JPH0621848B2 - Falling dust measurement device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a falling dust measuring apparatus that collects falling dust and measures its weight.

(Prior Art) In recent years, air pollution due to dust has been increasing, and, for example, coal centers and coal-fired power plants have been constructed in various places with the expansion of use of coal energy, and pollution due to dust has become a problem. In addition, most of the raw materials such as coal and iron ore that are handled in steel mills are fine powders, and dust generated in various processes may scatter to pollute the environment. Such air pollution due to dust can be generally classified into suspended dust and fallen dust, and any amount of dust is widely used as an index of air pollution due to dust.

Conventionally, the standard measurement of fallen dust is usually carried out by collecting a sample for one month using a fallen dust collector, and showing the measurement result in units of t / Km ² / month.
A deposit gauge or a dust jar is generally used as the collector. Various types of deposit gauges have been used in the past, such as those proposed as a standard by ISO (International Organization for Standardization), British standards, or domestically produced ones ( (Refer to Pollution Measurement Technical Guide (Corona)). For special purposes, it is also practiced to collect and measure fallen dust in a Petri dish or aluminum foil for a short period (24 to 48 hours).

On the other hand, establishment of a method for predicting the amount of generated dust and the amount scattered to the surrounding environment is an important issue for environmental management. In order to establish this prediction method, it is indispensable to perform a quick response measurement. However, as described above, the conventional descent and dust measurement device usually requires a long collection period of about one month.
In order to measure the amount of soot and dust, it is necessary to perform a complicated manual analysis operation (see above). Therefore, it is impossible to perform the measurement quickly by using the conventional measuring device, and the amount of the generated dust and soot can be reduced. It is not possible to accurately predict the amount of scattering to the surrounding environment.

On the other hand, in order to perform a quick response dust measurement, a falling dust collection device using a hammer and a vibrator, which are well known in the field of powder transportation, has been proposed. That is, FIG. 7 shows this apparatus. In the figure, a is a stainless collecting funnel (diameter 240 mm) whose inner wall is mirror-finished, and b is attached to the lower conduit of this collecting funnel a. An electromagnetic vibrator that slightly vibrates the collecting funnel a in the state, c is provided above the upper end edge of the collecting funnel a, and is a hammering device for hammering by periodically supplying compressed air to the collecting funnel a. is there. The present collecting device prevents the dust that has fallen into the collecting funnel a from the opening of the collecting funnel a from being attached to the inner wall surface of the collecting funnel while preventing the dust from adhering to the inner wall surface by the operation of the vibrator b and the hammering device c. It is dropped on the medicine wrapping paper d which is arranged at, and the weight of the dust is weighed.

In powder hoppers, etc.,
Publication No. 52-66090, Japanese Utility Model Publication No. 36-
As disclosed in Japanese Patent No. 12336, in order to form a gas synovial film on the lower inclined surface of the hopper, there is a device in which a gas ejection port is simply arranged to prevent the powder from adhering to the inner wall surface of the hopper.

(Problems to be solved by the invention) However, when the collection efficiency of three types of test dust was examined using the former apparatus shown in FIG. 3, the Kanto Loam (8
The collection efficiency of the seeds is about 80-90%.
(Type 0) has a collection efficiency of 20 to 40%, and the collection efficiency of iron oxide (Fe ₂ O ₃ ) is 80 to 90%, showing considerable variations. Note that the collection efficiency is a comparison value M ₂ / M of the weight M _{1 of} dust that is naturally dropped from above the collecting funnel a and the weight M _{2 of} dust that reaches the medicine packing paper d below the collecting funnel a. _{Is 1} . Therefore, the apparatus having the configuration shown in FIG. 7 has a large variation in the collection efficiency depending on the quality of the powder, and therefore cannot accurately measure all kinds of fallen dust amount.

Even if the latter example of the powder hopper is applied to the falling dust collection funnel as it is, the amount of the dust once dropped inside the funnel is blown out from the upper opening to the outside of the funnel by the jet gas, and there is a large amount of dust. The collection efficiency is low and the amount of dust fall cannot be measured accurately.

The present invention has been made in view of the above circumstances, and is capable of collecting all kinds of fallen dust with high collection efficiency in a short time, and the collected fallen dust amount can be easily measured. Therefore, it is an object of the present invention to provide a measuring device capable of effective descent and dust measurement.

(Means for Solving the Problems) The present invention is provided with a collecting funnel, receives falling dust from the upper end opening of the collecting funnel, and introduces the falling dust into the collecting pipe at the bottom of the funnel to reduce the amount of falling dust. In the measuring device, a swirling downward airflow outlet having a tangential outflow direction is provided in the upper part of the collecting funnel, and a pressure feed pipe is connected to this outlet to clean air from the outlet to the inner wall of the funnel. Along the bottom of the collecting pipe, a downward spiral airflow can be formed, and a suction port for sucking substantially the entire amount of the downward spiral airflow is disposed at the outlet of the collecting pipe so as to face the suction pipe. A pressure-feeding pipe is connected through the pressure-feeding pipe, the pressure-feeding pipe is continuously connected to the spiral downward airflow outlet, and circulation supply is possible, and from the outlet of the collecting pipe to the suction port of the suction pipe, A filter that collects soot and dust挿出 entrant in providing,
The falling dust measuring apparatus is provided with a dust measuring apparatus for measuring the amount of dust collected in the filter.

(Operation) In the device of the present invention, a downward airflow is formed along the inner wall surface of the collecting funnel, and the downward airflow is sucked by the suction pipe in substantially the entire amount to be discharged to the outside air or recirculated for the downward airflow. This allows the descending airflow to function as a boundary layer between the inner wall of the collecting funnel and the falling dust without allowing the descending airflow to flow toward the upper opening side of the funnel, so that almost all of the falling dust that falls inside the funnel adheres to the inner wall of the collecting funnel. Without being put on the descending air flow, it is transferred into the collecting pipe at the bottom of the collecting funnel, and sucked and collected on the upper surface of the filter immediately before the outlet (lower end opening) of the collecting pipe.
Therefore, regardless of the type of dust, it is possible to directly collect the fallen dust on the filter with high collection efficiency. In addition, since the amount of soot and dust collected on the filter is measured directly on the spot by a measuring device, for example, a measuring device using the β-ray absorption method, the amount of soot and dust can be easily measured without a troublesome operation. Can measure quickly, accurately and accurately.

In the present invention, it is preferable to form a descending airflow over at least the inclined surface of the inner wall surface of the collecting funnel, that is, the entire surface of the surface where the dust and particles are in contact with the descending dust. Can be increased. Further, it is preferable that the descending airflow is formed by a clean gas containing no dust, so that only the falling dust can be collected in the filter and an accurate measurement can be performed.

(Example) An example of the present invention will be described with reference to Figs.

The falling dust measuring apparatus shown in FIG.
A measuring unit 2, a filter supply device 3, an air circulation supply device 4, a dust amount measuring device 5, and an automatic control device 6.

The collecting funnel 1 has a structure shown in FIGS. 2 (a) and 2 (b), and suction-moves the vortex-like downward airflow toward the collecting pipe 1c along the inner wall.

The measuring unit 2 includes a fixed unit 2a fixed to the collecting pipe 1c of the collecting funnel 1, an open / close unit 2b connected to the fixed unit 2a and holding the suction pipe 4a, and an open / close unit 2b.
Unit opening / closing motor 2d for moving the belt from / to the fixed unit 2a and opening / closing the band-shaped filter insertion passage 2c therebetween.
Consists of. To close the opening / closing unit 2b, the outlet of the collecting pipe 1c and the suction port of the suction pipe 4a are sealed and communicated with each other via the belt-shaped filter 3a.

The outlet (lower end opening) of the collecting pipe 1c is located in the central portion of the lower surface of the fixed unit 2a and is inclined to the central portion of the strip-shaped filter insertion passage 2c. The suction port (upper end opening portion) of the suction pipe 4a connected to the opening / closing unit 2b has an opening / closing unit 2b.
Is located in the center of the upper surface of the filter and is inclined toward the center of the filter insertion passage 2c, and is formed so as to be in sealed communication with the outlet of the collecting pipe 1c and the strip filter 3a of the strip filter insertion passage 2c, and to be detachable and releasable. .

The filter feeder 3 supplies a belt-shaped filter 3a between the outlet of the collecting pipe 1c and the suction port of the suction pipe 4a at the center of the filter insertion passage 2c. The rewinding reel 3b and the take-up reel of the belt-shaped filter 3a. 3c and tension reel 3
d, 3e, a reel drive motor 3f for the rewind reel 3b, and a reel drive motor 3g for the take-up reel 3c.

The air circulation supply device 4 comprises a suction pipe 4a, a suction pump 4b, and a pressure feed pipe 4c, and the pressure feed pipe 4c is connected to the spiral downward airflow outlet 29 from the tangential direction of the collection funnel 1. By the operation of the suction pump 4b, the air is fed by the pressure feed pipe 4c-
It flows through a circulation route of the spiral downward airflow outlet 29, the collecting pipe 1c, the belt-shaped filter 3a, the suction pipe 4a, and the suction pump 4b.

The dust amount measuring device 5 includes a β-ray source 5a adjacent to the lower end opening of the collecting pipe 1c at the center of the lower surface of the fixed unit 2a,
A β-ray transmission amount detector 5b adjacent to the upper end opening of the suction tube 4a at the center of the upper surface of the opening / closing unit 2b and opposed to the β-ray source 5a via the band-shaped filter 3a, and the β-ray source 5a and β-ray transmission amount. The detector 5b includes a measurement control unit 5c, a calculation unit 5d, and a recording display unit 5e, and measures the amount of falling dust collected by the belt-shaped filter 3a by the β ray absorption method.

The automatic control device 6 includes a lid opening / closing control unit 6 of the opening / closing motor 1f.
a, reel control unit 6 of reel drive motors 3f, 3g
b, pump control section 6c of suction pump 4b, unit opening / closing control section 6d of unit opening / closing motor 2d, measurement control section 5
c and a general control section 6e of each of these control sections. The lid opening / closing control unit 6a has a function to prevent rainwater from entering the collecting funnel 1 by automatically performing the emergency closing operation of the opening / closing lid 1e according to the rainfall detection signal from the rainfall sensor 7 in addition to the steady control.

Next, the automatic measurement of falling dust will be described in detail.

The opening / closing unit 2b is opened, and the band-shaped filter 3 is opened.
The new portion of a is supplied to just below the lower end opening of the collecting pipe 1c, and then the closing operation is performed to clamp the strip filter 3a.

The β-rays are transmitted to the new portion of the belt-shaped filter 3a, the β-ray transmission amount is counted by the calculation unit 5d for a certain period of time, stored and held, and the preparation operation is completed.

The opening / closing lid 1e is opened, and when the opening / closing lid 1e is completed, the suction pump 4b is operated to allow air to flow through the circulation route.

As a result, the falling dust that has settled from the upper opening of the collecting funnel 1 is made to flow down into the collecting pipe 1c without being blown up and adhering to the inner wall surface of the collecting funnel 1,
The whole amount can be collected at the new part of the belt-shaped filter 3a. Further, since the air that has passed through the new portion of the belt-shaped filter 3a is sucked into the suction pipe 4a in a clean state, clean air always flows out from the spiral downward airflow outlet 29 to prevent the clogging thereof, and the funnel 1 A uniform spiral downward airflow film is formed without polluting the inclined inner wall surface, and only the falling dust is sent by air to a new portion of the belt-shaped filter 3a and collected.

The suction pump 4b is operated for 55 minutes and stopped, and at the same time, the opening / closing lid 1e is returned to the original closed position.

Next, in the device 5 for measuring the amount of soot and dust, the β-ray source 5 is provided at the dust and soot portion collected in the new portion of the belt-shaped filter 3a.
Irradiation of β-rays from a and the transmission amount of the β-rays is detected by the β-ray transmission amount detector
Counting for a certain period of time by b, and calculating and calculating the adhesion drop dust amount on the filter from the relational expression determined by the logarithmic ratio of the count value and the count value stored by the calculation unit 5d and the mass absorption coefficient of β ray Then, it is output to the record display section 5e and is recorded and displayed.

By repeating the above measurement operation at regular intervals, it is possible to accurately measure the change over time or the cumulative value of the amount of fallen dust for one day or one month.

Further, since the apparatus of this example circulates and uses the air that does not contain the falling dust that is sucked from the collection funnel 1 through the band-shaped filter 3a as the air for forming the descending airflow as described above, it is collected in the band-shaped filter 3a. The soot and dust are only the soot and dust that drops to the opening of the collection funnel 1, and therefore only the fallen and soot can be collected and the amount of dust and soot can be accurately measured.

In this case, what should be noted in the apparatus of this example is that the flow rate of the suction pump 4b is not involved in the measurement and calculation of the amount of fallen dust. That is, the swirling clean air blown out from the swirling downward airflow outlet 29 along the inner wall of the collecting funnel 1 has a function of reliably filtering and collecting the falling dust to the belt-shaped filter 3a without losing the function as a boundary layer. Is playing. In the case of the device of this example, the collection funnel 1 has a diameter of 200 mm, and the suction flow rate of the suction pump 4b is several tens / minute, but the spiral downdraft forming mechanism and the band-shaped filter 3a are used.
The suction flow rate of the suction pump 4b to be used is determined by the ventilation resistance. Therefore, when the ventilation resistance of the belt-shaped filter 3a rises to a certain value or more due to the fallen dust collection in the suction trapping concentration, the integrated control unit 6e moves the belt-shaped filter 3a and starts the trapping with a new belt-shaped filter. By doing so, the function of forming the boundary layer by the descending airflow can be favorably maintained. At this time, a semiconductor pressure sensor (not shown) is used to detect the ventilation resistance of the belt-shaped filter.

As described above, the apparatus of this example realizes the rapid and accurate measurement of the weight concentration of the falling dust collected at the bottom of the collection funnel 1 at that position. In this case, the amount of dust fall in recent urban areas is several t / Km ² / month or more,
When the measurement at this concentration level is carried out for 1 hour by the present apparatus, a measured value of about 100 μg / hr (however, collected at a diameter of φ200) is obtained. This value is in a region where the stability of the zero point of the β-ray absorption detection value ± 5 μg / hr can be measured with sufficient accuracy, and the effectiveness of the device of the present invention is recognized.

In the present invention, the configuration of the descending airflow forming mechanism that forms a spiral descending airflow toward the bottom of the funnel along the inner wall of the collecting funnel is as shown in FIGS. 2 (a) and 2 (b). 1 is provided with a spiral downward airflow outlet 29 in which the outflow direction is a tangential direction, and the pressure feed pipe 4 is provided at this outlet 29.
Connect c to collect clean air from the outlet 29. Funnel 1
The simplest structure is to make it spiral down along the inner wall, and moreover, it is possible to carry it down and carry it all into the collecting pipe while surely preventing the dust and dust from adhering to the inner wall of the funnel.

(Effects of the Invention) As described above, according to the apparatus for measuring fallen dust of the present invention, it is possible to collect fallen dust with high collection efficiency and easily measure the amount of this collected dust in a short time. Therefore, it is possible to carry out a quick response descent and dust measurement. Therefore, the device of the present invention is effectively used for establishing a method for predicting the amount of dust and dust generated and the amount of scattered dust to the surrounding environment, and greatly contributes to proper environmental management.

[Brief description of drawings]

FIG. 1 is a schematic view showing an apparatus for automatically measuring falling dust and dust according to an embodiment of the present invention, FIGS. 2 (a) and 2 (b) are schematic views showing the spiral downdraft formation mechanism of FIG. 1, and FIG. FIG. 6 is a schematic view showing an example of a conventional descent dust collection mechanism. 1 ... Collection funnel, 1c ... Collecting pipe, 1d ... Wire mesh, 1
e ... Open / close lid, 1f ... Open / close motor, 2 ... Measurement unit, 2a ... Fixed unit, 2b ... Open / close unit,
2c ... Belt-shaped filter insertion passage, 2d ... Unit opening / closing motor, 3 ... Filter feeding device, 3a ... Band-shaped filter, 3b ... Rewind reel, 3c ... Take-up reel, 3d, 3e ... Tension Reel, 3f, 3g ...
Reel drive motor, 4 ... Air circulation supply device, 4a ...
... Suction pipe, 4b ... Suction pump, 4c ... Pressure feed pipe, 5 ...
… Dust amount measuring device, 5a …… β-ray source, 5b …… β
Line transmission amount detector, 5c ... Measurement control unit, 5d ... Calculation unit, 5e ... Record display unit, 6 ... Automatic control device, 6a ...
... Lid opening / closing control section, 6b ... Reel control section, 6c ... Pump control section, 6d ... Unit opening / closing control section, 6e ... Overall control section, 7 ... Rainfall sensor, 29 ... Whirlpool downward airflow outlet .

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-58-220020 (JP, A) Actual opening S57-156844 (JP, U) Actual opening S61-46442 (JP, U) Actual opening 40- 18830 (JP, Y1)

Claims (1)

[Claims] 1. An apparatus comprising a collecting funnel, which receives falling dust from the upper end opening of the collecting funnel and introduces the falling dust into a collecting pipe at the bottom of the funnel to measure the amount of falling dust. A swirling downward airflow outlet with a tangential direction to the outflow direction is provided in the upper part of the inside, and a pumping pipe is connected to this outlet, and clean air from the outlet is swirling downward toward the bottom collecting pipe along the inner wall of the funnel. In addition to enabling air flow formation, a suction pipe is arranged at the outlet of the collecting pipe so as to face a suction port for sucking substantially all of the spiral downward flow, and a suction pipe is connected to the suction pipe via a pump, A pumping pipe is continuously connected to the spiral downward airflow outlet to enable circulation supply, and a filter for collecting dust from the outlet of the collecting pipe is inserted between the outlet of the collecting pipe and the suction port of the suction pipe. Provided for access
A falling dust measuring apparatus comprising a dust measuring apparatus for measuring the amount of dust collected in the filter.