Abstract: Manhole inserts suitable for deployment in a manhole opening of a manhole structure may include a manhole insert bottom. A manhole insert sidewall may extend from the manhole insert bottom. A manhole insert flange may extend from the manhole insert sidewall. A manhole insert gasket may be on the manhole insert flange, The manhole insert gasket may include a solidified, hardened, and cured gasket material having a synthetic silicone elastomer. The manhole insert gasket may be configured to remain exposed on the manhole insert flange prior to deployment of the manhole insert in the manhole opening of the manhole structure.

Abstract: Methods of fabricating a manhole insert gasket on a manhole insert flange of a manhole insert may include inverting a manhole insert having a manhole insert flange; forming a manhole insert gasket by dispensing a liquid gasket material onto the manhole insert flange along at least one circular dispensing path, the liquid gasket material including a synthetic silicone elastomer; and curing the gasket material.

Abstract: Methods of fabricating a manhole insert gasket on a manhole insert flange of a manhole insert include fabricating a gasket mold, inverting a manhole insert having a manhole insert flange, placing the manhole insert on the gasket mold with a mold space overlying the manhole insert flange, preparing a gasket material, placing the gasket material in the mold space, finishing the manhole insert gasket by curing the gasket material and removing the manhole insert from the gasket mold. Manhole inserts having a manhole insert gasket characterized by enhanced sealing capability and longevity are also disclosed.

Abstract: Methods of fabricating a manhole insert gasket on a manhole insert flange of a manhole insert include fabricating a gasket mold, inverting a manhole insert having a manhole insert flange, placing the manhole insert on the gasket mold with a mold space overlying the manhole insert flange, preparing a gasket material, placing the gasket material in the mold space, finishing the manhole insert gasket by curing the gasket material and removing the manhole insert from the gasket mold. Manhole inserts having a manhole insert gasket characterized by enhanced sealing capability and longevity are also disclosed.

Abstract: Sewer gas sampling and analyzing devices include a dish-shaped manhole insert having a manhole insert interior and a manhole insert exterior outside the manhole insert interior; a manhole insert vent valve carried by the manhole insert, the manhole insert vent valve having a valve inlet disposed in fluid communication with the manhole insert exterior and a valve outlet and the manhole insert vent valve facilitates substantially unrestricted flow of gas from the valve inlet to the valve outlet; and a gas detector unit disposed in fluid communication with the valve outlet of the manhole insert vent valve. Sewer gas sampling and analyzing methods are also disclosed.

Abstract: A manhole cover assembly includes a manhole structure, a manhole frame carried by the manhole structure and a manhole frame grout cementing the manhole frame to the manhole structure. The manhole frame grout includes a grout mixture having an epoxy resin, a curing agent and an aggregate. The epoxy resin and the aggregate are present in the grout mixture in an epoxy resin:aggregate weight ratio of about 0.09. A removable manhole cover is carried by the manhole frame. A manhole cover assembly fabrication method is also disclosed.

Abstract: A watertight manhole insert and tether locking apparatus and method of use designed to prevent unauthorized entry into a sanitary sewer or other closed drainage system through a manhole closed by a manhole cover. The manhole insert is located beneath the manhole cover and is connected to the manhole by a tether apparatus in the manhole to prevent water entry into the manhole, theft of the manhole insert and to deny access to the manhole. The manhole insert includes a pan-shaped insert body having pressure-relief valve and a lift strap and a side wall fitted with a top rim for engaging a shoulder shaped in the manhole, to support the manhole insert in the manhole.

Abstract: A watertight manhole insert and tether locking apparatus and method of use designed to prevent unauthorized entry into a sanitary sewer or other closed drainage system through a manhole closed by a manhole cover. The manhole insert is located beneath the manhole cover and is connected to the manhole by a tether apparatus in the manhole to prevent water entry into the manhole, theft of the manhole insert and to deny access to the manhole. The manhole insert includes a pan-shaped insert body having pressure-relief valve and a lift strap and a side wall fitted with a top rim for engaging a shoulder shaped in the manhole, to support the manhole insert in the manhole.

Abstract: A watertight manhole insert and tether apparatus designed to prevent rainwater from entering sanitary sewer or other systems through a manhole closed by a manhole cover. The manhole insert is located beneath the manhole cover and is connected directly to the manhole by a tether apparatus mounted in the manhole, to plug the manhole, prevent theft of the manhole insert and deny access to the manhole. The manhole insert is characterized by a pan-shaped insert body having a curved, flat or ribbed insert bottom and one or more pressure-relief valves, one or more lift straps and an upward-standing, sloping or perpendicular side wall fitted with an outwardly-extending top rim for engaging a shoulder shaped in the manhole to support the manhole insert in the manhole.

Abstract: A watertight manhole insert and tether apparatus designed to prevent rainwater from entering sanitary sewer or other systems through a manhole closed by a manhole cover. The manhole insert is located beneath the manhole cover and is connected directly to the manhole by a tether mounted in the manhole, to plug the manhole and prevent theft of the manhole insert. The manhole insert is characterized by a pan-shaped insert body having a flat insert bottom and a pressure-relief valve, one or more lift straps optionally provided with a warning tag, and an upward-standing, sloping or perpendicular side wall fitted with an outwardly-extending top rim for engaging a shoulder shaped in the manhole to support the manhole insert. One end of the flexible stainless steel tether is connected to the manhole wall and the opposite end first extends through a grommet in the insert bottom and subsequently through a lever bar locking device.

Abstract: A method and apparatus for sealing manholes which includes the installation of a donut-shaped seal structure in the chimney, cone or base of a manhole at a selected distance from the manhole cover and seating a dish-shaped manhole insert in an opening provided in the seal structure to define a manhole seal. The seal structure element of the manhole seal is installed by initially mounting a flexible form base to the chimney, the concentric or eccentric cone or the base of a manhole by means of anchor bolts and masonry anchor plugs. A flexible form is then seated on the form base and concrete is poured in the annulus between the form base and the chimney wall, in order to define the seal structure. A manhole insert seal may then be seated in the top surface of the seal structure for receiving the flange or rim of the manhole insert component of the manhole seal.

Abstract: A watertight manhole insert which is characterized by a dish-shaped seal or stopper designed to prevent rainwater from entering a sanitary sewer system through a manhole closed by a manhole cover. The manhole insert is located beneath the manhole cover and serves to plug the manhole and prevent flooding of the underlying sewer system. The manhole insert is characterized by a dish-shaped bowl having a pressure-relief valve, an optional vacuum relief valve and left strap and a substantially perpendicular, upward-standing side wall fitted with an outwardly-extending top rim for engaging a shoulder shaped in a manhole to support the manhole insert. Multiple, upward-standing bottom ribs radiate from the side wall inwardly in the curved bowl bottom toward the pressure relief valve, which is normally located in the center of the manhole insert, in order to stiffen the bowl-shaped bottom. Optional side ribs may also be provided in the vertical side wall for stiffening purposes.