Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
  • B65D—CONTAINERS FOR STORAGE OR TRANSPORT OF ARTICLES OR MATERIALS, e.g. BAGS, BARRELS, BOTTLES, BOXES, CANS, CARTONS, CRATES, DRUMS, JARS, TANKS, HOPPERS, FORWARDING CONTAINERS; ACCESSORIES, CLOSURES, OR FITTINGS THEREFOR; PACKAGING ELEMENTS; PACKAGES
  • B65D88/00—Large containers
  • B65D88/34—Large containers having floating covers, e.g. floating roofs or blankets

Definitions

• the invention relates to a method for the installation of a floating roof structure in a dosed liquid storage tank and further it relates to a floating roof obtained thereby.
• Storage tanks for liquid products may have a diameter from e.g. 8 to nearly 88 meters and in the latter case enormous volumes of liquid vapour must be discharged to the open air. This encounters extensive environmental problems because mostly such stored volatile liquids dangerously affect the breathing of human beings and animals.
• Metal floating roof structures are known which may sink down as a result of liquid movements and/or leakage, resulting again In the creation of a level of liquid. Also there do exist floating roofs which are underneath covered with an aluminium foll yet giving rise to locally created levels of liquid, causing the aforementioned disadvantages. Moreover a floating tank roof structure must be sufficiently strong to be usable as a building site for carrying out repair activities.
• a floating roof structure also serving as a building floor may be installed in a closed storage tank for liquid, which roof is composed of a number of interconnected synthetic modules thereby carrying out the following steps:
• the roof structure is provided with operational means such as: i. a manhole in order to carry out activities underneath the roof structure;
• roof structure supporting legs which may or may not be adjustable
• the longitudinal and traverse seams between adjacent modules of the working floor for the roof structure are sealed off at the bottom side of the roof structure by means of self-adhesive tape thereby forming a totally flat surface, whereafter for the prevention of gas and air inclusions, the seam slit is further fitted up with synthetic material of the skin material of the sandwich module, the self adhesive tape being removed or not after hardening;
• the flexible tank wail seal is thereafter mounted to the circumferential edge of the roof structure.
• the floating roof structure is built up of sandwich module boards and traverse frame profiles, characterized in that a traverse frame profile has a polygonal vertical cross section and is composed by two preferably rectangular tubular profiles, one on top of the other, particularly a lower square tubular profile and on top of it an upper rectangular tubular profile, resting upon its short rectangular side.
• the length of a cut-off profile preferably amounts 1,000 mm whereas the total integral cross section of the traverse frame profile amounts to 50 x 50 and 50 x 30 square mm respectively.
• the stiffness of the built up tank roof structure may be efficiently obtained while using a standard sandwich module having a width of 500 mm, a length of 6,000 mm and a thickness of 50 mm.
• a sandwich module In order that a sandwich module possesses sufficient rigidity it may be provide in a direction perpendicular to its longitudinal axis with integral insert pieces of screwable material at regular distances preferably made of hard screwable polylamlnated wood (Multiplex), which pieces are incorporated in the foamed core material for the fixind of screws and suchlike fixing elements in and to the sandwich module.
• Multiplex hard screwable polylamlnated wood
• the tank roof structure is entirely flat except for the presence of a required manhole flange and various
• the entire roof structure is equally supported on various locations wlth respect to the bottom of the storage tank and all provisions are available to make the operational use of the tank roof structure profitable, thereby excluding any disadvantages which inherently affect existing floating tank roof structures.
• air inlet and air discharge means for a tank roof structure consisting of a potshaped housing, having a number of parts, provided with at least one fixing flange for connecting it with the opening in a sandwich module and a cup shaped cover of the housing being provided with a number of air inlet and discharge openings respectively which are covered by a flexible non-return valve, a vertically movable bar being centrally petitioned in the cover, which bar is provided at its upper end above the cover with an eyelet for connection to a cable and within the housing under the cover and perpendicular thereto said bar is provided with a number of closed discs, each having an outer circumferential downwardly directed cupshaped edge, whereas the inner side of said housing is provided with a number of corresponding downwardly directed funnel-shaped concentric baffles, in such a way that vapors passing through said means are forced to escape via this labyrinth seal.
• a flat magnet is provided having horizontally and centrally respectively in at least two mutually perpendicular directions a number of anti-tilting elements, one and the other such a way that a possible tilting point or tilting Ine with respect to said fe located substantially far away and outwardly from the utmost borderline of the circumferential edge if the permanent magnet which holds to the bottom of the storage tank.
• Fig. 1 is a schematic upper view of a floating tank roof structure aocordlng to the invention
• Fig. 2 shows schematically and in cross section the location of the tank roof structure which is supported upon the bottom of the tank by means of a great number of support legs;
• Fig. 3 shows separately a synthetic module as part of the flat surface of the tank roof
• Fig. 4 te partially a cross section through a preferred embodiment of the tank roof structure taken at the sealing off against the wall of the tank;
• Fig. 5 also shows a partial cross section of another preferred embodiment of a tank roof structure as shown in Fig. 4;
• Fig. 6 is a cross section of the traverse frame profiles which are applied for to render the required stiffness and strongness to the tank roof structure;
• Fig. 7 shows a special anchoring structure to fix the position of the floating tank roof
• Fig. 8 is a cross section of a bushing in the tank roof in use for a dipstick gauging tube and for anti-rotation cables;
• Fig. 9 is a cross section of a sampling device provided for in the tank roof, provided with a star-shaped flexible non-return valve;
• Fig. 10 is a liquid vapour-overpressure drain valve provide with a labyrinth seal avoiding liquid to arrive upon the tank roof;
• Fig. 11 is a cross section of the manhole structure for the tank roof.
• the method basically consists in the composition of on entire floating tank roof 1, shown in Fig. 1 and 2, which has a flat synthetic board covering 2 having floating properties.
• the strongness and the stiffness of the synthetic covering 2 is obtained by interconnecting a great number of sandwich modules 3 to form a flat surface while using traverse frame profiles 4, each of which is constituted by a number of tubular, preferably rectangular profile which are traversally coupled to the sandwich modules 3
• traverse frame profiles 4 each of which is constituted by a number of tubular, preferably rectangular profile which are traversally coupled to the sandwich modules 3
• a scaffolding Prior to building up a floating tank roof 1 at the Inside of a storage tank 5 there is erected upon the bottom 7 of the tank, at a workable level of e.g. 80 cm, a scaffolding having a flat upper surface (not shown here) upon which the sandwich modules 3 are positioned.
• sandwich modules 3 are now horizontally positioned according to Fig. 1 and nearby the wal 9 of the tank the sandwich modules 3 are adapted to the rounded shape.
• a foamed core material 10 which is composed from e.g. a flat core of hard foam sandwiched between two glass fiber reinforced outer skins 11. It is obvious that the sandwich module 3 is entirety unsusceptible for affection by the liquid stored in the tank 6; this being important in the event of mechanical damage to the tank roof structure.
• the thickness of the sandwich module 3 is e.g.
• Figs. 4 and 5 show the arrangemert of the traveree frame profiles 4 in a direction perpendicular to the longitudinal axis of the oblong sandwich module 3.
• One tubular profile 5 which has a rectangular cross section, having an overall length of e.g. 100 cm, is bondwtse placed upon a first lower row of tubular profiles 5, see Fig. 6, and it is effective to let the longitudinal seam 12 between adjacent sandwich modules 3 coincide with an abutting seam 12' between the square profiles 5.
• a traverse frame profile 4 is a reversed T-profile composition; dimensions 50 x 50 mm and 50 x 30 mm respectively.
• installation takes place with short standard lengths, at the other hand It simplifies a quick mounting and disassembly respectively.
• an endless sealing tip 16 is liquid tight connected by means of a colar 17 to the edge of the tank roof 1 and the position of the tank roof 1 1s defined also by a spring element 18 the one end 19 of which is connected to a seal lip 16 whereas the other end
• Fig. 5 shows another wall seal in cross sectional view, consisting of a flexible bumper 16' which is fixed to the tank roof 1 by means of a distance holding device 18'.
• Fig. 7 shows a bushing 22 in the sandwich module 3 for an anchoring cable 23.
• the upper end of this anchoring cable 23 is fixed to the fixed roof of the storage tank 6 and its lower end 24 is connected to the upper side of a permanent magnet 26 by means of a spring 25, it is the purpose to anchor the magnet 26 to the bottom 7 of the tank, the presence of a number of anti-rotation cables 23 thereby holding the position of the floating tank roof 1.
• the magnet 26 is provided with protrusions 27 e.g.
• FIG. 8 another bushing 28 is shown for a fixed gauging tube (not shown here).
• a flexible collar or cup 29 is clamped between a fixed flange 30 which b bolted by means of bolts 14' around an opening in the tank roof 1 and a removable flange 31 so that the tank roof 1 can move in an upward and downward direction with respect to the fixed gauging tube. If necessary, the whole tank roof 1 may be sunk for half of its thickness into the liquid without affecting its effectiveness.
• a sampling device Fig. 9, consisting of a funnel-shaped mouth 33 for receiving and centering a bottle shaped container (not shown) which is lowered by means of a star- shaped cut flexible valve 34 to sample liquid from the tank content.
• the annular protruding edge 35 at the lower side of the funnel-shaped mouth 33 rests upon and is guided respectively in u tubular passage 36, provided with a flange 37 and a counter flange 38 for its attachment to the opening bi the tank roof 1.
• a number of air openings At the level of the flange 37 there are provided in the tubutar widened portion a number of air openings.
• the Valve 34 is attached to the throat of the funnel-shaped mouth 33 by means of a hinge 39 and can be opened by means of a cable 40.
• the other cable end is connected to a hook 41 whioh is adjustably in its height attached to the tank roof 1.
• the valve 34 is automatically opened in the event that the lower end of the hook 41 (not fully shown) is running up against a stop, e.g. the bottom 1 of the tank.
• a discharger 32 consists of a pot shaped housing 42 which is downwardly attached to a tubular passage 45 provided with attachment flanges 43 and 44 respectively and connected to the tank roof 1.
• the passage 45 has air openings 46 and it diverges downwardly to a funnel 47.
• the housihg 42 is covered by a cup-shaped lid 48 which is provided with passage ways 49 which are closabie by means of a flexible non-return vaive
• a central rod 51 having an eyelet 53 can be operated by a cable 23' from the upper side and so be lifted or closed.
• Attached to the rod 61 and to the housing 42 are cooperating labyrinth baffles and discs 64 and 66 respectively which obstruct the escape of vapour. To enable a fast escape however the lid 48 is operated by means of the cable 23'.
• Fig. 11 shows details of a manhole.
• the manhole cover 66 rests upon a tubular collar flange 57 circumferential edge of the manhole 8.
• the flange is attached by means of screws 14' screwed in the hard polylaminated (Multiplex) material within the sandwich module 3.
• a discharger 32 see Fig. 2
• further handgrips are provided at the upper and bottom side respectively of the manhole cover 66.
• Fig. 2 schematically shows the adjustable support legs 60 which are guided by and attached to the tank roof 1 by means of tubular guidlngs 61.
• Such support legs may have a fixed length and are attached to the tank roof 1 by means of a tubular guiding 61 or the support tegs 60 and their guidlngs 61 are provided of adjustable locking devices, known per se.
• the floating tank roof 1 is of very light construction and it has a high floating power and, by its enormous own rigidity resulting from the use of sandwich modules and low traverse frame profiles, is also an ideal building floor for carrying out maintenance activities.
• the smooth surface underneath it prevents all existing disadvantages with known tank roofs.
• Fig. 1 the simple and systematic building up of the tank roof structure by the new method is made visible.
• the modular arrangement makes it possible to make tank roofs of different dimensions having the same favorable floating power.
• the use of the sandwich structure having a hard outer skin make no longer a problem of possible damages and their quick repair.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Filling Or Discharging Of Gas Storage Vessels (AREA)

Priority Applications (4)

Applications Claiming Priority (2)

Publications (1)

Family

ID=19856799

Family Applications (1)

Country Status (9)

Cited By (8)

Citations (9)

• 1990
  • 1990-03-22 NL NL9000684A patent/NL9000684A/nl not_active Application Discontinuation
• 1991
  • 1991-03-22 CA CA002057921A patent/CA2057921A1/en not_active Abandoned
  • 1991-03-22 EP EP91908878A patent/EP0473778A1/en not_active Withdrawn
  • 1991-03-22 JP JP3508544A patent/JPH05504924A/ja active Pending
  • 1991-03-22 WO PCT/NL1991/000044 patent/WO1991015418A1/en not_active Ceased
  • 1991-03-22 KR KR1019910701658A patent/KR920701015A/ko not_active Withdrawn
  • 1991-03-22 FI FI915467A patent/FI915467A0/fi not_active Application Discontinuation
  • 1991-03-22 AU AU77811/91A patent/AU7781191A/en not_active Abandoned
  • 1991-05-16 TW TW080103792A patent/TW221684B/zh active

Patent Citations (9)

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