JPH07241491A - Air cleaning filter - Google Patents

Abstract

PURPOSE:To provide a honeycomb air cleaning filter consisting of a flute and a liner, capable of sufficiently holding its shape without using any auxiliary member such as a reinforcement, maintaining a balance of the treated air flow and capable of effectively removing dust and malodor at the same time with a good balance. CONSTITUTION:The flute 1 is formed with dust removing electret sheet-shaped nonwoven fabric and the inner 2 with a sheet-shaped activated carbon coated with a deodorant, or the flute 1 is formed with the sheet-shaped activated carbon and the liner 2 with dust removing. electret sheet-shaped nonwoven fabric. A miniaturized air cleaning filter 3 having a low pressure drop is obtained in this way.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air purifying filter capable of effectively removing both dust and odorous components, and more specifically, as a filter in an air purifying device, a filter in an air conditioner or the like. The present invention relates to an air purifying filter that can be used as.

[0002]

2. Description of the Related Art The increase in the tightness of living spaces, the generalization of the use of carpets, the spread of smoking ideology and the increase of allergic diseases, and the boom in raising pets at home. As a background, it has been demanded to remove dust and odor generated in the room of a general household. Also offices, cars, factories,
The above-mentioned demand is further increasing in facilities and facilities where the removal of dust and odors has conventionally been a problem, such as inside warehouses and hospitals. Therefore, various improvements are being studied not only for filters installed in dedicated air purifiers, but also for filters installed in air conditioners such as room air conditioners and fan heaters.

The conventional filter used for the above purpose is a type in which a filter for deodorization or a filter for dust removal is independently configured and used in an appropriate combination. First of all, the deodorizing filter will be described. A coarse net or a continuous foam type urethane resin sheet with activated carbon particles or a deodorant adhered thereto, or a fibrous activated carbon sheet with a deodorant impregnated and the sheet continuously corrugated. A so-called honeycomb shape is formed by further stacking the molded products and adhering the two contact points (single cardboard type: the former sheet is the liner part and the latter corrugated product is the flute part). Things are generally used.

On the other hand, as a filter for removing dust, it is becoming common to use a sheet-shaped non-woven fabric in the form of an electret, and this is not simply used in a sheet-like state, but it is possible to reduce pressure loss and dust removal performance. For the purpose of improvement, it has been studied to fold it into a pleat shape, or to use an electretized sheet in the same honeycomb shape as described above. However, as a material for the electretized sheet, for example, a polypropylene film or the like is generally used, so that it is not very elastic, and it is difficult to obtain practical strength in any of the pleated shape and the honeycomb shape, and some kind of reinforcing member is used. There was a problem that had to be. Therefore, not only the bulkiness factor due to the combined use of the deodorization exclusive filter and the dust removal exclusive filter, but also the bulkiness factor due to the combined use of the reinforcing member is added, so that there is a problem that the size as a whole must be increased. Therefore, not only the pressure loss increases due to the combined use of each dedicated filter, but also the size of the air purifying device (including the dedicated purifying device and the cooling and heating device, the same applies hereinafter) is increased due to the increase in the filter space. This causes a noise problem due to an increase in the load of the blower, and with respect to the latter size increase, there arises a problem that it cannot meet the demands for downsizing and thinning of the device.

Among these problems, Japanese Patent Application Laid-Open No. 4-4011 has been proposed as a technique for suppressing an increase in pressure loss. This proposed method uses a wide range of dedicated dust-removing honeycomb-shaped filter bodies in which a plurality of tubular passages surrounded by flutes and liners are formed by alternately stacking a plurality of stages of liners and flutes of an electretized sheet, and a wide range for deodorization. It uses a structured activated carbon porous body exclusively for deodorization,
In stacking these, the tubular passages of the honeycomb filter body are arranged parallel to the air flow direction. That is, a configuration in which air flows along the tubular passage (hereinafter referred to as parallel flow) is adopted. Therefore, in this method, it is possible to reduce the pressure loss of the honeycomb structure part that shares dust removal, but in order to sufficiently enhance this dust removal effect, it is necessary to lengthen the air passage to some extent, and in the same manner as that. The pressure loss of the activated carbon porous body portion formed extremely thick (thick in the air flow direction) becomes extremely high. Therefore, the overwhelming portion of the air flow flows toward the honeycomb body on the low pressure loss side, and hardly flows toward the activated carbon porous body on the high pressure loss side. When such an imbalance of flow occurs, the latter action (deodorizing action) becomes practically unexpectable.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and by devising the material constitution of the entire filter, an auxiliary member such as a reinforcing material can be used. In addition to exerting sufficient shape retention by itself, it is possible to maintain the balance of the flow of the processing air and achieve both purposes of dust removal and odor removal in a well-balanced manner, and by doing so, low pressure loss and It is intended to provide a downsized air purifying filter structure.

[0007]

An air purifying filter structure according to the present invention, which has been able to achieve the above object, is a honeycomb body composed entirely of flutes and liners. Is a honeycomb air purification filter composed of a flute part and a liner part, wherein the flute part is made of electretized sheet-like nonwoven fabric for removing dust, and the liner part is a sheet-like activated carbon with a deodorant attached. According to the invention of claim 2, the flute part is made of a sheet-like activated carbon impregnated with a deodorant, and the liner part is made of an electretized sheet-like non-woven fabric for removing dust. It is what

That is, when viewed from the inside of the tubular passage surrounded by the flute portion and the liner portion, one wall surface is an electret sheet-like nonwoven fabric for removing dust (hereinafter referred to as EF sheet).
And the other wall surface is made of sheet-like activated carbon (hereinafter referred to as AC sheet) to which a deodorant is attached.
Therefore, the air to be treated flowing through the tubular passage uniformly contacts both of the wall surfaces in the process of spirally flowing, and the dust removal and deodorization are performed by the respective actions. Since the flute portion is corrugated, the surface area of the flute portion in the tubular passage is larger than the surface area of the liner portion. Therefore, when the object to be removed in the air to be treated is mainly dust, it is recommended that the flute part be an EF sheet and the liner part be an AC sheet. If the object to be removed is mainly an odor component, the flute part should be AC. It is recommended to use a sheet and the liner part is an EF sheet.

[0009]

FUNCTION The EF sheet is made of a non-woven fabric, which is a material of which permanent polarization is applied, and always has a certain electric charge. Therefore, dust in the air passing through the surface is adsorbed by the electrostatic force on the EF sheet and removed from the air. The EF sheet is made of a non-woven fabric using an electretized derivative as a material, and examples of the material for such a derivative include thermoplastic materials such as polyvinylidene fluoride, polyethylene, polypropylene, polyamides and polyesters. Resin is used. Further, as a manufacturing method thereof, a thermal electret method, an electro electret method, a photo electret method or the like is used. The thermal electret method among them will be described. A nonwoven fabric made of the above material is sandwiched between two electrode plates and held at a temperature slightly lower than the softening temperature of the above material. Then, while applying high DC voltage to this, cool it to room temperature. This method is generalized as a particularly effective method because it has good operability and has a characteristic that the life of injected charges extends for several years.

In any case, since the EF sheet electretized by these methods is used as either the liner portion or the flute portion in the honeycomb as described above, it has a sheet shape which can be formed into such a shape. Provided. Since the EF sheet of the present invention is one in which air flows in parallel lines with respect to the sheet surface, the treated air does not penetrate the sheet, and thus the sheet thickness is not particularly limited, but from the viewpoint of increasing the dust adsorption capacity, air is used. It is desirable that the fine dust inside can be taken up to the inside of the sheet, and for that reason, air easily enters the nonwoven fabric,
It is sometimes recommended to be thin enough and have a suitable bulk density so that it can pass through it. The preferred thickness is 2.1 mm or less, more preferably 1.5 mm or less, while the bulk density is preferably 0.03 g / cm ³ or more,
It is more preferably 0.25 g / cm ³ or less, and even more preferably 0.20 g / cm ³ or less.

On the other hand, the AC sheet for deodorization is composed of activated carbon-containing paper containing activated carbon fibers and / or granular activated carbon. The activated carbon-containing paper may be composed of activated carbon fibers alone, but may also be composed of other natural or synthetic pulp materials, or PVA fiber papermaking binders, etc., in order to enhance shape retention. Good. At this time, it is desired that the active carbon content be at least 10% by weight or more. Further, it is desired that the activated carbon-containing paper is thin and has sufficient porosity so that the substance to be adsorbed in the air can quickly permeate and diffuse into the inside of the sheet. The preferred bulk density therefor is 0.1 to 0.4 g / cm ³ , more preferably 0.1.
15 g / cm ³ or more, or more preferably 0.30 g / cm ³
It is not more than cm ³ . Preferred thickness is 0.05 to 0.80
mm, more preferably 0.1 mm, and preferably 0.6 mm or less.

If necessary, the activated carbon-containing paper may contain an acid adsorbing substance or an alkali adsorbing substance. The acid adsorbing substance is not particularly limited as long as it is capable of adsorbing an acidic substance, has low volatility per se, and is highly stable to some extent, for example, monoethanolamine, diethanolamine, polyalkylenepolyamine and the like. The organic amines or guanidines such as guanidine phosphate and guanidine sulfamate can be used. The alkali adsorbing substance is not particularly limited as long as it is capable of adsorbing an alkaline substance, has low volatility itself, and is highly stable to some extent, for example, organic acids such as malic acid, citric acid and tartaric acid. Examples thereof include mono- or polycarboxylic acids. These adsorbents may be added when making paper containing activated carbon,
It may be attached and dried after paper making. The amount of impregnation is preferably 1 to 50% by weight based on the weight of the filter material.

As described above, the present invention combines the EF sheet and the AC sheet as the liner portion or the flute portion, and when the odor component is only the alkaline substance or only the acidic substance, the AC substance is used. A filter of the present invention is prepared by preparing either a sheet containing an acid adsorbing substance or a sheet containing an alkali adsorbing substance and combining this with an EF sheet. However, when the odorous components include both alkaline and acidic odor components, the AC sheet containing the acid adsorbing substance and the AC sheet containing the alkaline adsorbing substance are separately prepared. Then, the filter of the present invention may be prepared by separately making a liner portion and a flute portion using all three types of materials including the EF sheet. In this case, the most preferable combination is that the EF sheet is either the liner portion or the flute portion, and for the remaining flute portion or liner portion, both the acid adsorbing substance-containing AC sheet and the alkali adsorbing substance-containing AC sheet are odor components. It is recommended to use in combination at an appropriate ratio in consideration of the composition and content of. By appropriately selecting such a combination, two types of sheets in which the tubular passage surrounded by the flute portion and the liner portion is selected from an EF sheet, an acid adsorbing substance-containing AC sheet, and an alkali adsorbing substance-containing AC sheet Is configured as a wall surface. Therefore, it is desirable to adopt a combination that achieves the optimum cleaning effect according to the contamination content of the air to be treated. In addition, a filter of the present invention consisting of only an EF sheet and a sheet containing an acid adsorbing substance is made, and another filter of the present invention consisting only of an EF sheet and a sheet containing an alkali adsorbing substance is separately prepared, and these are used in an appropriate combination for convenience. Also included in the filter of the present invention.

The means for molding the honeycomb filter of the present invention is arbitrary, but a typical procedure will be described as an example. First, a normal corrugated board processing machine can be used for molding. Therefore, one side of the corrugated sheet (flute portion) processed into a corrugated shape and the contact point of the flat sheet (liner portion) are joined to form a single corrugated cardboard. The corrugated cardboard is stacked or rolled into a roll to form a honeycomb filter.

When corrugated cardboards are stacked and formed into a honeycomb shape, it is general to apply and fix an adhesive on the wave vertices of the corrugated sheet, but when the case is filled with a plastic resin or the like, it is bonded. It does not have to be fixed by the agent. FIG. 1 shows a cross-sectional view of a single corrugated cardboard, FIG. 2 shows a cross-sectional view of a honeycomb filter in which single-corrugated cardboards are stacked, and FIG. 3 shows a cross-sectional view of a honeycomb formed by rolling it into a roll shape.

The thickness and width of the tubular passage are determined by the pitch and height of the corrugated sheet, and the pressure loss when air flows through the narrow passage increases. Is large, the length of the laminate required for removal can be shortened. Therefore, it is necessary to consider these factors comprehensively, and also to consider the degree of contamination of the air to be treated, and to design an appropriate thickness. A preferred wave pitch is 30 to 150 per 30 cm, and a preferred wave height is 0.6 to 8.0 mm, more preferably 0.8 to 6.0 mm.

The present invention will be specifically described with reference to the following examples, but the following examples do not limit the present invention.
All modifications within the scope of the above and the following are included in the technical scope of the present invention.

[0018]

EXAMPLES Various air purification filters were prepared and their characteristics were measured. Example 1 Electretized polypropylene sheet-like nonwoven fabric (14 μm, basis weight 50 g / m ² , thickness 0.35 m)
m, bulk density 0.14 g / cm ³ ) as a flute part, and powdered activated carbon-containing paper (60% activated carbon content, weight per unit area 10)
0 g / m ² , thickness 0.3 mm, bulk density 0.3 g / cm
³ ) Papermaking and then 10% malic acid (ammonia adsorbent) adhering and drying was used as the liner part, and the wave pitch was about 3.
A piece of corrugated cardboard having a size of 1 mm and a wave height of about 2 mm was formed. The obtained single corrugated cardboard was stacked in 21 stages to prepare a honeycomb air purifying filter having a height of 65 mm, a width of 300 mm, and a layer length (t in FIG. 2) of 10 mm. The ratio of the length of the flute portion to that of the liner portion of this one-piece cardboard was 1.5: 1.

Example 2 Same as Example 1 except that the same material as used in Example 1 was used, the electretized sheet-shaped nonwoven fabric was used as the liner portion, and the powdered activated carbon-containing paper was used as the flute portion. To create an air purification film.

Comparative Example 1 Electretized polypropylene sheet-like non-woven fabric (14 μm, basis weight 25 g / m ² , thickness 0.2 m)
m, bulk density 0.13 g / cm ³ ) was used for both the flute portion and the liner portion to form a corrugated cardboard having a wave pitch of about 3.1 mm and a wave height of about 2 mm. The height of the obtained electret non-woven fabric corrugated cardboard 21 is 6 layers.
A honeycomb air purifying filter having a size of 5 mm, a width of 300 mm, and a layer length of 5 mm was prepared.

Comparative Example 2 Powdered activated carbon-containing paper (same specifications as in Example 1) was used after papermaking, and 10% malic acid was impregnated and dried on both the liner portion and the flute portion, and a wave pitch of about 3. A piece of corrugated cardboard having a size of 1 mm and a wave height of about 2 mm was formed. The obtained single-sided corrugated cardboards are stacked in 21 stages to a height of 65 mm and a width of 300 m
A honeycomb air purifying filter having m and a layer length of 5 mm was prepared.

Comparative Example 3 Electretized polypropylene sheet non-woven fabric (14 μm, basis weight 50 g / m ² , thickness 0.35 m)
m, a bulk density of 0.14 g / cm ³ ) and a pleat shape-holding net (mesh size 6 mm × 6 mm, open area ratio 93%, basis weight 60 g / m ² ) after bonding to a pleat pitch of 3. After processing to 0 mm, height 65 mm, width 30
A pleated filter for 0 mm and a layer length of 5 mm dedicated to dust removal was prepared. In addition, a honeycomb filter (layer length 5 mm) having the same specifications as in Comparative Example 2 was prepared as an odor removing filter,
It was laminated on the pleated filter. Therefore, the layer length of the air purifying filter was 10 mm. The pleated filter was placed orthogonal to the air flow.

Comparative Example 4 The electret nonwoven fabric honeycomb of Comparative Example 1 and the honeycomb made of the odor-removing powdered activated carbon-containing paper of Comparative Example 2 were laminated. The layer length of the air purification filter was 10 mm. The characteristics of the air purification filter obtained as described above were measured.

Dust removal performance An air purifying filter was installed in the air purifier, and 2.7 m ³
Place it in the center of the acrylic resin case at a temperature of 25 ° C,
Tobacco (Mild Seven: trade name) is naturally burned in an environment of 50% relative humidity to make 5000 polluted environments with a dust measuring instrument, and the air purifier is operated for 70 minutes with a superficial linear velocity of 100 cm / sec. Was measured (see FIG. 4). The results are shown in Table 1. Removal performance (%) = (5000 particles-number of particles after 70 minutes (particles) / 50
00 pieces) x 100

Odor removing performance An air purifying filter is installed in a cylindrical glass tube having a diameter of 65 mm, and air (temperature 25 ° C., relative humidity 50%) containing 5 ppm of ammonia gas is supplied to the glass tube at a superficial linear velocity of 25 cm. / Sec, and the gas concentrations on the inlet side and the outlet side of the air purifying filter at that time were measured with a gas detector tube (see FIG. 5). The results are shown in Table 1. Removal performance (%) = (inlet gas concentration-outlet gas concentration / inlet gas concentration) x 100

A pressure loss air purification filter is installed in a cylindrical glass tube having a diameter of 65 mm, and the glass tube has a humidity of 25% and a relative humidity of 50%.
The air was blown at a linear velocity of 100 cm / sec. The pressure loss on the inlet side and the outlet side of the air purifying filter was measured, and the pressure difference was determined as the pressure loss. The results are shown in Table 1.

[0027]

[Table 1]

As shown in Table 1, the air cleaning filters of Examples 1 and 2 exhibited excellent performances in removing cigarette smoke particles and in adsorbing ammonia. Moreover, the layer lengths are comparative examples 3 and 4.
Despite being the same as the above, the pressure loss was low and the strength was higher. Comparative Example 1 is a filter for removing dust, which has excellent cigarette smoke removal performance, but does not have ammonia adsorption performance, and uses polypropylene, which has a weak stiffness, as a material, so pressure loss is high and filter strength is insufficient. there were. On the contrary, the odor adsorption filter of Comparative Example 2 has excellent ammonia adsorption performance, but does not have cigarette smoke removal performance. Comparative Example 3 is excellent in cigarette smoke removal performance, ammonia adsorption performance, and strength, but is not preferable because of high pressure loss. The combination of the dust removing honeycomb and the odor adsorbing honeycomb of Comparative Example 4 is not preferable because the pressure loss becomes large.

[0029]

EFFECT OF THE INVENTION The present invention is constructed as described above, and has an air purifying filter which has a small volume, efficiently achieves both dust removal and deodorization, is excellent in strength, and has a very small pressure loss. Could be provided.

[Brief description of drawings]

FIG. 1 is a sectional view of a single cardboard.

FIG. 2 is a perspective view of a honeycomb air purifying filter in which single-sided cardboards are stacked.

FIG. 3 is a perspective view of a honeycomb-shaped air purifying filter in which a piece of cardboard is wound.

FIG. 4 is a diagram showing a device for measuring the dust removal performance of a filter in the example.

FIG. 5 is a diagram showing a device for measuring the adsorption performance of a filter in the example.

[Explanation of symbols]

1 flute part 2 liner part 3 air purifying filter 4 2.7m ³ acrylic resin case 5 air purifier 6 malodorous gas mixed air 7 inlet concentration measuring port 8 outlet concentration measuring port 9 glass tube A air flow direction t layer length

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location B01D 46/00 ZAB 7446-4D 302 7446-4D 53/34 ZAB 53/38 53/81

Claims (2)

[Claims] 1. A honeycomb air purifying filter comprising a flute portion and a liner portion, wherein the flute portion is made of an electretized sheet-like non-woven fabric for removing dust, and is used as a liner portion. Is an air purification filter characterized by using a sheet-like activated carbon impregnated with a deodorant. 2. A honeycomb-shaped air purifying filter comprising a flute portion and a liner portion, wherein the flute portion is made of a sheet-like activated carbon impregnated with a deodorant, and the liner portion is An air purifying filter comprising a sheet-shaped non-woven fabric made of electret for removing dust.