: Hi Doug, My thoughts exactly. How about half of a rubber basketball? A little
: "grip" for your feet, and a nice round shape. You could screw or
: band the perimeter of the "hemisphere" of basketball to a short
: length of 8" PVC pipe which would have the valves mounted in it. One
: of those SS hose clamps should work nicely for a band.

: If the ball lacked sufficient memory to draw water inside, you could mount a
: SS compression spring inside the pump to push the ball outward.

: Valve details are similar to those used in my hand pump design.

: Shawn

That would work reliably and be large volume. If a basket ball is 12 inches in diameter and half of it were used the volume would be about 450 cubic inches. That's about 9 times the volume (per stroke) of the hand pumps I've used!

I had in mind to make a mount similar to the one you have with one side concave to accept maybe 1/4th the ball (I figured about a 6 inch dia. ball), the whole ball could be used and glued in place with rubber cement. But that would require you to form the spherical shape into the mount which would be difficult. It would protude from the bulkhead maybe more than I would like. The volume per pump would only be about 110 cubic inches and it would be difficult to expel all the water from the ball.

Your solution is better I think!

We need to source a good quality thick walled rubber ball so no spring is needed and this pump could be made light weight, quickly and at low cost!

This bulletin board is great isn't it!?

Doug in Colorado.