Humidity Sensors

Abstract

To reduce adsorption of gas, which is harmful for sensor measurement, to a humidity sensor element.SOLUTION: A humidity sensor comprises: a humidity sensor element 111; a sensor chamber 11 having an opening 112 and housing the humidity sensor element 111; a volume adjustment chamber 12 having an opening 112 and communicating with the sensor chamber 11; a filter 1131 that can reduce the permeation of gas larger than water particles, and covers the opening 112 of the sensor chamber 11; and a volume adjustment unit 122 that covers the opening 112 of the volume adjustment chamber 12, and makes the internal pressure of the sensor chamber 11 match the external pressure via the volume adjustment chamber 12.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a humidity sensor in which a humidity sensor element is housed in a sensor chamber. [Background technology]

[0002] Conventionally, there has been known a humidity sensor in which a filter is provided at the opening of a sensor chamber in which a humidity sensor element is provided in order to prevent physical flying objects such as dust or dirt from adhering to the humidity sensor element (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 63-132152 Summary of the Invention [Problem to be solved by the invention]

[0004] However, conventional humidity sensors such as that disclosed in Patent Document 1 cannot prevent the intrusion of gases that are harmful to sensor measurement, and improvements are required.

[0005] The present invention has been made to solve the above-mentioned problems, and has an object to provide a humidity sensor capable of reducing adsorption of gases harmful to sensor measurement to a humidity sensor element. [Means for solving the problem]

[0006] The humidity sensor according to the present invention includes a humidity sensor element, a sensor chamber having an opening and housing the humidity sensor element, a volume adjustment chamber having an opening and communicating with the sensor chamber, a filter capable of reducing the permeation of gases larger than water molecules and covering the opening of the sensor chamber, It is possible to block gas, The sensor chamber is characterized by comprising a volume adjustment section which covers an opening of the volume adjustment chamber and adjusts the internal pressure of the sensor chamber to match the external pressure via the volume adjustment chamber. Effect of the Invention

[0007] According to the present invention, since it is configured as described above, it is possible to reduce the adsorption of gases that are harmful to the sensor measurement to the humidity sensor element. [Brief description of the drawings]

[0008] [Figure 1] 1 is a diagram showing a configuration example of a humidity sensor according to a first embodiment; [Diagram 2] 5A and 5B are diagrams illustrating an example of the operation of the humidity sensor according to the first embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. Embodiment 1 FIG. 1 is a diagram showing an example of the configuration of a humidity sensor according to the first embodiment. 1, the humidity sensor has a sensor chamber 11 and a volume adjustment chamber 12 provided in a housing 1. The sensor chamber 11 and the volume adjustment chamber 12 communicate with each other via a passage 13.

[0010] Sensor chamber 11 is a space that houses humidity sensor element 111. Humidity sensor element 111 is capable of measuring the humidity inside sensor chamber 11. Sensor chamber 11 is also provided with an opening 112 on one surface (the upper surface in FIG. 1).

[0011] Opening 112 of sensor chamber 11 is covered by laminated filter 113. The outer periphery of laminated filter 113 shown in FIG. 1 is attached to the upper surface of sensor chamber 11. Laminated filter 113 shown in FIG. 1 is composed of filter 1131 and filter (second filter) 1132.

[0012] The filter 1131 is water molecule The filter 1131 is capable of reducing the permeation of larger gases. For example, a graphene oxide film is used as the filter 1131. water molecule is allowed to penetrate into the sensor chamber 11, water molecule Larger gases are restricted from permeating into the sensor chamber 11 .

[0013] Filter 1132 is a filter capable of blocking physical flying objects such as dust or dirt. Filter 1132 covers filter 1131 and is exposed to the atmosphere. Filter 1132 may be any filter capable of blocking physical flying objects such as dust or dirt. Examples of filter 1132 include a filter made of sintered metal or porous ceramics.

[0014] Note that opening 112 of sensor chamber 11 may be configured in a mesh-like shape. This makes it possible to support filters 1131 and 1132 at opening 112 even when filters 1131 and 1132 are thin (cannot stand on their own), and thus improves strength.

[0015] 1 shows a case where filter 1132 is laminated on filter 1131. However, filter 1132 is not an essential component of the humidity sensor, and filter 1132 does not necessarily have to be provided in the humidity sensor.

[0016] The volume adjusting chamber 12 is a space that communicates with the sensor chamber 11 via a passage 13. Furthermore, the volume adjusting chamber 12 has an opening 121 provided on one surface (the upper surface in FIG. 1).

[0017] Opening 121 of volume adjustment chamber 12 is covered by volume adjustment part 122. The outer periphery of volume adjustment part 122 shown in FIG. 1 is attached to the upper surface of volume adjustment chamber 12. Volume adjustment part 122 can block gas, and also has a function of adjusting the internal pressure of sensor chamber 11 to match (including the meaning of approximately match) the external pressure via volume adjustment chamber 12. Note that, for example, assuming that the temperature change in sensor chamber 11 is about 0 to 80 degrees, the internal pressure fluctuation in sensor chamber 11 is about 90 kPa to 120 kPa, and volume adjustment part 122 is configured to be able to absorb this internal pressure fluctuation.

[0018] Examples of the volume adjustment part 122 include a metal diaphragm or a metal bellows. When a metal bellows is used as the volume adjustment part 122, there is an advantage that the operating range of the volume adjustment part 122 is large (the degree of freedom in designing the internal volume is increased). When a metal diaphragm is used as the volume adjustment part 122, there is an advantage that the volume adjustment part 122 is easy to manufacture. On the other hand, when a metal diaphragm is used as the volume adjustment part 122, the operating range of the volume adjustment part 122 is smaller than that of a metal bellows (the amount of fluctuation of the internal gas needs to be suppressed within the operating range of the diaphragm). FIG. 1 shows a case where the volume adjustment part 122 is made of a metal diaphragm.

[0019] Next, the effects of the humidity sensor according to the first embodiment shown in FIG. 1 will be described. Here, in order to reduce the adsorption of gases that are harmful to the sensor measurement to the humidity sensor element 111, water molecule It is possible to install a filter that does not allow larger gases to pass into the sensor chamber 11. However, water molecule If sensor chamber 11 is configured not to allow larger gases to pass therethrough, the internal pressure of sensor chamber 11 will fluctuate due to temperature changes and the like, and these internal pressure fluctuations can be a factor in causing sensor measurement errors.

[0020] Therefore, in the humidity sensor according to the first embodiment, in order to equalize the internal pressure and the external pressure of the sensor chamber 11, the volume adjustment section 122 that does not allow gas to pass through is provided in the volume adjustment chamber 12. As a result, in the humidity sensor according to the first embodiment, even if the internal pressure of the sensor chamber 11 fluctuates due to temperature changes or the like, the volume adjustment section 122 adjusts the internal pressure of the sensor chamber 11 to match the external pressure. For example, as shown in FIG. 2, when the internal pressure of the sensor chamber 11 rises above a reference value, the volume adjustment section 122 (metal diaphragm) deforms in an expanding direction (see reference numeral 201 shown in FIG. 2), and when the internal pressure of the sensor chamber 11 falls below the reference value, the volume adjustment section 122 (metal diaphragm) deforms in a contracting direction (see reference numeral 202 shown in FIG. 2). As a result, in the humidity sensor according to the first embodiment, it is possible to suppress sensor measurement errors due to temperature changes or the like.

[0021] In addition, the sensor chamber 11 has an opening 112, water molecule A filter 1131 is provided that can reduce the transmission of larger gases. water molecule While securing the entrance and exit to the sensor room 11, water molecule This makes it possible to suppress the inflow of larger gases into sensor chamber 11. For filter 1131, it is particularly effective to use a graphene oxide film. Moreover, by stacking filter 1132 capable of blocking physical flying objects such as dust or dirt on filter 1131, it becomes possible to prevent the physical flying objects from entering sensor chamber 11.

[0022] As described above, according to the first embodiment, the humidity sensor includes a humidity sensor element 111, a sensor chamber 11 having an opening 112 and housing the humidity sensor element 111, a volume adjustment chamber 12 having an opening 112 and communicating with the sensor chamber 11, water molecule The humidity sensor according to the first embodiment is provided with a filter 1131 that can reduce the permeation of larger gases and covers the opening 112 of the sensor chamber 11, and a volume adjustment part 122 that covers the opening 112 of the volume adjustment chamber 12 and makes the internal pressure of the sensor chamber 11 equal to the external pressure via the volume adjustment chamber 12. This makes it possible for the humidity sensor according to the first embodiment to reduce adsorption of gases that are harmful to sensor measurement to the humidity sensor element 111.

[0023] It should be noted that, within the scope of the present invention, any of the components of the embodiments may be modified or omitted. [Explanation of symbols]

[0024] 1 Case 11 Sensor Room 12 Volume adjustment chamber 13 Passage 111 Humidity sensor element 112 Opening 113 Laminated Filter 121 Opening 122 Volume adjustment section 1131 Filter 1132 Filter (Second Filter)

Claims

1. A humidity sensor element; a sensor chamber having an opening and housing the humidity sensor element; a volume adjustment chamber having an opening and communicating with the sensor chamber; a filter that can reduce the permeation of gases larger than water molecules and that covers an opening of the sensor chamber; a volume adjustment section that is capable of blocking gas, covers an opening of the volume adjustment chamber, and makes the internal pressure of the sensor chamber equal to the external pressure via the volume adjustment chamber; A humidity sensor equipped with

2. A second filter capable of blocking physical flying objects and laminated on the filter is provided.

2. The humidity sensor according to claim 1.

3. The filter is made of a graphene oxide film.

3. The humidity sensor according to claim 1 or 2.

4. The volume adjustment portion is made of a metal diaphragm.

4. The humidity sensor according to claim 1, wherein the humidity sensor is a sensor that detects humidity of the object.

5. The volume adjustment part is made of a metal bellows.

4. The humidity sensor according to claim 1, wherein the humidity sensor is a sensor that detects humidity of the object.

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