On 11/02/2021 14:35, Andrew wrote:
On 11/02/2021 12:41, Steve Walker wrote:
On 11/02/2021 11:06, Jethro_uk wrote:
On Thu, 11 Feb 2021 10:56:39 +0000, Tim+ wrote:

Jethro_uk wrote:

I often wonder how efficient you can make a circular transport like
that.
Like lifts in buildings that should need hardly any energy if the
lift+load is never much more than lift+counterweight ....


Well, the Falkirk Wheel boat lift is reputed to use no more than an
electric kettle (3kW say) to lift a load of 500 tonnes.

It's on a very long list of things to see before I die ...

Pretty certain I read that Tower Bridge was operated with a gallon of
water or something similar ...

No. IIRC it is a 100 ton weight sitting on a column of water. The
water is pumped in by electric pump (used to be steam) and left there
until needed.

When the bridge needs opening, the bridge is lifted by hydraulic
motors, powered by the weight pushing the water. The column stores
enough to open the bridge twice.

A simple way to use low powered pumps to slowly store energy, that can
then be used rapidly when needed.

Tower bridge was operated by the high pressure water ring main that
opened/closed all the lock gates in docklands nearby.
It was also used to power all the big bed lifts are St Bartholomews
Hospital. When I worked there in the 1970's this supply was
shut down and the hospital had to spend over a million pounds (in 1970
money) to replace all these lifts.
Colt Telecom bought the redundant pipework and ran their fibre optic
cables inside them.

I don't think Tower Bridge has ever been connected to a ring main. It
was built with two steam engines to fill the accumulator. A third was
added during WW2. All three were replaced by electric pumps in the 1970s.