The invention relates to a double layer woven fabric having enhanced water flow and shade properties.
Outdoor pools are often covered with a safety pool cover during the winter months when they go unused. Covering a pool obviates the need to maintain the pool during the winter and protects the pool from the harsh conditions of winter. In use, safety pool covers prevent debris and other foreign objects from entering the pool water and have the necessary strength to prevent a person from falling into the pool.
To prevent algae growth in the pool when covered, it is preferable that pool covers be made from a fabric that prevents as much sunlight as possible from penetrating through the pool cover fabric and into the water below. Traditional pool covers were made from a woven fabric that was coated with a plastic material, such as polyvinylchloride. The resulting fabric was UV resistant to block sunlight and thereby prevent algae growth under the pool cover. However, the cover was also solid in that it was impermeable to fluid and moisture. Mechanical drains were incorporated into the covers else, when it rained, water would collect on top of the cover and the pool cover would tend to sag under the weight of the collected water. However, the drains oftentimes would clog with debris, rendering them ineffective for drainage purposes.
To combat these problems, pool covers began being made from single-layer, woven, uncoated fabrics. These fabrics allowed water to flow through the apertures in the cover and thus prevented water collection on top of the cover. However, because these fabrics were not solid, just as water was allowed to pass through the fabric so too was sunlight. Thus, these fabrics were less capable of blocking sunlight and preventing algae growth.
Traditionally, the more water flow the pool cover allowed (i.e., the more apertures that are provided in the fabric or the larger the size of the apertures provided in the fabric), the less capable the pool cover was at blocking light and thus preventing algae growth. For example, U.S. Pat. No. 6,886,187 to Zell et al. discloses a pool cover made from a single-layer woven fabric that purportedly blocks 100% sunlight. Yet the disclosed fabric provides a flow rate of water of only 0.1 to 5 gallons per square foot per minute. There remains a need for a woven fabric for pool covers that successfully blocks sunlight (preferably up to 100%) and provides for higher water flow through the pool cover.
This invention relates generally to a double layer woven fabric for use in various applications including but not limited to: recreational applications such as, but not limited to, trampolines, sports fields and pool covers; horticultural applications such as, but not limited to, shade use for nurseries, greenhouses, and livestock; industrial applications such as, but not limited to, truck covers, fencing, windscreen containment enclosures, sand blasting, weed control, and industrial debris mats; construction applications such as, but not limited to, filtration, drainage, erosion control, soil reinforcement, secondary reinforcement, paving, soil stabilization, soil separation, earth retaining structures, steepened slopes, embankment stabilization, leachate collection/removal, dewatering bags, and Geotubes® (such as disclosed in U.S. Pat. No. 6,186,701); and agricultural applications. The fabric is particularly well-suited for use as a pool cover, although in no way do the applicants intend for the fabric disclosed herein to be limited to this use only.
One embodiment of the fabric is formed by two layers of fill yarns that are secured together with warp yarns. The fill yarns within at least one layer (and preferably but not necessarily in both layers) have at least two different geometrical shapes. The yarns of one shape help to block sunlight while the yarns of the other shape help to ensure that open channels are formed through the fabric for water flow. Moreover, to the extent that the upper layer of yarns fails to deflect light, the second layer of yarns serves as a back-up layer to help ensure blockage of light. In this way, the fabric provides the desired high shade (preferably blocking at least approximately 99% of light) while allowing high water to flow through the fabric (i.e., between 5-75 gallons per square foot per minute).
Moreover, as shown in
The two layers 12, 14 are preferably woven together with yarn 18. The yarn 18 is preferably, but does not have to be, 400 denier to 1500 denier monofilament yarn. All of the yarns used in fabric 10 are preferably, but do not have to be, made from synthetic polymers and more preferably from polypropylene. While the density of the fabric will depend on its intended properties and uses, the fabric in the warp direction preferably has a density of 20 to 50 threads/inch, and the fabric in the fill or weft direction preferably has a density of 15 to 40 threads/inch.
The resulting fabric 10 may be, but does not have to be, subjected to a calendaring process whereby the fabric 10 is subjected to heat and pressure (such as by running the fabric through a set of heated rollers) to compress and/or flatten yarns 16, 18 and thereby reduce the overall thickness of fabric 10.
The double layer structure of fabric 10 forms essentially a solid sheet of fibers that prevent at least, and preferably more than, 99% of light from passing through the fabric 10 while providing open channels 24 through the fabric 10 for water flow. Any test that accurately measures the amount of light transmitted through fabric 10 may be employed to determine light penetration and resulting shade percentage. For example, a shade box provided with a light source at one end and a light meter at the other end may be used. The fabric to be tested is positioned between the light source and meter, the light source is activated, and the light meter measures the amount of light (R) that penetrates through the fabric and reaches the meter. The amount of shade that the fabric affords can then be calculated based on that measurement (% Shade=100−R). U.S. Pat. No. 5,651,641, the entirety of which is herein incorporated by reference, discloses detailed specifications for measuring light penetration.
As illustrated in
Moreover, the different geometrical shapes of the yarns 20, 22 forming the fabric 10 create open channels 24 for water to flow through the fabric 10. More specifically, the substantially circular shape and size of second yarns 22 ensure that a gap 30 is maintained between the two layers 12, 14. Open channels 24 through which water can flow extend between adjacent yarns 16 in each layer 12, 14 and through the gap 30 between the layers 12, 14. With this double layer fabric construction, water is able to flow at a rate between 5-75 gallons per square foot per minute through the fabric 10, as measured by ASTM standard D4491-99A.
The foregoing is provided for the purpose of illustrating, explaining and describing embodiments of the present invention. Further modifications and adaptations to these embodiments will be apparent to those skilled in the art and may be made without departing from the spirit of the invention or the scope of the following claims.
This application claims the benefit of U.S. Provisional Application No. 60/809,875 filed Jun. 1, 2006, the contents of which are incorporated herein by reference.
Number | Name | Date | Kind |
---|---|---|---|
3405410 | Oldshue | Oct 1968 | A |
3593757 | Haynes | Jul 1971 | A |
3872522 | Bennett et al. | Mar 1975 | A |
4028750 | Gustafsson | Jun 1977 | A |
4137575 | Klaffke et al. | Feb 1979 | A |
4173043 | Vernon | Nov 1979 | A |
4663231 | Girgis et al. | May 1987 | A |
4815499 | Johnson | Mar 1989 | A |
5511536 | Bussey et al. | Apr 1996 | A |
5651641 | Stephens et al. | Jul 1997 | A |
5769131 | Whitlock et al. | Jun 1998 | A |
5795516 | Cho et al. | Aug 1998 | A |
5819811 | Baker et al. | Oct 1998 | A |
5837133 | Natale | Nov 1998 | A |
5887296 | Handwerker | Mar 1999 | A |
5922421 | Perry | Jul 1999 | A |
6047415 | Brown | Apr 2000 | A |
6179013 | Gulya | Jan 2001 | B1 |
6186701 | Kempers | Feb 2001 | B1 |
6418974 | King | Jul 2002 | B1 |
6766542 | Hinsperger | Jul 2004 | B2 |
6836907 | Pesta | Jan 2005 | B1 |
6886187 | Zell et al. | May 2005 | B2 |
6915534 | Johannes | Jul 2005 | B1 |
7059360 | Majaury et al. | Jun 2006 | B1 |
7259113 | Dufresne-Nappert et al. | Aug 2007 | B2 |
20040117903 | Hinsperger | Jun 2004 | A1 |
20040127129 | Luo et al. | Jul 2004 | A1 |
20040177435 | Zell et al. | Sep 2004 | A1 |
20050022297 | Orologio et al. | Feb 2005 | A1 |
20050055760 | Sutton et al. | Mar 2005 | A1 |
20050125887 | Taylor | Jun 2005 | A1 |
20050239354 | Dufresne-Nappert et al. | Oct 2005 | A1 |
20050241056 | Zell et al. | Nov 2005 | A1 |
20060166577 | Rashed | Jul 2006 | A1 |
Number | Date | Country |
---|---|---|
0269070 | Jun 1988 | EP |
Number | Date | Country | |
---|---|---|---|
20070277897 A1 | Dec 2007 | US |
Number | Date | Country | |
---|---|---|---|
60809875 | Jun 2006 | US |