JPH0446165B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a method and apparatus for collecting dust in a fluid containing dust, and more particularly, to a method and apparatus for collecting dust in a multilayer filter and collecting dust by impingement, inertial dust collection principles. This invention relates to a dusting device.

(Prior Art) Electrostatic precipitators, bag filters, rotochrons, and the like are widely used as dust collection equipment for dust-containing fluids such as dust-containing gases. However, especially
Bag filters and Rotochrons have problems in that they have large pressure losses and consume a large amount of electricity such as induction fans.

Therefore, low pressure loss multilayer filters based on the principles of collision and inertia dust collection are being used. This multilayer filter has a structure as shown in FIG. 6, for example.

That is, the multilayer filter is manufactured by pressing a thin metal plate to form honeycomb-shaped holes 1 as shown in FIG. 6b.
A plurality of mesh filters 1 each having a large number of a are stacked to form a multilayer structure.For example, by stacking the mesh filters 1 in sequentially changing directions by 90 degrees, the gas flow can be controlled. During the passage, the gas flow becomes a swirling flow as it passes through the honeycomb-shaped holes, and dust with a large inertial force repeatedly collides and is collected. The above-mentioned multilayer filter is held upstream by a fixed frame 2 and housed in a casing 3, and each filter 1, 1 is placed in a duct (not shown) through which dust-containing fluid flows.
... are arranged perpendicular to the fluid flow direction.

The spacing between each mesh filter 1 is generally determined based on the characteristics of dust collection efficiency with respect to filter spacing, as shown in FIG. That is, as is clear from Fig. 7, when the filter spacing is narrowed,
Since the gas flow is changed rapidly, the dust collection effect due to inertial force is large, and the dust collection efficiency is also high. However, as the interval between the filters is increased, the change in gas flow becomes weaker, and the dust collection effect rapidly decreases. On the other hand, dust adhering to the filter is removed by a vibration method or a water washing method, but a gap between the filters is also required to allow the dust to fall. Therefore, the holding margin of the multilayer filter is usually set so that the interval between each filter can ensure the minimum gap for dust fall and has a high dust collection efficiency (see Fig. ₇ ).

(Problems to be Solved by the Invention) As mentioned above, multilayer filters have a multilayer structure, and in order to maintain a high dust collection effect, the spacing between the filters is kept somewhat narrow (usually around 1.0 to 1.5 mm). As a result, the dust adhering to the inside of the filter cannot be completely removed and remains in the lower half. If you use it for a long time in this condition,
Dust accumulates in the lower half of the inside of the filter, resulting in deterioration of both collection efficiency and pressure loss.

To explain in more detail, for example, when dust adhering to a filter is removed by vibration, the adhering dust on the outermost surface part is peeled off even with slight vibration;
From the second sheet onwards, they press down on each other, blocking the path for the dust to fall.
The dust cannot be completely removed. Therefore, as dust collection and dust removal (dust removal) are repeated, dust accumulates in the lower half of the inside of the filter.

The dust accumulation in the lower half of the filter as described above partially blocks the gas flow path area during dust collection.
As shown by the relationship between wind speed and dust collection efficiency in the figure,
What was point A (V ₁ , μ ₁ ) at the initial stage changes to point B (V ₂ , μ ₂ ) as the flow velocity increases, resulting in a sharp deterioration of dust collection efficiency.

Furthermore, as the passing wind speed increases (V ₁ → V ₂ ), the pressure loss of the filter itself becomes larger (ΔP ₁ → ΔP ₂ ) than the pressure loss characteristics shown in Figure 9, and the low pressure loss characteristic of this filter is reduced. It will be damaged.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a multilayer filter dust collection and dust removal device that can achieve high dust collection efficiency and can be operated while always maintaining pressure drop and dust collection efficiency in the initial state. be.

(Means for Solving the Problems) In order to solve the above-mentioned problems and achieve the above-mentioned objects, according to the present invention, in a duct through which a fluid containing dust flows, there is provided A mesh-like multilayer filter arranged, a solid frame provided upstream of the filter, and a filter holding means provided downstream of the filter and configured to be movable forward and backward in order to adjust the holding amount of the filter. , and a filter vibrating means for dust removal have been proposed.

The present invention will be explained in more detail based on the drawings.

As shown in FIG. 1, a fluid G1 containing dust such as dust-containing gas passes through a duct (not shown),
The dust is guided to a dust collector section consisting of a multilayer filter 10. When the dust in the dust-containing gas passes through the multilayer filter 10, it is collected by collision and inertial dust collection, and is discharged downstream as clean gas G2.

The multilayer filter 10 includes a plurality of mesh filters 1.
The mesh filter 1 is housed in a filter outer frame 11 in a stacked state. This filter outer frame 11 is attached with a slight gap between it and the outer casing 12, and the vibration spring 1
3, it is normally urged downward, but it is designed to be vibrated by a combined operation with a cam mechanism 14 provided below. This cam mechanism 1
The shaft 14a of No. 4 is driven by a rotary machine 16 fixed to the lower hopper 15. Furthermore, a shock plate 14b is attached to the filter outer frame 11 between the cam 14 and the filter outer frame 11 to prevent the filter outer frame 11 from being worn out due to direct contact.

On the downstream side of the dust collector section, there is a filter holding frame 17 that holds down the multilayer filter 10, and this is connected to an opening/closing arm 18, and has a mechanism that is operated by a cylinder (not shown) located outside the outer casing 12. . By this rotational movement of the opening/closing arm 18, the filter holding frame 17 is moved back and forth along the bottom of the external casing 12, which also serves as a guide (second
Figures a, b). The filter holding frame 17 has a thin plate structure so as not to disturb the uniformity of the gas flow, and is in line contact with the multilayer filter 10.

A dust collection hopper 15 is provided at the bottom of the outer casing 12, and when dust is removed, it collects dust inside and outside the filter and surface dust that falls through the dust discharge hole formed at the bottom of the filter outer frame 11, and closes the dust valve. It is automatically discharged to the outside at 19.

Next, the operation will be explained.

When passing gas, as shown in Fig. 2a, the multilayer filter 10 is held down by the filter holding frame 17, and the distance between each filter 1 is maintained at an average interval of μ ₁ shown in Fig. 7, and dust collection is performed in this state. .

When the multilayer filter 10 is continuously operated in this state, more and more dust adheres to the multilayer filter 10, and when the filter pressure loss becomes large, a step is started to remove the dust 1.

In this step, the gas flow is stopped, the filter holder 17 is slid downstream by the opening/closing arm 18, and the pressure on the multilayer filter 10 is released. When the pressure on the filter 10 is removed, the spacing between the filters is expanded to some extent evenly by the elastic force of the filter itself (FIG. 2b).

When this operation is finished, vertical vibration is applied to the filter outer frame 11 by the lower cam mechanism 14 and the vibration spring 13, and the dust adhering to the filter surface is brushed off, and the internal adhering dust is removed from the expanded filter. The dust passes through the gap and is further discharged from the multilayer filter 10 through a dust discharge hole formed in the lower part of the filter outer frame 11 (FIGS. 3a and 3b).

When the vibration removal by the cam mechanism 14 is completed,
The filter holding frame 18 returns to its original position (the third
In Figure a), the dust collection process is started again, and this process is repeated.

In the illustrated example, a cam type vibrating device is employed, but a hammer type, electromagnetic type, or vibrator type may be used. Alternatively, the same effect can be obtained by repeatedly moving the filter holder back and forth without using a special vibrating device.

Further, the filter presser driving source is not limited to the air cylinder, but may be an electromagnetic or hydraulic type, and in short, any source may be used as long as the filter can be spaced apart when dust is removed.

(Function) As described above, according to the present invention, by making the interval between each filter of the multilayer filter variable during dust collection and dust removal, each filter is held at a narrow interval during dust collection. In addition to obtaining high dust collection efficiency, when removing adhering dust, the interval between each filter is made large to allow the dust to fall freely and prevent the dust from accumulating on the lower half of the filter.

(Example) Dust-containing gas was collected and adhering dust was removed under the following equipment specifications and operating conditions.

(1) Multilayer filter size...500mm×500mm (2) Number of multilayer filters...10 pieces (3) Multilayer filter material...SUS 304 (4) Passing wind speed...0.5m/sec (5) Gas temperature... Room temperature (6) Inlet gas dust content...4.0g/Nm ³ (7) Outlet gas dust content...0.04g/Nm ³ (8) Dust collection efficiency...99% (9) Dust used...Converter Desulfurization dust (true specific gravity 3.5, apparent specific gravity
1.6) (10) Filter holder drive mechanism...Air cylinder (bore diameter 50mm, stroke 20mm)
mm) (11) Vibration device...Cam type (drive motor: 0 to 180 rpm variable speed) The evaluation of the effect of brushing off is based on the degree of recovery of filter pressure loss when a constant amount of gas is flowing (see Figure 4) Fig. 5 shows the effect of brushing off when changing the filter interval.

With the conventional setting filter spacing (range (1.0 to 1.5 mm) in Figure 5), the removal effect was about 80 to 90%, but with the present invention, the filter spacing can be set to 3.0%.
By setting the thickness to 1 mm or more (the range shown in Figure 5), almost 100% removal effect was obtained. Here, the filter spacing generally refers to the spacing between the protruding parts of each filter, but in this example, the front and rear width of the 10 filters when the entire multilayer filter consisting of 10 filters is pushed in and released. The difference is the number of filters (10−
1).

This makes the initial dust collection efficiency 99% (passing wind speed
0.5m/sec) and initial pressure drop of 10mmAq or less.

In addition, in the conventional method, as shown in Fig. 10,
Both dust collection efficiency and pressure drop tended to deteriorate, with dust collection efficiency dropping to 95% and pressure drop rising to 300mmAq.

(Effects of the Invention) As is clear from the above, according to the present invention, high dust collection efficiency can be ensured, and pressure loss and dust collection efficiency can always be maintained at the initial state.

[Brief explanation of the drawing]

FIG. 1 shows a dust collector section of a multilayer filter embodying the present invention, a is a longitudinal cross-sectional view thereof, b is a front view as seen from the downstream side, and FIG. 2 is a dust collector section shown in FIG. 1. is an explanatory diagram showing the operation of
b shows the time of brushing off, FIG. 3 is an explanatory diagram showing the excitation operation of the device shown in FIG. 1, a shows the downward vibration position, b shows the upward vibration position, and FIG. 4 shows the filter pressure. A schematic diagram showing the recovery state due to loss and dust removal, Fig. 5 is a diagram showing the relationship between filter spacing and dust removal effect, Fig. 6 shows a conventional multilayer filter device, and a is a partial cutout of the whole. FIG. 7 is a diagram showing the relationship between filter spacing and dust collection efficiency; FIG. 8 is a diagram showing the relationship between wind speed and dust collection efficiency; FIG. 9 is a diagram showing the relationship between wind speed and pressure loss, and FIG. 10 is a diagram showing the dust collection efficiency and pressure loss situation in the conventional method. 10... Multilayer filter, 11... Filter outer frame, 12... External casing, 13... Vibration spring, 14... Cam mechanism, 15... Lower hopper, 1
6...Rotating machine, 17...Filter presser frame, 18...
...Opening/closing arm, 19...Dust valve.

Claims (1)

[Claims] 1. A mesh multilayer filter disposed in a duct through which dust-containing fluid flows, transverse to the flow direction thereof, a fixed frame provided on the upstream side of this filter, and a fixed frame provided on the downstream side of the filter. What is claimed is: 1. A device for collecting and removing dust from a multilayer filter, comprising: a filter holding means configured to be movable back and forth to adjust the holding amount of the filter; and a filter vibration means for blowing off dust.