 Extension ladder |
| I claim: 1. An extension ladder comprising a first metallic ladder portion supportable on the ... |
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| Braking apparatus |
| What is claimed is: 1. A braking apparatus for vehicles having one or more sets of wheels mounted ... |
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| Overstrike ribbon for print wheels |
| We claim: 1. An overstrike ribbon capable of being advance with each printing of a letter between a ... |
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| Building roof structure |
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| Shellfish meat and shell separation process and apparatus |
| What is claimed as new and what it is desired to secure by Letters Patent of the United States is: 1... |
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| Vaulted underground storage tank |
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| Ladder fastening device for pole climbing |
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| Roof saddle |
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| Post |
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| Semiconductor polishing pad |
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Lined structure and liner
| Details |
Inventors: Strickland, James K.;
Assignee: Strickland Industries, Inc. (Jacksonville, FL)
Primary Examiner: Ridgill, Jr.; James L.
Assistant Examiner:
Attorney, Agent or Firm: Banner, Birch, McKie & Beckett
A plastic liner for protecting concrete manhole interior surfaces from corrosion wherein the liner includes provisions for creating a strong mechanical lock between the liner and the interior surfaces. A side of the liner which includes the provisions has a plurality of raised hollow projections with spaced sections. The mechanical lock is created when concrete is poured against the side of the liner with the projections. The concrete at least partially enters the hollow portions and fills spaces between the projection sections. The projections also intersect to enhance the mechanical lock by preventing bulging. Liner sections cover essentially all of the manhole interior surfaces. Forming a liner section by rotationally molding the plastic and cutting gaps into the projections is also disclosed. |
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DETAILED DESCRIPTION OF THE INVENTION Manhole Assembly FIG.
5 shows a manhole structure 100, hereinafter referred to as a manhole, mainly comprised of a base section 110, a riser section 120, a top section 130, concrete spacers 140, grade rings 150, a circular support flange 160, a manhole cover 170, and an insert 400.
Base section 110 includes a floor 112 and a cylindrical side wall 114 having at least two circular holes 116 and a top surface 118.
Floor 112 includes a bench 115 and a channel or channels 113, the bottom of which is referred to as an invert 117.
There are typically one, two or three inlet pipes 180 which carry sewage into manhole 100 and one outlet pipe 190 for carrying sewage away from manhole 100.
FIG.
6 shows two inlet pipes 180 carrying sewage into manhole 100.
The number of holes 116 in base wall 114 is equal to the sum of the inlet and outlet pipes 180, 190, as there is one hole 116 in base wall 114 for each pipe.
Each pipe extends into manhole 100 or abuts with a shoulder in the manhole wall 114, and mates with an end of a channel 113 in floor 112 of base section 110.
A fitting assembly 300, which is explained in detail hereinafter, connects each pipe 180, 190 to manhole 100.
Riser section 120 is a right cylindrical unit having a wall 122 with a top surface 124 and a bottom surface 126.
Top surface 118 of base section 110 mates with bottom surface 126 of riser section wall 122 forming a continuous inner surface.
Top section 130 is a conically shaped member having and angled wall section 132 and a straight wall section 134.
The shape of top section 130 maintains the continuity of the interior wall surface between riser section 120 and spacers 140 and concrete ring 150.
Top surface 124 of riser section 120 mates with a bottom surface 136 of top section wall 132, 134, while top surface 138 of top section 130 abuts with the bottom 142 of spacers 140.
In sewer designs where sewer pipes 180, 190 are located far below the street level, as indicated by manhole cover 170, more than one riser section 120 may be required
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Gutter-related 
