Solar collector

Abstract

A solar collector for heating and transferring fluids, having an inlet manifold and an outlet manifold through which fluid is respectively transferred into and out of the solar collector; and a plurality of polymer tubes each connected between the inlet and outlet manifolds, the polymer tubes having co-extruded concentric inner and outer tube layers, wherein the outer tube layer is composed of a harder polymer than the inner tube layer.

1 . A polymer tube for use in a solar collector for heating and transferring fluids, the tube having co-extruded concentric inner and outer tube layers, wherein the outer tube layer is composed of a harder polymer than the inner tube layer. 
     
     
         2 . A solar collector for heating and transferring fluids, comprising an inlet manifold and an outlet manifold through which fluid is respectively transferred into and out of the solar collector; and
 a plurality of polymer tubes each connected between the inlet and outlet manifolds, the polymer tubes having co-extruded concentric inner and outer tube layers, wherein the outer tube layer is composed of a harder polymer than the inner tube layer.   
     
     
         3 . A polymer tube as claimed in  claim 1  or solar collector as claimed in  claim 2 , wherein the inner tube layer is the innermost tube layer. 
     
     
         4 . A polymer tube as claimed in  claim 1  or solar collector as claimed in  claim 2 , wherein the outer tube layer lies adjacent the inner tube layer. 
     
     
         5 . A polymer tube as claimed in  claim 1  or solar collector as claimed in  claim 2 , wherein the inner tube layer has a hardness of between 10 Shore A to 90 Shore D, and the outer tube layer has a hardness of between 45 Shore A to 90 Shore D. 
     
     
         6 . A polymer tube or solar collector as claimed in  claim 5 , wherein the inner tube layer has a hardness of between 80 Shore A to 50 Shore D or 30 Shore A to 60 Shore A, and the outer tube layer has a hardness of between 80 Shore A and 50 Shore D or between 70 Shore A and 90 Shore A. 
     
     
         7 . A polymer tube as claimed in  claim 1  or solar collector as claimed in  claim 2 , wherein the polymer tube(s) is composed of a thermoplastic material or of a thermoset material. 
     
     
         8 . A polymer tube or a solar collector as claimed in  claim 7 , wherein when the polymer tube is composed of a thermoplastic material from either the Olefin group or the Polyvinylchloride (PVC) group. 
     
     
         9 . A polymer tube or solar collector as claimed in  claim 7 , wherein the polymer tube is composed of a thermoplastic elastomer, a thermoplastic rubber or a thermoplastic alloy. 
     
     
         10 . A polymer tube or solar collector as claimed in  claim 9 , wherein the thermoplastic elastomer, thermoplastic rubbers or thermoplastic alloys include olefin based polymers comprising an olefin block copolymer or cross linked or non-cross linked polyolefins. 
     
     
         11 . A polymer tube or solar collector as claimed in  claim 8 , wherein where the polymer tube is composed of a material from the PVC group, the material comprises a PVC, a modified plasticised PVC or unmodified plasticised PVC. 
     
     
         12 . A polymer tube or solar collector as claimed in  claim 7 , wherein where the polymer tube is composed of a thermoset material, the material comprises a thermoset elastomer. 
     
     
         13 . A solar collector as claimed in  claim 2 , wherein the polymer tubes are laterally connected via a co-extruded web. 
     
     
         14 . A solar collector as claimed in  claim 13 , wherein the web is made of a hard, rigid material or a soft, flexible material. 
     
     
         15 . A solar collector as claimed in  claim 13 , wherein the web is co-extruded using the same material as that of the inner tube layer, the outer tube layer or using another material. 
     
     
         16 . A solar collector as claimed in  claim 13 ,  14  or  15 , wherein the web is plasticised with elastic properties to give flexibility and allow for variable spacing between the polymer tubes. 
     
     
         17 . A polymer tube as claimed in  claim 1  or a solar collector as claimed in  claim 2 , wherein the tube, or tubes, has a strip co-extruded thereon that covers less than 100% of an outer surface of the tube. 
     
     
         18 . A polymer tube as claimed in  claim 1  or a solar collector as claimed in  claim 2 , wherein the polymer tube comprises an outermost tube layer co-extruded with the inner and outer tube layers. 
     
     
         19 . A polymer tube or a solar collector as claimed in  claim 18 , wherein the outermost tube layer covers less than 100% of the outer tube layer. 
     
     
         20 . A polymer tube or a solar collector as claimed in  claim 17 , wherein the strip covers approximately 25% to 75% of the outer tube layer. 
     
     
         21 . A polymer tube for use in a solar collector for heating and transferring fluids, the tube having at least one tube layer and a co-extruded strip thereon, wherein the strip covers less than 100% of an outer surface of the tube layer. 
     
     
         22 . A polymer tube as claimed in  claim 21 , including an inner tube layer co-extruded inside of the at least one tube layer, and wherein the strip covers approximately 25% to 75% of the at least one tube layer. 
     
     
         23 . A polymer tube for use in a solar collector for heating and transferring fluids, the tube having co-extruded concentric inner and outer tube layers, wherein the outer tube layer is weldable. 
     
     
         24 . A polymer tube as claimed in  claim 23 , wherein the inner tube layer is made of a cross linked polymer. 
     
     
         25 . A polymer tube as claimed in  claim 24 , wherein the inner tube layer is comprised of a moisture curable, silane grafted cross-linked high density polyethylene or a moisture curable, silane grafted cross-linked polyolefin elastomer. 
     
     
         26 . A polymer tube as claimed in  claim 23 , wherein the outer layer is comprised of one of the following: a polypropylene, a polyethylene (LDPE or HDPE), an olefin block copolymer, a thermoplastic elastomer or a thermoplastic rubber. 
     
     
         27 . A polymer tube as claimed in any one of  claims 23  to  26 , wherein the polymer tube has a strip co-extruded thereon that covers less than 100% of an outer surface of the tube. 
     
     
         28 . A solar collector for heating and transferring fluids, comprising an inlet manifold and an outlet manifold through which fluid is respectively transferred into and out of the solar collector; and
 a plurality of polymer tubes as claimed in any one of  claims 23  to  27 , each polymer tube being weldable to either the inlet manifold or outlet manifold, or to both.