JPH0664142U - Gas concentration measuring device - Google Patents

Abstract

(57) [Summary] [Purpose] An object of the present invention is to shorten the time required to replace the gas inside the cylinder when the cylinder is used to pressurize the gas to be measured. [Structure] A cylinder is provided at a place communicating with the gas cell. A guide extending to the inside of the cylinder is provided so that the gas circulates inside the cylinder in the process of introducing the gas into the gas cell. The introduced gas circulates so as to reach the inside of the cylinder by the guide. As a result, the gas inside the cylinder is promptly replaced.

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.

In order to solve this, the present inventor has separately proposed a configuration in which a cylinder is provided at a location communicating with the gas cell and the gas introduced and enclosed in the gas cell is pressurized by the cylinder. . This is convenient because the pressure in the gas cell can be sufficiently increased even when the amount of gas to be measured is small.

On the other hand, in this type of measurement, before pressurizing the gas cell, the gas inside the gas cell is replaced by the gas to be measured, and the gas concentration inside the gas cell is made uniform by including a pressurizing system including a cylinder. There is a need. However, since the cylinder is installed in a direction that intersects the gas introduction path, it is difficult for gas to flow into the cylinder, so the time required for gas replacement becomes long. As a result, it takes a long time to measure the gas concentration.

[0007]

[Problems to be solved by the device]

 The present invention aims at shortening the time required for equalizing the gas concentration inside the gas cell including the cylinder even when the cylinder has a pressurizing function.

[0008]

[Means for Solving the Problems]

 The present invention has a guide, which circulates the introduced gas inside the cylinder, inside a cylinder provided to pressurize the gas introduced inside the gas cell, at a place communicating with the inside of the gas cell. It is characterized by being provided.

[0009]

[Action]

 The guide allows the gas to circulate and flow inside the cylinder, which allows the gas to be quickly replaced inside the cylinder. Therefore, the time required to equalize the gas concentration inside the gas cell including the cylinder is shortened sufficiently.

[0010]

【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. The air pump 10 used for this is a cylinder for increasing the pressure of the gas introduced and enclosed in the gas cell 1.

Specifically, the introduction valve 11 is provided in the introduction pipe 7 and the discharge valve 12 is provided in the discharge pipe 8, and a cylinder is provided so as to communicate with any place between the introduction valve 11 and the discharge valve 12. 10 is provided. 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 denotes a drive source for the piston 11, which uses a linear motor 15 in FIG. Instead of the linear motor 15, an air cylinder, an electromagnetic solenoid or the like may be used. These configurations have been separately proposed by the present inventors as described above.

According to the present invention, a guide 16 extending from the introduction pipe 7 toward the inside of the cylinder 10 is provided. However, the guide 16 does not reach the movement range of the piston 13.

In the above configuration, the gas to be measured from the extractor is introduced into the gas cell 1 by the air pump 9 through the introduction pipe 7 with the introduction valve 11 and the discharge valve 12 opened first before the measurement. By introducing the gas, the entire measuring system is replaced with the gas. At the time of this introduction, the guide 16 causes the gas to circulate and flow into the inside of the cylinder 10 as indicated by the arrow in the figure. Therefore, the replacement of the gas reaching the inside of the cylinder 10 can be performed in a short time.

After the gas replacement is completed in this manner, the introduction valve 11 and the discharge valve 12 are closed and the air pump 9 is stopped. As a result, the gas is enclosed in the gas cell 1 and the cylinder 10. The enclosed 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, when the linear motor 15 drives the piston 13 of the cylinder 10 to reduce the internal volume of the cylinder 10, the pressure of the gas in the gas cell 1 rises. In this way, when the piston 13 moves within the drive stroke range and stops, the gas in the gas cell 1 is pressurized at a predetermined pressure. In this state, the gas concentration may be measured by the output from the infrared sensor 3.

FIG. 2 shows an experimental result of the gas replacement rate according to the present invention. When the guide 16 is not provided, it takes 5 minutes or more to replace the gas until the gas concentration becomes uniform. In contrast, when the guide 16 is provided according to the present invention, it can be replaced within 2 minutes as shown by the solid line.

[0019]

[Effect of device]

 As described above, according to the present invention, when the gas concentration is measured, even if a cylinder is used to increase the gas pressure in the gas cell so that a small amount of gas is sufficient, it is necessary to replace the gas before measurement. The effect is that the time required for can be shortened sufficiently.

[Brief description of drawings]

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

FIG. 2 is a characteristic curve diagram showing a gas conversion rate.

[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 16 Guide

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, at a location communicating with the inside of the gas cell, the gas is introduced and sealed in the gas cell. In addition to providing a cylinder for pressurizing the gas,
A gas concentration measuring device provided with a guide for circulating the introduced gas inside the cylinder.