31 December 2017

Gough's Orchard Syphon update

Following the joint potting activity yesterday, the time came to run up the system and see how much improvement had been achieved.

With recent snow and rains, the mill pond outlet weir was running at full tilt with the level as high as it has been for a very long time.

It took 30 minutes to achieve syphon action.  Once flowing, the key measurement of success was the duty cycle measurement of vacuum pump on time to off time.  In the past it has been, at best, about 4:1.  Today it was nominally 10:1.  Some air was still getting into the system, but exactly where requires some investigation as aural evidence suggests that it is in the section that should be submerged!  We have not run out of potting supplies, so those joints low down could also receive supplementary sealant.

Our key indicator as to the air in the system is visible in the top float switch section which can be seen operating in the above video.

The syphon was run for about 90 minutes before switching off the pump and venting the pipes to stop it.  There is plenty of water heading down to Bowbridge at present.

Good progress, but a bit more to do....