Patent Application
20070116518
Not Applicable
Not Applicable
1. Field of the Invention
The present invention relates to articles for internally sealing a chimney of a manhole against ground water infiltration, and more particularly to mechanisms by which the seal is attached to the manhole.
2. Description of the Related Art
A typical manhole includes a main chamber or barrel section to which the sewer pipes connect. That section is topped with a conical riser in which the diameter reduces going upward to a size needed to fit a metal frame for the manhole surface opening. The metal frame receives the manhole cover and either sits directly on top of the riser or there may be one or more vertical adjusting rings there between, as needed to raise the top of the frame level with the surrounding surface. Adjusting rings usually are formed by annular precast concrete sections or courses of bricks or blocks. This combination of components is referred to as a “chimney”.
During construction of the manhole, the joints between the chimney components are sealed with mortar or other material to prevent surface water infiltration. Nevertheless, movement of the metal frame, resulting from expansion and contraction due to seasonal temperature changes and from vibration as vehicles pass over the manhole, causes cracks to form at those joints. As a result, ground water from rain and snow is able to enter the manhole through these cracks. Such ground water infiltration is undesirable for sanitary sewers, as it increases the volume of effluent which has to be processed by a sewage treatment plant. Municipalities go to great lengths to minimize the inflow and infiltration of ground water into sanitary sewers.
As a consequence, different external and internal sealing systems have been devised to prevent ground water infiltration into manholes. One type of an internal sealing system is described in U.S. Pat. No. 4,469,467 and utilizes a resilient sleeve that is inserted into the manhole chimney and held against the inside surface by upper and lower metal fastening bands.
An assembly is provided to internally seal a manhole against infiltration of water, wherein the manhole includes an inwardly projecting flange.
The assembly comprises a sleeve made of a resilient material which includes a first sealing section and a second sealing section. The first sealing section has a recess for receiving the flange to attach the sleeve to the manhole. In a preferred embodiment, the first sealing section is formed with a hook-like lip that creates the recess and the resiliency of the sleeve enables the lip to engage the flange in a manner that provides a watertight seal.
A fastening device engages the second sealing section of the sleeve and presses an outer surface of the sleeve against a surface of the manhole, thereby providing another watertight seal. The preferred embodiment of the fastening device comprises a fastening band that has first and second end portions which overlap and a mechanism that adjustably secures those end portions together to form a loop. For example, the first end portion has a tab and the second end portion has a plurality of slots that cooperate with the tab to connect the first and second end portions together in the loop.
Another aspect of the assembly provides a pleated section between the first and second sealing sections to allow the sleeve to expand and contract with movement of the parts of the manhole without breaking the watertight seals.
With initial reference to
The metal frame 18 has an opening 22 by which a person gains access to the interior of the manhole 10. An interior, annular flange 24 extends around the interior of the opening 22. A manhole cover 26 is shown closing the upper portion of the opening 22 above the annular flange 24. The cover 26 is dropped in place and the annular flange 24 prevents the cover from falling completely through the opening 22.
An internal chimney seal 30 is attached inside the manhole 10 to provide a watertight barrier at the joints between the manhole frame 18, the adjusting rings 16, and the riser 12, thereby blocking ground water infiltration. The seal 30 consists of a tubular sleeve 32 that preferably is constructed of rubber or a similar resilient material that is extruded as a strip. The extruded strip is cut to a length that corresponds to the circumference of the finished sleeve and the ends then are sealed together with a suitable adhesive, for example. The exemplary sleeve 32 has two central pleats 33 and 34 located in between cylindrical sealing sections 35 and 36 at opposite ends of the sleeve. The pleats 33 and 34 allow the sleeve to expand, thereby accommodating vertical movement of the manhole components. Additional pleats or a straight section may be placed between pleats 33 and 34 to provide a sleeve that is able to span taller manhole chimneys.
With reference to
In addition to providing a watertight seal to the manhole chimney frame 18, the lip 40 of the sleeve 32 also acts as gasket between the manhole cover 26 and the chimney frame to prevent water infiltration through that seam. As seen in
Referring to
The fins 50 of the lower sealing section 36 are held against the inner surface of the manhole 10 by a stainless steel fastening band 48 that is received in an annular groove on the inner circumferential surface 46 of the lower sealing section 36. The fastening band 48 has overlapping end portions 51 and 52 which are slidable with respect to each other, as shown in
Referring to
The foregoing description was primarily directed to a preferred embodiment of the invention. Although some attention was given to various alternatives within the scope of the invention, it is anticipated that one skilled in the art will likely realize additional alternatives that are now apparent from disclosure of embodiments of the invention. Accordingly, the scope of the invention should be determined from the following claims and not limited by the above disclosure.
