Abstract: A pressure-proof tank for a transport container has an envelope formed by two or more parallel part-cylindrical envelope shells 1, the ends of which are closed by bottoms 2 formed of bottom shells 3. The transition region between the bottom and envelope shells 2, 3, is closed by curved gusset elements 5. The pressure resistance in this transition region is improved by planar rib elements 10 extending through the interior of the tank. The rib elements 10 cooperate with a tension wall 4, which divides the tank in the longitudinal direction, to reduce the effect of surges acting in the transport direction, especially when the tank is partially filled.

Abstract: A field applied lining system for the inside surface of fluid containment vessels is described. The lining system includes a lining joined to the inner walls of a fluid containment vessel, defining an interstitial space between the inner wall of the storage tank and the lining. The lining consisting of a plurality of panels of pre-manufactured Fiber Reinforced Plastic joined to each other. A support structure is placed in the interstitial space, the support structure defining avenues for fluid flow through the interstitial space. One or more conduits are provided between the interstitial space and one or more sampling ports placed at the perimeter of the one or more sampling ports placed at the perimeter of the storage tank, permitting access to the interstitial space and the avenues for fluid flow through the interstitial space.

Abstract: This invention relates to a liquid storage system for storing liquid products, particularly petroleum and its derivatives. An auxiliary dam (1) within a bund defined by a main dam (3) bounds an area (5) around a tank (2) in such a way that the contaminating wastes from the fluids stored in the tank are contained within that area (5).

Abstract: A liquid storage container primarily for manure or other slurry includes a cylindrical wall formed from a plurality of connected panels of corrugated steel to define a generally horizontal top edge and a generally horizontal bottom edge surrounding an area of ground surface inside the wall. The wall is maintained in vertical orientation by a plurality of vertical posts connected to the wall at spaced positions around the wall. Each post is formed by a channel with the open face outward and an inner face bolted to the wall. Each post is adjustably connected to a respective on e of a plurality of ground anchors each having a vertical shaft and a helical flight on the shaft, the shaft and the flight being arranged to be screwed into the ground, each anchor being connected at its upper end by an adjustable screw to a plate attached across the bottom of the post. An impermeable liner lies over the area of ground surface inside the wall and has a skirt portion attached to the wall.

Abstract: A sump has a one-piece body, comprising a hollow base member for collecting fluids leaking from a piping system, the base member having an upper portion and a lower portion. The one-piece body further comprises a hollow riser section having an upper portion defining an opening, and a lower portion, the riser lower portion extending upwardly from the base member upper portion, the riser section having sidewalls with a generally corrugated shaped cross section in an axial direction. The hollow base member has a bottom and sidewalls, each of the bottom and sidewalls having an outer surface.

Abstract: A breather bag for an atmospheric storage tank vent seal includes a bag made with an impermeable and flexible membrane, to be used in storage and/or transportation of liquid product in atmospheric tank, by working as a breather to air vent either in a closed type or an open type tank. Because the stored liquid product in the atmospheric storage tank is kept physically separated from atmospheric air by using the breather bag, the following advantages are obtained. Evaporative losses of liquid products stored in atmospheric tanks are averted. Thus, environmental pollution by product gases that would be expelled out of the tanks is avoided. The entry of flames due to fire in atmospheric storage tanks that contain flammable or combustible liquids is avoided, so that the chances of an accident are reduced. Hydrocontamination of stored liquid product by water present in atmospheric air in atmospheric storage tanks is also avoided.

Abstract: Glass fiber reinforced plastic container for liquefied petroleum gas or compressed air. The container is made of two halves, the open ends of which are conically chamfered and joined to each other by an adhesive. In each half the reinforcement is made with inner, intermediate and outer layers, which comprise longitudinally as well as transversely and diagonally oriented bundles of reinforcing strands.

Abstract: A tank for storing liquid products, particularly a large capacity tank 1, comprises a bottom 5, whose center 6, is at a level below the level of the edge of the bottom. Drainage channels 7, consisting of a ramp 8, as floor with lateral plates 10, as sides, bring the undesirable materials to the edge of the tank where they can be drained out of the tank through drainage tubes.

Abstract: An improved aboveground system for storing a combustible fluid such as gasoline includes a storage tank that is constructed and arranged to store a combustible fluid such as gasoline and an outer tank to provide secondary containment. An interstitial space is defined between the outer tank and the storage tank. A pipe for communicating with the storage tank extends through the wall of the storage tank, into the interstitial space and through the interstitial space for a distance so as to extend substantially parallel to at least one of the walls of the outer tank and the storage tank, and then through the wall of the outer tank, whereby fluid may be supplied to or withdrawn from the storage tank. Advantageously, access structure is provided for gaining access through the wall of the outer tank to the portion of the pipe that extends through the interstitial space for a distance so as to extend substantially parallel to at least one of the walls of the outer tank and the storage tank.

Abstract: A treatment tank for a water conditioning apparatus includes a tank head with a wall with an interior surface and a noncircular rim that defines a first through hole in the wall. A generally cylindrical flange defines a first aperture and has a first nipple portion with a periphery and a noncircular portion radially extending from the periphery of the nipple portion. The noncircular portion is configured to matingly engage the noncircular rim so that contact between the noncircular rim and the noncircular portion prevents rotation of the flange relative to the tank head. A first fastener is engageable on the first nipple portion to secure the flange on the tank head through contact between the fastener and the tank head.

Abstract: An above ground storage tank for holding combustible material and for supporting equipment thereon, such as an electric power generator, has an inner tank with a bottom wall, opposed side walls, opposed end walls and a top wall preferably formed as metallic skins, the inner tank top and bottom walls having stiffening members, which is enclosed and supported in an outer tank having a bottom wall, opposed side walls, opposed end walls, formed as metallic skins with stiffening members on the top wall aligned with stiffening members on the side walls. A barrier insulation is preferably provided between the inner and outer tanks and mounting members are provided on the outer tank top wall to support equipment on the above ground storage tank.

Abstract: An improved portable fueling facility for aircraft or ground vehicles includes, in the disclosed embodiments, at least one storage tank, an outer tank for providing secondary containment about the storage tank, a number of saddle members for supporting the outer tank on a flat horizontal surface, and a pump for dispensing fuel. In one embodiment, a system is provided for suppressing combustion that might otherwise occur within the storage tank. To minimize heat transfer from outside the facility into the storage tank, fire-retardant insulation material may be positioned between the storage tank and the outer tank. The system also includes an environmentally controlled compartment for housing an electronic control system.

Abstract: A plastic vessel for a pressurized fluid, having an upper end wall and a lower end wall and an intermediate part with an outer wall and internal partition walls. The internal partition walls are placed in such a way in respect of each other and the outer wall that at least two longitudinal compartments for pressurized fluid are formed, which compartments are communicating with each other and run between the end walls. The vessel is non-circular. The outer wall between each pair of partition walls has a curve, with a radius adapted in such a manner that the tensions arising in the outer wall when the vessel is filled with a pressurized fluid will mainly be transformed solely to tensile stress in the partition walls which are joined to the outer wall. The partition walls are joined to the outer wall in the border lines where two such curves meet.

Abstract: A composite tank for a rinse system comprises a plate, a plurality of general planar fiberglass reinforced plastic walls, and a generally planar bottom wall. The plurality of general planar fiberglass reinforced plastic walls are attached to the plate and extend generally upwardly therefrom. The walls cooperate with the plate to define an interior region of the tank. The generally planar bottom wall is positioned to lie above the plate and is received in the interior region of the tank. The bottom wall is made from fiberglass reinforced plastic and is attached to the reinforced plastic walls to provide a sealed interior region of the tank between the walls and the bottom wall and above the plate.

Abstract: An above-ground flammable fluid containment apparatus and method are provided. The apparatus preferably has a primary fluid container for positioning flammable fluid therein and a secondary container having a bottom and a plurality of walls connected to and extending upwardly from the bottom so as to define an inner chamber. The plurality of walls include front and rear walls and a plurality of side walls connected to and extending between the front and rear walls. The secondary container has at least portions of the primary fluid container positioned within the inner chamber so that outer surfaces of the primary fluid container and inner surfaces of the secondary container define an interstitial space. A a weather shielding cover overlies and connects to upper end portions of the primary fluid container and the secondary container for enclosing the primary fluid container and for shielding the primary fluid container from exposure to various environmental conditions.

Abstract: An underground storage tank for use for wastewater storage or as a temporary holding tank for wastewater or runoff from drainage systems. The present holding tank includes a generally cylindrical sidewall having a plurality of integrally molded longitudinal and annular reinforcing ribs spaced circumferentially about the sidewall. The ribs greatly strengthen the sidewall against the crushing forces of hydrostatic pressure, and thus the present tank can be constructed from polyethylene. The bottom of the tank terminates in a tapered portion having a plurality of integrally molded reinforced support posts, each of which terminates in a ground support pad. A raised anti-flotation annular collar separates the tapered portion from the main body of the tank and prevents the tank from being lifted by hydrostatic pressure.

Abstract: An underground storage tank having a shape approximating a traditional bread loaf. A dome-shaped top extends vertically downward in integral common lateral sides, which terminate in an integral flat bottom.

Abstract: A storing tank, in which the storage space can be multiplied to a suitable extent, and the area occupied by it can be reduced. It has a lower tank member, an access gate, a pushing mechanism, an upper tank member and an outlet. Material put in the access gate falls onto the pushing mechanism to be pushed upwardly into the lower tank member. When the latter is full, the upper tank member is moved upwardly by the increasing material to increase the receiving space until the upper tank member is moved to the highest position. When the outlet is opened, the material can automatically fall down along a bevel guiding surface in the lower tank member and out of the outlet.

Abstract: A tank for compressed natural gas utilizes internal tension members. The tank has an upper half and a lower half, each half being formed with at least two cylindrical portions separated by a Y-shaped junction. The sections of each half have engagement members in the interiors. The engagement members include a head and a socket which slide longitudinally together to secure the upper and lower halves against tension due to the gas pressure.

Abstract: An improved storage system and a method of constructing the storage system adaptably satisfies structural requirements in different seismic zones. The storage system is efficiently constructed to restrain movement of a storage tank within a vault, even if the storage tank is positioned such that all sides of the tank are not physically accessible. Within the outer containment vault, a plurality of structural members and bottom restraints restrict movement of a storage tank relative to the vault. The structural member has two depending restraints, one on each side of the storage tank to wedge the storage tank in place. Additionally, the bottom restraints are structurally connected to the bottom of the vault and positioned in close proximity to the side of the tank to further restrain movement of the tank. Different sized storage systems may be constructed in compliance with seismic requirements by modifying the number and size of the structural members and bottom restraints within a particular storage system.

Abstract: A septic tank adapted for burial in soil includes a movable anchor that extends near the bottom of the tank to hold the tank in the soil.

Abstract: A material containment system is described that generally includes a containment tank, a skirt that is coupled to, supported by and extends outwardly from the tank, and a dike which defines a chamber for receiving the contents of the tank should such contents leak or otherwise be expelled from the tank. A tank stand optionally may be placed inside the chamber for receiving and supporting the tank. The skirt is spaced from the dike and extends beyond the periphery of the chamber so that substances contacting the skirt, such as rain, are guided away from the chamber. The system also may include at least one, and often plural, releasable tank fasteners that releasably couple the tank to the dike. The tank typically is a single-walled tank. Alternative embodiments include a double-walled tank, and a tank that has an upper double-walled portion and a lower single-walled portion.

Abstract: A tank, especially adopted for use aboard a ship, for transporting liquid natural gas. The tank comprises two substantially identical hemispherical sections which are connected to each other via a cylindrical section. The diameter of the cylindrical section corresponds to the diameter of the spherical sections. The length of the cylindrical section is less than 1/3 of its diameter. Further, the tank meets the standards of a Type B classification according to the regulations of the International Maritime Organization.

Abstract: A device for housing the active and passive junction assemblies of underground-located telecommunications installations, with a removable holding fixture for the assemblies placed inside the container, has the following characteristics:a) the container (6) has a hollow main body portion (6a) and a shoulder portion (6b) which extends conically towards one end,b) a hollow neck portion (6c) is adjacent to the conical portion (6b),c) the container (6) is closed by a cover (7), which simultaneously serves as a sidewalk cover,d) the container (6) rests on a pipe (2) cast into a foundation (1), which protrudes from the foundation (1), while the hollow neck portion (6c) extends into the pipe (2).

Abstract: A concrete liquid storage tank is supported by only three support points which rest upon a slab in permanent installation, which prevents twist forces being applied to the concrete shell of the tank in the event of vertical differential movement of portions of the slab under the support points, which prevents cracking of the concrete shell and leakage of contents to the environment.

Abstract: A secondary containment device is provided for protectively containing leaks and spills of a possibly hazardous or otherwise harmful chemical substance contained in a primary container such as a standard thirty or fifty-five gallon chemical drum. The device includes a tubular member with an open bottom equipped with a annular ring or foot of a resilient tacky material that forms a seal with the floor or other surface on which the drum is situated. A chemically resistant plastic material is preferred for the tubular member, which is preferably cylindrical. The foot is preferably triangular and presents a surface that is at least partially upwardly facing on the inside thereof so that the pressure of leaked chemical in the space between the drum and the sidewall of the device contributes sealing force to the foot. Where the floor is not sufficiently smooth to form a seal, a disc or sheet of a preferably plastic material is provided under the drum.

Abstract: A storage container (2) having secondary containment venting by form of construction includes an primary container (4) defining a primary containment region (24), a secondary container (6) and an interstice (8) therebetween. A portion of the top (16) of the secondary container is weakened so that in the event of an overpressure within the interstice, the weakened region fails allowing the overpressure to be vented to atmosphere. Two bands (34, 36) of fluid-accepting and -conducting material are wrapped at an angle to one another around the primary container within the interstice. The bands of material help to ensure that any overpressure within the interstice is substantially equalized throughout the interstice so that if the secondary container does fail, it fails at the weakened region.

Abstract: A remote spill containment apparatus that includes a horizontally oriented cylindrical housing, preferably formed of a single piece of rolled sheet steel closed front and back by welded spun plates. The upper, forward cylinder quadrant is cut away to form the access opening which is closed by an L-shaped lid hinged to rotate for storage beneath the housing to permit safe access to the housing interior. A single, infinitely adjustable post supports the rear of the housing for free access to the spill drain valve assembly located at the cylinder bottom. The round parts prevent snow and rain accumulation above the access opening and reduce manufacturing costs, weight and space of the unit. Spill liquid within the housing flows toward the bottom centerline lowest zone for selective removal through the spill valve assembly.

Abstract: The invention provides cryogenic structures, e.g. vessels or tanks joined by longerons, which are made of durable plastic composite materials rather than of metal, which vessels can contain cryogenic materials including fuel, without need of a liner or other weighty layers of the prior art. The structures are made of, e.g. a fiber network impregnated with a matrix of thermoset plastics, thermoplastics or a combination thereof. Thus the invention includes a cryogenic vessel of, e.g. 3 tank lobes, made of a composite of plastic reinforced with fibers, which lobes are joined together and supported by woven, cruciform shaped longerons which are also impregnated with plastic, to define a composite support member.

Abstract: A compressed natural gas refueling station tank comprises an elongated tubular body having a diameter of about 8 to 10 inches and a length of 50 feet or more. The tank is bent into a serpentine shape to produce a compact configuration which can be stacked with other like tanks and connected to a compressor through a manifold.

Abstract: A corrosion-resistant storage tank for collecting runoff liquids is provided. The storage tank is formed from a plastic and has a bottom; a vertical side wall having at least one aperture, and a removable cap having at least one cap aperture therein and at least one flange positioned in the cap aperture.

Abstract: A liquid container for the above-ground storage of flammable fuels is shown having an inner tank with a bottom surface, side surfaces, and a top surface placed within an outer shell having a bottom surface, side surfaces and an open top. The bottom surfaces of the inner tank and outer shell are spaced apart from each other, as by first bottom spacers which connect the two bottom surfaces. The side walls of the inner tank and outer shell are also spaced apart from each other, as by second side spacers which connect the tank and shell. The spacers for connecting the tank and shell prevent the inner tank from floating within the outer shell when an insulating material, such as concrete, is added therebetween.

Abstract: A double wall ribbed storage tank system is provided with the capability of independent monitoring of support rib areas and secondary containment areas of the tank system. The storage tank system comprises (a) an inner storage tank for primary containment of stored liquid with a set of support ribs for strengthening purposes, (b) an outer wall over the inner tank for secondary containment of the stored liquid, (c) rib communication means connecting together the support rib areas, (d) wall communication means connecting together secondary containment areas of the inner storage tank and outer wall, and (e) a monitoring station operably associated with the rib and wall communication means. Any structural damage to a support rib, inner storage tank wall or outer wall is detectable and generally located by the monitoring station.

Abstract: Glass-fibre reinforced plastic tank, for example for liquid petroleum gas under high pressure, compressed air for air brakes or for storage of acetylene. The tank is composed of two halves, the open ends of which are conically bevelled to form a male end and a female end, which are joined to each other by an adhesive. The reinforcement in the outer and inner layers of the halves contains essentially longitudinal glass-fibre strands and the intermediate layer contains essentially longitudinal glass-fibre strands and the intermediate layer contains essentially transverse glass-fibre strands. In the half with the male end, the longitudinal glass-fibre strands in the inner layer are densely located adjacent to each other, while the longitudinal glass-fibre strands in the outer layer lie in separate groups of densely arranged glass-fibre strands with the predetermined spacing between the groups to form channel-shaped spaces. In the half with the female end, the order is reverse.

Abstract: A composite double-wall underground tank comprises an internal rotatable metal mandrel tank frame structure surmounted by two individual concentric corrugated cylindrical nonmetallic pressure vessels having hemispherical ends. The metal tank frame structure provides the buckling resistance and compression strength to resist soil loads when the tank is buried. The pressure vessels are made of identical materials and include an internal primary container enclosed by an external secondary container of equal tensile strength and corrosion-resistance. The composite double-wall underground tank is a substantial improvement over conventional steel and fiberglass tanks, and provides a more reliable method of protecting the environment by preventing the release of contaminating hazardous liquids stored in the tank. Each of the two pressure vessels is made from a multiple ply composite laminate having a unique arrangement of fabrics containing filament reinforcements impregnated with a thermosetting polymeric matrix.

Abstract: A fuel fill pipe shelf for a generator set fuel tank is mounted in the upper end of a tower of the fuel tank. The fuel pipe shelf comprises an insert which is welded into an opening in the upper end of the fuel tank. The insertcupies a volume which otherwise would be part of the interior of the fuel tank. The fuel fill, vent and fuel gage are all supported on the fuel shelf. As a result, the fuel fill, fuel gage and vent are all within a protected recess in the fuel tank.

Abstract: A tank head insulation cover comprising a plurality of generally wedge shaped panels with flanges, the panels being assembled in an overlapping manner onto the tank head so the flanges are in close relation to the perimeter of the tank. A center cap is provided to cover the area left uncovered by the panels.

Abstract: An above ground storage container assembly comprises a steel tank for volatile liquid housed within a concrete vault. The walls of the vault are spaced from the tank to provide an air envelop around the tank. The air envelop is vented to prevent the tank from rusting or corroding. Lifting bars are anchored in the vault so that the entire assembly may be raised. A spill trap surrounds the fill opening from the tank and also surrounds a drain hole with removable plug.

Abstract: Inner and outer welded steel protective tanks are separated by a space containing a granular insulating material such as perlite preventing excessive heating of fuel in a storage space in the inner tank, even when there is a fire at the site. The inner tank may be subdivided into portions by a partition defining a storage space and an overfill containment space receiving overflow from the storage space portion, with a sensor detecting overflow. The overflow containment space is also arranged to collect separated fuel when the tank system is used with a vapor recovery system. The granular insulating material acts as an explosion suppressant by dissipating heat and fuel vapors which may be present in the insulation space as a result of leakage from the inner tank. A triple walled tank of increased reliability against spills and penetration resistance is provided by a two closely spaced inner tanks within the insulation. Insulated tank saddles provide fire protection for the tank support.

Abstract: An improved portable fueling facility for aircraft or ground vehicles includes, in the disclosed embodiments, at least one storage tank, an outer tank for providing secondary containment about the storage tank, a number of saddle members for supporting the outer tank on a flat horizontal surface, and a pump for dispensing fuel. In one embodiment, a system is provided for suppressing combustion that might otherwise occur within the storage tank. To minimize heat transfer from outside the facility into the storage tank, fire-retardant insulation material is positioned between the storage tank and the outer tank. In addition, a heat sink may be positioned between the two tanks to intercept heat that would otherwise flow to the storage tank.

Abstract: A structure or cooling a large cylindrical storage tank has the shape of an inverted funnel and is intended to be disposed over the tank receiving the upper portion therein and internal struts are provided to separate the funnel wall from the tank wall, The separation allows the entry of air into the funnel structure so that as the structure is heated by the sun air currents will rise through the funnel exiting the chimney which will result in an inflow of air into the funnel around the walls of the tank.

Abstract: A bladder mounting for a storage tank has a plurality of threaded studs, spaced circumferentially along an upper portion of an inner surface of the tank side wall. At least one layer of geotextile padding, is adhered to the inner surface of the wall below the studs. A liner with a reinforced hem has circumferentially spaced apertures which receive the studs and suspend the liner within the tank. A circumferential band of adhesive material along the studs and apertures and between the wall and the liner seals the liner to the inner surface of the tank along a continuous path. A circumferential strip of battan has spaced apertures to receive the studs for clamping the liner against the inner surface of the wall with the band of adhesive therebetween. Nuts and washers engage with the threaded studs and draw the battan toward the wall to secure the seal along the continuous path.

Abstract: An above-ground secondary containment unit for storage tanks is comprised of a rigid base and upwardly extending side and end walls. Side cover shields are mounted to the top of the side walls by way of hinges and are intended to contact a side surface of the storage tank thus minimizing or preventing the entry of precipitation or debris into the unit while the tank is in place. End cover shields are mounted to the top of the end walls using a nut and bolt arrangement and slots in the shield allowing for lateral adjustment of the shields with respect to an end surface of tanks of varying sizes and configurations. These shields similarly minimize or prevent the entry of precipitation and debris into the unit. The walls of the unit are tapered so that one unit may be nested within another similarly shaped unit for convenient storage and to permit shipment of multiple units at the same time.

Abstract: A water seal device for closing a tank containing a corrosive product, such as acid, closed by a cover having a side lip which is able to engage, on closing, in a U-shaped channel provided along the upper edge of the side wall. The channel is made up of monolithic shaped elements, each made from a natural rock of eruptive origin of the lava type, and arranged in sequence on the upper edge of the side wall. The invention applies particularly to installations for chemically pickling sheet metal.

Abstract: A system for the storage and dispensing of liquid product from an underground installation comprises a storage tank which bears on its top a containment chamber enclosing all fittings for apparatus which gasoline or other stored product will pass through under pressure. Attached to at least one fitting each are a fill arrangement for introducing liquid to the storage tank, and a pump for pumping fluid therefrom, both of which are entirely enclosed in secondary containment, the storage tank itself and piping also being enclosed in secondary containment, such that the system is pressure tight, and recovers all leaked fluid in a state in which the fluid can be reused.

Abstract: A substantially gas-tight tank cover is designed such that the structural beams of the cover serve also as a gas withdrawal system for removing odorous or deleterious gases from above the surface of a liquid in the tank, such as in the case of a sewage treatment plant. The structural beams are tubular in cross-sectional shape, and have openings at selected locations in communication with the interior of the tank above the liquid. The system efficiently uses the structure of the tank cover as part of the odorous gas withdrawal system.

Abstract: A container for holding fluent material comprises a bag of flexible sheet material defining a volume for containing a load of the material. The bag has a side wall with an inside face and an outside face, and a bottom margin defining an open lower end of the bag. The container further comprises a substantially rigid, non-circular base for supporting the bag. Channels are formed in the base and extend at least partially around the base. The bag is fitted on the base with the bottom margin of the bag extending down on the outside of the base and with a portion of the bottom margin received in the channels of the base. Locking strips are positioned in the channels to overlie the portion of the bottom margin of the bag received therein. The container further comprises a clamping mechanism securable to the base for applying pressure to the locking strips to press the portion of the bottom margin of the bag against one or more surfaces of the channels thereby to sealingly secure the bag to the base.

Abstract: An underground storage system for hazardous liquids having an inner fluid storage tank surrounded by a larger outer containment vault with sufficient space between to allow for visual inspection of the tank. The inner tank has a rectangular parallelepiped shape and is positioned within an outer rectangular parallelepiped vault in a manner leaving a larger clearance space between two adjacent tank sides and facing vault walls than between the opposite adjacent two sides and walls. Additionally, a vertical clearance exists between the tank and vault. The vault is reinforced concrete precast in sections for ease of transport and assembly on-site. The vault has a bottom pan-shaped unit with one or more square tubular collar units on top and terminates in an upper cover. The cover includes one or more man-way apertures enabling a technician to enter the vault and inspect the tank for leaks. The increased use of excavated space for fluid storage reduces costs associated with transport and installation.

Abstract: A double wall storage tank system has its walls bonded together in a defined intermittent manner. The storage tank system comprises a tank having a cylindrical-shaped main body and end walls at each end thereof. A continuous wall covers the tank and is bonded thereto in a defined, e.g. helical pattern. Unbonded wall portions between the bonded wall portions form flow channels extending the full length of the cylindrical-shaped main body of the tank such that leakage through any part of the tank or continuous wall is detectable.

Abstract: Apparatus for holding materials including a container having a container wall, a non-circular container opening extending through the container wall, a non-circular container flange connected to the exterior of the container wall and surrounding the container opening. A non-metallic, non-circular access hatch connectable to the container flange by bolting and having a plurality of apertures extending therethrough is provided. The non-metallic, non-circular access hatch preferably includes a primary opening having a removable cover and a variety of associated components being accommodated by respective apertures such as a recirculation line, a pressure relief valve, a vacuum relief valve, and a fluid level indicator. Preferably the hatch apparatus and the primary opening cover are made of an ultra high molecular weight polyethylene material.