JP2002277454A - Burning velocity measuring device, method for measuring concentration of critical combustion supporting gas, and powder and granular matter handling method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a burning velocity measuring device for measuring the burning velocity of a sample under conditions in which the sample is actually handled, a method for measuring the concentration of combustion supporting gas capable of safely handling matter such as easily combustible matter, oxidants, etc., and a method for handling powder and granular matter based on the measuring method. SOLUTION: The burning velocity measuring device 1 provided with a sealed thermostatic chamber 2 housing the sample 4 inside, a gas supplying means 3 for supplying a predetermined concentration of an inert gas and the combustion supporting gas in the thermostatic chamber 2, an igniting means 5 for igniting the sample 4 in the thermostatic chamber 2, and a burning gas discharging means is used.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a combustion rate measuring device, a method for measuring a limit flammable gas concentration, and a method for handling powdery or particulate matter.

[Prior art]

[0002] Test methods for evaluating the dangers of handling substances include, for example, "Recommendations on the TRANSP".
ORT OF DANGEROUS GOODS-Manual of Tests and Criteri
a ", Second revised edition, UNITED NATIONS, includes the United Nations burning rate test and oxidizing substance test. The burning rate test is used to determine whether a sample falls under flammable substances. In the test, the oxidizing substance test measures whether a sample and a certain flammable substance have the power to increase the burning rate or the burning intensity of the flammable substance depending on the properties of the sample, These tests are used to determine whether a substance is applicable.These tests are similar to the EU test methods specified in the European Union (EU) Seventh Amendment Directive Guideline.

[0003] Normally, both the burning rate test and the oxidizing substance test are carried out in air at room temperature under atmospheric pressure. In the burn rate test, the flame of the gas burner, which is the ignition source, was brought into contact with one end of a long triangular prism-shaped sample.
The sample is ignited, and the time required for the sample to burn for a length of 100 mm (burning time) is measured. If the burning time is less than 45 seconds, it is determined that the sample is a flammable substance.

In the oxidizing substance test, a sample molded in a conical shape with a base diameter of 70 mm is placed on a nichrome wire as an ignition source, and a current is applied to the nichrome wire to measure the burning time of the sample. The combustion time is from the start of energization to the end of a main reaction such as generation of a flame, incandescence and increased combustion. As the sample, a reference mixture obtained by mixing a reference substance and a combustible substance at a predetermined mixing ratio, and a sample mixture obtained by mixing a sample and a combustible substance at a predetermined mixing ratio are used. The burning time is measured for both, and when the burning time of the sample mixture is shorter than the burning time of the reference mixture, it is determined that the sample mixture corresponds to the oxidizing substance.

[0005] The above burning rate test and oxidizing substance test are performed as follows.
Although it is used in various fields, it is actually used in an atmosphere (temperature, pressure, inert gas, etc.) different from the test conditions specified in these (tests are performed in air at room temperature under atmospheric pressure). Concentration and the concentration of the supporting gas, etc.), and in such a case, the above test method could not be applied. Further, there has been a need for a method for measuring the concentration of a supporting gas capable of safely handling substances such as easily combustible substances and oxidizing substances, and a method for handling powdery or granular substances based on the method.

[0006]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a combustion rate measuring device for measuring the burning rate of a sample under the condition where the sample is actually handled, and a method for measuring a substance such as a flammable substance or an oxidizing substance. It is an object of the present invention to provide a method for measuring the concentration of a supporting gas which can be safely handled, and a method for handling powdery or granular substances based on the method.

[0007]

According to the present invention, there is provided a combustion rate measuring apparatus comprising: a thermostat in which a sample is accommodated; and an inert gas and a supporting gas at a predetermined concentration in the thermostat. A gas supply unit for supplying the sample; an ignition unit for igniting the sample in the thermostat; and a unit for continuously discharging the combustion gas.

As described above, the combustion rate measuring device of the present invention
Since the burning rate test can be performed in an atmosphere controlled at an arbitrary temperature, pressure and gas concentration, the danger of the sample can be evaluated under the same conditions as the atmosphere in which the sample is actually handled. When the experiment is performed at a pressure higher than the atmospheric pressure, the evaluation can be performed by providing an adjusting valve in each of the gas supply unit and the combustion gas discharge unit.

In the method for measuring the concentration of the limiting flammable gas according to the present invention, the concentration of the limiting flammable gas at which the sample does not burn or the combustion does not continue is measured by using the above-mentioned combustion rate measuring device.

As described above, the combustion rate measuring device of the present invention
Since the concentrations of the inert gas and the flammable gas can be set arbitrarily, it is possible to find the limit flammable gas concentration of the sample by conducting the test in multiple The amount of inert gas replacement can be determined.

[0011] In the method for handling powdery or particulate matter according to the present invention, the concentration of flammable gas in a facility for handling powdery or particulate matter is controlled to a value not higher than the limit flammable gas concentration obtained by the above-mentioned measuring method. Is what you do.

As described above, based on the measurement result of the limit flammable gas concentration of the powdery or particulate matter obtained by the combustion rate measuring apparatus of the present invention, the flammability in the equipment for handling the powdery or particulate matter is measured. By controlling the gas concentration and keeping the flammable gas concentration equal to or lower than the limit flammable gas concentration at all times, powdery or granular substances can be handled safely.

[0013]

An embodiment of the present invention will be described below in detail with reference to the drawings. FIG. 1 shows a combustion rate measuring device 1 according to this embodiment. The combustion rate measuring apparatus 1 includes a thermostat 2, gas supply means 3 for supplying an inert gas and a supporting gas at a predetermined concentration into the thermostat 2, and a sample 4 in the thermostat 2. And ignition means 5 for igniting.

The thermostat 2 is a closed box,
Based on the detection result by the temperature sensor, the inside of the thermostat 2 can be controlled to an arbitrary temperature by a heater and a cooler that are electrically operated. (In the case of the thermostatic bath 2 of the present invention, the temperature can be raised to about 250 ° C.). Further, the inside of the constant temperature bath 2 can be controlled to an arbitrary pressure by appropriately adjusting the supply amount control valve 26 and the exhaust amount control valve 21.

In order to visually check the combustion state of the sample in the thermostat 2, it is preferable that a transparent window is provided on a side surface or a part of a ceiling of the thermostat 2. As another method for confirming the combustion state of the sample, a method of measuring the temperature of the sample or the temperature near the sample with a temperature sensor such as a thermocouple can also be used.

At the bottom of the thermostat 2, a heat insulating material 6 for placing the sample 4 is provided. The heat insulating material 6 is for preventing heat generated by the combustion of the sample 4 from being conducted to the floor of the thermostat 2, and is made of non-combustible material such as asbestos, foam glass, foam concrete, diatomaceous earth, calcium silicate, and the like. Inorganic thermal insulation can be used. An explosion-proof port 14 is provided in the upper part of the thermostat 2 as a safety device.

The gas supply means 3 includes a supporting gas supply pipe 19 for supplying a supporting gas, an inert gas supply pipe 20 for supplying an inert gas, and a supporting gas and an inert gas. Flow meter 10 and flow meter 1 for adjusting the flow rate
1. A mixed gas supply pipe 12 for introducing a mixed gas of a predetermined concentration of a combustible gas and an inert gas into the constant temperature bath 2 is provided. In addition, a bypass 25 for replacing the thermostatic chamber with an inert gas at an early stage is provided in parallel with the flow meter 11. Further, in order to measure the concentration of the supporting gas inside the thermostat 2,
The thermostatic chamber 2 is provided with a combustible gas concentration meter 15.

Air or oxygen is usually used as the supporting gas, but halogens such as chlorine and bromine, and nitrogen oxides such as nitrogen monoxide, nitrogen dioxide and nitrous oxide are also used. Can be. Examples of the inert gas include rare gases such as helium, neon, and argon, nitrogen, and carbon dioxide.

The ignition means 5 is for igniting the sample 4, and includes a heating wire 7 and a driving device 8 for driving the heating wire. The heating wire 7 has a large resistivity, a high melting point, is hardly oxidized, and has a small temperature coefficient, such as a metal wire such as a nichrome wire, a kanthal wire, or an advanced wire, carbon,
Those obtained by linearizing carbides such as silicon carbide can be used.

The driving device 8 is for remotely controlling the heating wire 7 from outside the constant temperature bath 2. As shown in FIG. 2 (an enlarged plan view showing the ignition means 5), the handle 22 rotates. The heating wire 7 passes through a plurality of gears 23 and a shaft 24.
And the heating wire 7 can be moved up and down. Therefore, the heating wire 7 before energization or heated to a predetermined temperature by energization can be brought into contact with the sample 4 at an appropriate position. The heating wire 7 is connected to a power supply by a wiring 9 (FIG. 1).

A power supply for supplying power to the gas supply means 3 and the heating wire 7 and a gas supply amount, a gas exhaust amount, a temperature, and the like are controlled in a box 16 (FIG. 1) on which the thermostat 2 is mounted. And a control unit are stored. The front plate of the box 16 is provided with a slide transformer 18 for adjusting the amount of power supply to the heating wire 7 and a power supply switch 17 thereof.

The shape of the sample used in the combustion test is not limited to the shape (triangular prism and cone) specified in the UN combustion test, oxidizing substance test, etc. Any shape can be used as long as it is large enough to be installed on the upper surface 6. As the sample 4, for example, a lump material, a powdery or granular material, or the like can be used. In addition, if the paste has a viscosity enough to maintain the shape, it is stretched on the heat insulating material 6 to form a string, and Alternatively, in the case of a paste having low viscosity, the test can be performed by placing the paste in a box-shaped container.

The burning rate measuring method using the burning rate measuring apparatus 1 of the present invention conforms to the burning rate test and the oxidizing substance test specified in the aforementioned “UN Combustion Test” and “EU Test Method”. In addition to the method described above, the sample shape, the temperature in the thermostat 2, the pressure, the concentration of the flammable gas, the concentration of the inert gas, and the like are set to arbitrary conditions, and the same conditions as those in the atmosphere when actually handled are used. You can also test. The following is an example of a method for measuring a burning rate based on the above-mentioned United Nations burning rate test.

<Method of Measuring Burning Rate> 1) A powder sample 4 is filled in a sample filling section 32 of a sample molding machine 31 shown in FIG. The hardness of the filling is such that the sample molding machine 31 is dropped three times from a height of 2 cm onto a hard plane. 2) Next, as shown in FIG. 4, the cooled plate-shaped heat insulating material 6 is placed on the sample molding device 31, and after it is inverted, the sample molding device 31 is removed and the molded sample shown in FIG. 33
Get. The molded sample 33 has a triangular cross section and a length of 250.
mm triangular prism. 3) A heat insulating material 6 on which a molded sample 33 is placed is placed at the bottom of the combustion rate measuring device 1 shown in FIG. Set to. 4) Connect the heating wire 7 of the ignition means 5 to the ignition portion 3 of the molded sample 33
4 (FIG. 5), and energization of the heating wire 7 is started. 5) In the case where the molded sample 33 is ignited, the time measurement is started at the time when the ignition is performed to the length of 80 mm from the ignition portion 34,
From there, the time until burning for a further 100 mm in length (hereinafter referred to as burning time) was measured, and the burning rate (mm /
s). If no ignition occurs or if combustion does not propagate even after ignition, the combustion speed is set to zero.

The critical combustible gas concentration of the present invention can be determined by the combustion velocity measuring method shown above as an example. In general, when the concentration of the supporting gas is reduced, the substance does not burn below a certain concentration (does not ignite), or the combustion does not continue (once ignites, the combustion does not propagate thereafter) . The concentration of the supporting gas at this time is defined as the limiting supporting gas concentration.

Therefore, the combustion speed measuring device 1 of the present invention
By changing a plurality of the supporting gas concentrations by using, and measuring the burning rate in each atmosphere, it is possible to find the supporting gas concentration at which the sample 4 does not burn or the burning does not continue. Also, if necessary, temperature, pressure,
The measurement can be performed by appropriately changing the type of the supporting gas, the type of the inert gas, and the like, whereby the influence of the temperature, the pressure, and the like on the combustion speed can be evaluated.

The method for handling the powdery or granular material of the present invention is based on the limit combustible gas concentration of the powdery or granular material under an arbitrary atmosphere obtained by the above-mentioned method, and is actually used in the facility. When handling powdery or granular substances, the concentration of the supporting gas in the handling atmosphere is always controlled to be lower than the limit supporting gas concentration. According to this handling method, powdery or granular substances can be handled safely.

As the ignition means 5, for example, a gas burner or the like can be used in addition to the heating wire 7 shown in the above-described embodiment.

[0029]

EXAMPLES Hereinafter, the present invention will be described in detail with reference to examples, but the present invention is not limited to the following examples.

EXAMPLE Using a combustion rate measuring device 1 as shown in FIG. 1, supply of air (using oxygen in air as a supporting gas) and nitrogen (using as an inert gas) by gas supply means 3. The burning rate of potassium tert-butoxide was measured at various ratios. The temperature in the thermostat 2 was controlled at 20 ° C., the pressure was controlled at 1 atm, and the concentration of oxygen gas, which was a supporting gas, was changed in the range of 21% to 12% as shown in Table 1, and under each condition. The burning rate was measured. Table 1 shows the results. From Table 1, if the supporting gas (oxygen gas) concentration is 18% or less, the combustion of potassium tert-butoxide is not continued,
You can see that it can be handled safely.

[0031]

[Table 1]

[0032]

According to the combustion rate measuring apparatus of the present invention, a sample is actually handled because a combustion rate test is performed at an arbitrary temperature, an arbitrary pressure, and an arbitrary concentration of a supporting gas in a closed thermostat. There is an effect that the danger of the sample can be evaluated under the same conditions as in the atmosphere.

In addition, since the concentration of the supporting gas can be set arbitrarily, the test is performed under various conditions of the supporting gas concentration, so that the sample does not burn or the combustion does not continue. There is an effect that can be found.

Furthermore, by setting the concentration of the supporting gas in the equipment for handling the sample to be equal to or less than the limiting concentration of the supporting gas based on the above-mentioned limiting concentration of the supporting gas, the sample can be handled safely. There is.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing a combustion rate measuring device according to the present invention.

FIG. 2 is an enlarged plan view showing an ignition means of the combustion rate measuring device according to the present invention.

FIG. 3 is an exploded explanatory view showing a sample molding method.

FIG. 4 is a sectional view showing a sample molding machine.

FIG. 5 is a perspective view showing a molded sample.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Combustion rate measuring device, 2 ... Constant temperature chamber, 3 ... Gas supply means, 4 ... Sample, 5 ... Ignition means, 6 ... Heat insulating material, 7 ... Heating wire, 8 ... Drive device, 9 ... Wiring, 10 ... Flow meter , 11: flow meter, 12: mixed gas supply pipe, 13: gas exhaust pipe, 14
... safety device, 15 ... combustible gas concentration meter, 16 ... box, 17 ... ignition switch, 18 ... slide transformer, 1
9 ... combustible gas supply pipe, 20 ... inert gas supply pipe, 21
... Displacement adjusting valve, 22 ... Handle, 23 ... Gear, 24 ...
Shaft, 25 ... Bypass, 26 ... Supply amount control valve

Claims (4)

[Claims] 1. A thermostat in which a sample is contained, a gas supply means for supplying an inert gas and a flammable gas at a predetermined concentration into the thermostat, and a sample in the thermostat. A combustion rate measuring device comprising an ignition means for igniting and a means for discharging combustion gas. 2. The combustion rate measuring device according to claim 1, wherein said sample is a powdery or granular substance. 3. A method for measuring a critical supporting gas concentration at which a sample does not burn or combustion does not continue using the burning rate measuring device according to claim 1 or 2. 4. A powdery substance characterized by controlling the concentration of a flammable gas in a facility for handling powdery or particulate matter to be below the limit flammable gas concentration obtained by the measuring method according to claim 3. Or how to handle particulate matter.