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G/A of sinking lifts showing telescopic suction pipe and method of suspending pumps
flink]Personal-Album-1228-Image-50546[linkphoto]Personal-Album-1228-Image-50546[/linkphoto][/link]
G/A Of plunger lifts showing position of rods for lowering sinking lifts.
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Plunger lifts showing method of continuing the pump rods under the first lift for the next lift, also the method of attaching the sinking lifts
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Cornish Pitwork showing the front & side elevations of pump work, rods & balance bobs for the whole depth of shaft.
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Details of Cornish bucket or sinking lift

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OK..... you just answered about 50 questions in one post... thanks ... IC 🙂 🙂 🙂

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Excellant information, much more interesting than the new-fangled submersible electric jobs.

Edit: Brings back memories of packing glands and greasy graphite packing on industrial Willet Pumps.

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There is quite a lot of information in these drawings.
They show two horizontal compound engines working pump rods, a man engine and a capstan.
they also give a good example of: flat rods, vertical rods,
rods on the underlie, balance bob, angle bob, and fend off bob.

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Nice bit of kit. 🙂

yep superb... :thumbsup:

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Looking at all these wonderful set-ups I guess the proportion of pump rod balance would depend on the type of pump/engine combination?

Any figures for different configurations?

That's a good point you've raised there. the weight of the rods apart from the bucket lift in the sump pumped the water, so the weight of the water in the rising main is a constant figure. A variation to the weight of the rods could occur in periods of wet weather which would make them heavier, so therefor more weight would have to be added to the boxes, to be removed again when they dried out.
To the west of Camborne was a mine named Wheal Johny. The practice was when a mine closed and the pit work was removed enough rods were left on the engine to keep the bob outdoors. When the rods dried out the engine would go indoors, until it rained again when it would resume its original position and local people would say , "wheal Johny's made another stroke.
These engines and boxes were finely tuned and even a small dog jumping onto a surface balance bob would upset them.

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That's a very interesting info about the apparent 'Ghost Pump'. 🙂

With a Hathorn Davey type engine with linked bell cranks (where each stroke was a power stroke), I suppose the entire weight of the rods could be balanced? The two rods already balancing each other when static.

The term power stroke is a little misleading and I will address that later. As with the H/D differential engine yes you are right the two rods balanced each other and by way of the differential gear only a whisp of steam was required to ease the rods over centre. The piston speed of these engines was only just over half of the Cornish Engine and is as follows:
Cornish Engine ( any type ) 500 feet per minute.
H/D differential type 220 feet per minute.
The pumping output was about the same owing to the use of two rods.

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There are several sets of pitwork still in situ in Cornwall.

Seeing the stuff in the metal poses the question "how on earth did they move it around?" The pump bodies aren't the sorts of things you can just lower down a shaft.

The pump bodies were indeed lowered underground by means of hand or steam capstans.
A steam capstan is still in situ at S. Crofty
🔗South-Crofty-Tin-Mine-User-Album-Image-027[linkphoto]South-Crofty-Tin-Mine-User-Album-Image-027[/linkphoto][/link]

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That's a very nice engine. 🙂 I'm intrigued by the missing inboard crank bearing, it does not look like it could be removed without lifting the crankshaft?

The term power stroke is a little misleading and I will address that later. As with the H/D differential engine yes you are right the two rods balanced each other and by way of the differential gear only a whisp of steam was required to ease the rods over centre. The piston speed of these engines was only just over half of the Cornish Engine and is as follows:
Cornish Engine ( any type ) 500 feet per minute.
H/D differential type 220 feet per minute.
The pumping output was about the same owing to the use of two rods.

Thanks for clarifying the the balance question with HD engines, the only other balance requirement would seem to hinge on shaft rod bearing loadings.

I can also see there could be confusion over what constitutes a 'Power' stroke as regards lift versus ram pumps.

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One thing that has crept in over the years is the erroneous descriptions of how this engine worked. Quite a few authors describe the engine as using a power stroke via the low pressure cylinder to pump the water, this is wrong! and the sequence is as follows:
As the drawing shows the engine at mid stroke we must assume that it is on the outdoor stroke i.e. with the bob C dipping to the shaft.
Steam is then admitted to the underneath of A the HP cylinder, at mid stroke the equilibrium Valve opens and the steam then passes to B at the top of the low pressure cylinder to complete the indoor stroke. This steam then passes to the condenser and the rods in the shaft descend under their own weight to pump the water. Then the cycle begins again.

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I've never seen that type of engine/pump in operation so the description settles a few questions. 🙂
Another question, would such an engine show any signs of the mid stroke steam tranfer, a slight pause or irregularity of motion?

Edit: I'm guessing that the inertia of the reciprocating masses smoothed this out a fair bit?

There would be no pause whatsoever

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There would be no pause whatsoever

Thanks. I forgot to ask, what would be the operating (HP inlet) steam pressure of the last built engines of this type?

I'm sorry I should have stated that, it was 150 Lbs PSI as opposed to 45/50 Lbs PSI on the coventional Cornish Engine

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I'm sorry I should have stated that, it was 150 Lbs PSI as opposed to 45/50 Lbs PSI on the coventional Cornish Engine

No problem, one of the downsides of internet communication, these things are much simpler across a pub table, or better still across a hot cylinder head.;D

The higher pressures involved would smooth any steam transfer lag between cylinders.