JPH1043542A - Method for purifying polluted air - Google Patents

Abstract

PROBLEM TO BE SOLVED: To automatically adjust a soil layer so as to contain always an adequate amt. of moisture. SOLUTION: Polluted air is supplied by a blower 8 into the soil layer 6 in a vessel 4. This polluted air passes the inside of the soil layer 6. The polluted air is purified by the effect of the microorganisms, etc., included in the soil layer 6. A pressure gage 10 measures the static pressure in a lower space part 20 in the lower part of the vessel 4 and a controller 14 judges the amt. of the moisture contained in the soil layer 6 from the measurement result. This controller opens solenoid valves 36, 42 to supply the water to the soil layer 6 from shower nozzles 34 and water feed pipes 40 when the controller judges that the static pressure is low and the amt. of the moisture is low. As a result, the moisture of the adequate amt. is always included in the soil layer 6 and the air purification effect possessed by the microorganisms and the soil is efficiently exhibited.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for purifying air contaminated with exhaust gas emitted from automobiles and factories, and more particularly to a method for purifying air contaminated by passing microorganisms through a soil layer in which microorganisms can grow. It relates to a method of purification.

[0002]

2. Description of the Related Art As a device for purifying air contaminated with exhaust gas discharged from automobiles and factories, the present applicant has proposed various types using soil from the viewpoint of protection of the global environment. . Such an air purification device using soil includes a soil layer in which microorganisms can propagate and air can flow, and an air flow unit that allows contaminated air to pass through the soil layer. Then, the contaminated air is passed through the soil layer by the air flow means, the harmful substances are attached to the soil particles, and the harmful substances are absorbed by microorganisms, thereby purifying the contaminated air.

On the other hand, in order to activate the function of soil particles to adhere harmful substances and the function of microorganisms to absorb harmful substances, that is, to activate the air purification action of the soil layer, It is desirable to maintain the moisture content of the constituent soil at or above a predetermined value.

[0004]

Therefore, it is necessary to monitor the degree of dryness of the soil layer and to replenish water as necessary. Particularly, it is necessary to automatically replenish such water.
It is desirable in terms of labor saving. Monitoring of the dryness of the soil layer can be performed by measuring the amount of water contained in the soil layer, and specifically, a pF meter may be used.

However, since the amount of water contained in the soil layer needs to be checked for the entire soil layer, if a pF meter is used, pF meters must be arranged at various places in the soil layer, and a large number of pF meters must be arranged. A total is required. As a result, the device becomes large-scale and the cost increases. Furthermore, the pF meter has the disadvantage of being fragile, and in principle requires water to be retained in the pF meter for the measurement, so that the water lost due to evaporation is periodically replenished. Maintenance is required.

Accordingly, an object of the present invention is to monitor the dryness of a soil layer without using a pF meter in purifying contaminated air using soil in which microorganisms have been propagated, so that the soil layer always contains an appropriate amount of moisture. It is an object of the present invention to provide a method for purifying contaminated air, which can automatically adjust the air concentration to efficiently exert the air purification action of microorganisms and soil.

[0007]

In order to achieve the above object, the present invention provides a method for purifying contaminated air by pumping and passing the contaminated air through a soil layer in which microorganisms can propagate and air can flow. The method of purifying contaminated air according to claim 1, wherein a pressure of the contaminated air to be pumped to the soil layer is measured, and water is supplied to the soil layer based on the measured pressure of the contaminated air.

The present invention also relates to a method of purifying contaminated air by purifying the contaminated air by suctioning the contaminated air through a soil layer in which microorganisms can propagate and air can flow. Measure the pressure of
Water is supplied to the soil layer based on the measured air pressure.

Further, the present invention is characterized in that the soil layer is formed in a container, and the pressure is measured in the container. Further, the present invention is characterized in that the pressure is a static pressure of the contaminated air or the sucked air.

[0010] The present invention also relates to a method for purifying contaminated air by purifying the contaminated air by passing the contaminated air through a soil layer in which microorganisms can propagate and air can flow.
An inverter supplies current to operate the blower, pumps the contaminated air to the soil layer, measures the frequency of the current supplied to the blower by the inverter, and supplies the soil layer based on the measured frequency. It is characterized by rehydration.

[0011] The present invention also provides a method for purifying contaminated air, which comprises purifying the contaminated air by passing the contaminated air through a soil layer in which microorganisms can propagate and air can flow.
Supplying a current by an inverter to operate the blower, sucking the contaminated air through the soil layer, measuring a frequency of the current supplied by the inverter to the blower,
Water is supplied to the soil layer based on the measured frequency.

Further, the present invention is characterized in that water is supplied to the soil layer by spraying water on the surface of the soil layer. Further, the present invention is characterized in that water is supplied to the soil layer through a pipe buried in the soil layer, and water is supplied to the soil layer. Further, the present invention is characterized in that water is atomized and mixed with the contaminated air to be pumped to the soil layer to supply water to the soil layer.

The pressure of the contaminated air pumped into the soil layer or the pressure of the contaminated air sucked through the soil layer is an indicator of the dryness of the soil layer. That is, in the former case, the lower the amount of moisture contained in the soil layer, the lower the pressure,
In the latter case, the lower the amount of water contained in the soil layer, the higher the pressure. Therefore, by supplying water to the soil layer based on these pressures of the contaminated air, the amount of water contained in the soil layer can always be kept at an appropriate value.

When contaminated air is pumped into the soil layer or pressure is sucked through the soil layer, the frequency of the current supplied from the inverter to the blower for that purpose is an indicator of the dryness of the soil layer. That is, in any case, the smaller the amount of water contained in the soil layer, the lighter the load on the blower becomes, and the lower the frequency becomes. Therefore, by supplying water to the soil layer based on the frequency of the inverter output current, the amount of water contained in the soil layer can always be kept at an appropriate value.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic explanatory view showing an air purification device for carrying out the method for purifying contaminated air of the present invention. The air purification device 2 includes a container 4, a soil layer 6, a blower 8, a pressure gauge 10, a water supply device 12, a control device 14, and the like, and is installed, for example, at a location close to a road with a large traffic volume. The shape of the container 4 is substantially a rectangular parallelepiped. A floor 16 of a soil layer formed of a mesh-like member such as a wire mesh is disposed at a position near the lower portion in the container 4, and a soil layer 6 is provided thereon. The soil layer 6 is soil in which microorganisms can propagate. In the embodiment, the soil layer 6 is composed of a mixture of ando, mulch, and perlite in a volume ratio of 3: 1: 1 to increase the porosity so that air can flow. The thickness of the soil layer 6 is 40 cm in this embodiment. Plants 18 are planted in the upper part of the soil layer 6, while a lower space 20 is formed between the bottom of the container 4 and the floor 16.

The blower 8 is arranged in the vicinity of the container 4, and its discharge port 22 is connected through a pipe 26 to an opening 24 formed in the lower space 20 on the side surface of the container.
The end of a tube 30 is connected to the suction port 28 of the blower 8,
Contaminated air is sucked in from the other end of the tube 30.

At the bottom of the container 4, a tube 32 communicating with the lower space 20 is attached at one end, and the pressure gauge 10 is connected to the other end of the tube 32.

Above the container 4, a plurality of shower nozzles 34 constituting the water supply device 12 are disposed with their jet ports facing downward.
Is connected to a water supply facility (not shown) through a water supply pipe 38 to which is attached. On the other hand, the water supply device 12
The water supply pipe 40 in which a number of holes are formed constitutes the container 4
The solenoid valve 42 is attached on the way, and the end of the end is connected to the water supply pipe (not shown) of the water supply pipe 38 through a pipe 50 penetrating the side wall of the container 4. It is connected to.

The control device 14 is constituted by a personal computer which operates according to a predetermined program.
The solenoid valves 36 and 42 are controlled based on the output signal of the pressure gauge 10 and the blower 8 is controlled.

Next, the operation of the air purification device 2 configured as described above will be described. When the operator operates the control device 14 to instruct activation of the blower 8, the control device 14 sends a predetermined signal to the blower 8 to turn on the power of the blower 8. As a result, the blower 8 starts blowing air, sucks the contaminated air from the tube 30, and sends the contaminated air into the lower space 20 of the container 4 through the tube 26. The contaminated air sent into the lower space portion 20 passes through the soil layer 6 having a high porosity and exits the container from the upper surface of the soil layer 6.

When the contaminated air passes through the soil layer 6, dust is trapped by the physical action of a soil filter, and impurities such as hydrocarbon gas such as methane are adsorbed. In addition, microorganisms in the soil layer 6 decompose contaminants such as impurity components. Aerobic microorganisms proliferate on the surface of the soil layer 6 or on a portion where air flows inside the soil layer 6, and anaerobic microorganisms proliferate on a portion where air does not flow inside the soil layer 6. Therefore, for example, carbon monoxide is mainly converted into carbon dioxide and methane gas is mainly decomposed into carbon dioxide and water by being consumed in the cells of these microorganisms or used for respiration. As a result, clean air from which contaminants have been removed is returned to the atmosphere from the surface of the soil layer 6.

In order for such an air purifying action to be effectively exerted, the amount of water contained in the soil layer 6 must be appropriate. In this embodiment, the amount of water in the soil layer 6 is as follows. It is controlled as follows. That is, the pressure gauge 10 connected to the lower space 20 of the container 4 through the pipe 32
The static pressure in the lower space 20 is constantly measured, and an electric signal indicating the measurement result is output to the control device 14. The static pressure in the lower space 20 changes depending on the amount of water contained in the soil layer 6. For example, when the amount of water contained in the soil layer 6 is small, the air easily passes through the soil layer 6, and therefore, the pressure in the lower space 20 has a low value. Conversely, when the amount of moisture contained in the soil layer 6 is large, the air hardly passes through the soil layer 6, and therefore, the pressure in the lower space portion 20 has a high value.

The control device 14 obtains the static pressure of the lower space portion 20 from the electric signal from the pressure gauge 10, and in the present embodiment, as an example, when the static pressure becomes 35 mmAq or less, the solenoid valves 36 and 42 are used. An electric signal is sent to each valve to open each valve. As a result, the shower nozzle 34 and the water supply pipe 40
More water spouts out, and water is supplied to the soil layer 6 from both the surface and the inside of the layer, and water is replenished.

When nitrogen oxides are removed by the soil layer 6, it is known that the water content of the soil layer 6 becomes optimal when the pF is about 1.5. Further, as described above, the soil layer 6 of the present embodiment is composed of black ando, mulch, and pearlite:
They are mixed at a ratio of 1: 1 and the thickness of the soil layer 6 is 40 cm. In the case of such a soil layer 6, p
The reason why F becomes 1.5 is that the static pressure of the lower space 20 is 35 m.
It was experimentally confirmed that the time was mAq. Therefore, in this embodiment, the static pressure is set to 3 as described above.
When the pressure becomes 5 mmAq or less, the solenoid valves 36 and 42 are opened to supply water.

As a result of supplying water to the soil layer 6 as described above,
Although the amount of water contained in the soil layer 6 increases and the static pressure in the lower space 20 also increases, the change in the static pressure is as shown in the graph of FIG. In the figure, the horizontal axis represents time (minutes),
The vertical axis represents the static pressure (mmAq). A polygonal line A represents a change in static pressure, and is a plot of actual measurement results. When the solenoid valves 36 and 42 are opened and water is supplied at 0 minute on the horizontal axis, the static pressure immediately rises, and then 60 mm
It is a constant value of about Aq. Then, it gradually falls from around 15 minutes, and changes gradually after 30 minutes.

In this embodiment, the control device 14 controls the solenoid valve 3
6 and 42 are opened to start water supply. When 30 minutes have elapsed, the lower space 2 is again detected by an electric signal from the pressure gauge 10.
If a static pressure of 0 is acquired and the value exceeds 35 mmAq, it is determined that the amount of water contained in the soil layer 6 is sufficient, and the solenoid valves 36 and 42 are controlled to close each valve, and the shower nozzle 34 And the water supply from the water supply pipe 40 is stopped.

Thereafter, the controller 14 monitors the electric signal from the pressure gauge 10 and, when the static pressure becomes 35 mmAq or less, opens the solenoid valves 36 and 42 in the same manner as described above, and Replenish the water for 6. As a result, the water content of the soil layer 6 is automatically maintained at a value at which the air purification action is effectively exerted.

In this embodiment, the dryness of the soil layer
Therefore, the amount of water contained in the soil layer is monitored by the pressure in the air chamber, and since the pF meter is not used, the water content of the entire soil layer 6 is monitored without disposing the pF meter at various places in the soil layer 6. It has become possible. Therefore, the apparatus does not become unnecessarily large, and is advantageous in reducing the cost. Further, the problem that the pF meter is easily broken and maintenance is required can be avoided.

In this embodiment, the contaminated air is pressure-fed into the lower space 20 by the blower 8. However, the blower 8 is mounted in the opposite direction, and the air is sucked from the lower space 20 to form the soil layer 6. It is also possible to adopt a configuration in which contaminated air is sucked from the surface. However, in this case, as the soil layer contains more water, air becomes more difficult to pass and the pressure in the lower space 20 decreases, and conversely, as the soil layer dries, the pressure in the lower space 20 increases. . Therefore, in this configuration, when the pressure in the lower space 20 exceeds a certain value, the solenoid valves 36, 4
2 is controlled to supply water to the soil layer.

Next, a second embodiment will be described. FIG.
FIG. 4 is a schematic explanatory view showing a second air purification device 44 for performing the air purification method of the present invention. The configuration of the air purification device 44 is similar to the air purification device 2 shown in FIG.
The controller 14 controls the solenoid valves 36 and 42 based on the frequency of the current.

As described above, the ease of passage of air changes depending on the amount of water contained in the soil layer 6. This means that the weight of the load on the blower 8 changes depending on the amount of water contained in the soil layer 6. Means that. Therefore, soil layer 6
The frequency of the current supplied from the inverter 46 to the blower 8 changes in accordance with the water content of the inverter 46. Actually, the water content of the soil layer 6 and the frequency of the output current of the inverter 46 are as shown in FIG. In addition, it was confirmed that the relationship was almost proportional. In the figure, the horizontal axis represents the frequency of the output current of the inverter 46, and the vertical axis represents the water content of the soil layer 6, that is, pF.

The soil layer 6 is a mixture of ando, mulch, and perlite at a ratio of 3: 1: 1. When the thickness of the soil layer 6 is 40 cm, the pF is 1.5. Can be experimentally confirmed that the frequency of the output current of the inverter 46 is 55 Hz.

The air purifying device 44 of the second embodiment utilizes such a fact, and the control device 14 monitors the frequency of the output current of the inverter 46 and adjusts the frequency to 55H.
When the value is equal to or less than z, the solenoid valves 36 and 42 are opened to supply water to the soil layer 6. As a result of supplying water to the soil layer 6 in this manner,
Although the amount of moisture contained in the soil layer 6 increases and the frequency of the output current of the inverter 46 also increases, the change in the frequency is as shown in the graph of FIG. In the figure, the horizontal axis represents time (minutes), and the vertical axis represents frequency (Hz). A polygonal line B represents a change in frequency, and is a plot of actual measurement results. At 0 minute on the horizontal axis, the solenoid valves 36, 4
When opening 2 and supplying water, the frequency rises immediately,
After that, it becomes a constant value of about 100 Hz. And 15
After about 30 minutes, it gradually descends and changes gradually after 30 minutes.

In this embodiment, the control device 14 controls the solenoid valve 3
6 and 42 are opened to start water supply, and when 30 minutes have elapsed, if the frequency exceeds 55 Hz, it is determined that the amount of water contained in the soil layer 6 is sufficient, and the solenoid valves 36 and 42 are determined.
Is controlled to close each valve, and the water supply from the shower nozzle 34 and the water supply pipe 38 is stopped.

Thereafter, the control device 14 monitors the output current of the inverter 46, and when the frequency becomes 55 Hz or less, the solenoid valves 36 and 42 are opened and the Replenish hydration. As a result, the water content of the soil layer 6 is automatically maintained at a value at which the air purification action is effectively exerted.

In this embodiment, the dryness of the soil layer
Therefore, the amount of water contained in the soil layer is monitored by the frequency of the output current of the inverter 46, and the pF meter is not used. Can be monitored. Therefore, the apparatus does not become unnecessarily large, and is advantageous in reducing the cost. Further, the problem that the pF meter is easily broken and maintenance is required can be avoided.

In the case of the second embodiment, as in the case of the first embodiment, the blower 8 is mounted in the opposite direction, air is sucked from the lower space 20, and the soil layer 6 is removed. It is also possible to adopt a configuration in which contaminated air is sucked from the surface.
Also in this case, since the frequency of the output current of the inverter decreases as the soil layer dries, water is supplied when this frequency becomes lower than a certain value.

In the first and second embodiments, water supply is started when the static pressure is 35 mmAq or less and the frequency is 55 Hz or less, respectively. However, the relationship between the pF value and the static pressure and frequency is determined by the soil type. The threshold values of the static pressure and the frequency are set appropriately by grasping the relationship between the pF value and the static pressure and the frequency for each individual device because the values vary depending on the layer thickness, the type of the mixed material, and the like. It should be.

In the above embodiment, the water is supplied to the soil layer 6 by both the shower nozzle 34 provided above the soil layer 6 and the water supply pipe 40 buried in the soil layer 6. It is not necessary to use both at the same time, and it is also possible to adopt a configuration in which only one of them is provided.
When water is sprinkled from above the soil layer 6, it is of course possible to use the same type as the water supply pipe 38 instead of the shower nozzle 34.

Further, as a method of replenishing water to the soil layer, as shown by an imaginary line in FIG. 1, a spray nozzle 48 is provided in the middle of the tube 26, and water is atomized from this nozzle to form the tube 26. It is also possible to spray water into the soil layer together with the contaminated air to replenish moisture.

In the above embodiment, the shower nozzle 3
The supply of water to the shower nozzle 34 and the water supply pipe 40 was performed by controlling the pumps instead of the solenoid valves. Of course, control is also possible.

[0042]

As described above, in the method of purifying contaminated air according to the present invention, water is supplied to the soil layer based on the pressure of the contaminated air fed to the soil layer or the contaminated air sucked through the soil layer. Further, in the present invention, the blower is operated by supplying a current by the inverter, and the contaminated air is pumped to the soil layer or the contaminated air is sucked through the soil layer,
The inverter supplies water to the soil layer based on the frequency of the current supplied to the blower.

Therefore, according to the present invention, the soil layer can be automatically adjusted so as to always contain an appropriate amount of water, and the air purification action of microorganisms and soil can be efficiently exhibited. In the present invention, since it is not necessary to use a pF meter for monitoring the water content, it is possible to monitor the water content of the entire soil layer without arranging a pF meter in each part of the soil layer. However, there is no need to increase the size more than necessary, which is advantageous for further cost reduction. Further, the problem that the pF meter is easily broken and maintenance is required can be avoided.

[Brief description of the drawings]

FIG. 1 is a schematic explanatory view showing an example of an air purification device for implementing a method for purifying contaminated air of the present invention.

FIG. 2 is a graph for explaining the operation of the air purification device of FIG.

FIG. 3 is a schematic explanatory view showing another example of an air purification device for carrying out the method for purifying contaminated air of the present invention.

FIG. 4 is a graph showing a relationship between a frequency of an output current of an inverter included in the air purification device of FIG. 3 and a water content of a soil layer.

FIG. 5 is a graph for explaining the operation of the air purification device of FIG. 3;

[Description of Signs] 2,44 Air purification device 4 Container 6 Soil layer 8 Blower 10 Pressure gauge 12 Water supply device 14 Control device 20 Air chamber 26, 30, 32, 50 Tube 34 Shower nozzle 36, 42 Electromagnetic valve 38, 40 Water supply pipe 46 Inverter 48 Spray nozzle

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Shinichiro Sato 4-6-115 Sendagaya, Shibuya-ku, Tokyo Inside Fujita Co., Ltd. (72) Inventor Takehiko Shimada 1st Toyota Town, Toyota City, Aichi Prefecture Toyota Motor Corporation (72) Inventor Kazushi Takahashi 1 Toyota Town, Toyota City, Aichi Prefecture Inside Toyota Motor Corporation (72) Inventor Yasuhiro Tsuchiya 1 Toyota Town, Toyota City, Aichi Prefecture Inside Toyota Motor Corporation

Claims (9)

[Claims] 1. A method for purifying contaminated air by pumping and passing contaminated air through a soil layer in which microorganisms can propagate and through which air can flow, wherein the contaminated air is pumped to the soil layer. A method for purifying contaminated air, comprising: measuring the pressure of air; and supplying water to the soil layer based on the measured pressure of the contaminated air. 2. A contaminated air purification method for purifying contaminated air by suctioning contaminated air through a soil layer in which microorganisms can propagate and air can flow, wherein a pressure of the air sucked through the soil layer is measured. And replenishing the soil layer with water based on the measured air pressure. 3. The soil layer is formed in a container,
The method according to claim 1, wherein the pressure is measured in the container. 4. The method according to claim 1, wherein the pressure is a static pressure of the contaminated air or the sucked air. 5. A contaminated air purification method for purifying contaminated air by passing contaminated air through a soil layer in which microorganisms can propagate and air can flow, wherein an inverter supplies current to operate a blower. Pumping the contaminated air to the soil layer, measuring the frequency of the current supplied to the blower by the inverter, and supplying water to the soil layer based on the measured frequency. Air purification method. 6. A contaminated air purification method for purifying contaminated air by passing the contaminated air through a soil layer in which microorganisms can propagate and through which air can flow, wherein a blower is operated by supplying an electric current by an inverter. Sucking the contaminated air through the soil layer, measuring the frequency of the current supplied to the blower by the inverter, and replenishing the soil layer with water based on the measured frequency. Air purification method. 7. The method for purifying contaminated air according to claim 1, wherein water is supplied to the surface of the soil layer to supply water to the soil layer. 8. The method for purifying contaminated air according to claim 1, wherein water is supplied to the soil layer through a pipe buried in the soil layer, and moisture is supplied to the soil layer. . 9. The method for purifying contaminated air according to claim 1, wherein water is atomized and mixed with the contaminated air to be pumped to the soil layer to supply water to the soil layer.