Nitrogen concentration control device and nitrogen concentration control method

Abstract

It allows for proper control of the indoor atmosphere during emergencies. [Solution] A nitrogen concentration management device for managing the nitrogen concentration of a controlled space in which a nitrogen storage unit is located in which nitrogen is stored at a pressure higher than atmospheric pressure, comprising: a concentration measuring unit for measuring the oxygen concentration or nitrogen concentration of the space; an oxygen supply unit capable of supplying oxygen to the space; and a control device for controlling the supply of oxygen from the oxygen supply unit to the space based on the measurement results of the concentration measuring unit, wherein the oxygen supply unit includes a compressed gas storage unit filled with oxygen-containing gas at a pressure higher than that of the space; a piping unit which is a path for supplying oxygen from the compressed gas storage unit to the space; and a switching unit located in the piping unit which switches whether or not to supply oxygen to the space under the control of the control device.

Description

Technical Field

[0001] The present disclosure relates to a nitrogen concentration management device and a nitrogen concentration management method for managing the nitrogen concentration indoors.

Background Art

[0002] In rooms with high tightness, the exchange of air with the outside air is restricted. When the concentration of a specific gas becomes high in such a room, problems may occur. In Patent Document 1, inside a nuclear power plant building, there are a nuclear reactor pressure vessel, a nuclear reactor containment vessel installed at a predetermined interval on the outer peripheral side of the nuclear reactor pressure vessel, and a small room that communicates through a penetration part from the inside of the nuclear reactor containment vessel and has a smaller volume than the nuclear reactor pressure vessel. A hydrogen countermeasure purge system inside the nuclear power plant building that suppresses the hydrogen concentration leaked from the nuclear reactor containment vessel to the small room is described.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Patent Document 1 reduces the possibility of combustion by reducing the concentration of hydrogen, which is a flammable gas. Here, in facilities such as plants, gases that are not flammable are also used, and they may be stored at high pressure in cylinders such as compressed gas cylinders in a predetermined room. If the cylinder stored inside a predetermined room leaks, work in the predetermined room becomes impossible. Also, when the power supply system in the facility fails, the air conditioning function in the predetermined room stops, so the change in the atmosphere in the predetermined room due to air circulation also does not progress.

[0005] The present disclosure solves the above-described problems, and an object thereof is to provide a nitrogen concentration management device and a nitrogen concentration management method that can appropriately manage the indoor atmosphere in an emergency. [Means for solving the problem]

[0006] To achieve the above objective, the nitrogen concentration control device of the present disclosure is a nitrogen concentration control device for controlling the nitrogen concentration of a space to be controlled, in which a nitrogen storage unit in which nitrogen is stored at a pressure higher than atmospheric pressure is located, and comprises: a concentration measuring unit for measuring the oxygen concentration or nitrogen concentration of the space; an oxygen supply unit capable of supplying oxygen to the space; and a control device for controlling the supply of oxygen from the oxygen supply unit to the space based on the measurement results of the concentration measuring unit, wherein the oxygen supply unit includes a compressed gas storage unit filled with an oxygen-containing gas at a pressure higher than that of the space; a piping unit which is a path for supplying oxygen from the compressed gas storage unit to the space; and a switching unit located in the piping unit which switches whether or not to supply oxygen to the space under the control of the control device.

[0007] Furthermore, the nitrogen concentration management method of the present disclosure is a nitrogen concentration management method for managing the nitrogen concentration of a space to be managed, in which a nitrogen storage unit in which nitrogen is stored at a pressure higher than atmospheric pressure is located, and comprises an oxygen supply unit having a compressed gas storage unit filled with an oxygen-containing gas at a pressure higher than the space, a piping unit which is a path for supplying oxygen from the compressed gas storage unit to the space, and a switching unit located in the piping unit which switches whether or not oxygen is supplied to the space, and comprises a concentration measurement step of measuring the oxygen concentration or nitrogen concentration of the space, and a step of controlling the switching unit to supply oxygen from the compressed gas flow unit to the space if the measured oxygen concentration of the space is below a threshold. [Effects of the Invention]

[0008] According to this disclosure, the sample being measured can be measured more accurately. [Brief explanation of the drawing]

[0009] [Figure 1] Figure 1 is a schematic diagram showing an example of a nitrogen concentration control device according to this embodiment. [Figure 2]Figure 2 is a flowchart showing an example of the operation of a nitrogen concentration control device. [Modes for carrying out the invention]

[0010] Preferred embodiments of the present disclosure will be described in detail below with reference to the drawings. However, these embodiments do not limit the present disclosure, and where there are multiple embodiments, they may be combinations of these embodiments. Furthermore, the components in the embodiments include those readily conceivable by those skilled in the art, those that are substantially identical, and those that are equivalent.

[0011] Figure 1 is a schematic diagram showing an example of the nitrogen concentration control device of this embodiment. The nitrogen concentration control device 10 of this embodiment controls the nitrogen concentration in the first building 12 and maintains an environment in which people can work inside the first building 12.

[0012] The first building 12, which is managed by the nitrogen management device 10, will now be described. The first building 12 has a nitrogen storage section 16 inside. The first building 12 is a room with a ceiling and walls. The first building 12 does not need to be a sealed room; it may be a room with vents, gaps, or windows, but it should not be a room with high ventilation. The first building 12 may be an independent room or a room adjacent to other rooms.

[0013] The nitrogen storage unit 16 supplies nitrogen to the target equipment in which it is used. The nitrogen storage unit 16 includes a nitrogen cylinder 20, a nitrogen supply passage 22, and a nitrogen control valve 24. The nitrogen cylinder 20 is a pressure vessel in which nitrogen is stored at a pressure higher than atmospheric pressure. The nitrogen cylinder 20 is located inside the first building 12. The nitrogen stored in the nitrogen cylinder 20 is nitrogen at a concentration that can be used as an inert gas, and the proportion of gases other than nitrogen is higher than that of the atmosphere. The nitrogen supply passage 22 is a pipe connecting the nitrogen cylinder 20 and the target equipment. The nitrogen supply passage 22 supplies the nitrogen discharged from the nitrogen cylinder 20 to the target equipment. The nitrogen control valve 24 is located in the nitrogen supply passage 22 and controls the amount of nitrogen flowing through the nitrogen supply passage 22 by opening and closing it. In this embodiment, only one nitrogen cylinder 20 of the nitrogen storage unit 16 is shown, but multiple cylinders may be provided. Furthermore, the structure in which the nitrogen storage section 16 stores nitrogen is not limited to a nitrogen cylinder 20, but can be any structure that stores compressed nitrogen.

[0014] The nitrogen concentration control device 10 includes an oxygen supply unit 30, an oxygen concentration measuring device 36, and a control device 40. Some components of the nitrogen concentration control device 10 are located in the second building 14. The second building 14 is a different building from the first building 12. Preferably, the second building 14 is a building that has measures in place to protect against disasters such as earthquakes and fires.

[0015] The oxygen supply unit 30 is a unit capable of supplying oxygen to the first building 12, and supplies oxygen to the first building 12 when predetermined conditions are met. The oxygen supply unit 30 has a plurality of oxygen cylinders 42, a piping section 44, a plurality of cylinder on / off valves 46, and a switching valve 48. The plurality of oxygen cylinders 42 are located in the second building 14. The oxygen cylinders 42 in this embodiment store compressed atmospheric gas. In other words, the oxygen cylinders 42 store gas with an oxygen concentration of approximately 21%. The piping section 44 connects the plurality of oxygen cylinders 42 to the interior of the first building 12. The piping section 44 is a path for supplying oxygen from the oxygen cylinders 42 to the interior of the first building 12. One end of the piping section 44 branches out to correspond to the plurality of oxygen cylinders 42, and each of the plurality of oxygen cylinders 42 is connected in parallel. The other end of the piping section 44 is located inside the first building 12. Cylinder shut-off valves 46 are located at the branching points of the piping section 44 to each oxygen cylinder 42. The cylinder shut-off valves 46 switch the opening and closing of each oxygen cylinder 42. It is preferable that the oxygen cylinders 42 be located in a space different from the first building 12, but they may also be located outside the building.

[0016] The switching valve 48 is positioned between the end of the piping section 44 connected to the oxygen cylinder 42 and the other end. In other words, it is positioned where the oxygen supply paths converge into a single path. By switching the switching valve 48 open and closed, the supply of oxygen to the first building 12 can be started and stopped, that is, the presence or absence of oxygen supply can be switched. In this embodiment, a switching valve 48 is used, but any switching mechanism that switches the supply of oxygen will suffice, and it is not limited to a valve.

[0017] The oxygen concentration measuring device (O2 concentration meter) 36 is located in the first building 12. The oxygen concentration measuring device 36 measures the oxygen concentration inside the first building 12. The oxygen concentration measuring device 36 sends the measured results to the control device 40. The oxygen concentration measuring device 36 is connected to a battery 37 and a grid power supply 50. The battery 37 supplies power to the oxygen concentration measuring device 36 when the power supply from the grid power supply 50 is interrupted. The grid power supply 50 is the power source that drives the facility where the nitrogen concentration management device 10 is installed. If the facility is generating power with a generator, it is the power from the generator; if it is operating on power supplied from another power generation facility, it is the power supplied from an external source.

[0018] The control device 40 switches the opening and closing of the switching valve 48 based on the measurement results of the oxygen concentration measuring device 36. The control device 40 may be an analog circuit that processes the signal of the measurement result from the oxygen concentration measuring device 36 and outputs a control signal to the switching valve 48, or a digital processing device that processes the signal of the measurement result and switches the opening and closing of the switching valve 48. The control device 40 is connected to a battery 41 and a grid power supply 50. The battery 41 supplies power to the control device 40 when the power supply from the grid power supply 50 is interrupted. The control device 40 operates the switching valve 48 by supplying power to a mechanism that switches the opening and closing of the switching valve 48, specifically switching it from a closed state to an open state. The nitrogen concentration management device 10 also connects the switching valve 48 to an independent power source such as a battery, that is, a power source different from the grid power supply 50. Note that the power of the switching valve 48 may be supplied from the battery 41 via the control device 40 or from a separate system.

[0019] Next, the operation of the nitrogen concentration control device will be explained using Figure 2. Figure 2 is a flowchart showing an example of the operation of the nitrogen concentration control device. The nitrogen concentration control device 10 determines whether the power supply has been stopped (step S12). In other words, the nitrogen concentration control device 10 determines whether the power supply from the grid power source 50 has been stopped. If the nitrogen concentration control device 10 determines that the power supply has not been stopped (No in step S12), it returns to step S12.

[0020] When it is determined that the power supply has stopped (Yes in step S12), the nitrogen concentration management device 10 acquires the measurement result of the oxygen concentration (step S14). That is, when a power outage occurs where the power supply from the system power source 50 has stopped, the nitrogen concentration management device 10 acquires the information on the oxygen concentration of the first building 12 measured by the oxygen concentration measuring device 36.

[0021] The nitrogen concentration management device 10 determines whether the measured oxygen concentration is below the threshold value (step S16). That is, the nitrogen concentration management device 10 determines whether the oxygen concentration in the first building 12 has decreased.

[0022] When the nitrogen concentration management device 10 determines that the measured oxygen concentration is not below the threshold value (No in step S16), it returns to step S16. When the oxygen concentration exceeds the threshold value, the nitrogen concentration management device 10 repeats the measurement of the oxygen concentration. Here, the threshold value of the oxygen concentration is preferably 19% or more and 21% or less.

[0023] When the nitrogen concentration management device 10 determines that the measured oxygen concentration is below the threshold value (Yes in step S16), it opens the switching valve 48 (step S18). By opening the switching valve 48, the nitrogen concentration management device 10 supplies the gas containing oxygen from the oxygen cylinder 42 to the first building 12.

[0024] As shown in FIG. 2, when the power supply from the system power 50 stops, that is, when a power loss occurs, the nitrogen concentration management device 10 executes the process, so that even when a nitrogen leak or the like occurs in the first building 12 in a state where power is not supplied and the facilities in the facility including the first building 12 cannot be managed, the inside of the first building 12 can be made into a workable environment. Note that the nitrogen concentration management device 10 may also operate in a state where there is no power loss, and when the oxygen concentration in the first building decreases, the oxygen supply unit 30 may supply oxygen to the first building.

[0025] The nitrogen concentration control device 10 uses an oxygen cylinder 42 that supplies compressed air as the oxygen supply source for the oxygen supply unit 30, so that oxygen supply can be started even in the event of a power outage by opening the switching valve 48. Furthermore, it is preferable that the oxygen supply unit 30 stores an amount of oxygen that will allow people to work in the first building 12 by supplying oxygen from the oxygen cylinder 42 if the entire amount of nitrogen stored in the nitrogen storage unit 16 leaks into the first building 12.

[0026] It is preferable that the nitrogen concentration control device 10 has the end of the piping section 44 on the first building 12 side positioned near the nitrogen storage section 16, specifically, at a location where the oxygen concentration can be maintained at a level sufficient for a person to work in the nitrogen storage section 16, for example, at a distance of 5m or less from the nitrogen storage section 16. This allows for the appropriate supply of oxygen to areas where nitrogen has leaked and the oxygen concentration has decreased (or increased). It is also preferable that the height of the end of the piping section 44 on the first building 12 side of the oxygen supply section 30 is lower than the working height of a person. This allows the oxygen concentration in the work area of ​​the first building 12 to be at an appropriate level. Furthermore, it is preferable that the oxygen concentration measuring device 36 also measures the oxygen concentration at a position lower than the working height of a person.

[0027] The nitrogen concentration control device 10 can be operated during a power outage by supplying batteries 37 and 41 to the oxygen concentration measuring device 36 and the control device 40.

[0028] The nitrogen concentration control device 10 can safely manage the oxygen supply unit 30 by placing the oxygen cylinder 42 in a separate building, the second building 14. It can also switch the cylinder on / off valve 46 on and off without entering the first building 12. Furthermore, by placing the switching valve 48 outside the first building 12, the status of the switching valve 48 can be monitored without entering the first building 12, and in an emergency, the switching valve 48 can be opened from outside the first building 12.

[0029] The nitrogen concentration control device 10 may also use the control device 40 to switch the opening and closing of the cylinder on / off valve 46. The nitrogen concentration control device 10 may also use the control device 40 to switch the opening degree of the switching valve 48. In this way, the nitrogen concentration control device 10 can control the amount of oxygen supplied according to the oxygen concentration, i.e., the nitrogen concentration, of the first building 12.

[0030] In this embodiment, the oxygen concentration measuring device 36 and the control device 40 are connected to the grid power supply 50, but they do not necessarily have to be connected to the grid power supply 50. It is preferable that the nitrogen concentration management device 10 keeps the oxygen concentration measuring device 36 and the control device 40 in a stopped state during normal operation, and activates them only when an abnormal situation occurs. This allows for control of the atmosphere in the first building 12 during normal operation using other functions, and to manage the atmosphere in the first building 12 by activating the nitrogen concentration management device 10 when an abnormal situation occurs.

[0031] In this embodiment, air was supplied from the oxygen supply unit 30, but a gas with a higher oxygen concentration than air may be stored and supplied to the first building 12. This reduces the amount of gas that needs to be supplied to maintain the atmosphere in the first building 12 in a state where people can work. Therefore, the amount of gas stored in the oxygen supply unit 30 can be reduced, and the device can be made smaller.

[0032] In this embodiment, the nitrogen concentration control device 10 measures the oxygen concentration, but it may also be configured to measure the nitrogen concentration instead of the oxygen concentration, calculate the oxygen concentration from the nitrogen concentration, and supply oxygen from the oxygen supply unit 30 when the oxygen concentration falls below a predetermined concentration.

[0033] [Effects of this embodiment] This disclosure has the following characteristics. However, this disclosure is not limited to the following. (1) A nitrogen concentration control device for managing the nitrogen concentration of a space to be managed, wherein a nitrogen storage unit in which nitrogen is stored at a pressure higher than atmospheric pressure is located, comprising: a concentration measuring unit for measuring the oxygen concentration or nitrogen concentration of the space; an oxygen supply unit capable of supplying oxygen to the space; and a control device for controlling the supply of oxygen from the oxygen supply unit to the space based on the measurement results of the concentration measuring unit, wherein the oxygen supply unit comprises: a compressed gas storage unit filled with oxygen-containing gas at a pressure higher than that of the space; a piping unit which is a path for supplying oxygen from the compressed gas storage unit to the space; and a switching unit located in the piping unit which switches whether or not to supply oxygen to the space under the control of the control device.

[0034] (2) The control device opens the switching valve when the oxygen concentration in the space measured by the concentration measuring unit is below a threshold, as described in (1).

[0035] (3) The nitrogen concentration control device according to (1) or (2), wherein the oxygen supply unit is located in a space separate from the space.

[0036] (4) The nitrogen concentration control device according to any one of (1) to (3), wherein the compressed gas storage unit has an amount of oxygen that can maintain the oxygen concentration in the space above a threshold when the nitrogen in the nitrogen storage unit is released into the space.

[0037] (5) The nitrogen concentration control device according to any one of (1) to (4), wherein the concentration measuring unit is driven by an independent power supply, the control device is driven by an independent power supply, and the switching unit is driven by an independent power supply.

[0038] (6) A nitrogen concentration management method for managing the nitrogen concentration of a space to be managed, wherein a nitrogen storage unit in which nitrogen is stored at a pressure higher than atmospheric pressure is located, comprising: a compressed gas storage unit filled with an oxygen-containing gas at a pressure higher than the space; a piping unit which is a path for supplying oxygen from the compressed gas storage unit to the space; and an oxygen supply unit located in the piping unit which switches whether or not oxygen is supplied to the space, the method comprising: a concentration measurement step for measuring the oxygen concentration or nitrogen concentration of the space; and a step of controlling the switching unit to supply oxygen from the compressed gas storage unit to the space if the measured oxygen concentration of the space is below a threshold. [Explanation of Symbols]

[0039] 10. Nitrogen concentration control device 12. Building 1 14. Building 2 16 Nitrogen storage section 20 Nitrogen Cylinders 22 Nitrogen supply channels 24 Nitrogen control valve 30 Oxygen supply unit 32 Compressed gas storage section 34. Supply routes 36. Oxygen concentration measuring device (O2 concentration meter) 37, 41 batteries 40 Control device 42 oxygen cylinders 44 Piping section 46. ​​Cylinder shut-off valve 48 Switching valve 50 Grid power supply

Claims

1. A nitrogen concentration control device for managing the nitrogen concentration in a controlled space where a nitrogen storage section is located, in which nitrogen is stored at a pressure higher than atmospheric pressure, A concentration measuring unit for measuring the oxygen concentration or nitrogen concentration in the aforementioned space, An oxygen supply unit capable of supplying oxygen to the aforementioned space, The system includes a control device that controls the supply of oxygen from the oxygen supply unit to the space based on the measurement results of the concentration measurement unit, The oxygen supply unit includes a compressed gas storage unit filled with oxygen-containing gas at a pressure higher than that of the space, A piping section which is a path for supplying oxygen from the compressed gas storage section to the space, A nitrogen concentration control device comprising a switching unit disposed in the piping section and controlling the presence or absence of oxygen supply to the space by the control device.

2. The nitrogen concentration control device according to claim 1, wherein the control device opens the switching unit when the oxygen concentration of the space measured by the concentration measuring unit is below a threshold.

3. The nitrogen concentration control device according to claim 1, wherein the oxygen supply unit is located in a space separate from the space.

4. The nitrogen concentration control device according to claim 1, wherein the compressed gas storage unit has an amount of oxygen that can maintain the oxygen concentration in the space above a threshold when the nitrogen from the nitrogen storage unit is released into the space.

5. The aforementioned concentration measuring unit is driven by an independent power supply, The control device is powered by an independent power supply, The nitrogen concentration control device according to claim 1, wherein the switching unit is driven by an independent power supply.

6. A nitrogen concentration management method for managing the nitrogen concentration in a controlled space where a nitrogen storage unit is located, in which nitrogen is stored at a pressure higher than atmospheric pressure, The oxygen supply unit comprises a compressed gas storage section filled with oxygen-containing gas at a pressure higher than that of the space, a piping section which is a path for supplying oxygen from the compressed gas storage section to the space, and a switching section located in the piping section for switching whether or not oxygen is supplied to the space. A concentration measurement step for measuring the oxygen concentration or nitrogen concentration in the aforementioned space, A nitrogen concentration management method comprising the step of controlling the switching unit to supply oxygen from the compressed gas storage unit to the space when the measured oxygen concentration in the space is below a threshold.

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