Abstract: An incandescent bulb for use in a submerged swimming pool light fixture is disclosed, which includes a filament, at least one spring-biased filament support, and a grounding device. The filament support includes an exposed current-conducting portion and is moveable in response to the spring bias. The current-conducting portion of the filament support is arranged to allow it to come into electrical contact with the grounding device when the filament support moves in response to the bias of the spring. The filament is disposed to prevent movement of the filament support when the filament is intact and the lamp is in normal operating condition.

Abstract: A filament-wound pressure vessel having a pressure vessel liner and a continuous filament polar wound over the surface of the liner in an isotensoid pattern. The liner has a geodesic dome surface extending between a diameter of the liner and a polar opening. The dome surface is defined by oppositely curving surfaces of revolution of a meridia joined by an inflection point. The first surface of revolution curves from the liner diameter to a first point just unto but not at said inflection point. The second surface of revolution curves from the polar opening to a second point just unto but not at said inflection point in a direction opposite the curvature of the first surface of revolution. The first and second surfaces are joined, and the inflection point is traversed by a straight line third surface of revolution closely approximating geodesic curvature through the inflection point.

Abstract: A hydropneumatic filament-wound pressure vessel is disclosed. The vessel has first and second cup-shaped tank liners having circular open mouths which are provided with a seal and diaphragm assembly. The seal assembly includes a pocket formed by an inner wall and shelf associated with the first liner and a ledge associated with the second liner. The shelf, ledge and cylindrical wall cooperate with an inner surface of the second liner to provide an O-ring pocket. An O-ring is provided in the pocket and the O-ring defines the periphery of a flexible diaphragm which divides the interior of the liners into separate pressure chambers. A continuous filament is wound over the surface of the liners in an isotensoid pattern. Each liner has a geodesic dome surface extending between a diameter of the liner and a polar opening. The dome surface is defined by oppositely curving surfaces of revolution of a meridia joined by an inflection point.

Abstract: A diffuser is attached to a flexible inner cell inside an outer vessel. The outer vessel contains a first fluid and the inner cell contains a second fluid. The diffuser has a flange which is sandwiched between a flanged port and a flanged neck of the outer vessel. The diffuser is contained substantially within the neck of the outer vessel. A generally circular surface of the diffuser deflects fluid entering the outer vessel through the port. A side wall of the diffuser is provide with apertures to permit passage of the fluid therethrough.

Abstract: A hydropneumatic filament-wound pressure vessel is disclosed. The vessel includes a split tank closure and diaphragm assembly comprising a pari of cup-shaped plastic tank liners having cylindrical sidewall portions terminating in circular open mouth portions. A cylindrical ring is interposed between the open mouths of the liners and is sealed to the liners by a fusion welding operation. A cup-shaped elastomeric diaphragm is sealed to the cylindrical ring and separates the interior of the vessel into a pair of pressure chambers. The outer surface of the tank is helically wound with a resin-impregnated continuous filament.

Abstract: Method and apparatus for rotationally casting a plastic tank liner having a molded-in access fitting and for ensuring a uniform thickness of plastic in the wall of the liner and on the fitting. A hollow mold having a mold cavity surface conforming to the surface of the liner is provided. An access fitting is removeably mounted on the mold so that the interior surface of the fitting may be coated with the molding plastic and so that the molded liner and the filling may be removed from the mold as a unit. The mold is rotated about orthogonal axes while the mold is heated to a resin liquifying temperature. Additional heat is supplied to the fitting at a rate proportional to the mass of the fitting so that the temperature of the inside surface of the fitting is increased at a rate substantially corresponding to the inside surface temperature of the mold.

Abstract: A pressure switch adaptor designed to replace existing pressure switch adapters or connections and pressurizing air valves conventionally associated with water storage and distribution tanks. The adaptor is designed to be used as original equipment on new water tanks or to retrofit existing tanks, replacing the pressurizing air valve conventionally provided by the latter. Whether used on a new tank or retrofitting a used tank, the pressure switch adaptor fits into the port conventionally reserved for the pressurizing air valve. The adaptor provides a pressurizing air valve to allow initial pressurization of the air filled diaphragm and a pressure switch connection for fluid communication between an internal tank diaphragm and the pressure switch, which controls actuation of the tank's water-supplying pump. By placing the pressure switch adaptor on the air side of the system, problems associated with corrosion and corruption of the switch due to prolonged contact with water are eliminated.

Abstract: The present invention is directed towards an air relief valve for a pressure vessel which automatically releases air from the system during filling with liquid, and which automatically seals when the liquid in the system reaches a predetermined level to prevent the liquid from leaving the system. The air relief valve of the present invention includes a valve body which provides communication between the pressure vessel and a series of output ports. These output ports are provide with a pressure indicator, a manual pressure release valve, and an automatic air relief valve. The manual pressure release valve is operable by the user to introduce air into the system, which is necessary during draining. The automatic air relief valve is generally a one-way valve, allowing air to exit but not enter the system.

Abstract: A pool drain assembly for a swimming pool having a vinyl liner is disclosed. The assembly includes a drainage receptacle which has an upper edge portion substantially at a level defining the bottom of the swimming pool. The receptacle has a conically shaped seating surface, and the vinyl liner covers the surface. A clamping ring is seated on the seating surface and surrounds a strainer plate which also rests on a lower edge of the seating surface. The upper surfaces of the pool liner, the clamping ring, and the strainer plate are all substantially co-planer.

Abstract: A pressure relief seal for pressure tanks having separable tank sections is disclosed. The seal is formed by an O-ring within an O-ring cavity, in turn formed by each tank section. Overpressurization or improper assembly of the tank sections causes the O-ring to be displaced from its sealing position to permit fluid in the tank to flow past the O-ring and through pressure relief channels at the seal.

Abstract: A polyethylene shipping drum especially suited for shipping hazardous materials is disclosed. The drum comprises a molded container and closure which are threadably connected to each other to form a seal therebetween. A thread lock is provided for the threaded connection between the container and closure. The container has a plurality of indentations in the side wall thereof to provide ledges for stacking the containers one inside the other in a stable, nested relationship. An annular rim is provided on the closure with an inclined annular surface for retaining the sealing gasket in a groove without adhesives.

Abstract: A pressure relief seal for pressure tanks having separable tank sections is disclosed. The seal is formed by an O-ring within an O-ring cavity, in turn formed by each tank section. Overpressurization or improper assembly of the tank sections causes the O-ring to be displaced from its sealing position to permit fluid in the tank to flow past the O-ring and through pressure relief channels at the seal.

Abstract: A regenerating control system for liquid conditioners includes ball valves positioned and sized so that they do not cause any flow restriction during the normal operation of the conditioner. The valves are operated by low voltage D.C. motors which require power only while moving the valves from one position to another position. An electronics control system and timer control the operation of the valves and require very small amounts of power. Consequently, a battery backup system can operate for extended periods of time when a commercial power outage occurs. A two-piece housing assembly provides improved seals for sealing between the two housing halves and between the housing assembly and the valve.

Abstract: A method and apparatus for attaching an insert in an opening in a molded thermoplastic body. The insert includes a thermoplastic mounting portion which is fused with the thermoplastic material of the body. The insert is maintained in a spaed position from the opening during the heating portion of the molding cycle and positioned within the opening while the thermoplastic material is still sufficiently hot to fuse with the thermoplastic mounting portion of the insert.

Abstract: A die changing mechanism for use with a vertical-axis extrusion apparatus that includes a die housing and an extrusion die section, such as an inner section that is secured to the housing by a threaded connection. The apparatus includes a transportable support assembly and a breaker assembly supported by the support assembly and adapted to be positioned in an initial position in rotationally interlocking engagement with the inner die section. The breaker assembly is connected to the support assembly by threaded means, and is adapted for rotational movement relative to the support assembly about a vertical axis corresponding to the screw axis. The pitch of the threads of the threaded means is the same as the pitch of the threads by which the die section is connected to the die housing.

Abstract: A filter distributor is disclosed which includes a plurality of radially-extending conduits or laterals pivotally mounted at their inner ends on a hub and extending to outer ends substantially adjacent to the outer wall of the filtered tank. Each lateral is provided with an inner strainer and an outer strainer. The outer strainers are sized to service an adjacent zone along the outer portions of the tank and the inner strainers are sized to service adjacent inner zones. In the illustrated embodiment, the outer strainers have an open flow area twice as great as the inner strainers and service the outer two thirds of the tank. The strainers are positioned substantially at the centroid of the adjacent zones which they service. The sizing of the strainers and their location is arranged so that substantially uniform flow occurs through all of the filter medium during normal filtering operation and backflow operations.

Abstract: There is disclosed apparatus for rotationally casting a plastic liner for a pressure vessel having a metal access fitting molded therein. The apparatus includes a rotational casting arm having a mold supporting surface and adapted to be rotated about orthogonal axes. A hollow mold having a mold cavity surface conforming to the outside surface of the liner to be molded is removably attached to the mold supporting surface together with a metal access fitting. The metal access fitting has a longitudinal axis aligned with one of the orthogonal axes and has at least a first surface portion extending into the mold cavity. The first surface portion and the surface of the mold cavity are coated with plastic upon mold rotation to form the plastic liner.

Abstract: An accumulator tank for pressurizing and supplying liquid to a system comprises a pressure vessel having a wall defining a closed pressure chamber. The pressure vessel is provided with an internal flexible air cell which divides the pressure chamber into first and second variable volume compartments containing pressurized air and water, respectively. Perforated conduits are provided in the second compartment in fluid communication with a port, and extend between the wall of the pressure vessel and the flexible air cell. The perforated conduits provide fluid communication between the port and portions of the second compartment when the air cell seals against the wall to otherwise isolate those portions of the second compartment in fluid communication with the perforated conduits.