JPH0538359A - Element for cleaning air - Google Patents

Abstract

PURPOSE:To obtain an adsorptive element which has a small pressure loss and maintains the superior adsorptive faculty even in the use with a high air quantity, by attaching an adsorbent on a braided article having a projection part in ridge form on the surface and forming the braided article to a cylindrical form through lamination or winding. CONSTITUTION:A base member on which an adsorbent is attached consists of a braided article 2 having a projection part 1 in ridge form on the surface. Accordingly, the braided article 2 having the projection part 1 bulging in linear form as the ridge on the surface of a plowed field is used. As the adsorbent, activated carbon is preferable, and the adsorptivity can be improved furthermore by adding phosphoric acid, malic acid, ascorbic acid, etc. In oder to attach the adsorbent on the braided article, a binder is used. The braided article attached with the adsorbent is used in a cylindrical form by lamination or winding. Such an adsorptive element possesses the less pressure loss and the superior deodorant effect, even in the case of a large air stream quantity.

Description

TECHNICAL FIELD The present invention relates to a deodorizing and dust-removing element used in an air cleaner for removing a malodor in the air. It is an air cleaning element that is suitable for low and large processing capacity.

 [Prior art] As an adsorption element of an air cleaner used to absorb and remove malodorous components in the air, an adsorption layer filled with granular activated carbon and fibrous activated carbon were made into paper and corrugated and laminated. Filters, corrugation-processed and laminated filters have been used in which fine powder of activated carbon is attached to a non-woven fabric such as a filter or glass fiber or synthetic fiber using a binder.

 However, recently, adsorption elements for air purifiers are used with a large amount of air flow, so that there is a demand for particularly low pressure loss and relatively high adsorption efficiency. Therefore, the conventional filter is not suitable in terms of pressure loss.

 In addition, electrostatic air cleaners or electrostatic precipitators have been used in the past to remove airborne dust. They charge dust particles by a corona discharge and collect and remove these particles by electrodes or filters with opposite charges. However, due to corona discharge, a high voltage of several KV or several tens of KV is required to charge the dust particles, which is not only dangerous in handling but also may cause a fire. Therefore, there is a strong demand for dust collectors that do not require high voltage, and various filters that do not rely on the electrostatic effect have been proposed. Since it is necessary to collect dust with a diameter of 1 μm or less, it is unavoidable that a filter with a very high pressure loss is required. Therefore, with this method, it was extremely difficult to remove dust particles efficiently with low pressure loss.

 [Problems to be Solved by the Invention] The granular activated carbon adsorption layer which has been used most frequently in the past is not suitable for use with a large air volume because it has a large ventilation resistance. Therefore, in order to reduce the pressure loss, a sheet-shaped adsorbent that is corrugated and rolled up is often used.

 However, after corrugation, the adhesive used to bond the corrugated sheet and the flat sheet permeated the activated carbon layer and covered the surface of the activated carbon, which hindered the adsorption ability. Therefore, there has been a demand for an adsorption element that has a small pressure loss and does not deteriorate the adsorption capacity of activated carbon even when used in a state where the air volume is large.

 In addition, in order to purify the air inside or inside the vehicle, it is necessary to remove fine dust such as cigarette smoke and odor.

 [Means for Solving Problems] The inventors of the present invention have confirmed that a part of a knitted fabric is thick as a base material of an adsorption element capable of retaining the adsorption ability of activated carbon and extremely reducing pressure loss. , And found that those having a large number of ridges on the surface are suitable.

 Furthermore, it has been known that an electret filter is suitable for removing fine dust such as cigarette smoke safely and at low cost, but it is extremely effective to combine both of them. And found the present invention.

 That is, an adsorbent is attached to a knitted fabric whose surface has a ridge-like convex portion, and the adsorbent is laminated or wound to form a columnar air-cleaning element and the above element. This is an air cleaning element that combines an electret filter.

 Hereinafter, the present invention will be described in detail.

 In the present invention, as the base material to which the adsorbent is attached, it is necessary to use a knitted fabric having a ridge-shaped convex portion on the surface. The ridge-shaped convex portion refers to a linearly raised shape such as a ridge on the surface of the field as shown in Fig. 1, but the ridge shape may be straight or curved. But it can also be irregular. The shape of the ridge cross section may be rectangular, semicylindrical, or irregular. For example, if a knitted fabric having a structure such as a double russell knit is used, such a shape can be easily obtained. The knitted fabric is not limited to a specific structure, but it is preferable that the knitted fabric has a large contact area with air and a large adsorbent loading.

 In addition, in order to prevent the raised parts such as ridges from falling when laminating or winding sheets with such a structure, a small amount of thread for connecting the ridges to each other at the top of the ridges is perpendicular to the ridges. It may be in the direction of.

 Any adsorbent can be used as long as it is effective for removing malodor in the air such as activated carbon, zeolite, and plant essential oil. In particular, activated carbon is a unique material having extremely excellent adsorptivity as a non-polar adsorbent, and is suitable because it exhibits high adsorptivity for almost all gaseous substances. However, activated carbon also has insufficient adsorption capacity for acetaldehyde, ammonia, lower amines, hydrocarbons, hydrogen sulfide, etc. contained in tobacco smoke. Therefore, in order to improve the adsorptivity of activated carbon, activated carbon impregnated with other substances such as phosphoric acid, malic acid, ascorbic acid may be used.

 The method of attaching these adsorbents to the knitted fabric is not particularly limited, but the method of using a binder is the simplest. However, when a binder is used, it is inevitable that the adsorption capacity will decrease to some extent, but it is preferable to use a latex type in which the adsorption capacity is relatively small. The particle size of the activated carbon and other gas absorbers used is 100 mesh pass or less, preferably 300 mesh pass or less, from the viewpoint of dispersion stability when mixed with latex, and the adsorbent suspension with good adherability is used. A suspension can be prepared.

 In the present invention, it is necessary to laminate or wind a knitted fabric having a ridge-shaped convex portion with an adsorbent attached thereto for use as a column. For example, the shape is as shown in FIG. 2 or FIG. These shapes can be modified and used as needed. For example, in the case of FIG. 2, the side surface has a trapezoidal shape or a shape having a gouged portion, and in FIG. 3, the shape is an elliptical shape, which is pressed into a mold to form a rectangular parallelepiped.

 In addition, when laminated, the adhesive area between layers is much smaller due to its structure, as compared with the case of corrugated laminated layers, and therefore the decrease in adsorption capacity is small.

 With the above-mentioned shape, even when a large amount of air is blown, the pressure loss is very low, the air passes through the inside of the knitted fabric, and the air comes into contact with the adsorbent, so that the deodorizing effect is excellent.

 The air purifying element of the present invention incorporates an electret filter. The material of this filter is electrically polarized, in other words, it always has a constant electrostatic charge.

Therefore, since ultrafine particles with a diameter of 1 μm or less, such as cigarette smoke, usually have a positive charge, they are attracted to the negatively charged portion of the electret filter. Therefore, it can be efficiently removed with a low pressure loss.

Such ultrafine particles are considerably difficult to remove by ordinary filtration and require high pressure loss. The electret filter is usually made of a material which is polarized by electret treatment to become a dielectric, for example, a polymer such as polyethylene, polypropylene, polyester or polyvinyl fluoride. Various methods are known as permanent polarization methods. Usually, a dielectric is sandwiched between electrode plates to raise the temperature to near the softening point and then gradually cool to room temperature with a high DC voltage applied. Made by. Moreover, since this polarization state lasts for several years, it has the function of removing ultrafine particles for a long period of time. Moreover, since it is not necessary to apply high voltage when using it, it is easy to handle, there is no danger of fire, and safety is high.

 [Operation / Effect] As described above, the air purification element of the present invention has a large number of tubular passages along the flow passage in the air, so that even if a large amount of air is flowed, the pressure loss is extremely high. Since it is low, and the air passes through the inside of the knitted fabric, and the area where air contacts the adsorbent is large, the deodorizing effect is excellent when the air in the room or vehicle is circulated at high speed. In addition to ordinary activated carbon, if activated carbon impregnated with phosphoric acid, malic acid, ascorbic acid, etc. is used in order to improve the adsorption capacity for acetaldehyde, ammonia, lower amine, etc. contained in cigarette smoke, It is extremely suitable for removing the bad odor of cigarettes.

 Further, in the present invention, since the electret filter is combined, it is possible to efficiently remove the suspended dust in the air having a diameter of 1 μm or less with a low pressure loss. Therefore, it is highly effective in removing cigarette smoke and does not require high voltage as in the conventional method, so it is easy to handle and highly safe.

 [Examples] Hereinafter, the present invention will be specifically described with reference to Examples, but the present invention is not limited thereto.

 Example 1 As a knitted fabric having a ridge-shaped convex portion on the surface, a 3 denier 12-twisted polyester multifilament was used in the plane portion of the bottom surface, and a ridge-shaped thread was a 150 denyl nylon monofilament. is there. In addition, a flat part with a width of 1 mm was made on the top of each ridge with the same thread as the flat part. This flat portion acts so that the tips of the raised filaments of the multifilament do not come apart from each other and retain the shape of the ridge. The thickness of the flat part is 0.3 mm, the pitch of the ridges is 7 mm, and the thickness of the entire knitted fabric is 3 mm.

 100 parts of coconut shell activated carbon fine powder was dispersed in 120 parts of water, and 40 parts of a 2% CMC aqueous solution and 260 parts of 45% acrylonitrile butadiene latex were added as an adhesive to prepare a suspension. Next, the knitted fabric was dipped in the suspension, pulled up, squeezed, and dried at 120 ° C.

 A vinyl acetate emulsion adhesive was applied to the top of the ridges and laminated, and sliced perpendicularly to the surface of the knitted fabric to form a 5 mm thick element. The open area of one cell was 0.14 mm.

 Table 1 shows the relationship between the amount of activated carbon and the pressure loss of the element.

 The amount of activated carbon was measured according to JIS M-8812 “Industrial analysis method for coals and cokes”, and the pressure loss was measured at a wind speed of 1 m / sec at 25 ° C. and a sample thickness of 5 mm.

 The adsorption performance of the element is shown in FIG. The adsorption performance is shown by the relationship between the operating time of the air purifier and the hydrogen sulfide gas retention rate. The measuring method is as follows.

The element cut into 10 mm × 30 cm was mounted on an air purifier capable of processing gas at a wind speed of 1 m / sec, and set in a 1 m ³ acrylic box in which the hydrogen sulfide gas concentration was adjusted to 100 ppm in advance.

 The relationship between the air circulation time and the residual hydrogen sulfide gas concentration was investigated. The result is shown in FIG.

 High-sensitivity gas chromatography with FPD detector (Flame Ionization Detector) was used for gas concentration measurement.

Comparative Example 1 A cell-free product of a polyurethane foam sheet (8 cells in 1 inch, thickness 5 mm) was immersed in the same activated carbon suspension as in Example 1, and the activated carbon adhesion amount was changed to that in Example 1. The same amount was applied and dried at 120 ° C. Furthermore, the same element as in Example 1 was prepared. The opening area of one cell was 0.14 cm ² .

 Similar to Example 1, the relationship between the amount of activated carbon and the pressure loss of the element, and the relationship between the operating time of the air cleaning device and the residual rate of hydrogen sulfide gas were measured. The results are shown in Table 1 and FIG.

Comparative Example 2 Activated carbon-containing paper having a content rate of activated carbon fibers of 50% and a thickness of 0.25 mm was made into paper, corrugated and laminated to form a molded body, which was sliced into a thickness of 5 mm. The opening area of one cell was 0.15 cm ² .

The relationship between the amount of activated carbon and the pressure loss of the element, and the relationship between the operating time of the air cleaning device and the residual rate of hydrogen sulfide gas were measured in the same manner as in Example 1. The results are shown in Table 1 and FIG.

 Example 2 An element shown in FIG. 4 was prepared by combining the deodorizing filter shown in FIG. 3 and a sheet-shaped electret filter.

 In Example 1, in the apparatus used for the adsorption test of hydrogen sulfide gas, cigarette smoke was enclosed instead of hydrogen sulfide gas, and the element having the same size as that of Example 1 and having the configuration shown in FIG. did. As a result, the smoke odor and purple color completely disappeared in about 10 minutes.

[Brief description of drawings]

 FIG. 1 shows an enlarged perspective view of a knitted fabric having a ridge-shaped convex portion. FIG. 2 is a perspective view of a deodorizing element in which activated carbon is impregnated on a knitted fabric having a ridge-shaped convex portion and the activated carbon is laminated. FIG. 3 shows a perspective view of a deodorizing element formed by impregnating activated carbon on a knitted fabric having a ridge-shaped convex portion and winding the activated carbon into the fabric. FIG. 4 shows a perspective view of an air cleaning element in which the deodorizing element shown in FIG. 2 and an electret filter are combined. DESCRIPTION OF SYMBOLS 1 ... On the surface of a knitted part, which is a ridge-like convex part 2 ... Knitted fabric 3 ... External cover 4 ... Electret filter 5 ... Example 1 6 ... Comparative example 1 7 ... Comparative example 2

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[Procedure amendment]

[Submission date] September 14, 1989 (1) The following 2 is inserted between the description, page 16, line 5 "4 ... Electret filter" and line 6 "5 ... Example 1".
Insert a row. "Fig. 5 shows the relationship between the operating time of the air cleaning device and the residual rate of hydrogen sulfide gas."

Claims (3)

[Claims] 1. An air-cleaning element in which an adsorbent is affixed to a knitted fabric having a ridge-shaped convex portion on the surface thereof, and the adsorbent is laminated or wound into a columnar shape. 2. A gas-absorbing filter portion in which a knitted fabric having a ridge-shaped convex portion on the surface thereof is attached with an adsorbent, and the adsorbent is laminated or wound to form a columnar shape, and an electret filter. An air cleaning element that combines a number of elements. 3. The air-cleaning element according to claims 1 and 2, wherein activated carbon is used as an adsorbent.