JP6276059B2 - Smoke collector - Google Patents

Description

  The present invention relates to a smoke collector. For example, the present invention relates to a smoke collecting device used in a combustion measuring device that measures a heat generation rate of a measurement target.

  Conventionally, the fire resistance performance verification method of the Ministry of Construction Notification No. 1433 of 2000 was known as a fire resistance performance verification method (hereinafter referred to as “notification verification method”) (see Non-Patent Document 1). In this notification verification method, first, a target room (single room or multiple rooms assuming simultaneous combustion) is set, and the duration of a fire occurring indoors is calculated. After that, for the main structural parts facing the target room, the limit time that can maintain the fire resistance required for each main structural part (non-damage, heat insulation, flame resistance), that is, the possessed fire resistance time for each member Calculate. And if the possessed fireproof time of the main structural part is equal to or longer than the fire duration time, it is determined that the performance is satisfied. This verification is performed for all the main structural parts constituting the building.

Of these, the rate of heat generation is used in the formula for calculating the retained fire resistance time. The heat generation rate is the amount of heat generated per unit time.
As a method for measuring the heat generation rate, for example, there is an oxygen consumption method. The oxygen consumption method is a method of actually burning a measurement object, measuring the flow rate of smoke generated and the oxygen concentration, and calculating the heat generation rate based on the measured values of the flow rate and oxygen concentration.

In order to measure the heat generation rate by the above oxygen consumption method, the following combustion measuring device is used.
In other words, the combustion measuring device includes a box-shaped hood having a lower surface opened and a suction port formed on the upper surface, a support column that supports the hood, and a smoke exhaust duct that sucks and discharges air inside the hood from the suction port. And a sensor unit that is provided in the smoke exhaust duct and measures the air flow rate and the oxygen concentration.

  Place the measurement object under the hood, burn this measurement object, suck the generated smoke into the exhaust duct, and the smoke flow rate and oxygen concentration, carbon dioxide concentration, and carbon monoxide concentration in the exhaust duct Gas concentration is measured. Then, the heat generation rate is calculated based on the measured values of the flow rate and the gas concentration.

Explanation of 2001 fire resistance verification method and calculation examples and explanations, Ministry of Land, Infrastructure, Transport and Tourism Housing Bureau Building Guidance Division

By the way, the measurement object for measuring the heat generation rate may be relatively small with respect to the size of the hood of the above-described combustion measuring device.
In this case, since the distance from the burning measurement object to the suction port of the hood becomes long, a large amount of ambient air is entrained as the smoke rises, and the generated smoke reaches the suction port. The smoke concentration is diluted excessively. As a result, there is a problem that the difference between the gas concentration of smoke and the gas concentration of fresh air becomes too small and the measurement accuracy decreases.

  In order to solve this problem, a hood may be newly installed or modified in accordance with the magnitude of combustion to be measured, but there is a problem that costs increase.

  An object of this invention is to provide the smoke collector which can measure a small heat generation rate with high precision, even if it uses the existing large sized combustion measuring apparatus.

  The smoke collecting device (for example, a smoke collecting device 2 described later) according to claim 1 has a lower surface (for example, a lower surface 10A described later) opened and a suction port (for example, a suction port 12 described later) formed on the upper surface. A box-shaped hood (e.g., a hood 10 described later), a column (e.g., a column 90 described later) that supports the hood, and a duct (e.g., a vacuum that sucks and discharges air inside the hood from the suction port). A smoke exhaust duct 20 described later, and a sensor unit (for example, a duct sensor unit described later) that is provided in the duct and measures the air flow rate and gas concentration (for example, oxygen concentration, carbon dioxide concentration, and carbon monoxide concentration). 30), and a cylinder portion (for example, a cylinder portion 40 described later) provided in the hood and extending in the vertical direction. Be

According to this invention, the smoke collecting device is provided inside the hood of the combustion measuring device, and the measurement object is burned directly under the smoke collecting device. Then, the smoke due to this combustion is sucked into the duct of the combustion measuring device through the cylinder portion of the smoke collecting device.
Therefore, by providing the smoke collecting device, the distance from the burning portion of the measurement object to the suction port is substantially shortened, so that the ambient air entrained as the smoke rises is reduced, and the conventional Thus, it is possible to prevent the smoke concentration from being excessively diluted until the generated smoke reaches the suction port. Therefore, even if an existing large-sized combustion measuring device is used, a small heat generation rate can be measured with high accuracy.

  Moreover, since it is only necessary to arrange the smoke collector of the present invention inside the hood of the existing combustion measuring device, it is not necessary to modify the existing combustion measuring device at all, and it is easy to install and remove, Low cost.

The smoke collecting apparatus according to claim 1 is characterized in that a gap (for example, a gap d described later) is formed between the suction port of the hood and the upper end surface of the cylindrical portion.

  When the measurement target for measuring the heat generation rate is relatively small with respect to the size of the hood of the combustion measuring device, the amount of air sucked by the smoke exhaust duct is excessive with respect to the amount of smoke generated from the measurement target. As a result, since the inflow amount of ambient air other than smoke into the smoke collector increases, the smoke is excessively diluted, and the heat generation rate may not be accurately measured.

  However, according to the present invention, a gap is provided between the hood of the combustion measuring device and the cylinder portion of the smoke collecting device of the present invention so as not to be in direct contact. By providing such a gap, air in the vicinity of this gap is appropriately sucked into the smoke exhaust duct in addition to the gas passing through the smoke collector through this gap, so the amount of air flowing through the inside of the smoke collector is increased. The heat generation rate can be accurately measured without being excessive.

  In addition, since a gap is provided between the hood of the combustion measuring device and the cylinder portion of the smoke collecting device of the present invention so as not to come into direct contact, a damper is provided on the existing hood, the shape is changed, etc. It is economical without the need to modify the existing hood itself.

The smoke collection device according to claim 2 is a vane (for example, a vane 60 described later) provided on a lower end side of the cylindrical portion, and a driving device (for example, a driving device 70 described later) for rotating the vane. Are further provided.

  When a sensor is provided inside the cylinder part of the smoke collector, the smoke sucked from the lower end of the cylinder part may not be sufficiently mixed with air until it reaches the sensor of the smoke collector. Then, since the gas concentration of smoke is not uniform, there is a problem that the measurement accuracy of the sensor is lowered.

  However, according to the present invention, the sucked smoke and the surrounding air are agitated by driving the driving device and rotating the vane. Therefore, the smoke and the surrounding air are sufficiently mixed until the smoke reaches the sensor of the smoke collecting device. To obtain a uniform concentration. Therefore, smoke measurement accuracy can be increased.

  According to the present invention, the smoke collecting device is provided inside the hood of the combustion measuring device, and the measurement object is burned directly under the smoke collecting device. Then, the smoke due to this combustion is sucked into the duct of the combustion measuring device through the cylinder portion of the smoke collecting device. Therefore, by providing the smoke collecting device, the distance from the burning portion of the measurement object to the suction port is substantially shortened, so that the ambient air entrained as the smoke rises is reduced, and the conventional Thus, it is possible to prevent the smoke concentration from being excessively diluted until the generated smoke reaches the suction port. Therefore, even if an existing large-sized combustion measuring device is used, a small heat generation rate can be measured with high accuracy. Moreover, since it is only necessary to arrange the smoke collector of the present invention inside the hood of the existing combustion measuring device, it is not necessary to modify the existing combustion measuring device at all, and it is easy to install and remove, Low cost.

It is the top view and longitudinal cross-sectional view of the combustion measuring apparatus with which the smoke collector which concerns on one Embodiment of this invention was attached. It is a schematic diagram which shows the structure of the combustion measuring apparatus which concerns on the Example of this invention. It is a figure which shows the relationship between the passage air volume and elapsed time of a smoke collector and a smoke exhaust duct. It is a figure which shows the relationship between the fall amount of the oxygen concentration from ambient air of a smoke collector and a smoke exhaust duct, and elapsed time.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a plan view and a longitudinal sectional view of a combustion measuring device 1 to which a smoke collecting device 2 according to an embodiment of the present invention is attached.
The combustion measuring device 1 measures the heat generation rate of a combustible material that is a measurement target. The combustion measuring apparatus 1 includes a hood 10, four support columns 90 that support the hood 10, a smoke exhaust duct 20 connected to an upper end surface of the hood 10, and a duct sensor provided in the smoke exhaust duct 20. Unit 30.

The hood 10 has a box shape, and the lower surface 10A of the hood 10 is open. On the other hand, the upper portion of the hood 10 has a quadrangular pyramid shape composed of four gradient surfaces 11, and a suction port 12 is formed at a portion corresponding to the apex of the quadrangular pyramid.
The four columns 90 support the four corners of the hood 10 in plan view.

  The smoke exhaust duct 20 is connected to the suction port 12 of the hood 10. A fan (not shown) is provided at the connection destination of the smoke exhaust duct 20. By driving the fan, the air inside the hood 10 is sucked into the smoke exhaust duct 20 from the suction port 12 and discharged. The

The duct sensor unit 30 measures the flow rate of air flowing inside the smoke exhaust duct 20 and gas concentrations such as oxygen concentration, carbon dioxide concentration, and carbon monoxide concentration. The duct sensor unit 30 includes an air volume sensor unit 31 that measures the air volume in the smoke exhaust duct 20, a thermocouple 32 that measures the temperature in the smoke exhaust duct 20, and a sample gas that collects air in the smoke exhaust duct 20. A collection tube 33.
The sample gas sampling tube 33 is connected to a gas analyzer 34 that measures the oxygen concentration.

  The smoke collector 2 is provided inside the hood 10. Specifically, the smoke collector 2 includes a cylindrical portion 40 extending in the vertical direction, a smoke collector sensor portion 50 provided in the cylindrical portion 40, and a vane 60 provided on the lower end side of the cylindrical portion 40. And a driving device 70 that rotationally drives the vane 60.

  The upper end surface of the cylinder part 40 faces the suction port 12. A flange 41 extending substantially horizontally toward the outside is formed at the upper end edge of the cylindrical portion 40, and a gap d is formed between the outer end edge of the flange 41 and the gradient surface 11. .

  The lower end side of the cylindrical portion 40 is a quadrangular pyramid-shaped chamber 42 that expands downward. The lower end side of the chamber 42 is partitioned by a partition plate 43 extending in the horizontal direction, and an opening 44 is formed in the partition plate.

  The smoke collector sensor unit 50 measures the flow rate of air flowing inside the cylinder unit 40 and gas concentrations such as oxygen concentration, carbon dioxide concentration, and carbon monoxide concentration. The smoke collector sensor unit 50 includes an air volume sensor unit 51 that measures the air volume in the cylinder unit 40, a thermocouple 52 that measures the temperature in the cylinder unit 40, and a sample gas sampling that samples the air in the cylinder unit 40. A tube 53.

A switching valve 54 is provided in the middle of the sample gas sampling pipe 33 of the smoke exhaust duct 20, and the sample gas sampling pipe 53 of the smoke collector sensor unit 50 is connected to the switching valve 54.
By switching this switching valve 54, the gas analyzer 34 can selectively measure the gas concentration inside the sample gas sampling tube 33 or the gas concentration inside the sample gas sampling tube 53.

The vane 60 is disposed inside the chamber 42 and immediately above the opening 44 of the partition plate 43.
The driving device 70 includes a rotating shaft 71 connected to the vane 60 and extending downward through the opening 44 of the partition plate 43, and a motor 72 that rotationally drives the rotating shaft 71. According to this driving device 70, the vane 60 rotates through the rotating shaft 71 by driving the motor 72.

[Example]
Using the above-described combustion measuring apparatus 1, a combustion experiment was performed under the following experimental conditions.
FIG. 2 is a schematic diagram showing the configuration of the combustion measuring apparatus 1 according to the embodiment of the present invention.
The smoke collecting device 2 described above was set inside the hood 10 of the combustion measuring device 1 described above, and a box-shaped fire chamber model 80 imitating a fire chamber was further set. An opening 81 is provided on the side surface of the fire chamber model 80, and the opening 81 is disposed at the lower end of the smoke collector 2.
In addition, a burner 82 using propane gas as a fuel was placed inside the fire chamber model 80 as a measurement target.

Specific experimental conditions are as follows.
The amount of propane gas supplied from the burner was constant at 10.6 l / min. Further, the duct diameter of the smoke collector 2 is 200 mm, the size of the flange 41 is 0.93 m × 0.93 m, and the width dimension of the gap d between the flange 41 and the hood 10 is approximately 6 to 8 cm.

  The burner 82 was burned inside the fire chamber model 80. In addition, the fan (not shown) to which the smoke exhaust duct 20 is connected was driven, and the driving device 70 was driven to rotate the vane 60.

Then, the smoke due to the combustion of the burner 82 flows out from the fire chamber model 80 through the opening 81 to the outside. Since the fan of the smoke exhaust duct 20 is driven to rotate, the smoke that has flowed out is sucked into the chamber 42 of the cylindrical portion 40 through the opening 44 of the smoke collector 2. At this time, the rotation of the vane 60 mixes smoke and ambient air.
The smoke flowing into the chamber 42 passes through the smoke collector sensor unit 50 and flows out from the upper surface of the cylinder unit 40. Thereafter, the smoke is sucked into the smoke exhaust duct 20 through the suction port 12 together with the ambient air flowing through the gap d, and is exhausted through the duct sensor unit 30.

At this time, the passing air volume and the gas concentration are measured in each of the smoke collecting device sensor unit 50 and the duct sensor unit 30.
Specifically, the oxygen concentration in the sample gas collection pipe 53, that is, the cylinder part 40 of the smoke collector 2 was measured by the gas analyzer 34 until 160 S was reached after the start of the experiment. Then, the switching valve 54 was switched to 160S, and after 160S, the gas analyzer 34 measured the oxygen concentration in the sample gas sampling tube 33, that is, the flue gas duct 20 of the combustion measuring device 1.

The experimental results are shown in FIGS.
FIG. 3 is a diagram showing the relationship between the passing air volume of the smoke collector 2 and the smoke exhaust duct 20 and the elapsed time.
As shown in FIG. 3, the amount of air passing through the smoke collector was about 6.4% of the amount of air passing through the smoke exhaust duct. As a result, air around the smoke collector 2 that is not the measurement target is appropriately sucked into the smoke exhaust duct 20 through the gap d, and the amount of air flowing through the smoke collector 2 is compared with the amount of air flowing through the smoke exhaust duct. It can be seen that it can be sufficiently reduced.

FIG. 4 is a diagram showing the relationship between the amount of decrease in oxygen concentration from the ambient air around the smoke collector 2 and the smoke exhaust duct 20 and the elapsed time.
That is, the vertical axis in FIG. 4 is a value obtained by measuring the oxygen concentration of the smoke collector and the smoke exhaust duct and subtracting this measured value from the oxygen concentration of the ambient air.

  As shown in FIG. 4, the amount of decrease in the oxygen concentration of the smoke collector is 15.6 times the amount of decrease in the oxygen concentration of the existing hood. Therefore, it can be seen that the smoke collecting device 2 can reduce the ambient air entrained as the smoke rises and prevent the smoke concentration from being excessively diluted.

According to this embodiment, there are the following effects.
(1) Since the distance from the measurement object to the suction port 12 is substantially shortened by providing the smoke collecting device 2, the ambient air entrained as the smoke rises is reduced and generated as before. It is possible to prevent the smoke concentration from being excessively diluted before the smoke reaches the suction port 12. Therefore, even if the existing large combustion measuring device 1 is used, a small heat generation rate can be measured with high accuracy.

  Moreover, since it is only necessary to arrange the smoke collecting device 2 inside the hood 10 of the existing combustion measuring device 1, it is not necessary to modify the existing combustion measuring device 1 at all, and it is easy to attach and remove. , Low cost.

  (2) A gap d is provided between the hood 10 of the combustion measuring device 1 and the cylindrical portion 40 of the smoke collecting device 2 so as not to come into direct contact. By providing the gap d in this way, air around the smoke collector 2 that is not the measurement target is appropriately sucked into the smoke exhaust duct 20 through the gap d, so that the amount of air flowing through the smoke collector 2 is increased. The heat generation rate can be accurately measured without being excessive.

  In addition, since a gap d is provided between the hood 10 of the combustion measuring device 1 and the cylindrical portion 40 of the smoke collecting device 2 so as not to be in direct contact, a damper is provided on the existing hood 10 or the shape is changed. It is economical because there is no need to modify the existing hood 10 itself.

  (3) Since the sucked smoke and the surrounding air are agitated by driving the drive device 70 and rotating the vane 60, the smoke reaches the smoke collector sensor section 50 of the smoke collector 2. Thoroughly mixed with air to obtain a uniform concentration. Therefore, smoke measurement accuracy can be increased.

  It should be noted that the present invention is not limited to the above-described embodiment, and modifications, improvements, etc. within a scope that can achieve the object of the present invention are included in the present invention.

d ... Gap 1 ... Combustion measuring device 2 ... Smoke collector 10 ... Hood 10A ... Bottom surface 11 ... Gradient surface 12 ... Suction port 20 ... Smoke duct 30 ... Duct sensor part 31 ... Air volume sensor part 32 ... Thermocouple 33 ... Sample gas Sampling pipe 34 ... Gas analyzer 40 ... Cylinder part 41 ... Flange 42 ... Chamber 43 ... Partition plate 44 ... Opening 50 ... Smoke collector sensor part 51 ... Air volume sensor part 52 ... Thermocouple 53 ... Sample gas sampling pipe 54 ... Switching valve 60 ... Vane 70 ... Drive device 71 ... Rotating shaft 72 ... Motor 80 ... Fire chamber model 81 ... Opening 82 ... Burner 90 ... Still

Claims (2)

A box-shaped hood having a lower surface opened and a suction port formed on the upper surface, a support column that supports the hood, a duct that sucks and discharges air inside the hood from the suction port, and the duct. And a measurement unit that measures the air flow rate and oxygen concentration,
A cylindrical portion provided on the floor surface inside the hood and extending upward ;
A smoke collecting device , wherein a gap is formed between the suction port of the hood and the upper end surface of the cylindrical portion . A vane provided on a lower end side of the cylindrical portion;
The smoke collecting apparatus according to claim 1 , further comprising a drive device that rotationally drives the vane.

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