JP6282423B2 - Bag filter for dust collection - Google Patents

Description

TECHNICAL FIELD The present invention relates to a dust collection bag filter that can be regenerated by removing dust with compressed air, and relates to a method for manufacturing a dust collection bag filter that realizes high bondability of a fiber layer constituting the bag filter and low pressure loss. It is.

In a bag filter installed in a dust collector, in order to reduce the maintenance frequency, a regenerative method that blows compressed air continuously on the fiber surface of the bag filter at regular intervals to remove dust collected by the bag filter. There is.

    In this method, since compressed air is continuously blown onto the fiber surface of the bag filter, the bag filter needs to be durable enough to withstand the blowing of the compressed air. In order to increase the durability of the bag filter, it is common to laminate a plurality of filter cloths constituting the bag filter.

    Cited Document 1 describes an invention relating to a filter cloth for a bag filter in which a filter layer and a base material layer having different filling rates in a filter medium fiber are laminated and bonded by thermocompression bonding, thereby improving dust removal and reducing pressure loss. Has been.

Citation 2 describes a bug filter in which a prefilter layer is laminated on a nonwoven fabric layer having a fine filtration surface to prevent clogging of dust into the nonwoven fabric layer.

Cited Document 3 describes a filter material for a bag filter in which a base material layer, a nanofiber layer for collection, and a nanofiber layer for bonding are laminated.

JP2011-147850 JP2012-161790 JP2013-22570

In a bug filter capable of removing dust by compressed air, in Cited Document 1 and Cited Document 2, a fiber layer having a high collection efficiency is laminated on the downstream side of the prefilter layer, and dust having a large particle diameter is prefiltered. A mechanism is described in which dust is collected by a layer, and dust having a small particle diameter is further collected by a subsequent fiber layer having a high collection efficiency. By stacking multiple bag filter filter cloth layers with different dust collection efficiencies, it is possible to collect each particle size for each particle size, preventing clogging of dust into specific bag filter fiber layers, and The life of the bug filter can be extended.

When the filtration layer and the base material layer are thermocompression bonded as described in the specification 0028 of the cited document 1, a calender roll or the like is used on the thermocompression bonding surface while providing a partial non-adhesive portion. They are bonded together.

In Cited Document 3, bonding nanofibers are provided between a dust-collecting nanofiber layer and a substrate layer, and the bonding nanofibers are melted to bond the dust-collecting nanofiber layer and the substrate layer. I am letting. Since the nanofibers having a small fiber diameter are melted and the filter cloth layers are bonded to each other, a sufficient effective filtration area in the bag filter can be secured.

However, in the method of laminating the fiber layers in the bag filter, when the adhesive is applied to the fiber layers, or when the fiber layers to be laminated are melt-treated and thermally bonded, the bonding surfaces of the fiber layers become large. Then, there is a problem that the fibers constituting the bag filter are bonded more than necessary, and the effective filtration area of the bag filter is reduced. On the other hand, if the bonding surface between fibers becomes small, the effective filtration area of the bag filter can be secured, but there is a problem that the fiber layer constituting the bag filter is peeled off by the compressed air blown to the fiber layer. In a fiber laminated bag filter, securing an effective filtration area and high bondability of the fiber layer are contradictory.

The problems to be solved by the present invention include two points, that is, sufficient securing of an effective filtration area in the bag filter and high bondability of the fiber layer, and improvement of dust removal.

In order to achieve both sufficient securing of effective filtration area and high bondability of the fiber layer, when the bag filter fiber layer is laminated, the fibers constituting the bag filter are crushed by heat melting, adhesive application, etc. There is a problem that the total effective filtration area is reduced and the pressure loss of the bag filter is increased.

In the present invention, the adhesive surface between the laminated bag filter fiber layers is controlled to achieve a high bondability between the fiber layers and to reduce the pressure loss of the bag filter.

In addition, with regard to the improvement of the dust filterability in the bag filter, the dust collected by the bag filter can be obtained by laminating fibers having high slipperiness of air processed by the bag filter on the fiber layer constituting the bag filter. To prevent clogging of the bug filter and improve the ability to remove collected dust.

In order to achieve both the sufficient effective filtration area in the bag filter and the high bondability of the laminated fiber layers, and the improvement of dust removal in the bag filter, the nanofibers in the fiber layers that make up the bag filter When laminating the fibers and laminating the fiber layers, a step of subjecting the fiber layers constituting the bag filter to a hair burning treatment is provided to bond the fiber layers together.

    Regarding the structure of the bag filter in the present invention, the fiber layers constituting the bag filter have a five-layer structure, the first layer being the nonwoven fabric pre-layer 1, the second layer being the nanofiber fiber layer 2, and the third layer being The raw cotton layer 3 and the fourth layer are referred to as a base material layer 4, and the fifth layer is referred to as a raw cotton layer 5.

For the nonwoven fabric pre-layer 1, for example, polyethylene terephthalate, polypropylene, nylon, acrylic, glass, aramid, polyurethane, etc. having a fiber diameter of 1 to 50 μm and a fiber basis weight of 2 to 50 g / m 2 are used.

The manufacturing method of the nonwoven fabric pre-layer 1 is not particularly limited, and is formed by, for example, a dry method, a wet method, a spun bond method, a melt blow method, or the like.

For the nanofiber fiber layer 2, for example, polyethylene terephthalate, polypropylene, nylon, acrylic, polyethersulfone, polyurethane, aramid, or the like having a fiber diameter of 50 to 700 nm and a fiber basis weight of 0.1 to 10 g / m 2 is used.

The second nanofiber fiber layer 2 is formed by, for example, an electrospinning method, and nanofiber fibers are directly sprayed on the first nonwoven fabric pre-layer 1.

For the third raw cotton layer 3, for example, polyethylene terephthalate, polypropylene, nylon, acrylic, glass, aramid, etc., having a fiber diameter of 1 to 50 μm and a fiber basis weight of 50 to 400 g / m 2 are used.

For the base material layer 4 of the fourth layer, for example, polyethylene terephthalate, polypropylene, nylon, acrylic, glass, aramid or the like having a fiber diameter of 5 to 100 μm and a fiber basis weight of 30 to 300 g / m 2 is used.

For the fifth raw cotton layer 5, for example, polyethylene terephthalate, polypropylene, nylon, acrylic, glass, aramid or the like having a fiber diameter of 1 to 50 μm and a fiber basis weight of 50 to 400 g / m 2 is used.

In configuring the bag filter in the present invention, first, the raw cotton layer 3, the base material layer 4, and the raw cotton layer 5 are laminated in this order, and needling is performed so that the fiber layers are entangled with each other.

And the nonwoven fabric pre-layer 1 which sprayed the nanofiber fiber is used as the surface nonwoven fabric layer, and the fiber layer which gave the needling process to the raw cotton layer 3, the base material layer 4, and the raw cotton layer 5 is used as a filter cloth layer. Regarding the method for adhering the surface nonwoven fabric layer and the filter cloth layer, first, only the surface of the raw cotton layer 3 constituting the filter cloth layer is burned using a burner or the like, and a unit area of 10 on the surface of the raw cotton layer 3 is obtained. % To 25% are formed.

    A surface nonwoven fabric layer is laminated on the filter cloth layer that has been subjected to the hair-burning treatment, and the surface nonwoven fabric layer and the filter cloth layer are pressure-bonded and adhered using a calender roll. The laminated structure of the bag filter fibers is a filter cloth layer composed of a first nonwoven fabric pre-layer 1, a raw cotton layer 3, a base material layer 4, and a raw cotton layer 5, and a second nanofiber fiber layer 2. Are stacked so as to sandwich. The hair burning portion 11 of the filter cloth layer that has been subjected to the hair burning treatment is in contact with the nonwoven fabric pre-layer 1 in such a manner as to sandwich the nanofiber fiber layer 2 therebetween.

After the hair burning part 11 contacts the nonwoven fabric pre-layer 1 of the first layer, the contact part is pressure-bonded using a calender roll. Only the burned portion 11 of the filter cloth layer becomes an adhesive portion, and the nonwoven fabric pre-layer 1, the nanofiber fiber layer 2, and the filter cloth layer are melt bonded. In the fiber layer constituting the bag filter, the bonding process is performed only on the portion of the burned portion 11 on the filter cloth layer and the portion of the nonwoven fabric pre-layer 1 and the nanofiber fiber layer 2 that is in contact with the burned portion 11. The effective filtration area of the filter is not significantly reduced.

Next, the dust collecting mechanism and dust removing mechanism of the bag filter according to the present invention will be described.

In the bag filter of the present invention configured by laminating five fiber layers, first, the first nonwoven fabric pre-layer 1 collects dust having a large particle diameter as a pre-layer.

The second nanofiber fiber layer 2 collects fine particles that could not be collected by the first nonwoven fabric pre-layer 1 and also has surface smoothness that is a characteristic of nanofiber fibers having a small fiber diameter. By utilizing the above, air resistance to the fiber is suppressed, so that the pressure loss of the bag filter can be reduced. Further, the smoothness of the surface of the nanofiber fiber layer 2 makes it possible to smoothly remove dust by compressed air, thereby improving dust removal efficiency and preventing the bag filter from clogging.

    The filter cloth layer constituted by the third to fifth layers mainly has a function of maintaining the strength of the bag filter.

The compressed air ejected from the compressed air ejecting device 13 is continuously blown toward the downstream side of the bag filter, that is, toward the raw cotton layer 5 constituting the bag filter, with a predetermined interval, and into the bag filter. The dust that has entered and dust that has adhered to the upstream fiber surface is removed to the hopper 15.

The filter cloth layer constituting the bag filter is subjected to a hair-burning process, and the filter cloth layer, the nanofiber fiber layer 2 and the nonwoven fabric pre-layer 1 are pressure-bonded, thereby preventing the nanofiber fibers from being crushed more than necessary. A bug filter can be manufactured. In addition, by applying two bonding steps, that is, a needling process and a pressure bonding process through a hair burning process, to the fiber layer, it is possible to manufacture a laminated bag filter having high bondability.

By not crushing the nanofiber fibers constituting the nanofiber fiber layer 2 more than necessary, the surface smoothness that is the characteristic of the nanofiber fibers is maximized without reducing the effective filtration area of the nanofiber fiber layer in the bag filter. It can be used for bug filters.

By utilizing the surface smoothness characteristic of nanofiber fibers in the bag filter, it is possible to reduce the pressure loss of the bag filter and improve the dust removal performance. By laminating the nanofiber fiber layer 2 on the bag filter, air can smoothly pass through the nanofiber fiber layer 2, lowering the pressure loss of the bag filter, and removing dust attached to the nanofiber fiber layer 2. Improvement is expected.

In addition, the maintenance cost of the bag filter can be reduced by reducing the electricity cost by reducing the pressure loss of the bag filter and improving the dust removal performance.

Cross section of bag filter Bonding diagram of nonwoven fabric pre-layer 1, nanofiber fiber layer 2 and raw cotton layer 3 Filter cloth layer 3 after hair burning treatment Schematic diagram of dust collector

Hereinafter, the form of the laminated bag filter in the present invention will be described.

The bag filter in the present invention is composed of five fiber layers: a nonwoven fabric pre-layer 1, a nanofiber fiber layer 2, a raw cotton layer 3, a base material layer 4, and a raw cotton layer 5. In manufacturing the bag filter, first, a filter cloth layer composed of the raw cotton layer 3, the base material layer 4, and the raw cotton layer 5 is formed. Then, the surface nonwoven fabric layer which sprayed the nanofiber fiber on the nonwoven fabric pre-layer 1 is comprised, and is laminated | stacked on this filter cloth layer.

    With respect to the method for producing the filter cloth layer, a needling process is performed to entangle the fibers of each layer in the raw cotton layer 3, the base material layer 4, and the raw cotton layer 5 to form a three-layer filter cloth layer.

After the needling process, only the surface of the raw cotton layer 3 constituting the filter cloth layer is subjected to a hair burning treatment using a burner or the like. At this time, a 10% to 20% granular fried portion per unit area is formed on the surface of the raw cotton layer 3 on the surface of the raw cotton layer 3.

The range to which the hair-burning treatment is performed is limited to a range of about 10 to 25% per unit area of the surface of the raw cotton layer 3, and is preferably about 15%. When the range which performs a hair-burning process is too small, the adhesive strength of the laminated fiber layer will become weak. On the contrary, when the range which performs a hair-burning process is too large, an adhesion location will crush the effective filtration surface in the nanofiber fiber layer 2, and the surface smoothness which is the characteristic of a nanofiber fiber, and the collection efficiency with respect to a microparticle will reduce. Will be.

Regarding the surface nonwoven fabric layer constituted by the nonwoven fabric pre-layer 1 and the nanofiber fiber layer 2, nanofiber fibers are sprayed onto the nonwoven fabric prelayer 1 using an electrospinning generator.

After forming the surface nonwoven fabric layer, the surface nonwoven fabric layer and the filter cloth layer are sandwiched between the filter cloth layer constituted by the raw cotton layer 3, the base material layer 4, and the raw cotton layer 5 and the nonwoven fabric pre-layer 1 so as to sandwich the nanofiber fiber layer 2. Laminate. When laminating the surface nonwoven fabric layer and the filter cloth layer, the scalloped portion 11 on the raw cotton layer 3 constituting the filter cloth layer passes through the nanofiber fiber layer 2 by a calender roll, and the nonwoven fabric pre-layer. By contacting 1, the surface nonwoven fabric layer and the filter cloth layer adhere to each other, and a pressure-bonding process is performed.

The nonwoven fabric pre-layer 1, the nanofiber fiber layer 2, and the raw cotton layer 3 constituting the filter cloth layer are bonded to each other by the burned portion 11 formed on the surface of the raw cotton layer 3. The constituting raw cotton layer 3, the base material layer 4, and the raw cotton layer 5 are joined so that the fibers of each layer are intertwined by needling.

The bag filter fiber layer that has been subjected to the adhesion treatment and is composed of the nonwoven fabric pre-layer 1, the nanofiber fiber layer 2, the raw cotton layer 3, the base material layer 4, and the raw cotton layer 5 is finally a cylindrical bag-like bag Processed as a filter.

Because it is a highly durable multi-layer bag filter, it can be used in the field where more air is processed. In addition, since the pressure loss of the bag filter has been reduced by laminating the nanofiber fiber layers, it can be widely used in the field where energy consumption and maintenance costs are to be suppressed.

DESCRIPTION OF SYMBOLS 1 ... Nonwoven fabric pre-layer 2 ... Nanofiber fiber layer 3 ... Raw cotton layer 4 ... Base material layer 5 ... Raw cotton layer 6 ... Raw cotton layer 7 ... Hair-burning place 8.・ Nonwoven fabric pre-layer 9 ... raw cotton layer 10 ... nanofiber fiber layer 11 ... burnt portion 12 ... bag filter 13 ... compressed air jetting device 14 ... dust collector 15 ... Hopper section

Claims (1)

In a bag filter comprising a filter cloth layer and a surface nonwoven fabric layer, the filter cloth layer is formed by sequentially laminating a raw cotton layer 3, a base fabric layer 4 and a raw cotton layer 5 and integrating them by needling. Composed of a pre-layer 1 and a nanofiber fiber layer 2, the surface of the raw cotton layer constituting the filter cloth layer is composed of 10% or more and 25% or less of the sinter of the filter cloth layer. Adhering treatment is applied only to the part where the nonwoven fabric pre-layer and the nanofiber fiber layer are in contact with the sinter, and the nonwoven fabric pre-layer, nanofiber fiber layer and filter cloth layer are adhered. Feature bug filter.