JPH0631414Y2 - Measuring device for dissolved gas in oil - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to an apparatus for measuring dissolved gas in oil.

(Prior art) To measure the gas dissolved in oil, bubbling gas such as air is introduced into the sample oil taken from electric equipment as bubbles, and the gas dissolved in oil is bubbled. There is a method (gas recovery method) in which the extracted gas is taken in, and the extracted gas is recovered in a gas recovery container to measure the gas.

(Problems to be Solved by the Invention) In the case of using the measuring means as described above, it is necessary to collect and measure a certain volume of the extracted gas, and to completely extract the dissolved gas from the extracted gas of that volume. It is necessary to.

Therefore, the recovery efficiency of the extracted gas becomes an important factor for improving the measurement accuracy, and the finest bubbles (for example, bubbles with a diameter of 10 μm or less) are generated in the oil and dissolved for a long time (for example, 3 to 4 minutes). The gas concentration was measured. Therefore, the measurement time was naturally long.

Further, since fine bubbles are used, a defoaming means for eliminating the bubbles must be installed inside the extractor.

Further, since a fixed volume of recovered gas is required as described above, it is necessary to increase the amount of air with respect to the amount of sample oil by, for example, 5 times or more. For example, if this is set to 5 times, 5 times the indicated value of the measuring device becomes the true value. Therefore, the sensitivity of the measuring instrument cannot be applied as it is, and therefore, the lower limit of the measured concentration must be relatively large. For example, it is currently impossible to measure less than 50ppm.

The purpose of this invention is to measure the amount of gas in the sample oil in a short time and to a low concentration, and to eliminate the need for a defoaming means.

(Means for Solving the Problem) This invention measures the gas dissolved in the recovered gas extracted by bubbling with a gas sensor, and
The recovered gas is circulated by returning the measured gas to the extractor again, and the bubble diameter for bubbling is set to 0.1 to 8.0 mm.

(Operation) Since the recovered gas extracted by bubbling is circulated, the gas-liquid equilibrium state is reached within a short time in the extractor. Since the gas concentration at this time is the dissolved gas concentration, the gas concentration can be detected in a relatively short time.

Further, since the diameter of the bubbles is made relatively large within a range that does not cause a measurement error, the defoaming means is unnecessary and low concentration measurement becomes possible.

(Embodiment) An embodiment of this invention will be described with reference to the drawings. In FIG. 1, reference numeral 1 is an extractor in which a sample oil 2 is put. Further, a bubble generator 3 including a ball filter, a bubble generating tube and the like is installed inside. Extractor 1 at the time of measurement
Bubbling gas such as air is introduced into the bubble generator 3 from the outside through the pump 4.

Bubbles are generated by this air. The gas contained in the sample oil 2 is contained in the bubbles. This extracted gas is sent to the gas recovery container 5, where the gas is detected by the gas sensor 6. The detected value is converted into an electric signal and amplified by the amplifier 7. Then, the detected amount is instructed to the meter 8. As a gas sensor, for example, SnO ₂ , Z
A semiconductor type sensor such as metal oxide such as nO is used.

FIG. 2 shows hydrogen gas in oil measured by a semiconductor type sensor by the apparatus shown in FIG. It is an example of an air concentration equilibrium curve plotted together with.

The peak of this curve has just reached vapor-liquid equilibrium, at which point the measurement is complete. In this example, the peak (340 ppm) is reached 1 minute and 40 seconds after the start of circulation.

FIG. 3 is a gas-liquid equilibrium time characteristic curve in which the time required to reach gas-liquid equilibrium was verified by changing the circulation flow rate and bubble diameter. From this characteristic diagram, the smaller the bubble diameter and the faster the flow velocity, the shorter the time to reach the peak.
Therefore, it can be understood that the measurement time is shortened if the bubble diameter is reduced.

However, when the difference between this peak value and the actual concentration was examined, the results shown in FIG. 4 were obtained. That is, the peak value measured here is the value indicated by the gas sensor 6 in the gas recovery container 5, but from this figure the actual concentration (the concentration of the gas used here is 340 ppm, which was accurately measured beforehand by a gas chromatograph). It is found that a higher bubble diameter indicates a higher value.

From this result, even if the bubble diameter is set to 0.01 mm or less, no matter how the peak value is reached, it cannot be recognized as the true gas concentration. Therefore
It is not preferable to use a bubble diameter of 0.01 mm or less.

If the bubble diameter is less than 0.1 mm, the flow velocity will increase,
The bubbles may reach the gas recovery container 5 without disappearing in the extractor 1. Therefore, oil may touch the gas sensor 6 and damage it. Therefore, it is not preferable to use bubbles having a diameter of less than 0.1 mm.

On the other hand, if the bubble diameter exceeds 8 mm, as will be understood from FIG. 4, the measurement time becomes long, which is unsuitable for this type of measurement.

If the bubble diameter is in the range of 0.1 to 8.0 mm, the bubbles will spontaneously disappear in the extractor 1, and therefore the extractor 1
There is no need to install defoaming means inside. In reality, it is possible to set the ratio of the sample oil amount to the space amount to 1: 1-5. When this is 1: 1, the minimum sensitivity of the gas sensor, for example, 10ppm, can be measured. Therefore, it is possible to measure a low concentration as compared with the conventional configuration.

(Effects of the Invention) As described in detail above, according to the present invention, when measuring the concentration of gas dissolved in oil, it is possible to measure the concentration of gas in a shorter time than before, and to reduce the concentration of defoaming means. There is an effect that can be eliminated.

[Brief description of drawings]

FIG. 1 is an arrangement diagram showing an embodiment of the present invention, FIG. 2 is an air concentration equilibrium curve diagram, FIG. 3 is a gas-liquid equilibrium time characteristic diagram, and FIG. 4 is a concentration difference characteristic diagram. 1 ... extractor, 2 ... sample oil, 3 ... bubble generator, 4 ...
… Pump, 5 …… Gas recovery container, 6 …… Gas sensor,

Claims (1)

[Scope of utility model registration request] 1. An extractor containing a sample oil containing a dissolved gas,
A bubble generator that generates bubbles in the extractor, a gas recovery container that is equipped with a gas sensor that collects the gas bubbled by the bubbling gas sent to the bubble generator, and measures the dissolved gas, and the gas. An apparatus for measuring dissolved gas in oil, comprising: a pump for sending the recovered gas in the collector to the extractor to circulate it, wherein the bubble diameter is 0.1 to 8.0 mm.