A toilet bowl unit includes a toilet bowl with an inner toilet bowl surface having an upper peripheral portion, a central peripheral portion and a lower sump portion. A peripheral slot separates a lower edge of the upper peripheral portion from an upper edge of the central peripheral portion. A peripheral water channel is concealed inside the toilet bowl unit and has a side wall which is a weir over which water may flow into the peripheral slot. The slot has a discharge opening which is substantially horizontal at the rear and sides of the inner toilet bowl surface (for discharging a curtain of water) and includes at least one serpentine portion at the front of the inner toilet bowl surface (for discharging a jet of water). The horizontal portion(s) of the discharge opening are positioned just below a seat platform surface in order to minimize the unwashed area at the top of the inner toilet bowl surface.

A flush toilet for cleaning a toilet main body and discharging waste by using flush water is disclosed. The flush toilet contains a bowl portion including a bowl shaped waste-receiving surface and a rim portion formed on a top edge of the waste-receiving surface, the rim portion having an inner circumferential surface whose top portion is configured to rises vertically. The bowl portion contains a front region, the front region includes a first arc-shaped surface having a curvature R1 in a horizontal direction of a top portion of the waste-receiving surface and a second arc-shaped surface having a curvature R2 in a vertical direction formed by the inner circumferential surface of the rim portion and the waste-receiving surface, and the ratio of the curvature R1 to the curvature R2 is in a range of 1:3 to 3:1.

A flush toilet for cleaning a toilet main body and discharging waste by using flush water is disclosed. The flush toilet contains a bowl portion including a bowl shaped waste-receiving surface and a rim portion formed on a top edge of the waste-receiving surface, the rim portion having an inner circumferential surface whose top portion is configured to rises vertically. The bowl portion contains a front region, the front region includes a first arc-shaped surface having a curvature R1 in a horizontal direction of a top portion of the waste-receiving surface and a second arc-shaped surface having a curvature R2 in a vertical direction formed by the inner circumferential surface of the rim portion and the waste-receiving surface, and the ratio of the curvature R1 to the curvature R2 is in a range of 1:3 to 3:1.

A modular toilet is disclosed comprising a toilet shell and a hydraulic core. The hydraulic core module is a separate unit from the toilet shell module and may be non-symmetrical with the internal and external form of the shell. The core module comprises a toilet bowl connected to a siphon drain comprising a weir. The drain may be a vertical loop drain. The toilet shell and the hydraulic core may comprise mutual sealing surfaces. The drain may comprise openings for connection to a toilet ventilation system.

A modular toilet is disclosed comprising a toilet shell and a hydraulic core. The hydraulic core module is a separate unit from the toilet shell module and may be non-symmetrical with the internal and external form of the shell. The core module comprises a toilet bowl connected to a siphon drain comprising a weir. The drain may be a vertical loop drain. The toilet shell and the hydraulic core may comprise mutual sealing surfaces. The drain may comprise openings for connection to a toilet ventilation system.

A siphonic flush toilet system and method of priming the same having a toilet bowl assembly comprising at least one jet flush valve assembly and at least one rim valve; and bowl having a rim and a jet defining at least one jet channel, the at least one jet channel having an inlet port and a jet outlet port configured for discharging fluid to a sump area, wherein the sump area is in fluid communication with a trapway. The bowl has a closed jet pathway including the jet channel and extending from the jet flush valve assembly outlet to the jet channel outlet port to maintain the jet channel in a primed state with fluid from the jet flush valve assembly so as to assist in preventing air from entering the closed jet pathway. Flush valves are also disclosed having back-flow preventer mechanisms and/or at least partly flexible valve covers for use with the toilet systems and methods herein.

A siphonic flush toilet system and method of priming the same having a toilet bowl assembly comprising at least one jet flush valve assembly and at least one rim valve; and bowl having a rim and a jet defining at least one jet channel, the at least one jet channel having an inlet port and a jet outlet port configured for discharging fluid to a sump area, wherein the sump area is in fluid communication with a trapway. The bowl has a closed jet pathway including the jet channel and extending from the jet flush valve assembly outlet to the jet channel outlet port to maintain the jet channel in a primed state with fluid from the jet flush valve assembly so as to assist in preventing air from entering the closed jet pathway. Flush valves are also disclosed having back-flow preventer mechanisms and/or at least partly flexible valve covers for use with the toilet systems and methods herein.

A toilet seal for sealing between a plumbing fixture discharge and a waste drainpipe outlet is described. The toilet seal comprises a flange member having an inwardly extending flexible lip and one or more raised ridges defining an annular seal extending upwardly from an upper surface of the flange member. The toilet seal further includes a radiused wall extending downwardly from the flange member, which cooperates with the flange member to define a cavity for receiving a compressible member. The toilet seal further comprises a flexible sleeve extending downwardly from the radiused wall. Related methods are described.

A flush toilet wherein the rim inside wall portion comprises a rim inside wall upper sloped surface, and an improvement in user visibility and user rim portion cleanability is sought, flush water can be constrained from splashing outside the bowl portion by traveling by centrifugal force along the rim inside wall upper sloped surface from the inside surface formed at a relatively low height. The rim portion of the flush toilet of the invention includes a rim inside wall portion; the rim inside wall portion comprises a rim inside wall upper sloped surface, and an inside surface vertically extending straight up to the rim inside wall upper sloped surface; and the water supply apparatus comprises a constant flow rate valve for spouting a predetermined constant flow rate of flush water from the water spouting portion.

A flush toilet wherein the rim inside wall portion comprises a rim inside wall upper sloped surface, and an improvement in user visibility and user rim portion cleanability is sought, flush water can be constrained from splashing outside the bowl portion by traveling by centrifugal force along the rim inside wall upper sloped surface from the inside surface formed at a relatively low height. The rim portion of the flush toilet of the invention includes a rim inside wall portion; the rim inside wall portion comprises a rim inside wall upper sloped surface, and an inside surface vertically extending straight up to the rim inside wall upper sloped surface; and the water supply apparatus comprises a constant flow rate valve for spouting a predetermined constant flow rate of flush water from the water spouting portion.