JPH11166720A - Dust trap assembly - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the pressure drop in an air flow and surely trap and remove dust in the air flow to guide a clean air to an air flow rate sensor. SOLUTION: The assembly comprises an inlet 36 below a case 38, outlet 37 above it, main air flow passage 40 having an inlet facing the inlet 36, dust flow passage 41 having an inlet facing the inlet 36, first trap wall 43 formed by bending the side wall 49 of the main passage 40 at the common inlet of both passages 40, 41, second trap wall 44 formed by bending a side wall 50 at the downstream thereof, and third trap wall 45 at the upstream thereof, so that the trap walls 43, 44, 45 trap dust 39 in the air flow and guide it to the dust passage 41 to contact resulting clean air flow contg. no dust 39 to an air flow rate sensor 16 disposed in a straightening section 51 of the main passage 40, thereby blowing it out of the outlet 37a.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention captures and removes dust (dust) in the air which is provided to a combustion device such as a water heater or a bath kettle and is guided to a flow rate detection sensor for detecting a flow rate of combustion air. The present invention relates to a dust trap device.

[0002]

2. Description of the Related Art FIG. 3 shows a system configuration of a water heater under development by the applicant. In FIG.
The apparatus main body 2 is accommodated therein, and a combustion chamber 3 is provided inside the apparatus main body 2, and a burner 4 is installed below the combustion chamber 3. A gas nozzle 7 attached to a nozzle header 6 is opposed to the gas introduction section 5 of the burner 4, and a gas supply passage 8 is connected to the nozzle header 6. The gas supply passage 8 has a nozzle header 6
Valve 10 for supplying and shutting off gas to the burner 4 and proportional valve 11 for controlling the supply amount of gas to the burner 4 by the opening amount
And an original solenoid valve 12 for opening and closing the gas supply passage 8. A combustion fan 13 for supplying and discharging burner combustion is provided below the burner 4, and an air chamber 14 is formed between the combustion fan 13 and the burner 4.

[0003] Between the air chamber 14 and the combustion chamber 3, there is provided an air distribution passage 15 for taking in and flowing a part of the combustion air supplied from the combustion fan 13 to the burner 4. An airflow detection sensor 16 that detects the airflow of the combustion air supplied from the combustion fan 13 to the burner 4 is provided in the branch passage 15. The air volume detection sensor 16 is constituted by an appropriate sensor having a function of directly or indirectly detecting the air volume, such as a hot-wire heater type wind speed sensor or a differential pressure sensor.

[0004] Above the combustion chamber 3 is a hot water supply heat exchanger 1
A water supply passage 18 is connected to the inlet side of the hot water supply heat exchanger 17. The water supply passage 18 has a water amount sensor 20 for detecting a water supply flow rate and a water supply temperature sensor 21 for detecting a water supply temperature. Is provided. A hot water supply passage 22 is connected to the outlet side of the hot water supply heat exchanger 17, and the hot water supply passage 22 is provided with a hot water supply temperature sensor 23 for detecting a hot water supply temperature and a water amount control valve 24 for controlling a hot water supply flow rate.

The operation of the water heater is controlled by a controller 25, to which a remote controller 26 for setting operating conditions such as hot water temperature is connected by signal.

[0006] The control device 25 controls the gas supply amount by the opening amount of the proportional valve 11 so that the hot water supply temperature becomes the hot water supply set temperature set by the remote controller 26, and also controls a predetermined appropriate air-fuel ratio. The rotation of the combustion fan 13 is controlled so as to be as follows. The control of the air volume of the combustion air will be described in more detail. The control device 25 is provided with data on the relationship between the amount of combustion heat and the amount of air supplied (air volume), and the target air volume corresponding to the required combustion heat amount obtained by calculation. And controls the rotation of the combustion fan 13 so that the air volume detected by the air volume detection sensor 16 becomes the target air volume. In FIG. 3, reference numeral 27 denotes a fan rotation detection sensor that detects the rotation of the combustion fan 13 per unit time.

[0007]

As described above, a part of the combustion air supplied from the combustion fan 13 to the burner 4 is diverted through the air distribution passage 15 to detect the fan airflow.
By performing the rotation control of the combustion fan 13 based on the air volume detection information, a suitable air-fuel ratio control in which the amount of combustion heat and the air volume match can be performed. However, combustion fan 1
The air taken in from the outside by 3 contains dust such as dust and trash, and the air volume detection sensor 16 directly contacts the air passing through the air branch passage 15 to detect the air volume. Adheres to the air volume detection section, and as the amount of dust attached increases, the air volume detection performance of the air volume detection sensor 16 deteriorates, and the reliability of long-term air volume detection is impaired. There is a problem that the accuracy of the fuel ratio control is also reduced.

In order to solve such a problem, the applicant has been studying a dust trap device incorporating an air volume detection sensor 16 as shown in FIG.

In the dust trap device of this study, a trap passage 31 is formed on the front surface side of a body 30 via a partition 30 and a sensor installation space 32 is formed on the back surface side as shown in FIG. . In the trap passage 31, trap walls 33 are formed so as to alternately overlap and protrude from both side walls of the passage at right angles. A partition wall 34 for partitioning the left and right trap passages 31 is provided at the center, and the left and right trap passages 31 communicate with each other via the sensor installation space 32.

That is, a communication hole 35a communicating with one end of the sensor installation space 32 is formed in the left trap passage connected to the partition wall 34, and a communication hole 35a is formed in the right trap passage 31 at the other end of the sensor installation space 32. A communication hole 35b for communication is provided, and the flow of the wind introduced from the inlet 36 of the trap passage 31 on the left side is guided to the sensor installation space 32 on the back side through the communication hole 35a through the trap passage 31 on the left side. The wind passing through the space 32 is guided from the communication hole 35b to the right trap passage 31 formed on the surface side, and is sent out from the outlet 37 of the trap passage 31 through the right trap passage 31. I have.

The sensor installation space 32 is a space of a straight path connecting the communication holes 35a, 35b arranged side by side via the partition wall 34 at the shortest distance. A detection sensor 16 is provided. In this dust trap device, the inlet side 36 is set to the air chamber 14 side, and the outlet side 37 is set to the combustion chamber 3 side, and is provided in the air distribution passage 15.

In this dust trap device, a plurality of trap walls 33 are formed alternately in the trap passage 31 so as to protrude with their leading ends overlapping, so that the flow of combustion air flowing therethrough is indicated by arrows in FIG. As described above, the trap wall 33 bends in a zigzag direction in a substantially 90 ° direction to meander, and when the wind is bent by the trap wall 33, the dust contained in the air reduces the inertia force in the straight traveling direction. In order to receive the air flow detection sensor 1, the vehicle cannot make a sharp turn, but hits the trap wall 33, hinders advancement, captures and removes dust, and enters the dust-removed wind into the sensor installation space 32.
6 prevents dust from adhering to the air volume detection unit, guarantees the air volume detection accuracy of the air volume detection sensor 16 for a long time,
The purpose is to improve the accuracy and reliability of air volume detection.

However, the dust trap device under study shown in FIG. 4 has a configuration in which the tip side of the trap wall 33 is overlapped from the trap passage 31 and the trap wall 33 projects in a substantially perpendicular direction in a zigzag manner. Since the flow of the wind passing through the passage 31 alternately changes the direction of the flow by approximately 90 ° and progresses in a zigzag manner, there occurs a problem that the pressure loss becomes extremely large, and the accurate air volume is accurately detected by the air volume detection sensor 16. There is a problem that it cannot be detected.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to minimize the pressure loss of an air flow so as to reliably capture and remove dust in air, and to capture and remove dust. It is an object of the present invention to provide a dust trap device capable of guiding the cleaned clean air to an airflow detection sensor.

[0015]

Means for Solving the Problems In order to achieve the above object, the present invention has the following structure to solve the problems. That is, in the first invention, the main flow path and the dust flow path of the air flow are provided in the case where the inlet and the outlet of the air flow are provided at different positions, with the inlet side opposed to the air flow inlet. The present invention solves the problem by having a configuration in which a first trap wall that captures dust in an air flow and guides the dust to the dust flow path side is provided at a common inlet side of the dust flow path and the main flow path. Means.

According to a second aspect of the present invention, in addition to the configuration of the first aspect, a dust path is formed between the side wall of the main flow path and the case, and the main flow path at the inlet side of the main flow path. This is a means for solving the problem by having a configuration in which the side wall of the flow path is bent and the bent wall portion is formed as a first trap wall.

Further, according to the third invention, in addition to the structure of the first or second invention, a side wall of the main flow path opposite to the first trap wall is provided on a downstream side near the first trap wall. The second means for solving the problem has a configuration in which a second trap wall for capturing dust in the airflow is provided to protrude inward of the main flow path.

Further, in the fourth invention, in addition to the structure of the first, second, or third invention, the second trap wall is formed on an inlet side wall of the main flow path opposite to the first trap wall. It is a means for solving the problem by having a structure in which a gap is formed between the case and the main flow path side wall on the side where the second trap wall is formed.

Further, in accordance with the fifth aspect of the present invention, in addition to the configuration of the third or fourth aspect, the dust in the airflow is provided between the second trap wall and the case on the upstream side of the second trap wall. The third trap wall for trapping is formed so as to protrude in the same direction as the second trap wall, and is a means for solving the problem.

Further, in the sixth invention, in addition to the configuration of the fifth invention, a gap is formed between the second trap wall and the base end side of the third trap wall, and the gap is formed by dust. This is a means for solving the problem by having a configuration communicating with the flow path.

Further, according to a seventh aspect of the present invention, in addition to the configuration of any one of the first to sixth aspects, the air flow path is provided in a vertical direction, and the case has a trap. The present invention has a configuration in which a dust receiving portion for receiving dust falling from a wall is provided as means for solving the problem.

Further, in the eighth invention, in addition to the constitution of any one of the first to seventh inventions, a rectification section is provided in the main flow path, and the rectification section is provided in the rectification section. Is a means for solving the problem by having a configuration in which an air flow detection sensor for detecting the flow rate of the air flow is provided.

In the present invention having the above-described structure, the first inlet wall of the dust flow path and the main flow path is provided with the first trap wall that captures dust in the air flow and guides the dust to the dust flow path. The dust in the air flow entering from the inlet of the device is captured by the first trap wall and guided to the dust flow path side, and proceeds to the outlet side of the device through the dust flow path, while the dust is captured by the first trap wall. The removed clean air passes through the main flow path to the outlet side of the device. As described above, in the present invention, the dust flow path and the main flow path are separately provided in the apparatus, and the dust in the air flow is captured by the first trap wall and guided to the dust flow path side. By providing the airflow detection sensor on the flow path side, it becomes possible to guide clean air from which dust has been captured and removed to the airflow detection sensor.

Further, in the present invention, since the air flow advances while being divided into the dust flow path and the main flow path, the occurrence of a pressure loss as in the case where the air flow changes direction by 90 ° zigzag is prevented. Thus, the pressure loss of the air flow can be reduced. for that reason,
The pressure loss of the air flow is made as small as possible, dust in the air is reliably captured and removed, and clean air from which the dust has been captured and removed can be guided to the air volume detection sensor.

[0025]

Embodiments of the present invention will be described below with reference to the drawings. Note that the dust trap device of the present embodiment is an air distribution passage 1 of the water heater shown in FIG.
The same components as those described with reference to FIG. 3 are denoted by the same reference numerals, and redundant description thereof will be omitted.

FIG. 1 is a sectional view showing an embodiment of a dust trap device according to the present invention. In the figure, an inlet 36 for introducing air flow into the case is provided below the case 38, and an outlet 37 is formed above the case 38. In the case 38, a main flow path 40 for the air flow and a dust flow path 41 are provided with the respective inlet sides facing the inlet 36 for the air flow, and the common flow path of the dust flow path 41 and the main flow path 40 is provided. On the inlet side, a first trap wall 43 that captures dust 39 in the air flow and guides the dust 39 to the dust flow path 41 side is provided obliquely with respect to the flow path of the air flow. In this embodiment, the main flow path 4
0 between the side walls 49 and 50 and the case 38
The first trap wall 43 is formed by bending the side wall 49 of the main flow path 40 on the inlet side.

On the downstream side near the first trap wall 43, a side wall 50 of the main flow path 40 opposite to the first trap wall 43 is provided.
A second trap wall 44 is provided to project obliquely inward of the main flow path 40 from the side, and the second trap wall 44 also captures dust in the airflow similarly to the first trap wall 43. Has a function. In the present embodiment,
The second trap wall 44 is formed by bending a side wall 50 opposite to the first trap wall 43 on the inlet side of the main flow path 40, and as described above, the side wall 50 on the side where the second trap wall 44 is formed and the case are formed. The gap between the first and second dust passages 38 forms a dust flow path 41.

On the upstream side of the second trap wall 44, between the second trap wall 44 and the case 38, a third trap wall 45 for catching dust 39 in the air flow is provided in the same direction as the second trap wall. A gap 42 is formed between the second trap wall and the proximal end 47 of the third trap wall 45, and the gap 42 communicates with the dust flow path 41.

In the present embodiment, the flow path of the air flow is provided in the vertical direction, and the case 38 receives the dust 39 falling from the first, second, and third trap walls 43, 44, 45. A receiving portion 46 is provided. A rectification section 51 is provided on the downstream side of the main flow path 40 (on the side of the outlet 37a), and the rectification section 51 is provided with an air volume detection sensor 16 for detecting the flow rate of the air flow.

In this embodiment, the flow of the air entering from the inlet 36 is mostly turned to the left in the figure and proceeds to the main flow path 40 side. The dust 39 cannot follow the air flow because the inertia force of the dust 39 tries to go straight in the tangential direction of the path of the air flow, and the dust 39 cannot bend to the left side of the drawing due to the inertia force of the dust 39. Then, it collides with the first trap wall 43, is captured by the first trap wall 43, and proceeds to the outlet 37b side through the dust flow path 41 on the right side in the figure. Then, the air that has proceeded to the main flow path 40 turns to the left in the figure and then to the left as shown by the chain line arrow in FIG. As described above, the dust 39 cannot follow the direction of the air flow due to the inertial force of the dust 39, and
It collides with the trap walls 44, 45, is captured by the second and third trap walls 44, 45, and proceeds to the outlet 37b side through the dust channel 41 on the left side in FIG.

Therefore, the flow toward the outlet 37a through the main flow path 40 downstream of the second trap wall 44 becomes a clean air flow containing no dust 39, and this clean air flow is used as the air flow detection sensor 16 And is sent out from the outlet 37a.

When the combustion fan 13 of the water heater stops and the flow of air from the inlet 36 to the outlet 37 of the trap device stops, the first, second, and third trap walls 43, 4 are provided.
4 and 45 and the dust 39 from the dust passage 41
, And the dust 39 is stored in the dust receiver 46.

According to the present embodiment, as described above, the dust flow path 41 and the main flow path 40 are provided, and the dust 39 in the air flow is moved by the first, second, and third trap walls 43, 44, 4
The air flow sent to the air flow detection sensor 16 through the main flow passage 40 through the main flow passage 40 can be a clean air flow containing no dust, because the air flow is captured by the air flow 5 and guided to the dust flow passage 41 side. In addition, the first, second and third trap walls 4
3, 44 and 45 are provided to project obliquely, so that the air flow does not change its direction in a 90 ° zigzag direction and the pressure loss of the air flow can be reduced. Become.

Therefore, according to the present embodiment, the pressure loss of the air flow is reduced to reliably capture and remove the dust 39 in the air. 16, the air flow detection sensor 16 detects the air distribution passage 1 of the water heater.
5 can be accurately detected.

According to this embodiment, the second trap wall 44 is provided on the downstream side in the vicinity of the first trap wall 43, and the third trap wall 4 is provided on the upstream side of the second trap wall 44.
5, the dust 39 can be captured very efficiently and reliably. Thus, not only the first trap wall 43 but also the second and third trap walls 4 can be trapped.
By providing the holes 4, 45, the effect of trapping and removing the dust 39 in the air flow can be further ensured.

Further, according to this embodiment, the gap 42 is formed between the second trap wall 44 and the base end 47 of the third trap wall 45, and the main flow path on the side where the second trap wall 44 is formed is formed. A gap is formed between the side wall 50 of the case 40 and the case 38 to form a dust channel 41, and the gap 42 is formed in the dust channel 41.
The dust 39 captured by the second trap wall 44 passes through the gap 42 at a very high flow rate, is guided to the dust flow path 41 side, and passes through the dust flow path 41 to the outlet 37b. Can be guided to the side. Therefore, for example, the pressure loss in the area where the second trap wall 44 is provided can be reduced as compared with a case where the gap 42 is not provided, and the dust 39 captured by the second trap wall 44 The effect of guiding to the side can be exhibited very efficiently.

Further, in the present embodiment, the air flow path is provided vertically and the case
The dust 39 falling from each of the trap walls 43, 44, 45 and the dust flow path 41 can be received by the dust receiving portion 46 when the combustion fan 13 of the water heater is stopped or the like. Therefore, when the combustion fan 13 is driven again after the stop of the combustion fan 13 to flow air from the inlet 36 to the outlet 37 of the trap device, it is possible to suppress the falling dust 39 from flying up. The dust 39 can be more efficiently removed.

The apparatus shown in FIG.
Since the communication holes 35a and 35b are disposed adjacent to each other via the first through hole 4 and the sensor installation space 32 is provided in such a manner that the communication holes 35a and 35b are connected at the shortest distance in a straight line, the sensor installation space is provided from the communication hole 35a side. The wind entering the space 32 is bent at a right angle, and the flow path fluctuates due to the bending of the course thereof. Since the straight path of the sensor installation space 32 is short, the wind that is bent at a right angle from the communication hole 35a and enters the space 32 has a flow velocity fluctuation. The air volume detection sensor 16
And the air volume is detected.

As a result, there is a problem in that the detected value of the air flow varies due to the variation in the flow velocity, and the accurate air flow cannot be accurately detected. However, according to the present embodiment, the rectification is performed on the outlet 37a side of the main flow passage 40. Since the section 51 is provided and the air flow rate detection sensor 16 is provided in the rectification section 51, the rectified air is eliminated by eliminating the variation in the flow velocity fluctuation through the main flow path 40 and the path toward the outlet 37a side. Since the flow contacts the air flow detection sensor 16, the air flow of the air flow can be detected very accurately, and the air flow of the combustion fan 13 can be accurately detected.

It should be noted that the present invention is not limited to the above-described embodiment, but can adopt various embodiments. For example, in the above embodiment, the gap 42 is formed between the second trap wall 44 and the base end 47 of the third trap wall 45. However, as shown in FIG. Omitted and second
The trap wall 44 may communicate with the base end 47 of the third trap wall 45. However, the second trap wall 44 and the third
If the gap 42 is provided between the trap wall 45 and the base end 47 as in the above-described embodiment, the flow rate of the air flowing through the gap 42 increases, so that the dust trapped by the second trap wall 44 is removed. The dust can be efficiently guided to the outlet 37b side of the dust passage 41 through the dust passage 41.

In the above embodiment, a gap is formed between the main channel side wall 50 on the side where the second trap wall 44 is formed and the case 38 to form the dust channel 41.
As shown in (b) of FIG.
8 may be provided to protrude inside the main flow path 40.

Further, in the above-described embodiment, the first, second, and third trap walls 43, 44, and 45 are provided one by one. However, for example, a plurality of third trap walls 45 may be provided. The third trap wall 45 and the second trap wall may be omitted. However, by providing the second trap wall 44 near the downstream side of the first trap wall 43, even if the dust 39 in the airflow cannot be completely removed by the first trap wall 43, the second trap wall 44 may be provided. 44
Can remove the dust 39, and
By providing the third trap wall 45, the effect of trapping and removing the dust 39 in the airflow can be more effectively exerted. Therefore, it is desirable to provide the second trap wall 44 and the third trap wall 45. .

Furthermore, in the above embodiment, the dust trap 46 is formed by providing the dust receiver 46 in the case 38, but the dust receiver 46 can be omitted. However, by providing the dust receiver 46, for example, the dust 3 dropped from the trap wall or the like while the combustion fan 13 is stopped.
It is preferable to provide the dust receiver 46 in order to receive the dust 9 in the dust receiver 46 and to surely prevent the dust 39 from rising when the combustion fan 13 is driven next time.

Further, in the above embodiment, the case 38
The inlet 36 is provided on the lower side, and the outlet 37 is provided on the upper side.
May be provided on one of the left and right sides of the case 38, and the outlet 37 may be provided on the other of the left and right sides of the case 38. The road may be provided diagonally.

Further, in the above-described embodiment, the example in which the dust trap device is provided in the water heater is shown. However, the present invention is applied to various other combustion equipment other than the water heater, for example, a bath pot, a bath / combined water heater, and the like. It is also possible to apply the present invention as a device that removes dust components in the intake air flow other than the combustion equipment and detects the wind speed by a flow rate detection sensor.

[0046]

According to the present invention, a dust channel and a main channel are provided, and a first trap wall which captures dust in the air flow and guides the dust to the dust channel is provided at a common inlet side of these channels. Since it is provided, the dust component in the air flow can be captured and guided to the dust flow path side, and the clean air from which the dust has been captured and removed can be guided to the main flow path and sent out from the main flow path.

According to the present invention, as described above, in order to divide the air flow into the main flow path and the dust flow path and guide the air flow to the outlet side, for example, the air flow is changed in a 90 ° zigzag direction. Unlike a device that removes dust, the pressure loss is reduced to reliably capture and remove dust in the air.For example, by installing an air volume detection sensor in a rectification section provided in the main flow path, dust can be captured and removed. The clean air is guided to the airflow detection sensor, and the airflow of the airflow can be accurately detected by the airflow detection sensor.

Further, a dust path is formed between the side wall of the main flow path and the case, and the side wall of the main flow path on the inlet side of the main flow path is bent to form the bent wall portion as the first trap wall. According to the present invention, it is possible to very easily form the first trap wall using the side wall of the main flow path without waste, and to form a dust trap device having the above-described excellent effects.

Further, on the downstream side in the vicinity of the first trap wall, a second trap wall for capturing dust in an air flow is provided on the inner side of the main flow path from the side wall of the main flow path opposite to the first trap wall. According to the present invention which is provided so as to protrude in the direction, the dust trapping and removing effect can be further enhanced by the second trap wall.

Further, the second trap wall is formed by bending an inlet side wall of the main flow path opposite to the first trap wall, and is formed between the main flow path side wall on the side where the second trap wall is formed and the case. According to the present invention in which a gap is formed between the case and the second trap wall, the dust trapped by the second trap wall is efficiently guided to the outlet through the gap between the main flow path side wall and the case. Can be.

Further, on the upstream side of the second trap wall, a third trap wall for trapping dust in the airflow is formed between the second trap wall and the case so as to protrude in the same direction as the second trap wall. According to the present invention, by providing the third trap wall, the effect of capturing dust in the airflow can be further enhanced.

Further, according to the present invention, a gap is formed between the second trap wall and the base end side of the third trap wall, and the gap communicates with the dust flow path. The dust caught by the method can be efficiently guided to the dust flow path side by being put on an airflow having a high flow velocity passing through the gap, and can be removed through the dust flow path.

Furthermore, according to the present invention, the air flow path is provided in the vertical direction, and the case is provided with a dust receiving portion for receiving dust falling from the trap wall. By receiving the dust that has fallen from the trap wall when the flow stops, the dust receiver can reliably prevent the dust from rising when the air flows again. Can be exhibited more effectively.

Furthermore, a rectification section is provided in the main flow path, and an air flow rate detection sensor for detecting a flow rate of the air flow is provided in the rectification section. The air flow can be detected very accurately by bringing the air into contact with the air flow detection sensor.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing a cross-sectional view of an embodiment of a dust trap device according to the present invention.

FIG. 2 is a configuration explanatory view showing a cross-sectional view of another embodiment of the dust trap device according to the present invention.

FIG. 3 is an explanatory diagram of a system configuration of a water heater in which the dust trap device of the embodiment is used.

FIG. 4 is an explanatory diagram of a configuration of a dust trap device studied by the applicant.

FIG. 5 is a cross-sectional view of communication holes 35a and 35b in FIG.

[Explanation of symbols]

 38 case 40 main flow path 41 dust flow path 42 gap 43 first trap wall 44 second trap wall 45 third trap wall 46 dust receiver 47 base end side

Claims (8)

[Claims] An air flow main flow path and a dust flow path are provided in a case provided with an air flow inlet and an air outlet at different positions, with the inlet side facing the air flow inlet, respectively. A dust trap device, wherein a first trap wall is provided at a common inlet side of the dust flow path and the main flow path to capture dust in an air flow and guide the dust to the dust flow path. 2. A dust path is formed between a side wall of the main flow path and the case, and a side wall of the main flow path on the main flow path inlet side is bent to form the bent wall portion as a first trap wall. The dust trap device according to claim 1, wherein the dust trap device is formed. 3. The first trap wall is located downstream of the first trap wall.
The second trap wall for trapping dust in the air flow from a side wall of the main flow path opposite to the trap wall is provided so as to protrude inward of the main flow path. 3. The dust trap device according to 2. 4. The second trap wall is formed by bending an inlet side wall of the main flow path opposite to the first trap wall, and is formed between the main flow path side wall on the second trap wall formation side and the case. 4. The dust trap device according to claim 3, wherein a gap is formed in the dust trap. 5. A third trap upstream of the second trap wall for capturing dust in an air flow between the second trap wall and the case.
The dust trap device according to claim 3, wherein the trap wall is formed to project in the same direction as the second trap wall. 6. The dust according to claim 5, wherein a gap is formed between the second trap wall and the base end side of the third trap wall, and the gap communicates with the dust flow path. Trap device. 7. The air flow path is provided up and down, and the case is provided with a dust receiving portion for receiving dust falling from a trap wall. The dust trap device according to any one of the above. 8. The rectifying section is provided in the main flow path, and the rectifying section is provided with an air flow detecting sensor for detecting an air flow of the air flow. The dust trap device according to any one of the above.