Vacuum assist toilet trap

A vacuum assisted toilet which includes a toilet bowl, a bowl outlet that has upper and lower traps and a trapway between said traps, and a source that flows water into said bowl at the beginning of a flushing and a vacuum source that applies a vacuum to said trapway during a flushing, characterized by:

• said bowl outlet has a centerline and upper and lower walls at said lower trap, said lower wall forming a container to hold a pool of water that has a pool top, with said container having a downstream end lying at the level of said top of said pool of water, and said upper wall forming an air passage that lies above said pool top, with said upper wall having an air passage top wall with a lowermost location where the height of said air passage above said pool top is a minimum;
• as seen in a sectional view of said bowl Outlet taken normal to said centerline at said lowermost location, all but the top of said bowl outlet lies substantially coincident with an imaginary circle of a predetermined radius, with said air passage top wall forming an upwardly extending vent that projects above the top of said imaginary circle and with said vent having a height that is at least as great as its average width, and the distance between said pool top and the bottom of said vent is less than the height of said vent.

A vacuum assisted toilet which includes a toilet bowl, a bowl outlet that has upper and lower traps and a trapway between said traps, and a water source and a vacuum source that flows water into said bowl at the beginning of a flushing and that applies a vacuum to said trapway during a flushing, respectively, characterized by:

• said bowl outlet has a centerline and upper and lower walls at said lower trap, said lower wall forming a container to hold a pool of water that has a pool top, with said container having a downstream end lying at the same level as said pool top, and said upper wall forming an air passage that lies above said pool top, with said air passage having an air passage top wall with a lowermost location where the height of said upper wall above said pool top is a minimum;
• as seen in a sectional view of said bowl outlet taken normal to said centerline at said lowermost location, all but the top of said bowl outlet lies substantially coincident with an imaginary rectangle that has rounded corners, with said air passage top wall at said lowermost location extending above the top of said imaginary rectangle to form an upwardly extending vent in said upper wall that has a height that is at least as great as its average width, and the distance between said pool top and the bottom of said vent is less than the height of said vent.

A vacuum assisted toilet which includes a toilet bowl outlet to which a vacuum is applied, with said outlet having upper and lower traps and a trapway between them, wherein said lower trap has upper and lower trap walls and is formed to hold a pool of water with the downstream end of said lower trap wall defining the top of said pool, said upper trap wall forming an air passage above said top of said pool, with said air passage having a lowermost location along the length of said bowl outlet where the height of said air passage above said top of said pool is a minimum, wherein:

• said lower trap is formed so at said lowermost location said top wall has an upwardly projecting vent which forms at least part of said air passage and that vertically extending side walls wherein said vent has an average width that is less than one-half of the maximum width of said lower trap, and with said top of said pool lying closer to the bottom of said vent than the maximum height of said vent.