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  Insect screen with improved optical propertiesUSPTO Application #: 20060148347Title: Insect screen with improved optical properties Abstract: An insect screen comprising fibers in a warp and fill construction defining openings having a warp dimension and a fill dimension, at least one of the warp and fill dimensions being less than about 0.05 inches and the other of the warp and fill dimensions being larger than about 0.03 inches, the fibers having a diameter of equal to or less than about 0.007 inches. The present invention is an improved insect screen designed to serve the primary purpose of keeping out insects and pests while maximizing visual clarity, light transmission, and airflow. (end of abstract) Agent: Gore Enterprise Holdings, Inc. - Newark, DE, US Inventors: Gordon L. McGregor, Thomas R. Bugg, Thomas P. Kelmartin, Raymond B. Minor, Raymond M. Wnenchak, Thomas B. Schmiedel USPTO Applicaton #: 20060148347 - Class: 442001000 (USPTO) Related Patent Categories: Fabric (woven, Knitted, Or Nonwoven Textile Or Cloth, Etc.), Scrim (e.g., Open Net Or Mesh, Gauze, Loose Or Open Weave Or Knit, Etc.) The Patent Description & Claims data below is from USPTO Patent Application 20060148347. Brief Patent Description - Full Patent Description - Patent Application Claims
RELATED APPLICATIONS [0001] This application is a continuation of U. S. patent application Ser. No. 10/405,104 filed Mar. 31, 2003. FIELD OF THE INVENTION [0002] The present invention relates to screens, and more particularly, to woven insect screens. BACKGROUND OF THE INVENTION [0003] Insect screens have been in use on windows and doors for more than a century. Their intended purpose is to keep out common insects such as flies, moths, mosquitoes, and bees as well as other creatures such as birds and rodents. Insect screens are used for many applications such as windows, doors, patio enclosures, pool enclosures, garage doors, and more. [0004] Insect screens are typically woven from various types of fibers, historically starting from materials such as horsehair and linen. For greater durability, screens evolved to woven wire made of low-carbon steel, however, the steel was known to rust. Bronze, stainless steel, and aluminum wire replaced steel. In the 1970's, screens woven from vinyl (PVC) coated fiberglass fibers were introduced. These screens offered benefits of durability, light weight, ease of weaving, and ease of installation. Vinyl coated fiberglass screens offered a significant improvement over metal screens for ease of installation since common tools can cut and trim the screen materials without leaving sharp wires that can create safety issues. Vinyl coated fiberglass screens have become the industry standard for common insect screens. [0005] Insect screens are primarily designed to exclude insects from an enclosed area while still offering the sensation of the outdoors by transmitting light, sound, and airflow. However, the basic woven fiber construction of a screen will inherently compromise visibility and airflow due to blockage of open area by the fibers. Visual quality can be expressed in terms of both light transmission as well as clarity. Light transmission relates to the quantity of light that passes through the screen. Clarity is a measure of image distortion cause by the interference of the fibers with the visual image as viewed through the screen. Woven screens can also restrict airflow causing reduced ventilation and reduced sensation of "feeling the breeze." [0006] Insect screen constructions have been optimized over the years in order to reach a compromise between excluding most insects and enabling reasonable visibility and airflow. Typically, the most common insect screens used today include 16.times.16, 18.times.14, 18.times.16, and 18.times.18 meshes of plain weave construction. "Mesh" describes the number of openings and fractional parts of an opening per linear inch. With a plain weave, mesh count typically corresponds with the fiber count for number of fibers per inch in the warp and fill. With increased mesh or fiber count, the opening or hole size decreases with fiber diameter remaining constant. In certain geographical regions where small biting midges and sand flies, also known as no-see 'ums, are present, 20 .times.20 mesh screening is recommended to offer exclusion of these insects. However, the tradeoff for excluding small insects, such as midges, is not only a reduction in visual quality but also a reduction in airflow due to the loss of open area from the increased number of fibers. For example, to compensate for the loss of airflow caused by a 20.times.20 mesh screen, it is recommended to double the amount of screen surface area used for ventilation in order to equal the amount of unscreened window normally used; i.e., two screened open windows are required to equal the airflow of one unscreened open window. [0007] Although the term mesh is typically used to describe the relative hole size of woven screening, this term gives no recognition to the diameter of the fiber or wire, and thus the mesh number does not always have a relationship to the size of the hole in the screen. Hole size, aperture, or opening is defined as the dimension between adjacent parallel wires, usually expressed in decimal parts of an inch. It can be calculated using the equation below for each of the warp and fill directions of the screen. Fill is defined as fibers or wires running across the width or short way of the woven cloth during weaving, also referred to as shute and weft. Warp is defined as the fibers of wire running lengthwise during weaving. [0008] Opening=(1/N)-D [0009] N=Wires per inch [0010] D=Wire diameter (inches) [0011] This equation remains accurate for screens woven from wire and fibers where the diameter of the material is unchanging. In the case of PVC coated fiberglass, the coating can melt flow during processing thereby changing the original fiber dimensions. The above formula can be used for these materials as well providing that the fiber diameter is measured in the final state assuming uniform fiber size and parallel fibers. [0012] When comparing screens of different materials and constructions, it is important to make these comparisons using similar opening or hole size dimensions since the opening dimension provides the critical dimension for insect exclusion. Typically, insect screens can be defined by the fiber material, fiber diameter, and weaving construction (mesh or fibers per inch). [0013] In order to understand the opening size commonly used in insect screening, a sampling of various commercial insect screens was compared. The properties and calculated openings are shown in the table below. Calculations in the table assumed mesh and fiber count to be identical. In addition to commercial screens, also included are examples of insect wire screens specified as American National Standards approved by the Insect Screening Weavers Association in 1990 document ANSI/IWS 089-1990. TABLE-US-00001 Wire Warp Fill Dia Opening Opening Supplier Material Mesh (In) (in) (in) Connecticut PVC- 20 .times. 20 0.013 0.0370 0.0370 Screen Works Fiberglass Connecticut PVC- 18 .times. 14 0.013 0.0426 0.0584 Screen Works Fiberglass Wright PVC- 18 .times. 16 0.011 0.0446 0.0515 Screens, LLC Fiberglass American Aluminum 18 .times. 16 0.011 0.0446 0.0515 National Standard American Bronze 18 .times. 14 0.011 0.0466 0.0604 National Standard American Carbon 18 .times. 14 0.009 0.0466 0.0624 National Steel Standard Marco Specialty Galvanized 18 .times. 14 0.009 0.0466 0.0624 Steel Steel Marco Specialty Bronze 18 .times. 14 0.011 0.0466 0.0604 Steel TWP Inc. Stainless 18 .times. 14 0.009 0.0466 0.0624 Steel TWP Inc. Copper 16 .times. 16 0.011 0.0515 0.0515 [0014] As evidenced by the examples in the table, fiber or wire commonly used for window insect screening is known to have diameters ranging from 0.009 to 0.013 inches. It is important to note that the calculated hole width for the fiberglass screens used the indicated wire diameter as opposed to the actual wire diameter in the finished screen. Hole size and open area of PVC coated fiberglass screens typically have values less than the expected values due to flow of the PVC coating. [0015] Various polymeric materials have been used for specialized greenhouse screening. This type of screening is used for the purposes of restricting very small insects and thereby negating the need to use pesticides. These screens are typically woven from small diameter polyethylene and nylon fibers into tight screen constructions to have very small hole sizes of less than 0.02 inches. These screens can be purchased from Green-tek under the names No-Thips and Virus Vector screens. These types of insect screens are not intended for residential insect screen applications because of poor visual clarity characteristics and limited airflow. Furthermore, fiber materials such as polyethylene and nylon are known to have poor UV radiation (sunlight) resistance, which can degrade the fiber strength over time. Thus, polyethylene and nylon screens are typically limited to a lifetime of three years or less. The lifetime of residential screens is expected to be many years, often five, ten, or more. For these reasons, polyethylene and nylon are not used as insect screens for windows, doors, patios, and other residential applications. [0016] Typically, insect screens have either the warp or fill hole dimension to be less than about 0.05 inches in order to exclude most common flying insects, with the other hole dimension being larger than about 0.03 inches in order to offer acceptable airflow, visual clarity, and/or light transmission. In other words, the warp and fill dimension are not both below about 0.03 inches, nor are they both above about 0.05 inches. This hole size range for residential window screening is consistent with products offered and sold as window/insect screen. One example of screen sold for insect exclusion with a hole size larger than 0.05 inches in both the warp and fill dimensions is made of copper wire with a 16.times.16 mesh as described in the table above. This screen uniquely offers a historically accurate aesthetic appeal and does not fall into the hole size ranges depicted by the American National Standards of the Insect Screening Weavers Associations. [0017] It has been recognized that optical attenuation and light distortion of window screens can be undesirable. U.S. Pat. No. 5,139,076 describes a distortion free window screen made from transparent fiber optic cables. It is the intention of this patent to increase the light transmission of the screen while minimizing distortion of the light passing through the fibers. They attempt to accomplish this by using clear, round cross-section, fibers. Although the total light transmission can be improved with clear fibers, distortion and glare will still exist due to reflection and refraction of the light rays through the clear fiber. [0018] Another attempt to minimize the drawbacks of screen see-through visibility is described in U.S. Pat. No. 5,392,835. This patent describes a roll-type retractable insect screen that can be retracted when not in use. This type of technology enables the user to remove the screen from the field of view when not in use so as to provide a clear unobstructed view. [0019] There are long-felt needs associated with current insect screen technology. These include the needs for improvement to optical transmission characteristics and airflow characteristics. In particular, there has been a long-felt need in the industry for an "invisible screen," one that is less visible and hence less obstructive of the view through the screen. It is surprising that using smaller fibers for the screen construction would be effective because more fibers would be needed to provide the same hole sizes, thus not providing any real improvement in visibility. SUMMARY OF THE INVENTION [0020] The present invention is an improved insect screen designed to serve the primary purpose of keeping out insects and pests while maximizing visual clarity, light transmission, and airflow. The present invention employs the use of small diameter fibers woven into an insect screen with standard hole size construction. This construction is a warp and fill construction defining openings having a warp dimension and a fill dimension, at least one of the warp and fill dimensions being less than about 0.05 inches and the other of the warp and fill dimensions being larger than about 0.03 inches. [0021] The present invention provides a non-metallic insect screen woven from fluoropolymer fibers, the fibers being from the fluoropolymer class including ETFE, ECTFE, PTFE, FEP, MFA, PFA, PEEK, and PVDF or hybrids thereof. PVDF fibers are particularly preferred. The invention also provides for metal fibers. [0022] The present invention provides an insect screen woven from fibers with small diameters of about 0.007 inches or less, preferably diameters of about 0.006 inches or less, or more preferable of diameters of about 0.005 inches or less, or most preferably where the diameters are about 0.004 inches or less. Continue reading... Full patent description for Insect screen with improved optical properties Brief Patent Description - Full Patent Description - Patent Application Claims Click on the above for other options relating to this Insect screen with improved optical properties patent application. ###  How KEYWORD MONITOR works... a FREE service from FreshPatents1. Sign up (takes 30 seconds). 2. Fill in the keywords to be monitored. 3. Each week you receive an email with patent applications related to your keywords. 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