Membrane cover having a protective layer to prevent deterioration of UV stabilizers therein

a membrane cover and protective layer technology, applied in the field of membrane covers, can solve the problems of deterioration of uv stabilizers in the membrane cover, loss of uv protection, and inability to address the problem of uv stabilizer deterioration in the membrane cover
US20050217204A1Inactive Publication Date: 2005-10-06GEOMEMBRANE TECH
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Patent Information

Authority / Receiving Office
US · United States
Patent Type
Applications(United States)
Current Assignee / Owner
GEOMEMBRANE TECH
Publication Date
2005-10-06
Estimated Expiration
Not applicable · inactive patent

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Abstract

The membrane structure according to the present invention has a top layer containing three plies. The top ply has UV stabilizers embedded therein; the bottom ply has stretch-resistant elements embedded therein; and the middle ply contains a co-extruded polyvinylidene chloride barrier film for example, for protecting the top ply against bio-gas infiltrations therein. In another aspect, the top and bottom plies containing polyethylene for protecting the middle ply from the weather and from corrosive environments under the membrane cover. In yet another aspect, the membrane structure has two foam layers affixed to the bottom ply. Each foam layer is made of juxtaposed strips of semi-rigid, closed-cell, polyethylene foam; wherein each strip in one foam layer is laid astride the adjoining edges of a pair of strips in the other foam layer. The strips of foam are bonded together and to the undersurface of the bottom ply by strips of fused polyethylene.
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Description

FIELD OF THE INVENTION

[0001] This invention pertains to membrane covers for industrial, municipal and agricultural reservoirs and lagoons, and more particularly, it pertains to a floating membrane cover having a top layer, UV stabilizers in the top layer, a structural layer in contact with the liquid surface of a reservoir and a bio-gas-impermeable shield laid between the top layer and the structural layer. BACKGROUND OF THE INVENTION

[0002] It has been noted that the useful life of a membrane cover covering a wastewater reservoir in a warm-weather region where the cover is exposed to much sunlight, is somewhat reduced as compared to covers installed in colder climates. After analysing several installations of different ages and in different environmental conditions, it was understood that the porosity of a membrane cover increases with temperature and that the bio-gases generated under a membrane cover slowly seep or migrate upward through the membrane layers and react with the me...

Claims

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
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