Post by Joe
On Sat, 30 Nov 2019 18:56:49 +0000
Post by Dan S. MacAbre Post by MM
I pumped up my first football ever by inserting the supplied needle
and using a pump. What I'd like to know is, what kind of valve is in
there to keep the air in once the needle is withdrawn?
As far as I remember, it was a bit of tubing that collapsed like a
flat balloon (but not so flimsy) once you'd taken the pipe out. You
can push the pipe in, and inflate; but once it's withdrawn, the tube
collapses, and the pressure keeps it flattened.
A little bit like a biscupid heart valve, I'd suggest.
These days it's likely to be a fairly solid tube with the hole bored
part of the way along, then a longitudinal cut for the rest of the way.
The needle pushes the cut halves apart.
When I was around 5, I recall having a rubber beachball like that - with
a 'valve' that was little more that a small slit in the side. The
wall/skin of the ball continued a little way in through the slit, and
when inflated, the internal pressure held the slit tightly closed. I
remember having to make sure that the slit was always totally free of
sand, otherwise it leaked.