Product and method for sealing and lubricating sewer manhole assemblies

A sewer manhole cover includes a frame having an access aperture and a cover for covering the access aperture. A primary seal is generated when the cover is placed on the frame either by way of contact between the frame and cover or by way of a gasket received within a groove formed into one of the frame or cover, wherein the gasket is compressed between the frame and cover. A method is provided for generating a secondary seal between the frame and cover by applying an amount of a viscous compound to a circumferential surface of the frame or cover, wherein the secondary seal is formed when the cover compresses the compound when the cover is received within the frame.

TECHNICAL FIELD

The present invention relates to sewage collection and conveyance, and more particularly to manhole assemblies for accessing sewage pipelines and other underground utilities.

BACKGROUND

Most cities and municipalities own, operate, and maintain a network of sewage pipelines for transporting residential, commercial, and industrial wastewater to a central processing facility for treatment and disposal or reuse. Many cities and municipalities also have a separate system to convey rainwater and other surface water run-off for separate handling. Sewer manhole assemblies provide access to these underground pipelines. Sewer manhole assemblies often have an issue with the infiltration and inflow of rainwater, water run-off, and groundwater. Sewage pipelines are designed to handle wastewater at a peak or maximum amount—for example, if every shower were running and every toilet were flushed at the same time. However, surface and ground water infiltration and inflow into the sewer system can result in increased volume of fluid within the sewage system which can exceed the capacity of the sewer system. The increased flow in the sewer system due to surface and groundwater infiltration and inflow results in the need to sometimes oversize sewer handling facilities, increased energy costs to process the additional flows, backups into structures, and sanitary sewer overflows that can contaminate water bodies and present a public health risk. Thus, those that design the sewage systems typically increase the size and capacity of the sewage pipelines and handling facilities to account for additional water infiltration and inflow—sometimes doubling or tripling the size of the pipes for handling an unknown amount of extra fluid. This increased fluid handling capabilities of the sewage piping system results in significant cost increases to the municipalities. A need therefore exists for a method for sealing the manhole assemblies to reduce or eliminate the infiltration and inflow of rainwater and groundwater.

In addition, other problems associated with sewer manhole assemblies is worker injuries. Over time, manhole covers can become stuck to the frame such that it is difficult to remove the cover to access the sewer system. When the cover gets stuck, it often takes two workers to remove the cover wherein one worker uses a pick, pole, crow bar, or other lever to separate the cover from the frame. The second worker sometimes uses a hammer or other percussive tool to help separate the cover from the frame. However, the noise generated by the percussive contact between the hammer and the cover can cause hearing damage to the workers. Further, pushing the lever or attempting to lift a stuck cover can also cause back pain or damage to the worker as well.

A need therefore exists to provide a seal between a cover and frame of a sewer manhole assembly to prevent water infiltration and inflow. A need also exists to provide lubrication between a cover and frame of a sewer manhole assembly to make it easier to separate and remove the cover from the frame.

SUMMARY

In one aspect of the present invention, a method for creating a secondary seal for a manhole assembly is provided. The method includes providing a frame defining an access aperture therein and a cover received by the frame for covering the access aperture. The cover and the frame each having at least one circumferential surface. The method also includes providing a primary seal between the cover and the frame when the cover is received within the frame. The method further includes applying an amount of compound to one of the circumferential surfaces of the cover or one of the circumferential surfaces of the frame to generate a secondary seal between the cover and the frame.

This summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description section. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter. Furthermore, the claimed subject matter is not constrained to limitations that solve any or all disadvantages noted in any part of this disclosure.

DETAILED DESCRIPTION

Referring toFIGS.1-2, an exemplary embodiment of a manhole assembly10is shown. The manhole assembly10is configured to fit atop a cylindrical tube or shaft11, typically formed of concrete, which leads to the main sewer pipeline that leads to a sewage processing facility. A manhole assembly10can also be configured to fit atop a cylindrical tube or shaft11that leads to other underground utilities such as internet cables, telephone cables, electric cables, and the like to provide access to the underground utility lines. It should be understood by one having ordinary skill in the art that manhole assembly10can be utilized in a variety of different application, whereby the manhole assembly10provides access through a removable lid or cover. The manhole assembly10provides access through which a person can enter a vertical cylindrical shaft11. In the illustrated embodiment, the manhole assembly10includes a frame12and a cover14, wherein the cover14is received within and by the frame12. The frame12is configured to rest on or be attached to the vertical shaft11. The cover14is selectively removable from the frame12. In some embodiments, the cover14includes a pick hole16that is configured to receive a pick, pole, hook, or other lever to aid in leveraging the cover14during removal thereof from the frame12.

As shown inFIGS.1-2, the exemplary embodiment of the frame12is placed on the upper end of a vertical shaft11, wherein the vertical shaft11extends downwardly to the sewage lines, utility shafts, or the like. The frame12is a generally circular member defining an access aperture18defined centrally therethrough. The frame12includes a base20and a wall22integrally formed to the base20and extending at an angle therefrom. In the illustrated embodiment, the wall22extends from the base20perpendicularly, but it should be understood by one having ordinary skill in the art that the wall22can extend from the base20at any angle. The base20is an annular member having an outer circumferential edge24, a lower surface26, and an upper surface28. The lower surface26of the base20is configured to contact the upper surface of the shaft11. The base20extending laterally from the wall22forms a ledge, which is typically positioned below concrete or asphalt. The wall22extends upwardly from the base20, and similar to the base20, a portion of the wall22is typically surrounded by concrete or asphalt such that the upper edge of the wall22is exposed. The wall22includes an upper edge30and an inner surface32.

In an embodiment of the frame12, the wall22includes a notch34formed into the upper edge30and inner surface32, as shown inFIG.2. The notch34is generally L-shaped, wherein the notch34is configured to receive the cover14. The notch34is defined by a generally horizontal support surface36and a bearing surface38extending at an angle relative to the support surface36. In an embodiment, the bearing surface38is oriented perpendicular relative to the support surface36. In the illustrated embodiment, the bearing surface38extends from the support surface36at an angle larger than 90°. In some embodiments, the angle at which the bearing surface38extends from the support surface36is between about 90°-135°. Both the support surface36and the bearing surface38provide a circumferential surface—or an annular surface—that creates a complete circumference about the access aperture18. These circumferential surfaces provide surfaces to which a compound50can be applied to form a complete circumferential secondary seal between the cover14and the frame12, as will be explained in further detail below.

In the illustrated embodiment shown inFIGS.1-2, the cover14of the manhole assembly10is a disc-shaped member configured to be removably seated within the frame12. The cover14includes an upper surface40, a lower surface42, and a peripheral surface44that extends between the upper and lower surfaces40,42. The upper and lower surfaces40,42are oriented substantially parallel to each other, and the peripheral surface44is oriented at an angle relative to the upper and lower surfaces40,42. In an exemplary embodiment, the peripheral surface44is oriented at an angle between about 45°-90° relative to the lower surface42. In an embodiment, the angle of the peripheral surface44is substantially the same as the bearing surface38of the notch34formed in the frame12. A groove46is formed into the peripheral surface44about the entire circumference of the cover14. The groove46is configured to receive a gasket48. In an embodiment, the gasket48is formed as an O-ring, but it should be understood by one having ordinary skill in the art that the gasket48can be formed of any semi-flexible ring-shaped member having a continuous cross-sectional shape. In other embodiments of the cover14, the peripheral surface44is planar and does not include a groove for receiving a gasket. In further embodiments, the lower surface42includes a circular groove formed therein, wherein the groove receives a gasket configured to be positioned between the lower surface42of the cover14and the frame12to provide a primary seal therebetween. In other embodiments the frame12includes a circular groove formed in the surface that cooperates with the lower surface of the cover14, wherein the groove is configured to receive a gasket for providing a seal between the cover14and the frame12. It should be understood by one having ordinary skill in the art that a gasket can be connected to either the cover or frame (and at any location where the cover and frame would otherwise contact each other).

Both the peripheral surface44and the lower surface (the outer portion of the lower surface that contacts the support surface36of the frame12) provide a complete circumferential surface about the access aperture18. These circumferential surfaces provide surfaces to which a compound50can be applied to form a complete circumferential secondary seal between the cover14and the frame12, as will be explained in further detail below.

In the embodiments of the manhole assemblies10having a gasket48positioned between the frame12and the cover14, the gasket48provides a primary seal between the cover14and frame12. In the embodiments of the manhole assemblies10having no gasket positioned between the frame12and the cover14, the primary seal is formed between the cover and the frame through the abutting contact of the cover14and the frame12.

The exemplary embodiment of the manhole assembly10shown inFIGS.1-2is assembled by positioning the frame12atop a vertical shaft11. Once the frame12is secured, the gasket48is seated into the groove46of the cover14. The cover14is then lowered into the notch34formed in the frame12that is configured to receive the cover14. As the cover14is lowered onto the frame12, the peripheral surface44of the cover14aligns with the bearing surface38of the frame12and the gasket48contacts the bearing surface38. When fully seated, the peripheral surface44of the cover14contacts the bearing surface38of the frame12while the gasket48is compressed therebetween. In other embodiments, when fully seated, the peripheral surface44of the cover14is slightly spaced apart from the bearing surface38of the frame12such that the gasket48fills the gap therebetween to form the primary seal. In some embodiments, the lower surface42of the cover14contacts the support surface36of the notch34formed in the wall22of the frame12. The compressed gasket48is configured to provide a primary seal between the cover14and the frame12to prevent water inflow and infiltration through the manhole assembly10. However, the typical wear and tear of everyday use of the gasket48often results in pieces breaking off the gasket48or the ring itself to break, thereby creating gaps between the cover14and frame12that allows for rainwater and groundwater infiltration and inflow through the manhole assembly10. It should be understood by one having ordinary skill in the art that inflow of surface water between the frame12and cover14can occur when the frame12and cover14are not perfectly machined and matched or if grit gets worked between the frame and cover which prevents a complete seal therebetween.

For embodiments of a manhole assembly10having a cover14with a flat peripheral surface44that does not include a groove and corresponding gasket seated therewithin, the cover14is lowered onto the frame12such that the peripheral surface44of the cover14and the bearing surface38of the frame12as well as the lower surface42of the cover and the support surface36of the frame contact each other to provide a primary seal therebetween. In the embodiments of the manhole assemblies10that do not include a gasket, dirt and grit can work their way between the cover14and frame12, thereby compromising the seal therebetween which allows water infiltration and inflow. It should be understood by one having ordinary skill in the art that due to manufacturing tolerances and materials used, this manhole assembly10design typically allows much more rainwater and groundwater infiltration and inflow therethrough than the cover14that includes a gasket48.

FIGS.3-4illustrate a method for generating a secondary seal between the cover14and the frame12of a manhole assembly10. The method includes providing a manhole assembly10having a frame12configured to receive a cover14. The frame12includes a notch34formed into the wall22, wherein the notch34is defined by a support surface36and a bearing surface38that extends from the support surface36at an angle therebetween. The method further includes providing a cover14has an upper surface40, lower surface42, and a peripheral surface44extending between the upper and lower surfaces40,42. The method also includes providing a primary seal between the cover14and the frame12, wherein the primary seal can be formed by way of abutting contact between the cover14and frame12or by way of a gasket48positioned and compressed between the cover14and the frame. In an embodiment, the cover14includes a gasket48seated within a groove46formed into the peripheral surface44. In other embodiments, the cover14does not include a groove for receiving a gasket therein.

The method further includes depositing a quantity of compound50into the corner or intersection between the support surface36and bearing surface38of the notch34of the frame14. It should be understood that the compound50can be added to either the frame12or the cover14to generate a secondary seal when the cover14is placed on the frame12. In an embodiment, the compound50is deposited as a bead, or line of compound50. Such a bead of compound50can be deposited by way of a tube having a nozzle, wherein the compound50flows out of the nozzle to form a generally annular ring of compound50about the notch34. In other embodiments, the compound50is deposited as a generally amorphous quantity and spread onto the cover14or frame12into a circumferential manner. The compound50can be deposited by hand, using a trowel or scraper, or any other manner to deposit a quantity of compound50on the frame12to form a circumferential deposition of the compound. In order to provide the most effective secondary seal, the compound50is placed in the corner or intersection about the entire circumference of the notch34. As the cover14is lowered onto the frame12, the corner of the cover14formed at the intersection between the lower surface42and the peripheral surface44thereof contacts the quantity of compound50as the cover14compresses the circumferential deposition of the compound50. Because the compound50has a viscosity that allows it to flow, as the cover14is positioned in the notch34of the frame12which compresses the compound50, the compound50flows to fill the gaps, holes, or other spaces and vacancies between the cover14and the frame12below the gasket48. The result is a secondary seal is created between the frame12and the cover14to prevent infiltration and inflow of rainwater, groundwater, and water run-off through the manhole assembly10. It should be understood by one having ordinary skill in the art that the compound50can be applied to either the cover14or the frame12in order to create a secondary seal therebetween. It should also be understood by one having ordinary skill in the art that the compound50is applied in a continuous bead or amount about the entire annular surface of the cover14or frame12in order to prevent any sections or portions of the interface between the cover14and frame12from not having the secondary seal formed between them. It should further be understood by one having ordinary skill in the art that even if there are very small sections of the interface between the cover14and frame12that may be missing some compound50applied, the viscosity of the compound50is sufficient to flow or otherwise fill in small gaps as the cover14is seated on the frame12.

Manhole assemblies10are accessed in order to address issues within the sewage and/or utility systems connected thereto. When an operator needs access through the manhole assembly10, a pick, pipe, or other structure is inserted into the pick hole16of the cover14as a lever to separate the cover14from the frame12. Once the cover14has been removed from the frame12and all sewer and/or utility work is completed, the operator applies the compound50between the cover14and the frame12per the method described above before replacing the cover14on the frame12. For the first application of the compound50to the manhole assembly10, the operator should take care to ensure the compound is applied to the entire circumference of the frame12or cover14to ensure a complete secondary seal between the cover14and the frame12. After the first application of the compound50to the manhole assembly10when the manhole assembly is subsequently accessed, before the cover14is replaced on the frame12, the operator should observe the previous application of the compound50for any sections or portions that are missing or need re-applied. Further, if there is significant loss of compound50between the cover14and frame12due to everyday wear, additional compound50can be added to ensure a proper secondary seal. In addition, when there has been dirt or grime that has worked into the compound50in place between the cover14and frame12, the operator should use a rag, towel, or other cloth to remove as much of the previously-applied compound50and re-apply a fresh amount of compound50about the entire circumference of the cover-frame interface.

In addition to providing a secondary seal between the cover14and the frame12, the compound50is also configured to provide lubrication therebetween. The compound50provides a barrier between the frame12and the cover to prevent the components from rusting together if the manhole assembly10is not accessed regularly. Also, the viscosity of the compound50allows the cover14to slide, or otherwise move relative to the frame more easily, thereby reducing the strain on the operators as they try to lift or remove the cover14from the frame12. By providing a viscous barrier between the cover14and the frame12to lubricate the engagement therebetween, there will be a reduced number of injuries associated with the removal of the cover14from the frame.

In an embodiment, the compound50is a viscous material that can be easily applied to the frame12or cover14of the manhole assembly10. The viscosity of the compound50allows the compound to be stored in a tube, and applicator, or other similar applicators such that the operator is not required to physically apply the compound by hand. It should be understood by one having ordinary skill in the art that the compound50can also be applied by-hand, wherein the compound50is non-adhesive which prevents the compound from sticking to hands or gloves in an adhering manner during application. The compound50should be able to be easily wiped off the body and manhole assembly10components for easy clean-up.

The secondary seal generated by the compound50being applied between the frame12and the cover14means that this seal is in addition to the primary seal between the frame12and cover14that was not previously formed therebetween prior to the addition of the compound50. The secondary seal does not mean that it is the second barrier that any water run-off or groundwater contacts as it travels through the gap between the cover14and the frame12. In some embodiments, the secondary seal generated by the application of the compound50can be the first barrier encountered by water run-off or groundwater that flows through the gap between the cover14and the frame12.

While preferred embodiments of the present invention have been described, it should be understood that the present invention is not so limited and modifications may be made without departing from the present invention. The scope of the present invention is defined by the appended claims, and all devices, processes, and methods that come within the meaning of the claims, either literally or by equivalence, are intended to be embraced therein.