JPH0148493B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a fluid leakage detection device for detecting fluid leakage from a fluid transport line.

For example, in oil pipelines, the following laws (for example, the Oil Pipeline Business Act, the Fire Service Act) and the like require monitoring of oil leaks in the piping system due to the need for safety. There are two methods for detecting oil leaks, called the line bus method or the flow rate difference method, which detects based on the flow rate difference between the inlet and outlet sides of the pipeline. Broadly classified.

First, leakage detection using an analog transmission method will be explained. FIG. 1 is a configuration diagram of a conventional fluid leakage detection device. First, the volumetric flow rates Q _i and Q _p on the inlet side and outlet side of the piping system line L are simultaneously measured by the first and second flow rate transmitters F _i and F _p . The flow rate pulse signal from the second flow rate transmitter F _p on the outlet side is transmitted by a telemeter TE2 (pulse frequency telemeter).
The pulse train signal is FS-modulated and transmitted to the entrance side telemeter TE1 via the communication line F as a pulse train signal. Then, a flow balancer (product name), that is, a flow rate difference calculation device FB, is used to determine a predetermined time T between the inlet side and the outlet side of the piping system line L based on the flow rate pulse signals from the first and second flow rate oscillators F _i and F _p . The flow rate difference statistical value _T 〓 ^o (Q _i −Q _p ) is calculated for each time, and the flow rate difference calculator FB calculates the flow rate difference statistical value _T 〓 ^o (Q _i −Q _p ) and the preset alarm set value Q _s1 and A comparison is made with the shearing set value Q _s1 . FIG. 2 is a diagram showing the flow rates at which alarm and shrunken signals are generated. As shown in Fig. 2, if the flow rate difference statistical value _T 〓 ^o (Q _i −Q _p ) exceeds the alarm set value Q _s1 and the cut-off set value Q _s2 at every predetermined time T, an alarm indicator (not shown) will be displayed. An alarm or shear failure signal is issued.

Such a device has the advantages of a simple circuit configuration, low cost, and the ability to simultaneously read the volumetric flow rates Q _i and Q _p on the inlet and outlet sides. There are some drawbacks. That is, since the telemeters TE1 and TE2 use the audio frequency band, their transmission speed is limited to a maximum of 1200 baud. As a result, when the pulse width of the signal to be transmitted is 1/1200 [sec] or less, it becomes impossible to transmit a pulse number exceeding 600 [pulses/sec] even if the on/off ratio is equal.

Furthermore, as the transmission speed increases, the pulse width to be transmitted becomes narrower, making the transmitted signal more susceptible to external noise and the like. However, since an error detection function for removing erroneous signals due to external noise and the like is not provided, it is difficult to remove external noise and the like.

From the above, when adopting this method, the number of flow pulses should be determined by taking into consideration the on/off ratio, etc.
It is designed to be 100 [pulses/sec] or more.
Therefore, in this type of fluid leakage detection device,
The number of pulses of the flow rate pulse signal is 100 [pulses/sec]
It becomes difficult to apply if it exceeds.

Next, leakage detection using the digital transmission method will be explained. FIG. 3 is a configuration diagram of a conventional fluid leak detection device. First, similar to the device shown in FIG. 1, the flow rate pulse signals on the inlet side and outlet side of the piping system line are counted by the respective counters 11 and 21 of the inlet side measuring section 10 and the outlet side measuring section 20,
After that, the controller 12 of the stward program method,
22, the flow rate data _T 〓 ^o Q _i , _T 〓 ^o
It is stored in a part of the memory 13, 23 as Q _p . Then, the flow rate data _T 〓 ^o Q _p on the outlet side is read out from the memory 23 according to a command from the control unit 22, and transmitted from the communication control unit 24 to the communication control unit 14 of the inlet side measurement unit 10 via the communication line LN and stored in the memory. 13. After this, the difference in the flow rate data stored according to the command from the control unit 12, that is, _T 〓 ^o Q _i − _T 〓 ^o
The calculation Q _p is performed, and if the calculation result is larger than the preset value Q _s , the output section 15
An alarm signal is output from the alarm indicator 16, and the alarm indicator 16 lights up.

The counters 11 and 21 of such devices are usually
Since it uses 12 bits, it can only count up to 4095 in binary. Therefore, if the number of pulses of the flow rate pulse signal is about 1000 [pulses/sec], the counters 11 and 21 will overflow in about 4 seconds. Therefore, flow rate data to memories 13 and 23
Sampling of _T 〓 ^o Q _i and _T 〓 ^o Q _p is performed as follows. Figure 4 is a diagram showing the sampling time (predetermined time T), where QI is the inlet flow pulse signal, A is the sampling time of the inlet flow pulse signal, and B and C are sampling time delays of the outlet flow pulse signal. The case of H and the case of synchronization are shown, and QO shows the outlet side flow rate pulse signal. For example, if the sampling time T is 30 seconds, the outlet side flow rate QO
If is 1000 [pulses/sec], counter 11,
Flow rate data _T 〓 ^o Q _i , _T 〓 ^o Q _p are read out in 10 times every 3 seconds to prevent the flow rate data 21 from overflowing. That is, _3S 〓 ^o Q _p + _6S 〓 ^3S Q _p +...+ _30S 〓 ^27S Q _p , and the flow rate data of 30 [seconds] x 1000 [pulses/second] = 30000 pulses is stored in the memory 21, and is updated every 30 seconds. The data is transmitted to the memory 13 via the communication control units 24 and 14.

However, the read sampling time T when employing the stward programming method is
Since it depends on 2 and 22 programs, it is not constant and varies depending on the number of programs being processed at a certain time. For example, when the number of pulses transmitted by each flow rate transmitter on the inlet and outlet sides is 1000 [pulses/sec], if the sampling time T on the inlet side is 15 [msec] longer and the sampling time T on the outlet side is 15 [msec] shorter, the The time difference is 30 [msec], resulting in a difference of 30 pulses in the number of pulses. If one pulse corresponds to 1, it will be detected that 30 leaks have occurred in a time difference of 30 seconds, which is inconvenient as it may cause erroneous measurements or false alarms. For this reason, conventionally the counter 1
This problem was dealt with by giving priority to the operation mode of the read processing programs No. 1 and 21 over other programs, but this had the disadvantage that the process monitoring cycle by the normal monitoring program in the process computer system became longer. It was hot.

The present invention was made based on the above circumstances, and
A fluid that can eliminate variations in the reading time interval between the reading points of each counter on the inlet and outlet sides of a piping system line, and can also eliminate variations in the sampling time for collecting flow rate data, thereby preventing false measurements and false alarms. An object of the present invention is to provide a leakage detection device.

An embodiment of the present invention will be described below with reference to FIGS. 5 to 7. Note that the same parts as in FIG. 3 are given the same reference numerals and detailed explanations will be omitted. Fifth
The figure is a configuration diagram of a fluid leakage detection device according to the present invention. As shown in FIG. 5, this fluid leakage detection device is constructed by replacing the counters 11 and 21 shown in FIG. 3 with inlet side and outlet side counting sections C1 and C2, respectively. This inlet side and outlet side counting section C
1, C2 is a clock device as a counting time setting means
It consists of a CL, a gate circuit G, and a counter CT as a counting means. The clock device CL outputs a gate pulse for a predetermined time (for example, 3 seconds) to set the counting time of the counter CT. The gate circuit G includes gates G11 and G21 that send a flow rate pulse signal during a period when the gate pulse from the clock device CL is at an "H" level, and a gate G12 that sends a flow rate pulse signal during a period when the gate pulse is at an "L" level. G22, and not gates G13 and G23 for inverting the gate pulse. The counter CT includes a 12-bit first counter CT11, CT21 that counts flow rate pulse signals from gates G11, G21, and gates G12, G21.
12-bit second counters CT12 and CT22 that count the flow rate pulse signals from 22, and a clock device.
1-bit counters CT13 and CT23 that count gate pulses from CL and not gate G1
3 and 1-bit counters CT14 and CT24 that count gate pulses from G23. Furthermore, this fluid leakage detection device includes a calculation unit (1) that calculates the difference in flow rate between the inlet side and the outlet side of the piping system line based on the flow rate data read from the counter CT and stored in a part of the memories 13 and 23. (not shown) is provided. Also, the control section 1
1 and 21, the first and second counters CT1
1, CT21, CT12, memory 13 from CT22,
A clock device for time data is built in, which adds time data representing the time corresponding to the flow rate data sent to 23.

Next, the operation of the apparatus configured as described above will be explained. Note that since the counting sections C1 and C2 have the same configuration, the operation thereof will be explained with respect to the outlet side counting section C2, and the explanation of the inlet side counting section C1 will be omitted. FIG. 6 is a waveform diagram of each part in the exit side counting section C2. Fluid is fed into the piping system line (not shown) and the first
Each flow rate is detected by a second flow rate transmitter. Then, a flow rate pulse signal Q0 as shown in FIG. 6 is input from the outlet side flow rate transmitter to the outlet side counting section C2. Here, the clock device of this counting section C2
CL outputs a gate pulse g of a predetermined period (3 seconds) shown in FIG. 6, and sends it to each gate G21 to G23 and counters CT21 to CT24. This allows the first
The counter CT21 counts the flow rate pulse signal Q01 during the "H" level period of the gate pulse g1 to the gate G21, that is, the period t1, t3, t5, . . . of the gate pulse g. Meanwhile, the second counter CT
22 counts the flow rate pulse signal Q02 during the "H" level period of the signal g2 obtained by inverting the gate pulse g at the gate G22, that is, during the periods t0, t2, t4, . . . of the gate pulse g. That is, the flow rate pulse signal Q0 is counted alternately at predetermined time intervals by the first and second counters CT21 and CT22. Further, the counter CT23 receives the signal g3 shown in FIG.
Counter CT24 counts each signal g4.
The counted flow rate data is sent to each counter CT21, along with time data from a time data clock device built into the control unit 22, according to a command from the control unit 22.
It is stored in a part of the memory 23 during the off period of the gates G21 and G22 for the CT22. FIG. 7 is a diagram showing the contents of data stored in the memory 23. As shown in FIG. 7, time data TD _p -TD _o are attached to the flow rate data CD _p -CD _o and stored in the memory 23 .

When the flow rate data CD _p to _{CD o} stored in the memory 23 in this way reaches a predetermined amount, the control unit 2
2, the flow rate data CD _p to _{CD o} are stored in memory 2.
3 and the communication line from the communication control unit 24.
It is sent to the communication control unit 14 on the entrance side via the LN,
Furthermore, it is stored in a part of the memory 13 on the entrance side. Then, according to a command from the control unit on the inlet side, the flow rate data between the inlet side and the outlet side is determined based on the transmitted flow rate data CD _p to _{CD o} on the outlet side and the flow rate data on the inlet side obtained in the same way as for the outlet side. The flow rate difference is determined in the calculation section. In other words, the flow rate difference { _t1 〓 ^o Q _i + _t2 〓 ^t1 Q _i +…+ _to 〓 ^tn-1 Q _i }−{ _t1 〓 ^o Q _p + _t2 〓 ^t1 Q _p +…+ _to 〓 ^tn-1 Q _p } The following calculation is performed.

As a result, if the calculated flow rate difference is larger than the preset set value _Qs , an alarm signal is output from the output section 15 and an alarm display is performed on the alarm indicator 16.

According to the device configured in this way, the counting time of each of the first and second counters of each of the counting units C1 and C2 provided outside of the control units 12 and 23 of the Stewart program type is controlled by each clock device CL. Since the flow rate data is obtained by making the counting constant and performing the counting alternately, the counting time of the first and second counters becomes constant and there is no variation. The calculated flow rate data can always be obtained as data over a fixed period of time and corresponds accurately to the flow rate. Therefore, accurate flow rate data can be read even if the reading timing changes due to the influence of another program processing, and it is also possible to accurately read and calculate high-speed flow rate pulse signals, making data collection easier. False alarms due to cycle fluctuations are no longer reported.

Furthermore, since time data is attached to the flow rate data and stored in the memories 13, 23, it is possible to set a desired delay time to each flow rate data on the inlet side and the outlet side of the piping system line in the calculation. .

Note that the present invention is not limited to the above embodiment. For example, in the above embodiment, time data is obtained from the time data clock device built into the control units 12 and 22, but this is obtained from the time data clock device built in the control units 12 and 22;
It may be obtained from each clock device CL of 2. Also, either the rising edge or the falling edge of the gate pulse g may be used for the time of the time data. Furthermore, a number may be attached to each flow rate data instead of the time data.

In the embodiment described above, the flow rate difference between the inlet side and the outlet side is determined by the arithmetic unit on the inlet side, but this may be done on the outlet side or both the inlet side and the outlet side.

Furthermore, counters CT11, 21, CT12, 22
Although the flow rate data is continuously obtained by using the above, it is also possible to use a set of counters to obtain the flow rate data intermittently.

Further, this device may be suitable for detecting leaks not only in oil pipelines but also in pipelines for various chemical products (liquids), water supply and sewage pipelines, and the like.

According to the present invention, the first and second counters are provided, and the counting time is made constant by the counting time setting means, and the counting is performed alternately to obtain flow rate data, and the difference in flow rate between the inlet side and the outlet side is calculated. Since it is determined by calculation, even if there is variation in the reading time interval of each counter on the inlet side and outlet side of the fluid transport line, accurate flow rate measurement can be performed on both the inlet side and the outlet side. Therefore, it is possible to provide a fluid leakage detection device that can prevent erroneous measurements and false alarms and improve leakage detection ability.

[Brief explanation of drawings]

Fig. 1 is a block diagram of a conventional fluid leakage detection device using an analog transmission method, Fig. 2 is a diagram for explaining the operational functions of the device shown in Fig. 1, and Fig. 3 is a diagram showing a fluid leakage detection device using a conventional digital transmission method. FIG. 4 is a diagram for explaining the operation of the device shown in FIG. 3, FIG. 5 is a configuration diagram showing an embodiment of the fluid leak detection device according to the present invention, and FIG. 6 is a diagram of the configuration of the detection device. FIG. 7 is a waveform diagram of each part of the counting section in this device, and is a schematic diagram of flow rate data stored in the memory. 12, 22...control unit, 13,23...memory, 1
4, 24...Communication control section, 15...Output section, 16...Alarm indicator, C1...Entrance side counting section, C2...Exit side counting section, CL...Clock device, G...Gate circuit, G11,
G12, G21, G22...Gate, G13, G2
3...Not gate, CT...Counter, CT11,
CT21...first counter, CT12, CT22...
Second counter.

Claims (1)

[Scope of Claims] 1. A first flow rate transmitter that emits a flow rate pulse proportional to the flow rate on the inlet side of the fluid transport line;
a second flow transmitter that emits a flow pulse proportional to the flow rate at the outlet side of the fluid transport line;
Each counting time setting means provided on the inlet side and the outlet side of the fluid transport line, respectively, and each counting time set by the counting time setting means provided on the inlet side and the outlet side of the fluid transport line, respectively. and first and second counters that alternately count each flow rate pulse signal from the first and second flow rate transmitters, respectively, and counting start times of these first and second counters. a time detection means for detecting and adding time data to the flow rate data from these first and second counters; and a time detection means provided at the inlet and outlet sides of the fluid transport line, respectively, and the flow rate data to which the time data is attached. a transfer means for transferring the flow rate data and time data stored in these storage means to the storage means provided on either the inlet side or the outlet side of the fluid transport line; a calculation means for calculating the difference between the cumulative flow values on the inlet side and the exit side of the fluid transport line from each flow rate data stored in the storage means on the side transferred by the transfer means; and the cumulative value calculated by the calculation means. A fluid leakage detection device comprising: an alarm indicator that determines that a leak has occurred in the fluid transport line and issues an alarm if the flow rate value is larger than a preset set flow rate value difference. 2. The fluid leak detection device according to claim 1, wherein the calculation means is provided on either the inlet side or the outlet side of the fluid transport line.