Manhole base

1. A manhole base or liner for directing the flow of liquid from a manhole inlet opening positioned in one of a plurality of possible locations in a manhole side wall to a manhole outlet opening in the manhole side wall, the base or liner comprising:

(a) a perimeter;

(b) an upper surface extending to the perimeter; and

(c) a liquid flow path formed in the upper surface and having, in series, first and second flow path portions, the first flow path portion defined by a first bottom wall and a pair of spaced apart side by side guide walls extending upwardly from the bottom wall, the guide walls each having a guide wall inner end and a guide wall outer end, the outer ends being located at the perimeter and being spaced apart a greater distance than the distance between the inner ends, the second flow path portion being defined by a second bottom wall, contiguous with the first bottom wall, and a pair of spaced apart side by side channel walls extending upwardly from the second bottom wall, each channel wall having an inner channel wall end and an outer channel wall end, the inner channel wall ends meeting the respective guide wall inner ends, and the outer channel wall ends being located at the perimeter.

2. The base or liner of claim 1 , wherein the guide walls are straight and tapered from the guide wall outer ends to the guide wall inner ends.

3. The base or liner of claim 2 , wherein the angle of one guide wall relative to the other guide wall is from 30° to 180°.

4. The base or liner of claim 3 wherein the angle of one guide wall relative to the other guide wall is less than 150°.

5. The base or liner of claim 4 wherein the angle of one guide wall relative to the other guide wall is less than 120°.

6. The base or liner of claim 5 wherein the angle of one guide wall relative to the other guide wall is less than 90°.

7. The base or liner of claim 6 wherein the angle of one guide wall relative to the other guide wall is less than 60°.

8. The base or liner of claim 1 wherein the angle of one guide wall relative to the other guide wall is greater than 90°.

9. The base or liner of claim 1 , wherein the guide walls are upright.

10. The base or liner of claim 1 , wherein the channel walls are upright.

11. The base or liner of claim 1 , wherein the channel walls are parallel to each other.

12. The manhole base of claim 1 , wherein the junctions between the first bottom wall and the guide walls are curved.

13. The manhole base of claim 1 , wherein the junctions between the second bottom wall and the channel walls are curved.

14. The manhole base of claim 1 , wherein the first bottom wall has an upper and outer peripheral portion and a lower and inner central portion contiguous with each of the upper and outer peripheral portion and the second bottom wall, the upper and outer peripheral portion extending downwardly towards the lower and inner central portion.

15. The manhole base of claim 1 , wherein the second bottom wall has a portion which is lower than the lowest portion of the first bottom wall.

16. A manhole comprising:

(d) a base or liner according to claim 1 ;

(e) a peripheral side wall rigidly coupled to the perimeter of the base and extending upwardly therefrom;

(f) at least one inlet opening formed in the peripheral side wall through which liquid can flow into the manhole, the inlet opening being positioned between the guide walls;

(g) an outlet opening formed in the peripheral side wall through which liquid can flow out of the manhole, the outlet opening being positioned between the channel walls;

whereby liquid flowing into the manhole through the inlet opening is guided along the liquid flow path and out through the outlet opening.

17. The manhole of claim 16 comprising a plurality of the inlet openings.