Abstract:
There is provided a filter including elements, each being made from non-woven fabric, which are placed on one right after the other, the two outermost elements being coated with a waterproof agent. The filter according to the present invention provides an advantage of permitting air to smoothly pass through it and effectively removing moisture and fine dust particles from air passing through it, as well as preventing production of static electricity. Furthermore, the filter can be manufactured with ease.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates to a filter, a filter assembly with the filter, and cooling apparatus with the filter assembly. 
         [0003]    2. Description of the Conventional Art 
         [0004]    An electronic device for telecommunication is installed inside a housing with cooling apparatus. The cooling apparatus removed the amount of heat. If the cooling apparatus is faulty, the electronic device overheats and causes internal damage. The cooling apparatus includes a heat exchanger and cooling apparatus. 
         [0005]    The cooling apparatus, disclosed in Korean patent registration No. KR 10-0606523 includes fans, installed inside the housing with an air inlet and air outlet, and a motor. The motor rotates the fan. The fan pulls outside air into the housing. 
         [0006]    The electronic device is installed inside the housing. The electronic device is maintained at less than 65° C. for its proper operation. The electronic device is sensitive to moisture and fine dust particles. Moisture and fine dust particles have to be removed before outside air is introduced into the housing. 
         [0007]    To do this, a filter is installed in front of each of the air inlet and air outlet in the housing. The filter includes a frame, a porous element, and a sealing agent (or a shaped body) attaching the porous element to the frame. 
         [0008]    The porous element has pores, an average size of which is in the range of 0.5 to 20 μm (included). The porous element is waterproof. 
         [0009]    Moisture and fine dust particles are removed from outside air passing through the porous element. Outside air, from which moisture and fine dust particles are removed, picks up heat produced by the electronic device and then passes through the air outlet to carry it away. As a result, the electronic device is made cooler. 
         [0010]    The porous element may be made from ePTFE (expended-Poly Tetra Fluor Ethylene), woven fabric, or hosiery. However, porous ePTFE is difficult to make from fluorocarbon resin, such as Teflon. 
         [0011]    Furthermore, ePTFE is subject to production of static electricity. Static electricity, occurring when the porous element is touched, causes the porous element to be damaged. So, the porous element should be wrapped with a sheet of paper, instead of a packing material made of polyvinyl resin producing static electricity. 
         [0012]    The porous element, made from woven fabric, or hosiery, has pores of the same size. However, the size of the pores is too small and the pores are closely spaced in a uniform manner. This prevents smooth introduction of outside air into the housing. 
       SUMMARY OF THE INVENTION 
       [0013]    One object of the present invention is to provide a filter capable of permitting air to smoothly pass through it and effectively removing moisture and fine dust particles from air passing through it, a filter assembly equipped with the filter, and cooling apparatus equipped with the filter assembly. 
         [0014]    Another object of the present invention is to provide a filter capable of being manufactured with ease and of preventing production of static electricity, a filter assembly equipped with the filter, and cooling apparatus equipped with the filter assembly. 
         [0015]    According to one aspect of the present invention, there is provided a filter including elements, each being made from non-woven fabric, which are placed on one right after the other, the two outermost elements being coated with a waterproof agent. 
         [0016]    According to another aspect of the present invention, there is provided a filter assembly including a filter frame, and a filter provided on the filter frame, the filter including elements, each being made from non-woven fabric, which are placed on one right after the other, the two outermost elements being coated with a waterproof agent. 
         [0017]    According to another aspect of the present invention, there is provided cooling apparatus including a housing having an air inlet and an air outlet, inside which to install an electronic device, a fan provided inside the housing, pulling outside air into the housing, a fan motor driving the fan, and two filter assemblies being inserted into the air inlet and air outlet, respectively, each of the two filter assemblies including a filter frame, and a filter provided on the filter frame, the filter including elements, each being made from non-woven fabric, which are placed on one right after the other, the two outermost elements being coated with a waterproof agent. 
         [0018]    The foregoing and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWING 
         [0019]    The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention. 
           [0020]    In the drawings: 
           [0021]      FIG. 1  is a cross-sectional view of cooling apparatus, equipped with one embodiment of a filter assembly according to the present invention; 
           [0022]      FIG. 2  is a perspective view of the filter assembly as shown in  FIG. 1 ; 
           [0023]      FIG. 3  is a cross-sectional view of the filter assembly cut along a line III-III, as shown in  FIG. 2 ; 
           [0024]      FIG. 4  is a perspective view of a filter as shown in  FIG. 2 ; 
           [0025]      FIG. 5  is a front view of a portion of the filter assembly as shown in  FIG. 2 ; 
           [0026]      FIG. 6  is a perspective view of a mold for casting the filter assembly as shown in  FIG. 2 ; 
           [0027]      FIG. 7  is an expanded, perspective view of a portion of the filter assembly as shown in  FIG. 3 ; 
           [0028]      FIG. 8  is a picture of a dissembled portion of the one embodiment of the filter according to the present invention; and 
           [0029]      FIG. 9  is a picture of an expanded surface of a second or third element making up the filter as shown in  FIG. 8 . 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0030]    Referring to the accompanying drawings, a filter, a filter assembly equipped with the filter, and cooling apparatus equipped with the filter assembly according to the present invention. 
         [0031]      FIG. 1  is a cross-sectional view of cooling apparatus, equipped with one embodiment of a filter assembly according to the present invention. A dotted-line arrow indicates a direction in which air flows. 
         [0032]    As shown in  FIG. 1 , an electronic device E is installed inside a housing  10  with an air inlet  11  and air outlet  12  on the opposite sides. The housing  10  is placed outdoors on a concrete slab. The housing  10  protects the electronic device E from exposure to the weather and damage from the surrounding atmosphere. 
         [0033]    The cooling apparatus is installed inside the housing  10 . The cooling apparatus permits outside air to flow into the housing  10  through the air inlet  11 , pick up heat, and carry away through the air outlet  12 . 
         [0034]    The cooling apparatus includes a fan  20 , a motor  30 , and a filter assembly FA. 
         [0035]    The fan  20  and motor  30  are installed adjacent to the air outlet  12  inside the housing  10 . The two filter assemblies FA may be installed inside the housing  10 : one in line with the air inlet  11  and the other in line with the air outlet  12 . 
         [0036]      FIG. 2  is a perspective view of the filter assembly as shown in  FIG. 1 . 
         [0037]    As shown  FIGS. 1 and 2 , the filter assembly FA includes a filter frame  40  and a filter  50 . 
         [0038]    The filter frame  40  may be made of resin including urethane resin. The filter frame  40  may be made of aluminum, stainless steel, or plastic. The filter frame  40  has a rectangular hole in the middle. The rectangular hole in the filter frame  40  varies depending on a shape of the air inlet or air outlet  11  or  12 . 
         [0039]    The filter  50 , shaped like a rectangle, is inserted into the rectangular hole in the filter frame  40 . 
         [0040]      FIG. 3  is a cross-sectional view of the filter assembly cut along a line III-III, as shown in  FIG. 2 .  FIG. 4  is a perspective view of a filter as shown in  FIG. 2 . 
         [0041]    As shown in  FIG. 3 , the filter  50  is corrugated to maximize its filtering area. That is, the filter  50  is shaped into alternating ridges  1  and grooves  2 . 
         [0042]    As shown in  FIG. 4 , three support lines of olefin resin are formed on the upper, middle, and lower portion of the filter  50 . The three support lines  3  of olefin resin serve to keep the filter  50  corrugated firmly in place within the filter frame. Thus, a given distance between the two adjacent ridges remains maintained. 
         [0043]    The number of the support lines  3  of olefin resin is not limited to 3 (three). The support lines  3  of poly olefin resin, ploy ethylene resin, or poly propylene resin may be formed on the filter  50 . 
         [0044]    One end of each of the support lines is extended to one-half to two-thirds (included) of width of one outermost inclined surface of the filter  50 , which is defined by both the one outermost ridge on the filter  50  and the one end of the filter  50 , and the other end of each of the support lines  3  is extended to one-half to two-thirds (included) of width of the other outermost inclined surface of the filter  50 , which is defined by both the other outermost ridge on the filter  50  and the other end of the filter  50 . 
         [0045]    Olefin resin is heat-resistant and chemical-resistant. This permits the support line  3  of olefin resin to keep a distance between the adjacent ridges  1  constant at extreme temperatures and conditions. 
         [0046]      FIG. 5  is a front view of a portion of the filter assembly as shown in  FIG. 2 .  FIG. 6  is a perspective view of a mold for casting the filter assembly as shown in  FIG. 2 . 
         [0047]    As shown in FIGS, when the filter frame  40  is made of urethane resin, the filter  50  is combined with the filter frame  40 , with all edges of the filter  50  being inserted into the filter frame  40 . 
         [0048]    Molten urethane resin  41  is poured into the mold  60  to form the filter frame  40 . At this point, the filter  50  is combined with the filter frame  40 , with all edges of the filter  50  being inserted into the filter frame  40 , in the following manner. 
         [0049]    As shown in  FIG. 6 , molten urethane resin  41  is poured into a rectangular pocket  61  in the mold  60 . A first side of the filter  50  is immersed in the molten urethane resin  41  in the rectangular pocket  61  in the mold  60 , to a given depth. The first side of the filter  50 , when the molten urethane resin  41  is hardened, is removed from the rectangular pocket  61 . 
         [0050]    Molten urethane resin  41  is poured into the rectangular pocket  61  in the mold  60 . A second side of the filter  50  is immersed in the molten urethane resin  41  in the rectangular pocket  61  in the mold  60 , to a given depth. The second side of the filter  50 , when the molten urethane resin  41  is hardened, is removed from the rectangular pocket  61 . 
         [0051]    Molten urethane resin  41  is poured into the rectangular pocket  61  in the mold  60 . A third side of the filter  50  is immersed in the molten urethane resin  41  in the rectangular pocket  61  in the mold  60 , to a given depth. The third side of the filter  50 , when the molten urethane resin  41  is hardened, is removed from the rectangular pocket  61 . 
         [0052]    Molten urethane resin  41  is poured into the rectangular pocket  61  in the mold  60 . A fourth side of the filter  50  is immersed in the molten urethane resin  41  in the rectangular pocket  61  in the mold  60 , to a given depth. The fourth side of the filter  50 , when the molten urethane resin  41  is hardened, is removed from the rectangular pocket  61 . 
         [0053]    In this manner, the filter frame  40  is formed that encloses the first, second, third, and fourth sides of the filter  50 . This permits not only a seamless connection between the filter frame  40  and filter  50 , but also a stable support of the filter  50  by the filter frame  40 , without having to use an adhesive agent. 
         [0054]    The filter frame  40  may be made of aluminum or stainless steel. In this case, the filter frame  40  and the filter  50  are attached to each other with an adhesive agent. 
         [0055]      FIG. 7  is an expanded, perspective view of a portion of the filter assembly as shown in  FIG. 3 .  FIG. 8  is a picture of a dissembled portion of the one embodiment of the filter according to the present invention. 
         [0056]    As shown in  FIGS. 7 and 8 , the filter  50  according to one embodiment of the present invention, includes a first element  51 , a second element  52 , a third element  53 , and a fourth element  54 . 
         [0057]    The fourth, third, second, and first elements  54 ,  53 ,  52 , and  51  are placed on one right after the other, in this order. That is, the first (front) element  51  makes up a front face of the filter  50  and the fourth element (rear)  54  makes up a rear face of the filter  50 . And the second and third elements  52  and  53  are placed between the first and fourth element  51  and  54 . The first and fourth elements  51  and  54  are outermost ones. The first, second, third, and fourth elements  51 ,  52 ,  53 , and  54  are attached to one right after the other, with an adhesive agent. 
         [0058]    The adhesive agent includes EVA (ethylene vinyl acetate) resin. 
         [0059]    The first element  51  is made from a non-woven fabric. The first element  51  is manufactured using a spun bond method which is cost-effective. As a result, the first element  51  has excellent strength and durability characteristics. 
         [0060]    The first element  51  has pores in the body. The pores, each with a different size, are irregularly arranged. The size of the pore should be within a given tolerance. Mean size of the pores in the first element  51  may be in a range of 95 to 115 μm (included). 
         [0061]    The first element  51  may be water-proof by coating each of strands of fiber making up the first element  51 , with a waterproof agent. The waterproof agent, used in coating the strands of fiber making up the first element  51 , includes fluorine polymer, emulsifier, tripropylene glycol, polyoxyethylene alkyleter, and water. The waterproof agent has the following component ratio. 
         [0062]    The waterproof agent consists of 28.1 percent mixture of fluorine polymer and emulsifier, 7.7 percent tripropylene glycol, 2.5 percent polyoxyethylene alkyleter, and 61.7 percent water. The strands of fiber making up the first element  51  are coated with the waterproof agent, in the following manner. 
         [0063]    The first element  51  is dipped into a container containing the waterproof agent for a given time and is drawn out of the container. The first element  51  is then pressed by a pressure roller to squeeze the surplus waterproof agent out of the first element  51 . Lastly, the first element  51  is dried with a dryer. The first element  51  may be insect-repellant by coating each of strands of fiber making up the first element  51 , with an insect-repellant agent. 
         [0064]    The insect-repellant agent includes camphor or flavonoid. 
         [0065]    Flavonoid is extracted from a cinnamomum camphora (tree). Flavonoid is extracted from a gingko (tree). 
         [0066]    The first element  51  is dipped into the container containing waterproof agent and insect-repellant agent. As a result, the strands of fiber making up the first element  51  are coated with waterproof agent and insect-repellant agent, at the same time. 
         [0067]    Each of the second and third elements  52  and  53  is made from a non-woven fabric. The second and third elements  52  and  53  are manufactured using a melt blown method. As a result, each of the second and third elements  52  and  53  has pliability, non-permeability, and insulation characteristics. 
         [0068]      FIG. 9  is a picture of an expanded surface of a second or third element making up the filter as shown in  FIG. 8 . 
         [0069]    As shown in  FIG. 9 , each of the second and third elements  52  and  53  has pores. The pores, each with a different size, are irregularly arranged. The size of the pore should be within a given tolerance. Mean size of the pores in the second and third elements  52  and  53  may be in a range of 5 to 20 μm (included). 
         [0070]    The second and third elements  52  and  53  are water-permeable. 
         [0071]    The fourth element  54  is made from a non-woven fabric. The fourth element  54  is manufactured using a needle punch method. The thickness of the fourth element  54  is determined by adjusting either the number of times that the needle punches the non-woven fabric, or the size of the needle. 
         [0072]    The fourth element  54  has pores. The pores, each with a different size, are irregularly arranged. The size of the pore should be within a given tolerance. Mean size of the pores in the fourth element  54  may be in a range of 40 to 60 μm (included). 
         [0073]    The fourth element  54  may be water-proof by coating each of strands of fiber making up the fourth element  54 , with a waterproof agent. 
         [0074]    Like the one with which to coat the strands of fiber making up the first element  51 , the waterproof agent with which to coat the strands of fiber making up the fourth element  54  includes fluorine polymer, emulsifier, tripropylene glycol, polyoxyethylene alkyleter, and water. The waterproof agent has the same component ratio as the one used in coating the strands of fiber making up the first element  51 . 
         [0075]    The strands of fiber making up the fourth element  54  are coated with the waterproof agent, in the same manner as the strands of fiber making up the first element  51 . 
         [0076]    The fourth element  54  may be insect-repellant by coating each of strands of fiber making up the fourth element  54 , with an insect-repellant agent. 
         [0077]    The insect-repellant agent with which to coat the strands of fiber making up the fourth element  54  has the same components as the ones with which to coat the strands of fiber making up the first element  51 . 
         [0078]    The strands of fiber making up the fourth element  54  are coated with the insect-repellant agent in the same manner as the strands of fiber making up the first element  51 . 
         [0079]    The filter  50  according to another embodiment of the present invention includes two or more first element  51 , a second element  52 , a third element  53 , and two or more fourth element  54 . The filter  50  according to another embodiment of the present invention includes a first element  51 , two or more second element  52 , a third element  53 , and a fourth element  54 . 
         [0080]    The filter  50  according to another embodiment of the present invention includes a first element  51 , a second element  52 , two or more third element  53 , and a fourth element  54 . Operation of the cooling apparatus equipped with the filter assembly FA according to the present invention is now described. 
         [0081]    As shown in  FIG. 1 , the motor  30  rotates the fan  20 . The fan  20  pulls outside air through the filter  50 , installed into the inlet  11 , into the housing  10 . Fine dust particles and moisture are removed from the outside air passing through the filter  50 . Thus, clean outside air is introduced into the housing  10 . 
         [0082]    Moisture and fine dust particles are removed from the outside air passing through the filter  50  in the following manner. 
         [0083]    Outside air passes through the first, second, third and fourth elements  51 ,  52 ,  53 , and  54 , in this order. Moisture is removed from the outside air passing through the first element  51 . Fine dust particles are removed from the outside air passing through the second and third elements  52  and  53 . 
         [0084]    According to experimental data, 99.99% or more of 0.3 μm fine dust particles are removed from the outside air passing through the second and third elements  52  and  53 . 
         [0085]    Moisture is further removed from the outside air, which passed through the first, second, and third elements  51 ,  52 , and  53 , passing through the fourth element  54 . 
         [0086]    Outside air, after introduced into the housing  10 , picks up heat produced by the electronic device E, and then passes through the filter  50 , inserted into the air outlet  12  in the housing  10 , to carry away the heat. This makes the electronic device E cooler. 
         [0087]    The filter  50  inserted into the air outlet  12  in the housing  10  prevents outside air with moisture and fine dust particle from being introduced into the housing  10 . 
         [0088]    The temperature of the electronic device E decreases with an amount of outside air introduced into the housing  10 . The amount of outside air depends on the rotation speed of the fan  20 . The fan  20  commonly rotates to maintain the electronic device E at the temperature of less than 65° C. 
         [0089]    A configuration of the filter  50  (i.e., the stack of four elements of non-woven fabric) not only allows for smooth introduction of outside air into the housing  10 , but also prevents production of static electricity. The filter  50  is easy to manufacture. 
         [0090]    The waterproof first and fourth elements  51  and  54  of the filter  50  allows for effective removal of moisture from outside air passing through them. The second and third elements  52  and  53  of the filter  50  allows for effective removal of fine dust particles from outside air passing through them. 
         [0091]    The flying insect may be drawn to the filter  50 , thereby preventing smooth flow of outside air into the housing  10 . The insect-repellant first and fourth element  51  and  54  of the filter  50  keeps an insect away from the filter  50 . 
         [0092]    As the present invention may be embodied in several forms without departing from the spirit or essential characteristics thereof, it should also be understood that the above-described embodiments are not limited by any of the details of the foregoing description, unless otherwise specified, but rather should be construed broadly within its spirit and scope as defined in the appended claims, and therefore all changes and modifications that fall within the metes and bounds of the claims, or equivalents of such metes and bounds are therefore intended to be embraced by the appended claims.