JPS6036806B2 - dust collection filter cloth - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to the structure of a dust collector cloth that can reduce the pressure loss of a bag filter.

Generally, in filter dust collectors, pressure loss increases as dust accumulates in the bag and filter.
A blow-off operation is performed when a certain pressure loss is reached or at regular intervals. In this case, if the increase in pressure loss is small, the blow-off cycle can be increased and the power cost of the fan can be saved, so studies have been conducted on bag filters that can reduce the increase in pressure loss. However, all of the conventional measures taken to reduce the pressure loss of bag filters have been to change the raw yarn or woven fabric structure of the furnace cloth, and all of them have used only natural fibers and/or synthetic fibers. Therefore, it is difficult to reduce the pressure loss, and in particular, it has been considered extremely difficult to reduce the pressure loss without causing a decrease in dust collection efficiency. As a result of various studies on the structure of a furnace cloth that can reduce the pressure loss of the bag filter, the present inventors have found that when mixing metal fibers into the furnace cloth, an appropriate conduction distribution can be achieved over the entire surface of the furnace cloth. The inventors have discovered that a furnace cloth with extremely low pressure loss can be obtained by mixing in the following manner, and have arrived at the present invention. That is, the present invention uses a metal fiber blend yarn in which the length fraction (yarn conduction fraction) a of the conductive portion to the yarn length is 0.4 or less for most of the warp and/or weft, The dust collection furnace cloth is characterized in that the fraction (woven fabric conduction fraction) A of the length of the conductive portion to the length of the yarn in the woven fabric is 0.025SA/0.15.

In the present invention, the metal fiber blended yarn is a blended yarn of metal fibers and synthetic fibers, natural fibers, or inorganic fibers, and the metal fibers include short fibers such as stainless steel, copper, nickel, platinum, aluminum, and tungsten. However, stainless steel fibers made of stainless steel, particularly SUS-314 and SUS-347, are preferably used in terms of strength, corrosion resistance, etc. In the dust collecting furnace cloth of the present invention, most of the metal fiber blended yarns having a yarn conduction fraction a of 0.4 or less are used in the warp and/or all yarns, preferably 90
% or more.

As shown in Fig. 1, the thread conduction fraction a is determined by running the blended yarn 2 in contact with two metal rods 4 and 5, each having a diameter of 3 and a center distance of 1 rib, at a tension of 20 degrees, at an angle of 135 degrees, and at a running speed. Pass at a rate of 2m/min, connect a 1000V super resistance meter between rods 4 and 5, record the conduction distribution, and then add up the lengths of the conductive parts (less than 1mm per 1c). It is something.

At this time, the sample length L is set to low, and the conduction fraction a is the fraction of the total length of the conduction portion L2 to L, that is, La.

The thread conduction fraction can be controlled by changing the cut length of the metal fiber sliver, the metal fiber blending ratio in the blended yarn, and the number of drawings in the spinning process. Generally, the longer the cut length, the greater the mixing ratio, and the greater the number of drawings, the greater the yarn conduction fraction. The woven fabric conduction fraction A is the value obtained by multiplying the fraction of the number of metal fiber blended yarns used x i by the yarn conduction fraction ai for each yarn conduction fraction, and sums it up, that is, A=i≧laiX
It is i.

For example, in a woven fabric where the number of threads per inch is 76 warp threads and 58 weft threads, the thread conduction fraction for the warp threads is 0.10.
A blended yarn of
．． When the blended yarn of No. 05 is implanted on the entire surface, the conductive fraction of the woven fabric is A=o.・ox Makikawa. o5x machine=o. It becomes o78.

The dust collection furnace cloth of the present invention has the above-mentioned woven cloth conduction fraction A of 0.02.
5SA is 0.15, preferably 0.04SA is 0.1.

In the furnace cloth of the present invention, the pressure loss ΔP rises slowly in the early stage of dust collection, that is, in the area where the dust load is small, and the initial low pressure loss characteristic is maintained in a biased form even in the final stage of dust collection.

That is, the air permeability K of the dust layer in a region with a high dust load is almost constant regardless of whether or not the metal fiber blend yarn is mixed, the conductive fraction, and the mixing interval. In addition, since the pressure loss △P has a linear proportional relationship with the furnace overspeed Us, in order to generally express the effect of the present invention, rather than expressing it by the reduction rate of pressure loss, as shown in Fig. 2, Find the relationship between the load m, and the drag force S, and then extrapolate the drag force S to the initial value mr of the dust load (mr=0 in the example),
That is, it is appropriate to express it as the rate of decrease in the projected drag force Sr* (in the example, the drag force S extrapolated to m,=0.*). The furnace cloth of the present invention reduces the above-mentioned projected drag force by 0.3 to 0.0 compared to the conventional furnace cloth, regardless of the particle size, shape, concentration, and furnace overspeed of the dust.
The air permeability of the dust layer can be reduced by 7 times, and the air permeability of the dust layer K
Therefore, the drag force S, and therefore the pressure loss ΔP, can be made extremely small regardless of the dust load m.

To give a more detailed explanation of this, Fig. 3 shows A and S obtained for various types of kiln cloths having the same loom structure but with different mixed forms of metal fiber blended yarn.

This is a graph showing the relationship between *. From this graph, S.
*In order to sufficiently reduce A, it is necessary to set A within an appropriate range. When A exceeds 0.15 or falls below 0.025, the projected drag is equal to that of the conventional furnace cloth (projected drag of 35°
It is not much different from Juntsuba Wani), and the pressure loss is extremely large. The furnace cloth of the present invention is effective in reducing pressure loss as described above, but at the same time it can also reduce the charging property of the furnace cloth to some extent.

In order to further ensure the reduction in chargeability, it is also a preferred embodiment to further mix metal fiber blended yarn with a thread conduction fraction of 0.5 or more into the warp and/or weft of the furnace cloth at intervals of 2 to 5 skins. It is. At this mixing interval, the mixing has little effect on the woven fabric conduction fraction A, but even when this is mixed, A needs to be within the above range. In order to fully realize the effects of the present invention,
The amount of charge on the dust at the dust collector inlet is 0.1 per night.
It is preferable that it is French C or higher. This level of charging occurs almost constantly in normal dust collectors, and the effects of the present invention can generally be fully expressed without any special charging operation. However, in order to ensure the effects of the present invention, charging It is also a preferred mode of use to add the operation upstream of the dust collector. For the same purpose, an electrostatic precipitator can also be used before the filter precipitator. The dust collection furnace cloth of the present invention only uses a metal fiber blend yarn, and there is no need to make any particular changes to the weaving design, so it is possible to reduce pressure loss without reducing dust collection efficiency.

The reduction in pressure loss can reduce fan power costs, and the extension of the blow-off cycle can extend the life of the furnace cloth. Since the dust collecting furnace cloth of the present invention has the excellent features as described above, it can be effectively used in dust collectors in all industries such as steel, chemical industry, ceramic industry, food industry, and pharmaceutical industry.

Example 1 (Examples 1 to 4) Stainless steel fiber sliver with a diameter of 8 mm, average cut length of 50 mm and 9 mm was placed on a cotton paper type polyester stable with a twill degree of 1.5 denier and an average cut length of 5 mm. Blended by a spinning machine, the total blending ratio of stainless steel weave is 0.1, 0.3, and 0.0, respectively.
A 20 count blended yarn containing 5.0.7% was produced.

At this time, the drawing process is carried out twice for blended yarns with a cut length of 5 lengths of stainless fiber, and 4 times for blended yarns with cut lengths of 9 lengths.
Repeatedly. When the yarn conduction fraction a of the two-fold selvedge yarn thus obtained was measured, the values shown in Table 1 were obtained. The reason why the blended yarn was mixed in various forms as shown in columns ■ to ■ of Table 2 is that it is made of satin weave, using two-piece yarn with a warp yarn density of 76 yarns per inch and a weft yarn of 58 yarns per inch. A cylindrical bag/filter with a diameter of 170 mm and an effective length of 90 mm (furnace area of 0.48 mm) is sewn to collect dust by weaving a polyester fabric so that the warp matches the longitudinal direction of the cylinder. Tested with a testing machine. Dust collection test is JIS Z-890
1 Using three types of test dust (poppy seeds and sand), the furnace overspeed Us
= 1.2 m/min, the inlet dust concentration was 17.4 m/N (dust amount: 10 m/min), and 1.5 mountain C/saw-charged dust was collected.

The change in pressure loss is DLPU-0 manufactured by Toyo Baldwin Co., Ltd.
．． 05-170-m-P type differential pressure detector detects the dust load m. The change in pressure drop ΔP was recorded. The drag force s is determined from the pressure loss △P and the Tachibana speed US, and after plotting against the dust load m, the projected drag force S is calculated as shown in Figure 2.

* and the dust permeability K, the dust permeability K is a nearly constant value of 0.0 $ec, and the projected drag force S. * is as shown in column ■ in Table 2. On the other hand, the charged potential of the bag and filter was set at 10c from the center side of the bag and filter.
Place the probe at position m, and use Rion E-14.0.
When measured with a type 1 electrostatic field measuring device, values as shown in column (■) of Table 2 were obtained.

From column ■■ in Table 2, ○
I marked it.

As shown in Table 2, bags and bags made from the hearth cloth of the present invention are shown in Table 2.
In the filter, the pressure loss is significantly reduced and the band position is also reduced to some extent. Example 2 (Example 5
~8) Example 1, No. Furnace fabric having the same structure as 3 to 6, and in which metal fiber blended yarn with a stainless steel blend ratio of 5%, the same cut length on the 50 side, and a thread conductivity of 0.82 is implanted into the warp at intervals of 2.5c. (These were numbered No. 3 to 6 corresponding to Table 2 No. 3 to 6.) Furnace cloths similar to those in Example 1 were sewn, and the same dust collection test was conducted to determine the injection resistance and When the color band position was determined, as shown in Table 3, the projectile drag was found to be No. 2 in Table 2. Similar to No. 3 to No. 6, it has a significantly low value, and the charging potential is also the same as No. 2 in Table 2. The value is even lower than 3-6,
In this case, a furnace cloth with extremely small pressure loss and charge potential was obtained.

Table 1 Table 2 (Note) ○・・・Example ×． ...Reference example Table 3

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a method of measuring yarn conduction fraction,
1 is a burn, 2 is a yarn to be measured, 3 is a tensioner, 4,
5 is a metal rod, and 6 is a winding bobbin. FIG. 2 is a diagram showing the general relationship between dust load m, and drag force S. * is the projective drag force. Figure 3 shows the woven fabric conduction fraction A and the projected drag force S. It is a diagram showing the relationship between *. Tsutomu 7 figure Z figure 3 figure

Claims (1)

[Claims] 1. A metal fiber blended yarn having a ratio of the length of the conductive part to the length of the yarn (yarn conduction fraction) a of 0.4 or less is used in most of the warp and/or weft. The ratio of the length of the conductive part to the length of the thread in the woven fabric (woven fabric conduction fraction)
A dust collecting filter cloth characterized in that A satisfies 0.025≦A≦0.15.