Panels for floating covers, floating covers and methods for making them

Abstract

A floating cover ( 12 ) for a liquid storage tank ( 10 ) is made from a plurality of prefabricated sandwich panels ( 30 ). Each panel has an upper glass fibre composite layered portion ( 34 ), a honeycomb layer ( 36 ) the same size as the upper composite layered portion ( 34 ), and a lower fibre glass composite layered portion ( 32 ) that extends around the edges of the honeycomb layer by about 0.1 m. The panels are laid adjacent and abutting each other on a supporting form work, and the gaps above the extended lower layered portion ( 32 ) are filled in with sandwich sections similar to the structural layers of the sandwich panels. The upper parts of the in-fill sections overlap the upper layered portions ( 34 ) of the prefabricated panels by about 0.1 m.

1 . A generally planar buoyant panel for a floating cover for a liquid storage tank, the panel comprising first and second portions in contact with each other, and wherein: the first portion has an extent in the plane of the panel and a first side facing the second portion; the second portion has an extent in the plane of the panel, which extent is less than the extent of the first portion; and the first portion has an exposed portion on said first side.  
   
   
       2 . A panel according to  claim 1 , wherein the second portion has an edge and the exposed portion extends all the way around the edge of the second portion.  
   
   
       3 . A panel according to  claim 1 , wherein the first portion is a laminate structure.  
   
   
       4 . A panel according to  claim 1 , wherein the first portion is a glass reinforced structure.  
   
   
       5 . A panel according to  claim 1 , wherein the second portion is buoyant.  
   
   
       6 . A panel according to  claim 1 , for use with the second portion being above the first portion.  
   
   
       7 . A panel according to  claim 1 , wherein the first and second portions are continuous.  
   
   
       8 . A panel according to  claim 1  further comprising a third portion in contact with the second portion on the other side of the second portion from the first portion.  
   
   
       9 . A panel according to  claim 8 , wherein the third portion has a first side facing the second portion and an extent in the plane of the panel, which extent is the same as or less than that of the second portion.  
   
   
       10 . A panel according to  claim 8 , wherein the third portion has a laminate structure.  
   
   
       11 . A panel according to  claim 10 , wherein the layers of the third portion each have an extent in the plane of the panel and the extent of the layer of the third portion furthermost away from the second portion is less than the extent of the layer of the third portion nearest the second portion.  
   
   
       12 . A panel according to  claim 8 , wherein the third portion is a glass reinforced structure.  
   
   
       13 . A panel according to  claim 8 , wherein the third portion has the same construction as the first portion.  
   
   
       14 . A panel according to  claim 1 , wherein the panel is generally a parallelepiped in the plane of the panel.  
   
   
       15 . A plurality of panels, each as defined in according to  claim 1 , wherein the first portion of each panel has an edge generally orthogonal to the plane of the panel, and the edges of the first portions of adjacent panels abut each other.  
   
   
       16 . A plurality of panels according to  claim 15 , further comprising a plurality of infill portions, each infill portion extending in contact with the exposed portions of two adjacent and abutting panels.  
   
   
       17 . A plurality of panels according to  claim 16 , wherein each infill portion comprises an infill first portion, an infill second portion and an infill third portion, the infill second portion is sandwiched between the infill first portion and the infill third portion, and the infill second portion has the same construction as a panel second portion.  
   
   
       18 . A plurality of panels according to  claim 17 , wherein each infill third portion has the same construction as a panel first portion, inverted.  
   
   
       19 . A plurality of panels according to  claim 17 , wherein in each infill portion: the infill third portion has an extent in the plane of the panels between the infill portion extends and a first side facing the infill second portion; the second portion has an extent in the plane of the panels between which infill panel extends, which extent is less than the extent of the infill third portion; a the extent of the infill third portion not covered by the infill second portion extends onto and in contact with outer surfaces of the panels between which the infill panel extends.  
   
   
       20 . A plurality of panels according to  claim 19 , further comprising a third portion in contact with the second portion on the other side of the second portion from the first portion, wherein the extent of the infill third portion not covered by the infill second portion extends onto and in contact with outer surfaces of the panel third portions panels between which the infill panel extends.  
   
   
       21 . A plurality of panels according to  claim 20 , further comprising a third portion in contact with the second portion on the other side of the second portion from the first portion, wherein the third portion has a laminate structure wherein, the layers of the third portion each have an extent in the plane of the panel and the extent of the layer of the third portion furthermost away from the second portion is less than the extent of the layer of the third portion nearest the second portion, wherein the extent of the infill third portion not covered by the infill second portion is in contact with layers of the panel third portions between which the infill extends, other than the layer of each of those panels furthermost away from the second portion.  
   
   
       22 . A plurality of panels according to  claim 17 , further comprising a third portion in contact with the second portion on the other side of the second portion from the first portion, wherein the third panel has a laminate structure, wherein each infill first portion has the same construction panel third portion without the layer furthermost away from the panel second portion and inverted.  
   
   
       23 . A plurality of panels according to  claim 16 , comprising: one or more drain ports extending from a boundary between said infill portions and one of said panel second portions.  
   
   
       24 . A plurality of panels according to  claim 23 , wherein the first portion is a laminate structure, and, wherein said one or more drain ports extends from a first end thereof flush with an inner most laminate layer of said laminate structure.  
   
   
       25 . A plurality of panels according to  claim 15 , wherein the panels are prefabricated before being laid and joined together where they are to be used.  
   
   
       26 . A plurality of panels according to  claim 16 , further comprising: at least one testing port extending from a boundary between the infill portion and one of the panel second portions to an external surface of one of the panel third portions.  
   
   
       27 . A buoyant cover for a liquid storage tank comprising a plurality of panels according to  claim 15 .  
   
   
       28 . A method of joining a plurality of generally planar buoyant panels together, for use in forming a floating cover, wherein each panel comprises first and second portions in contact with each other, with the first portion of each panel having an extent in the plane of the panel and a first side facing the second portion, the second portion of each panel having an extent in the plane of the panel, which extent is less than the extent of the first portion; and the first portion having an exposed portion on said first side, and wherein the plurality of panels are placed together, with adjacent panels abutting each other, the edges of the first portions of adjacent panels which are orthogonal to the planes of the panels being in contact, the method comprising the step of: inserting infill portions between adjacent panels, the infill portions extending in contact with the exposed portions of adjacent and abutting panels.  
   
   
       29 . (canceled)  
   
   
       30 . A method according to  claim 28 , wherein the plurality of panels are prefabricated off-site before being positioned for joining together.  
   
   
       31 . A method according to  claim 30 , further comprising the step, preceding the inserting step, of roughening exposed surfaces of said panels and cleaning away dust generated thereby.  
   
   
       32 . A method according to  claim 28 , wherein the inserting step comprises: placing a first infill layer over the exposed portions of adjacent and abutting panels; and placing one or more further infill layers over the first infill layer, one at a time.  
   
   
       33 . A method according to  claim 32 , further comprising the step of rolling each infill layer after placing it to remove air.  
   
   
       34 . A method according to  claim 32  or  33 , wherein at least the first infill layer is a non-laminated layer.  
   
   
       35 . A method according to  claim 28 , wherein the panels are securely joined together by people working on just one side of the cover.  
   
   
       36 . A method according to  claim 28  used to produce a buoyant cover for a liquid storage tank comprising a series of panels.  
   
   
       37 . A method according to  claim 28  being a method of forming a floating cover.  
   
   
       38 . A method of constructing a floating cover for a liquid tank from a plurality of panels, wherein the panels are securely joined together by people working on just one side of the cover.  
   
   
       39 . A method of constructing a floating cover for a liquid tank from a plurality of panels, comprising the steps of: placing said plurality of panels on a form work; joining said panels together; and removing said form work; wherein the joining step prior to the removing step is accomplished solely from one side of the cover.  
   
   
       40 . A method for testing the integrity of joints in a floating cover formed by a plurality of panels according to  claim 1  and further comprising: 
 a third portion in contact with the second portion on the other side of the second portion from the first portion; a plurality of infill portions, each infill portion extending in contact with the exposed portions of two adjacent and abutting panels, wherein the first portion of each panel has an edge generally orthogonal to the plane of the panel, and the edges of the first portions of adjacent panels abut each other;    the method comprising: providing at least one testing port extending from a boundary between the infill portion and one of the panel second portions to the external surface of one of the panel third portions; applying a pressure differential between the testing port or one of the testing ports and the outside of the cover; determining if there is a leak between the one testing port or said one of the testing ports and the outside of the cover; and if there is a leak, identifying the leak.    
   
   
       41 . A method of testing according to  claim 40 , wherein applying a pressure differential comprises pumping a gas into the one testing port or said one of the testing ports at a predetermined pressure.  
   
   
       42 . A method of testing according to  claim 41 , wherein said gas is air or nitrogen.  
   
   
       43 . A method according to  claim 40 , wherein applying a pressure differential further comprises sealing said one testing port or said one of the testing ports at a predetermined pressure.  
   
   
       44 . A method of testing according to  claim 43 , wherein determining if there is a leak comprises detecting if there is a change in pressure over time in said one testing port or said one of the testing ports.  
   
   
       45 . A method of testing according to  claim 40 , wherein identifying the leak comprises applying a liquid to portions of said floating cover and observing bubbles formed in the liquid due to a leak.  
   
   
       46 . A method of testing according to  claim 45 , wherein said liquid is a soap solution.  
   
   
       47 . A method of testing according to  claim 40 , further comprising providing a sleeve in said at least one testing port to apply the pressure differential to said at least one testing port.  
   
   
       48 . A method of testing according to  claim 40 , wherein there is a plurality of the testing ports and all but one is sealed as the pressure differential is applied to that one.  
   
   
       49 . A method of joining a plurality of generally planar buoyant panels together, for use in forming a floating cover, wherein each panel is as defined in  claim 1 , and wherein the plurality of panels are placed together, with adjacent panels abutting each other, the edges of the first portions of adjacent panels which are orthogonal to the planes of the panels being in contact, the method comprising the step of: inserting infill portions between adjacent panels, the infill portions extending in contact with the exposed portions of adjacent and abutting panels.