JP3040933B2 - Flash point measuring device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flash point measuring apparatus and can be used for quality control of petroleum products such as volatile oil and light oil distilled from crude oil.

[0002]

2. Description of the Related Art Conventionally, there is known a flash point measuring device which ignites a test substance heated in a closed measuring chamber with a discharge electrode and detects that the test substance has ignited due to a pressure increase due to combustion ( JP-A-5-17771). Such a flash point measuring device utilizes the fact that the pressure in the measurement chamber rises sharply due to the combustion of the test substance, thereby reliably grasping the timing at which the test substance ignites and measuring the temperature of the test substance at the time of ignition. It can be detected accurately. In addition, if an air supply pipe for exchanging air in the measurement chamber due to combustion, and a pipe or a transfer path for exchanging the test substance with another substance are provided in the flash point measurement device, the measurement chamber will not be disassembled. In addition, the flash points of a plurality of types of test substances can be continuously measured, and the continuous measurement can be rapidly performed.

[0003]

However, when measuring the flash point of a relatively heavy oil such as light oil, the oil is liable to incompletely burn, and the carbon generated by the incomplete combustion causes a relatively short time. This causes the discharge electrode to become dirty. For this reason, if the measurement of the flash point is repeated many times, the ignition power of the discharge electrode becomes unstable due to contamination, so that the timing at which the test substance ignites fluctuates, and there is a problem that the dispersion of measured values increases. . On the other hand, it is conceivable to clean the discharge electrode and remove carbon attached to the discharge electrode before the measured values vary, but since cleaning of the discharge electrode requires disassembly of the measurement chamber, the discharge electrode must be disassembled. If the cleaning is performed, there is a problem that rapid continuous measurement cannot be performed.

[0004] It is an object of the present invention to provide a flash point measuring apparatus which enables rapid continuous measurement irrespective of the type of a substance to be tested and also reduces the dispersion of measured values.

[0005]

SUMMARY OF THE INVENTION The present invention relates to a flash point measuring apparatus for igniting a test substance heated in a closed measuring chamber with a discharge electrode and detecting the ignition of the test substance by a pressure increase due to combustion. And a gas supply pipe for blowing gas to the discharge electrode. In the above,
The gas blown to the discharge electrode desirably contains oxygen, and air in the atmosphere can be used as it is.

[0006]

According to the present invention, by blowing gas to the discharge electrode, carbon adhering to the discharge electrode is removed, and the carbon generated by incomplete combustion is prevented from adhering to the discharge electrode. In addition, the discharge electrodes are less likely to become dirty. Therefore, even if the measurement of the flash point is repeated many times, the ignition power of the discharge electrode does not become unstable, the timing of igniting the test substance becomes stable, the dispersion of the measured values is reduced, and the discharge electrode is Since the need for frequent cleaning is eliminated, rapid continuous measurement can be performed, thereby achieving the above object. If oxygen-containing gas is blown onto the discharge electrode immediately after the combustion of the test substance is completed, the carbon that has adhered to the heated discharge electrode is completely burned and removed from the discharge electrode. Is further reduced, and the frequency of cleaning the discharge electrode is further reduced.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a flash point measuring device 1 according to a first embodiment of the present invention. In the figure, a flash point measuring device 1
Is configured to include a container 12 and a lid 13 that seal the measurement chamber 11 that stores the test substance 2, and a heat-insulating container 3 that stores the container 12 and the lid 13. The container 12 is a thick-walled container formed of a material having good heat conductivity such as aluminum, and has a concave portion serving as the measurement chamber 11 formed therein.
The lid 13 is a thick lid made of a material having good heat conductivity, such as aluminum, similarly to the container 12. The lower surface of the lid 13 in the drawing can be in close contact with the upper surface of the container 12 in the drawing. The heat insulating container 3 is divided into a bottom portion 3A that stores the container 12 and a lid portion 3B that stores the lid 13. Each of the bottom 3A and the lid 3B is formed by filling a hollow member with a cotton-like heat insulating material. Note that a pressing device (not shown) is arranged below the container 12. This pressing device presses the container 12 toward the lid 13 via the bottom 3A of the heat insulating container 3. The container 12 and the lid 13 are brought into close contact with each other by the pressing of the pressing device, so that the measurement chamber 11 is sealed.

An electric heater 20 is wound around the peripheral surface of the lid 13, and the test substance 2 stored in the measurement chamber 11 is heated by the electric heater 20. Inside the cover 13, a temperature sensor 21 for detecting the temperature of the cover 13 is provided. The temperature sensor 21 is fixed to the lid 13 so that the heat of the lid 13 is transmitted well. Based on the temperature detected by the temperature sensor 21, the electric heater 20 is manually or automatically operated.
The heating intensity is adjusted. A temperature sensor 22 for detecting the temperature of the test substance 2 is provided below the lid 13 in the drawing.
And a pair of discharge electrodes 23A and 23B used for ignition. The temperature sensor 22 is suspended from the lower surface 13A of the lid 13 in the drawing, and reaches the inside of the test substance 2. As a result, the temperature of the test substance 2 is accurately detected by the temperature sensor 22. The discharge electrodes 23A and 23B are connected to a general ignition coil and generate sparks for ignition. Note that the tips of the discharge electrodes 23A and 23B are arranged about 2 mm above the surface of the test substance 2.

Further, the lid 13 is provided with a pressure guiding tube 24 penetrating through the central portion of the lid 13 and a gas supply tube 25 penetrating above the discharge electrodes 23A and 23B. The pressure guide tube 24 transmits the internal pressure of the closed measurement chamber 11 to a pressure sensor 26 provided outside the device 1. The pressure sensor 26 is
It is composed of a piezoelectric element or the like, and converts pressure into a predetermined electric signal. This pressure sensor 26 and the aforementioned temperature sensor
Reference numerals 21 and 22 are electrically connected to an automatic recording device (not shown). The gas supply tube 25 blows air to the discharge electrodes 23A and 23B. The end of the gas supply pipe 25 on the measurement chamber 11 side is a tapered air nozzle 25A. Gas supply pipe
The outside end of 25 is connected to an air supply means such as a roots blower (not shown). With this air supply means, air in the atmosphere is set to a predetermined pressure and blows out vigorously from the air nozzle 25A of the gas supply pipe 25.

In this embodiment, the flash point is measured in the following procedure. First, the container 12 is opened, and the measuring chamber 11 is opened.
After filling the test substance 2, mainly a liquid test substance,
When a pressing device (not shown) is driven to raise the container 12 to be in close contact with the lid 13 and to close the measurement chamber 11, the electric heater 20 of the lid 13 is operated to slowly heat the test substance 2. Then
When the temperature of the test substance 2 reaches a predetermined temperature close to the flash point, each time the temperature rises by a predetermined value, the discharge electrodes 23A, 23B
A high voltage is applied to the sparks to generate sparks. And the discharge electrode
When the test substance 2 is ignited and burned by the sparks of 23A and 23B, the pressure in the measurement chamber 11 rises rapidly. This pressure increase is detected by the pressure sensor 26. When the pressure value detected by the pressure sensor 26 suddenly rises, the automatic recording device described above uses the temperature sensor at the time when the pressure value starts to rise sharply.
The temperature value of 22 is recorded as the flash point of analyte 2. Immediately after the combustion of the test substance 2 is completed, air is blown from the air nozzle 25A of the gas supply pipe 25 to the discharge electrodes 23A and 23B to clean the discharge electrodes 23A and 23B. At this time, the discharge electrode
Carbon attached to 23A and 23B is removed by wind pressure. In addition, since the discharge electrodes 23A and 23B are heated and heated by the combustion, the carbon attached to the high-temperature electrodes 23A and 23B immediately after the combustion completely burns by the supply of air containing oxygen. Is also removed by Thereafter, the above-described pressing device is driven, the container 12 is lowered, the lid 13 is opened, and the measuring chamber is opened.
The burned air in 11 is replaced with fresh air, the test substance 2 is replaced if necessary, and the next flash point measurement is started.

According to the above-described embodiment, the following effects can be obtained. That is, since air was blown to the discharge electrodes 23A and 23B, the carbon adhered to the discharge electrodes 23A and 23B was removed, and the adhesion of carbon generated by incomplete combustion to the discharge electrodes 23A and 23B was suppressed. , Discharge electrode
23A and 23B are less likely to become dirty. Therefore, no matter how many times the measurement of the flash point is repeated, the ignition power of the discharge electrodes 23A and 23B does not become unstable, the timing of igniting the test substance 2 becomes stable, and the dispersion of the measured values can be reduced. Discharge electrodes 23A, 23B
Is less frequent, and rapid continuous measurement can be performed.

Further, since air containing oxygen is blown onto the heated discharge electrodes 23A and 23B immediately after the combustion of the test substance 2 is completed, the carbon adhering to the discharge electrodes 23A and 23B is completely removed. It is removed by burning, and from this point, the dispersion of measured values can be reduced, and the frequency of cleaning the discharge electrodes 23A and 23B can be reduced. In addition, air has no effect on subsequent measurements and is inexpensive,
Flash point measuring device 1 without impairing the speed of continuous measurement
Running cost can be reduced.

FIG. 2 shows a second embodiment of the present invention. In this embodiment, the container 12 for exchanging the test substance 2 by opening and closing the lid 13 in the first embodiment is a container 30 in which the exchange of the test substance and air is automatically performed in a closed state. Things. Hereinafter, the second embodiment will be described.
In the following description, the same members as those already described are denoted by the same reference numerals, and description thereof will be omitted or simplified. The container 30 is an upper and lower cylindrical container having a reduced diameter on the lower side in the figure. The upper side of the container 30 in the figure is a measuring section 31 having the measuring chamber 11 for storing the test substance 2 therein. On the other hand, the lower side of the container 30 in the figure is a heating unit 32 having the electric heater 20 for heating the test substance 2 therein.

The measurement section 31 is provided with a pair of discharge electrodes 23A and 23B extending from the side wall 33 toward the center of the measurement chamber 11 and facing each other at a predetermined interval. Discharge electrode 23
Above A and 23B, a pressure guiding tube 24 for transmitting the pressure in the measurement chamber 11 to the pressure sensor 26 is connected. Below the discharge electrodes 23A and 23B, a temperature sensor 22 such as a thermocouple for detecting the temperature of the test substance 2 and a test substance 2 stored in a larger amount than a predetermined amount are provided.
A discharge pipe 34 is provided for overflowing the surplus. Between the discharge electrodes 23A and 23B and the liquid surface of the test substance 2,
A baffle plate 35 is provided.
The sparks of the discharge electrodes 23A and 23B are prevented from jumping directly. The upper side of the measuring section 31 is closed by a lid section 36.
An air chamber 37 is provided on the upper surface of the lid 36 in the drawing. A gas supply pipe 25 is connected to the air chamber 37, and a pair of air nozzles 25A for blowing air toward each of the discharge electrodes 23A and 23B is opened.

On the other hand, the lower opening of the heating unit 32 is closed by a bottom cover 38. The bottom cover 38 is provided with a hollow protrusion 38A extending upward, and an electric heater is provided inside the protrusion 38A.
20 are stored. The test substance 2 is also stored between the convex portion 38A and the side wall 39 of the heating section 32, so that the heat of the electric heater 20 is efficiently transmitted to the test substance 2. The side wall 39 of the heating section 32 is provided with an air supply pipe 41 for replacing the air in the measurement chamber 11 and a test substance supply pipe 42 for replacing the test substance 2 in the measurement chamber 11. . The air supply pipe 41 is connected to an air supply source (not shown) via an electromagnetic valve 43. The solenoid valve 43 is
The connection with the air supply source is switched from one of the air supply pipe 41 on the heating section 32 side and the other to the gas supply pipe 25 on the measurement section 31 side. On the other hand, the gas supply pipe 25 is connected to the electromagnetic valve 43 via the electromagnetic valve 44 and the pipe 45. Solenoid valve 44
Is a pipe 46 whose end is open to the atmosphere, and a solenoid valve 43
The connection of the gas supply pipe 25 is switched from one of the pipes 45 connected to the side to the other. These solenoid valves 43, 44
Operate simultaneously, and normally, the electromagnetic valve 43 connects the air supply source to the air supply pipe 41, and the electromagnetic valve 44 connects the gas supply pipe 25 to the atmosphere side. On the other hand, from the completion of combustion of the test substance 2 until a predetermined time elapses,
The electromagnetic valves 43 and 44 connect the air supply source and the gas supply pipe 25.

Next, the operation of this embodiment will be described.
When the flash point measuring device is started in a state where the old test substance 2 is stored in the measurement chamber 11, the flash point measuring device performs an operation of replacing the test substance 2. When the test substance 2 is exchanged, the test substance 2 is supplied from the test substance supply pipe 42 to the measurement chamber 11 as shown in FIG. As a result, the old test substance 2 overflows and is discharged from the discharge pipe 34. At this time, air is supplied from the air supply pipe 41.
This air rises inside the test substance 2, and promotes the rise of the old test substance 2 stagnating at the bottom of the heating unit 32, so that the exchange time of the test substance 2 is reduced. The air that has come out of the liquid surface of the test substance 2 into the air is the air nozzle 25A and the gas supply pipe 2.
5, and is opened to the atmosphere through the pipe 46. When the replacement of the test substance 2 is completed, the electric heater 20 is started, and the electric heater 20 starts heating the test substance 2. During the heating of the test substance 2, air is supplied from the air supply pipe 41, and the excess air in the measurement chamber 11 emits the vapor of the test substance 2 as shown in FIG. It is released to the atmosphere along with it.

Next, when the temperature of the test substance 2 reaches a predetermined temperature close to the flash point, every time the temperature rises by a predetermined value, a high voltage is applied to the discharge electrodes 23A and 23B,
Sparks occur between A and 23B. When the temperature of the test substance 2 reaches the flash point, the test substance 2 is ignited by the sparks of the discharge electrodes 23A and 23B, and as shown in FIG. Burn. Due to the combustion of the test substance 2, the pressure in the measurement chamber 11 rises rapidly. This pressure rise is detected by the pressure sensor 26, the combustion of the test substance 2 is detected by the pressure rise, and an automatic recording device (not shown) records the temperature at the time of ignition. Immediately after the detection of the combustion, the solenoid valves 43 and 44 operate, and as shown in FIG. 3D, the supply of air to the gas supply pipe 25 side is started and the air supply to the air supply pipe 41 side is started. Supply stops. Here, the combustion of the test substance 2 is instantaneous, and the air blowing out from the air nozzle 25A is slightly delayed from the operation of the solenoid valves 43 and 44. Discharge electrode 23
A, 23B will be sprayed. The air from the air nozzle 25A is discharged for a predetermined time, for example, 2 seconds.
To clean the discharge electrodes 23A and 23B. Thereafter, when the flash point is measured for another test substance 2, the above operation is repeated again.

In this embodiment as well, the first
The same operation and effect as those of the embodiment can be obtained. In addition, since the air and the test substance 2 in the measurement chamber 11 can be automatically exchanged, the effect that the flash point measurement can be completely automated can be added. it can.

Next, the effects of the present invention will be described based on specific experimental examples. [Experimental Example] This experimental example is an experiment for measuring the flash point of light oil with the flash point measuring device of the second embodiment. In this experimental example, the measurement of the flash point of light oil is repeated as much as possible. [Comparative Example] In this comparative example, the direction of the air nozzle 25A of the gas supply pipe 25 in the second embodiment was changed, and air was discharged.
This is an experiment in which a flash point of a light oil having the same properties as those of the above-mentioned experimental example is measured by a flash point measuring device which is configured not to directly hit 23A and 23B. Also in this comparative example, the measurement of the flash point of light oil is repeated as much as possible. In the above-described experimental examples and comparative examples, each time one measurement is completed, after replacing the burned air in the measurement chamber with fresh air, after adjusting the measurement conditions, the next measurement is performed. I do. [Experimental Results] In the experimental example, even if the measurement was repeated 100 times, the amount of carbon adhering to the discharge electrodes 23A and 23B was very small, and the measurement could be continued without change. Further, the dispersion of the measured values was small, and the maximum was ± 2 ° C.
On the other hand, in the comparative example, when the 30th measurement is completed,
A large amount of carbonaceous material adhered to the discharge electrodes 23A and 23B, and the discharge electrodes 23A and 23B could not be discharged, and no further measurement could be performed. In addition, the dispersion of the measured values gradually increased, and in the 21st and subsequent measurements, the dispersion of the measured values was up to ± 7 ° C.

Although the present invention has been described with reference to the preferred embodiments, the present invention is not limited to these embodiments, and various improvements and design changes may be made without departing from the spirit of the present invention. It is possible. For example, the test substance is not limited to light oil, but may be other petroleum products such as gasoline or kerosene, and is not limited to a liquid, and may be a solid. In short, any substance containing a volatile component may be used. .

The gas blown to the discharge electrode is not limited to air, but may be an inert gas such as nitrogen. However, the effect described in the above embodiment can be obtained by using an oxygen-containing gas such as air.

[0022]

As described above, according to the present invention, rapid continuous measurement can be performed irrespective of the type of the test substance, and variation in measured values can be reduced.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a first embodiment of the present invention.

FIG. 2 is a sectional view showing a second embodiment of the present invention.

FIG. 3 is a diagram for explaining the operation of the second embodiment.

[Explanation of symbols]

 1 Flash point measuring device 2 Test substance 11 Measurement chamber 23A, 23B Discharge electrode 25 Gas supply pipe

Claims (3)

(57) [Claims] 1. A flash point measuring device for igniting a test substance heated in a closed measuring chamber by a discharge electrode and detecting the ignition of the test substance by a pressure increase due to combustion, wherein a gas is blown to the discharge electrode. A flash point measuring device comprising a gas supply pipe. 2. The flash point measuring device according to claim 1, wherein the gas blown to said discharge electrode contains oxygen. 3. The flash point measuring device according to claim 1, wherein the gas blown to said discharge electrode is air.