JPH0663327A - Filter backwashing device in powder recovery device - Google Patents

Abstract

PURPOSE:To provide a filter backwashing device having high backwashing efficiency by limiting the pressure drop across a filter to an extremely low value over a long time. CONSTITUTION:In backwashing work, a suction pass 18 of a suction fan 17 is intercepted by a stop damper 22 not to weaken compressed air jetted from a backwash nozzle 19 by sucked air. And in normal operation, a venturi tube 20 is moved to a position far from an opening of a filter 12, causing an obstacle to the passage of sucked air due to the venturi tube 20 to be prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a filter backwashing device in a powder collecting device which can be used for collecting excess powder in a powder coating device or for collecting various dusts.

[0002]

2. Description of the Related Art In a filter-type powder recovery apparatus, the pressure loss increases as the dust layer collected by the filter becomes thicker, so it is necessary to remove adhered dust at appropriate time intervals.

[0003] Conventionally, as a device for removing dust adhering to a filter, that is, a backwashing device for a filter, it is directed toward the filter from the direction opposite to the filtration direction, and compressed air is sequentially ejected from the backwashing nozzle at regular intervals. Some are designed to scavenge dust.

[0004]

By the way, the work of removing the attached dust is usually performed while the powder recovery apparatus is in operation, that is, while the suction blower of the filter is being driven.

Therefore, conventionally, the compressed air ejected from the backwash nozzle for removing the adhered dust is weakened by the air flow sucked from the outer surface of the filter toward the inner surface thereof. effect,
That is, there was a problem that the backwashing effect was halved.

In order to maximize the effect of the compressed air ejected from the backwash nozzle, the operation of the suction blower is stopped, and the air is sucked from the outer surface of the filter toward the inner surface of the backwash nozzle. Make sure that the compressed air is not weakened. However, even if the operation of the suction blower is stopped, the fan of the suction blower does not stop immediately and rotates for a long time due to inertia, so that the air flow sucked from the outer surface to the inner surface of the filter does not immediately weaken. Therefore, when waiting for the air flow to weaken, it is necessary to suspend the operation of the powder recovery device for a long time every time the adhered dust is removed, so as a practical problem, stop the operation of the suction blower. It is not possible to perform the work of removing adhered dust.

In many cases, the conventional powder collecting apparatus is provided with a plurality of filter units, and the plurality of filter units are sucked by one suction blower. Then, in the case of such an apparatus, the work of removing the attached dust is not performed at once for the plurality of filter units, but is performed one by one in order. Therefore, the suction blower must always be in the operating state, and as described above, it is not possible to stop the suction blower during the work of removing the attached dust.

Next, when the compressed air jetted from the backwash nozzle is supplied to the opening of the filter, the compressed air supplied to the inside of the filter is amplified so that the flow velocity of the compressed air is amplified. Is fitted with a Venturi tube.

However, even during the powder collecting operation, that is, during the suction operation, the clean air that has passed through the filter passes through the venturi tube having a small diameter at its central portion and is discharged to the suction passage by the suction blower. Therefore, the Venturi tube causes a pressure loss. For this reason, conventionally, the suction blower must be increased in size by the amount of pressure loss due to the Venturi tube. When the suction blower becomes large, there is a problem that the equipment cost increases and the noise also increases.

Therefore, according to the present invention, first of all, during the work of removing dust adhering to the outer surface of the filter, that is, during the backwashing work, the suction blower is not stopped and the operation is continued. , Even if the compressed air is ejected from the backwash nozzle, the compressed air from the backwash nozzle is not weakened. Secondly, during the powder recovery work, that is, the suction work, suction is performed by the Venturi tube. An object of the present invention is to provide a filter backwashing device that can suppress the pressure loss of the filter to an extremely low value for a long time by preventing the blower from receiving the pressure loss.

[0011]

In order to solve the above first problem, the present invention provides a backwash chamber between the opening of the filter and the suction passage of the suction blower, and the backwash chamber is provided in the backwash chamber. A backwash nozzle for ejecting compressed air toward the opening of the filter is provided, and an opening / closing damper is provided in the suction passage.

The backwash chamber may be provided with an opening / closing damper for inflowing into the atmosphere.

Next, in order to solve the above second problem,
The present invention can be moved to a position where the air flow passage is formed between the suction passage and the opening of the filter which is located at the opening of the filter during the backwashing work and which is separated from the opening of the filter during the suctioning work. The Venturi tube was installed in the backwash chamber.

Further, in a state in which the venturi tube is located at the opening of the filter, the opening / closing damper of the suction passage is closed and the opening / closing damper for inflowing air is opened, and the venturi tube is located at a position away from the opening of the filter. In this state, even if the movement of the venturi pipe and the opening / closing operations of the suction passage opening / closing damper and the atmosphere inflow opening / closing damper are linked so that the suction passage opening / closing damper opens and the atmosphere inflow opening / closing damper closes. Good.

[0015]

When the opening / closing damper of the suction passage is closed during the backwashing work, the air flow sucked from the outer surface to the inner surface of the filter is shut off. Therefore, the compressed air ejected from the backwash nozzle is not weakened, the compressed air vigorously passes through the filter from the inner surface to the outer surface of the filter, and the adhering dust is effectively scraped off.

Further, during the backwashing operation, if the opening and closing damper for inflowing air into the backwashing chamber is opened to allow the air to flow in, the backwashing chamber does not become a negative pressure, and sufficient air flows from the inner surface to the outer surface of the filter. Is supplied.

Next, at the time of backwashing, the venturi tube is positioned at the opening of the filter, the opening / closing damper of the suction passage is closed, and the opening / closing damper for the inflow of air is kept open. The compressed air ejected from the backwash nozzle draws in a large amount of air that flows into the backwash chamber from the opening / closing damper for the inflow of air through the venturi pipe in the state where there is no air flow sucked toward the filter from the inner surface. Passes vigorously toward the outer surface, and dust adhering to the outer surface of the filter is scraped off.

On the other hand, during normal operation, that is, during suction work,
The venturi tube is separated from the opening of the filter to form an air flow passage between the opening of the filter and the suction passage,
When the opening / closing damper of the suction passage is opened and the opening / closing damper for the air inflow is closed, the air flow sucked from the outer surface to the inner surface of the filter does not pass through the Venturi tube and flows in the backwash chamber. Since it passes through the passage and flows into the suction passage, there is no compression loss due to the Venturi tube during the suction work.

[0019]

Embodiments of the filter backwashing apparatus according to the present invention will be described below.

FIG. 1 shows a first embodiment of the present invention.

In this embodiment, the filter 1 is divided into two parts, left and right.
There are rows. A backwash chamber 2 is provided above the opening at the upper end of each filter 1.

The backwash chamber 2 has a filter 1 on the bottom wall.
The air inlets 3 in which the
The air outlets 4 are formed in the side walls facing each other. The filter 1 is detachably attached to the bottom wall of the backwash chamber 2 by a quick-action joint 5. The air outlets 4 of the left and right backwash chambers 2 are provided with a suction passage 7 in which a suction blower 6 is installed.
Connected by.

The filter 1 is attached to the upper wall of the backwash chamber 2.
The backwashing nozzle 8 that ejects the compressed air toward the opening is installed. From this backwash nozzle 8, filter 1
In order to scavenge the adhered dust, the compressed air is discharged at a predetermined interval for 0.1 to 0.5 seconds.
A venturi tube 9 is installed in the opening of the filter 1.

An open / close damper 10 for opening / closing the suction passage 7 is installed at the air outlet 4 of the backwash chamber 2. The opening / closing operation of the opening / closing damper 10 is performed by the cylinder 11 provided on the upper wall of the backwash chamber 2.

The open / close damper 10 is opened during normal operation, that is, during suction work, and is closed during backwash work. In FIG. 1, the opening / closing damper 10 is opened by the left filter 1 to perform suction work, and the opening / closing damper 10 is closed by the right filter 1 to perform backwashing work.

Next, FIG. 2 shows a second embodiment of the present invention.

Also in this embodiment, as in the first embodiment, the filters 12 are provided in two rows on the left and right, and the backwash chambers 13 are provided above the openings at the upper ends of the filters 12.

The backwash chamber 13 is formed with an air inlet 14 on the lower surface of which the filter 12 is installed, and air outlets 15 are formed on opposite side walls of the left and right backwash chambers 13. The filter 12 is detachably attached to the bottom wall of the backwash chamber 13 by a quick-action joint 16. The air outlets 15 of the left and right backwash chambers 13 are connected by a suction passage 18 in which a suction blower 17 is installed.

On the upper wall of the backwash chamber 13, the backwash nozzle 1 for ejecting compressed air toward the opening of the filter 12 is provided.
9 is installed, and compressed air is 0.1 to 0.5 at predetermined intervals.
It is discharged for a second.

In the backwash chamber 13, the Venturi tube 2 is provided.
0 is installed by a cylinder 21 so as to be vertically movable. The Venturi tube 20 is located in the opening of the filter 12 in contact with the air inlet 14 of the backwash chamber 13 when pushed downward by the cylinder 21, and is backwashed when it is pulled upward by the cylinder 21. Apart from the air inlet 14 of the chamber 13, an air passage is formed between the opening of the filter 12 and the air outlet 15 of the backwash chamber 13.

An open / close damper 22 for opening / closing the suction passage 18 is installed at the air outlet 15 of the backwash chamber 13. The opening / closing damper 22 is connected to the Venturi pipe 20, and when the Venturi pipe 20 is pushed downward by the cylinder 21, the suction passage 18 is closed, and when the Venturi pipe 20 is pulled upward, the suction passage 18 is opened. It moves up and down together.

An atmospheric air inlet 23 is formed on the outer side wall of the backwash chamber 13 at a position closer to the upper side. An opening / closing damper 24 is installed at the air inlet 23.
The opening / closing damper 24 for entering the atmosphere is also used for the venturi pipe 2.
0, and when the Venturi tube 20 is pushed downward by the cylinder 21, the atmosphere inlet 23
Open, and when pulled up, it moves up and down in conjunction with the Venturi tube 20 so as to close the atmosphere inlet 23.

During normal operation, that is, when performing suction work with the filter 12, as in the filter 12 on the left side of FIG. 2, the Venturi tube 20 is pulled upward by the cylinder 21 to open and close the suction passage 18 open / close damper 22. To open and close the opening / closing damper 24 of the atmosphere inlet 23. In this way, the suction air passing from the outer surface to the inner surface of the filter 12 does not pass through the Venturi tube 20.

At the time of backwashing, the venturi tube 20 is pushed down by the cylinder 21 like the filter 12 on the right side of FIG. 2, the opening / closing damper 22 of the suction passage 18 is closed, and the atmosphere inlet 23. Opening and closing damper 24
Open, and then press the backwash nozzle 19 to remove compressed air from 0.1 to 0.1.
Blow toward the Venturi tube 20 for 0.5 seconds,
The Venturi tube 20 sucks the surrounding air, and a large amount of air vigorously passes through the filter 12 from the inner surface to the outer surface of the filter 12 to remove the attached dust.

By the way, when the backwashing work is carried out as in the first or second embodiment of the present invention, and when the backwashing work is carried out with the suction blower sucked as usual. And, there is a significant difference in the backwashing effect, and as shown in the graph of FIG. 4, in the case of the first and second embodiments of the present invention, the pressure loss of the filter over a long period of time. Can be suppressed to a low value. In particular,
In the case of the second embodiment, the effect is remarkable.

The experimental conditions in the graph of FIG. 4 are as follows.

Performance of suction blower: 40m ³ / min 200mmAg 3.7KW 220V 60HZ Number of filters: 2 Filtered air volume: 20m ³ / min (1 each) = 40m ^{3 in} total
/ min filtration area: 10 m ^2/1 present = a total 20 m ² filter aperture diameter: 200 mm venturi throat diameter: 100 mm Next, FIG. 3 is a powder having a filter backwash device of the second embodiment The recovery device is the coating booth 2 of the powder coating device.
The example installed in No. 5 is shown.

In this powder coating apparatus, a recovered powder tank 26 is installed below the filter 12, and the recovered powder tank 2
The powder coating material is sent to the coating gun 28 from 6 by the injector 27.

[0039]

As described above, according to the present invention, since the pressure loss of the filter can be suppressed to an extremely low value for a long time, the number of filters can be reduced as compared with the conventional powder collecting apparatus. Can be reduced, and the suction blower can be downsized.

[Brief description of drawings]

FIG. 1 is a schematic view showing a first embodiment of a filter backwashing device according to the present invention.

FIG. 2 is a schematic view showing a second embodiment of the filter backwashing device according to the present invention.

FIG. 3 is a schematic view of a powder coating apparatus equipped with a filter backwashing apparatus according to the present invention.

FIG. 4 is a graph showing a result of an effect confirmation experiment between a conventional example and an example of the present invention.

[Explanation of symbols]

 1, 12 Filter 2, 13 Backwash chamber 3, 14 Air inlet 4, 15 Air outlet 5, 16 High speed joint 6, 17 Suction blower 7, 18 Suction passage 8, 19 Backwash nozzle 9, 20 Venturi tube 10 , 22 Open / close damper 11, 21 Cylinder 23 Large air flow inlet 24 Open / close damper 25 Painting booth 26 Collected powder tank 27 Injector 28 Painting gun

Claims (4)

[Claims] 1. A backwash chamber is provided between the opening of the filter and the suction passage of the suction blower, and a backwash nozzle for ejecting compressed air toward the opening of the filter is provided in the backwash chamber. A filter backwashing device in a powder recovery device, wherein an opening / closing damper is provided in the suction passage. 2. The filter backwashing device in the powder recovery apparatus according to claim 1, wherein the backwashing chamber is provided with an opening / closing damper for inflowing into the atmosphere. 3. A position that is located at the opening of the filter during backwashing, and is located at a position apart from the opening of the filter when an aspiration is performed so that an air flow passage is formed between the opening of the filter and the suction passage. The filter backwashing device in the powder recovery apparatus according to claim 1 or 2, wherein a movable Venturi tube is installed in the backwashing chamber. 4. The venturi tube is located at the opening of the filter, the opening / closing damper of the suction passage is closed, and the opening / closing damper for the inflow of air is opened, so that the venturi tube is located at a position away from the opening of the filter. In this state, the venturi tube is moved so that the opening / closing damper of the suction passage is opened and the opening / closing damper for the air inflow is closed.
The filter backwashing device in the powder recovery apparatus according to claim 3, wherein the opening / closing damper of the suction passage and the opening / closing operation of the opening / closing damper for inflowing to the atmosphere are interlocked with each other.