"Calvin Sambrook" wrote in message
...
"Stephen" wrote in message
...
On Wed, 2 Sep 2009 22:55:10 +0100, "Calvin Sambrook"
wrote:

That's almost certainly true but remember that this type of diverter
isn't
very good at collecting 100% of the rainfall anyway and the percentage
collected drops as the rainfall rate increases because it's only
collecting
from the wall of the downpipe

Is there a better type that collects nearer to 100% of the rainfall?


As I said in an earlier post I have one which collects all of the rainfall
but it's old and I can't find them on sale anymore. Essentially it forces
all of the rainfall into the butt and allows the butt to overflow back
into the downpipe at about 1/2 bore (ie. a semicircle of 68mm pipe). All
in one neat fitting.

I thought all rain went down the sides of the pipe. I didn't think any
went free fall down the middle?

During heavy rain there are two effects. One is that water will be
cascading down the pipe away from the ways anyway but the other is that
it's
^^^^
Obvoiusly that should read "walls"
falling from, say, 4m so has considerable velocity. Don't expect all of
it to be neatly caught by the internal lip and not bounce. Try fitting a
short length of pipe to the top of a normal diverter and pouring a jug of
water into it and see how much comes out of the side hole and how much out
of the outgoing downpipe.