Abstract:
A jacket ( 1 ) is shaped to enclose at least partially a liquid storage vessel ( 2; 200 ), the jacket comprising a skin ( 5 ) arranged as a plurality of folds ( 20 ) which are capable of opening out to permit expansion of the jacket in the event of liquid escaping from the storage vessel, securing means ( 9   a   , 9   b   , 10   a   , 10   b   , 13   a   , 13   b   , 14   a   , 14   b   ; 35 ) are provided to secure the upper part ( 32 ) of the jacket in position with respect to the vessel and to maintain the upper part of the jacket in position in the event of liquid escaping from the vessel. The jacket may be fitted to existing oil tank or new oil tank installations, or may be used with cold or hot water tanks.

Description:
This is a United States national stage application of International application No. PCT/GB00/00667, filed Feb. 28, 2000, the benefit of the filing date of which is hereby claimed under 35 U.S.C. §120, which in turn claims the benefit of British application No. 9904508.0, filed Feb. 27, 1999, the benefit of the filing date of which is hereby claimed under 35 U.S.C. §119. 
    
    
     FIELD OF THE INVENTION 
     This invention relates to jackets which are to be used primarily around storage vessels containing liquid to retain any liquid which has leaked from the vessel. 
     BACKGROUND OF THE INVENTION 
     It is known at present to provide a bund around storage vessels, which contain oil for example. Such bunds conventionally comprise a brick wall which surrounds the storage vessel so as to contain any liquid which has leaked from the vessel. Such bunds, however, can be space consuming and result in the creation of a permanent structure, which may be undesirable. 
     BRIEF SUMMARY OF THE INVENTION 
     According to a first aspect of the invention there is provided a jacket which is adapted to enclose at least partially a liquid storage vessel, the jacket comprising a skin arranged as a plurality of folds which are capable of opening out to permit expansion of the jacket in the event of liquid escaping from said storage vessel, characterised by securing means adapted to secure the upper part of the jacket in position with respect to the vessel and to maintain the upper part of the jacket in position in the event of liquid escaping from the vessel. 
     The inventive jacket may be fitted, for example, to domestic and commercial oil tanks made of steel or plastics. Alternatively it may be fitted to a water tank or hot water cylinder. 
     Preferably the folds in the skin are arranged, in use, to extend substantially horizontally, the plurality of folds being vertically spaced-apart from one another, and preferably such folds are retained in position by a plurality of vertically extending resilient members. 
     The jacket preferably comprises a rigid base tray, the lower margin of the skin being sealably attached to the upstanding walls of the tray. 
     The tray is preferably provided with an outlet through which any leaked liquid retained by the jacket can be drained. 
     The jacket preferably comprises a cover which is adapted to fit the upper end of the storage vessel, and preferably the cover overlaps with the upper margin of the skin and is external thereto. Such a cover can provide protection against ingress of rainwater for an outside storage vessel. 
     The securing means may be positioned beneath the cover or/and the upper margin of the skin may be attached to the cover by the securing means. 
     The invention also comprises a hot water cylinder fitted with a jacket in accordance with the first aspect of the invention. 
     A hot water cylinder and jacket assembly may be provided with a float valve adapted to sense the level of any leaked water collecting in the space between the cylinder and the jacket, and operative to turn off a water supply to the cylinder. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Some embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings in which: 
     FIG. 1 is a front elevation of a jacket and storage vessel assembly, 
     FIG. 2 is a vertical cross-sectional view of the jacket and storage vessel assembly of FIG. 1 taken on line A—A of FIG. 3, with the top cover in position, 
     FIG. 3 is a plan view of the jacket and storage vessel assembly of FIG. 1 with the top cover removed, 
     FIG. 4 is a plan view of the top cover of the jacket of FIG. 1, 
     FIG. 5 is a schematic front elevation of the jacket and storage vessel assembly of FIG. 1 in which the storage vessel has ruptured and the jacket is containing the liquid which has escaped from the vessel, 
     FIG. 6 is a schematic perspective view of the jacket and storage vessel assembly shown in FIG. 2, 
     FIG. 7 is a perspective view of the jacket and storage vessel assembly of FIG. 1 prior to installation, 
     FIG. 8 is a schematic side view of a hot water cylinder of the direct type fitted with a jacket in accordance with the invention, the jacket being shown in its normal unexpanded condition, and 
     FIG. 9 is a view similar to FIG. 8 of a hot water cylinder of the unvented direct type fitted with a jacket in accordance with the invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     FIG. 1 shows a jacket  1 , which encloses a rigid rectangular liquid storage vessel  2 . The jacket  1  comprises a rigid base tray  3  in which sits the base of the storage vessel  2 , and a skin  5  which comprises four upwardly extending walls  5   a ,  5   b ,  5   c  and  5   d.  The lower margins of the walls  5   a ,  5   b ,  5   c ,  5   d  are sealingly attached to respective upstanding peripheral walls  3   a ,  3   b ,  3   c  and  3   d  of the base tray  3 . 
     The skin  5  is arranged as a plurality of folds  20  defined by a plurality of vertically spaced, substantially horizontal, parallel fold lines. The folds  20  are gathered into columns  21  by means of resilient cords  22  which extend up from the lower margin of the skins and are attached to the folds  20  at regular vertically spaced-apart intervals. Folds formed in the skin  5  may alternatively be arranged to extend vertically. The materials of the skin  5  and tray  3  are chosen to be impermeable to the liquid held in the storage vessel  5 . 
     Each wall  5   a,    5   b ,  5   c  and  5   d  extends upwards towards the top of the storage vessel  2 , there being one wall of the skin  5  for each peripheral wall of the storage vessel  2 . 
     Resilient securing straps  9   a ,  9   b ,  10   a ,  10   b ,  13   a ,  13   b , and  14   a  and  14   b  are disposed around the skin  5  and extend up towards the top of the storage tank. The straps  9   a ,  9   b ,  10   a ,  10   b ,  13   a ,  13   b  and  14   a  and  14   b  are attached to the lower margin of the skin  5  and to the upper margin of the skin  5 , in the latter case at points  9   a ′,  9   b ′,  10   a ′,  10   b ′,  13   a ′,  13   b ′ and  14   a ′,  14   b ′. The corner straps  9   a  and  9   b  and  10   a  and  10   b  are attached at their free ends to fasteners  12  and  6  respectively. The fasteners  6  and  12  are then connected by means of a horizontal strap  11  which runs longitudinally of the storage vessel  2  and passes through said fasteners. 
     The free ends of straps  13   b  and  14   b  are attached to fasteners  7  and  8  respectively, whereas the free ends of straps  13   a  and  14   a  are fed through fasteners  7  and  8  respectively. The straps  13   a,    13   b,    14   a  and  14   b  thus pass across the width of the storage vessel  2 . To enclose a storage vessel within the jacket  1 . the upper margin of the skin  5  is brought up against storage vessel  2  by pulling on the free ends of the straps  11 ,  13   a  and  14   a.    
     FIG. 4 shows a cover sheet  15  which fits onto the top of the storage vessel  2 , the cover sheet  15  is provided with eight holes  16   a-   16   h  which are disposed so as to be substantially in register with the points  9   a′ ,  9   b′,    10   a ′,  10   b ′,  13   a ′,  13   b ′,  14   a ′ and  14   b ′. The cover sheet  15  is of slightly greater dimensions in plan than the rectangular top of the storage vessel  2  so as to overhang the top, at  15 ′, FIG.  5 . to protect the vessel  2  from the weather when the vessel  2  is positioned outdoors. The cover sheet is attached to the top of the storage vessel  2  by straps  16   a′-   16   h′  which are provided at points  9   a ′,  9   b ′,  10   a ′,  10   b ′,  13   a ′,  13   b ′,  14   a ′ and  14   b ′ and which pass through respective holes  16   a - 16   h  and are turned down to be attached to fasteners (not shown) provided on respective straps  9   a ,  9   b ,  10   a ,  10   b ,  13   a ,  13   b ,  14   a  and  14   b . Apertures  26  and  27  are provided in the cover sheet  15  to accommodate the inlet  24  and the vent  25 . Once secured, the cover sheet prevents the ingress of rain into the space  17  which lies between the storage vessel  2  and the skin  5 . The vent  25  and the inlet  24  may be provided with detachable caps which fit over and are secured to said vent and said inlet. 
     The skin wall  5   d  comprises an elongate transparent window  19  which extends from the lower margin of the wall  5   d  up towards the cover sheet  15 . 
     The base tray can be drilled with a hole saw to accommodate the tank outlet which may be in the centre or side of the tray. 
     The base tray wall  3   d  is provided with a drainage outlet  4 . The outlet  4  is in communication with the space  17  and said outlet is connected to a drain or an existing overflow system. The outlet  4  may be fitted with a valve. 
     The storage vessel  2  comprises an outlet  18  which is in communication with the liquid inside the storage vessel. The storage vessel further comprises an inlet  24  and a vent  25 . 
     Appropriate sealing is provided around the outlets  4  and  18  where they pass through the base tray wall  3   d.    
     FIG. 7 shows how the jacket assembly can be assembled to a tank  2 . The tank  2  can be lifted by the use of suitable straps  50  attached to lifting poles  51 . The tray  3  can be placed in position, as shown, with the skin  5  folded downwards and outwards of the tray  3 . The tank may then be lowered into the tray  3 , and outlet connections can be made to the tank, the straps  50  and poles  51  removed, and then the skin  5  may be folded upwards and secured into place by use of the securing straps  9   a ,  9   b ,  10   a ,  10   b ,  13   a ,  13   b ,  14   a  and  14   b . The top cover  15  can then be placed in position and secured by passing the strap ends through slots  52 . 
     In use the jacket  1  operates as follows. The jacket  1  is first secured around the storage vessel as hereinbefore described. In the event of rupture of the storage vessel  2  liquid contained in the vessel will begin to pour out into the space  17 . The escaped liquid will then flow from the space  17  and through the outlet  4 . If the rate at which the liquid flows out from the ruptured storage vessel should be sufficiently high then the space  17  will begin to fill with liquid and the folds  20  will open out and the elasticated cords  22  stretch and thus the jacket will begin to expand, as shown schematically in FIG.  5 . It is envisaged that the maximum capacity of the space between the storage vessel and jacket will be approximately 110% of the capacity of the storage vessel. An indication of the quantity of liquid which has escaped from the storage vessel and contained by the jacket is given by viewing the level of escaped liquid in the transparent panel  19 . 
     The inventive jacket  1  can advantageously be designed to fit any shape or size of storage vessel. The jacket ensures that any leakage of liquid from the storage vessel is contained or drained to an appropriate location. The inventive jacket may be used around oil tanks or hot or cold water storage tanks, for example. The jacket can be used with a new tank installation or may be assembled to an existing tank, installation, by suitable lifting of the tank. 
     FIGS. 8 and 9 show installations in which jackets in accordance with the invention have been fitted to hot water cylinders  200  as used in houses. Reference numerals corresponding to those used for the jacket of FIGS. 1 to  6  have been applied to corresponding parts in FIGS. 8 and 9. 
     In FIGS. 8 and 9 the base of the cylinder  200  is received within the cup-shaped base tray  3 , and the cylindrical side walls of the skin  5  are folded in a similar manner to the folds shown in FIG. 2, that is, the skin  5  is folded about a series of vertically spaced-apart horizontal fold lines. However, as distinct from the arrangement of FIGS. 1 to  6 , there is no need to provide the resilient cords  22  because the hot water cylinder is generally of smaller size than the storage vessel  2  of FIGS. 1,  2 . 
     Another reason why the jacket  3  of FIGS. 8,  9  will not generally be required to contain such a large volume of liquid as may arise with the jacket of FIGS. 1 to  6  is that, advantageously, I provide an arrangement for turning off the supply of water to the cylinder  200  in the event that a cylinder leakage occurs. A float-operated switch  30  is positioned within the base tray  3 , and is responsive to the level of any water that begins to collect in the tray in the event of a leak. When the water level trips the switch  30 , an electrically-operated shut-off valve  31  is operated to turn off the water supply to the cylinder  200 , thereby minimising the quantity of water that can escape from the cylinder  200 . 
     As shown in FIG. 8, the cylinder  200  has the usual domed-top  201  to the centre of which is attached the hot water outlet  202 . The cover  150  in the FIG. 8 construction is of part-spherical shape to fit the top  201  of the cylinder, and the upper margin  32  of the skin  5 , which terminates at  33 , is secured over the outside of the lower margin  34  of the cover  150 . The external positioning of the upper margin  32  is possible because there is no requirement to deal with rain. 
     The upper margin  32  of skin  5  is secured in place to cover  150  by a series of circumferentially-spaced retaining straps  35  attached to respective holes provided in the cover  150 . These straps  35  are made sufficiently strong to retain the upper margin  32  in position in the event of a leak causing expansion of the folds of the skin  5 . 
     In the unvented cylinder  200  of FIG. 9, the cylinder  200  is insulated by a rigid foam structure  201  which has a flat top  202 . The cover  150  in this case is made of inverted cup-shape, but otherwise the arrangement for securing the cover  150  in position and supporting the upper margin  32  of the skin is the same as in FIG.  8 . 
     In the FIG. 9 assembly a temperature and pressure relief valve is shown at  36 , and a heating element at  37 . Suitable seals are provided in the jacket at  38 ,  39 ,  40  and  41 . 
     If desired, watertight zip fasteners may be provided in regions of the skin  5  to provide access to tank components which may have to be serviced, such as a thermostat.