JPH0957026A - Composite felt and bag filter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide felt and a bag filter excellent in the strength of cloth, dry heat shrinkage and creep rate at high temp., dust collecting efficiency and dust removability by brushing. SOLUTION: Woven base cloth made of spun polyphenylene sulfide yarn and a web of polyphenylene sulfide fibers are intertwisted to obtain the objective composite felt. This felt is sewed in a bag shape to obtain the objective bag filter.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention has a high fabric strength,
The present invention relates to an excellent composite felt having a low dry heat shrinkage and creep rate at high temperature and a bag filter made of the same.

[0002]

2. Description of the Related Art As a filter cloth used for a bag filter for high-temperature exhaust gas attached to an incinerator for municipal solid waste, a cloth made of a fiber having excellent heat resistance and chemical resistance as the exhaust gas at high temperature is used as a filter cloth. The one made by sewing the felt into a bag is generally used. As a fiber having excellent heat resistance and chemical resistance, polyphenylene sulfide fiber, aramid fiber, polytetrafluoroethylene fiber, polyimide fiber, polytetrafluoroethylene fiber mixed with glass fiber is used. In recent years, the proportion of felt used as a filter cloth for bag filters has been increasing. This is because the degree of freedom in setting the porosity and surface pore size, which influences dust collection efficiency and dust removal performance, is greater than that of fabrics. Because it is expensive.

The filter cloth for bag filters has good dust collection efficiency, good dimensional stability at high temperatures, that is, low dry heat shrinkage rate and creep rate, and dust removal property. It is required to be good. In particular, the dimensional stability at high temperature is required to be good because it greatly affects the performance and durability of the bag filter. For example, when a felt having a high shrinkage rate at a high temperature is used, the felt comes into close contact with the retainer due to shrinkage during use, so that the felt may be damaged and dust may leak when repeatedly wiped off. When a felt having a high creep rate at a high temperature is used, the felt stretches and loosens during use, so that the felt may be damaged and dust may leak when repeatedly brushed off.

The felt, which is generally used as a filter cloth for bag filters, is made by using a woven base cloth for increasing the strength, laminating the webs on both surfaces of the woven base cloth, and entwining them with a needle punch. The increase in dust collection efficiency, the reduction in dry heat shrinkage and the reduction in creep rate can be achieved by increasing the puncture density and the entanglement of the web to make the felt structure dense.

In order to improve the dimensional stability of the felt,
Japanese Unexamined Patent Publication (Kokai) No. 5-317620 proposes a polyphenylene sulfide felt based on a woven fabric of polyphenylene sulfide filaments having a dry heat shrinkage rate of 180 ° C. and a weaving density.

[0006]

However, since such a conventional proposal uses a filament woven fabric as the base fabric, when the needle density is increased, the base fabric is cut due to needling, and the strength of the felt is reduced. There was a problem. The temperature of the incineration exhaust gas acting on the bag filter using the filter made of polyphenylene sulfide fiber is about 170 to 190 ° C in consideration of the heat-resistant temperature of the polyphenylene sulfide fiber, but in the actual operation, it is temporarily It may rise up to about 230 ℃,
A felt having good dimensional stability at higher temperatures has been demanded.

Further, if the dust-removing property of the felt is inferior, the pressure loss of the bag filter rises at an early stage and the effective life of the filter cloth is shortened. Therefore, a felt having a better dust-removing property is required. It was

[0008] In view of the drawbacks of the prior art, the present invention provides
A composite felt suitable for use as a bag filter used at high temperatures, having high fabric strength, low dry heat shrinkage and creep rate at high temperatures, and excellent dust collection efficiency and dust removal properties, and a bag filter made of the same. Is intended to be provided.

[0009]

In order to solve the problems of the prior art, the present invention adopts the following means. That is, the composite felt of the present invention is characterized in that a woven textile fabric made of polyphenylene sulfide spun yarn and a web of polyphenylene sulfide fiber are entangled, and the bag filter of the present invention is such a composite felt. Is sewn into a bag shape.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention seeks a felt which has high strength at high temperature, low dry heat shrinkage and creep rate at high temperature, and excellent dust collection efficiency and dust removal property, and With such a felt, the inventors have earnestly studied to provide a filter cloth for a bag filter, which maintains the above-mentioned characteristics even at a high temperature of 230 ° C., has excellent morphological stability, and has stable filter characteristics. As a result, it was clarified that all the above functions are satisfied by constructing a composite felt by using a woven fabric made of spun yarn made of polyphenylene sulfide fiber as a base fabric.

The polyphenylene sulfide fiber referred to in the present invention is a fiber which is known to have excellent chemical resistance and heat resistance, and 90% by mole or more of the constitutional unit of the fiber is-(C6 It is composed of a polymer composed of H4 --S) n-.

In order to improve the dimensional stability at high temperature for the purpose of preventing damage during use of the composite felt (hereinafter referred to simply as "felt") and the bag filter, the temperature of the incineration exhaust gas that acts on it rises up to about 230 ° C. In consideration of this, it is preferable that the 230 ° C. dry heat shrinkage rate of the felt is 5% or less and the 230 ° C. creep rate is 2% or less.
It is more preferable that the creep rate at ° C be 1% or less. To increase the dimensional stability, the method of increasing the needle density of the felt is usually used, but as a result of diligent study to solve the decrease in the composite felt strength due to the increase of the needle density described above, polyphenylene was used as the felt base cloth. By using a spun yarn fabric made of sulfide short fibers,
It has been found that it is possible to increase the entanglement of the web to make the felt dense and to increase the dimensional stability at high temperature without the reduction in strength that occurs in the felt using the filament woven fabric, which has been a problem in the past. As a result, it is possible to obtain a felt which is suitable as a bag filter and has high strength and excellent dimensional stability at high temperatures. It is not clear why the reduction in strength is reduced by using the spun yarn fabric as the base fabric, but when the filament is cut into single yarns by needling, the tenacity decreases accordingly, whereas in the spun yarn, It is considered that even if some single yarn cutting occurs, if it is a fluffy short fiber or the like on the yarn surface, it will not be strongly involved. It is also considered that the fluffy short fibers on the yarn surface of the spun yarn are entangled with the web by needling, whereby the felt becomes dense and the dry heat shrinkage rate and the creep rate of the felt are improved. The felt of the present invention is needle-punched with a needle density of 250 to 400 needles / cm ² . In the present invention, a woven fabric woven from polyphenylene sulfide spun yarn is used as the felt base fabric, whereby a felt having high strength and excellent dimensional stability under high temperature can be obtained.

Further, in order to improve the dust collection efficiency, it is sufficient to make the felt dense, and for that purpose, a method of increasing the needle insertion density is preferable. Further, it is preferable that at least a part of the fibers on the surface is welded by subjecting the felt surface to a burning treatment with a burner flame or an infrared heater, and then pressing with a hot roll, since the dust removal property becomes good.

That is, since the felt of the present invention uses the polyphenylene sulfide spun yarn woven fabric as the base fabric, it is possible to make the felt dense without lowering the strength, and not only the fabric strength but also the dimensional stability and dust. The collection efficiency of is improved. Further, by welding a part of the fibers on the surface, the surface is filtered, and the permeation of dust into the inside of the felt is reduced, so that a good dust removal property can be obtained. Further, by forming the felt of the present invention into a bag shape, it becomes possible to obtain a filter that can be used for a longer period of time.

The single fiber fineness and fiber length of the polyphenylene sulfide spun yarn used for the felt base fabric are not particularly limited. Also, the strength of the base cloth is preferably 30 kg / 5 cm or more for both warp and weft, 50 kg
More preferably, it is / 5 cm or more. If the strength of the base fabric is less than 30 kg / 5 cm, it is not preferable because when it is used as a filter, it is likely to cause a leak from a defective portion and easily cause felt damage due to continuous use at high temperature. As such a woven fabric, for example, a spun yarn of 20/2 is preferably used, and it is preferable that the weave density is 15 yarns / inch or more for both the warp yarn and the weft yarn from the viewpoint of the strength of the felt and the shape retention of the base fabric.

Further, when forming a bag filter from such a felt, by sewing with a filament thread made of polyphenylene sulfide fiber or a sewing thread made of spun yarn, the object and effect of the present invention can be achieved more reliably. Therefore, it is preferable.

[0017]

The present invention will be described below with reference to examples. The tensile strength, dry heat shrinkage, and creep rate of the base cloth and felt were measured by the following methods.

(Tensile strength) Using a Tensilon tensile tester, sample width 5 cm, gripping interval 10 cm, tensile speed 10
Measured in cm / min. This was performed three times, and the average was calculated.

In the SS curve of the felt, a point at which the base cloth breaks and a point at which the web breaks appear, and the point at which the base cloth breaks is defined as the felt strength.

(Dry heat shrinkage ratio) A sample having a size of 40 cm × 40 cm was used, and both the warp and the weft were accurately marked at intervals of 20 cm. This sample was placed flat in a dryer and heat-treated at 230 ° C. for 180 minutes. The mark interval of the sample taken out was measured, and the dry heat shrinkage ratio was calculated by the following formula. This was performed three times, and the average was calculated.

Dry heat shrinkage (%) = (L−L ′) / L × 100 where L = length before heat treatment (cm), L ′ = length after heat treatment
(cm) (creep rate) A sample having a width of 5 cm and a length of 30 cm was used, and marks were made at exactly 20 cm intervals in the longitudinal direction. A load of 1 pound was applied to this sample, which was hung in a dryer and heat-treated at 230 ° C. for 180 minutes. The mark interval of the sample taken out was measured, and the creep rate was calculated by the following formula. This was performed three times, and the average was calculated.

Creep rate (%) = (L′−L) / L × 100 where L = length before heat treatment (cm), L ′ = length after heat treatment
(cm) (Collection efficiency) JIS 10 type dust is used, dust concentration is 1
Pressure loss of 50 mmA at 4 g / m ³ and filtered wind speed of 2 m / min.
Filtration was performed until q increased, and the collection efficiency was obtained from the amount of dust supplied and the amount of dust that passed through the felt.

(Dust removal property) Using JIS Class 10 dust, dust concentration 33 g / m ³ , filtration wind speed 1.5 m
The dust is blown off by performing a filtration at a speed of 1 / min and injecting compressed air having a pressure of 6 kg / cm ² for 0.1 sec when the pressure loss reaches 150 mmAq. This was repeated 200 times, and evaluation was performed by the pressure loss before filtration and the pressure loss after 200 times of brushing off.

Example 1 Polyphenylene sulfide short fibers having a fineness of 2 d, a cut length of 51 mm and a crimping number of 14 co / inch were used, and a single yarn count of 20 was used.
s, two spun yarns were obtained. This was plain woven to obtain a polyphenylene sulfide spun yarn woven fabric. Then, heat setting was performed at 220 ° C. for 45 seconds while applying overfeed to obtain a base fabric having a warp density of 26 yarns / inch and a weft yarn density of 18 yarns / inch. The tensile strength of this base fabric is shown in Table 1. A web made of polyphenylene sulfide short fibers having a single yarn of 2 d, a cut length of 51 mm, and a crimping number of 14 co / inch is laminated on both sides of this base fabric, and a basis weight of 550 g / m ² ,
A needle felt having a puncture density of 300 needles / cm ² was obtained. Further, the felt was subjected to quill treatment with a burner flame and then pressed with a hot roll to weld a part of the fibers on the felt surface. Table 1 shows the tensile strength, dry heat shrinkage rate, creep rate, collection efficiency, and dust removal property of this felt.

Comparative Example 1 A polyphenylene sulfide filament woven fabric was obtained by using a polyphenylene sulfide filament having a single yarn fineness of 4d and a filament number of 100 as a plain weave. 220 ° C
Was heat set for 45 seconds while giving an overfeed to prepare a base fabric having a warp density of 26 yarns / inch and a weft yarn density of 26 yarns / inch. The tensile strength of this base fabric is shown in Table 1.

On this base cloth, single yarns 2d, similar to the embodiment,
A web made of polyphenylene sulfide fiber with a cut length of 51 mm and a crimping number of 14 co / inch is laminated to give a basis weight of 55.
A needle felt having a needle density of 0 / m ² and a needle density of 300 needles / cm ² was obtained. Table 1 shows the tensile strength, dry heat shrinkage ratio, creep ratio, collection efficiency, and dust removal property of this felt.

[0027]

[Table 1] As is clear from Table 1, the felt made of the polyphenylene sulfide spun yarn woven fabric of the present invention as the base fabric has a smaller dry heat shrinkage and creep rate at 230 ° C than the felt made of the polyphenylene sulfide filament woven fabric as the base fabric. It has excellent dimensional stability and strength. Furthermore, it is also excellent in collection efficiency. In addition, the felt of the present invention has a very good dust-dispelling property as compared with the comparative example because some of the fibers on the surface are welded.

Further, the felt of the example was formed into a bag shape by a usual method and used as a bag filter in a refuse incinerator at a working temperature of 190 ° C. After 12 months, the product was taken out and checked, and it was in a good condition without any adhesion or looseness between the retainer and the filter cloth.

[0029]

According to the felt of the present invention, the dry heat shrinkage and creep rate at high temperature are small, and the dimensional stability,
It is possible to easily provide a bag filter having excellent fabric strength, excellent dust collection efficiency, and excellent dust removal property.

Claims (11)

[Claims] 1. A composite felt comprising a woven fabric base made of spun yarn of polyphenylene sulfide and a web of polyphenylene sulfide fibers entangled with each other. 2. The composite felt according to claim 1, wherein the base fabric is a woven fabric having a tensile strength of 30 kg / 5 cm or more in both warp and weft. 3. The tensile strength of the base cloth is 50 k in both warp and weft.
The composite felt according to claim 1, which is g / 5 cm or more. 4. The composite felt according to claim 1, wherein the dry heat shrinkage of the base cloth at 230 ° C. is 5% or less. 5. The composite felt according to claim 1, wherein the dry heat shrinkage of the base cloth at 230 ° C. is 2% or less. 6. The composite felt according to claim 1, wherein the base fabric has a creep rate of 230 ° C. of 3% or less. 7. The composite felt according to claim 1, wherein the 230 ° C. creep rate of the base fabric is 1% or less. 8. The composite felt has a puncture density of 250 to 40.
The composite felt according to claim 1, which has been punched at 0 bars / cm ² . 9. The composite felt according to claim 1, wherein at least some of the fibers on the surface of the composite felt are welded. 10. The composite felt according to claim 1, wherein the surface of the composite felt is subjected to quilling treatment and roll treatment. 11. A bag filter comprising the composite felt according to claim 1 sewn in a bag shape.