Dear Ian,
When pumping with rods, a balance bob was always used at the shaft lip, to counterbalance the weight of the rods in the shaft. Basically, it was a see-saw with a tall post in the middle. The horizontal rod to the engine was attached to the top of the post, while the vertical rod was attached to one end of the see-saw which projected out over the shaft. The other end of the see-saw had a big crate of rocks, old scrap iron etc - basically a heavy weight, which was supposed to be the same weight as the rods in the shaft. If this was not done, the engine would not be powerful enough to lift the rods, let alone any water!
This method was standard on all mines which used bucket or plunger pumps, worked by water wheels or steam engines, and was common in south-west England in the 18th and 19th centuries. Strokes per minute depended on the power of the engine. With water power, maybe 4-5 stokes were possible, but some steam pumping engines were capable of as many as 13 in extreme circumstances. If you want to know more about this, I suggest you get a copy of 'The Cornish Beam Engine' by Dennis Bradford-Barton, published by David & Charles.
Hope this helps.
Robert Waterhouse
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Message Received: Oct 29 2006, 02:08 PM
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Subject: Pumping configuration query
Hello listers,
In the area where I currently work (Chillagoe, North Queensland) one of the old mines (Girofla) was notably wet and pumping was conducted in the 1920s by means of a vertical pump rod attached to a 'balance bob' which sat in line with a horizontally acting steam engine. I presume there was a connecting rod between the fly-wheel and the top of the 'balance bob'. Was this a common pumping arrangement at that time ? How many 'sweeps' per minute might the pump rod typically achieve with this configuration ? Any thoughts welcomed.
Regards
Ian Hodkinson
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