A plastic article useful as a riser assembly for a septic tank or as part of another structure is comprised of a multiplicity of identical shape conical wall plastic risers. The risers are attached to each other at joints by tabs which engage rim segments; each end of the riser has alternating tabs and rim segments. A riser assembly wall undulates in the lengthwise direction. The risers nest within each other for shipment or storage.

The present invention relates to a storage tank, comprising a neck portion having an opening, the neck portion having side walls which define a first storage volume; a body portion connected to, and located below, the neck portion, the body portion having side walls and a base which define a second storage volume, wherein a section of the body portion is configured with a substantially rectangular cross-section in the horizontal plane, and wherein the second storage volume is greater than the first storage volume; and ribs projecting generally radially from the side walls of the neck portion and/or the body portion.

A safety grating has an arch shape cross section and is useful within a riser having a frusto-conical shape wall which riser is attached to a septic tank or another structure. The grating comprises a hub and radially extending arms, one or more of which is rotatable relative to the hub length at a hinge joint, to decrease the size of the grating and enable installation of the grating by passing the grating a smaller end opening of a riser.

A plastic article useful as a riser assembly for a septic tank or as part of another structure is comprised of a multiplicity of identical shape conical wall plastic risers. The risers are attached to each other at joints by tabs which engage rim segments; each end of the riser has alternating tabs and rim segments. A riser assembly wall undulates in the lengthwise direction. The risers nest within each other for shipment or storage.

The present invention relates to a storage tank, comprising a neck portion having an opening, the neck portion having side walls which define a first storage volume; a body portion connected to, and located below, the neck portion, the body portion having side walls and a base which define a second storage volume, wherein a section of the body portion is configured with a substantially rectangular cross-section in the horizontal plane, and wherein the second storage volume is greater than the first storage volume; and ribs projecting generally radially from the side walls of the neck portion and/or the body portion.

A sump pump crock includes a body including a first portion and a second portion separate from the first portion. The first portion includes one of a tab and an opening, and the second portion includes the other of the tab and the opening. The tab is received in the opening to secure the first portion to the second portion. The body defines a base, a plurality of sidewalls, and a top opening, and a plurality of flanges extend around an outer perimeter of the body. The sump pump crock includes a removeable lid that covers the top opening.

A form for a plastic lined septic system distribution box is configured to receive a fill material. The form includes a jacket, a plastic core, a plastic inlet ring, and a plastic outlet ring. The jacket defines an exterior wall and exterior floor of the distribution box. The core defines an interior wall interior floor of the distribution box. The inlet portal ring and outlet portal ring extend between the core interior wall and the jacket exterior wall. The core and jacket are arranged to leave a space therebetween to receive the fill material, and the core is configured to serve as the interior wall and interior floor of the distribution box and to line the fill material for the distribution box during use.

A prefabricated former for an underground pump station comprises: a floor former; a plurality of vertical support elements; a side wall secured to and surrounding the plurality of vertical support elements, the side wall having an inner layer and an outer layer defining a cavity therebetween, and an opening at an upper end of the side wall in communication with the cavity for receiving concrete, the side wall extending both above and below the floor former for defining a space above the floor former and a space below the floor former, and an opening being provided between the cavity and the space below the floor former enabling concrete to flow through the cavity and into the space below the floor former; when set, the concrete forming a unitary wall and base.

A safety grating has an arch shape cross section and is useful within a riser having a frusto-conical shape wall which riser is attached to a septic tank or another structure. The grating comprises a hub and radially extending arms, one or more of which is rotatable relative to the hub length at a hinge joint, to decrease the size of the grating and enable installation of the grating by passing the grating a smaller end opening of a riser.

A prefabricated former for an underground pump station comprises: a floor former; a plurality of vertical support elements; a side wall secured to and surrounding the plurality of vertical support elements, the side wall having an inner layer and an outer layer defining a cavity therebetween, and an opening at an upper end of the side wall in communication with the cavity for receiving concrete, the side wall extending both above and below the floor former for defining a space above the floor former and a space below the floor former, and an opening being provided between the cavity and the space below the floor former enabling concrete to flow through the cavity and into the space below the floor former; when set, the concrete forming a unitary wall and base.