JPH0718824B2 - Deposition point measuring method and apparatus - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an aviation fuel oil test method, and more particularly to a method and an apparatus for automatically measuring the precipitation point of aviation fuel oil.

[Prior Art] For the purpose of quality control of aviation gasoline and aviation turbine fuel oil, testing of aviation fuel oil is obligatory.
One of the test methods is a method of measuring the precipitation point.
This precipitation point test method is specified in JIS K2276, and according to this standard, "the precipitation point means that when the sample is cooled, the crystals of the hydrocarbons generated raise the temperature of the sample. It is the temperature at which it disappears. "

The deposition point was generally measured (JIS method) by using the tester shown in FIG. 6 as follows.

That is, about 25 ml of a sample is stored in a sample container 51, and cooled in a Dewar bottle 52 containing a refrigerant 53 while stirring with a stirring rod 54 until hydrocarbon crystals are deposited. If crystals are deposited, the sample container 51 is taken out of the Dewar bottle 52 and gradually heated while stirring, and the temperature at which the deposited hydrocarbon crystals completely disappear is detected by the thermometer 25 as the deposition temperature. .

Then, this detection was repeated until the difference between the crystal precipitation temperature and the disappearance temperature was within 3 ° C, and the disappearance temperature when it was within 3 ° C was defined as the precipitation point.

As a test method for automatically measuring the deposition point, a sample container similar to the sample container shown in FIG. 6 was used, and a change in the state of the sample in this container was used as a change in the reflectance of the sample surface. There is one disclosed in JP-A-62-173140 which detects and automatically measures the precipitation point based on this change.

[Problems to be solved] However, the former method (JIS method) among the above-mentioned conventional deposition point measuring methods uses a large amount of a sample of 25 ml for measurement, and therefore, even if the sample is stirred during measurement, the temperature is There is a problem that the distribution tends to be non-uniform and it is difficult to obtain high measurement accuracy. Further, since a large amount of sample is cooled and heated and the measurement is repeated until the difference between the precipitation temperature and the disappearance temperature is within 3 ° C., there is a problem that the measurement takes a long time.

On the other hand, the latter method of JP-A-61-173140 is excellent in that the deposition point can be automatically measured, but since a large amount of sample is used as in the former method, the problems of the former method I kept the points as they were. Further, in this method, since the deposition point is measured based on the change in reflectance of the sample surface, it is judged that the sample is completely crystallized only by the surface crystallization phenomenon of the sample, which is high. There was a problem that the measurement accuracy could not be obtained.

The present invention has been made in view of the above problems, the measurement of the deposition point, using a small amount of the sample, a method of measuring the deposition point that can be automatically and accurately performed in a short time and its The purpose is to provide a device.

[Means for Solving Problems] In order to achieve the above object, a method for measuring a deposition point of the present invention is such that a small amount of a sample having a known deposition point is stored in a sample chamber and light from a light source is emitted to the sample in the sample chamber. Directly incident through the fiber, and by directly receiving the light transmitted through the sample through the optical fiber, the process of obtaining the transmitted light amount at the deposition point and storing it as the judgment point, the sample of unknown deposition point in the sample chamber The amount of transmitted light is obtained by storing a small amount of light, cooling and heating, directly injecting light from a light source into the sample through an optical fiber, and directly receiving light transmitted through the sample through the optical fiber. Further, the amount of transmitted light is compared with the judgment point, the precipitation temperature and the disappearance temperature when the amount of transmitted light becomes the same as the judgment point are repeatedly detected, and the difference between the precipitation temperature and the disappearance temperature is a predetermined temperature. And a step of determining a disappearance temperature when the temperature falls within the range as a precipitation point.

Further, the deposition point measuring device of the present invention is formed in a measuring cell made of a metal block having good heat conduction, and a sample chamber for storing a small amount of sample and a temperature adjusting device for cooling and heating the sample in the sample chamber. A temperature sensor for measuring the sample temperature in the sample chamber, and the end portions of the optical fibers for light emission and light reception are arranged at positions facing each other across the sample chamber, and the measurement cell for the optical fiber for light emission is provided. A light source is arranged on the side of the input end that is remote, and a transmitted light amount detector in which a light receiving element is arranged on the side of the output end that is remote from the measuring cell of the optical fiber for receiving light, and the amount of transmitted light at the deposition point of the deposition point known sample is It is stored in advance as a judgment point, and the judgment point and the output from the detector are compared to obtain the precipitation temperature and the disappearance temperature of the sample with an unknown precipitation point, and the difference between the precipitation temperature and the disappearance temperature is within a certain temperature. Disappearance of time It is constituted comprising a control unit for determining the freezing point temperature.

[Embodiment] An embodiment of the present invention will be described below with reference to the drawings.

First, an embodiment of a deposition point measuring device will be described with reference to FIGS. 1 and 2.

FIG. 1 is a schematic overall view of the apparatus of the embodiment, and FIG. In these drawings, 10 is a measuring cell, 20 is a temperature control device, 30 is a detection unit, and 40 is a control unit.

The measurement cell 10 includes a sample chamber 11 that stores a small amount (for example, 2 to 3 ml) of a sample (hydrocarbon oil), an injection path 12, a discharge port 13, an air vent port 14, and an injection path that are connected to the sample chamber 11. It has an injector 15 for injecting the sample into the sample chamber 11 via 12. For this measuring cell 10, it is preferable to use aluminum or the like, which has good thermal conductivity and is resistant to corrosion.

The temperature controller 20 includes an electronic temperature controller 21 and a cool jacket 23.
have. Of these, the electronic temperature controller 21 is formed by a Peltier effect element in which a p-type semiconductor and an n-type semiconductor are joined with a metal, and is arranged on both sides of the measuring cell. This electronic temperature controller 21 utilizes the thermoelectric phenomenon of the Peltier effect element.By changing the direction of the current flowing through the Peltier effect element by the controller 22, heat is generated and absorbed to heat the sample. Cool down. On the other hand, the cool jacket 23 is also arranged on both sides of the measuring cell 10, and the refrigerant is circulated and supplied from the refrigerant tank 24 to the cool jacket 23 via the control valve 25.

The temperature control device 20 performs relatively strong cooling by flowing a refrigerant through the cool jacket 23, and an electronic temperature controller.
21 makes delicate temperature control of the sample under low temperature.

As shown in FIG. 2, the detection unit 30 includes a temperature sensor 31 (for example, a platinum thermometer) that detects the temperature of the sample stored in the sample chamber 11, and a transmitted light amount that detects the transmitted light amount of the sample. It is composed of a detector 32. Of these, the transmitted light amount detector 32
Are the optical fibers 33, 34 at positions facing each other across the sample chamber 11.
Is arranged directly, the light source 35 is provided at the input end of one optical fiber 33, and the light receiving element 36 is provided at the output end of the other optical fiber 34.

When the light source 35 and the light receiving element 36 are provided at positions apart from the measuring cell 10 via the optical fibers 33 and 34, the light source 35 and the light receiving element 36 are not adversely affected by the temperature of the measuring cell 10.

The control unit 40 is configured using a microcomputer or the like, and based on the output signals from the temperature sensor 31 and the transmitted light amount detector 32 and / or the data stored in a memory (not shown), the controller 22 Then, the control valve 25 and the like are controlled, and various data are compared, operated, and processed.

41 is an output unit such as a printer or a display,
The data output from the control unit 40 is printed or displayed.

Next, an example of a deposition point measuring method will be described with reference to FIGS.

Here, FIG. 3 is a flow chart showing the procedure of the method of the embodiment, FIG. 4 is a conceptual diagram at the time of sample injection, and FIG. 5 is a time chart showing the relationship between sample temperature and the amount of transmitted light.

The deposition point is measured by the JIS method or the like, and a sample of which deposition point is known is injected into the sample chamber 11 of the measuring cell 10 to store 2-3 ml.

Through the optical fiber 33 arranged on one side of the sample chamber 11,
Light enters the sample from the light source 35, and the amount of transmitted light at the sample deposition point is detected by the light receiving element 36 via the optical fiber 34 arranged on the other side of the sample chamber 11. The amount of transmitted light detected at this time is stored in the memory of the control unit 40 as a determination point (voltage signal).

A sample with a known deposition point is discharged from the measurement cell 10, and a new sample with an unknown deposition point is injected into the sample chamber 11 in the manner shown in FIGS. 4 (a) and 4 (b) to store 2-3 ml.

While cooling the sample in the sample chamber 11, light is made incident on the sample from the light source 35, and the amount of transmitted light at this time is detected by the light receiving element 36.

I. At the start of cooling, the sample is still transparent and has a large amount of transmitted light.

B. After a while after cooling is started, crystals in the sample start to be generated and the amount of transmitted light gradually decreases.

C. As cooling progresses, crystals are sufficiently precipitated in the sample and the amount of transmitted light decreases.

(See (a), (b), and (c) in FIG. 5). The control unit 40 compares the amount of transmitted light received by the light receiving element 36 during the continuous cooling with the determination point, and determines the sample temperature when the amount of light is the same as the determination point. Store as the precipitation temperature.

When the amount of transmitted light reaches 20% by cooling the sample, the control unit 40 switches the electronic temperature controller 21 to the heating mode via the controller 22 and starts heating the sample.

D. After starting heating for a while, the crystals in the sample start to disappear, and the amount of transmitted light gradually increases.

E. As the heating progresses, the crystals in the sample disappear completely and the amount of transmitted light increases.

(Refer to D and E in FIG. 5) The control unit 40 compares the amount of transmitted light received by the light receiving element 36 during the heating continuation with the determination point, and sets the sample temperature when the amount of light is the same as the determination point as the disappearance temperature. Remember.

When the amount of transmitted light reaches 90% by heating the sample, the control unit 40 switches the electronic temperature controller 21 to the cooling mode via the controller 22.

The above-described cooling and heating of the sample are repeated until the difference (T) between the precipitation temperature and the disappearance temperature falls within a predetermined temperature, for example, within 3 ° C. Then, the disappearance temperature when the difference (T) between the precipitation temperature and the disappearance temperature falls within 3 ° C. is determined as the precipitation point of the tested sample.

Since the amount of the sample injected and stored in the sample chamber 11 is as small as 2-3 ml, the temperature of the sample can be adjusted by cooling and heating in a short time.

Samples with known deposition points (measured by JIS method: deposition point-4
(9.5 ° C.) was measured by the above-described apparatus and method of the embodiment of the present invention while changing the cooling rate, and the following results were obtained.

Precipitation point measured by cooling rate (℃ / min) (℃) 100 −49.3 200 −49.6 Thus, there was only a slight change in the measured value when the cooling rate was doubled. Also, in the JIS method, since the numbers below the decimal point are summarized in 0.5 units, no significant difference in accuracy was observed between the results obtained by the JIS method and there was no problem.

The present invention is not limited to the above embodiments, but can be variously modified within the scope of the gist.

For example, in the method of measuring the deposition point, several kinds of samples having different deposition points may be measured in advance and stored as a calibration curve.

Further, in the measuring device of the deposition point, the mode of cooling and heating of the temperature control device 20, the mode other than the above embodiment,
Means may be used, and the positions of the light source and the light receiving element are
It may be placed close to the sample chamber within a range that is not adversely affected by the temperature of the measurement cell.

[Effects of the Invention] As described above, according to the method for measuring the deposition point of the present invention, the automatic measurement of the deposition point can be performed accurately in a short time.

Further, according to the deposition point measuring apparatus of the present invention, automatic measurement of the deposition point can be accurately performed in a short time with a simple apparatus.

[Brief description of drawings]

FIG. 1 is a schematic overall view of the apparatus of the embodiment, FIG. 2 is an enlarged cross-sectional view of an essential part of the apparatus of FIG. 1, FIG. 3 is a flow chart showing the procedure of the method of the embodiment, and FIG. FIG. 5 is a time chart showing the relationship between the sample temperature and the amount of transmitted light.
The figure shows an overall view of a conventional deposition point measuring instrument. 10: Measurement cell, 11: Sample chamber 20: Temperature controller, 21: Electronic temperature controller 22: Controller, 23: Cooling jacket 30: Detection part, 31: Temperature sensor 32: Transmitted light intensity detector, 35: Light source 36 : Light receiving element, 40: Control unit

Continuation of front page (56) Reference JP-A-59-43337 (JP, A) JP-A-58-7550 (JP, A) JP-A-61-173140 (JP, A)

Claims (2)

[Claims] 1. A small amount of a sample having a known deposition point is stored in a sample chamber, light from a light source is directly incident on the sample in the sample chamber through an optical fiber, and light transmitted through the sample is transmitted through the optical fiber. By directly receiving the light, the amount of transmitted light at the deposition point is calculated and stored as a judgment point. A small amount of a sample with an unknown deposition point is stored in the sample chamber and cooled,
While heating, the light from the light source is directly incident on the sample through the optical fiber, and the light transmitted through the sample is directly received through the optical fiber to obtain the transmitted light amount. The judgment points are compared, the precipitation temperature and disappearance temperature when the amount of transmitted light becomes the same as the above judgment points are repeatedly detected, and the disappearance temperature when the difference between the precipitation temperature and the disappearance temperature is within a predetermined temperature And a step of determining as the deposition point, and a method of measuring the deposition point, which comprises: 2. A sample chamber, which is formed in a measuring cell made of a metal block having good heat conduction and stores a small amount of sample, a temperature control device for cooling and heating the sample in the sample chamber, and a sample temperature in the sample chamber. And a temperature sensor for measuring the temperature of the sample chamber, and the ends of the optical fibers for light emission and light reception are arranged at positions facing each other across the sample chamber, and a light source is provided on the input end side of the optical fiber for light emission, which is separated from the measurement cell. Place
And the transmitted light amount detector in which a light receiving element is arranged on the output end side of the light receiving optical fiber away from the measurement cell, and the transmitted light amount at the deposition point of the sample whose deposition point is known is stored as a determination point in advance, and this determination point Control to determine the deposition temperature and the disappearance temperature of the sample whose deposition point is unknown and to determine the disappearance temperature when the difference between the precipitation temperature and the disappearance temperature is within a certain temperature as the precipitation point. A deposition point measuring device, characterized in that