JP7123553B2 - Blocking/opening system for piping members and blocking/opening method for piping members - Google Patents

Description

TECHNICAL FIELD The present invention relates to a system and a method for shutting off or opening piping members using advance information such as J-alert, emergency warning broadcast, and earthquake early warning.

A system is known in which an emergency cutoff valve is closed after an earthquake has occurred and an abnormality such as shaking has been detected (see Patent Documents 1 and 2).

JP-A-2000-213700 JP 2014-74307 A

Patent Literature 1 described above describes a technique of comparing the intensity of an earthquake detected by an earthquake sensor with a set intensity and shutting off an emergency shutoff valve if the intensity is greater than or equal to the set intensity. In addition, Patent Document 2 describes a technique for determining whether or not a shutoff valve installed in a water reservoir needs to be closed based on an earthquake intensity and a water level when an earthquake is detected by an earthquake detection and measurement unit. It is However, in order to prevent damage due to an earthquake, there is a problem that it is desirable to close the emergency shutoff valve before a disaster actually occurs, that is, before an abnormality is detected by a sensor or the like.

In general, advance information such as J-alert, emergency warning broadcasts, and earthquake early warnings are broadcast before a disaster. Therefore, the inventors of the present invention focused on controlling the emergency cutoff valve using these broadcasts. Furthermore, even if such advance information is received, the emergency shutoff valve may not actually be closed due to some trouble. In order to cope with such a case, it is desirable to have a double control mechanism for opening and closing the emergency cutoff valve.

In view of these problems, it is an object of the present invention to provide a piping member blocking/opening system and a piping member blocking/opening method that are highly convenient.

In order to achieve the above object, the shutoff/opening system of the present invention comprises receiving means for receiving pre-disaster information transmitted to the public; and at least one of emergency shutoff valve control means for opening the emergency shutoff valve of a predetermined piping member, and detecting an earthquake, and in response to the detection, whether the predetermined emergency shutoff valve has been shut off earthquake detection means for confirming whether or not a predetermined emergency release valve has been opened , wherein the earthquake detection means is installed near the predetermined emergency shutoff valve or the predetermined emergency release valve, and the The first feature is to detect P waves of earthquakes .

Also, in the cut-off and release system of the present invention, in the first feature, the second feature is that the disaster pre-disaster information is at least one of J-alert, emergency warning broadcast, and earthquake early warning.

Further, in the shut-off/open system of the present invention, in the first characteristic or the second characteristic, the emergency shut-off valve control means shuts off a predetermined emergency shut-off valve when it is not shut off. and

Further, in the shutoff/opening system of the present invention, in the first characteristic or the second characteristic, the emergency opening valve control means, in the fourth characteristic, opens a predetermined emergency opening valve when it is not opened. and

Further, in the blocking and opening system of the present invention, in the first characteristic, the fifth characteristic is that the earthquake detection means is a seismic sensor or an earthquake detector.

Further, in the shutoff/opening method for piping members of the present invention, pre-disaster information that is publicly transmitted is received, and when the pre-disaster information is received, a predetermined valve of the piping member is at least either shut off or opened. , detecting an earthquake, confirming whether a predetermined emergency shutoff valve has been shut off or whether a predetermined emergency opening valve has been opened according to the detection, and determining whether the predetermined emergency shutoff valve or the predetermined emergency opening A sixth feature is to detect the P wave of the earthquake near the valve .

According to the present invention, prior information such as J-alert, emergency warning broadcast, earthquake early warning, etc. is used to shut off or open the piping member, and furthermore, in the event that the emergency shut-off valve is not actually closed due to some trouble, or Providing a highly convenient system for shutting off and opening piping members and a method for shutting off and opening piping members by controlling the opening and closing of emergency shutoff valves in a double manner so that it can be handled even when the emergency open valve is not opened. It becomes possible to

1 is a system configuration diagram of a blocking/opening system 1 and a blocking/opening system 2 according to an embodiment of the present invention; FIG. 1 is a configuration block diagram of a cutoff/opening device 60 according to an embodiment of the present invention; FIG. It is a flow chart figure of interception opening system 1 in an embodiment of the invention. It is a flow chart figure of interception opening system 2 in an embodiment of the invention.

The present invention will be described in more detail below using preferred embodiments. However, the following embodiments are merely examples embodying the present invention, and the present invention is not limited thereto.

FIG. 1 is a system configuration diagram of a piping member blocking/opening system 1 and a blocking/opening system 2 according to an embodiment of the present invention. The piping member shut-off system 1 and the shut-off system 2 are systems that are attached to piping members installed in factories, facilities, etc., and are composed of at least a shut-off device 60 and a piping member. The communication terminal 10 is used for outputting notifications from the cutoff/opening device 60 and for receiving advance information such as an earthquake early warning, and is desirably included in this system.

The piping member is a member for flowing liquid or gas inside, and may be, for example, a pipe 5, a valve 50, a joint (not shown), or a flange (not shown). Piping members to which the present invention is applicable may include tanks 1000 for storing liquids or gases.

The valve 50 is a device or instrument for manually or automatically adjusting the flow rate of liquid or gas flowing inside, for example, a ball valve, a diaphragm valve, a gate valve, a butterfly valve, a regulating valve, an automatic flow control valve, an automatic Examples include, but are not limited to, pressure control valves, check valves, stop valves, constant flow valves, solenoid valves and pinch valves. The valve 50 is an automatic valve that automatically opens and closes the valve by receiving a predetermined signal and automatically adjusts the degree of opening of the valve. The automatic valve may be either an air type in which the valve for adjusting the flow rate is driven by air, an electric type in which the valve is electrically driven, or an electromagnetic type in which the valve is driven by an electromagnet.

The material of the valve 50 is not particularly limited, but is preferably a resin such as polypropylene (PP), polyethylene (PE), polyvinyl chloride (PVC), chlorinated polyvinyl chloride (PVC-C), polystyrene. (PS), polycarbonate (PC), acrylonitrile butadiene styrene resin (ABS resin), polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), polyphenylene oxide (PPO), polyphenylene ether (PPE), tetrafluoroethylene A perfluoroalkyl vinyl ether copolymer (PFA) or the like can be used. Polyvinyl chloride (PVC) also includes rigid polyvinyl chloride and rigid impact resistant polyvinyl chloride. Also, a rubber material such as ethylene propylene rubber, fluororubber, or polytetrafluoroethylene may be partially used for the sealing portion.

The shut-off device 60 is fixedly installed on a piping member (the valve 50 and the tank 1000 in the example of FIG. 1), and various sensors, an open switch 40 and a close switch 41 are communicably connected. The shut-off device 60 can open and close the valve 50 by transmitting predetermined signals to the open switch 40 and the close switch 41 via the external input/output unit 64. Or it shall be possible to adjust the gas flow rate. For example, when the valve 50 is a ball valve, opening and closing of the valve 50 is performed by rotating the valve. Therefore, the degree of opening of the valve is determined by the rotation speed and rotation time. The control unit of the automatic valve can determine the actual degree of opening based on this rotation speed and rotation time. It is also possible to cut off completely. In addition, it is desirable that the shutoff/opening device 60 and the valve opening/closing mechanism of the valve 50 are equipped with a self-power source such as a battery so that they can operate even in the event of a power failure.

FIG. 2 is an electrical configuration block diagram of the cut-off device 60. As shown in FIG. In the blocking/opening system 1, the blocking/opening device 60 includes a control unit 61 for controlling various data, a storage unit 62 for storing various data, an external input/output unit 64 connected to various sensors and the like, and a communication terminal 10. and a wireless communication unit 65 that performs wireless communication, a receiving unit 66 that receives pre-disaster information that is publicly broadcast, and when the receiving unit 66 receives the pre-disaster information, cut off the emergency shutoff valve of a predetermined piping member and an emergency open valve control unit 69 for opening the emergency open valve of a predetermined piping member. In the blocking/opening system 2 , the blocking/opening device 60 is further provided with an earthquake detection unit 68 that detects an earthquake based on the signal from the seismic sensor 34 .

The control unit 61 may be a microcomputer, a CPU (Central Processing Unit), a programmable controller (PLC), a RAM (Random Access Memory), a ROM (Read Only Memory), etc., which perform arithmetic control of various data, and Data may be transmitted and received through a communication line network such as the Internet, and the calculation itself may be performed by a host computer or a server.

The storage unit 62 may be a memory, hard disk, or the like to which various data can be written, or may be stored in a network server through a communication network such as the Internet.

Various sensors such as the seismic sensor 34 and the open switch 40 and the close switch 41 are communicatively connected to the external input/output unit 64 . The external input/output unit 64 includes, for example, analog-to-digital conversion (ADC), digital-to-analog conversion (DAC), a comparator for isolation conversion, an analog input/output circuit (AIO), an amplifier circuit (AMP), and a pulse modulation circuit. (PWM), serial communication port (SIO), USB circuitry, and the like. Further, a function for outputting sound, light, characters, or the like may be provided.

In order to perform wireless communication with the communication terminal 10, the wireless communication unit 65 is a device for realizing communication such as WiFi (Wireless Fidelity), Bluetooth (registered trademark), Hart, ISA100, Zigbee, for example, BLE (Bluetooth Low Energy ) module communication kit.

The receiving unit 66 is a device for receiving pre-disaster information that is publicly broadcast. Pre-disaster information here means at least one of J-alert, emergency warning broadcast, and earthquake early warning. In FIG. 2, the receiving unit 66 is configured to directly receive the public broadcast, but the communication terminal 10 may receive the disaster pre-disaster information and notify the receiving unit 66 of the information via the wireless communication unit 65. .

The emergency shutoff valve control unit 67 shuts off the emergency shutoff valve of a predetermined piping member when the receiving unit 66 receives the pre-disaster information.
An emergency shutoff valve is a valve that shuts off a valve that is mainly open during normal use in an emergency. The emergency shutoff valve is a valve that is set in advance to shut off in an emergency, but depending on the type of fluid and usage conditions, it may not shut off completely and may be in a slightly open state. The emergency shut-off valve is a valve used, for example, in a water storage tank (for drinking) on the roof of a building, and is shut off in order to secure drinking water in an emergency.

The emergency open valve control unit 69 opens the emergency open valve of a predetermined piping member when the receiving unit 66 receives the pre-disaster information.
An emergency open valve is a valve that is used to forcibly open a normally closed valve in an emergency. An emergency open valve is a valve that is set in advance to be opened in an emergency. For example, it is used to forcibly discharge dangerous liquids such as chemical treatment tanks and reaction tanks from separate pipes, and when normal sewage drainage treatment cannot be done in time due to torrential rain, etc., it is a valve that guides to the rainwater tank in the basement of the building. used.

For example, when the valve 50 is an emergency shutoff valve, when the receiving unit 66 receives the disaster prior information, the emergency shutoff valve of the valve 50 is controlled via the external input/output unit 64 to shut off the valve 50. . On the other hand, when the valve 50 is an emergency open valve, when the receiving unit 66 receives the disaster prior information, the emergency open valve of the valve 50 is controlled via the external input/output unit 64, and the valve 50 is opened. . In addition, for the received pre-disaster information, you can register in advance at what level emergency shut-off valve control and emergency open valve control are to be performed. It may be set so that the emergency shutdown or opening process is performed only in the case. That is, information such as the level of the disaster, the seismic intensity, and the area may be received from the pre-disaster information, and whether to perform the blocking process or the opening process may be determined according to the contents.

The earthquake detector 68 detects an earthquake based on the signal from the seismic sensor 34 . Alternatively, instead of the seismic sensor 34, a seismic sensor (not shown) may be provided. The earthquake detection unit 68 detects whether or not an earthquake has actually occurred, and if detected, determines whether the valve of the valve 50 has been shut off (if the valve 50 is an emergency shutoff valve) via the external input/output unit 64. ) is confirmed, and if it is not shut off, the emergency shutoff valve control unit 67 shuts off the valve 50 .
On the other hand, for the emergency opening valve, the earthquake detection unit 68 detects whether or not an earthquake has actually occurred. If the valve 50 is an emergency open valve), and if it is not open, the emergency open valve control unit 69 performs an opening process for the valve 50 .

The sensor is a device for detecting information about piping members, and for example, a temperature sensor 33 that measures the temperature inside the valve 50, the surrounding environment, flowing gases and liquids, underground, etc., and a humidity sensor that measures the humidity of the environment and soil. sensor (not shown), liquid leakage sensors 31 and 74 for detecting liquid leakage inside and outside the valve, pressure sensor (not shown) for measuring the pressure and impact pressure of flowing gas or liquid, atmospheric pressure sensor (not shown), A strain sensor 30 (realized by a load sensor, a multi-axis sensor, an angle sensor, an acceleration sensor, etc.) that detects the strain of the piping member, a vibration sensor (not shown) that detects the vibration of the piping member, and a flow rate sensor that measures the flow rate and flow velocity. (not shown), rotation angle, flow velocity, pulse sensor (not shown) for measuring PWM modulation, limit switch (not shown) for detecting opening/closing position, position detection sensor (not shown) for detecting opening/closing angle ), a densitometer (not shown) for measuring liquid concentration, a pH meter sensor 71 for measuring pH of flowing liquid or surrounding environment, a gas detection sensor (not shown) for measuring flowing gas or surrounding environment, and measuring ultraviolet intensity. a UV illuminance sensor 70 for detecting brightness, an illuminance sensor (not shown) for detecting brightness, a magnetic sensor (not shown), an infrared sensor (not shown) for detecting a human body or an obstacle, an optical sensor (not shown) for detecting nighttime (not shown), a flame sensor (not shown) to detect fire, a touch sensor (not shown) to detect contact, a microphone sound sensor (not shown) to detect the sound of flowing liquid and noise, and non-destructive measurement. An ultrasonic sensor (not shown) for detecting light, an optical sensor 73 for detecting light, a liquid level sensor 75 for detecting the amount of liquid, a soil analysis sensor 32 for analyzing water quality of soil, and the like may be used.

The installation location of the sensor is not particularly limited as long as it can collect the desired data, but it may be installed inside or on the outer periphery of the valve body, or may be installed in the vicinity of the valve. Alternatively, it may be installed in a piping member other than the valve. As shown in FIG. 1, the strain sensor 30, the liquid leakage sensor 31, the temperature sensor 33, and the pressure sensor 35 are installed on the piping member, for example, the valve 50, and the temperature sensor 33 and the vibration sensor 34 are installed on the pipe 5. be done. The UV illuminance sensor 70 is installed above the tank 1000 and piping members (where the sun shines), the PH meter sensor 71 and the temperature sensor 33 are installed inside the tank 1000, and the liquid level sensor 75 is installed inside the tank 1000. Located inside and at the liquid surface, the optical sensor 73 is located inside the tank 1000 and at the bottom of the tank 1000 . The soil analysis sensor 32 is installed inside the soil below where the piping member is located near the valve 50 .

The communication terminal 10 is a terminal capable of wireless communication with at least the shutoff/opening device 60, and has an input unit that receives an operation input such as a touch from an operator, and an emergency shutoff valve shutoff process or an emergency open valve open process. A display unit for outputting results and the like or an output unit for outputting audio is provided. The communication terminal 10 may be a computer terminal, smart phone, or tablet terminal. Also, although not shown, the communication terminal 10 may be connected to another communication terminal or a control system to exchange data from the communication terminal 10 with each other.

FIG. 3 is a flow chart of the blocking/opening system 1 according to the embodiment of the present invention. The receiving unit 66 of the cutoff/release device 60 periodically checks whether or not the pre-disaster information has been received (step S301). The periodical check interval may be about 0.5 seconds to 60 seconds, but the shorter the interval, the more it is possible to cut off or open in real time when a disaster occurs. Here, the pre-disaster information is at least one of J-alert, emergency warning broadcast, and earthquake early warning.

If the pre-disaster information has not been received, the process of step S301 is continued.

When the pre-disaster information is received, the emergency shutoff valve control unit 67 performs processing to shut off the emergency shutoff valves of predetermined piping members via the external input/output unit 64 (step S302). In the example of FIG. 1, if the valve of the valve 50 is an emergency shutoff valve, this valve is controlled to shut off the valve 50 . In addition, for the received pre-disaster information, the level at which the emergency shutoff valve control is to be performed is registered in advance. Emergency shutdown processing may be performed.

In addition, when pre-disaster information is received, the emergency release valve control unit 69 performs processing to open the emergency release valves of predetermined piping members via the external input/output unit 64 (step S303). In the example of FIG. 1, if the valve of the valve 50 is an emergency open valve, this valve is controlled and the opening process of the valve 50 is performed. In addition, for the received pre-disaster information, the level at which the emergency opening valve control is to be performed is registered in advance. An emergency opening process may be performed.

In the above-described shut-off/open system 1, the method of receiving the pre-disaster information and shutting off/opening the piping members according to the information has been described. With this shut-off and open system 1, it is possible to close the emergency shut-off valve and open the emergency open valve before a disaster actually occurs, that is, before an abnormality is detected by a sensor or the like. damage can be minimized.

However, a mechanism that double-controls the opening and closing of the emergency shut-off valve and the emergency open valve so that it can be handled in the event that the emergency shut-off valve is not closed or the emergency open valve is not opened due to the disaster information in advance due to some trouble. It is desirable to have In the following, in addition to the configuration of the blocking/opening system 1, a blocking/opening system 2 that further includes an earthquake detection unit 68 in the blocking/opening device 60 will be described.

FIG. 4 is a flow chart of the blocking/opening system 2 according to the embodiment of the present invention. The receiving unit 66 of the cutoff/release device 60 periodically checks whether or not the pre-disaster information has been received (step S401). The periodical check interval may be about 0.5 seconds to 60 seconds, but the shorter the interval, the more it is possible to cut off or open in real time when a disaster occurs. Here, the pre-disaster information is at least one of J-alert, emergency warning broadcast, and earthquake early warning.

If the pre-disaster information has not been received, the process of step S401 is continued.

When the pre-disaster information is received, the emergency shutoff valve control unit 67 performs processing to shut off the emergency shutoff valve of the predetermined piping member via the external input/output unit 64, and the emergency open valve control unit 69 , a process of opening the emergency open valve of a predetermined piping member via the external input/output unit 64 (step S402).

The earthquake detection unit 68 of the cutoff/opening device 60 periodically checks whether or not an earthquake has been detected (step S403). The earthquake detector 68 detects an earthquake based on signals from the seismic sensor 34 or an earthquake detector (not shown). Here, earthquakes may be P waves or S waves, but it is desirable to detect P waves.

In the flowchart of FIG. 4, for convenience of explanation, the process of step S403 is performed after step S401. , may be performed in parallel.

If no earthquake has been detected, the process of step S403 is continued.

When an earthquake is detected, it is confirmed through the external input/output unit 64 whether or not the emergency shutoff valves of the predetermined piping members have been shut off (step S404). In the example of FIG. 1, if the valve 50 is an emergency shutoff valve, it is checked whether the valve 50 has been shut off.

In step S404, if the emergency shutoff valve of the predetermined piping member has not been shut off, the emergency shutoff valve control unit 67 performs processing to shut off the emergency shutoff valve of the predetermined piping member via the external input/output unit 64. (step S405).

If the shutoff process in step S405 is successful, the communication terminal 10 is notified that the emergency shutoff valve has been shut off after the earthquake detection by the earthquake detector 68 (step S406). At the same time, it is also possible to output sound, light, characters, etc. to the external input/output unit 64 of the shutoff/opening device 60 so that the surrounding people know that the emergency shutoff valve has been shut off after the earthquake is detected. .

In step S404, when the emergency shutoff valve of the predetermined piping member has been shut off, the communication terminal 10 is notified that the emergency shutoff valve has been shut off before the earthquake detection by the earthquake detection unit 68 (step S407). ). At the same time, it is also possible to output sound, light, text, etc. to the external input/output unit 64 of the shutoff/opening device 60 so that the surrounding people know that the emergency shutoff valve has been shut off before the earthquake is detected. .

Then, similarly, the processing of the emergency release valve follows. When an earthquake is detected, it is checked through the external input/output unit 64 whether or not the emergency release valves of the predetermined piping members have been opened (step S408). In the example of FIG. 1, if the valve 50 is an emergency open valve, it is checked whether the valve 50 has been opened.

In step S408, if the emergency open valve of the predetermined piping member has not been opened, the emergency open valve control unit 69 performs processing to open the emergency open valve of the predetermined piping member via the external input/output unit 64. (step S409).

If the opening process in step S409 is successful, the communication terminal 10 is notified that the emergency opening valve has been opened after the earthquake detection by the earthquake detection unit 68 (step S410). At the same time, it is also possible to output sound, light, characters, etc. to the external input/output unit 64 of the shutoff/opening device 60 so that people around can know that the emergency opening valve has been opened after the earthquake is detected. .

In step S408, if the emergency release valve of the predetermined piping member has already been opened, the communication terminal 10 is notified that the emergency release valve has been opened before the earthquake detection by the earthquake detection unit 68 (step S411). ). At the same time, sound, light, text, or the like may be output to the external input/output unit 64 of the shutoff/opening device 60 so that people in the vicinity know that the emergency opening valve has been opened before the earthquake is detected. .

In the flowchart of FIG. 4, an example of notifying the communication terminal 10 after detecting an actual earthquake in step S403 is described. is performed, notification to the communication terminal 10 and output to the external input/output unit 64 may be performed in the same manner. Also, if at least one of the blocking process in step S405 and the opening process in step S409 fails, the communication terminal 10 is notified of the failure and the external input/output unit 64 is notified of the failure by sound, light, text, or the like. You can output.

Further, although an example in which an earthquake is actually detected as an anomaly by the earthquake detection unit 68 is shown here, an anomaly other than an earthquake may be detected. In order to detect anomalies other than earthquakes, such as fire, flooding, damage due to deterioration, and liquid leakage, data from the above-described sensors may be used to correspond to step S403.

Additionally, the various sensors of FIG. 1 may be used after a disaster strikes. That is, humidity sensors, liquid leakage sensors 31 and 74, pressure sensors, atmospheric pressure sensors, strain sensors 30, vibration sensors, and the like may be used for the purpose of monitoring the state of piping members after a disaster occurs.

In the shut-off system 2 described above, the emergency shut-off valves are closed and the emergency open valves are opened before the disaster actually occurs by receiving prior disaster information and shutting off and opening the piping members accordingly. In addition, in order to cope with the case that the emergency shutoff valve is not closed due to some kind of trouble due to the pre-disaster information or the emergency open valve is not opened due to some trouble, the emergency shutoff valve and the emergency Controls the opening and closing of the release valve. As a result, it is possible to provide a piping member blocking/opening system and a piping member blocking/opening method that are more convenient.

1 Shut-off system 5 Pipe 10 Communication terminal 30 Strain sensor 31 Leakage sensor 32 Soil analysis sensor 33 Temperature sensor 34 Seismic sensor 35 Pressure sensor 40 Open switch 41 Close switch 50 Valve 60 Shut-off device 61 control unit 62 storage unit 64 external input/output unit 65 wireless communication unit 66 reception unit 67 emergency shutoff valve control unit 69 emergency release valve control unit 70 UV illumination sensor 71 PH meter sensor 73 optical sensor 74 liquid leakage sensor, 75 liquid level sensor,
1000 tank

Claims (6)

Receiving means for receiving publically transmitted pre-disaster information;
Emergency shut-off valve control means for shutting off an emergency shut-off valve of a predetermined piping member when receiving the disaster pre-disaster information, and opening an emergency open valve of a predetermined piping member when receiving the disaster pre-disaster information at least one emergency release valve control means;
an earthquake detection means for detecting an earthquake and, in response to the detection, checking whether a predetermined emergency shutoff valve has been shut off or whether a predetermined emergency release valve has been opened ;
The shut-off/open system for piping members , wherein the earthquake detection means is installed near the predetermined emergency shut-off valve or the predetermined emergency open valve and detects the P-wave of the earthquake . 2. The shut-off and release system for piping members according to claim 1, wherein said disaster prior information is at least one of J-alert, emergency warning broadcast, and earthquake early warning. 3. The shut-off system for piping members according to claim 1, wherein said emergency shut-off valve control means shuts off a predetermined emergency shut-off valve when it is not shut off. 3. The shut-off system for piping members according to claim 1, wherein the emergency open valve control means opens a predetermined emergency open valve when it is not open. 2. The shut-off system for piping members according to claim 1, wherein said earthquake detection means is a seismic sensor or an earthquake sensor. A method for shutting off and opening a piping member,
receiving publicly transmitted disaster pre-disaster information;
a step of at least one of closing or opening a predetermined valve of the piping member when the prior disaster information is received;
an earthquake detection step of detecting an earthquake and, in response to the detection, checking whether a predetermined emergency shutoff valve has been shut off or whether a predetermined emergency release valve has been opened ;
The method for shutting off and opening a piping member , wherein the earthquake detecting step detects the P wave of the earthquake near the predetermined emergency shutoff valve or the predetermined emergency open valve .

Images