Monitoring system

Abstract

This system provides a simple configuration for monitoring outdoor tank storage facilities. [Solution] The monitoring system 1 includes a plurality of intrinsically safe explosion-proof detection systems 100. The intrinsically safe explosion-proof detection system 100 includes a detector 10 that monitors environmental information or determines whether a predetermined abnormality has been detected based on information detected by a sensor, a master unit 68 that transmits the determination result of the detector 10 to a higher-level device 80, a power supply unit that supplies power to the master unit 68 and the detector 10, a transmission cable unit 90 that includes a signal transmission line connecting the detector 10 and the master unit 68 and supplies power to the detector 10 from the power supply unit, and a power control unit that controls the supply of power from the power supply unit to the detector 10 according to a predetermined monitoring cycle or detection cycle for environmental information or a predetermined type of abnormality. The plurality of intrinsically safe explosion-proof detection systems 100 are used to monitor environmental information or detect the predetermined abnormality in an outdoor tank storage facility.

Description

Technical Field

[0001] The present invention relates to a monitoring system.

Background Art

[0002] For floating roof tanks, which are outdoor storage tanks, workers climb onto each unit every day to conduct visual inspections. In this visual inspection, abnormalities such as the inclination of the floating roof, leakage of dangerous substances, and rainwater retention are inspected.

[0003] Not only regular inspections but also prompt confirmation is obligatory during disasters such as earthquakes, heavy rain, and storms.

[0004] In addition, a wireless intrinsically safe explosion-proof detector that is inexpensive and compatible with various sensors has been proposed (Patent Documents 1 to 3).

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Patent Document 5

Patent Document 6

Patent Document 7

Patent Document 8

Patent Document 9

Patent Document 10

[0006] On the other hand, in the case of outdoor storage tanks with internal floating lids, internal inspection itself is not easy due to the fixed roof.

[0007] Based on the above, currently, inspecting storage tanks at outdoor tank storage facilities is a significant burden, and there is a risk that in the future, due to the retirement of inspectors, sufficient inspections may not be possible.

[0008] While many fixed-installation monitoring devices such as cameras exist, there are few devices with Ex ia intrinsically safe explosion-proof construction that can handle the ZONE 0 explosion-proof areas set up in various locations on outdoor storage tanks, and the high cost of the system (several million yen per unit) is a challenge.

[0009] Furthermore, due to the high cost of the system unit, conventional technology assumes a system where one monitoring device can provide an overview of an entire tank.

[0010] Therefore, a pan-tilt mechanism using an electric pan-tilt head became essential, and due to explosion-proof restrictions, installation locations were limited to explosion-proof areas below ZONE 1, and this also became a further cost factor for the system.

[0011] Furthermore, with the above configuration, it was difficult to monitor the entire floating roof in response to fluctuations in its height due to the amount of oil stored, and there was a risk that fires occurring in the weather seal area could be hidden from view.

[0012] As a result of the above, its practical use was limited, and its main application was to temporarily install monitoring equipment, which was owned by a small number of businesses, after detecting an anomaly to enable centralized monitoring.

[0013] Furthermore, in recent years, low-power CMOS cameras have become readily available at low cost, and when combined with the intrinsically safe explosion-proof detectors mentioned above, the feasibility of creating inexpensive wireless surveillance equipment compatible with ZONE 0 explosion-proof areas has increased.

[0014] On the other hand, when installing the detector in an outdoor tank storage facility, the vast size of the site necessitated long-distance wireless transmission (several hundred meters to several kilometers), while the constraints of the intrinsically safe explosion-proof structure prevented the use of high-power (long-range) wireless communication.

[0015] This invention was made to solve the above problems and aims to provide a monitoring system that can monitor outdoor tank storage facilities with a simple configuration. [Means for solving the problem]

[0016] The monitoring system according to the first embodiment includes a plurality of intrinsically safe explosion-proof detection systems, each comprising: at least one detector that monitors environmental information or determines whether a predetermined abnormality has been detected based on sensor information detected by a sensor and outputs it as a digital signal; a master unit that aggregates the digital signals acquired by each of the detectors and transmits them to a higher-level device; a power supply unit that supplies power to the master unit and each of the detectors; a transmission cable unit that connects the detectors and the master unit and includes a signal transmission line for transmitting the digital signals, and also supplies power to the detectors from the power supply unit; and a power control unit that controls the supply of power from the power supply unit to each of the detectors according to a predetermined monitoring cycle or detection cycle for the environmental information or the predetermined type of abnormality in the detector. The system uses the plurality of intrinsically safe explosion-proof detection systems to monitor environmental information or detect the predetermined abnormality in an outdoor tank storage facility. The system includes a plurality of intrinsically safe explosion-proof detection systems, each comprising: at least one detector that monitors environmental information or determines whether a predetermined abnormality has been detected based on sensor information detected by a sensor and outputs it as a digital signal; a master unit that aggregates the digital signals acquired by each of the detectors and transmits them to a higher-level device; a power supply unit that supplies power to the master unit and each of the detectors; a transmission cable unit that connects each of the detectors and the master unit to the power supply unit and includes a signal transmission line for transmitting the digital signal, and also supplies power to the detectors from the power supply unit; and a power control unit that controls the supply of power from the power supply unit to each of the detectors according to a predetermined monitoring cycle or detection cycle for the environmental information or predetermined type of abnormality in the detector. The system uses the plurality of intrinsically safe explosion-proof detection systems to monitor environmental information or detect predetermined abnormalities in an outdoor tank storage facility.

[0017] The monitoring system according to the second embodiment includes a plurality of intrinsically safe explosion-proof detection systems, which include: an acquisition unit that acquires sensor information detected by a sensor; a detector that monitors environmental information or determines whether or not a predetermined abnormality has been detected; a transmitting and receiving unit that converts the monitoring result or determination result from the detector into a digital signal and transmits the digital signal to a higher-level device via wireless communication; a period storage unit that stores predetermined monitoring or detection periods for each type of environmental information or predetermined abnormality; a power supply unit that supplies power; and a power control unit that controls the supply of power from the power supply unit according to the monitoring period or detection period corresponding to the environmental information or predetermined abnormality. The plurality of intrinsically safe explosion-proof detection systems are used to monitor the environmental information or detect the predetermined abnormality in an outdoor tank storage facility.

[0018] The monitoring system according to the third aspect monitors environmental information or determines whether a predetermined abnormality has been detected based on sensor information detected by a sensor, and outputs at least one detector as a digital signal; a master unit that aggregates the digital signals acquired by each of the detectors and transmits a signal to a higher-level device; a power supply unit that supplies power to each of the master unit and the detectors; a signal transmission line provided to connect between the detectors and the master unit for transmitting the digital signal, and a transmission cable unit that supplies power from the power supply unit to the detectors; and a power supply control unit that controls the supply of power from the power supply unit for each of the detectors according to a predetermined monitoring period or detection period for the environmental information or the type of the predetermined abnormality in the detectors. A plurality of intrinsically safe explosion-proof detection systems, a gateway that converts information transmitted from each of the master units of the plurality of intrinsically safe explosion-proof detection systems into a protocol used on the higher-level device side, and a repeater that relays transmission between each of the master units of the plurality of intrinsically safe explosion-proof detection systems and the gateway. When the connection with any of the master units with which communication has been established is interrupted, the repeater transmits information of the master unit whose connection has been interrupted as a response signal to the master unit that received the signal transmission from a communication-established master unit different from the master unit whose connection has been interrupted, at the timing when the signal transmission from the communication-established master unit is received, and causes the master unit to shift to a reception standby state in accordance with the timing when the master unit whose connection has been interrupted performs signal transmission, and issues a command to transmit the transmission data received from the master unit whose connection has been interrupted to the repeater.

Effect of the Invention

[0019] According to the monitoring system which is one aspect of the present invention, it is possible to monitor an outdoor tank storage with a simple configuration.

Brief Description of the Drawings

[0020] [Figure 1] It is a block diagram showing the configuration of the monitoring system according to the embodiment of the present invention. [Figure 2] It is a schematic diagram showing the configuration of the cable unit according to the embodiment of the present invention. [Figure 3] This is a block diagram showing the configuration of a repeater according to an embodiment of the present invention. [Figure 4] This is a block diagram showing the configuration of a gateway according to an embodiment of the present invention. [Figure 5] This diagram shows an example of the monitoring range of a detector. [Figure 6] This is a diagram illustrating the camera field of view of the detector's camera. [Figure 7] This diagram shows an example of the monitoring range of a detector. [Figure 8] This is a time chart showing the operation of a monitoring system according to an embodiment of the present invention. [Figure 9] This is a time chart showing the operation of a monitoring system according to an embodiment of the present invention. [Figure 10] This is a time chart showing the operation of a monitoring system according to an embodiment of the present invention. [Figure 11] This is a time chart showing the operation of a monitoring system according to an embodiment of the present invention. [Figure 12] This diagram illustrates how to transmit data received from a master unit whose connection has been interrupted to a repeater. [Figure 13] This is a time chart showing the operation of a monitoring system according to an embodiment of the present invention. [Figure 14] This is a cross-sectional view showing the configuration of the monitoring system related to the modification. [Figure 15] This is a schematic diagram showing the configuration of the monitoring system in a modified example. [Figure 16] This is a block diagram showing the configuration of the monitoring system in a modified example. [Figure 17] This is a block diagram showing the configuration of an intrinsically safe explosion-proof detector in a modified form. [Modes for carrying out the invention]

[0021] Embodiments of the present invention will be described in detail below with reference to the drawings.

[0022] <Summary of Embodiments of the Invention> In the monitoring system according to an embodiment of the present invention, an intrinsically safe explosion-proof detection system is used to acquire and monitor various environmental conditions of an outdoor tank storage facility.

[0023] The monitoring system incorporates innovative installation and monitoring methods for intrinsically safe explosion-proof detection systems, encompassing inspection and monitoring of various locations within the outdoor tank storage facility, particularly the floating roof tank. This enables advanced inspection and monitoring of various locations within the outdoor tank storage facility, as well as cost reduction.

[0024] Furthermore, in wireless transmission from the intrinsically safe explosion-proof detection system in the monitoring system to the higher-level device, wireless transmission using a repeater is controlled, enabling low-power operation of both the master unit and the repeater. This makes it possible to perform wireless transmission on the order of several hundred meters to several kilometers, which is necessary for outdoor storage tanks, with low power consumption, while satisfying the constraints of the intrinsically safe explosion-proof structure for both the master unit and the repeater.

[0025] <System Configuration> The following describes a monitoring system according to an embodiment of the present invention.

[0026] As shown in Figure 1, the monitoring system 1 according to an embodiment of the present invention comprises a plurality of intrinsically safe explosion-proof detection systems 100, a repeater 50, a gateway 60, a host device 80, and a base station 110. The intrinsically safe explosion-proof detection system 100 comprises a plurality of detectors 10 and a wireless base station 68. The wireless base station 68 comprises a barrier 70, a controller 72, a power supply unit 74, and a transceiver 76.

[0027] The power supply unit 74 and the multiple detectors 10 are connected by a cable 90. It is preferable to use energy harvesting for the power supply unit 74.

[0028] The higher-level device 80 comprises one or more of the following: a host computer 82, a DCS / PLC 84, and a control panel 86, and a wireless transceiver 88. The higher-level device 80 and the controller 72 are connected via wireless communication using the frequency band of LTE (Long Term Evolution) wireless technology. The intrinsically safe explosion-proof detection system 100, the repeater 50, and the gateway 60 are installed in hazardous locations, while the higher-level device 80 is installed in non-hazardous locations.

[0029] The controller 72 relays and converts digital signals between the detector 10 and the transceiver 76. The power supply unit 74 supplies power to each detector 10 via the cable unit 90. The power supply unit 74 is composed of a primary battery or a secondary battery.

[0030] The transceiver 76 includes an LTE wireless module 761 that performs signal exchange between the host device 80 and the controller 72 using wireless communication with an LTE wireless frequency band, and a short-range wireless module 762 that performs signal exchange between the repeater 50 and the controller 72 using wireless communication with a short-range wireless frequency band.

[0031] Multiple detectors 10 installed at hazardous locations are connected to the cable section 90 via T-branch connectors 90C, and receive power from the power supply unit 74 via the barrier 70 and the cable section 90. Here, the barrier 70 plays the role of limiting the energy supplied to the detectors 10 and suppressing overvoltage and overcurrent that occur in the event of a break or short circuit to a level that does not generate sparks that could lead to ignition. The controller 72 plays the role of converting the transmission signals between the detectors 10 and the higher-level device 80, and also monitors the status of the cable section 90 (such as monitoring for breaks and short circuits in the cable section 90).

[0032] Although Figure 1 shows a bus connection centered around a single cable section 90, a tree structure is also possible. Furthermore, the detector 10 may be connected to the cable section 90 with a 2P connector.

[0033] <Signal transmission (detector → wireless base station)> The cable section 90 is provided to connect the detector 10 and the wireless base station 68. As shown in Figure 2, the cable section 90 includes a signal transmission line 90B for transmitting digital signals and supplying power from the power supply unit 74 to the detector 10.

[0034] The detector 10 transmits signals (unique address, fire signal, abnormal temperature signal, status information, etc.) to the controller 72 via the signal transmission line 90B.

[0035] Data transmission will be carried out at a low transmission speed of at most about 30kbps. For example, the transmission speed of digital signals will be 10kbps to 30kbps. At the above speed, impedance matching does not need to be considered (signal reflection due to branching of the transmission line does not need to be considered), except for long-distance transmission (several tens of kilometers or more), and the detectors 10 can be arranged in a tree structure.

[0036] The signals transmitted separately from each detector 10 are converted into arbitrary transmission signals by the controller 72 and transmitted to the repeater 50 by the short-range wireless module 762, or to the host device 80 by the LTE wireless module 761.

[0037] <Signal transmission (wireless base station → detector)> In the intrinsically safe explosion-proof detection system 100 according to this embodiment, signals (address / status confirmation signals, etc.) transmitted from the controller 72 to the detector 10 are also transmitted using the signal transmission line 90B. However, there are limitations on the maximum current that can be supplied in hazardous locations, and if current for MBP transmission is supplied to all detectors 10, the number of detectors 10 connected to the cable section 90 is greatly limited. For example, the allowable output current of the FISCO power supply for a detector 10 (device group IIC, protection level ia) installed in a hazardous location (ZONE0) is 183mA (@output voltage 14[V]), and the maximum number of connectable detectors is 9. Therefore, the first transmission method transmits signals by modulating the voltage applied to the detector 10. For example, if the voltage applied to the detector 10 when not transmitting is 3[V], the voltage is dropped to 2.5V during transmission, and the Manchester-coded voltage is transmitted using voltage modulation (communication voltage ±0.5[V]). In this case, the applied current is the sum of the basic current consumption required for the anomaly detection operation multiplied by the number of installed units (for example, 1 [mA / unit] × 32 units = 32 [mA]). This method makes it possible to reduce the current consumption during communication on the same line as the MBP transmission line, and increases the number of detectors 10 that can be installed. With this method, it is possible to transmit signals to all detectors 10 simultaneously. However, the above method is just one example, and transmission methods such as signal formation using high-frequency voltage modulation of 0.75 to 1.0 [V] are also possible.

[0038] <Detector Configuration> The detector 10 according to an embodiment of the present invention monitors environmental information or determines whether a predetermined abnormality has been detected based on sensor information detected by the sensor, and outputs it as a digital signal.

[0039] The sensor is an externally connected sensor to the detector 10, and is one or more of the following: an infrared sensor, a temperature sensor, a vibration sensor, a thermocouple, a tilt sensor, a flame sensor, a visible image camera, a night vision thermocouple, a digital pressure sensor, a Bourdon tube pressure indicator reading sensor, a leak sensor, and a ToF sensor.

[0040] The detector 10 outputs the result of monitoring environmental information or determining whether a predetermined abnormality has been detected as a digital signal to the controller 72 using the cable section 90, and also exchanges digital signals with the controller 72.

[0041] The wireless base station 68, like the detector 10, may be externally connected to a sensor and, based on the sensor information detected by the sensor, monitor environmental information or determine whether a predetermined abnormality has been detected, and output it as a digital signal.

[0042] <Repeater Configuration> As shown in Figure 3, the repeater 50 includes a short-range wireless module 52 that performs signal exchange between the repeater 50 and the controller 72, and between the repeater 50 and the gateway 60, using wireless communication with a short-range wireless frequency band, a controller 54, and a power supply unit 56.

[0043] The controller 54 outputs the digital signal received from the controller 72 to the gateway 60 using the short-range wireless module 52, and also exchanges digital signals with the controller 72.

[0044] <Gateway Configuration> The gateway 60 converts the information transmitted from each of the wireless master units 68 of the multiple intrinsically safe explosion-proof detection systems 100 into a protocol used by the higher-level device 80.

[0045] As shown in Figure 4, the gateway 60 includes a short-range wireless module 62 that transmits and receives signals between the repeater 50 and the gateway 60 using wireless communication with a short-range wireless frequency band, an LTE wireless module 64 that transmits and receives signals between the gateway 60 and the host device 80 using wireless communication with an LTE wireless frequency band, and a controller 66.

[0046] The controller 66 outputs the digital signal received from the repeater 50 to the host device 80 using the LTE wireless module 64, and also exchanges digital signals with the repeater 50.

[0047] Each intrinsically safe explosion-proof detection system 100 is periodically activated at arbitrary time intervals (for example, every 3 hours to 1 day, pre-set) by an internal clock or timer installed in the wireless master unit 68 or each detector 10, and is powered off at all other times.

[0048] During startup, data is acquired according to the sensors connected to the wireless base station 68 or detector 10. This data is then aggregated in the wireless base station 68 and wirelessly transmitted to the host device 80 before transitioning to a power-off state.

[0049] In the above power-off state, only the internal clock or timer is operated to minimize power consumption.

[0050] This allows for battery operation for approximately 15 to 20 years. However, battery life will vary depending on the type of sensor connected.

[0051] When the above monitoring system 1 is installed on a floating roof tank 200, which is an example of an outdoor tank storage facility, the system monitors the tilt of the floating roof 200A and detects abnormal conditions of the floating roof 200A, such as leakage of hazardous materials, fire, rainwater accumulation, or temperature abnormalities (see Figure 5).

[0052] The sensors used are primarily visible-image cameras, but optical sensors such as infrared sensors (night vision sensors, array sensors) and flame sensors are also effective. Depending on the diameter of the floating roof tank 200, one or more sensors are installed per unit to monitor the entire floating roof 200A. Figure 5 shows an example where the monitoring range of four intrinsically safe explosion-proof detection systems 100 covers the entire floating roof 200A.

[0053] Furthermore, since the height of the floating roof of the floating roof tank 200 fluctuates depending on the amount of oil stored, it is preferable that, as shown in Figure 6(B), each detector 10 installed at the top of the tank wall 200B monitors the opposite bank of the floating roof tank 200 from its respective installation location.

[0054] The above is because, when monitoring the area below the installation location of the detector 10, the camera field of view required to include the floating roof 200A becomes larger, and there is a disadvantage in that a blind spot is created on the lower wall surface (Figure 6(B)).

[0055] Furthermore, by installing it at the top of the tank wall 200B, it is advantageous in that there are fewer obstacles that could obstruct wireless transmission, and wireless transmission is not affected by fluctuations in the height of the floating roof.

[0056] Here, for monitoring the tilt of the floating roof tank 200, the image obtained from the visible image camera, which is the sensor, may be output directly to the higher-level device 80 via the wireless base station 68, repeater 50, and gateway 60. Alternatively, the angle value may be output based on image analysis (such as singularity displacement analysis and recurrence edge analysis) performed on the detector 10 side. This makes it possible to reduce data communication charges. Triangulation using a ToF array sensor is also possible.

[0057] Similarly, leaks of hazardous materials or rainwater accumulation on the floating roof tank 200 may also be output as abnormalities by image analysis (difference detection, etc.) on the detector 10 side.

[0058] Furthermore, for fire monitoring inside the floating roof tank 200, infrared sensors or flame sensors may be installed one or more times per tank, similar to visible image cameras.

[0059] Alternatively, the monitoring direction of the detector 10 may be set with respect to the circumferential direction of the floating roof tank 200, and monitoring may be focused on the foam dam from the weather seal, where ring fires are likely to occur (Figure 7). In this case, the sensor used in the detector 10 is either a flame sensor or a temperature sensor.

[0060] Here, for transmission from the intrinsically safe explosion-proof detection system 100 to the higher-level device 80, as an example, the wireless base station 68 is equipped with either a Bluetooth Low Energy (BLE) or cellular LPWA (LTE-M, etc.) wireless module, and data is transmitted to the higher-level device 80.

[0061] In addition to the above, you may also use LPWA technologies such as LoRaWAN, low-power wireless communication, Wi-SUN, Wi-Fi HaLow, and Sigfox.

[0062] When using BLE, data is transmitted from the wireless access point 68 to the upper-level device 80 via the gateway 60. However, since the communication range is limited to approximately 100m (in BLE ver. 5), multiple repeaters 50 are installed between the gateway 60 and the repeater 50 as needed.

[0063] Similar to the detector 10, the repeater 50 operates with a battery life of approximately 15 to 20 years by being powered off when not communicating.

[0064] The controller 72 has a clock generator, a real-time clock, or a counter, and when the detector 10 and the repeater 50 are in standby mode (power off state), only the clock generator, real-time clock, or counter of the controller 72 operates.

[0065] <Operation of the monitoring system> Next, the operation of the monitoring system 1 according to an embodiment of the present invention will be described.

[0066] The detector 10 repeatedly performs a process at regular intervals to monitor environmental information or determine whether a predetermined abnormality has been detected based on sensor information, and to output it as a digital signal.

[0067] At this time, the following data is exchanged in monitoring system 1.

[0068] As shown in Figure 8, the repeater 50 manages multiple intrinsically safe explosion-proof detection systems 100, aggregates the transmission data collected from the wireless master units 68 of each intrinsically safe explosion-proof detection system 100, and transmits it to a higher-level device 80 (such as a PLC or DCS) or another repeater 50. Specifically, during transmission between the wireless master unit 68 and the repeater 50, both are driven with low power consumption by the following control.

[0069] First, the wireless base station 68 will be in initial mode for a certain period (for example, 2 days) after installation, and will activate at predetermined transmission time intervals (for example, every 10 minutes) to repeatedly transmit an advertisement signal to the repeater 50 or the host device 80.

[0070] On the other hand, the repeater 50 repeatedly enters a receive standby state only for twice the transmission time interval specified by the wireless base station 68 (20 minutes) within the startup time interval set by the wireless base station 68 (for example, 3 hours to 1 day / time), and remains powered off for the rest of the time.

[0071] Figure 8 shows an example in which each wireless base station 68 repeatedly transmits an advertisement signal while the repeater 50 is in a receiving standby state, until communication is established.

[0072] After the connection with the repeater 50 or the higher-level device 80 is established as described above, the system switches to normal mode. Figure 8 shows an example in which each wireless base station 68 is periodically started up at the normal startup interval (e.g., 3 hours) after establishing communication with the repeater 50.

[0073] As shown in Figure 9, each wireless base station 68 is periodically activated at a normal activation interval (for example, every 3 hours to 1 day, pre-set) to wirelessly transmit sensor information, and otherwise remains powered off. Figure 9 shows an example where each wireless base station 68 is periodically activated at a normal activation interval (for example, every 3 hours) and wirelessly transmits sensor information when the repeater 50 is in a receiving standby state.

[0074] The repeater 50 also returns an ACK to each wireless transmission from the wireless base station 68 (see Figure 8) and, if necessary, sends a command to the wireless base station 68 (such as changing the base station data transmission interval, stopping the connection, or requesting retransmission).

[0075] Furthermore, the transmission data aggregated by the repeater 50 is transmitted from the repeater 50 to the higher-level device 80 or another repeater 50 before the power is lost (see Figures 8 and 9).

[0076] Furthermore, the repeater 50 may further reduce the power consumption of the repeater 50 by specifying the next data transmission time (e.g., X minutes later) to each wireless base station 68 when it receives transmission data from each wireless base station 68 it controls, and by aggregating the data transmissions from each wireless base station 68 so that they occur in close proximity (low power consumption mode) (Figure 10).

[0077] In this case, the repeater 50 can reduce the reception waiting time to a time equal to the minimum transmission interval of the advertised signal from the wireless master unit 68 (e.g., 10 minutes / time) plus a margin time that takes into account errors in the internal clock or timer built into each repeater 50 (e.g., 12 minutes / time).

[0078] However, there are cases where sensors (such as flame sensors) are connected that do not perform scheduled data transmission at regular intervals on the wireless base station 68 side, but instead transmit abnormal conditions as alarms instantaneously.

[0079] In this case, since it is conceivable that the repeater 50 may be unable to establish a connection due to a power outage, or that data transmission may not be instantaneous, the repeater 50 that has confirmed that the central wireless base station 68 contains sensor information of this type will always switch to a receiving standby state.

[0080] Furthermore, if additional wireless access points 68 are installed at a later time, the newly installed wireless access points 68 will be activated at predetermined transmission time intervals (for example, every 10 minutes) and will repeatedly transmit an advertised signal to the repeater 50 or the higher-level device 80, thereby establishing a connection when the repeater 50 enters a receiving standby state (Figure 11).

[0081] On the other hand, if the connection between the wireless access point 68 and the repeater 50 is interrupted after the connection has been established, the repeater 50 issues an ACK to the other wireless access point 68 under its control, along with information about the interrupted access point (address, startup time), and instructs the repeater 50 to relay the wireless transmission from that access point 68 (Figure 12).

[0082] Upon receiving the command, the wireless base station 68 enters a receiving standby state based on the above information, in accordance with the startup time of the wireless base station 68 whose connection has been interrupted, and hops the information from the said wireless base station 68 to the repeater 50 (Figure 13).

[0083] Figures 12 and 13 show an example where, if the connection between the repeater 50 and the first wireless access point 68 is interrupted, a command is issued to the fourth wireless access point 68 to relay the wireless transmission from the first wireless access point 68, and the information from the first wireless access point 68 is hopped back to the repeater 50.

[0084] In this case, the repeater 50 may use a function to detect at least one of the wireless signal strength and wireless direction, and may prioritize issuing the above command to the wireless base station 68 that is closer to the wireless base station 68 whose connection has been cut off.

[0085] In this manner, if the repeater 50 loses connection with any of the wireless base stations 68 with which communication has been established, when it receives a signal transmission from a different wireless base station 68 with which communication has been established, it transmits information about the wireless base station 68 with which the connection was lost as a response signal to that wireless base station 68, and also instructs that wireless base station 68 to switch to a receiving standby state in accordance with the timing when the wireless base station 68 with which the connection was lost transmits a signal, and to transmit the transmission data received from the wireless base station 68 with which the connection was lost to the repeater 50.

[0086] Furthermore, the wireless access point 68 that issues commands from the repeater 50 may, based on wireless signal strength and direction detection function (implemented in BLE 5.1 ​​and later), prioritize issuing commands to wireless access point 68 located near the wireless access point 68 whose connection has been cut off.

[0087] When using cellular LTE-M for data transmission, various information is transmitted to the higher-level device 80 via the base station 110.

[0088] In this case, the repeater 50 is not required, so the repeater 50 does not perform data transmission aggregation control for each wireless base station 68, but the transmission method on the wireless base station 68 side is the same as that of BLE.

[0089] Furthermore, when transmitting large amounts of data, such as visible image data (VGA JPEG quality 10, 12KB), multiple transmissions are performed using data splitting, but the control described above remains the same.

[0090] The power control unit includes a clock generation unit, a real-time clock, or a counter.

[0091] When the detector and relay are in standby mode, only the clock generation unit, the real-time clock, or the counter of the power control unit operates.

[0092] As described above, according to the monitoring system of the embodiment of the present invention, a plurality of intrinsically safe explosion-proof detection systems, including a plurality of detectors, a wireless master unit, a power supply unit, a transmission cable unit, and a controller, are used to monitor the environmental information in the outdoor tank storage facility or to detect the predetermined abnormality. This makes it possible to monitor the outdoor tank storage facility with a simple configuration.

[0093] Furthermore, if the repeater loses connection with any of the established wireless access points, it will transmit information about the lost access point as a response signal to the lost access point when it receives a signal transmission from a different established access point. The repeater will also instruct the lost access point to switch to a receiving standby state in sync with the timing of the lost access point's signal transmission and to transmit the received data to the repeater. This ensures that even if the connection between the repeater and the wireless access point is lost, the digital signal from the detector can still be transmitted to the higher-level device.

[0094] Furthermore, the repeater has a preset time interval for when it enters a receiving standby state, which is synchronized with the transmission time interval of the advertisement signal transmitted wirelessly from the wireless base station. By repeatedly performing power control that turns off the power outside of the receiving standby state, it is possible to establish communication with each wireless base station while keeping power consumption down.

[0095] Furthermore, it is possible to promote smart security for outdoor tank storage facilities by utilizing IoT and big data to predict hazards and detect disasters early.

[0096] Furthermore, it becomes possible to provide an IoT sensor system that satisfies the unique characteristics of outdoor tank storage facilities (constraints related to intrinsically safe explosion-proof structures, long-distance transmission) while having low maintenance costs (battery replacement, maintenance, etc.).

[0097] Furthermore, by supplying power to multiple detectors from the power supply unit via signal transmission lines, the number of power supply units can be reduced, thereby lowering the management costs of the power supply units.

[0098] Furthermore, by having the detector and wireless master unit each perform wireless communication using the frequency band of specified low-power radio and transmit and receive digital signals using the cable section, a highly reliable intrinsically safe explosion-proof detection system can be provided with a simple configuration.

[0099] Furthermore, it enables low-cost fire / abnormal temperature monitoring in the most technically demanding hazardous areas (ZONE 0).

[0100] <Variation> It should be noted that the present invention is not limited to the embodiments described above, and various modifications and applications are possible without departing from the spirit of the invention.

[0101] For example, the monitoring system 1 may be installed on an outdoor storage tank 300 with an internal floating lid in an outdoor tank storage facility (Figure 14). In this case, since there is not enough light source, monitoring with a visible image camera as described in the above embodiment is difficult. Therefore, a detector 10 can be installed on the floating roof 300A, and a tilt sensor or leak sensor connected to the detector 10 can be used to monitor environmental information of the floating roof 300A or to detect a predetermined abnormality (for example, an abnormal tilt) (Figure 15).

[0102] Furthermore, the monitoring system may be applied to remote inspections of fire extinguishing equipment and instruments installed on the floating roofs of floating roof tanks or underground floating roof tanks in outdoor tank storage facilities. For example, at least one detector in an intrinsically safe explosion-proof detection system may be installed in conjunction with a fire extinguishing agent storage tank located on an outdoor tank storage facility, and may monitor the temperature, internal pressure, or liquid level of the fire extinguishing agent storage tank as environmental information. In this case, the detector can be activated at predetermined arbitrary time intervals (3 hours to 1 day / time) to sense the pressure, liquid level, and temperature of the fire extinguishing agent tank and transmit the information to a higher-level device.

[0103] Furthermore, at least one detector in the intrinsically safe explosion-proof detection system may be installed on the containment dike of an outdoor tank storage facility and may monitor for specified abnormalities such as hazardous material leakage, fire, rainwater accumulation, or temperature anomalies.

[0104] Furthermore, the monitoring system may be configured to use multiple intrinsically safe explosion-proof detection systems to monitor environmental information in an outdoor tank storage facility or to detect predetermined abnormalities. Specifically, as shown in Figure 16, the monitoring system 400 comprises multiple intrinsically safe explosion-proof detection systems 410, a host device 80, and a base station 110. As shown in Figure 17, the intrinsically safe explosion-proof detection system 410 comprises a detector 412, an acquisition unit 414, a power supply unit 416, a transmitting / receiving unit 418, a periodic storage unit 420, a power control unit 422, and a sensor information storage unit 424. The acquisition unit 414 acquires sensor information detected by the sensor. The detector 412 monitors environmental information or determines whether a predetermined abnormality has been detected. The transmitting / receiving unit 418 converts the monitoring result or determination result from the detector 412 into a digital signal and transmits the digital signal to the host device 80 via wireless communication. The periodic memory unit 420 stores predetermined monitoring or detection cycles for each type of environmental information or predetermined abnormality. The power supply unit 416 supplies power. The power supply control unit 422 controls the power supply from the power supply unit 416 according to the monitoring or detection cycle corresponding to the environmental information or predetermined abnormality type. The sensor information storage unit 424 stores threshold values ​​for detecting a predetermined abnormality for each predetermined abnormality type. Multiple intrinsically safe explosion-proof detection systems 410 are installed on the floating roof of the outdoor storage tank or on the top of the tank wall of the outdoor storage tank. [Explanation of Symbols]

[0105] 1. Monitoring System 10 detectors 50 Repeaters 52 Short-range wireless modules 54 Controllers 56 Power supply section 60 Gateways 62 Short-range wireless modules 64 LTE wireless modules 66 Controllers 68 Wireless access point 70 Barriers 72 Controllers 74 Power supply section 76 Transmitters 80 Higher-level equipment 82 Host Computer 86 Control Panel 88 Wireless Transceiver 90 Cable section 100 Intrinsically Safe Explosion-Proof Detection Systems 110 base station 200 Floating roof tanks 200A, 300A floating roof 200B Tank wall 300 Outdoor Storage Tanks 761 LTE Wireless Module 762 Short-range wireless module

Claims

1. A detector that monitors environmental information or determines whether a predetermined abnormality has been detected based on sensor information detected by the sensor, and outputs it as a digital signal, A master unit that aggregates the digital signals acquired by each of the aforementioned detectors and transmits the signals to a higher-level device, A power supply unit that supplies power to the master unit and the detector, A transmission cable section is provided to connect the detector and the master unit, and includes a signal transmission line for transmitting the digital signal, and also supplies power to the detector from the power supply unit. A power control unit controls the supply of power from the power supply unit to each of the detectors according to a predetermined monitoring cycle or detection cycle for the environmental information or the predetermined type of abnormality in the detector, Includes multiple intrinsically safe explosion-proof detection systems, A monitoring system that uses the aforementioned plurality of intrinsically safe explosion-proof detection systems to monitor environmental information or detect predetermined abnormalities in an outdoor tank storage facility.

2. An acquisition unit that acquires sensor information detected by the sensor, A detector that monitors environmental information or determines whether or not a predetermined abnormality has been detected, A transmitting and receiving unit that converts the monitoring result or determination result from the detector into a digital signal and transmits the digital signal to a higher-level device via wireless communication, A period storage unit that stores predetermined monitoring or detection periods for each of the aforementioned environmental information or predetermined types of abnormalities, The power supply unit that provides electricity, A power control unit controls the supply of power from the power supply unit according to the monitoring cycle or detection cycle corresponding to the environmental information or the predetermined type of abnormality, Includes multiple intrinsically safe explosion-proof detection systems, A monitoring system that uses the aforementioned plurality of intrinsically safe explosion-proof detection systems to monitor environmental information or detect predetermined abnormalities in an outdoor tank storage facility.

3. At least one of the detectors in the intrinsically safe explosion-proof detection system is installed on the top of the tank wall of the outdoor storage tank in the outdoor tank storage facility. The monitoring system according to claim 1 or 2, which detects an abnormal state of the outdoor storage tank as the predetermined abnormality.

4. The monitoring system according to claim 1 or 2, wherein the sensor is installed such that the monitoring area of ​​the sensor is set on the opposite side of the outdoor storage tank in the outdoor tank storage facility relative to the location where the detector is installed.

5. The aforementioned outdoor tank storage facility is an outdoor storage tank having a floating roof, At least one of the detectors in the aforementioned intrinsically safe explosion-proof detection system is installed on the floating roof. The monitoring system according to claim 1 or 2, which detects an abnormal state of the floating roof as the predetermined abnormality.

6. The aforementioned outdoor tank storage facility is an outdoor storage tank having a floating roof, The aforementioned sensor includes a visible image camera, The aforementioned intrinsically safe explosion-proof detection system is Based on the image acquired by the visible image camera, the inclination of the floating roof is calculated and output as an angle value. The monitoring system according to claim 3, which detects an abnormal state of the floating roof as the predetermined abnormality.

7. The aforementioned outdoor tank storage facility is an outdoor storage tank having a floating roof, As a predetermined abnormality, a ring fire in a floating roof is detected. The sensor includes a flame sensor or a temperature sensor. The monitoring system according to claim 3, wherein the flame sensor or the temperature sensor is arranged such that the monitoring area of ​​the flame sensor or the temperature sensor is set to the circumferential portion of the floating roof.

8. The aforementioned outdoor tank storage facility is an outdoor storage tank having a floating roof, The monitoring system according to claim 3, which detects abnormal conditions of the floating roof, including, as a predetermined abnormality, leakage of hazardous materials, fire, rainwater accumulation, or temperature abnormality.

9. A gateway that converts information transmitted from each of the multiple intrinsically safe explosion-proof detection systems into a protocol used by the higher-level device, A relay device that relays transmissions between the master unit and the gateway of each of the plurality of intrinsically safe explosion-proof detection systems, It further includes, The monitoring system according to claim 1, wherein each of the gateway and the repeater performs wireless signal transmission.

10. The power control unit includes a clock generation unit, a real-time clock, or a counter. When the detector and relay are in standby mode, only the clock generation unit, the real-time clock, or the counter of the power control unit operates. The monitoring system according to claim 1 or 2.

11. The aforementioned sensor is one or more of the following: infrared sensor, temperature sensor, vibration sensor, thermocouple, tilt sensor, flame sensor, visible image camera, night vision thermocouple, digital pressure sensor, Bourdon tube pressure indicator reading sensor, leak sensor, and ToF (Time Of Flight) sensor. The monitoring system according to claim 1 or 2.

12. At least one of the intrinsically safe explosion-proof detection systems is installed in conjunction with the fire extinguishing agent storage tank located on the outdoor tank storage facility. The aforementioned environmental information includes monitoring the temperature, internal pressure, or liquid level of the fire extinguishing agent storage tank. The monitoring system according to claim 1 or 2.

13. At least one of the detectors in the aforementioned intrinsically safe explosion-proof detection system is installed on the containment dike of the outdoor tank storage facility. The monitoring system according to claim 1 or 2, which monitors for the aforementioned predetermined abnormalities, such as leakage of hazardous materials, fire, rainwater accumulation, or temperature abnormalities.

14. The aforementioned repeater is, The monitoring system according to claim 9, wherein a time interval in which the repeater itself enters a receiving standby state is set in advance to match the transmission time interval of the advertisement signal wirelessly transmitted from the master unit, and power control is repeatedly performed to turn off the power outside of the receiving standby state, thereby establishing communication with the master unit.

15. When the repeater receives transmission signals from multiple master units with established communication, it aggregates the timing of signal transmission from each master unit by individually specifying the next data transmission time for each master unit. The monitoring system according to claim 14.

16. A gateway that converts information transmitted from each of the multiple intrinsically safe explosion-proof detection systems into a protocol used by the higher-level device, A relay device that relays transmissions between the master unit and the gateway of each of the plurality of intrinsically safe explosion-proof detection systems, It further includes, The aforementioned repeater is, If the connection with any of the established master units is interrupted, when a signal transmission is received from a different established master unit, the information of the master unit whose connection was interrupted is transmitted to that master unit as a response signal, The monitoring system according to claim 1, wherein the master unit transitions to a receiving standby state in conjunction with the timing at which the master unit whose connection has been interrupted transmits a signal, and issues a command to the repeater to transmit the transmission data received from the master unit whose connection has been interrupted.

17. The repeater uses a function to detect at least one of the radio signal strength and radio signal direction, and prioritizes issuing the command to the base station with the highest radio signal strength when the connection to the base station has been cut off. The monitoring system according to claim 16.

18. The aforementioned repeater is, The monitoring system according to claim 16, wherein when a new master unit is installed, the system establishes a connection with the new master unit by receiving an advertisement signal transmitted by the new master unit at predetermined time intervals when it enters a receiving standby state.

19. The aforementioned monitoring system A monitoring system according to claim 1 or 2, which uses Bluetooth Low Energy, LoRaWAN, specified low-power radio, Wi-SUN, or Wi-Fi as a wireless transmission standard.

20. A detector that monitors environmental information or determines whether a predetermined abnormality has been detected based on sensor information detected by the sensor, and outputs it as a digital signal, A master unit that aggregates the digital signals acquired by each of the aforementioned detectors and transmits the signals to a higher-level device, A power supply unit that supplies power to the master unit and the detector, A transmission cable section is provided to connect the detector and the master unit, and includes a signal transmission line for transmitting the digital signal, and also supplies power to the detector from the power supply unit. A power control unit controls the supply of power from the power supply unit to each of the detectors according to a predetermined monitoring cycle or detection cycle for the environmental information or the predetermined type of abnormality in the detector, Multiple intrinsically safe explosion-proof detection systems, A gateway that converts information transmitted from each of the multiple intrinsically safe explosion-proof detection systems into a protocol used by the higher-level device, A relay device that relays transmissions between the master unit and the gateway of each of the plurality of intrinsically safe explosion-proof detection systems, Includes, The aforementioned repeater is, If the connection with any of the established master units is interrupted, when a signal transmission is received from a different established master unit, the information of the master unit whose connection was interrupted is transmitted to that master unit as a response signal, The master unit switches to a receiving standby state in conjunction with the timing when the master unit whose connection has been interrupted transmits a signal, and issues a command to the repeater to transmit the transmission data received from the master unit whose connection has been interrupted. A monitoring system.

Images