JPH08145921A - Measuring equipment of flammability limits - Google Patents

Abstract

PURPOSE: To enable the measurement of lower and upper flash points of an organic substance at an arbitrary temperature and flammability limit oxygen concentration thereof with ease, accuracy and excellent reproducibility by a method wherein inactive gas and oxygen or air of arbitrary concentrations are introduced into a sealed vessel and heated to a desired temperature by a heating device and the measuring is conducted. CONSTITUTION: A pressure inside a sealed vessel 1 being reduced by a vacuum pump, inactive gas and oxygen or air are introduced 13 into the vessel 1 and an oxygen (air)-inactive gas mixture of prescribed oxygen concentration is produced. Next, the needle of a syringe in which a sample (organic substance) is put is inserted into a cork 2 for sealing, the sample in an appropriate quantity is injected into the bottom part of the vessel 1, the temperature of oil 8 in an oil bath 7 is raised with agitation 6, and when the temperature of the sample and that of the mixed gas reach desired temperatures, explosion is made to occur by a discharge between electrodes 4. By this explosion experiment, a vapor pressure and the explosion temperature of an arbitrary organic substance at an arbitrary oxygen temperature can be measured and the flammability limit oxygen temperature and the lower and upper flash points of the organic substance can be measured with excellent reproducibility.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention makes it possible to easily determine the lower flash point and upper flash point and the explosive limit oxygen concentration of a mixed sample gas in which a vapor of an organic substance is mixed with oxygen diluted with an inert gas to any concentration Moreover, the present invention relates to an explosion limit region measuring device that measures accurately.

[0002]

2. Description of the Related Art Conventionally, the problems to be solved by the invention
As a means for measuring the flash point of organic substances, ASTM, I
Many devices and measurement methods approved by SO and JIS are known. For example, the flash point measurement by JIS is
"Tag closed flash point measuring device (JIS K 253
9) ”,“ Penski Martens flash point measuring device (JIS
K 2265) ”,“ Cleveland open-type flash point measuring device (JIS K 2274) ”, and the like, in principle, the pilot frame (flame) is brought close to the organic matter.

However, in the open type, the volatile components are vaporized, and in the closed type, the temperature of the lid is delayed with time and the flash point is increased due to the decrease in condensation, so that an accurate measurement cannot be performed. Further, these devices have problems that an arbitrary mixed gas cannot be used as a gas, and that the flash point can only measure the lower limit of explosion.

Further, in JP-A-60-119453, JP-A-60-252249, and JP-A-5-172771, attempts have been made to improve such a problem. The flash point measuring device has problems that the device itself is complicated and that any mixed gas cannot be used. As a result, when performing chemical reactions, etc., it is not possible to measure the temperature at which an organic substance explodes, the mixing ratio of inert gas and oxygen, etc. Since it cannot be measured, it only functions as a flash point measuring device.

On the other hand, it is said that it is difficult to obtain an accurate measured value in the measurement of the "top flash point" which is an important value in the measurement of the explosion limit. Yagyu et al. Measure the flash point by a gas flow method using a combustion cylinder (Shozo Yagyu, Institute of Industrial Safety, "Relationship diagram between flash temperature and explosion limit (Vol. 1)", 1986). However, this method uses a complicated device and cannot be said to be a very simple type. Further, since it is not possible to freely prepare a mixed gas, there is a problem that only the flash point can be measured in an air system.

The present invention has been made in view of the above circumstances, and is an explosion in which the lower and upper flash points and the explosion limit oxygen concentration in an arbitrary mixed gas of organic substance vapor can be easily and reproducibly measured. An object is to provide a limit area measuring device.

[0007]

In order to achieve the above object, the present invention measures the lower flash point and upper flash point of a mixed sample gas of organic vapor, an inert gas and oxygen or air, and the explosion limit oxygen concentration. Which has an explosion zone for the mixed sample gas and is equipped with a means for detecting the pressure due to this explosion, a temperature measuring device for measuring the temperature of the explosion zone, and An ignition electrode provided, a heating device for heating the explosion region to a predetermined temperature, one end of which is connected to the closed container, the other end of which is connected to a vacuum device, and an inert gas introducing valve and There is provided an explosion limit region measuring device comprising an oxygen or air introduction valve and a gas introduction pipe for supplying an inert gas and oxygen or air to the explosion region.

As a preferred embodiment thereof, there is provided an apparatus for measuring the lower flash point and upper flash point of a mixed sample gas of an organic vapor, an inert gas and oxygen or air, and the explosion limit oxygen concentration, wherein Has an explosive area for sample gas,
Due to this explosion, a hermetically sealed container that is detachably attached, a thermocouple for measuring the temperature in the explosion area, an ignition electrode arranged in the explosion area, and the sealed container are immersed in the explosion area. An oil bath for heating to a predetermined temperature, one end of which is connected to the closed container, the other end of which is connected to a vacuum pump, and an inert gas introducing valve and an oxygen or air introducing valve are respectively interposed. And a gas introduction pipe for introducing an inert gas and oxygen or air into the explosion region.

[0009]

The apparatus of the present invention can introduce an inert gas and oxygen or air into an airtight container from the above gas introduction pipe at any concentration, and the explosion limit of vapor of an organic substance at a desired temperature can be controlled by a heating device. The oxygen concentration can be measured, and the lower flash point and the upper flash point of the organic substance at the desired oxygen concentration can be measured easily and accurately.

That is, according to the present invention, under various experimental conditions, any vapor of a given organic substance can easily form an ignitable mixture with oxygen diluted with an inert gas, so that any vapor can be easily formed. A mixed gas can be supplied and the ignition temperature can be accurately controlled. In addition, when performing a chemical reaction, the temperature at which an organic substance causes an explosion, the mixing ratio of inert gas and oxygen, etc. can be measured easily and accurately, and the explosion limit oxygen concentration of the test substance can be measured in various ways. It enables measurement at the temperature.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

In the figure, reference numeral 1 is a closed container made of stainless steel, and this container 1 has a cylindrical container body 1a having a lower end surface closed and a flange portion 1b at an upper end portion, and a flange portion 1d at a lower end portion. It consists of a small diameter cylindrical neck 1c,
Both the flange portions 1b and 1d are fixed and connected with a bolt 1e, and an upper end opening portion of the neck body 1c is airtightly closed by a cork plug (sealing plug) 2 being fitted therein. The inside of the main body 1a of the container 1 is formed as an explosion zone 1f, and a thermocouple 3 for measuring the temperature of the explosion zone 1f is arranged so as to be movable in the vertical direction in the main body 1a, and for ignition. A pair of spark electrodes 4, 4
However, the closer to the surface of the organic matter, the more accurate the saturated vapor pressure of the organic matter becomes, so the lower part inside the main body 1a (the lower part of the explosion zone 1f)
Are arranged so as to face each other with their tips separated from each other by several mm. These spark electrodes 4 and 4 are connected to the neon transformer 5, and when the neon transformer 5 is turned on, a discharge is generated between the electrodes 4 and 4. In the figure, 6 is a magnetic stirrer.

Reference numeral 7 in the drawing denotes an oil bath containing oil 8 therein, and the closed container 1 is immersed in the oil 8 with the upper portion of the neck 1c thereof protruding from the liquid surface of the oil 8. Has been done. Further, 9 is a heater, 10 is a thermometer, and these heater 9 and thermometer 10 are connected to a temperature controller 11, respectively, and the oil 8 is controlled to a predetermined temperature. In addition, 12 is a stirrer.

Further, 13 is a gas introducing pipe, and this introducing pipe 1
One end of 3 is connected to the side portion of the main body 1a, and the inside of the introduction pipe 13 and the explosion area 1f communicate with each other. The other end of the introduction pipe 13 is connected to a vacuum pump 14, and the introduction pipe 13 is provided with an inert gas introduction valve 15, an oxygen or air introduction valve 16, and a pressure sequentially from the other end side to the one end side. A total of 17 and a shutoff valve 18 are provided. The inert gas introducing valve 15 is connected to an inert gas cylinder 20 via a connecting pipe 19, and the oxygen or air introducing valve 16 is connected to the other end of an air inflow pipe 21 having one end open. ing. A cooling pipe 22 is provided between the pressure gauge 17 and the shutoff valve 18. The cooling pipe 22 is arranged to prevent organic vapor from flowing into the upstream side of the introduction pipe 13, and cools the outer jacket of the cooling pipe 22 with water.

When measuring the explosion limit oxygen concentration of a sample using the above apparatus, first, the valves 15, 16 and 18 are operated so that the inside of the container 1 and the vacuum pump 14 are in communication with each other, and the vacuum pump 14 is operated. After depressurizing the inside of the container 1, the valve 15 is switched so that the cylinder 20 communicates with the inside of the container 1, and the inert gas is introduced into the container 1 at a predetermined pressure while observing the pressure gauge 17. Next, when the valve 15 is closed and the valve 16 is opened, air is introduced into the container 1 from the air inflow pipe 21. In this state, the valve 18 is closed. Therefore, an oxygen (air) -inert gas mixed gas having a predetermined oxygen concentration can be formed by the above operation.

Next, a sample for measuring the explosive limit oxygen concentration was prepared by preparing an oxygen-inert gas mixed gas as described above, and then placed in a syringe, and the needle was inserted into the cork stopper 2 to spark electrode 4, An appropriate amount is poured into the container 1 so as not to cover 4. While stirring the sample injected into the bottom of the container 1 with the magnetic stirrer 6, the temperature of the oil 8 in the oil bath 7 is gradually raised, while measuring the sample temperature in the container 1 and the temperature of the mixed gas, Adjust the explosion limit temperature to be measured. After confirming that the temperature of the sample and the temperature of the mixed gas are the same, the neon transformer 5 is turned on to generate a discharge between the electrodes 4 and 4. At this time, when an explosion occurs, the cork stopper 2 flies from the neck 1c by the blast, and the pressure of the container 1 is released. If there is no explosion, repeat the explosion experiment by changing the temperature again.

Therefore, by the above-described explosion experiment, the vapor pressure of any organic substance and the explosion temperature at any oxygen concentration can be measured, and the explosion limit oxygen concentration, lower and upper flash points of the organic substance can be easily and accurately determined. It can be measured and its reproducibility is also good.

[Experimental Example] Next, an experimental example using the above apparatus will be described.

In order to measure the explosive limit oxygen concentration, 20 g of 4 samples of p-xylene, acetic acid, kerosene, and pentafluoropropanol were taken as organic substance samples, and nitrogen and carbon dioxide were used as inert gases. did.

Table 1 shows the results of measurement of the upper and lower flash points when air is used. From this result, it was found that the lower flash point is lower than the JIS flash point, the scattering of flash vapor, which is a drawback of the tag closed type, is suppressed, and accurate flash point measurement is possible. Moreover, the upper flash point was in agreement with the result measured by Yagyu et al., Indicating that the upper flash point can be easily measured with this device.

[0021]

[Table 1]

3 to 6 and Table 2 show the results of measurement of the explosion limit oxygen concentration using nitrogen and carbon dioxide as the inert gas. From these results, it was found that the use of the present apparatus makes it possible to easily measure the explosion limit oxygen concentration.

[0023]

[Table 2]

[0024]

According to the apparatus of the present invention, the lower and upper flash points and the explosion limit oxygen concentration of an arbitrary organic substance at various oxygen concentrations can be accurately measured easily and reproducibly.

[Brief description of drawings]

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

FIG. 2 is a partially omitted perspective view of the same example.

FIG. 3 is a graph showing an explosive region of p-xylene.

FIG. 4 is a graph showing an explosion region of acetic acid.

FIG. 5 is a graph showing an explosion region of kerosene.

FIG. 6 is a graph showing the explosion region of pentafluoropropanol.

[Explanation of symbols]

 1 Airtight container 1f Explosion area 2 Cork stopper 3 Thermocouple 4 Electrode 7 Oil bath 13 Gas inlet pipe 14 Vacuum pump 15 Inert gas inlet valve 16 Oxygen or air inlet valve 20 Inert gas cylinder 21 Air inlet pipe

Claims (2)

[Claims] 1. An apparatus for measuring a lower flash point and an upper flash point of a mixed sample gas of an organic vapor, an inert gas and oxygen or air, and an explosion limit oxygen concentration, which has an explosive region of the mixed sample gas. Then, a closed container provided with means for detecting the pressure due to this explosion, a temperature measuring device for measuring the temperature of the explosion region, an ignition electrode arranged in the explosion region,
A heating device for heating the explosion zone to a predetermined temperature, one end of which is connected to the closed container and the other end of which is connected to a vacuum device, and an inert gas introducing valve and an oxygen or air introducing valve are respectively provided. An explosive limit region measuring device comprising: a gas introduction pipe which is interposed and which supplies an inert gas and oxygen or air to the explosive region. 2. A device for measuring a lower flash point and an upper flash point of a mixed sample gas of an organic vapor, an inert gas and oxygen or air, and an explosion limit oxygen concentration, which has an explosive region of the mixed sample gas. Then, due to this explosion, a hermetically sealed container detachably attached, a thermocouple for measuring the temperature in the explosive region, an ignition electrode arranged in the explosive region, and the hermetically sealed container being immersed thereinto An oil bath for heating the explosion zone to a predetermined temperature, one end of which is connected to the closed container, the other end of which is connected to a vacuum pump, and an inert gas introducing valve and an oxygen or air introducing valve are respectively interposed. Equipped,
A device for measuring an explosion limit area, comprising: a gas introduction pipe for introducing an inert gas and oxygen or air into the explosion area.