value of the section pressure value from the section pressure determination means 14 in step S32. It is determined whether the difference from the value is within a predetermined range. If the difference is not within the predetermined range, the process proceeds to step S36 without using the section average flow rate Qt.

  In step S32, if the difference between the maximum value and the minimum value of the section pressure value is within a predetermined range, the section average flow rate Qt is updated in step S33. In step S34, it is determined whether or not the section average value Qt is the maximum value (whether the section average value Qt is larger than the existing section average maximum value Qtmax). If it is the maximum value, the section average maximum value Qtmax is determined in step S29. Update.

  In step S35, it is determined whether or not the section average value Qt is the minimum value (whether the section average value Qt is smaller than the existing section average maximum value Qtmin). If the section average value Qt is the minimum value, the section average maximum value Qtmin is set in step S30. Update. In step S36, it is determined whether or not the difference between the maximum flow rate Qtmax and the minimum flow rate Qtmin from the section calculation means 8 is less than the allowable range width, and if not, the process proceeds to step S38.

  If the difference between the maximum flow rate Qtmax and the minimum flow rate Qtmin is less than the allowable range in step S36, it is determined in step S37 whether or not the section average flow rate Qt from the section calculation means 8 is within the determination allowable range. If it is within the range, the process proceeds to step S41.

  In step S37, if the section average flow rate Qt is outside the allowable determination range, in step S38, the inner pipe leakage determination timer is increased with the flow rate, and in step S39, whether the inner pipe leakage determination timer has reached a predetermined value. If the predetermined value is reached, the inner pipe leakage is confirmed in step S40.

  In step S41, the section average flow rate Qt from the section calculation means 8 is added to the total flow, and in step S42, the continuous number counter is increased. In step S43, it is determined whether or not the continuous number counter has reached the first determination number. If reached, the continuous number counter is cleared in step S44. In step S45, the first of the section average flow rate Qt is determined in step S41. The average flow rate is calculated using the total flow rate obtained by integrating the determination times, and the total flow rate is cleared in step S46. In step S47, it is determined whether or not the absolute value of the average flow rate calculated in step S45 is within the average determination flow rate. If it is within the average determination flow rate, the flow rate is determined to be absent, and in step S48, the inner pipe leakage determination timer is cleared.

  As described above, in the present embodiment, it is possible to stably determine that there is no flow rate even when breathing motion is occurring by determining the section average value and the section pressure value, and it is possible to give an erroneous warning of inner pipe leakage. Can be prevented.

  As described above, the gas shutoff device according to the present invention can determine the leakage of the inner pipe even in an environment where pulsation or breathing motion is occurring. Applicable.

DESCRIPTION OF SYMBOLS 1 Gas meter 2 Blocking means 3 Flow rate measuring means 4 Display (display part)
DESCRIPTION OF SYMBOLS 5 Seismic device 6 Calculation means 8 Section calculation means 9 Flow existence determination means 10 Control means 12 Pressure sensor 13 Pressure determination means 14 Section pressure determination means

Claims (2)

A flow rate measuring means connected to the gas supply pipe for measuring the gas flow rate at regular time intervals, a calculation means for obtaining a flow rate value by the flow rate measurement means, and a section for accumulating the flow rate value calculated by the calculation means for a predetermined time Interval calculation means for calculating the average flow rate and obtaining the maximum flow rate and minimum flow rate therebetween, flow rate presence / absence determination means for determining the presence or absence of the gas flow rate based on the flow rate from the interval calculation means, and pressure for detecting the pressure in the gas supply pipe A sensor, and pressure determining means for inputting the pressure value from the pressure sensor and determining the pressure value,
The flow rate presence / absence determining means is configured such that when the section average flow rate is within the determination allowable range and the pressure value by the pressure determining means is within the determination range, the section calculated value from the section calculating means is within the determination range. The average flow rate is calculated by accumulating the section average flow rate, and when the calculated average flow rate is within the average judgment flow rate, it is determined that there is no flow rate. A gas shut-off device characterized by. Section pressure determination in which the section calculation means takes in the pressure value from the pressure determination means in accordance with the interval at which the section average flow rate is calculated, and determines whether the difference between the maximum value and the minimum value is within the determination range. The section calculation means accumulates the section average flow rate if the difference between the maximum value and the minimum value of the pressure values taken in by the section pressure determination means is within the determination range, and if the difference is outside the determination range The gas shut-off device according to claim 1, wherein the section average flow rate is not accumulated.