Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16L—PIPES; JOINTS OR FITTINGS FOR PIPES; SUPPORTS FOR PIPES, CABLES OR PROTECTIVE TUBING; MEANS FOR THERMAL INSULATION IN GENERAL
  • F16L11/00—Hoses, i.e. flexible pipes
  • F16L11/04—Hoses, i.e. flexible pipes made of rubber or flexible plastics
  • F16L11/12—Hoses, i.e. flexible pipes made of rubber or flexible plastics with arrangements for particular purposes, e.g. specially profiled, with protecting layer, heated, electrically conducting
  • F16L11/121—Hoses, i.e. flexible pipes made of rubber or flexible plastics with arrangements for particular purposes, e.g. specially profiled, with protecting layer, heated, electrically conducting specially profiled cross sections
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16L—PIPES; JOINTS OR FITTINGS FOR PIPES; SUPPORTS FOR PIPES, CABLES OR PROTECTIVE TUBING; MEANS FOR THERMAL INSULATION IN GENERAL
  • F16L11/00—Hoses, i.e. flexible pipes
  • F16L11/22—Multi-channel hoses
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16L—PIPES; JOINTS OR FITTINGS FOR PIPES; SUPPORTS FOR PIPES, CABLES OR PROTECTIVE TUBING; MEANS FOR THERMAL INSULATION IN GENERAL
  • F16L39/00—Joints or fittings for double-walled or multi-channel pipes or pipe assemblies
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16L—PIPES; JOINTS OR FITTINGS FOR PIPES; SUPPORTS FOR PIPES, CABLES OR PROTECTIVE TUBING; MEANS FOR THERMAL INSULATION IN GENERAL
  • F16L9/00—Rigid pipes
  • F16L9/18—Double-walled pipes; Multi-channel pipes or pipe assemblies

Definitions

• the present invention relates to secondary containment systems and especially, although not exclusively to a piping construction and a method for providing secondary containment systems for hydrocarbon storage and delivery systems.
• a secondary containment system is one which functions to collect and contain the fluids leaking out of another and primary containment system.
• a primary containment system may store and delivery gasoline at a filling station.
• a secondary containment system would collect and contain the same gasoline if a primary delivery pipe should rupture or otherwise spill the gasoline.
• Secondary containment systems have been developed to overcome the environmental problems that have been encountered with respect to leakage of hazardous fluids from tanks and pipe lines. As indicated, this has been a particular problem with respect to underground installations in which undetected leakage of hazardous fluids into the surrounding terrain over long periods of time has produced harmful conditions and extensive pollution which are difficult and expensive to clean.
• the outer secondary containment rigid pipe is installed simultaneously with the product piping.
• the outer secondary containment pipe by necessity has a larger diameter than the supply pipe to enable secondary containment pipe to slide over the smaller pipe.
• the secondary containment pipe fittings are of a clam shell design adapted to fit over the supply pipe fitting and connect to the secondary containment pipe.
• the clam shell fitting is sealed to itself and the secondary container pipe by a variety of sealing techniques. Depending on the type of secondary containment system used, these sealing techniques could include metal or plastic fasteners used with a combination of adhesives, sealants and the like.
• Such secondary systems are generally expensive to install because of the cost of the components which are used and the time required to assemble both the product and the secondary containment piping systems.
• This type of containment system differs from the first described systems in that it is not an entirely rigid straight pipe but rather a combination of rigid straight pipe with a larger diameter convoluted plastic pipe over it which produces a telescoping effect.
• the convoluted section of telescopic containment pipe serves as a fitting of containment of the product, 90° and 45° fittings as well as unions, flexible connectors, swing joints, should they be so attached.
• the convoluted pipe is designed to be flexible and sized to be shifted around any angles in the production piping system.
• Another type of secondary containment piping system which utilizes spaced access chambers interconnected by a secondary containment pipe to provide a sealed housing for a flexible fluid supply pipe, the ends of which are disposed within the access chambers and have a connector element at each end forming a section adapted to be interconnected to other fluid conduits.
• the diameter and bending radius of the fluid supply pipe and the size of the access chamber are such as to permit the fluid pipe, after uncoupling, to readily be removed from the secondary containment pipe through one of the access chambers. Should a leak occur in the piping, the secondary containment system allows the piping to be removed and replaced.
• an object of the invention is to provide a new and improved secondary containment system which will draw all spilled fluids that may leak from a primary supply pipe to a preselected collecting point which may be monitored.
• Another object of the present invention is to provide a practical secondary containment system which may be manufactured in a factory, shipped and installed at a reasonably low cost in a fully usable manner and yet one which meets all requirements of the environment within which they must be used.
• Fig. 1 is a schematic layout of an exemplary gasoline storage and delivery system
• Fig. 2 is an enlarged side view of a portion of the fuel dispensing system of Fig. 1 as seen generally along line 2-2 thereof;
• Fig. 3 is an enlarged view of a portion of the system illustrated in Fig. 2;
• Fig. 4 is an enlarged perspective view of the inner and outer pipes utilized in the secondary containment piping system of the present invention with layers of the inner pipe removed for illustrative purposes;
• Fig. 4A is a fragmentary perspective view of the outer secondary containment pipe illustrated in Fig. 4;
• Fig. 5 is a cross sectional view taken generally along line 5-5 prior to the backfilling of the trench within which the pipes are located;
• Fig. 6 is a view similar to Fig. 5 illustrating, in a slightly exaggerated manner, the secondary containment piping system after backfilling. DESCRIPTION OF THE PREFERRED EMBODIMENTS
• FIG. 1 wherein there is illustrated an underground fuel storage and dispensing system generally indicated at 10 comprising fuel tanks 12 from which a plurality of underground fuel supply pipes
• the system includes one or more access chambers 20 which are also disposed below the surface dispensing station 16.
• the access chambers 20 and the fuel tanks 12 are interconnected by containment pipe segments 22 while the access chambers are connected via pipe segments 24 to a conventional drip pan 26 beneath the dispenser 16 and is connected thereto through suitable elbow connectors 28.
• the access chamber 20 and the pan 26 are interconnected in a fluid sealing manner through their side walls just above the bases thereof by means of the secondary containment pipe 24.
• the side wall 30 of the access chamber 20 has an opening 32 through which the end of the pipe 24 extends.
• a conventional seal 34 surrounds the outer surface of the containment pipe 24 and provides a fluid tight seal for the interior of the access chamber 20.
• the secondary containment piping system comprises a flexible inner supply pipe 40 which is completely encased within a flexible outer containment pipe 42.
• the outer containment pipe 42 extends into the access chamber 20 a sufficient distance so that it clears the interior of the wall 30 of the access chamber 20. During fabrication this will permit the insertion on the terminated end 39 of pipe 42 of a suitable air pressure device to permit testing as will be explained hereinafter.
• the inner pipe 40 extends past the terminated end 39 of the outer pipe 42 a sufficient distance to permit it to be coupled by suitable conventional couplings 44 to another inner pipe 40 which, in turn extends outwardly from the access chamber 20 through an outer containment pipe 42.
• the pipe 40 exist therethrough and continues through a containment pipe 42 on to the next island.
• the access chamber 22 has a removable cover 70 to permit easy access thereto for removal of any fuel that might be captured by the containment pipe 40.
• a fluid sensor 72 is disposed in the bottom of the access chamber 22 and is electrically connected to an appropriate indicator or alarm 74. When there is an accumulation of fluid, such as due to leakage from the primary pipe 40, the fluid will actuate the alarm.
• the inner pipe 40 is made from a fuel impervious material and is comprises of three layers of material which are extruded together and comprise an interior layer 50, which is fabricated from a nylon 12 material; a intermediate layer 52 consisting of a nylon 6 yarn reinforcement wrap; and an exterior outer material 54 which is preferably fabricated from a polyethylene material.
• the inner layer 5 50 is .080" thick and the outer layer is preferably 060" thick.
• the pipe 40 has an inside diameter of 1.68" and an outside diameter of 1.960", a maximum operating pressure of 150 psi and a minimum burst pressure of 750 psi.
• the material is 0 flexible and has a bend radius of 12" to 24".
• the inner pipe 40 is completely encased in the outer containment pipe 42 which, as can best be seen in Figs. 4, 4A and 5, comprises integrally extruded member a having a wall 60, the interior of which is provided with 5 a plurality of angularly spaced, radially inwardly extending ribs or projections 64 that define therein between U-shaped cross sections 60.
• the projection extends along the full length of the interior of the wall 60 (Fig. 4A) .
• the outer pipe 42 is sized to permit the 0 inner pipe 40 to be inserted therein with little or no resistance and is, preferably, assembled in the combined arrangement at the factory, ready for positioning in the pipe trenches when delivered onsite.
• the outer pipe 42 is very flexible and can bend as needed to accommodate 5 the bending of the primary inner pipe 40.
• the outer pipe 42 is made from a fuel impervious material such as a nylon or polyethylene, clear acrylonitrile or clear polyurethane material.
• the weight of the earth on the flexible outer pipe 42 deforms the pipe 42 in the manner similar to that illustrated in Fig. 6 of the drawings, until the outer ends of the projections 64 abut the outer wall of the inner pipe 40.
• the abutment of the projections 64 with the wall 40 provides a two-fold purpose. First, it snugly and lockingly engages the pipe 40 and prevents relative movement between the inner and outer pipes providing for a more secure system, and secondly, the space between U-shaped cross sectional areas and the space between the inner and outer walls always insures a flow path for any fuel that may leak into the annular space between the inner and outer pipes.
• the view illustrated in Fig. 6 is exemplatory of the condition that may exist.
• the outer tube 42 may be deformed in a variety of different shapes. Suffice it to say, that a continuous flow path will exist in the event there is a leakage from the primary inner pipe 40. While it is preferred that the primary pipe 40 and secondary containment pipe 42 be assembled at a factory location there may be situations in which the pipes are assembled on site before burial. The pipe 40 may be removed and either pipe may be replaced if a leak is found during testing. Once buried, the weight of the fill collapses appropriate portions of the outer containment pipe 42 around the primary pipe 40 and the primary pipe 40 may no longer be removed after burial.

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• Engineering & Computer Science (AREA)
• General Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Rigid Pipes And Flexible Pipes (AREA)

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Citations (3)

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• 1993
  • 1993-03-25 CA CA002109730A patent/CA2109730C/fr not_active Expired - Fee Related
  • 1993-03-25 WO PCT/US1993/002977 patent/WO1993020372A1/fr not_active Ceased
  • 1993-03-25 EP EP19930909213 patent/EP0592639A4/en not_active Withdrawn

Patent Citations (4)

Non-Patent Citations (1)

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