JPH0662357U - Gas concentration measuring device - Google Patents

Abstract

(57) [Summary] [Purpose] The object of the present invention is to pressurize the gas to be measured so that the pressure of the gas becomes high even with a small amount of gas. [Structure] A cylinder is provided at a place communicating with the gas cell. When the piston of the cylinder is driven after the gas is sealed in the gas cell, the pressure in the gas cell is increased.
Since the amount of gas required for measurement is approximately the total volume of the inner volume of the gas cell and the inner volume of the cylinder, it is possible to measure the gas concentration with the gas pressurized even with a small amount of gas.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a gas concentration measuring device.

[0002]

[Prior art]

 For example, in order to investigate the deterioration of insulating oil in an oil-filled transformer, a certain amount of the insulating oil is taken out to an extractor, this is bubbled to extract dissolved gas, and then the concentration of the gas is measured. Has been. In order to measure the gas concentration, the dissolved gas from the extractor is introduced into the gas cell, infrared rays are transmitted through the gas cell, and the amount of transmitted infrared rays is detected by an infrared sensor.

In measuring such a gas concentration, in order to improve the measurement accuracy, the pressure of the gas is made higher than the atmospheric pressure. Conventionally, in order to increase the gas pressure, the discharge pressure (sealing pressure) of the air pump used to introduce the dissolved gas from the extractor into the gas cell is used. According to this, the gas pressure increases according to the amount of dissolved gas introduced by the air pump.

However, in order to increase the gas pressure by such means, it is necessary that the absolute amount of the gas to be measured is large, and if the amount is small, that is, it is necessary to increase the pressure in the gas cell. If the amount is insufficient, the pressure inside the gas cell cannot be increased sufficiently, resulting in insufficient measurement of the gas concentration.

[0005]

[Problems to be solved by the device]

 An object of the present invention is to make it possible to sufficiently increase the pressure in the gas cell even when the amount of gas to be measured is small.

[0006]

[Means for Solving the Problems]

 The present invention is characterized in that a cylinder is provided at a place communicating with the gas cell, and the gas introduced and enclosed in the gas cell is pressurized by the cylinder.

[0007]

[Action]

 When the cylinder is operated after the gas is enclosed in the gas cell, the pressure inside the gas cell is increased. The amount of gas required for measurement is now about the total volume of the internal volume of the gas cell and the content volume of the cylinder, and the amount of gas required for measurement is higher than that of the conventional pressurization method using an air pump. The amount will be small.

[0008]

【Example】

 An embodiment of the present invention will be described with reference to the drawings. A gas cell 1 is provided with an infrared radiation source 2 at one end and an infrared sensor 3 at the other end. The gas to be measured introduced into the gas cell 1 is irradiated with infrared rays from the infrared source 2, and the infrared rays transmitted through the gas are measured by the infrared sensor 3. 4 is a wind filter, 5 is a bandpass filter, and 6 is a chopper.

Reference numeral 7 is an introduction pipe for introducing the gas from the gas extractor into the gas cell 1, 8 is an exhaust pipe for returning the gas in the gas cell 1 to the gas extractor, and 9 is for introducing the gas from the extractor into the gas cell 1. It is an air pump used for. These configurations are not particularly different from the conventional device.

According to the present invention, a cylinder 10 is provided for increasing the pressure of the gas introduced and enclosed in the gas cell 1. Specifically, an introduction valve 11 is provided in the introduction pipe 7, a discharge valve 12 is provided in the discharge pipe 8, and a cylinder 10 is provided so as to communicate with any place between the introduction valve 11 and the discharge valve 12. . In the illustrated example, a cylinder 10 is provided so as to communicate with the introduction pipe 7. Reference numeral 13 is a piston of the cylinder 10.

Reference numeral 14 is a drive source for the piston 11, and FIG. 1 shows an example using an air cylinder 15. A compressor 16 communicates with the air cylinder 15 via valves 17 and 18. When the valve 17 is opened, the piston 13 is driven to the right, and when the valve 18 is opened, it is driven to the left, and this drive increases the pressure in the gas cell 1.

Next, the measurement operation will be described with reference to FIGS. First, with the introduction valve 11 and the discharge valve 12 opened, the gas to be measured from the extractor is introduced into the gas cell 1 via the inlet pipe 7 by the air pump 9, so that the entire measurement system is filled with the gas. Replace with. After a certain time has passed after the replacement, the introduction valve 11 and the discharge valve 12 are closed and the air pump 9 is stopped. As a result, the gas is sealed in the gas cell 1 and the cylinder 10. The filling amount at this time is almost equal to the total of the internal volumes of the gas cell 1 and the cylinder 10.

In this state, the valve 18 is opened, high-pressure air from the compressor 16 is sent to the air cylinder 15, and the piston 13 of the cylinder 10 is driven to reduce the internal volume of the cylinder 10. The pressure rises. When the piston 13 moves in the drive stroke range and stops in this way, the gas in the gas cell 1 is in a state of being pressurized at a predetermined pressure.

In this state, the output from the infrared sensor 3 is converted by the A / D converter 20, and the output from this is selected by the selector 21 and sampled for a certain period of time. The memory 22 stores this sampling value. The stored value is sent to the calculator 23, where the average value S1 (calculation output) is calculated.

Next, the introduction valve 11 and the discharge valve 12 are opened, and the air pump 9 is operated to instantly replace the gas in the gas cell 1 with external air. In this state, the selector 21 selects the output from the infrared sensor 3 and samples it for a certain period of time. The sampling value is stored in the memory 24. The stored value is sent to the calculator 25, where the average value S 2 (reference output) is calculated.

Both average values S1 and S2 are sent to the calculator 26, and the ratio (S1 / S2) or the difference (S1-S2) of both average values is calculated, and the concentration of the measurement target gas is calculated from the calculation result. You will be asked.

The drive source 14 for the piston 13 in FIG. 1 is an air cylinder 15, but a compressor 16 is required for that purpose. Therefore, there is an inconvenience that it cannot be used in a place where the compressor 16 is not installed. To solve this, an electromagnetic solenoid 27 may be used as shown in FIG.

Alternatively, a linear motor 28 may be used as shown in FIG. When the linear motor 28 is used, it is convenient because the stroke length of the piston 13 can be made sufficiently longer than when the electromagnetic solenoid 27 is used. In FIG. 4, 29 is a pressure sensor for detecting the pressure in the gas cell 1, which detects that the pressure in the gas cell 1 has reached a specified value, and the drive source 14 of the piston 13 (the linear motor 28 in the example in the figure). ) To stop the operation.

[0019]

[Effect of device]

 As described above, according to the present invention, in increasing the gas pressure in the gas cell when measuring the gas concentration, a smaller amount of gas is required than in the case of using the conventional air pump. For example, even if the amount of gas is small, it is possible to pressurize the gas, and thus it is possible to measure the gas concentration with high accuracy.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an embodiment of the present invention.

FIG. 2 is a block diagram for measuring gas concentration.

FIG. 3 is a cross-sectional view showing another embodiment of the present invention.

FIG. 4 is a sectional view showing still another embodiment of the present invention.

[Explanation of symbols]

 1 Gas Cell 2 Infrared Source 3 Infrared Sensor 7 Introducing Pipe 8 Exhaust Pipe 9 Air Pump 10 Cylinder 13 Piston 14 Drive Source

Claims (1)

[Scope of utility model registration request] 1. An infrared source is provided at one end of the gas cell and an infrared sensor is provided at the other end of the gas cell, and an infrared ray from the infrared source is introduced into the gas under pressure introduced into the gas cell to be measured. In the gas concentration measuring device for measuring the concentration of the gas by measuring the infrared ray that has passed through the gas with the infrared sensor, a cylinder is provided at a location communicating with the inside of the gas cell, and the gas is introduced into the gas cell. And a gas concentration measuring device which pressurizes the enclosed gas by the cylinder.