JPS6029534B2 - Bag filter cleaning device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a bag filter cleaning device used to separate solid waste or recovered materials suspended in a gas stream from the gas. .

A bag filter device generally introduces waste material or recovered material (hereinafter referred to as recovered material) into a cylindrical bag filter with a bottom made of porous material, and discharges the collected gas from the exit of the bag filter. When the gas passes through the bag filter, the recovered material adheres to the bag filter and is separated from the gas.

However, in this device, the recovered substances attached to the filter accumulate and impede the gas permeability of the filter.
A means is required to clean the filter by removing the adhering collected substances from the filter. As cleaning means, two methods have been proposed: one in which the bag filter is shaken mechanically, and the other is a so-called backflow method in which the normal gas flow direction is briefly reversed by feeding compressed air into the bag filter. However, the latter backflow method is superior in terms of uniformity of cleaning performance, simplicity of the device, and durability of the bag filter.

In general, a bag filter device equipped with this backflow type cleaning device has a cylindrical member attached to the entrance end of a bottomed cylindrical bag filter made of fabric etc. A compressed air source and a suitable compressed air jetting nozzle are installed along the line, and compressed air is fed into the bag filter from the jetting nozzle to generate an airflow from inside the bag filter in the opposite direction to the normal gas flow. Let it act on
It is configured to remove collected substances adhering to the outside of the filter.

The present invention relates to this backflow type bag filter cleaning device, and its purpose is to improve the bag filter cleaning efficiency of compressed air. The above objective is achieved by generating the maximum amount of reversed air flow with the compressed air supply amount. FIG. 1 shows an example of a bag filter device equipped with the cleaning device of the present invention.

The interior of the housing 1 is divided by a partition wall 11 into a filter chamber 12 having an inlet 121 for gas containing recovered substances, and an exhaust chamber 13 having an outlet 131 for discharging filtered gas. A cylindrical member 3 is connected to the upper entrance end of the bag filter 2, and the cylindrical member 3 is airtightly connected to the partition wall 1.
1 , the bag filter 2 is located within the sieving chamber 12 , and the funnel-shaped closing portion 31 of the cylindrical member 3 is located within the exhaust chamber 13 . The bag filter 2 is made of a cloth band, and is maintained in a cylindrical shape by being fixed to steel wire rings 21, 21, . is secured to the lower part of the sieve chamber 12 via a spring 22. A jet nozzle 42 for jetting compressed air is formed in the cylindrical member 3 located in the exhaust chamber 13.

That is, a nozzle member 4 is crowned and connected to the upper end of the cylindrical member 3, and an annular air reservoir 41 is formed between the nozzle member 4 and the inner circumferential surface of the cylindrical member entrance portion 31, and an annular air reservoir 41 is connected thereto. An annular compressed air jet nozzle 42 that closes toward the inside of the bag filter 2 is formed. A closing opening 35 is formed in the center of the cylindrical member 4 to open the inside of the cylindrical member 3 and the exhaust chamber. The ejection nozzle 42 has a constricted part 421 formed in the middle part, and has a shape that extends to the neck opening 422. By making the ejection nozzle 42 into a constricted and expanding shape in this way, the compressed air expands from the constricted part 421 to the dawn opening 422, and the pressure decreases but the speed increases, making it possible to inject compressed air at supersonic speed. shall be. The air reservoir chamber 41 is connected to a compressed air supply source 53 via a solenoid valve 52 via a piping 51.
Compressed air is supplied through a path independent of the opening 35, forming a bag filter cleaning device. FIG. 2 shows another embodiment of the bag filler cleaning device of the present invention.

The upper part of the cylindrical member 30 connected to the entrance end of the bag filter 2 and located in the exhaust chamber 13 is opened in a funnel shape, and a lid 43 is crowned on the end surface of the cylindrical member 30, and a lid 43 is inserted through the lid 43. A compressed air jet nozzle 44 is arranged at the axial center of the joint member 30. The jet nozzle 44 is formed with a constricted portion 441 and has a widened constricted shape with a wide circle 442. The jet nozzle 44 is connected to a compressed air source via a solenoid valve via piping (not shown), as in the above embodiment. Note that 11 is a partition wall in the housing, and 35 is a gate that fits into the exhaust chamber. When a recovered substance in a gas is separated using the apparatus shown in FIG. The gas inside the filter 2 is led out from the central opening of the nozzle member 4, and is suctioned and discharged from the exhaust port 131 by an exhaust fan (not shown) along the path indicated by the solid arrow in the figure.

The recovered material is separated from the gas as it passes through the bag filter 2. A portion of the separated recovered material is transferred to the monkey chamber 1.
Most of the particles fall to the bottom of the filter 2, but most of them adhere to the filter 2 and accumulate on the filter surface as the work continues. Therefore, the compressed air is controlled by the electromagnetic valve 52 to feed the compressed air for a minute time at predetermined time intervals, and is injected into the bag filter 2 from the jet nozzle 42. As a result, air sucked by the jet is introduced into the bag filter 2 in addition to the injected compressed air, and the normal gas flow is reversed in the direction of the broken line arrow shown in the figure, and the action of this reversed air flow causes the bag to be removed. The collected substances deposited on the filter 2 are removed. In this case, the present invention has the jet nozzle constricted and expanded so that compressed air can be jetted out at supersonic speed, thereby achieving a large bag filter cleaning effect by supplying a relatively small amount of compressed air as described later. It can be forced. With the aim of improving the cleaning efficiency of bag filters using compressed air, the inventors measured the pressure applied inside the bag filter and the acceleration of deformation of the bag filter when compressed air jets were activated, and also used a high-speed camera. As a result of observing the situation in which recovered substances were released from the surface of the bag filter, it was found that when compressed air was injected into the bag filter, the bag filter expanded in a drum shape between the rings arranged around its outer periphery and adhered to the surface. It was observed that the recovered material moved with the bag filter due to the acceleration of the bag filter, and separated from the bag filter due to inertia at the point of maximum expansion of the bag filter.

Therefore, it was found that the greater the pressure and acceleration inside the bag filter when compressed air is injected, the better the cleaning effect is, and furthermore, the greater the pressure inside the bag filter is as the compressed air flow rate and the suction flow rate sucked by it are greater. Ta. Figure 3 shows the measurement results, showing the total flow rate of reversed airflow in the bag filter GT (GT=G^+GB, G^: compressed air flow rate,
The pressure inside the bag filter increases as the GB (suction flow rate) increases. The acceleration also increases. In this case, during the total flow rate GT, the compressed air flow rate G^ of the suction flow rate GB
The ratio GB/G^ is extremely large, and the total flow rate G
As T increases, in other words as the pressure inside the bag filter increases, G8/G^ increases. Therefore, it can be seen that in order to enhance the cleaning effect of the bag filter, it is important to increase the suction flow rate GB. In addition, the above measurement was performed using a compressed air pressure of 6k9/ground, and the pressure P and acceleration Q' were measured at the lowest part of the bag filter. FIG. 4 shows a conventional example of the above-mentioned backflow type bag filter cleaning device. A nozzle member 45 is connected to the upper end of a cylindrical member 35 that is connected to the exit end of the bag filter and located in the exhaust chamber, and a nozzle member 45 is connected to the upper end of the cylindrical member 35 . An annular jet nozzle 46 is formed which is compatible with an air supply source. The nozzle 46 is a normal jet nozzle whose cross-sectional area becomes narrower in the opening direction. In such an ejection nozzle, the ejection speed from the counterfeit port is at most the sonic speed even if the compressed air pressure and compressed air flow rate are increased, and the suction speed sucked by the current at this time is also at the sonic speed at the maximum. FIG. 5 shows a comparison of the suction flow rate when compressed air is injected at sonic speed and when compressed air is injected at supersonic speed according to the present invention.

The device of the present invention used was of the type shown in FIG. 1, and the flow path area (Ao) of the ejection nozzle constriction portion 421 and the area ratio of the counterfeit opening 422 were set to A/Ao = 1.34. Supply compressed air pressure Po and air pressure P of the nozzle 422. and P
, /Po=0.2, and the ejection speed was set at 1.7 Mach. As shown in Figure 5, when the injection speed is sonic speed and when it is supersonic speed (1.7 Mach), the total flow rate G of the reverse airflow is
When T and the resulting pressure P in the bag filter are the same, the compressed air flow rate G in G is about 10% smaller in the case of 1.7 Mach. In other words, GB/G
^ is about 10% higher in the case of 1.7 Mach. That is, in order to achieve the same cleaning effect, injection at supersonic speed requires less compressed air to be fed than injection at sonic speed, resulting in a corresponding reduction in power. Furthermore, when compressed air is fed at the same flow rate, the acceleration is greater when the air is injected at supersonic speed than when it is injected at the sonic speed, resulting in a superior bag filter cleaning effect. As described above, the present invention is a backflow type bag filter cleaning device in which the compressed air jet nozzle is shaped into a constricted and expanding shape to inject compressed air into the bag filter at supersonic speed, thereby improving suction efficiency. (GB/G^), improves the cleaning efficiency of the bag filter, and contributes to saving power.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a bag filter device equipped with the cleaning device of the present invention, FIG. 2 is a sectional view of another embodiment of the cleaning device of the present invention, and FIG. 3 is a sectional view of the interior of the bag filter during the bag filter cleaning action. Diagram showing the relationship between pressure and reverse air flow rate,
FIG. 4 is a sectional view showing an example of a conventional cleaning device, and FIG. 5 is a diagram showing the relationship between compressed air injection speed and reverse air flow rate during bag filling and cleaning operations. 1...Housing, 12...Sarugoshitsu,
13... Exhaust chamber, 2... Bag filter, 3, 30, 35... Cylindrical member attached to the bag filter, 42, 44, 46... Compressed air ejection nozzle, 421, 441...Constriction part of the ejection nozzle, 422,442...Earth opening of the ejection nozzle. Figure 1 Figure 2 Figure 3 Figure 5 Figure 4

Claims (1)

[Claims] 1. A bottomed cylindrical baggage filter is placed in the filtration chamber of the housing, which is divided into a filtration chamber for introducing gas containing recovered solid substances and an exhaust chamber for discharging the filtered gas, and an open end of the baggage filter is installed. In a bag filter device comprising a cylindrical member connected to the exhaust chamber, the end of the cylindrical member on the filtration chamber side, which passes through a partition wall that partitions the filtration chamber and the exhaust chamber, is connected to the opening of the bag filter. At the same time, an opening is formed at the end on the exhaust chamber side to communicate the inside of the cylindrical member and the exhaust chamber, and an ejection nozzle is provided in the cylindrical member with its ejection port facing the bug filter. communicates with a compressed air source through a path independent of the opening, and the jetting nozzle is provided with a constriction part and the jetting port is expanded to jet compressed air into the baggage filter using ultrasonic waves. A bag filter cleaning device characterized by the following.