JPS6179137A - Measuring method of water concentration in oil - Google Patents

Abstract

PURPOSE:To prevent a heating body from breaking by heating nearby oil by the heating body up to the boiling point of water and forming air bubbles of vapor while the pressure in a measurement cell is held negative. CONSTITUTION:The oil to be detected which is put in a sample container 18 is placed in a uniform state by a stirring machine 19 and sucked up by a pump 10 through a suction conduit 9 to fill the measurement cell 7, a float switch 20 detects the liquid level when it enters its detection range, and a solenoid valve 13 is closed when the liquid level rises up to a specific position. Then, the pump 10 is held in operation continuously while the valve 13 is closed and solenoid valves 21 and 15 are opened, and a pressure reduction stage is entered. Further, a switch 22 detects the pressure between the valves 13 and 21, and when specific negative pressure is obtained, the valve 21 is closed and the pump 10 is stopped. Then, the heating body 2 is turned on and water concentration is measured, and then when the measuring operation is finished, the valve 15 is operated to link a coupling conduit 11 with an atmosphere open conduit 23 and the valves 13 and 21 are opened to discharge the detected oil from the cell 7 and switch 20 into the container 18.

Description

Detailed Description of the Invention Field 1 The present invention involves immersing a heating element in the oil to be tested in a measurement cell, and heating the oil near the heating element with the heating element to a temperature higher than the boiling point of water. The present invention relates to a method of measuring 11 degrees of moisture in oil by generating water vapor bubbles on a surface that comes into contact with the body and detecting the water vapor bubbles with a sensor.

Previously, the Karl Fischer method has been used to measure the water concentration in oil, but this method requires special reagents, requires time and science for titration, and cannot be measured continuously. There were other problems. Therefore, in recent years, by taking advantage of the fact that water in oil evaporates due to heating and forms bubbles in the oil, measurements have been made to measure changes in the state quantities of oil liquid, such as the amount of bubbles generated or changes in temperature due to bubble generation. Accordingly, a method for easily measuring 11 degrees of moisture in oil has been proposed (Japanese Patent Application No. 57-105437 and Japanese Patent Application No. 111-1982).
No. 997).

Among these, the former method of Japanese Patent Application No. 57-105437 is as follows:
As shown in FIG. 2, the heating element 2 is immersed in oil in the oil tank 1, and by heating the oil near the heating element to a temperature higher than the boiling point of water, the contact surface between the oil and the heating element 2 is heated. Water vapor bubbles A are generated, and the sound produced by the bubbles A, changes in the amount of light transmitted by the bubbles, changes in the dielectric constant of the oil, etc. are observed with a sensor 3 immersed in the oil, and the measurement device groove 4 measures the data. This method converts the water concentration into water concentration and outputs it.
As shown in FIG. 3, the method of No. 7-111997 involves forming a protrusion 6 or a recess in a heating body 2 containing a filament 5, and immersing this heating body 2 in oil at a predetermined inclination angle θ. , an iA setting in which the heating element 2 is heated to a temperature higher than the boiling point of water, and the amount by which water vapor bubbles generated from the projections 6 or recesses change the temperature of the oil liquid due to the heat of vaporization is measured by the change in the resistance value of the filament 5. It is. These methods have made it possible to easily and continuously measure the water-containing layer or water concentration of oil, but these methods and devices require sensors and heating elements to be installed inside the oil tank, so they are not subject to external forces. When the oil tank shakes due to pressure or pressure, the oil level fluctuates, and the sensor detects the same signal as when air bubbles are generated, making it impossible to accurately measure the water concentration in the oil. In particular, in quenching baths that store quenching oil for quenching metals, the quenching bath often shakes when metals are put in and taken out, and the quenching oil is often stirred to improve cooling efficiency. However, since the oil level fluctuates due to vibration, accurate measurements were almost impossible.

On the other hand, a heating element is immersed in the oil to be tested and heats the oil in the vicinity to a temperature higher than the boiling point of water, and a sensor is immersed in the oil to be tested to measure water vapor bubbles generated from the heating element. In a device equipped with a measurement mechanism that converts the signal from this sensor into water concentration and outputs it, it is possible to obtain accurate measured values without being affected by fluctuations in the oil level. Moreover, in order to enable continuous measurement, a measurement cell is provided outside the oil tank for the oil to be tested, the heating element and sensor are installed inside this measurement cell, and the oil to be tested is fed from the oil tank to the measurement cell. A device was proposed that was equipped with a suction mechanism that filled and sealed the inside of the container.

That is, FIG. 4 shows an example of a device in which a measurement cell is provided outside the oil tank described above.
A measurement self is provided separately. This measuring self is placed above the oil tank 1, and inside it is equipped with a heating element 2 that heats the oil above the boiling point of water, and a sensor 3 that measures water vapor bubbles generated by heating the heating element 2. is installed. The heating body 2 is formed by installing a filament 2b in a holder 2a made of a material such as glass or metal, and is heated by the filament 2b to about 110°C, for example, and heats oil in the vicinity to a temperature higher than the boiling point of water. , the water contained in the oil is evaporated into water vapor and air bubbles are generated in the oil, and the sensor 3 is provided opposite to the heating element 2 to measure the air bubbles of water vapor. It is. This measurement may be performed by detecting the sound of bubbles, by detecting changes in the amount of light transmitted or scattered by the bubbles, or by detecting changes in the dielectric constant of the oil due to the generation of bubbles. Depending on the measuring method, the measuring element can be selected as appropriate, for example, a sound receiving element is used for measuring the generated sound, and a photoelectric element is used for optical measurement.

The signal thus detected by the sensor 3 is sent into the measuring mechanism 4, converted into water concentration, and displayed on an appropriate output means such as a printout or digital display.

In the above device, 8 is a suction mechanism. This suction machine #1
8 is a suction pipe 9 whose lower end extends into the oil 11 and whose upper end is connected to the measuring self, and a pump 1 provided above the measuring self.
0, a connecting pipe 11 disposed between the pump 10 and the measuring self, a return pipe 12 disposed from the pump 10 into the oil tank 1, and a second pipe disposed midway through the suction pipe 9. A solenoid valve 13 consisting of a one-way solenoid valve, a level sensor 14 provided on the measurement self side in the middle of the connecting pipe 11, an electromagnetic valve 15 consisting of a three-way Rm valve provided on the pump 10 side, a bypass line 16 for equalizing the pressure inside the measuring self with the oil tank internal pressure when returning the oil to the oil tank;
Pump 10. It has a control section 17 that controls electromagnetic valves 13 and 15 and a level sensor 14, and when the pump 10 is operated, the oil in the oil tank 1 is sucked into the measuring cell and filled and sealed.

In the above device, a measurement cell is provided outside the oil tank, and since the measurement cell is filled and sealed with the oil to be tested, it is possible to accurately measure the water concentration even if an external force is applied.

However, in the above-mentioned apparatus, the temperature of the surface of the heating element is above the boiling point of water, that is, above 100°C. In this case, the heating element must be heated against the cooling effect of the oil, and a large amount of energy is required to heat the heating element to a predetermined temperature. Therefore, for example, when an electric heating element including a filament or the like is used as the heating element, there is a problem in that an overvoltage is applied to the heating element and the heating element is likely to be damaged.

In addition, when measuring the water concentration in the test oil, it is preferable to shake and stir the test oil well to make it homogeneous in order to perform measurements with good reproducibility. If the oil is stirred, air bubbles will be included in the oil to be tested.
It is necessary to perform the measurement after removing this bubble. However, in the above-described apparatus, there is a problem in that when test oil containing air bubbles is introduced into the measurement cell, it takes a long time until the air bubbles are removed.

The present invention was developed in view of the above circumstances, and involves immersing a heating element in the oil to be tested in a measurement cell, and using the heating element to heat the oil near the heating element to a temperature higher than the boiling point of water. In this method, the water concentration in the oil is measured by generating water vapor bubbles at the contact surface between the oil and the heating element and detecting the water vapor bubbles with a sensor. To reduce the amount of energy required for heating as much as possible, and thus prevent damage to the heating element by preventing overvoltage from being applied to the heating element even when an electric heating element equipped with a filament or the like is used as the heating element. At the same time, in order to quickly remove air bubbles in the test oil that contains air bubbles by tinting and stirring, the inside of the measurement cell containing the test oil is reduced to a negative pressure state, and in this state water vapor bubbles are generated. The system is designed to detect this.

1-''L That is, in the present invention, the boiling point of water is lowered by creating a negative pressure inside the measurement cell, so the heating temperature of the heating element can be lowered, and therefore it takes less time to heat the heating element to a predetermined temperature. The amount of energy required can be reduced. Therefore, when an electric heating element equipped with a filament or the like is used as the heating element, the voltage supplied to the heating element can be reduced and overvoltage can be prevented from being applied to the heating element, resulting in damage to the heating element. can be prevented and extend its lifespan. Furthermore, in the present invention, since the inside of the measurement cell is under negative pressure, when the test oil containing air bubbles is introduced into the measurement cell, the air bubbles are degassed in a short period of time, so that the test oil is removed as a pretreatment. The oil can be further shaken and homogenized before the measurement, thus improving the usability of the measurement.

Next, examples will be shown to specifically explain the present invention.

Support-i @1 Figure shows an example of an apparatus used to carry out the measuring method of the present invention. In FIG. 1, parts having the same configuration as those in FIG. 4 are given the same reference numerals, and the explanation thereof will be omitted.

In FIG. 1, 18 is a sample container, and the sample container 18 contains test oil, and a stirrer 19 is inserted into the test oil, and the test oil is stirred by this stirring 8119. It looks like this. In addition, in this device, a one-way solenoid valve 21 and a three-way solenoid valve 15 are installed in the connecting pipe line 11 in order from the upstream side to the float switch 20, and a connecting pipe between the float switch 20 and the three-way solenoid valve 21 is installed. A pressure switch 22 is connected to the line 11. Further, one end of an atmospheric release pipe 23 is connected to the three-way solenoid valve 15 . Note that in this device, unlike the device shown in FIG. 4, a return pipe line and a bypass line are not provided.

When measuring the water concentration in test oil using this device, first the test oil in the sample container 18 is stirred by the stirrer 19 to make the test oil uniform. Next, the test oil in the sample container 18 is sucked up through the suction pipe 9 by the operation of the pump 10, and after the test oil fills the measurement cell and enters the float switch 20, the float switch 20 is activated to raise the liquid level. is detected, and when the liquid level reaches a predetermined position, the solenoid valve 18
occlude. After that, this state (the solenoid valve 13 is closed,
21.15 is open), the pump 10 continues to operate and enters the depressurization phase. And pressure switch 22
detects the pressure between the solenoid valves 13 and 21,
When the pressure during this period, that is, the pressure inside the measuring cell, reaches a predetermined negative pressure set in advance by a pressure switch, the solenoid valve 21 is closed and the operation of the pump 10 is stopped. Thereafter, the heating element 2 is heated to measure moisture content at 11 degrees Celsius. After the measurement is completed, the three-way Ill valve 15 is switched to connect the connecting pipe 11 and the atmosphere release pipe 23, and the 11i solenoid valves 13 and 21 are opened. is discharged into the sample container 18.

In the above-mentioned device, after filling the measuring cell with the oil to be tested, the pulp 13 is closed w1 and the pump 10 is operated to reduce the pressure inside the measuring cell. can be made negative pressure.

In the above-mentioned apparatus, the pressure inside the measuring cell is reduced by the operation of the pump 10, but other pressure reduction mechanisms may be adopted. Although a control section 17 is provided, the control section 17 may be omitted when driving manually, the heating element may be heated by steam instead of electric power, and other configurations may also be used. Various changes may be made without departing from the spirit of the invention.

Further, the negative pressure within the measurement cell can be set to any pressure convenient for measurement. In this case, it is preferable to always perform the measurement at the same pressure, so that the boiling point of water can always be the same and the measurement can be performed with good reproducibility.

As explained above, in the method for measuring the degree of moisture in oil according to the present invention, a heating element is immersed in the oil to be tested in a measurement cell, and the oil near the heating element is removed by the heating element. In the method of measuring 11 degrees of moisture in oil by heating water above the boiling point to generate water vapor bubbles on the contact surface between the oil and the heating element and detecting the water vapor bubbles with a sensor, the above measurement method is performed. By generating water vapor bubbles under negative pressure inside the cell, the boiling point of water can be lowered and the energy m required to heat the heating element to a specified temperature can be reduced. . Therefore, when an electric heating element equipped with a filament or the like is used as the heating element, the voltage applied to the heating element can be reduced, which prevents IIm of the electric heating element and extends its life. , even when heating with steam, the predetermined t! ! You can shorten the time it takes to heat up to a certain degree. In addition, even if the test oil containing air bubbles is introduced into the measurement cell by shaking or stirring, the air bubbles are quickly removed, so it is necessary to properly pre-process the test liquid by shaking and stirring to make it uniform. I can do it.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing an example of a device used to implement the measuring method of the present invention, FIGS. 2 and 3 are sectional views each showing a conventional measuring device, and FIG. 4 is a schematic diagram showing a conventional measuring device. It is. 2... Heating body, 2b... Filament. 3...Sensor, 4...Measuring mechanism, 7...Measuring cell. 10...Pump, 22...Pressure switch.

Claims (1)

[Claims] 1. A heating element is immersed in the oil to be tested in a measurement cell, and the heating element heats the oil near the heating element to a temperature higher than the boiling point of water to form a contact surface between the oil and the heating element. Along with generating water vapor bubbles,
The method for measuring the moisture concentration in oil by detecting water vapor bubbles with a sensor, characterized in that the water vapor bubbles are generated with negative pressure in the measurement cell. Moisture concentration measurement method. 2. The measuring method according to claim 1, wherein the oil to be tested is introduced into the measuring cell after being shaken and stirred.