Fig 1 MacAdam-Fourneyron turbine
Fig 2 Cross Secion through Turbine
[Frm Bulletin Peak District Mines Historical Society. Vol.6, No.2. pp 85-92, October 1975 ]
by A.M. Gillings
The Isle of Man is highly mineralised, with rich deposits of lead and zinc, and lesser quantities of copper and iron ores, but the Island is devoid of coal or other fuel supplies, In order to work the mineral resources, the early miners were forced to find other sources of energy.
The Island rises steeply out of the Irish Sea, and has an annual rainfall of 55 inches, resulting in well-filled streams in the numerous deep glens around the Island. The miners harnessed these streams to provide their power, often using the same stream to power several wheels in succession. Most of these were of the vertical type, as in a conventional farm mill. However, in the Laxey and Glen Mooar area alone, there were at least five horizontal wheels, or what we would now call 'turbines'. In the same valley there were also two water balance engines and a water-pressure (piston) engine.
Three turbines can still be identified in Glen Mooar, and these were a variation of the Fourneyron type. Irish millwrights were well versed in the use of water-power and the MacAdam brothers, of the Soho Foundry, Belfast, first manufactured their version of the Fourneyron turbine in 1850. They probably supplied the Great Laxey Mining Company with the Glen Mooar turbines, although no definite records have been found.
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Fig 1 MacAdam-Fourneyron turbine |
Fig 2 Cross Secion through Turbine |
The principle of the MacAdam-Fourneyron turbine is shown in figs. 1 and 2. In fig. 1 water enters a cistern under pressure via the cast iron pipe 5, and flows as shown by the arrows up the central control cone 3, and out through the stator guide vanes 1 and rotor buckets 2. Fig. 2 shows a cross-section through these blades. Water flows outwards through the stator and is directed by the guide vanes so as to strike the rotor buckets as near to a tangent as possible. The resultant reaction of the buckets turns the rotor clockwise, and the water continues travelling outwards to be thrown off by the tips of the turbine blades. The blades are shaped so that for maximum efficiency, the water actually travels in a radial line through the rotor.
The control cone 3 can be raised and lowered within the stator housing by a system of levers in the cistern, not shown in the drawing. When fully raised, all the guide vanes are covered, preventing any water flowing. By gradually lowering the cone, progressively larger quantities of water can be admitted to the buckets, and the turbine will begin to gather speed.
It has been found through experience that a completely filled small bucket is more efficient than a larger bucket only partially filled. For this reason the guide vanes and buckets are divided by a number of horizontal plates. The control cone can thus be adjusted so that only the top row of Vanes are uncovered, the top row of buckets being completely filled, and the lower rows being completely empty. In the turbine shown there are three positions of maximum efficiency, although there is nothing to prevent the cone taking up a midway position.
The waste water was not guided in any way after leaving the turbine, but the latter was usually submerged in water, at least to cover the turbine blades, although turbines working under a 9 ft. depth of tail water have been recorded.
The turbine would normally be situated in the lower part of the mill or machine-house, and the output shaft (point 4 in fig. 1) would reach up to the machine floor, where bevel gears would connect it to horizontal shafts. The vertical shaft was secured to the rotor by a key-and-keyway at point 6, (fig. 1), and in the example shown, the vertical thrust due to the weight ot the shaft was taken on a cast iron and brass bush, item 7.
The most complete turbine remaining in Glen Mooar, the subject of recent investigations, was installed in the 1860s. It was used to drive an air compressor for powering rock drills when sinking the Dumbell's Shaft of the Great Laxey Mine, and later for compressed air machinery in the mine itself. The turbine is listed in the British Watermill Survey as plant number 24/008.1.
The compressor house spans a very narrow part of Glen Mooar and is accessible via an overgrown cart-track from near the village of Agneash. The turbine is built into the basement, from where the tail water joined the Mooar Water which flows through a large archway under the building. Access to the turbine itself today is best obtained by climbing down into the stream upstream of the turbine house and wading through the tunnel under the house. Water was collected from the upper reaches of the Mooar into a cistern on the hillside about 100 ft. above the turbine. (Such cisterns are not part of the turbine mechanism, but stone-built tanks 10 feet square and deep, wherein water was collected from leats etc.) A 20-inch diameter pipe brought the water to the turbine. Just before entering the turbine house, an eight inch branch pipe led off downstream to feed the Main Engine in the Welch Shaft. This Main Engine caused considerable problems with water-hammer, and four blow-off valves were fitted around the turbine to prevent damage.
Fig. 3 shows an elevation of the turbine. At point 1 is the stator, the guide vanes being obscured by the rotor, 2. Water enters via pipe 5, and the mechanical output taken from shaft 4. Rod 9 is the control rod, which was raised and lowered by a screwed handwheel at the machinery floor level to raise and lower the internal control cone. Above the rotor blades are a series of small holes, and one larger one. The former allow excess water to drain away from the bearing, (there is bound to be some leakage upwards from between the rotor and stator) whilst the large hole allows the bearing to examined.
Two blow-off valves were fitted directly to the cistern, shown in the inset sketch. within the body of the valve 12 a plunger covered the end of the vertical pipe, This was held down by the weighted lever, until the water pressure overcame that of the weights, when the plunger would lift off its seat and allow excess water TO escape through the outlet. 13. The weights, 14, are of interest They are made up of conventional cheese weights, (i.e . flat discs of iron that can be added to or removed from the pile at will) but the lowest platform was a scrap bevel gear, suggesting that the assembly had been made in the mine's own workshops, One valve was fitted to the cistern at point A; the other was fitted on the opposite side
At the inlet to the cistern a large stand-pipe was clamped to the inlet pipe, and this terminated in another blow-off valve. The exact operation of this is not clear, but it would appear that the weight 14a moved in the vertical quides, and presumably pressed on a plunger concealed within the casting, 10. A fourth blow-off valve, 11, similar to those on the cistern, was fitted to the side of the standpipe.
All the compressor equipment has been removed, with the exception of the air receiver outside the building (shown in Jespersen, (1970, fig. 64). The machine beds for two compressor cylinders can be identified in the corner of the building nearest the turbine. The same building also contained a steam-powered stand-by compressor, with a lean-to boiler house at one side.
The house for the most northerly turbine of the Laxey Mines, (plant no 24/005) still stands just below the Ballacregga Reservoir, although the reservoir was not connected with this turbine. The machinery has been removed, but probably drove a compressor for sinking the North Shaft. This shaft was abandoned and filled in before it reached the Adit Level of the mine.
Plant no 24/006 was originally a vertical water-wheel for winding in the Dumbell's Slide Shaft. When the main Dumbell's Shaft was sunk, it was necessary to use a more efficient engine, (i.e. a turbine) but even this proved inadequate, and a second turbine, 24/009, was built. There is no machinery left at either location, and both engine houses are virtually ruined.
The fifth turbine in Glen Mooar, 24/011, was used for tandem winding in the Engine and Welch Shafts. It was built in 1862 to replace the steam powered beam engine of 1846 to economise on fuel, although the steam engine was retained as a standby for many years. The supply cistern, turbine cistern, and control cone still remain, although the stator and rotor have been removed. As with all other plants, the turbine was situated in the basement of the building, and the output shaft extended upwards to the winding-drum floor. The gear train included one pinion with wooden teeth: if the winding rope got caught, these teeth would shear off and save the turbine from damage.
The Man Engine was installed in the Welch Shaft in 1881 for raising and lowering men between the Adit and the working levels of the Great Laxey Mine. The machinery was installed about 40 feet below the surface, i.e. about 140 feet above Adit, and is inclined at 15° from the vertical to be in line with the shaft. The principle of the engine for raising men was weil known, Cornish tin miners having used the pump rods for this purpose. The Laxey Engine is unusual in the way in which the up-and-down motion is created.
The principle of operation is shown in figure 4, which is based on a sketch drawn several years ago by Mr. Nelson Kewley, who worked in the mines for many years. The main cylinder, 1, was 24 inches diameter, with a stroke of 12 feet. Two smaller cylinders, 3 and 5, were 10 inches diameter, 15 inches stroke, whilst the third cylinder, 8, acted as a slide valve, with 4% inches pistons. The output from the main piston was coupled to the shaft rods by a cross-head below the engine. The slide valve was also connected to the cross-head by an adjustable linkage which introduced a certain amount of 'lost motion'. The main water supply was taken from the feed pipe to the Dumbell's Compressor Turbine via an 8-inch pipe to the top of the Welch Shaft, and then down the shaft to the stop valve 12. The pressure here was recorded on one occasion as 92 p.s.i., corresponding to almost 200 feet head of water. This would produce a theoretical maximum lift of 18 tons on the main piston. A separate auxiliary water supply from the shaft-top fed the slide valve cylinder.
In the position shown, when stop valve 12 is opened the main piston will rise due to the pressure of water on the underside of the piston. As it approaches the upper position, the slide valve rod, 11, is pushed up by the cross-head, so that ports b and c are connected, as are d and e. The auxiliary supply now flows under piston 4, raising the rod with piston 6 and cut-off valve 7. The latter now lies between ports P and Q, shutting off the inlet, and connecting the main cylinder to the outlet port R. The main piston, 2, falls under the weight of the shaft rods, until at the bottom of the stroke, the cross-head and connecting link pull the slide valve down to regain the position shown. Pistons 4 and 6 are driven downwards, and the cut-off valve 7 re-admits water under pressure to the main cylinder.
Item 13 was a length of ships' hawser coiled in the bottom of the main cylinder to cushion the shock whenever the piston dropped right to the bottom. In practice, it created more problems than it cured, getting uncoiled and blocking the water inlet/outlet. It was later removed and its duties performed,by catch pieces on the shaft rods. The cut-off valve had a number of holes at each end so that the supply was cut off gradually but even with this water-hammer occured with every stroke, reverberating back through the main with devastating effect. When the engine was first installed, the water-hammer was sufficient to blow the complete stator casing and rotor off the Compressor Turbine, It was for this reason that the four blow-off valves were fitted. to the turbine and two more to the eight-inch supply pipe. It appears that these measures were not entirely successful and water blew off at all the valves on every stroke.
The stroke of the main piston was adjusted by left and right handed nuts on the connecting rod 11, altering the point at which the slide valve operated.
The shaft rod was wooden 10 inches by 7 inches, joined at intervals by iron strapping plates. Every twelve feet a small platform 20 inches square, was fitted and corresponding landings were fixed in the shaft also at twelve foor itervals. To climb the shaft, the miner would wait until the engine had reached the bottom of its stroke when the platform and landings would be in line with each other. He then stepped onto the first moving platform and rose with the rod to the next landing, where he would step off smartly and the rods would start descending again When the next platform came down level with his landing, the miner would step on and rise another 12 feet on the next stroke. He would repeat this every stroke until he reached the Adit. Descending was done in a similar fashion, and with care, men could pass each other at the landings and travel in both directions. The Engine performed three or four strokes per minutes, and could raise a man from the lowest level to Adit(200 fathoms or 1200 ft.) in 25 minutes \u2014 preferable to climbing ladders! The miners would never normally see the Engine, and many of them were convinced that the shift rods were moved by a wheel and crank. the Engine,
The Engine and rods were inclined to suit the angle of the shaft. Rollers were fitted to the shaft wall at 18-20 ft intervals with the corresponding rubbing plates on the underside of the rods to take their weight. The weight of the rods was approximately balanced by three counterweight bob lever. The largest of these was an inverted T-shaped rocker 48 ft. long and 24 ft to the top ofv the leg. The whole assembly was pivoted at the junction of the two arms and the leg; one arm was connected to the shaft rods, whilst the other end was equipped with a large box which could be loaded with up to ten tons of ballast. Stays were stretched from the top of the leg to the end of each arm to strengthen the structure, which was all inclined at 15 to the vertical to take account of the hade ot the shaft. Rollers and rubbing plates were again provided to support the weight of the rocker.
The exhaust water from the engine was led into a small adit which reached the surface in the basement of the turbine winder house. It joined the tail water from the turbine and then went on to the cistern for supplying the Lady Isabella, and the adit also served as an access way for servicing the Engine. The adit in the basement of the turbine house is still accessible, and it is an easy walk in to the shaft with the Man Engine S water-pressure cylinder Ow supported (7) on wedged fallen blocks. The main stop valve is clearly visible but other parts are in various stages of collapse.
Laxey is famous for its Great Wheel, the Lady Isabella, now a tourist attraction and featuring prominently in advertising material for the Island. However, very few tourists appreciate its original purpose. It was built in 1854 to drain the Great Laxey Mine, and was named after Lady Isabella Hope, who. as wife of the Governor of the Island, performed the Opening ceremony. The wheel is 72 feet diameter, and of the pitch-backshot type. Water is collected in a cistern on the nearby hillside, carried by an underground pipe to the base of the wheel, then up the tower behind the wheel and across the top platform to the top of the wheel. It then doubles back on itself to run into the buckets on the side of the wheel nearest the tower. The wheel was claimed to be capable of pumping 240 gallons of water per minute from a depth of 250 fathoms, but the physical size of the plunger pumps and the speed of the wheel would have limited the Output to about 43 gallons per minute, a workload of 40HP. It was probably capable of much higher horsepowers, and it is probably due to this light loading that it has remained in such good condition. The wheel was situated 200 yards from the Engine Shaft, which contained the pumps, and the motion was transmitted by a horizontal beam running back and forth on two-wheeled bogies running on rails on top of a stone viaduct, and worked by a massive crank on the side of the wheel. Visitors often confuse this viaduct with the water supply for the wheel, which was in fact carried underground.
This was an inclined railway built in 1890 to take visitors up to the Great Wheel. Two counter- balanced carriages ran on adjacent tracks, coupled together by a rope which ran around a pulley at the top. A tank on the upper carriage was filled with water until it overcame the weight of the lower carriage and passengers, and started to run down the incline. At the bottom the water was drained off, and the other carriage, now at the top, would be filled for the return journey. The upper terminus formed part of the 'Wheel Cafe' building, whilst the lower terminus was by the bridge opposite the 'Manx Engineers' works at the bottom of the car park. The tramway was dismantled before the first World War, and only the cafe remains A similar tramway is still used during the season at the Falcon Cliff Hotel, Douglas.
The Hamaan lift was situated by the Ramsey Road where it crosses the Laxey Valley. It raised wagons of spoil from the washing floors (now laid out as pleasure gardens) to the tips on the north of the road. It worked on the same principle as the Browside Tramway, except that the tracks were vertical instead of being inclined. It was scrapped with the rest of the washing equipment, and subsequent building and landscaping in the valley has eradicated all traces of its existence.
Turbines run at a much higher speed and therefore tend to require less gearing between the prime mover and the machinery being driven - hence less friction. All the 'buckets' in a turbine are filled and are producing effort all the time, whilst a vertical wheel can be seen to 'lurch' every time a fresh bucket comes into the stream. Thus a turbine has a much more uniform output with less vibration. Also, there is a size economy, since in a vertical wheel, at least half the buckets are empty at any given moment and are simply so much dead weight. Turbines use a very high head but small quantity of water (hundreds of feet of head) whilst the useful head of a vertical wheel is governed by the diameter of the wheel (eg a maximum useful head of Lady Isabella is 72 feet, other water wheels much less). A certain amount of head must also be lost on a conventional wheel to allow the buckets to empty at the bottom of the wheel. A turbine can work with the wheel completely submerged, or (depending on design) with a tail-pipe producing a suction at the turbine output
Cullen (1871) quotes efficiencies: Turbines 75 - 85%, Vertical wheels 30 - 35% (3-4 ft drops) . 50-60% (6-8ft drops) Even if the efficiency of vertical wheels increased with more height, the physical size of the wheel increases out of all proportion to a turbine of corresponding horse power.
Cullen described how, after Visiting M. Fourneyron French hydraulics engineers, he designed a turbine (similar to those found on the Isle of Man) and had this made by the MacAdam Brothers. MacAdam's subsequently made a number of turbines on the same system. The I.0.M. has as much affinity for Ireland as for England, being roughly equidistant between the two. The Irish also had a problem of lack of indigenous fuel, and so the Manx would naturally turn to them for advice on alternative power sources.
The use of coal was not unknown on the Island and there are three instances
of steam engines as standby to water engines, viz:
i) Dumbell's compressor turbine
ii)— Engine/Welch shaft winder
iii) Washing floors. (Power supplied by a vertical wheel when water available,
two steam engines used in drought conditions.)
The Manx lead and zinc miners exercised considerable ingenuity in harnessing water power to save precious imported fuel. Many of the machines they built have been destroyed or scrapped, although the Lady Isabella has been carefully preserved and restored.
Whilst the MacAdam-Fourneyron turbines cannot be claimed as unique, they are not as common as 'Francis' and vortex turbines, and with this in mind, the Dumbell's Compressor Turbine would make an excellent subject for preservation. Again, the Man Engine is rare, if not unique, although its sheer weight and size (15 feet tall) would make its removal from the shaft for preservation very awkward.
Unfortunately, the limited resources available on the Island make preservation unlikely, even if a properly conceived 'interpretive centre' were established in the mining valley of Glen Mooar, it would form an ideal attraction for visitors to the Island. !
Grid references are given for various locations mentioned in the paper, and can be mostly be identified on the Ordnance Survey 1' map, sheet 87, or 1:50,000, sheet 95. Larger Scale maps at 6" to the mile (sheets SC49NW and SC48SW) and 25 inches to the mile are obtainable from the Government Offices
| North Shaft Turbine house | 24/005 | SC 44298650 |
| Dumbell's Winder | 24/006 | SC 43278601 |
| Dumbell's Winder | 24/009 | SC 43228600 |
| Dumbell's Shaft - | SC 43198603 | |
| Supply cistern for compressor turbine | SC 43298570 | |
| Dumbell's Compressor Turbine | 24/008.1 | SC 43208567 |
| Welch Shaft and Man Engine | 24/008.2 | SC 43248556 |
| Turbine winder | 24/011 | SC 43738548 |
| Engine Shaft | SC 43248541 | |
| Lady Isabella | 24/012 | SC 43218522 |
| Browside Tramway | SC 43218512 | |
| Hamaan Lift | SC 43288471 |
Dates of Water Powered Engines
| Plant No | Name/Duty | Installed | Disused | Present Condition |
| 24/005 | North Shaft Compressor(?) | 1919 | Machinery removed house still stands | |
| 24/006 | Dumbell's Shaft Winder Turbine | Doubtful traces | ||
| 24/009 | Dumbell's Shaft Winder Turbine | 1892 | No Machinery left house ruined | |
| 24/008.1 | Dumbell's Compressor Turbine | 1860 | 1919? | Turbine intact, house ruined |
| 24/008 2 | Man Engine | 1881 | 1919 | Still exists in situ in Welch Shaft |
| 24/011 | Engine/Welch Shafts Turbine Winder | 1862 | 1919 ? | A few parts remain in ruined |
| 24/012 | Lady Isabella | 1854 | 1929 | Restored and working pump, rods not connected |
| Browside Tramway | 1890 | 1914 | Upper terminus now part of 'Wheel Cafe': no other | |
| Hamaan Lift | 1929 ? | Sold for scrap in 1935 |
Cowin F. 1973 'Laxey Mines Trail'. Manx Conservation Council
Cullen W. 1871 'A Practical Treatise on the Construction of Horizontal and Vertical Waterwheels'. E& F.N. Spon
Garrard, L.S. et al. 1972 'Industrial Archaeology of the Isle of Man'. David and Charles. Newton Abbot. Jepersen A. 1970 'The Lady Isabella Water-wheel'. Society Danske Mollers Venner, 3rd Edition
Wilson, P_N. : 1957-9. 'Early Water Turbines in the United Kingdom'. Trans. Newcomen Society, Vol. XXXI, pp.219-241.
Fig 3 80 H.P. Turbine for Air Compressor
Fig 4
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Any comments, errors or omissions gratefully received
The Editor |
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