JP4803657B2 - Entrance / exit detection sensor and entrance / exit detection method - Google Patents

Description

  The present invention relates to an entrance / exit detection sensor and an entrance / exit detection method for detecting entry into or exit from a management space.

Conventional entrance / exit detection sensors include a vibration detection type that detects vibrations of windows and doors, a contact type that detects the opening and closing of windows by a magnet switch provided between the window and the window frame, and a detected object. There are known a heat ray detection type that detects a heat ray from an ultrasonic wave, and an ultrasonic type that transmits an ultrasonic wave to a detection object and receives the reflected wave (see, for example, Patent Document 1).
JP-A-4-106495

  However, among the conventional entrance / exit detection sensors described above, those of the vibration detection type and the contact type cannot detect entry or exit from a window or door in which the entrance / exit detection sensor is installed. In the heat ray detection method and the ultrasonic method, the detection range is limited to the direction in which the heat ray detection sensor and the ultrasonic sensor face. For this reason, in order to reliably detect entry into and exit from the management space, a plurality of entrance / exit detection sensors have to be installed at various locations in the management space, and there is a problem that it takes time and cost.

  The present invention has been made in view of the above circumstances, and includes an entry / exit detection sensor and an entry / exit detection method capable of reliably detecting entry into or exit from a management space while suppressing labor and cost associated with installation. For the purpose of provision.

An entry / exit detection sensor according to the invention of claim 1 made to achieve the above object is an entry / exit detection sensor that can be installed in a management target room managed with all the entrances closed, A space communication member having an air passage that constantly communicates between a management space inside the room and an isolation space partitioned from the management space and through which air flows according to a pressure difference between the management space and the isolation space; , Fluid detection means for outputting a detection signal corresponding to the flow of air passing through the air passage, and detection of entry or exit from the management space from the entrance / exit according to the output result of the fluid detection means The entrance / exit detection sensor is characterized in that a buffer container is provided which is attached to one end of the space communication member and has an isolation space on the inner side and which is closed except for the communication portion with the air passage .

  According to a second aspect of the present invention, in the entrance / exit detection sensor according to the first aspect, the fluid detection means is a pair of ultrasonic sensors opposed in the axial direction of the air passage with at least a portion of the air passage interposed therebetween. It has the characteristic in that.

  According to a third aspect of the present invention, in the entrance / exit detection sensor according to the second aspect, one of the ultrasonic sensors is held at an opposing position spaced apart from an open port facing the management space in the air passage. A feature is that a sensor holding part is provided to allow air in the management space to flow between the opening and one of the ultrasonic sensors.

  According to a fourth aspect of the present invention, in the entrance / exit detection sensor according to the third aspect, the space communication member has a tube structure in which the inside is an air passage, and the sensor holding portion passes air from one end of the space communication member. It is characterized in that it is composed of a plurality of sensor holding arms each holding one ultrasonic sensor at the tip extending along the axial direction of the path.

  According to a fifth aspect of the present invention, in the entrance / exit detection sensor according to the first aspect, the fluid detection means is a movable member that is operated by a fluid resistance of the air passing through the air passage, and the operation of the movable member is converted into an electric signal. And an output circuit for outputting.

The entry / exit detection method according to the invention of claim 6 is an entry / exit detection method for detecting entry into or exit from a managed room managed with all the entrances closed, wherein Entering or exiting the managed room from the entrance / exit by the air flow that passes through the air passage that always communicates between the management space inside the room and the isolation space partitioned from the management space. The entry / exit detection method to be detected is characterized in that a buffer container that is closed except for a portion communicating with the air passage is provided, and the internal space of the buffer container is used as an isolation space .

[Inventions of Claims 1, 5 and 6 ]
According to the inventions according to claims 1 and 6 configured as described above, when the entrance / exit is opened and the management space inside the room to be managed communicates with the outside of the room to be managed, the pressure in the management space changes and is managed. A pressure difference is generated between the space and the isolation space. Air enters and exits between the management space and the isolation space through the air passage until the pressure in the management space and the isolation space reaches an equilibrium state. At this time, the fluid detection means outputs a detection signal corresponding to the flow of air passing through the air passage, and detects entry from the entrance to the management space or exit from the management space according to the output result.

  Thus, according to the present invention, since the entry or exit is detected by the detection signal caused by the pressure difference between the management space and the isolation space, the entry or exit from the plurality of entrances / exits of the room to be managed is one entry / exit. It can be detected by a detection sensor. Thereby, compared with the case where several entrance / exit detection sensors are installed in each place of management space like before, the effort and cost concerning installation can be held down. In addition, since the entrance / exit detection sensor of the present invention can detect entry or exit even if it is installed at a position away from a window or door as long as it is in a management space, the entrance / exit detection sensor of the conventional vibration detection type or contact type Compared with, the degree of freedom of installation location is improved. Here, the fluid detection means may be configured to convert the operation of the movable member operated by the fluid resistance into an electric signal by an output circuit and output the electric signal (Invention of Claim 5).

[Invention of claim 2]
According to the second aspect of the present invention, a change in the air flow velocity in the air passage can be detected as a change in propagation time when an ultrasonic wave is transmitted and received between a pair of ultrasonic sensors. In addition, a change in the temperature of the management space can be detected as a change in the velocity of sound calculated from the propagation time of the ultrasonic wave or the propagation time.

[Invention of claim 3]
According to a third aspect of the present invention, when the air in the management space can flow between the open port facing the management space in the air passage and one of the ultrasonic sensors, the change in the temperature of the management space is ultrasonically detected. Can be reliably detected as a change in propagation time or sound speed.

[Invention of claim 4]
According to the fourth aspect, variation in the distance between the opening of the air passage and the one ultrasonic sensor can be suppressed.

  Hereinafter, a first embodiment of the present invention will be described with reference to FIGS. FIG. 1 shows a room 100 to be managed according to the present invention. The management target room 100 is a room in a building (for example, a building, a detached house, a warehouse, etc.). The management target room 100 is surrounded by walls, and a plurality of entrances 105 through which people can enter and exit are provided, for example. A window 102 or a door 103 is fitted in each of the entrances and exits 105, and the management space 101 inside the management target room 100 is isolated from the outside (for example, outdoors) by closing the window 102 and the door 103. It has become. In this management space 101, the entrance / exit detection sensor 10 of the present invention is installed.

  As shown in FIG. 2, the entrance / exit detection sensor 10 is fixed to the inner wall surface of the room 100 to be managed by, for example, a dedicated holder 30. The entrance / exit detection sensor 10 has a cylindrical structure with both ends open and allows air to pass therethrough, and is held at both ends of the cylindrical body 11 so that the axial direction of the cylindrical body 11 (FIG. 2). And a pair of ultrasonic sensors 20, 20 arranged opposite to each other in the vertical direction).

  As shown in FIG. 3, the ultrasonic sensor 20 has a flat cylindrical structure as a whole. The rear end portion of the ultrasonic sensor 20 projects sideways to form a flange 22. On the other hand, the front end portion of the ultrasonic sensor 20 has a truncated cone shape whose diameter is reduced toward the front end surface, and the front end surface is an ultrasonic wave transmitting / receiving surface 21.

  The cylindrical body 11 includes a measurement tube portion 12 having a measurement flow path 12a on the inner side, a sensor housing portion 13 that is integrally formed with the lower end portion of the measurement tube portion 12, and one ultrasonic sensor 20 is housed and held on the inner side. Consists of The inner diameter of the measurement flow path 12a is, for example, 4 [mm], and the inner diameter of the sensor housing portion 13 is larger than the inner diameter of the measurement flow path 12a. Further, as shown in FIG. 2, both opening edges of the measurement tube portion 12 are chamfered so as to be rounded.

  A plurality of sensor holding arms 14 and 14 extend from the end of the cylindrical body 11 that is open to the management space 101 side. For example, four sensor holding arms 14 are provided in the circumferential direction of the cylindrical body 11 at intervals of 90 degrees. 2 and 3 show only two sensor holding arms 14 and 14 that face each other in the radial direction of the cylindrical body 11.

  Specifically, the sensor holding arm 14 moves the outer portion of the wall body standing up from the peripheral surface of the cylindrical body 11 (measurement pipe part 12) to the management space 101 in the measurement pipe part 12 (measurement flow path 12a). The cylindrical body 11 has a structure extending in the axial direction (upward in FIG. 2) so as to be away from the facing opening 12b, and a locking groove 14a is formed at each end. The flanges 22 of the ultrasonic sensor 20 are locked in the locking grooves 14a, and the four sensor holding arms 14 cooperate to hold one ultrasonic sensor 20. Accordingly, the ultrasonic sensor 20 is held at a facing position that is separated from the open port 12b of the measurement tube unit 12 by a predetermined distance.

  On the other hand, a plurality of sensor holding pieces 15 are formed on the inner peripheral surface of the sensor housing portion 13. For example, four sensor holding pieces 15 are provided in the circumferential direction of the sensor housing portion 13 at intervals of 90 degrees (in FIG. 2 and FIG. 3, two sensor holding pieces 15 opposed in the radial direction are provided. , 15 only). A locking groove 15 a is formed at the tip of the sensor holding piece 15. The flanges 22 of the ultrasonic sensor 20 are locked in these locking grooves 15a, and the four sensor holding pieces 15 cooperate to hold one ultrasonic sensor 20. Accordingly, the ultrasonic sensor 20 is held at a facing position slightly separated from the opening 12c on the side opposite to the opening 12b facing the management space 101 in the measurement tube unit 12. Hereinafter, when distinguishing between the ultrasonic sensors 20, 20, the one held by the sensor holding arm 14 (the management space 101 side) is appropriately referred to as “ultrasonic sensor 20 A” and held by the sensor holding piece 15. This is referred to as “ultrasonic sensor 20B”.

  Here, the distance between the pair of ultrasonic sensors 20, 20 is, for example, 0.1 [m]. In addition, the ultrasonic sensor 20A is arranged farther from the measurement tube unit 12 than the ultrasonic sensor 20B, and the air in the management space 101 can flow between the ultrasonic sensor 20A and the measurement tube unit 12. ing.

  The ultrasonic sensors 20, 20 are held by the sensor holding arm 14 and the sensor holding piece 15 that are integrally formed with the cylindrical body 11, so that the distance between the ultrasonic sensors 20, 20 and each ultrasonic sensor 20 are set. , 20 and the opening 12b, 12c of the measurement tube portion 12 can be prevented from being dispersed, and performance variation between products can be restrained.

  A connecting pipe 31 is connected to the sensor housing portion 13 of the cylindrical body 11. The connecting pipe 31 has a funnel structure, and a stepped portion 32 is formed over the entire periphery of the upper opening edge. The stepped portion 32 is fitted with the outer peripheral surface of the sensor accommodating portion 13 and is abutted against the end surface. In the present embodiment, the tubular body 11 and the connecting pipe 31 constitute the “space communication member” of the present invention. The internal space of the cylindrical body 11 and the connecting pipe 31 that are in communication with each other corresponds to the “air passage” of the present invention.

A buffer container 33 is connected to the lower end of the connecting pipe 31. The buffer container 33 has a hollow box structure, and the inner container space 34 (corresponding to the “isolation space” of the present invention) inside the buffer container 33 is isolated from the management space 101 by the wall portion constituting the buffer container 33. ing. Further, an attachment hole 33a is formed through the upper wall portion of the buffer container 33, and the lower end portion of the connecting pipe 31 is inserted and fixed therein. Thereby, the management space 101 and the container internal space 34 are connected via the internal space of the cylindrical body 11 and the connecting pipe 31. Here, the buffer container 33 is formed of a material (for example, plastic or metal) that is not deformed by a change in atmospheric pressure, and the volume of the container inner space 34 is, for example, 1 [L] (10 ⁻³ [m ³ ]. ]).

  By the way, the ultrasonic sensors 20 and 20 are connected to the control unit 40 by electric wires 35 as shown in FIG. The ultrasonic sensors 20 and 20 are controlled by a transmission / reception switching signal from a control unit 41 provided in the control unit 40. When one of the ultrasonic sensors becomes a transmitter, the other becomes a receiver, and at a predetermined timing, The receiver is switched. Then, the detection signals of the ultrasonic sensors 20 and 20 as wave receivers are taken into the clock counter 42 through an amplifier circuit (not shown).

  The clock counter 42 includes a time until the ultrasonic wave transmitted from one ultrasonic sensor 20A is received by the other ultrasonic sensor 20B (hereinafter referred to as “forward propagation time S1” as appropriate), and the other ultrasonic sensor. The time until the ultrasonic wave transmitted from 20B is received by one ultrasonic sensor 20A (hereinafter referred to as “reverse propagation time S2” as appropriate) is counted. The frequency of the clock counter 42 of this embodiment is 1 GHz, for example. That is, the detection accuracy of the clock counter 42 is 1 [nanosecond].

  The forward propagation time S1 and backward propagation time S2 of the ultrasonic waves measured by the clock counter 42 are stored in the memory 43 and transmitted to the arithmetic processing unit 44 one by one. The arithmetic processing unit 44 calculates the flow velocity V of the air that has passed through the cylindrical body 11, the speed of sound C of the ultrasonic waves, and the temperature T based on the propagation times S 1 and S 2 in both the forward and reverse directions. Here, when the distance between the ultrasonic sensors 20 and 20 is L, the flow velocity V, the sound velocity C, and the temperature T are obtained by the following arithmetic expressions.

  V = (L / 2) · (1 / S1-1 / S2) (1)

  C = (L / 2) · (1 / S1 + 1 / S2) (2)

  T = (C−331.5) /0.6 (3)

  The flow velocity V, the sound velocity C, and the temperature T calculated by the above equation are also stored in the memory 43 one by one. Further, the arithmetic processing unit 44 compares each data newly stored in the memory 43 (propagation time S1, S2, flow velocity V, sound speed C, temperature T) with each data stored before that. The presence / absence of entering / exiting the management space 101 is determined and a signal is output.

  The control unit 40 includes a communication processing unit 45 with a built-in communication modem (for example, “T-NCU”). A signal from the arithmetic processing unit 44 is transmitted through the communication processing unit 45, for example, security. It is transmitted to the monitoring center of the company and transmitted to the alarm device 46 (for example, buzzer, lamp). The control unit 40 may be installed in the management space 101 or may be installed outside the management target room 100.

The structure of the entrance / exit detection sensor 10 of the present invention is as described above, and the operation will be described below.
For example, the entrance / exit detection sensor 10 is activated in a state in which all windows 102 and doors 103 of the management target room 100 are closed and all persons leave the management space 101. Then, after elapse of a predetermined waiting time when the management space 101 and the in-container space 34 of the buffer container 33 are in an equilibrium state, transmission of ultrasonic waves is started, and propagation times S1 and S2 in both forward and reverse directions are measured. The measured propagation times S1 and S2 are stored in the memory 43 one by one, and the flow velocity V, sound velocity C, and temperature T are calculated from the propagation times S1 and S2 and the above relational expressions (1) to (3). These are also stored in the memory 43. Then, the arithmetic processing unit 44 compares each data newly stored in the memory 43 with each data stored in the past, and a reference range in which a change amount per unit time (for example, 1 second) is set in advance. It is determined whether it is within.

  Here, when all the windows 102 and the doors 103 are held in the closed state (the state shown in FIG. 1), the atmospheric pressure in the management space 101 and the atmospheric pressure in the container space 34 are also kept in an equilibrium state. No rapid air flow occurs inside the measurement flow path 12a. Further, the temperature of the management space 101 does not change abruptly. Therefore, the amount of change per unit time of the propagation times S1 and S2 between the ultrasonic sensors 20 and 20 is substantially “0”.

  As shown in FIG. 5, any window 102 or door 103 of the management target room 100 is illegally opened from the outside, and the management space 101 and the outside of the management target room 100 (for example, Communication with the outside), the pressure in the management space 101 changes due to the influence of outside air, and a pressure difference occurs between the management space 101 and the in-container space 34 of the buffer container 33.

  Then, air enters and exits between the management space 101 and the container space 34 until the atmospheric pressures in the management space 101 and the container space 34 are brought into an equilibrium state again, and the air flows into the measurement flow path 12a. Occurs. Thereby, the calculation values of the ultrasonic propagation times S1 and S2 and the flow velocity V between the ultrasonic sensors 20 and 20 change. In addition, when the temperature of the management space 101 changes due to the influence of outside air, and the air flows between the ultrasonic sensor 20A and the measurement pipe unit 12, the calculated values of the sound velocity C and the temperature T also change.

  If it is determined that the amount of change per unit time of each data (propagation time S1, S2, flow velocity V, sound velocity C, and temperature T) exceeds a preset reference range, fraud to the management space 101 A signal is output from the arithmetic processing unit 44 that there is a safe entry / exit, the alarm device 46 issues an alarm, and an abnormality is reported to the monitoring center.

More specifically, it is as follows. If a sudden pressure change of 10 [Pa] occurs in 0.1 seconds due to opening of the window 102 or door 103 and opening of the entrance / exit 105, the management space 101 and the container inner space 34 are in 0.1 seconds. 10 ⁻⁷ [m ³ ] of air enters and exits between the two. At this time, the flow velocity of the air passing through the measurement flow path 12a having an inner diameter of 4 [mm] is about 7.95 × 10 ⁻² [m / sec]. Further, since the distance between the ultrasonic sensors 20 and 20 is 0.1 [m], if the sound velocity is 340 [m / sec], the amount of change in the propagation time based on the state before the entrance 105 is opened is as follows. As the formula
(7.95 × 10 ⁻² /340)×(0.1/340)≈7.0×10 ⁻⁸ [seconds]
That is, about 70 [nanoseconds]. Further, since the sound velocity changes by 0.06 [m / sec] per 0.1 degrees C, when the temperature of the management space 101 changes by 0.1 degrees C by opening the entrance 105, the entrance 105 is opened. The amount of change in propagation time based on the state before
(0.06 / 340) × (0.1 / 340) ≈5.0 × 10 ⁻⁸ [seconds]
That is, about 50 [nanoseconds].

  The atmospheric pressure changes about 1000 Pa in normal times and about 5000 Pa in typhoons, but these are changes in units of several hours, and change 10 [Pa] in 0.1 seconds as described above. Therefore, it is unlikely that a change in atmospheric pressure is erroneously detected as a change in atmospheric pressure due to the opening of the entrance / exit 105. Depending on the season and the climate, the temperature difference between the management space 101 and the outside is about 20 degrees at the maximum, so that the temperature in the management space 101 does not change suddenly when all the entrances 105 are closed. Therefore, there is a low possibility that a temperature change in the closed management space 101 is erroneously detected as a temperature change due to the opening of the entrance 105.

  Thus, according to this embodiment, based on the change in the propagation time, the flow velocity, the sound velocity, or the temperature caused by the pressure difference between the management space 101 and the container internal space 34, the entry into the management space 101 or the management space 101 Therefore, one entry / exit detection sensor 10 can detect entry or exit from a plurality of entrances 105. Therefore, compared to the conventional case where a plurality of entrance / exit detection sensors are installed at various locations in the management space, it is possible to reduce the labor and cost related to the installation. In addition, since the entrance / exit detection sensor 10 of this embodiment can detect entry into or exit from the management space 101 even if it is installed at a position distant from the window 102 or the door 103, the entrance / exit of the conventional vibration detection system or contact system is used. The degree of freedom of the installation location is improved as compared to the exit detection sensor. In addition, since a space is provided between the ultrasonic sensor 20A and the opening 12b of the measurement flow path 12a so that the air in the management space 101 flows therethrough, the temperature change in the management space 101 and the accompanying sound velocity The change can be detected more reliably.

[Other Embodiments]
The present invention is not limited to the above-described embodiment. For example, the embodiments described below are also included in the technical scope of the present invention, and various other than the following can be made without departing from the scope of the invention. It can be changed and implemented.

( 1 ) In the above embodiment, ultrasonic waves are transmitted and received in both directions between the ultrasonic sensors 20 and 20, but may be transmitted and received only in one direction. For example, at the same time as the ultrasonic wave transmitted from the ultrasonic sensor 20A (20B) on the transmission side is received by the ultrasonic sensor 20B (20A) on the reception side, the ultrasonic wave is again transmitted from the ultrasonic sensor 20A (20B) on the transmission side. May be repeated, and the number of times the ultrasonic sensor 20A (20B) on the transmission side transmits ultrasonic waves per unit time may be monitored to detect the change. Further, the ultrasonic propagation time S1 (S2) may be measured each time to monitor the change.

( 2 ) In the above embodiment, a change in flow velocity and a change in temperature are detected using a pair of ultrasonic sensors 20, 20, but a pair of ultrasonic sensors are used to detect a change in flow velocity. Another pair of ultrasonic sensors may be used to detect the change. Here, as a configuration for detecting a change in flow velocity, the configuration described in the above embodiment (a measurement channel 12a is provided between a pair of ultrasonic sensors 20 and 20, and one end of the measurement channel 12a is managed. The space 101 may be opened and the other end communicated with the in-container space 34). In addition, as a configuration for detecting a temperature change, for example, one ultrasonic sensor 20, 20 is installed on each wall portion of the management target room 100 facing each other, and ultrasonic waves are transmitted across the management space 101. What is necessary is just to make it transmit / receive.

( 3 ) The entrance / exit detection sensor may have the following structure instead of the ultrasonic sensors 20 and 20. That is, a windmill (corresponding to the “movable member” of the present invention) that can be rotated by receiving wind pressure is provided in the flow path of the cylindrical body 11 that communicates the management space 101 with the internal space 34 or the internal space 112. The rotation of the windmill may be detected by a rotation detection circuit (corresponding to the “output circuit” of the present invention) and output to the control unit 40 as an electric signal.

( 4 ) The ultrasonic propagation times S1 and S2 may be measured by a time measuring means other than the clock counter 42.

( 5 ) The entrance / exit detection sensor 10 may be installed on the ceiling surface of the management target room 100, for example.

( 6 ) The entrance / exit detection sensor 10 may be installed vertically so that the ultrasonic sensors 20, 20 face each other in the vertical direction, or may be installed so as to be obliquely intersected with the vertical direction. Alternatively, it may be installed horizontally so as to face each other in the horizontal direction.

( 7 ) The entrance / exit detection sensor 10 can be used not only for a crime prevention purpose to detect an unauthorized entry / exit into the management space 101 but also for confirming the safety of a person in the management space 101.

( 8 ) In the above embodiment, the connecting pipe 31 and the buffer container 33 are separate parts, but they may be integrally formed.

( 9 ) The entrance / exit detection sensor 10 may be installed not only in the management space 101 provided in the building but also in the interior space of an automobile to detect entry into the interior of the vehicle.

Plan sectional drawing of the room for management concerning one embodiment of the present invention Side cross-sectional view of entrance / exit detection sensor Side sectional view of cylindrical body and connecting pipe Block diagram of control unit Plan view of the room under management with the doorway open

Explanation of symbols

10 Entrance / exit detection sensor 11 Cylindrical body (space communication member)
12b Open port 14 Sensor holding arm 20 Ultrasonic sensor 31 Connecting pipe (space communication member)
33 Buffer container 34 Space inside container (isolation space )
100 Management target room 101 Management space 105 Entrance / exit

Claims (6)

An entrance / exit detection sensor that can be installed in a managed room managed with all the entrances closed .
There is an air passage that constantly communicates between a management space inside the room to be managed and an isolation space partitioned from the management space, and through which air flows according to a pressure difference between the management space and the isolation space. A space communication member,
Fluid detection means for outputting a detection signal corresponding to the flow of air passing through the air passage;
In accordance with the output result of said fluid detecting means, the entry and exit sensor you detect the departure of the entry or the management space from the entrance opening to the management space,
An entrance / exit detection sensor characterized in that a buffer container is provided which is attached to one end of the space communication member and has the isolation space inside, and is closed except for a communication portion with the air passage.   The entrance / exit detection sensor according to claim 1, wherein the fluid detection means is a pair of ultrasonic sensors facing each other in the axial direction of the air passage with at least a part of the air passage interposed therebetween. .   A sensor holding part is provided to hold one of the ultrasonic sensors at a position facing the open port facing the management space in the air passage, and the open port and the one ultrasonic sensor The entrance / exit detection sensor according to claim 2, wherein air in the management space can flow between The space communication member has a tube structure whose inside is the air passage,
The sensor holding part is composed of a plurality of sensor holding arms that hold the one ultrasonic sensor at a tip that extends from one end of the space communication member along the axial direction of the air passage. The entrance / exit detection sensor of Claim 3. The fluid detection means includes a movable member that operates by a fluid resistance of air passing through the air passage,
The entrance / exit detection sensor according to claim 1, comprising an output circuit that converts an operation of the movable member into an electrical signal and outputs the electrical signal. An entrance / exit detection method for detecting entry into or exit from a managed room managed with all entrances closed,
The entrance to the management target room from the entrance / exit or the management by the flow of air passing through the air passage always connected between the management space inside the management target room and the isolation space partitioned from the management space In the entrance / exit detection method for detecting exit from the target room,
A method for detecting entry / exit, comprising: providing a buffer container that is closed except for a portion that communicates with the air passage, and using the internal space of the buffer container as the isolation space.

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