JPS6018448B2 - Buzz filter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The following three methods or combinations thereof have been used to remove collected dust in conventional bag fillers.

First, the furnace gas is shut off and a backwash flow is caused to flow, causing the bag tube to deform (collapse) and the dust cake layer adhering to the inside to be peeled off and brushed off.

The second method is to shake the bag tube using a vibration device, and use the local deformation caused by the vibration acceleration to peel off and brush off the dust layer.

The third method is to apply backwash flow in pulses (time) to instantaneously deform the furnace cloth (large amount of deformation).

However, in bag tubes made of glass fiber that are recently used for high-temperature gases (up to about 250°C), the bending strength of the glass fibers is weak, so the third method, which has a strong blowing effect, cannot be used, and the first method and vibration A second method in which the force is weakened, or a combination of the first method and a second method in which short-term or weak vibration force is used, has been used.

By the way, in the plant tested by the present inventor, the first and second methods were used together due to the use of glass fiber furnace cloth, but since the dust was found to be somewhat adhesive, it was difficult to remove the dust. It is not carried out uniformly on the inner surface of the furnace cloth,
The dust cake layer (which helps collect fine particles) falls locally, reducing the pressure drop in that area, and as a result most of the gas blows through that area.

Therefore, as a result, the dust collection efficiency after dusting is drastically reduced, and since the dust is peeled off locally, there are drawbacks such as an immediate increase in pressure loss.

The present invention was proposed in order to eliminate the above-mentioned conventional drawbacks, and it is possible to uniformly remove dust by applying an excitation force to the entire surface of the furnace cloth tube without applying extreme bending or tension. The purpose is to provide bag fill service. An embodiment of the present invention will be explained below with reference to the drawings. Fig. 1 shows a bag filter having a furnace cloth tube 1 according to an embodiment of the present invention, a clean gas chamber 2, and a dust hopper 4 equipped with a dust-containing gas duct 3. A conveying pipe 5 is provided, and a pressure changing device is provided in the clean gas chamber 2 and the dust hopper 4, which alternately change the flow direction of the gas flowing through the conveying pipe 5.

In the embodiment shown in FIG. 1, during normal operation, dust-containing gas passes through the dust-containing gas duct 3, the dust hopper 4, and the furnace cloth tube 1.
It flows into the interior from the bottom to the top, passes through the furnace cloth tube 1 and exits into the clean gas chamber 2, where it is over-collected on the inner surface of the furnace cloth tube 1.

The collected dust remains on the inner surface of the furnace cloth tube 1, and the action of dust removal in this embodiment is performed as follows.
a. Close the inlet and outlet dampers 8 and 9 (installation of the inlet damper 8 is not essential, but it is desirable).

At the same time, the damper 7 of the passage pipe 5 which connects the dust hopper 4 and the clean gas chamber 2 is used as a barrier. b. Activate the operating device 10 when the gas flow stagnates.

The operating device 10 generates reciprocating motion at a required frequency, and its cycle is several hertz to a few hertz. The pressure difference is the amount that causes a volumetric displacement that is sufficient to move the furnace cloth in the perpendicular direction, plus the margin due to compression. Therefore, the amount of change in volume varies depending on the size of the bag filter.
c. The operation time of the operating device 10 is set to several seconds to tens of seconds, which is necessary to shake off the dust on the inner surface of the furnace cloth tube 1.

This varies depending on the dust. d When dust removal is completed, the operating device 10 is stopped, the damper 7 is closed, and after a certain settling time, the inlet and outlet dampers 8 and 9 are opened to return to the normal dust collection process.

Next, the above operation will be further explained in detail based on FIGS. 3 to 5. First, the state of the chamber in which dust is to be removed is that the inlet and outlet dampers 8 and 9 shown in FIG. tube 5
By using the damper 7 as a barrier, the clean gas chamber 2 and the dust hopper 4 are in an airtight state where they are only separated by the diaphragm 11 (FIG. 3). If the diaphragm 11 is pushed out using the operating device 10 in this state, the gas on the side of the general gas chamber 2 will be compressed, and on the other hand, the gas on the side of the dust hopper 4 will be depressurized, so there will be pressure on the inner and outer surfaces of the wave cloth tube 1. A difference is generated, and the gas flows from the clean room 2 side to the dust hopper 4 side via the cotton cloth tube 1 (FIG. 4).

Next, if the frequency 11 is pulled back with the operating device 10, the gas on the dust hopper 4 side will be compressed, contrary to the above, and the monkey cloth tube 1 will be compressed.
The gas flows to the clean gas chamber 2 side through the (FIG. 5).

The difference in pressure between the inner and outer surfaces of the cotton cloth tube 1 caused by these series of operations causes vibration to be applied to the cotton cloth tube 1, making it possible to brush off the dust on the inner surface of the cloth tube 1. As described above, the embodiment shown in FIG. 1 uses the pressure change device 6 which is a combination of the operating device 10 and the diaphragm 11, but the diaphragm 11 may be of a diaphragm type or a piston type as shown in the drawing.

Next, FIG. 2 shows another embodiment of the pressure change device 6, in which the first
In place of the operating device 10 and diaphragm 11 shown in the figure, a pressure source 12 such as pressurized air or pressurized gas and a passage switching device 13 are combined.

In this case, after closing the inlet and outlet dampers 8 and 9 and closing the damper 7, the pressure source 12 pressurizes the switching valve 14.
is swung to apply pressure alternately to the clean gas chamber 2 side and the dust hobber 4 side. Note that 15 in FIG. 2 is an arrow pointing to the exhaust gas or another compartment dust-containing tank. The amount of air or gas flowing into the clean gas chamber 2 and the dust hopper 4 due to pressurization at this time is based on the same volume calculation basis as in the case of FIG. 1 above.

In addition, the side opposite to the pressurized chamber as described above (the dust hopper 4 side in the drawing) passes through the exhaust or bag filter dust-containing gas duct 3, and due to the pressure change caused by the pressure source, the furnace cloth tube surface can be easily moved in the right angle direction. The structure is such that it changes to As explained in detail above, the present invention provides a pressure change that can alternately apply pressure vibrations to the clean gas chamber and the dust hopper by connecting the clean gas chamber and the dust hopper to which the dust-containing gas duct is attached. Since the device is installed, forced gas pressure (or air pressure) can be changed using the same pressure change device.
By applying fluctuations to the surface of the furnace cloth tube, the excitation force necessary for dust removal can be applied to the furnace cloth tube without excessively displacing or locally bending the furnace cloth.

Furthermore, according to the present invention, pressure fluctuations of several Hertz to several tens of Hertz can be uniformly applied to the entire surface of the furnace cloth tube in a direction perpendicular to the furnace cloth surface, so that dust can be uniformly brushed off from the furnace cloth. can. Furthermore, by adjusting the cycle and capacity, it is possible to generate sufficient acceleration on the furnace cloth surface without damaging the furnace cloth, making it possible to leave a thin and uniform amount of residual dust on the furnace cloth. Therefore, highly efficient stagnation dust collection is possible even immediately after dusting off.

[Brief explanation of the drawing]

FIG. 1 is a side sectional view of a bag filter according to an embodiment of the present invention, FIG. 2 is a sectional view showing a pressure change device of a different embodiment from FIG. 1, and FIGS. 3, 4, and 5. 2A and 2B are side sectional views sequentially illustrating the operation sequence of the bag filter shown in FIG. 1. FIG. Explanation of main parts of the figure 1... Furnace tube, 2...
Clean gas chamber, 3...dust-containing gas duct, 4...dust hopper, 5... lotus tube, 6... pressure change device. Figure 1 Figure 2 Figure 3 Figure 4 Figure 5

Claims (1)

[Claims] 1. In a bag filter having a filter cloth tube, a communication pipe is provided that communicates the clean gas chamber with a dust hopper equipped with a dust-containing gas duct, and a clean gas chamber is provided in which the flow direction of the gas flowing through the communication pipe is alternately changed. and a pressure changing device in the duct hopper.