JPS6137175A - Gas machinery monitor and control system - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of the Invention) The present invention relates to a gas appliance monitoring and control system that centrally controls a large number of gas appliances from a central operation panel via a plurality of terminals, and particularly relates to a gas appliance monitoring and control system that controls a large number of gas appliances from a central operation panel through a plurality of terminals. This invention relates to a gas equipment monitoring and control system that has a gas leak detection function without causing any problems.

(Background of the Invention) Conventionally, a plurality of terminals to which one or more gas equipment loads, gas leak sensors, temperature sensors, etc. are connected are connected to a central operation panel via transmission lines, and these gas equipment loads are connected to each other via transmission lines. A gas appliance monitoring and control system is known that aims to save labor and energy in management by centrally monitoring and controlling the operation from a central operation panel. Such gas equipment monitoring and control systems are used, for example, to centrally monitor and control gas heating in each classroom in a school, etc. from a central operation panel installed in a staff room, etc., and also to perform detailed time schedule control, etc. By doing so, we aim to save energy.

By the way, it is desirable to add a gas leak detection device to such a gas equipment monitoring and control device to further improve safety, but it is preferable to add a gas leak detection device to such a gas equipment monitoring and control device. The bulk leakage monitoring device is expensive, at about 10 to 30% of the system price. Furthermore, this gas leak monitoring device requires periodic inspection and parts replacement every two years from the viewpoint of safety, and has the disadvantage that maintenance costs cannot be ignored.

Therefore, in order to solve the above problems, the applicants, etc.
It is equipped with a central operation panel and a plurality of terminals connected to the central operation panel via transmission lines and each connected to one or more gas equipment loads, and each gas equipment load is controlled by a control signal from the central operation panel. In a gas appliance monitoring and control system that transmits monitoring signals for each load from each terminal to a central operation panel, the central operation panel includes a means for measuring the total gas consumption flow rate of the system, and a means for measuring the total gas consumption flow rate of the system, A memory means in which a gas consumption flow rate for each load is written, and a means for reading out from the memory means the gas consumption flow rate of each gas equipment load that is indicated to be in operation by the monitoring signal and calculating the sum of these. and a means for comparing the measured total gas consumption flow rate with the calculated gas consumption flow rate and generating a gas leak detection signal when the difference between these gas consumption flow rates exceeds a predetermined value. We first proposed a gas equipment monitoring and control system (patent application filed in 1973).
No. 8-233623).

According to this gas equipment monitoring and control system, most of the equipment configuration originally used as a gas equipment monitoring and control system can be used without adding additional expensive equipment for gas leak detection such as a gas leak detection sensor or a gas leak receiving panel. Gas leak detection can be realized at low cost by reusing and adding or changing a few parts.

However, although the gas equipment monitoring and control system related to this prior application has a gas leakage judgment processing function, the error in the gas flow rate, which is the judgment standard as a result of supplementary testing, is particularly low, especially at low flow rates. It turned out that it was about 10%. This is more accurate than current gas leak detectors, but from a safety standpoint, higher accuracy is preferable.

(Object of the Invention) The present invention has been made in view of the above-mentioned problems with the conventional type, and has an object to improve the accuracy of the gas leakage judgment processing function without adding expensive equipment to the gas appliance monitoring and control system. With the goal.

The present inventor focused on the fact that the gas consumption flow rate varies depending on the gas temperature and gas pressure, which causes an error when determining gas leakage. When comparing the total gas consumption flow rate of each gas equipment load calculated from the gas consumption flow rate written in The inventors have found that the object can be achieved and have arrived at the present invention.

In other words, according to the Boyle-Charles law, the converted gas consumption flow rate v2 is: V2 = V+ P'+ (273+j2) P2
(273+i+) (vl: Gas consumption flow rate before conversion, tl: Gas temperature before conversion, tl: Gas cap after conversion!it, P+: Gas pressure before conversion, P2: Gas pressure after conversion) However,
Normally, a pressure regulating valve is installed on each load side, so
= P, so V2 = V, + (273+ tl ) / (27
3+tl)...(Formula A) It can be converted as follows.

Therefore, for example, when tl is 0°C and tl is 1°C, (2
72/273) From V2-0.996V2, the gas flow rate changes by 0.4%, and when tl is 0°C and 11 is 15°C, it changes by 6%, so the change in gas flow rate due to temperature is a gas leak. It can be seen that this results in a large error in the judgment processing function.

(Structure of the Invention) The present invention includes means for centrally controlling a plurality of gas appliance loads and measuring the total gas consumption flow rate of the system, and a memory means in which the gas consumption flow rate for each gas appliance load is written in advance. means for monitoring whether each load is in operation; means for reading the gas consumption flow rate of each gas equipment load during operation from the memory means and calculating the sum thereof; and calculating the total gas consumption by this measurement. In a gas equipment monitoring and control system, the gas equipment monitoring and control system comprises a means for comparing the flow rate with a calculated gas consumption flow rate and generating a gas leak detection signal when the difference between these gas consumption flow rates exceeds a predetermined value. The present invention is characterized in that it includes a sensor for detecting the temperature of the gas passing through the means, and means for converting the total gas consumption flow rate measured and the calculated gas consumption flow rate into a gas volume at the same reference temperature.

(Explanation of Examples) Hereinafter, the present invention will be explained in detail with reference to the drawings.

FIG. 1 shows a block configuration of a gas heating monitoring and control system according to an embodiment of the present invention. The system shown in the figure is installed in a school, for example, and includes a central control panel (gas heating central monitoring double-view control panel) 1 placed in the air for staff, etc., and a two-wire transmission line 2 connected to the central control panel 1. It is composed of a plurality of terminals 3 (3, -1, 3-2°, . . . , 3-n) etc. connected through the terminal. The central operation panel 1 has a motor valve (MV
) A control panel 4, a gas flow meter 5, a gas temperature sensor 6, a monitoring cock 7 for each room, etc. are connected. Also, each terminal 111
3-1, 3-2°..., 3-n are each provided with one or more control channels, and each channel has one or more gas heaters (
group) 8 (8-1, 8-2, . . . , 8-n) are connected, and temperature sensors 9 (9-1, 9-2, .
..., 9-n) are connected. Furthermore, after the gas piping from the gas main passes through the main valve, strainer and motor valve (not shown), on the one hand, each gas heater 8
-1.8-2. .

The central operation panel 113 and each terminal 3 are equipped with a central processing unit (CPU) such as a microprocessor, memory, etc.
Data is transmitted between them, thereby controlling each gas heater 8 on and off, and monitoring the operating status of each gas heater 8 on the central operation panel 1. That is, the central operation M1 randomly or cyclically addresses the other terminals 3 and sends out control signals, and each terminal 3
The operation of each gas heater 8 is controlled according to this control signal, and a monitoring signal indicating the operating status of each gas heater 8, that is, an operation (ignition) monitor signal, an operation stop (extinguishing)
A monitor signal, a misfire monitor signal, etc. are sent back, and if necessary, a monitoring signal from the temperature sensor 9 or a gas leak detection sensor (not shown) is also sent back if necessary.

Motor valve control! 114 controls the opening and closing of motor valves connected in the gas piping according to commands from the central operation panel 1, and returns a motor valve monitoring signal. The central operation panel 1 uses this monitoring signal to monitor and display the opening and closing of the motor valve.

The flowmeter 5 measures the total gas consumption in this system, and generates a flow rate pulse signal (for example, 1 pulse/1 or 1 pulse 15 J) for each unit gas consumption flow rate, and sends it to the central operation panel 1. .

In the central operation W1, the gas consumption flow rate (for example, 17 minutes) and the integrated flow rate (for example, i) are calculated by counting the flow rate pulse signals.

The gas consumption flow rate and cumulative flow rate are displayed on a numerical display (described later) or printed out using a printer (not shown).

The gas temperature sensor 6 detects the temperature of the gas passing through the flow meter 5, and is installed, for example, by screwing a sensor such as a thermistor into a gas pipe near the flow meter 5. Then, the temperature of the gas passing through the flow meter 5 is used as a sensor signal, which is A/D converted (for example, in the range of -10 DEG C. to 21 DEG C. in units of 1 DEG C.) and then transmitted to the central control panel 1.

Each room monitoring cock 7 detects the presence or absence of gas supply to each gas cock installed in each room other than the gas heater 8, monitors the opening and closing of the cock, and sends the monitoring signal to the central operation panel 1. , the opening and closing of each gas cock will be displayed on the monitor.

The gas heater 8 is equipped with an electric valve, an ignition device, etc., which are driven by electric power supplied via the terminal 3 and a signal given from the terminal 3. It also has ignition detection means based on flame or temperature, and sends an ignition monitor signal to the terminal 3 when ignition occurs. The terminal device 3 determines ignition or misfire based on the ignition monitor signal, operation signal, etc., and sends the determination result to the central operation panel 1 as a monitoring signal.

In addition, in this system, manual control to turn on and off each gas heater 8 based on input from a key switch etc. provided on the central operation panel 1, and a predetermined time schedule stored in the memory within the central operation panel 1 are performed. It is possible to perform automatic control of each gas heater 8 based on the following.

Next, the operation of the system shown in FIG. 1 will be explained with reference to the flowchart shown in FIG.

In the system shown in Figure 1, during normal operation, the central control panel 1
However, each gas heater 8 is operated according to a pre-stored program, that is, a time schedule.

FIG. 2 shows a procedure for checking gas leakage in the central operation panel 1 of the system shown in FIG. This operation is carried out in parallel with the above-mentioned normal operation.The memory of the central control panel 1 contains a read-only channel data table that stores individual unit flow rate data for each gas heater. An area for storing the gas consumption simulation value (S value) as the sum of the unit consumption flow rate of the gas heater and the actual gas consumption amount (Q value) obtained by counting the flow rate pulses from the flow meter 5, and A correction data table and the like are provided for converting the Q value into a predetermined reference temperature.

In the channel data table, each gas heater 8
A value obtained by converting the consumed flow rate into the consumed flow rate at a predetermined reference temperature is stored in the memory of the central operation panel 1. The consumption flow rate of this gas heater 8 at the reference temperature is determined by operating each gas heater for several minutes, calculating the gas consumption flow ω per unit time from the flow rate H at that time, and then using the above-mentioned formula A. , for example, converted to the consumption flow rate at 0°C.

Referring to FIG. 2, first, the S value and Q value in the memory are cleared for the first minute, and then the gas leak simulation (gas leak check) is started. In this gas leak simulation, the following operations are repeated every minute. That is, first, the operation monitor stored in a predetermined area in the memory is checked, and the consumption flow rate of each gas heater that is determined to be in operation through this check is sequentially read out from the channel data table and added, and this added value is calculated. is stored as an S value. Also, in parallel with this S value calculation, the gas consumption flow rate for one minute (Q value) is determined. Here, the sum of the gas consumption flow rate every 15 seconds, that is, the average value for 1 minute, is calculated based on the number of pulses for 15 seconds, and then, based on the gas temperature obtained from the gas moisture sensor 6, formula A is used to calculate the flow rate at the reference temperature. The gas consumption flow rate is used as the Q value.

Next, the S value and the Q value are compared, and it is determined whether the difference between the S value and the Q value is less than or equal to a reference value. Note that, taking into consideration the measurement error of the Q value and the calculation error of the S value, the above standard 1icf (ratio (%) to the S value) is adjusted according to the gas flow rate range.
Although the reference value is changed, the reference value may be set to a constant value. In the above judgment, if the difference between the S value and the Q value is smaller than the reference value, the gas leak detection counter is cleared, and if it is larger than the reference value, the detection counter is incremented, and then the S value in the next 1 minute is The above simulation operation is repeated for the Q value.

In this manner, in each minute-by-minute gas leak simulation, when the same determination is made four times in a row and the count value N of the detection counter reaches 4, it is determined that there is a gas leak. In this case, first, send a command to stop operation of all channels to the terminal 3.
Send to. After confirming that all channels have stopped, pulse measurement is performed after a predetermined period of time, for example, 15 seconds. This pulse measurement is carried out for, for example, 30 to 45 seconds, and if there are no more than 3 pulses within this time, it is determined that there is an error in gas leakage staining rather than a gas leak, and the operation is restarted. Repeat the leakage simulation. In the above-mentioned pulse measurement after stopping all channel operation, if there are 3 or more pulses within the above-mentioned time, it is determined that a gas leak has actually occurred, and a motor valve close command is sent to the motor valve control panel 4, and the gas After indicating the leakage and lighting up the ED, an alarm is issued and the operation of the CPLI is locked.

After stopping the alarm, the system remains in a state where heating operation is stopped, so the manager has to request the gas company to come out for maintenance.

(Effects of the Invention) As described above, the present invention provides a gas appliance monitoring and control device that centrally performs operation control and monitoring of each gas appliance from a central operation panel via a terminal, In gas equipment monitoring and control systems that detect gas leaks by comparing the total gas consumption flow rate measured by The accuracy of the gas leakage determination processing function can be improved by, for example, several percent without adding any equipment.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the overall configuration of a gas appliance number monitoring and control system according to an embodiment of the present invention, and FIG. 2 is a flowchart for explaining the operation of the system shown in FIG. 1: Central operation panel, 2: Transmission line, 3 (3-1, 3-2,..., 3-n): Terminal, 4: Motor valve control panel, 5: Maximum gas flow, 6: Gas Temperature sensor, 7; Monitoring cock for each room, 8 (8-1, 8-2,..., 8-n): Gas heater. 9; Temperature sensor.

Claims (1)

[Scope of Claims] 1. Means for centrally controlling a plurality of gas appliance loads and measuring the total gas consumption flow rate of the system; a memory means in which the gas consumption flow rate for each gas appliance load is written in advance; means for monitoring whether each load is in operation;
Means for reading the gas consumption flow rate of each gas equipment load during operation from the memory means and calculating the sum of these, and comparing the total gas consumption flow rate by this measurement and the gas consumption flow rate by calculation, A gas appliance monitoring and control system comprising: means for generating a gas leak detection signal when the difference exceeds a predetermined value; 1. A gas equipment monitoring and control system comprising: a gas consumption flow rate; and a means for converting the calculated gas consumption flow rate into a gas volume at the same reference temperature.