Abstract: A coupler (A) defines a bell (C) having a cylindrical wall (40) of substantially the same inner diameter as an outer diameter of peaks (22) of a length of corrugated tubing (B). The corrugated tubing includes a gasket (30) received in a valley (24) near one end thereof. The gasket includes a flange portion (32) which is compressed into the valley by the side wall (40) as the end of the tubing is slid into the coupler (A). The coupler includes an annular groove (44) which is in alignment with the gasket when the inner end of the tubing engages a stop (10). The flange is resiliently biased outward into groove (44) where an outward facing groove engaging surface (46) of the gasket engages an inward facing gasket engaging surface (48) of the groove. The gasket may include a stiffer higher durometer rubber portion (52) for biasing the flange more stiffly into the groove and to transfer axial load to the bell more stiffly.

Abstract: A corrugated plastic side wall (A) extends from a bottom area (14) to an apex area (12). A riser (B) extends from the apex area above the ground level. A ring of steel channel (10) is fastened around the apex area to prevent the apex area from becoming distorted when the soil in which the tank is buried becomes water-laden. A tank bottom wall (122) is domed inward to inhibit exterior hydraulic pressure from flexing the bottom inward and from urging the corrugated side walls adjacent the bottom to compress to a smaller diameter in an accordion-like fashion. Downward projecting can (124) and boxes (126) extend from the domed bottom surface to a flat plane to prevent the dome from flexing outward under the weight of sewage and other fluids in the interior of the tank. At least one annular projection (52) extends around an outlet opening (44) to enable a tank wall portion (54) adjacent the outlet opening and outlet tubing (48) to move relative to the remainder of the tank.

Abstract: A sleeve of plastic material from an extruder is molded by a blow molding apparatus into a tubular structure which includes two top walls longitudinally connected at base ends and apex ends. A splitting apparatus splits the longitudinally connected base ends apart to form two top walls. The top walls are oriented with their base ends upward. An extruder extrudes a flow of softened plastic which is divided by a manifold into four flows. Four applicators connected with the manifold apply beads of softened plastic along each top wall base end. A ribbed roller presses flexible strips against the plastic beads on each of the top walls. The flexible strips are fed from rolls of finite length mounted on a stand. The stand holds operating rolls and back up rolls. A splicing apparatus splices the trailing end of each operating roll with a leading end of the corresponding back up roll.

Abstract: The conduit includes a top wall (A) and a base (B). The top wall A has an apex area (10) which is connected with a first corrugated side wall (12) and a second corrugated side wall (32). The side walls having alternating peaks (22, 42) and valleys (24, 44). The peaks have apex ends (26, 46) which are disposed closely adjacent each other at the apex area to define a hinge region therebetween. Disposed along the apex area and on the side wall peaks are a plurality of outward projecting dimples (70, 72, 74) which are severable by a tangentially disposed knife blade to form a plurality of apertures (50, 52, 54). The base B is a flexible sheet of plastic mesh material.

Abstract: A plurality of internal couplers (A, B, C, D) are integrally connected end to end in a single tubing construction of indeterminant length. Between each coupler is an annular, frangible region (14, 24) of thin plastic. In the field, the individual couplers are readily broken manually from the tubing construction. Each coupler includes a plurality of cleats (40) which are partially surrounded by a region (50) of relatively thin plastic material. The couplers are manufactured by continuously blow molding a sleeve of softened plastic into the tubing construction of indeterminent length.

Abstract: A plurality of internal couplers (A, B, C. D) are integrally connected end to end in a single tubing construction of indeterminant length. Between each coupler is an annular, frangible region (14, 24) of thin plastic. In the field, the individual couplers are readily broken manually from the tubing construction. Each coupler includes a plurality of cleats (40) which are partially surrounded by a region (50) of relatively thin plastic material. The couplers are manufactured by continuously blow molding a sleeve of softened plastic into the tubing construction of indeterminent length.

Abstract: An end cap particularly adapted for capping an arch conduit is provided. The end cap is comprised of an arch body including opposed arcuate side walls integrally joined together at an apex area. Opposed arcuate end walls are integrally joined at the terminal ends of the side walls and the apex area. A plurality of protruding ribs are disposed circumferentially of the end cap and are interrupted at the apex area to provide a relatively smooth, non-ribbed area. The ribs taper towards the apex area and towards rounded base areas of the side walls.

Abstract: The coextrusion die assembly receives a first and a second plasticized material flow which it forms into a layered, cylindrically tubular flow. An inlet block (100) receives the first material flow axially and the second material flow radially. A manifold block (200) forms the first material flow into a cylindrical flow and divides the second material flow into eight equal flow portions. A spider structure (300) has a first plurality of apertures (302-308) which pass the first material flow and eight second apertures (330-344) which receive the eight second material flow portions from the manifold. Each of the eight second spider apertures has a relatively small upstream opening and fans peripherally outward into a continuous cylindrical downstream region. A non-linear restriction means (440-454) provides a greater restriction in longitudinal alignment with the center of each of the second apertures and a less restrictive region therebetween.

Abstract: A plow arrangement is disclosed for inserting continuous lengths of foldable conduit in the ground. A plow forms a cavity in the ground for receiving the conduit. Folded conduit is conveyed from a reel to an inlet end of a feeder or boot. As the conduit passes through the feeder, it is unfolded. The feeder discharges the unfolded conduit horizontally behind the plow. Soil lifted by the plow falls around the unfolded conduit constraining it to its unfolded configuration. A vehicle advances the plow and feeder through the ground. The feeder includes a surface for engaging the base of the conduit and guides for engaging the top. The surface and guides converge adjacent the outlet of the feeder to unfold the conduit passing inbetween. Further the surface and guides have arcuate portions that bend the conduit about its apex to urge it to its unfolded configuration.

Abstract: The specification discloses an apparatus and method for concurrently manufacturing at least two semiround tubing structures. An extruder including plasticizing means for a plurality of plastic resins extrudes semiround and linear strips of plastic material in generally two back to back D-shaped sleeves. Between the D-shaped sleeves, a strip of adhesively non-compatible material is extruded so that the D-shaped sleeves may be separated. The rounded portions of the D-shaped sleeves are molded in a continuous blow molding arrangement to form the top wall of the semiround tubing. The tubing is cooled, and the two semiround tubing lengths separated from the adhesively non-compatible strip inbetween. Optionally, the base of the semiround tubing may be perforated. The two lengths of semiround tubing are folded with the base inside the top wall and coiled into large reels.

Abstract: This application discloses a septic tank construction including an inlet baffle structure and an outlet baffle structure for reducing the turbulence in the liquid or clear zone of the septic tank. The tank has oppositely disposed arcuate end walls which bow outward. In one of the end walls is an inlet for receiving incoming raw sewage. Connected with the inlet is an inlet baffle structure for introducing the incoming sewage into the fluids in the tank with a minimum of turbulence. The inlet baffle structure comprises a generally tubular structure which is connected with the inlet and terminates in a fluid introducing flared opening disposed toward the end wall. The fluid introducing opening is oval in cross section with its major axis extending vertically. In the other end wall is an outlet for discharging treated fluids to the disposal field. An outlet baffle structure for receiving treated fluids to be discharged is connected with the outlet.

Abstract: A foldable conduit has a generally parabolic arched portion and a flat base. The arched portion comprises a pair of corrugated side walls which are connected with a hinge. The corrugations comprise alternating peak portions and valley portions. Each peak portion comprises a pair of generally vertical corrugation walls and a top wall connected with the corrugation walls. The top wall has a pair of ribs, each adjacent one of the pair of corrugation walls. Between the ribs is a recessed area. The ribs and recessed area are arcuate and generally undulating in cross section. The valley portion comprises an arcuate valley wall connected with the corrugation walls of adjacent peak portions. The flat base is a flexible sheet which may be perforated to permit fluid ingress and egress. The hinge and flexible base allow the side walls to be folded together with the base folded in between for more compact shipment.

Abstract: A corrugated, thin walled plastic tank is ideally suited for subterranean storage and transmission of sewage and other materials. The tank has a bottom wall which terminates in a peripheral edge disposed in a horizontal plane. A corrugated, peripheral wall extends upward from the peripheral edge to an apex area. The corrguations of the peripheral wall include alternating crown and root portions. A peripheral rib extending circumferentially around the peripheral wall is defined by a plurality of rib portions which are disposed in the root portions of the corrugations. Each rib portion has a rib outer portion which is substantially flush with the adjoining crown portions and rib side portions which extend from the rib outer portion into the adjacent root portion. An indentation area is formed by enlarging one of the root portions. An annular sleeve depends from the indentation area into the interior of the tank to provide a fluid access with the interior of the tank.

Abstract: This application discloses the method and apparatus for manufacturing plastic tubing which comprises a rigid semiround, triangular, or the like top section and a flat base of flexible sheet-like material. The manufacturing comprises the steps of or apparatus for (a) extruding a sleeve of thermoplastic material, (b) blow molding a corrugated generally tubular structure, (c) cooling the generally tubular structure, (d) splitting the generally tubular structure into a pair of semiround corrugated tubing structures, (e) bonding a strip of sheet-like material across the open base of the semiround tubing, (f) folding the semiround tubing longitudinally to a flattened configuration, and (g) coiling the tubing in its flattened configuration.

Abstract: An expandable core for handling and holding rolls of tubing. The core is comprised of support members connected to each other or a base extending along the longitudinal axis of the core by connecting links. The connecting links are pivotally attached at their terminal ends to the support members or the base rod to allow movement about a pivot assembly. Camming surfaces are mounted at the terminal ends of the support members and means for selectively expanding the core are adapted to engage the camming surface.

Abstract: A tee connector for coupling a corrugated tubing lateral normal to a larger diameter corrugated tubing main with a circular aperture in its side wall. The connector has a first end with a circular periphery sized to be received in the aperture. The first end is configured with two arcuate longitudinal recesses separated by two arcuate protuberances to conform with the interior surface of the main. Adjacent the first end are positioning projections which abut the exterior surface of the main to position the connector normal to the main. Also, adjacent the first end are tabs which are snapped through the aperture to engage the interior surface of the main. The lateral is received in a bore in the second end. The length that is received is limited by limiting projections in the bore adjacent the first end. Detents on the interior surface of the bore engage the corrugations of the lateral to inhibit its removal from the connector.

Abstract: A thin-walled, one-piece plastic tank for subterranean storage and transmission of sewage or other materials. The tank comprises a bottom wall, an arched top wall and opposed end walls. The top wall is substantially semi-circular in cross-section with a plurality of corrugations therearound. Along the apex area of the arch is a pair of manhole-like openings with an arced strengthening rib therebetween. The bottom wall is generally arced in cross-section with a radius very large compared to the radius of the cross-section of the top wall which causes the bottom wall to be generally flat. The end walls are arced in the longitudinal, cross-sectional and horizontal planes. The end walls each have a plurality of corrugations. In the root of one of the corrugations is a depression which contains a horizontal aperture for the egress or ingress of fluid materials. The bottom wall has a plurality of corrugations mating with the top wall corrugations such that the corrugations circumscribe the tank.

Abstract: A coupler structure which facilitates the internal joining of a first length of hollow plastic pipe having internal corrugations defined by a plurality of alternating peaks and valleys to a second length of similar pipe or to some other structure. The coupler is molded from plastic to have at least one cylindrical end portion dimensioned for longitudinal receipt in the second length of tubing or other structure which is to be coupled to the first length. This one end portion includes a plurality of integrally molded cleats extending generally radially outward thereof. The cleats are selectively movable between first locking positions for lockingly engaging the second tubing length valleys and second non-locking positions which permits forced insertion of the coupler one end portion into the second tubing length. The cleats are hinged to the one end portion generally laterally thereof and are continuously urged toward the first position by the resilient nature of the plastic construction.

Abstract: Disclosed is a foldable arched conduit suitable for use as drain tubing, culverts and the like. The conduit has the cross section of a parabolic arch with a flat base. The arched portion of the conduit comprises a pair of rigid corrugated plastic walls jointed at the apex area by a hinge. The base is constructed from a flexible sheet material which may contain apertures for liquid ingress and egress. For shipment, the rigid walls are folded inward about the hinge with the flexible sheet being folded between the rigid walls in order to present a generally flat configuration. After folding, the conduit may be conveniently rolled or length placed in parallel stacks for reducing the storage and/or shipping space required. At installation, the conduit may be unrolled along the installation site and then caused to expand into its unfolded shape.

Abstract: This application discloses a septic tank construction including an inlet baffle structure and an outlet baffle structure for reducing the turbulence in the liquid or clear zone of the septic tank. The tank has oppositely disposed arcuate end walls which bow outward. In one of the end walls is an inlet for receiving incoming raw sewage. Connected with the inlet is an inlet baffle structure for introducing the incoming sewage into the fluids in the tank with a minimum of turbulence. The inlet baffle structure comprises a generally tubular structure which is connected with the inlet and terminates in a fluid introducing flared opening disposed toward the end wall. The fluid introducing opening is oval in cross section with its major axis extending vertically. In the other end wall is an outlet for discharging treated fluids to the disposal field. An outlet baffle structure for receiving treated fluids to be discharged is connected with the outlet.