Toilets with improved trapways

1. A toilet comprising:

a trapway extending between a bowl opening and a toilet outlet, the trapway extending from the bowl opening to a weir above the bowl opening, then to a down leg, then to a heel, then to an out leg;

wherein the heel links and provides a bend between the down leg and the out leg, the heel having a cross-sectional profile having a major dimension and a minor dimension, the major dimension increasing as the down leg transitions into the heel and also reducing as the heel transitions into the out leg, and the minor dimension reducing as the down leg transitions into the heel and increasing as the heel transitions into the out leg;

wherein the down leg has a cross-sectional profile that is essentially circular, and the trapway is capable of generating a siphon during a flushing action of the toilet;

wherein a portion of the down leg has a constant medial dimension and extends straight; and

wherein a portion of the out leg has a constant medial dimension and extends straight.

2. The toilet of claim 1 , wherein the reduction of the minor dimension as the down leg transitions into the heel focuses flow through the trapway at the heel to generate a hydraulic jump and thereby facilitate formation of a siphon in the trapway during a flushing action of the toilet.

3. The toilet of claim 2 , wherein the down leg and the out leg each have a major dimension of between 2 and 2.25 inches and a minor dimension of between 2 and 2.25 inches, and the heel has a major dimension of between 3.2 and 3.7 inches.

4. The toilet of claim 1 , wherein the out leg has a cross-sectional profile that is essentially D-shaped.

5. The toilet of claim 4 , wherein the heel has a side wall having an inner surface, and at least a portion of the inner surface of the side wall has a flat portion that transitions into a flat bottom of the out leg.

6. The toilet of claim 1 , wherein a maximum cross-sectional area of the heel exceeds a cross-sectional area of the down leg adjacent to the heel.

7. The toilet of claim 6 , wherein a maximum cross-sectional area of the heel exceeds a cross-sectional area of the down leg adjacent to the heel by at least 25 percent.

8. The toilet of claim 1 , wherein the down leg is essentially vertical from the weir to the heel and the out leg is essentially horizontal.

9. The toilet of claim 8 , wherein the out leg extends in a forward direction.

10. A toilet comprising:

a bowl including an opening; and

a trapway including an inner passage that includes an up leg, a down leg having a straight vertical portion, and an out leg having a straight horizontal portion, the trapway being configured to connect the bowl opening to a waste line;

wherein a transition between the down leg and the out leg includes an outer bend and an inner bend, the outer bend and the inner bend each extending from the down leg to the out leg;

wherein the outer bend includes a curved portion that is sharper than the inner bend;

wherein the transition between the down leg and the out leg has a cross-sectional area that is greater than a cross-sectional area of the down leg and is also greater than a cross-sectional area of the out leg;

wherein no portion of the outer bend between the down leg and the out leg is convex; and

wherein in the transition from the down leg to the out leg, the lateral dimension decreases then increases.

11. The toilet of claim 10 , wherein an angle between the down leg and the out leg is approximately 100 degrees.

12. The toilet of claim 10 , wherein the trapway has a medial dimension and a lateral dimension; and

wherein in the transition from the down leg to the out leg, the medial dimension increases then decreases.

13. The toilet of claim 10 , wherein the out leg transitions to the waste line at an outlet bend, and wherein the outlet bend is approximately 90 degrees.

14. The toilet according to claim 1 ,

wherein during a flush cycle, water in the down leg and in the out leg has a greater velocity than the water in the heel, the velocity of the water in the out leg being less than the velocity of the water in the down leg.

15. The toilet of claim 14 , wherein the trapway progresses from a substantially D-shaped cross section at the weir to a substantially circular cross section at the down leg and then back to a substantially D-shaped cross section at the out leg.

16. The toilet of claim 1 , wherein the heel includes an outer bend and an inner bend each of which extend from the down leg to the out leg, the outer bend includes a curved portion that is sharper than the inner bend, and no portion of the outer bend between the down leg and the out leg is convex.

17. The toilet of claim 16 , wherein the heel has a cross-sectional area that is greater than a cross-sectional area of the down leg and that is also greater than a cross-sectional area of the out leg.

18. The toilet of claim 17 , wherein during a flush cycle, water in the down leg and in the out leg has a greater velocity than the water in the heel, the velocity of the water in the out leg being less than the velocity of the water in the down leg.

19. The toilet of claim 10 , wherein the outer bend of the transition includes a straight portion that is positioned above and connects to the curved portion.