JPS5828212Y2 - gas analyzer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an analyzer for analyzing gas components present in a liquid, and particularly relates to an analyzer for analyzing combustible gases present in insulating oil.

Analysis of combustible decomposed gases present in oil is often performed for abnormality diagnosis and maintenance management of oil-filled electrical equipment such as transformers.

A commonly used gas-in-oil analysis device is composed of a combination of a gas extraction device and an extracted gas analysis device.Most gas analysis devices are gas chromatographs, but a variety of extraction devices are used.

The Torricelli vacuum method and the mercury diffusion pump/Tepra pump combination method are the most commonly used, but they are complicated to operate and have safety issues because they use mercury.

The vacuum pump/piston method does not use mercury, but is complicated to operate.

Furthermore, since all of the above methods operate under vacuum,
It is necessary to improve the airtightness of the apparatus, and furthermore, since the extracted gas is under reduced pressure, the gas analysis operation is complicated.

In addition, membrane extraction methods that utilize gas diffusion from polymer membranes are
There are disadvantages such as the time required for extraction, lack of diversity in various gases, and changes in extraction efficiency due to membrane deterioration.

On the other hand, the gas replacement method by blowing carrier gas is a simple method with simple equipment and operation.

FIG. 1 shows a schematic diagram of an analyzer combined with a gas chromatograph.

First, the carrier gas 2 whose flow rate is controlled by the flow rate control valve 21 passes through the oil 3 of the gas extraction container 10 while bubbling, and the extracted gas is guided to the separation column 25 of the gas chromatograph. It is separated and quantified by the detector 30.

Note that FIG. 1 is a flow path diagram when a thermal conductivity type detector is used, and the carrier gas that has passed through the flow path resistor 26 flows to the symmetrical cell side of the detector 30.

Although this extraction method is very simple, there are problems.

In other words, in gas measurement using a gas chromatograph,
The sample in the carrier gas is narrow and has a high concentration (
However, since it is advantageous to have a uniform concentration distribution, rapid gas replacement is required.

However, instantaneous gas extraction is difficult by replacing the dissolved gas with only one flow, and requires a large amount of carrier gas and time.

Therefore, it is disadvantageous unless the sample is limited to a small amount and has a high concentration.

Furthermore, the structure of the gas extraction device greatly affects analysis accuracy.

The present invention has been made in view of the above points, and the seventh object is to provide a dissolved gas analyzer that is a simple device and is equipped with an extraction device that can perform sufficient gas extraction with simple operations.

The feature of this proposal is that two gas extraction devices containing a certain amount of oil are used.
A gas circulation pump such as a diaphragm pump is connected to this, and the pump circulates the gas to bubble it in the oil and extract the gas.
The purpose is to send the extracted gas to a gas chromatograph for separation and detection.

According to the present invention, sufficient gas extraction can be performed, and the extracted gas can be limited to a constant amount with a uniform concentration.

Furthermore, since the extracted gas is at normal pressure, gas analysis becomes easy.

The gas extraction force method and analyzer based on the present invention will be explained below.

Example 1 In order to compare gas replacement by the conventional flow method and gas replacement by the circulation method according to the present invention, measurements were performed using the apparatus shown in FIG.

This device consists of a gas extraction container 1, a diaphragm pump 4, a four-way valve 12, and a detector 32. The four-way valve 12 performs an extraction operation by circulation in the flow path indicated by the solid line, and detects the extracted gas in the flow path indicated by the dotted line. It is guided into a device and measured.

As the detector 32, a constant potential electrolytic gas sensor that selectively detects CO was used.

First, 3 m of insulating oil with 100 ppm of CO dissolved in it.
After injecting t into the extracted solution amount 1 and bubbling it for 5 minutes, the flow path was changed and the extracted gas was measured.

As a result, a signal proportional to the CO concentration as shown in FIG. 3a was obtained.

Next, 3 ml of CO-free insulating oil and the same amount of CO as above were injected, and measurements were performed in a repeating manner.

As a result, as shown in Figure 3, a signal almost the same as that of oil was obtained, and the COO degassing rate was 95% or more.

,Next, we attempted to measure only by conventional distribution.

Leave the four-way valve 12 in the measurement flow path indicated by the dotted line, and set the CO to 1100p.
3 ml each of p-containing insulating oil and air were measured separately.

Figure 4a shows the measurement results for oil, and Figure 5 shows the measurement results for gas.

In the conventional method, the sample gas spreads into the carrier gas while being replaced, and in this experiment, the spread was about 6 times that of the proposed method.

As a result, the height sensitivity of the conventional method is reduced, and the effectiveness of the present invention is clear.

In addition, in the conventional method, when calibrating with standard gas, the peak state is different from that of oil, making calibration difficult.

According to this proposal, since both oil and gas samples can be measured as a fixed amount of gas sample, the peak shapes are the same as shown in Figure 1, making calibration easy and improving analytical accuracy. Can be done.

Embodiment 2 FIG. 5 is a typical configuration diagram of a dissolved gas analyzer based on the present invention, in which a gas extraction section is located within a sampling channel of a gas chromatograph.

This is also a case where a thermal conductivity type detector is used as the detector.

Now, the flow rate of the carrier gas 2 is controlled by the flow rate adjustment valve 21, and the carrier gas 2 passes through the solid line of the four-way valve 11 and 12 to the separation column 25.
, guided to the detector 30 and ready for analysis.

Further, the same carrier gas flows at the same flow rate on the reference cell side of the detector.

Next, regarding the gas extraction operation, the extraction device consists of an extraction container 1, a gas circulation pump 4, and a piping system connecting them, and the extraction container 1 is divided into two chambers by a porous plate 5.

First, the inside of the entire apparatus is replaced with carrier gas.

In this case, the carrier gas whose flow rate is controlled by the flow rate adjustment valve 20 is passed through the three-way valve 14 as the flow path shown by the dotted line, and the force is passed through the pump 4 and the four-way valve 12 to the extraction container 1, and the other is extracted via the four-way valve 11. Transfer to container 1.

Then, the sample introduction section 6 opens the sample discharge section 1 to the atmosphere, and
Replace the equipment and flow path with gas.

This gas replacement operation is not necessary when air intrusion into the gas chromatography is not a problem.

After replacing the gas, the part opened to the atmosphere is closed, the three-way valve 14 is placed in the solid line state, and the pump 4 is operated.

Gas flows through the extraction vessel from the bottom to the top.

Next, when a fixed amount of oil is injected from the sample introduction part 6, the oil 3 is held in the upper part of the porous plate 5, and is bubbled by the circulating gas to extract gas components in the oil.

After a certain period of time, the pump 4 is stopped and the four-way valves 11 and 12 are switched to the dotted line flow path, and the gas in the extrusion container 1 is led to a separation column of a gas chromatograph and is separated and quantified.

The oil in the extraction container 1 can be taken out from the sample discharge part 7 when gas is not flowing.

Here, during the extraction operation, the oil may be splashed to the top in the same way, so it is better to place a carrier on the porous plate 15, or to place a demister or a packed column for liquid replenishment between the pump and the pump.

Since the water droplet extraction operation can be carried out over an arbitrary period of time, extraction is more reliable than with the conventional carrier gas flow method, and the operation is much simpler than with the vacuum force method.

Although a typical example of the structure of the extraction device has been given, various bubbling type degassing devices can be applied.

Regarding the extraction gas separation method, it may not be possible to separate and quantify the gas with a single separation column depending on the gas components.

In this case, analysis becomes possible by preparing as many separation columns as necessary and providing a branch pipe between the four-way valve 12 and the separation column.

Embodiment 3 FIG. 6 is a block diagram of another embodiment based on the present invention.

This is done by providing a sampling container 28, 29 separately from the extraction container in the gas extraction path, and three-way valves 15, 16, 17.
18 and three-way valves 33, 34, the extracted gas in the sampling container is guided to separate separation columns 25, 27, and detected and quantified by detectors 30, 31.

The extraction operation and analysis operation are the same as in Example 1.

As mentioned above, several embodiments of the dissolved gas analyzer based on this proposal have been shown, but compared to the conventional carrier gas method, gas replacement is more reliable, spreading in the sample can be prevented, and a larger amount can be detected. Sensitivity is improved because the sample can be processed.

In addition, the device and operation are much simpler than the conventional vacuum force type.

Furthermore, automation is easy by controlling the operation of the valves and pumps with a timer.

Although the above explanation has mainly been made regarding the gas analysis method in insulating oil, the present invention can also be applied to various solutions.

[Brief explanation of the drawing]

Figure 1 is a flow path diagram of a dissolved gas analyzer using the conventional carrier gas method, Figures 2.5.6 are schematic diagrams of a dissolved gas analyzer based on this proposal, and Figure 3 is a flow diagram of a dissolved gas analyzer based on this proposal. FIG. 4 shows the measurement results obtained by the conventional method. 1... Gas extraction container, 2... Carrier gas, 3... Oil, 4... Gas circulation pump, 5... Porous Plate, 6...Sample injection port, 7...Sample discharge port, 11.12...
・Four-way valve, 14-18...Three-way valve, 20-22
...Flow rate adjustment valve, 25...Separation column, 26...Flow path resistance column, 2γ...
Separation column, 30-32...Gas detector, 33
, 34... Open/close valve.

Claims (1)

[Scope of utility model registration request] In an apparatus for storing a liquid in a sealed container, extracting a gaseous substance present in the liquid, and analyzing the extracted gas with a gas chromatograph, an inlet for introducing a carrier gas into the container; A gas analysis device comprising a gas extraction device provided with two gas flow ports and connected to the gas circulation pump for circulating the carrier gas in the liquid.