|Feb 22, 2014, 11:38 PM|
Bernhard, I wonder if you'd get more water flow if you slowed the pump. I would suspect that internal cavitation is killing efficiency. Your slow speed test seemed to put out almost as much water as your high speed test, but I may be wrong. If you are getting cavitation, that will accelerate wear on the pump.
|Feb 23, 2014, 04:47 AM|
Bradford West Yorkshire, UK
Joined Apr 2010
Although it's questionable to use an oscillator as a water pump apart from merely moving water, back pressure from a boiler is likely to push the cylinder off its seat, it was/is widely used as a lubrication pump in model Locos via a lever and ratchet and pawl mechanism. ie. very slow operation.
|Feb 23, 2014, 02:25 PM|
Chedder water pump
I think that Brooks has hit on the head.
As the pump is driven by the engine when it's running on the bench the engine nor the pump are doing any work, the pump is only moving water and at the high revs it's drawing air some where until it's under load.
Once the boat is in the water and the engine slows down under load the revs will be much lower.
I notice on the video that when you put your finger over the discharge end the pressure builds up and the pump works better.
I had one of these pumps fitted in a Clyde puffer some years ago and must admit that I was not impressed with the pump when it arrived.
However I powered it by an electric motor at 120 r.p.m. and it worked perfectly against a boiler pressure of 35 p.s.i. at the time of building I had no machinery so I used Meccano pulleys and a large "O" ring. .
With a full tank of gas I could sail all afternoon for about 4 hrs using pond water and had no problems at all.
Hope this helps.
|Feb 24, 2014, 02:13 AM|
This was just a quick test
but after the pump This is fitted to the boiler, so it is very efficient operation from 0.30 to 35 psi no problem .. it provides almost .. too much water to be used as the bypass valve.
so it works ok ...
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