Abstract: A resilient annular transition collar is provided for roadway structures, including manholes and catch basins, which acts as a flexible transition between the rigid structure or frame of the manhole and the semi-rigid structure of the asphalt paving. The resilient transition collar absorbs any movement of the pavement during expansion and contraction and this absorption avoids the prior art problems of break-up, cracking and separation between manhole and pavement. Risers or adjusting rings may be employed in conjunction with the transition collar to ensure a flush fit between the pavement surface and the upper surface of the transition collar. A mold structure for forming the collars includes heat transfer studs to provide an increased production rate.

Abstract: A manhole base comprising a benching portion, an annular wall portion surrounding the benching portion and extending axially therefrom, the annular wall portion having inside and outside surfaces and at least two angularly spaced apart passages extending through the annular wall portion, each passage having inner and outer portions respectively, the inner and outer portions being disposed within the annular wall portion, the inner portions having respective inner openings in the inside surface and the outer portions having respective outer openings in the outer surface, the inner and outer openings being in communication with their respective passages. There is at least one canal in the benching portion for connecting at least two of the passages in communication with each other, the canal having an open top portion.

Abstract: A stackable height adjustment ring for supporting a manhole cover frame upon a concrete manhole shaft liner has a ring body that is formed from plastic resin, e.g., scrap plastic. The ring includes inner and outer radially spaced apart side walls and optionally a top wall. Brace arms which are integral with the walls preferably extend radially between the walls for holding them together. The rings have alignment members, e.g., an inner wall of the ring can have an upwardly facing shoulder upon its upper edge and the outer wall, a downwardly facing shoulder on its lower edge. An upwardly extending cylindrical collar at the top of the outer ring fits the downwardly facing shoulder of an adjacent ring. There is also a downwardly extending collar at the lower edge of the inner ring to fit on the upwardly facing shoulder of a similar inner ring.

Abstract: A fluid-tight tank is composed of a plurality of separate components. Each component is preferably formed from cement and provided with an interior region having a circular cross-section. Each component has a plurality of chase ways extending throughout its length. Post-tension cables are routed through these chase ways and are tightened so as to compress the components together so they act as one integral unit. Each component is has an annular flange-like protrusion and/or recess so that adjacent components can be aligned with one another while maintaining the circular cross-section quality throughout the entire length of the interior region. One or more of the components can be provided with a wall to separate one interior region with another.

Abstract: An underground storage system for hazardous liquids having an inner fluid storage tank surrounded by a larger outer containment vault with sufficient space between to allow for visual inspection of the tank. The inner tank has a rectangular parallelepiped shape and is positioned within an outer rectangular parallelepiped vault in a manner leaving a larger clearance space between two adjacent tank sides and facing vault walls than between the opposite adjacent two sides and walls. Additionally, a vertical clearance exists between the tank and vault. The vault is reinforced concrete precast in sections for ease of transport and assembly on-site. The vault has a bottom pan-shaped unit with one or more square tubular collar units on top and terminates in an upper cover. The cover includes one or more man-way apertures enabling a technician to enter the vault and inspect the tank for leaks. The increased use of excavated space for fluid storage reduces costs associated with transport and installation.

Abstract: A habitable structure has a ground-supported, water-impervious floor and upright foundation walls which together define an open top water enclosure. Flooring is supported on the foundation walls essentially covering the open top. Roofing is supported above the flooring so as to define a habitable space between the roofing and the flooring above the enclosure. Various systems for distributing water from the enclosure are disclosed and include the sprinkler system for distributing water outside as well as inside of the structure and heating/cooling systems which can either circulate water from the enclosure as a heat transfer liquid or circulate fluids through water in the enclosure to use the water as a heat sink or heat source.

Abstract: A manhole cover comprises a base and a cover. The base has a first inner rim provided with a first bevel while the cover has a second outer rim provided with a second bevel. When the base is joined with the cover, the first bevel of the base and the second bevel of the cover are caused to make contact with each other such that the base is joined with the cover in an airtight and watertight manner. The first bevel of the base and the second bevel of the cover are of such construction that they enable the cover to be lifted easily to set apart from the base.

Abstract: A drain inlet provides a hollow concrete shell and has a cylindrical bottom section and a square top section. A first opening in the bottom section includes a first lip formed on an interior wall thereof and recessed from the bottom opening. The first lip includes a first step and a second step. A gasket is adapted to fit within the bottom opening and abut the first step. The second step provides a stop for inserting the drain inlet over a riser. A second opening in the top section includes a second lip formed on an interior wall thereof and recessed from the top opening.

Abstract: A sewer chimney for connecting a surface branch sewer pipe to a deeply buried main sewer pipe having a fixture with an upwardly facing opening. The chimney is constructed of a plurality of precast concrete elements including a supporting base adjacent the main sewer pipe, one or more transitional sections on the supporting base and a cap block which rests on the upper most transitional section. An elongated vertical pipe extends from the fixture of the main sewer pipe to the cap block. Seals are provided between each of the concrete precast sections and seals are provided between the elongated vertical pipe and components of the construction.

Abstract: An adjustable manhole cover support frame that includes a base unit, a top support unit telescopically arranged on the base unit and screw jacks interconnecting the two units permitting selectively adjusting the relative telescopic position of the top unit on the base unit. The base unit has an open ended sleeve projecting upwardly from a flange utilized to secure the base unit to the top end of a manhole vertical conduit. The top support unit has a top annular plate from which depends three cylindrical walls defining a first outer cavity telescopically receiving the sleeve of the base unit and inwardly therefrom a second cavity with holes in the bottom to receive the upper ends of threaded bolts that provide the screw jacks for adjustment.

Abstract: A locking manhole insert to be placed under a conventional manhole cover to prevent unauthorized access to the manhole. The insert includes a plate-shaped disc with a plurality of locking radial arms mounted to its undersurface. The locking radial arms are securable in the extended position using a conventional padlock. The insert further includes apparatus for suspending equipment, such as pollution monitoring units, within the manhole opening.

Abstract: 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.

Abstract: A concrete well having an upper axial portion (10) decreasing in width axially from a larger bottom cross section to a smaller cross section at an upper opening of the well. The well includes an annular raiser (12) which is injection-molded of a plastic material and is located on the upper end surface (11) of the well surrounding said opening to extend the well axially upwards. The raiser has depressions (19) which extend in the peripheral direction of the raiser alternatingly on one side and the other of the raiser. The depressions are arranged in groups regularly spaced from each other by transverse solid portions (21) of the raiser. A well covering (13, 14) is supported on the raiser.

Abstract: A sewer chimney and method of forming a sewer chimney for connecting a surface branch sewer pipe to a deeply buried main sewer pipe having a fixture with an upwardly facing opening. The chimney is constructed of a plurality of precast concrete elements including a supporting base adjacent the main sewer pipe, one or more transitional sections on the supporting base and a cap block which rests on the upper most transitional section. An elongated vertical pipe extends from the fixture of the main sewer pipe to the cap block. Seals are provided between each of the concrete precast sections and seals are provided between the elongated vertical pipe and components of the construction.

Abstract: This invention relates to a modular frame which is made up of a suitable plastic material and is capable of giving the correct L-shaped profile to the upper edges of wells or of canalizations or of openings in general and is prepared so as to give the possibility of anchoring the same strongly to the cement mortar employed for its installation.

Abstract: An internal form with exterior surfaces corresponding to the interior surfaces of the access chamber adapted to be contacted by corrosive gasses; spraying such exterior surfaces of the form with a release agent and allowing the release agent to cure; spraying the cured release agent with a first layer of gel coat having a first color and allowing the gel coat to cure; spraying the cured first layer of gel coat with a second layer of gel coat having a second color contrasting to the first color and allowing the second layer of gel coat to cure; spraying the cured second layer of gel coat with resin and chopped strands to form a first fiberglass coating; attaching half cylinder pockets to the first fiberglass coating; spraying the first fiberglass coating and pockets with resin and chopped strands to form a second fiberglass coating; rolling the second fiberglass coating to remove air bubbles and to improve the bonding between the layers and coatings; laying up metal reinforcing rods interior of the pockets and

Abstract: A distributing box for laying a cable duct is dealt with in the construction field so that, after laying the cable duct, the box is sealed with mortar and then buried in the ground. Accordingly, the distributing box should desirably be set up in the construction field with ease. Underground water must not permeate the distributing box which has been buried in the ground. In the present invention, therefore, a distributing adapter which is mounted in the wall of a concrete box is constructed of a case which has a back plate, a partition wall which divides the interior of the case into a plurality of areas, a flange which is formed at the periphery of the case, and marks for drilling positions, which are put on the rear surface of the back plate.

Abstract: A habitable structure has a ground-supported, water-impervious floor and upright foundation walls which together define an open top water enclosure. Flooring is supported on the foundation walls essentially covering the open top. Roofing is supported above the flooring so as to define a habitable space between the roofing and the flooring above the enclosure. A catchment system collects rainwater from the roofing and other sources and conducts it into the enclosure where it is stored for future use. The enclosure formed by the foundation walls and floor is modified to permit use as either a water storage tank or habitable area itself.

Abstract: A manhole adjusting ring includes ring sections each having a vertically disposed connecting plate which is selected from an inventory of different sized connecting plates to interconnect an outer ring portion to an inner ring portion. The resulting adjusting ring section will compliment the dimensions of the manhole casting including the distance from the top peripheral edge to the casting ledge on the inner wall.

Abstract: An underground double containment system consists of a concrete outer containment receptacle housing a primary fluid flow pipe which extends therethrough and is slidably supported on double I-beam structures within the concrete receptacle. The concrete receptacle can be provided with a removable cover providing access to the primary piping in modular sections defined by the boundary of the receptacle. The primary piping can expand or move along the longitudinal axis of the concrete receptacle relative to the concrete receptacle enabling thermal of the primary and containment piping outside of the receptacle, which can be formed from different materials, as the outer containment pipe can be connected to the interior of the receptacle at the juncture of the receptacle and the primary piping. A plurality of concrete receptacles can be joined at an angle of between 0.degree. and 180.degree. to provide a double containment system for nonlinear primary pipes.

Abstract: A manhole rim and cover assembly includes a rim formed with an annular upwardly projecting lip extending around its central opening with a shoulder projecting radially inwardly from the lip at a location spaced below its upper edge. A cover has circumferentially spaced circumferential segments projecting downwardly from its lower surface to fit within the inner side of the lip and to rest upon the shoulder referred to above to prevent crushing of a sealing gasket received between the bottom of the cover and the upper edge of the lip. Vent openings are formed through the lip to vent the manhole when the cover is in place. Spring clips on the cover engage an undercut shoulder on the rim to releasably retain the cover against removal from the rim.

Abstract: A safety device for sealing a drain assembly including a plate element defining a basin with the drain assembly, a housing element depending from the plate element closed to an underground line associated with the drain assembly, and a seal element positionable between the plate element and drain assembly to provide a substantially fluid-tight seal therebetween when liquid fills the housing element interior.

Abstract: A cover assembly for a ground opening, such as a manhole or a storm drain, is disclosed. The cover assembly includes a frame having a top, a bottom and a tubular sidewall section which is open to both the top and the bottom of the frame. An abutment portion protrudes inwardly into the tubular sidewall section adjacent its bottom. A core is slidably insertable into the tubular sidewall section of the frame so that the bottom of the core abuts against the frame abutment portion. The core includes a tubular through opening adapted to receive and support a cover such as a manhole cover or a storm drain cover across its upper end. The frame is constructed of a metallic material while the core is constructed of a non-metallic material, such as plastic, to prevent seizing.

Abstract: A smoke chamber for a fireplace comprising both inclined (23, 24, 27, 28) and vertical (21, 22, 25, 26) supporting elements, each element having abutment surfaces (51) and supporting surfaces (34, 44) of such shape that a significant part of the load on the inclined elements is converted into a substantially vertical load on the vertical elements. The element built smoke chamber mounted on a burning chamber is immediately upon positioning capable of supporting a heavy brick chimney.

Abstract: A precast, prestressed concrete secondary containment vault comprised of a sloped, watertight bottom unit capable of holding a primary tank's entire contents, a collar unit sealed to the bottom unit by post-tensioned strands, top panels capable of supporting vehicles, a manhole providing access to permit direct inspection of the primary tank, and means for monitoring, ventilating and pumping the vault. Double-wall pipes for connecting the primary tank to external units and for directing any pipe leakage to the bottom unit are disclosed. The disclosed vault permits the use of less expensive, single-wall tanks which may be repaired in the vault or replaced by removing the top panels.

Abstract: A plastic shield which is generally rectangular and convex in shape is inserted into a storm drain to provide protection to a storm drain outlet from cleaning tools. The shield is constructed in two sections and is moveably connected to the storm drain to allow workman easy access to the storm drain outlet.

Abstract: The mortar cap receives cementitious materials therewithin, such as cement, mortar, and the like, to define a footing for a catch basin grating, and has a base frame with parallel, spaced-apart walls, and an ancillary frame also with parallel, spaced-apart wall. The base frame is set within the ancillary frame, and the latter is slidably and vertically displaceable relative to the base frame. The ancillary frame has a plurality of knobs projecting from wall surfaces thereof which confront given w=all surfaces of the main frame, and the given wall surfaces of the main frame has a plurality of racks of ribs. With vertical displacement of the ancillary frame, relative to the main frame, the knobs engage the ribs and, as a consequence, the ancillary frame is arrestingly held in the displacement.

Abstract: The mortar cap receives cementitious materials therewithin, such as cement, mortar, and the like, to define a footing for a manhole frame, and has a base frame with a pair of concentric, spaced-apart walls, and an ancillary frame, also with a pair of concentric, spaced-apart walls. The base frame is set within the ancillary frame, and the latter is slidably and vertically displaceable relative to the base frame. The ancillary frame has a plurality of knobs projecting from walls thereof which confront given walls of the base frame, and the given walls of the base frame has a plurality of racks of ribs which confront the knobs. With vertical displacement of the ancillary frame, or a sector of the ancillary frame, the latter is arrestingly held in the displacement due to an interference of the knobs and ribs, and an engagement of the knobs with a pair of the ribs.

Abstract: A seal and closure member of elastomeric material adapted to be cast in situ and comprising a cylindrical body portion and an integral frusto-conical skirt therewithin. A radially outwardly extending flange is embedded in adjacent concrete. The skirt has a knock-out web at its smaller diameter end portion and the seal and closure member may thus be employed selectively as closure members for apertures in distribution boxes and the like and as seals for pipes in communication with the box interiors. The seal also includes integrally formed bosses which allow a baffle to be secured directly thereon on the interior of the box opposite the end of a pipe in the seal.

Abstract: Method and apparatus for providing liners in manhole assemblies, which liner is comprised of a plurality of liner sections joined together to form the inner corrosion resistant surface of each manhole member. The liner section define the inner surface of the manhole member being molded. Cast material is poured into the mold and allowed to set. The liner surface engaging the cast material contains integral substantially T-shaped projections which anchor the liner sections to the cast member. The tops and bottoms of each liner section extend around the surface of the section engaging the next adjacent section joined thereto to prevent toxic materials from reaching a cast material. The liner sections are theroplastic vacuum formed whereby the sheet forming the liner section is drawn against substantially T-shaped strips arranged upon the mold member within the vacuum thermo-forming equipment to provide the aforementioned integral T-shaped anchoring projections.

Abstract: A seal and closure member of elastomeric material adapted to be cast in situ and comprising a cylindrical body portion and an integral frusto-conical skirt therewithin. A radially outwardly extending flange is embedded in adjacent concrete. The skirt has a knock-out web at its smaller diameter end portion and the seal and closure member may thus be employed selectively as closure members for apertures in distribution boxes and the like and as seals for pipes in communication with the box interiors.

Abstract: A top concrete section for a manhole assembly is cast with a plurality of bolt slot inserts each insert having a substantially inverted T-shaped hollow interior for slideably receiving a nut which may be moved to any desired position along the base of the insert for threadedly engaging a threaded rod employed to rigidly secure a cast iron cover frame to the top section.The method for casting a manhole top section comprises the steps of releasably mounting each insert within the mould assembly by means of a retaining slide which itself is slideably received within a pair of holding brackets provided on each of the inner and outer mould members, the insert being substantially fully closed on all sides thereof and having a top surface formed of a thin web which is easily fractured or cut away after the top manhole section is cast. The fully enclosed insert prevents any concrete from entering into the interior thereof.

Abstract: A manhole construction for assuring tightly sealing a manhole/sewer pipe connection. The heart of the invention resides in a molded elastomeric circular gasket for resiliently supporting a sewer pipe in a manhole opening and sealing the space between the wall of the opening and the surface of the pipe. The transverse cross-section of the gasket has a generally triangular head, with a forward face provided with an arcuate depressing therein, and a sloping rear face; a generally rectangular body, integral with the generally triangular head and generally "L" shaped leg depending from the body and coextensive with the rear face of the body, the leg of the "L" being directed towards the forward face.

Abstract: A system of modular precast encasement sections is provided to protect the outside drop of a manhole structure from damage due to weak ground support and to prevent leakage from said outside drop. Said precast encasement sections are stacked on top of a drop manhole base and on top of each other to a height sufficient to surround and support the outside drop tube. The stack of encasement sections is then capped off with a solid collar which has a circular opening of a diameter sufficient to receive the outside drop tube. This circular opening widens to form a shoulder which is adapted to receive and support thereon the lower most opening of a T-coupler for joining a supply line to the drop tube. The precast encasement sections, the solid collar, and the face of the manhole base which is to receive the stack of encasement sections are each provided with grooves on their upper faces and the solid collar and encasement sections are provided with coaligned projections along their lower faces.

Abstract: An adjustable cast iron or ductile iron manhole frame and method of construction utilizing a formed concrete base or a base of brick and cement mortar that supports both the frame and the pavement. The height and angle of the frame are determined by the method of construction which sets the height and angle of the formed concrete base. The frame is further adapted to receive and hold the manhole cover, and the frame includes an arched section to hold it securely to the concrete base or to filler material when in a raised position.

Abstract: Annular slab for closing the vessel of a fast nuclear reactor, comprising at least one downwardly divergent frusto-conical sleeve coaxial with the inner and outer sleeves delimiting the slab, dividing the slab envelope into upper and lower parts respectively filled with concrete incorporating metal reinforcements and with concrete for radiation protection.

Abstract: A concrete pressure vessel (1) for a nuclear reactor is formed with an arch (6) arranged above the cover (4) of the pressure vessel, said arch having a horizontally directed opening permitting horizontal transport of the cover. The cover (4) is retained by a plurality of compressive force transmitting elements (11) arranged between the cover and the arch (6).

Abstract: A closure for a prestressed high-pressure vessel comprises an anchoring ring surrounding the opening of the prestressed concrete pressure vessel, a plurality of axial stressing cables and a plurality of cover stressing cables. The cover is separately prestressed and simultaneously anchored to the prestressed concrete pressure vessel. The anchoring rings on the concret need for releasing the axial stressing cables of the prestressed concrete pressure vessel.

Abstract: The invention provides a storage tank comprising a storage tank main body of concrete; lining plates lined on inner surfaces of a bottom, side walls, and a ceiling of the storage tank main body; and a manhole of the ceiling which is air- and liquid-tight and which blocks radiation. Leakage detection ditches are formed within welded seams of the lining plates. A method for manufacturing such a storage tank is also provided.

Abstract: An apparatus for attaching a fluid line to a manhole includes a ring having an eccentric hole therein through which the fluid line passes. The ring is attachable in a circular mounting ring in the manhole whereby rotation of the ring adjusts the level at which the eccentrically located aperture is disposed and thus adjusts the height of entry of the fluid line. Sealing against fluid leakage is provided by a compression member which is compressed and sealed during attachment of the ring.

Abstract: Disclosed is a closing arrangement for large passages in a prestressed pressure vessel comprising a cover means for covering the opening of a passage in the prestressed pressure vessel, an annular structural part having an inner boundary surface surrounding the covering means at a distance and defining a space therebetween, a means for securing the annular structural part to the prestressed pressure vessel and a plurality of connecting elements disposed in the space between the annular structural part and the covering means in abutting relationship with the inner boundary surface of the annular structural part and the covering means.

Abstract: A preformed concrete unitary manhole base section is formed with a polygonal exterior wall with a plurality of substantially flat faces each aligned in a different direction. Some of the faces are formed with cylindrical openings into which standard drain conduit end portions closely fit. Compressible annular seals between the opening walls and the end portions effect a watertight seal between the section and the conduits. Interior flow contours are formed within the section between the openings. Separate plural handling and alignment facilitating means are formed in the exterior wall.

Abstract: Chimney for joining a lower main sewer line having a vertical nipple to an upper branch sewer line, the chimney consisting of a pre-cast concrete bridge assembly straddling the main line and having a bore through which the nipple extends, the bridge being joined by intermediate sections to a Y-branch section having passages and openings for joining it to the branch line, there being a fluid-tight seal between the bore and the nipple to permit relative movement therebetween without leakage.

Abstract: Plastic extender rings for manholes are produced and are seated on the top ring of a manhole by the use of caulking or other adhesive material. The manhole cover, which is elevated by the plastic ring or rings from the old pavement level to a new pavement level, renders the manhole cover less noisy to traffic and seated more evenly. Recessed or notched portions of the rings receive the asphalt to arrest rotational and upward movement of the rings. Composite adapter rings are provided to adapt an off size manhole top rings, to a standard size manhole cover. Plastics are employed which will not melt at the application temperature of asphalt but will soften somewhat to conform better to the contour of the manhole cover and/or underlying manhole top ring.

Abstract: The Mortar Cap Form, according to the embodiment shown, comprises a plastic-preformed form in which to pour cement or mortar, to define a rectilinear footing for a catch basin. The form, in its basic configuration, presents channels, of right-angular juncture, defined by parallel walls of uniform width. in order to properly align the form with the top course of a catch basin, locating pins project downwardly from a bottom portion of the form, and from inner corners thereof, to pilotingly engage the catch basin course. The parallel walls are spaced apart by a series of traversing ribs; the ribs strengthen or reinforce the walls, and have voids formed therein to accommodate a flow of cement or mortar therethrough. In its supplemented configuration, the Mortar Cap Form includes a second form of parallel walls which also define channels for receiving cement or mortar, but the second form has tapered walls--to complement inclined road surfaces.

Abstract: A frame and cover for an underground fire hydrant, especially adapted for use in locating a fire hydrant in a highway, preferably at an intersection, and by means of which the fire hydrant is rendered readily accessible for use.

Abstract: A manhole well structure for gaining access to an underground water main, a sewer pipe system or the like, which includes a preferably precast base, made of concrete or like material, which is disposed at an appropriate depth below the ground level. The base element has an appropriate thickness so as to provide a strong and sturdy base for the manhole well wall structure, and is provided with a generally centrally disposed transverse groove in which is disposed the water main or sewer conduit, and with an annular recess or groove formed proximate the periphery of the base and providing an anchoring and footing means for the bottom of the well wall.

Abstract: A catch basin cover and lid takes the form of a reinforced concrete slab-like body of a desirable shape and provided with a central opening and a lid and replaces the cast iron catch basin covers heretofore generally employed. The reinforcing members are shaped to support the peripheral edges of the concrete slab and are positioned transversely therein so as to engage and support a reinforcing ring defining the access opening in the cover, the reinforced concrete catch basin cover and lid are uniformally sized by formation of the same in an appropriately shaped outline mold uniformly spaced with respect to the reinforcing members of the catch basin cover.

Abstract: A process for raising manholes and manhole covers to a new grade level of a street when constructing new streets or when paving old streets, comprising the steps of placing a sealing means around the interior of the cast manhole between the lower edge thereof and the upper edge of a sewer catch basin, and pouring wet concrete around the exterior of manhole, the sealing means, and the upper edge of the sewer catch basin to form a continuous joint between the manhole at the raised grade level and the upper edge of the sewer catch basin, and removing the sealing means from between the edges of the manhole and sewer catch basin.

Abstract: A manhole closure for diverting liquid away from a sewer system that is readily installable in a conventional manhole opening beneath a manhole cover, the device including two-way pressure relief valves to compensate for increased or decreased system pressure (relative to atmospheric) within the manhole system while preventing excessive amounts of rainwater and the like, chemical spills or other undesirable pollutants from entering the sanitary sewer system. The two-way valve system includes upper and lower counterweighted flapper valves which sealably cover passages within the closure housing. A valve supporting plate is enclosed in a cylindrical housing and includes upper and lower strainers, the housing being readily mountable in a conventional manhole opening by a rigid supporting rim affixed to the housing. The device will divert liquid flow away from a sanitary sewerage system while preventing over or under gas pressure conditions from developing within the system.