Gas concentration measurement device
A gas concentration measurement device that includes: a waterproof housing including a wall that defines an internal space, the wall including an opening communicating between the internal space and an outside of the housing; a measurement instrument in the internal space, the measurement instrument constructed to measure a concentration of a gas; a gas permeable membrane covering the opening, the gas permeable membrane allowing passage of the gas and substantially blocking passage of moisture; and a driving body constructed to vibrate the gas permeable membrane.
1 . A gas concentration measurement device comprising:
a waterproof housing including a wall that defines an internal space, the wall including an opening communicating between the internal space and an outside of the housing;
a measurement instrument in the internal space, the measurement instrument constructed to measure a concentration of a gas;
a gas permeable membrane covering the opening, the gas permeable membrane allowing passage of the gas and substantially blocking passage of moisture; and
a driving body constructed to vibrate the gas permeable membrane.
2 . The gas concentration measurement device according to claim 1 , wherein the driving body is constructed so as to take a plurality of shapes when energized or heated.
3 . The gas concentration measurement device according to claim 2 , wherein the driving body is a piezoelectric body.
4 . The gas concentration measurement device according to claim 2 , wherein the driving body is a bimetal.
5 . The gas concentration measurement device according to claim 1 , wherein the driving body is on a side of the gas permeable membrane facing the internal space.
6 . The gas concentration measurement device according to claim 1 , wherein the driving body is film-shaped.
7 . The gas concentration measurement device according to claim 1 , wherein the driving body is on the gas permeable membrane.
8 . The gas concentration measurement device according to claim 7 , wherein the driving body is constructed as a support for the gas permeable membrane.
9 . The gas concentration measurement device according to claim 1 , wherein the gas permeable membrane and the driving body are on a side of the opening facing the internal space.
10 . The gas concentration measurement device according to claim 1 , further comprising:
a control circuit that controls vibration of the driving body,
wherein the control circuit is constructed to drive the driving body (1) such that the gas permeable membrane does not project toward the outside of the housing beyond a position of the gas permeable membrane in a non-vibrating state, or (2) such that the gas permeable membrane vibrates greater toward the internal space than toward the outside of the housing with respect to the position of the gas permeable membrane in the non-vibrating state.
11 . The gas concentration measurement device according to claim 10 , further comprising:
a first power supply that supplies electricity to the measurement instrument; and
a second power supply that supplies electricity to the control circuit,
wherein the first power supply and the second power supply are in the internal space.
12 . The gas concentration measurement device according to claim 1 , further comprising:
a power supply that supplies electricity to the measurement instrument, the power supply located in the internal space.
13 . The gas concentration measurement device according to claim 1 , further comprising:
an antenna constructed to transmit detection data based on a measurement signal representing the concentration of the gas to an outside of the gas concentration measurement device.
14 . The gas concentration measurement device according to claim 1 , wherein the wall of the housing is a metal or a polymeric material.
15 . The gas concentration measurement device according to claim 1 , wherein the gas permeable membrane comprises a porous polymeric film or an amorphous polymeric film.
16 . The gas concentration measurement device according to claim 1 , wherein the gas permeable membrane has a thickness of 150 μm or less.
17 . The gas concentration measurement device according to claim 1 , wherein the driving body is a circular plate-shaped piezoelectric body.
18 . The gas concentration measurement device according to claim 1 , wherein a shape of the driving body in a plan view is smaller than a shape of the gas permeable membrane in the plan view.
19 . The gas concentration measurement device according to claim 1 , wherein the measurement instrument comprises a carbon dioxide measurement sensor.
20 . The gas concentration measurement device according to claim 1 , wherein the driving body is at least one of a flat strip-shaped body that extends in a diameter direction of the gas permeable membrane, two flat strip-shaped bodies that are orthogonal to each other and each of which extend in the diameter direction of the gas permeable membrane, a plurality of individual driving bodies having a rectangular shape in a plan view and arranged in a circumferential direction of the gas permeable membrane with predetermined intervals therebetween, and a flat annular membrane that extends along an outer periphery of the gas permeable membrane.