Concentration measurement device

Patent metadata

Field	Value
Publication number	US-2017102325-A1
Application number	US-201615384351-A
Country	US
Kind code	A1
Filing date	Dec 20, 2016
Priority date	Jul 3, 2014
Publication date	Apr 13, 2017
Grant date	—

Abstract

A gas concentration measurement device measures a gas concentration based on an absorbance of sample gas in a region between a light source that emits infrared light and a detector that detects the infrared light. The gas concentration measurement device includes a rotating member, first and second band pass filters on the rotating member, and a rotational driver. The first and second band pass filters are located on a pair of planes that intersect each other. The rotational driver rotates the rotating member around the rotating shaft to switch between a first state, in which the infrared light from the light source is transmitted through the first band pass filter, and a second state, in which the infrared light from the light source is transmitted through the second band pass filter.

First claim

What is claimed is:

1 . A gas concentration measurement device that measures a gas concentration based on an absorbance of sample gas in a region between a light source that emits infrared light and a detector that detects the infrared light, the gas concentration measurement device comprising:
a rotating member that is rotatable around a predetermined rotating shaft; a first band pass filter and a second band pass filter provided on the rotating member; and a rotational driver that rotates the rotating member around the rotating shaft; wherein the first band pass filter and the second band pass filter are located on first and second planes that intersect each other; and the rotational driver rotates the rotating member around the rotating shaft to switch between a first state, in which the infrared light from the light source is transmitted through the first band pass filter, and a second state, in which the infrared light from the light source is transmitted through the second band pass filter.

2 . A gas concentration measurement device that measures a gas concentration based on an absorbance of sample gas in a region between a light source that emits infrared light and a detector that detects the infrared light, the gas concentration measurement device comprising:
a rotating member that is rotatable around a predetermined rotating shaft; a first band pass filter and a second band pass filter provided on the rotating member; and a rotational driver that rotates the rotating member around the rotating shaft; wherein the rotating shaft intersects an optical axis direction of the infrared light that travels from the light source toward the detector; and the rotational driver rotates the rotating member around the rotating shaft to switch between a first state, in which the infrared light from the light source is transmitted through the first band pass filter, and a second state, in which the infrared light from the light source is transmitted through the second band pass filter.

3 . The gas concentration measurement device according to claim 1 , wherein
the first band pass filter is a band pass filter that transmits the infrared light in an absorption band of the sample gas; and the second band pass filter is a band pass filter that blocks the infrared light in the absorption band of the sample gas and transmits the infrared light with a wavelength different from a wavelength of the infrared light transmitted by the first band pass filter.

4 . The gas concentration measurement device according to claim 1 , wherein the first and second planes are perpendicular or substantially perpendicular to each other.

5 . The gas concentration measurement device according to claim 1 , further comprising n band pass filters, n being an integer of 2 or more, that are provided on the rotating member and that include the first band pass filter and the second band pass filter; wherein
the n band pass filters are located on n planes that intersect each other; the n planes include the first and second planes; and a crossing angle between adjacent planes of the n planes is θ degrees and Expression (1) is satisfied:
[{( n− 1)×180}/ n]− 5≦θ[{( n− 1)×180}/ n]+ 5  Expression (1).

6 . The gas concentration measurement device according to 1 , wherein the rotational driver includes a stepper motor.

7 . The gas concentration measurement device according to claim 1 , further comprising:
a housing that contains the rotational driver and a sample cell; wherein the rotating member is disposed in the sample cell.

8 . The gas concentration measurement device according to claim 1 , wherein the rotating member includes a main portion that is L-shaped or substantially L-shaped.

9 . The gas concentration measurement device according to claim 1 , wherein the rotating member includes holes in which the first band pass filter and the second band pass filter are fitted.

10 . The gas concentration measurement device according to claim 2 , wherein the rotating member includes holes in which the first band pass filter and the second band pass filter are fitted.

11 . The gas concentration measurement device according to claim 1 , wherein the rotational driver includes a motor that is not a stepper motor.

12 . The gas concentration measurement device according to claim 8 , wherein the rotating member includes:
a side wall portion that is connected to a surface of the main portion; and a rotating shaft receiving portion that is connected to the side wall portion and includes a receiving hole.

13 . The gas concentration measurement device according to claim 7 , wherein the sample cell is an integral portion of the housing.

14 . The gas concentration measurement device according to claim 7 , wherein the sample cell and the housing are separate and distinct structures.

15 . The gas concentration measurement device according to claim 1 , wherein the rotating shaft extends perpendicular or substantially perpendicular to an optical axis direction of the infrared light that travels from the light source toward the detector.

16 . The gas concentration measurement device according to claim 7 , wherein the rotational driver is disposed outside of the sample cell and inside of the housing.

17 . The gas concentration measurement device according to claim 7 , wherein the rotating shaft extends through a hole provided in a wall of the sample cell.

18 . The gas concentration measurement device according to claim 5 , wherein
the rotating member includes a main portion that is one-half polygon shaped; and an interior angle of the one-half polygon shaped main portion is equal or substantially equal to the crossing angle between the adjacent planes of the n planes.

19 . The gas concentration measurement device according to claim 2 , wherein the first band pass filter and the second band pass filter are located on first and second planes that intersect each other.

20 . The gas concentration measurement device according to claim 2 , further comprising:
a housing;
wherein the housing contains the rotational driver and a sample cell; and
the rotating member is disposed in the sample cell.

Assignees

• Murata Manufacturing Co

Inventors

• Yasuda Masaaki
• Tsubono Masanori
• Ogushi Naoki

Classifications

• G01N21/3504 Primary

  for analysing gases, e.g. multi-gas analysis · CPC title

• G01N21/61

  Non-dispersive gas analysers {(G01N21/3504 takes precedence)} · CPC title

• G01N2201/0686

  Cold filter; IR filter · CPC title

• G01N33/004 Primary

  CO or CO2 · CPC title