Device with sensor

Abstract

To provide a device which does not become less durable even in a foul environment and can use a sensor with high reliability.SOLUTION: A gas detector includes: a sensor unit 103 having a sensor with a detection element; a shutter mechanism with a shutter for exposing the detection element to the surrounding atmosphere or blocking the detection element from the surrounding atmosphere; and a control unit 105. The control unit 105 controls operations of the shutter and activates the sensor when the sensor is exposed.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to an apparatus provided with a sensor, such as a gas detection apparatus.

Background Art

[0002] As an apparatus provided with a sensor, a gas detection apparatus provided with a gas sensor is known. Among gas detection apparatuses, there is a gas detection apparatus that is installed in an environment with relatively harsh conditions to measure the ambient gas concentration, and in particular, a gas detection apparatus that is used in an environment with a poor ambient atmosphere such as a corrosive gas. In this type of gas detection apparatus, it is impossible to install it separately from the surrounding gas due to the function of measuring the gas concentration and / or gas components. As a result, the life of the gas detection apparatus is shortened due to the influence of the surrounding corrosive gas, etc., and the frequency of component replacement and maintenance increases. In addition, there is a problem that the reliability of the measurement data is lowered or lost due to a failure or malfunction of the gas detection apparatus.

[0003] Therefore, for example, as disclosed in Patent Document 1 (Japanese Patent No. 6465621), a gas inlet, a gas outlet, a gas sensor disposed in a through space that allows the inlet and the outlet to communicate, and a primary shutter unit that opens and closes the inlet by a user's operation, and a handy-type gas detection apparatus having a secondary shutter unit that opens and closes the outlet in conjunction with the primary shutter unit has been proposed. According to this gas detection apparatus, since the inlet and the outlet are respectively blocked by the primary shutter unit and the secondary shutter unit, it is possible to suppress the gas sensor from being exposed to the gas and deteriorating, or the gas sensor from being splashed with liquid and malfunctioning.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in the gas detection device described in Patent Document 1, since the opening and closing of the inlet and outlet are performed by the user manually operating the shutter unit, there are problems as described below.

[0006] First, at least a part of the user's body is exposed to the gas atmosphere to be detected for the operation of the shutter unit, or the entire gas detection device is exposed to the gas atmosphere to be detected. Therefore, when the gas to be detected is a corrosive gas, there is a risk of affecting the body, and there is also concern about the deterioration of the gas detection device, making it unsuitable for gas detection in a harsh environment containing corrosive gas.

[0007] Second, the opening and closing timing and the open time of the inlet and outlet depend on the user's experience value, proficiency in work, etc. Therefore, these uncertain factors may have an adverse effect on the durability improvement effect of the gas detection device.

[0008] Third, when the operation of the shutter unit by the user is insufficient, there is a possibility that the inlet and outlet may not be reliably opened and closed.

[0009] Generally, in a harsh environment containing a corrosive gas environment or a large amount of water vapor, for example, in a device used in industrial wastewater purification equipment or a hot water storage tank, it is necessary to make the device have a highly airtight structure or perform purging of the inside of the device by air purge for the protection of internal electric circuits, mechanical operating parts, components, and wiring, etc. However, in a gas detection device that measures the ambient gas concentration and / or gas components, if it has an airtight structure or performs purging by air purge, it becomes impossible to measure the ambient gas concentration and / or gas components, which is the original purpose, so even though it is used in a harsh environment, these environmental resistance specifications cannot be adopted. Air purge means purging the gas remaining in the target device with compressed external air or the like.

[0010] The above-described problem is not limited to a gas detection device including a gas sensor, but is a common problem for devices including sensors used in harsh environments.

[0011] The present invention has been made in view of the above problems, and an object thereof is to provide a device that can use a sensor with high reliability without impairing durability even in a harsh environment.

Means for Solving the Problem

[0012] According to a first aspect of the present invention, there is provided a sensor unit having a sensor including a detection element, a shutter mechanism including a shutter for exposing or shielding the detection element to or from the surrounding atmosphere, a control unit, and having, wherein the control unit controls the operation of the shutter and is configured to operate the sensor when the sensor is exposed.

[0013] According to a second aspect of the present invention, there is provided a sensor unit having a sensor including a detection element, a purge mechanism for purging gas present inside the sensor unit, a control unit, and having, wherein the control unit is configured to control the operation and non-operation of the purge mechanism in synchronization with the operation of the sensor unit.

[0014] According to a third aspect of the present invention, there is provided a sensor unit having a sensor including a detection element, a shutter mechanism including a shutter for exposing or shielding the detection element to or from the surrounding atmosphere, a control unit, and having, wherein the control unit controls the operation of the shutter and is configured to operate the sensor when the sensor is exposed.

Effect of the Invention

[0015] According to the present invention, an apparatus is provided that can use a sensor with high reliability without impairing durability even in a harsh environment.

Brief Description of the Drawings

[0016]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Embodiments for Carrying Out the Invention

[0017] Hereinafter, an embodiment of the present invention will be described by taking a gas detection device as an example with reference to FIGS. 1 to 4.

[0018] The gas detection device of this embodiment generally includes a mechanism unit 110, a control unit 105, and a communication device 104. The mechanism unit 110 includes a gas sensor unit 103 having a gas sensor 4 with a detection element, a shutter mechanism (shutter 10, shutter position detection mechanism 101, and shutter drive mechanism 102) for exposing or shielding the detection element to / from the surrounding atmosphere, the gas sensor unit 103, and an air valve device 106. Among these, the configurations excluding the blower device 107 are installed inside the housing 100. Note that in FIGS. 1 to 4, an energy supply source such as a battery for operating the gas detection device is not shown.

[0019] The gas sensor unit 103 has a gas sensor 4. The gas sensor 4 has a case and a detection element disposed on the surface of the case, and measures the concentration of the gas to be detected in contact with the detection element. The gas sensor 4 is not particularly limited and can be appropriately selected from various detection methods such as an electrochemical method, a semiconductor method, and an NDIR (Nondispersive Infrared) method according to the type of the gas to be detected. The shutter 10 is opened and closed with respect to the detection element so that the detection element is shielded while the gas sensor 4 is not operating. The shutter drive mechanism 102 is a mechanism for opening and closing the shutter 4, and the shutter position detection mechanism 101 is a mechanism for detecting whether the shutter 10 is in an open state or a closed state.

[0020] The communication device 104 is an interface for transmitting and receiving data to and from other external devices other than this gas detection device. Examples of external devices include servers, cloud servers, personal computers, tablet terminals, smartphones, image display devices, printing devices, and the like. When the external device has a storage device, the measurement data obtained by the gas detection device can be stored in the storage device. When the external device is an image display device, the measurement data obtained by the gas detection device can be displayed on the image display device. When the external device is a printing device, the measurement data obtained by the gas detection device can be printed. The connection method between the gas detection device and the external device is not particularly limited and may be a wireless connection or a wired connection via a cable. Examples of wireless connections include communication methods compliant with the Wi-Fi (Wireless Fidelity) standard, communication methods using Bluetooth (registered trademark), communication methods using LTE (Long Term Evolution), and communication methods using LTE-M.

[0021] The housing 100 has a scavenging port 108 and has a structure in which the inside is sealed except for the scavenging port 108 and the location where the blower device 107 is connected when the gas detection device is not performing ambient gas measurement. The blower device 107 is a device for purging the inside of the housing 100 by introducing outside air into the inside of the housing 100. As the blower device 107, for example, an air compressor or a scavenging fan can be used. Inside the housing 100, an air valve device 106 is connected to the blower device 107.

[0022] When the blower 107 is operated with the air valve device 106 and the shutter 10 open, the pressure inside the housing 100 becomes higher than the outside air, and the gas present inside the gas sensor unit 103 is discharged to the outside of the housing 100 through the scavenging port 108, that is, purged. The position of the scavenging port 108 is not particularly limited, but it is preferably installed near the gas sensor. As a result, after the measurement of the gas concentration is completed, the gas around the gas sensor 4 is scavenged quickly and reliably, and as a result, the deterioration and malfunction of the gas sensor 4 are suppressed.

[0023] The control unit 105 controls the operations of the shutter position detection mechanism 101, the shutter drive mechanism 102, the gas sensor unit 103, the communication device 104, and the air valve device 106, and can be composed of a microcomputer, a microcontroller, a programmable logic controller, an application-specific integrated circuit, and other programmable circuits, etc. In this specification, the "control unit" may physically be one configuration, or two or more control units may functionally cooperate to form one "control unit".

[0024] Next, it is arranged inside the housing 100. A specific form of the structure of the mechanism part 110 including the shutter position detection mechanism 101, the shutter drive mechanism 102, the gas sensor unit 103, and the air valve device 106 will be described with particular reference to FIGS. 2, 3, and 4.

[0025] The mechanism part 110 is installed, for example, on the bottom surface inside the housing 100 to measure the concentration of the gas existing on the lower side inside the housing 100. However, the position and orientation of the mechanism part 110 inside the housing 100 are not particularly limited and can be appropriately changed according to the properties of the gas to be measured.

[0026] The mechanism unit 110 includes a base 15, a rotating disk A rotatably attached on the base 15, a geared motor 1 for rotating the rotating disk A, a sensor holder 6 fixed to the base 15 with the rotating disk A in between, and four gas sensors 4 held by the sensor holder 6. The gas sensors 4 and the sensor holder 6 constitute the aforementioned sensor unit. The geared motor 1 and its drive circuit (not shown) correspond to the shutter drive mechanism 102 shown in FIG. 1. The sensor holder 6 holds the gas sensors 4 with the detection elements of the gas sensors 4 exposed. The gas sensors 4 are arranged concentrically with respect to the rotation axis of the rotating disk A and at equal intervals in the circumferential direction, that is, at 90-degree intervals, and are mounted on a sensor substrate 2 provided with a sensor circuit.

[0027] The rotating disk A has a disk-shaped portion and a ring-shaped portion provided on its upper surface. Teeth 12 meshing with the geared motor 1 are formed on the outer peripheral surface of the disk-shaped portion, and the rotating disk A can be rotated by driving the geared motor 1. The sensor holder 6 holds the gas sensors 4 with their detection elements facing the rotating disk A, and is fixed to the base 15 and arranged inside the ring-shaped portion of the rotating disk A.

[0028] Gas sensor opening holes are respectively formed at positions of the disk-shaped portion of the rotating disk A facing each gas sensor 4. Similarly, measurement windows 14 are respectively formed at positions of the base 15 facing each gas sensor 4. Thereby, when the gas sensors 4, the gas sensor opening holes, and the measurement windows 14 are aligned in a straight line, the detection elements of the gas sensors 4 are exposed to the surrounding gas, but when the rotating disk A rotates and the gas sensor opening holes are displaced from the positions facing the gas sensors 4, the detection elements of the gas sensors 4 are configured to be shielded from the surrounding gas. That is, the inside of the ring-shaped portion of the disk-shaped portion of the rotating disk A functions as a shutter 10. In this embodiment, since the four gas sensors 4 are arranged at equal intervals in the circumferential direction with respect to the rotation axis of the rotating disk A, the opening and closing operation of the shutter 10 is repeated four times each time the rotating disk A makes one rotation.

[0029] In this embodiment, four gas sensors 4 are used. However, the number of gas sensors 4 is not limited to four, and it may be one, two, three, or five or more. Also, the arrangement of the gas sensors 4 is not particularly limited. However, when there are a plurality of gas sensors 4, it is preferable to arrange the gas sensors 4 concentrically with respect to the rotation axis of the turntable A and at equal intervals in the circumferential direction. By arranging a plurality of gas sensors 4 in this way, it becomes possible to reduce the load on the mechanism unit 101 such as the geared motor 1.

[0030] When using a plurality of gas sensors 4, each gas sensor 4 may measure the concentration of a different type of gas, or at least two or all of the plurality of gas sensors 4 may measure the concentration of the same type of gas. When there are two or more gas sensors 4 that measure the concentration of the same type of gas, for example, by averaging the results measured by those gas sensors 4, the concentration of the gas can be measured with higher accuracy.

[0031] On the lower surface of the sensor holder 6, a first seal member 7 is installed corresponding to each gas sensor 4 for better blocking the detection element of the gas sensor 4 from the surrounding gas when the shutter 10 is closed. Since the gas sensor 4 has a lifespan and needs to be replaced regularly, the first seal member 7 achieves both the blocking of the detection element of the gas sensor 4 from the surrounding gas and the improvement of the convenience of replacing the gas sensor 4. Between the turntable A and the base 15, a second seal member 13 is installed to prevent gas from entering the vicinity of the gas sensor 4 from the gap between the shutter 10 provided with the gas sensor opening hole and the base 15 provided with the measurement window 14.

[0032] In this embodiment, O-rings are used as the first sealing member 7 and the second sealing member 13, but any sealing member can be used as long as it can block the intrusion of gas between two structures that can move relative to each other. Also, although the shapes of the gas sensor opening hole formed in the shutter 10 and the measurement window 14 are shown as circular, these are not particularly limited as long as they can shield and expose the detection element of the gas sensor 4, and for example, they may be fan-shaped or the like.

[0033] On the upper surface of the ring-shaped portion of the rotating disk A, a cam 9 for a rotation position detection switch is formed, and a rotation position detection switch 3 is disposed at a position facing this. The cam 9 for a rotation position detection switch is formed with unevenness such that the rotation position detection switch 3 turns on when the sensor opening hole of the shutter 10 and the measurement window 14 of the base 15 overlap. The rotation position detection switch 3 corresponds to the shutter position detection mechanism 101 shown in FIG. 1, and the detection method is not particularly limited as long as it turns on / off according to the unevenness of the cam 9 for a rotation position detection switch, and it may be a contact type switch such as a mechanical switch or a non-contact type switch such as an optical switch. The control unit 105 controls the rotation operation of the geared motor 1 based on the on / off signal of the rotation position detection switch 3.

[0034] On the side surface of the ring-shaped portion of the turntable A, a cam 11 for an air valve is formed, and an air valve 8 with an air valve operation switch is arranged at a position facing this. The air valve 8 corresponds to the air valve device 106 shown in FIG. 1. The cam 11 for the air valve is formed as unevenness such that the air valve operation switch turns off when the sensor release hole of the shutter 10 and the measurement window 14 of the base 15 overlap. The detection method of the air valve operation switch is not particularly limited as long as it turns on / off according to the unevenness of the cam 11 for the air valve, and it may be a contact switch such as a mechanical switch or a non-contact switch such as an optical switch. The type of the air valve 8 is not particularly limited, and it may be mechanical or electromagnetic. When using the electromagnetic air valve 8, the control of the shutter 10 and the air valve 8 can be shared only by the cam 9 for the rotation position detection switch.

[0035] As described above, since the cam 9 for the rotation position detection switch and the cam 11 for the air valve are integrally provided on the turntable A, the opening / closing timing of the shutter 10 and the opening / closing timing of the air valve 8 can be synchronized by rotating the turntable A.

[0036] The gas detection device of this embodiment continuously and automatically measures the concentration of the surrounding gas at a predetermined time interval accompanying the rotation of the turntable A. The measurement time interval can be set to a constant time interval, such as 10-minute intervals, 20-minute intervals, 30-minute intervals, etc., by appropriately setting the rotation speed of the turntable A. Also, the measurement time interval does not necessarily have to be constant, and it may be changed between day and night, weekdays and holidays, etc.

[0037] Next, an example of the operation of the gas detection device having the mechanism part 110 shown in FIGS. 2 to 4 will be described with further reference to the flowchart of FIG. 5 and the timing chart of FIG. 6. In the timing chart of FIG. 6, the shapes of the cam 9 for the rotation position detection switch and the cam 11 for the air valve are shown extended linearly for easy understanding of the relationship with the time axis.

[0038] When the gas detection device is activated, the control unit 105 executes various initial settings for the activation operation (S101). The contents of the initial settings include obtaining time information, setting the obtained time, obtaining information on the measurement time interval of the gas concentration, setting the measurement time interval, opening the air valve 8, closing the shutter 10, initial setting of the gas sensor 4, etc. Note that it is assumed that the blower device 107 is operating.

[0039] When the initial settings are completed and the measurement operation starts, the control unit 105 sets a timer in the control unit 105 and starts counting time (S102). Then, it is determined whether the counted time has reached the measurement time interval set in the initial settings (for example, 30 minutes) (S103). If the measurement time measurement interval is reached, the control unit 105 resets the timer (S104) and operates the shutter drive mechanism 102 (S105). During this period, since the air valve 8 is open, the gas around the gas detection device is introduced into the housing 100 by the blower device 107.

[0040] When the shutter drive mechanism 103 is operated, the turntable A rotates and the position detection switch cam 9 operates. The control unit 105 determines whether the position detection switch 3 is on (S106). If it is on, the operation of the shutter drive mechanism is stopped (S107).

[0041] When the position detection switch 3 is on, the shutter 4 is open and the air valve 8 is closed. If the air valve 8 is a solenoid valve, the air valve 8 is closed by the control unit 105 at this time (S108). Since the shutter 4 is open, the gas sensor 4 is exposed to the gas introduced into the housing 100. In this state, the control unit 105 executes measurement of the gas concentration by the gas sensor 4 (S109).

[0042] After measuring the gas concentration, the control unit 105 transmits the data obtained by the measurement to an external device via the communication device 104 (S110). Further, the control unit 105 starts the operation of the shutter drive mechanism 102 (S112). At this point, since the shutter 4 is open, the operation of this shutter drive mechanism 102 can be said to be an operation for closing the shutter 4. After starting the operation of the shutter drive mechanism 102, the control unit 105 determines whether the position detection switch 3 has turned off (S113).

[0043] When the position detection switch 3 turns off, the control unit 105 stops the operation of the shutter drive mechanism 102. In the state where the position detection switch 3 is off, the shutter 4 is closed and the air valve 8 is open. As a result, the gas inside the housing 100 is purged with the gas sensor 4 blocked from the outside air by the shutter 10. In order to more effectively purge the gas around the gas sensor 4, it is preferable to provide a purge hole 5 in the shutter 4 separately from the sensor opening hole. In FIG. 4, four purge holes 5 are arranged between the sensor opening holes in the circumferential direction of the shutter 10 so as to be located near the gas sensor 4, respectively, but the number and arrangement of the purge holes 5 may be arbitrary.

[0044] When the purge operation is completed, the control unit 105 repeats a series of processes starting from the measurement of the measurement time after the initial setting (S103), whereby the measurement of the gas concentration is repeated at predetermined time intervals.

[0045] According to the gas detection device of this embodiment, by providing a shutter opening hole in the disk-shaped portion of the rotating disk A and using this as the shutter 10, it is possible to open and close the shutter 10 by rotating the rotating disk A in only one direction. As a result, it is not necessary to drive the opening and closing of the shutter 10 by the forward and reverse rotations of the geared motor 1, and it can be performed only by forward rotation. Further, it is not necessary to consider the backlash of the gear 12, so the mechanical load on the shutter drive mechanism 102 can be reduced.

[0046] In addition, in order to detect the opening and closing of the shutter 10, usually, a switch for detecting the open state and two switches for detecting the closed state are required. However, according to this embodiment, since the cam 9 for the rotational position detection switch is used, the open state and the closed state of the shutter 10 can be detected with only a single rotational position detection switch 3.

[0047] As described above, while measuring the gas concentration, the gas detection device according to this embodiment performs air purge inside the housing 100 except during the measurement, so that the life and reliability of the gas detection device can be significantly improved. In addition, it becomes possible to install the gas detection device even in an environment where installation has been difficult in the past.

[0048] In addition, in this embodiment, the operation and non-operation of the air valve 8 are controlled in conjunction with the operation of the gas sensor unit 103. Usually, in a device having a purge mechanism, purge is performed by continuously sending in outside air, and this embodiment is significantly different from the prior art in this regard. Thus, by controlling the operation and non-operation of the air valve 8 in conjunction with the operation of the gas sensor unit 103, it is possible to measure the gas concentration with high reliability while reducing the mechanical load on the gas detection device.

[0049] The configuration according to the present invention is applicable not only to gas detection devices but also to other devices used in environments in contact with harmful outside air. For example, by using an ultrasonic distance sensor instead of a gas sensor, it can be applied to a water level measurement device for measuring the water level in a waste liquid tank, for example.

Explanation of Reference Numerals

[0050] 1 Gear motor 2 Sensor substrate 3 Rotational position detection switch 4 Gas sensor 5 Purge hole 6 Sensor holder 7 First sealing member 8 Air valve 9 Cam for rotational position detection switch 10 Shutter 11 Cam for air valve 12 Tooth 13 Second seal member 14 Measurement window 100 Housing 101 Shutter position detection mechanism 102 Shutter drive mechanism 103 Gas sensor unit 104 Communication device 105 Control unit 106 Air valve device 107 Blower device 108 Scavenging port

Claims

1. A sensor unit having a sensor with a detection element, A shutter mechanism having a shutter for exposing or shielding the detection element to / from the surrounding atmosphere, A control unit, And having, The control unit is configured to control the operation of the shutter and operate the sensor when the sensor is exposed, a device.

2. The shutter mechanism has a rotating disk whose rotation is controlled in one direction by the control unit, the device according to claim 1.

3. A plurality of the sensors are arranged concentrically with respect to the rotation axis of the rotating disk, the device according to claim 2.

4. A sensor unit having a sensor with a detection element, A purge mechanism for purging the gas present inside the sensor unit, A control unit, And having, The control unit is configured to control the operation and non-operation of the purge mechanism in conjunction with the operation of the sensor unit, a device.

5. The sensor unit has a purge hole located in the vicinity of the sensor, the device according to claim 4.

6. A sensor unit having a sensor with a detection element, A shutter mechanism having a shutter for exposing or shielding the detection element to / from the surrounding atmosphere, A purge mechanism for purging the gas present inside the sensor unit, A control unit, And having, The control unit is configured to control the operation of the shutter, operate the sensor when the sensor is exposed, and control the operation and non-operation of the purge mechanism in conjunction with the operation of the sensor unit, a device.

7. The shutter mechanism has a rotating disk whose rotation is controlled in one direction by the control unit, the device according to claim 6.

8. A plurality of the sensors are arranged concentrically with respect to the rotation axis of the rotating disk, the device according to claim 6.

9. The sensor unit has a purge hole located in the vicinity of the sensor, the device according to claim 6.

10. The sensor is a gas sensor, the device according to claim 1, 4 or 6.

11. The sensor is an ultrasonic distance sensor, the device according to claim 1, 4 or 6.

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