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

: One thought I had was using a rubber ball which is flexible enough to be
: calapsed with the foot but has plenty shape memory to draw water inside
: when released. I have seen these balls somewhere but I can't recall now
: where or what they were for. This is similar to some large volume air
: pumps which are used for inflating rafts and other water toys. I think the
: ones made for pumping air do not have adaquate strength to pump water,
: although I haven't tried it. Mounting the check valves should be
: relatively easy and maybe the ball could be held in position by mounting
: the valves to the bulkhead.

: Just a possible solution which would need more research and testing!

: Doug