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49-466: East Dundry is a south-facing hamlet some 160 metres above sea level in a sheltered valley of Dundry Hill just south of Bristol , England. The hamlet is in the parish of Dundry and about two kilometres east of its village church. The iron-age Maes Knoll tump (2.5 kilometres to the east) and tumuli (in the field just north-east of North Hill Farm) are evidence of long occupation of the valley. East Dundry's northern slope facing Bristol has supposedly

98-457: A 2-to-1 supply-head-to-delivery-head ratio and 70% efficiency, the delivered water would be 70% of 50%, i.e. 35%. Very high ratios of delivery to supply head usually result in lowered energy efficiency. Suppliers of rams often provide tables giving expected volume ratios based on actual tests. Since both efficiency and reliable cycling depend on water hammer effects, the drive pipe design is important. It should be between 3 and 7 times longer than

147-488: A British patent on his behalf in 1797. The sons of Montgolfier obtained a British patent for an improved version in 1816, and this was acquired, together with Whitehurst's design, in 1820 by Josiah Easton , a Somerset -born engineer who had just moved to London. Easton's firm, inherited by his son James (1796–1871), grew during the nineteenth century to become one of the more important engineering manufacturers in England, with

196-406: A continuation westwards from Maes Knoll of the remains of Wansdyke , a series some 31 km-long of early medieval defensive linear earthworks consisting of a ditch and a running embankment from the ditch spoil, with the ditching facing north, to repel invasion from the north. There are ancient downhill strip lynchets in the large field opposite North Hill Cottage; and mildly sloping ones in

245-447: A large scale version named the "Venturo Pump" is also being manufactured. A traditional hydraulic ram has only two moving parts, a spring or weight loaded "waste" valve sometimes known as the "clack" valve and a "delivery" check valve , making it cheap to build, easy to maintain, and very reliable. Priestly's Hydraulic Ram , described in detail in the 1947 Encyclopedia Britannica , has no moving parts. A simplified hydraulic ram

294-409: A large spiral is allowed, but elbows are to be avoided. PVC will work in some installations, but steel pipe is preferred, although much more expensive. If valves are used they should be a free flow type such as a ball valve or gate valve . The delivery pipe is much less critical since the pressure vessel prevents water hammer effects from traveling up it. Its overall design would be determined by

343-460: A large works at Erith , Kent . They specialised in water supply and sewerage systems worldwide, as well as land drainage projects. Eastons had a good business supplying rams for water supply purposes to large country houses , farms, and village communities. Some of their installations still survived as of 2004, one such example being at the hamlet of Toller Whelme , in Dorset . Until about 1958 when

392-469: A narrower metal pipe (crossing the stream and then all under the soil) up and through Nuthill field to North Hill Farm – much higher than the Upton Farm spring. The ram near the stream below Walnut Farm pumped water up to the farm. Upton farm also had (has?) a hidden, disused hydraulic ram near the same spring. Day and night, the rams thumped every 20 seconds or so and were audible throughout East Dundry until

441-443: A reliable supply. Nearly all old East Dundry have wells. The farmhouses North Hill Farm and Walnut Farm were built in the late 19th century on the hamlet's higher and flatter land – more suitable than the steeper land of the original farms, such as Spring Farm and the farm that was at the current North Hill Cottage with its large flattish walled-garden that was its farm yard. These two higher farms installed separate hydraulic rams in

490-620: Is Aid Foundation International in the Philippines , who won an Ashden Award for their work developing ram pumps that could be easily maintained for use in remote villages. The hydraulic ram principle has been used in some proposals for exploiting wave power , one of which was discussed as long ago as 1931 by Hanns Günther in his book In hundert Jahren . Some later ram designs in the UK called compound rams were designed to pump treated water using an untreated drive water source, which overcomes some of

539-530: Is direct evidence for movements of the Mendip Axis in Middle Jurassic times, making this an outstanding site for its bearing on studies of palaeogeography . 51°23′51″N 2°38′38″W  /  51.39756°N 2.64391°W  / 51.39756; -2.64391 Hydraulic ram In 1772, John Whitehurst of Cheshire , England , invented a manually controlled precursor of the hydraulic ram called

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588-410: Is falling downhill from the source, the flow slows; when the flow reverses, the delivery check valve [5] closes. Meanwhile, the water hammer from the closing of the waste valve also produces a pressure pulse which propagates back up the inlet pipe to the source where it converts to a suction pulse that propagates back down the inlet pipe. This suction pulse, with the weight or spring on the valve, pulls

637-515: Is immediately south of Bristol , England : it includes farmland, a small number of houses and a church. It stretches east–west for some two miles. Most of the hill is within the district of North Somerset . At the hill's eastern end the southern slopes are within Bath and North East Somerset , and the northern slopes are within the city and county of Bristol , including the highest point in that county. The village of Dundry , with its prominent church,

686-630: Is near the summit. At the eastern end is Maes Knoll , near Norton Malreward , an Iron Age hillfort and the start of Wansdyke . To the South lies the Chew Valley . On the western side of the hill is a spring which becomes the Land Yeo . Dundry Main Road South Quarry is a 0.7 hectare geological Site of Special Scientific Interest near the village of East Dundry , because of the number of fossils in

735-479: Is shown in Figure ;2. Initially, the waste valve [4] is open (i.e. lowered) because of its own weight, and the delivery valve [5] is closed under the pressure caused by the water column from the outlet [3]. The water in the inlet pipe [1] starts to flow under the force of gravity and picks up speed and kinetic energy until the increasing drag force lifts the waste valve's weight and closes it. The momentum of

784-404: Is that the pressurized air will gradually dissolve into the water until none remains. One solution to this problem is to have the air separated from the water by an elastic diaphragm (similar to an expansion tank ); however, this solution can be problematic in developing countries where replacements are difficult to procure. Another solution is a snifting valve installed close to the drive side of

833-516: The smithy , all strategically in Cold Harbour on the Bristol-Wells stage-coach mail road. Later the post office was some 200 metres north west of Dundry church in a house on the north side of the road. A week or so before war was declared, several London children were evacuated to East Dundry: for instance two were billeted to Spring Farm, two to The Dingle and some to The Rookery . Later in

882-636: The "pulsation engine" and installed the first one at Oulton, Cheshire to raise water to a height of 4.9 metres (16 ft). In 1783, he installed another in Ireland . He did not patent it, and details are obscure, but it is known to have had an air vessel. The first self-acting ram pump was invented by the Frenchman Joseph Michel Montgolfier (best known as a co-inventor of the hot air balloon ) in 1796 for raising water in his paper mill at Voiron . His friend Matthew Boulton took out

931-475: The 1920s was the first to be tarred into the hamlet. Bristol, with its centre only 6 kilometres away, had mains water, electricity, gas, and dial telephones by the 1930s – but the Second World War and its ten years of ensuing austerity stopped all extension of these facilities to places such as East Dundry. From 1923 until the 1950s there was a frequent Dundry Pioneer bus service from its Dundry terminus on

980-423: The 1950s, two until the 1920s, all mostly supplying milk to Bristol. Most buildings are built from the oolitic limestone quarried locally, probably mostly by the sites of the houses. Two large outcrops of Dundry stone are visible at Spring Farm. Until 1930, the inhabitants were almost entirely farmers and farm workers: gradually since then the hamlet has become a dormitory village for Bristol. East Dundry Lane in

1029-433: The 1950s. Walnut Farm ran their ram well into the mid sixties with the ram feed water supply coming from an open-topped limestone cistern built into the south side of the valley containing approximately 12 cubic metres of water bubbling up from an underground spring. The ram was housed in a small shed 40 metres into the base of the valley next to the stream with the waste wash from the ram flowing into it. The delivery pipe from

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1078-433: The allowable pressure drop based on the expected flow. Typically the pipe size will be about half that of the supply pipe, but for very long runs a larger size may be indicated. PVC pipe and any necessary valves are not a problem. A ram newly placed into operation or which has stopped cycling should start automatically if the waste valve weight or spring pressure is adjusted correctly, but it can be restarted as follows: If

1127-418: The delivery pipe. If opened too quickly it will stop the cycle. Once the delivery pipe is full the valve can be left open. Failure to deliver sufficient water may be due to improper adjustment of the waste valve, having too little air in the pressure vessel, or simply attempting to raise the water higher than the level of which the ram is capable. The ram may be damaged by freezing in winter, or loss of air in

1176-416: The delivery valve. This automatically inhales a small amount of air each time the delivery valve shuts and the partial vacuum develops. Another solution is to insert an inner tube of a car or bicycle tire into the pressure vessel with some air in it and the valve closed. This tube is in effect the same as the diaphragm, but it is implemented with more widely available materials. The air in the tube cushions

1225-627: The flat part of the Bristol-Wells road near the chapel at the top of Broad Oak Hill, into the then open-air bus terminus in Prince Street in Bristol via Dundry village, the Hairpin Bend, Bishopsworth, and Bedminster. Until the 1960s, letters were delivered on bicycles to East Dundry and all Dundry premises. The Dundry Post Office was a few houses south of the Carpenter's Arms pub and its north-side neighbour

1274-602: The hamlet, changing later to 63xxxx and yet later 963xxxx. Subscriber Trunk Dialling became available on 5 December 1958 to call a few UK cities. Bristol had the dialling code 0BR2 progressively changing to 0272 (the same on the dial as 0BR2), and then 0117 plus 7-digit Bristol numbers. During the lead-up to Christmas 1962 there were light falls of snow. Around Christmas Eve, after a slight thaw, freezing started again with significant snowfalls during Boxing Day, later to be known as ‘The Big Freeze of 1963’ . The previously partially-melted light and fluffy snow formed dense solid ice on

1323-546: The hamlet. Negotiations with the Electricity Board started with a meeting in Walnut Farm in 1952, with the installation in 1953 of an 11kV supply from across the valley. The houses and farms built before about 1890 (and dating back to mediaeval and earlier times) are all geologically close to the division between clay and the higher layer of Dundry hill's oolitic limestone – this allowed wells to be sunk for them, with

1372-507: The inferior oolite. The Main Road Quarry exposes a fine section in the Middle and Upper Inferior Oolite, with the rocks lying stratigraphically below them visible at Barns Batch Spinney . The former characterised by a typically southern English-Normandy fauna, including the rich ammonite occurrences of the "Brown iron-shot", and the latter by contrasting faunas of Cotswold aspect. This contrast

1421-406: The late 1800s and were served by them until the late 1950s. The farms needed ample water for their dairy herds prosperously supplying milk to Bristol by horse and cart. North Hill Farm laid a 6-inch diameter, china-clay pipe (still visible in places in the steep nearby stream) from the spring below Upton Farm to a ram in a small stone hut on the south side of the valley-bottom stream. There remains

1470-437: The mains water arrived, the hamlet of East Dundry just south of Bristol had three working rams – their noisy "thump" every minute or so resonated through the valley night and day: these rams served farms that needed much water for their dairy herds. The firm closed in 1909, but the ram business was continued by James R. Easton . In 1929, it was acquired by Green & Carter of Winchester , Hampshire , who were engaged in

1519-539: The manufacturing and installation of Vulcan and Vacher Rams. The first US patent was issued to Joseph Cerneau (or Curneau) and Stephen (Étienne) S. Hallet (1755-1825) in 1809. US interest in hydraulic rams picked up around 1840, as further patents were issued and domestic companies started offering rams for sale. Toward the end of the 19th century, interest waned as electricity and electric pumps became widely available. Priestly's Hydraulic Ram , built in 1890 in Idaho,

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1568-409: The pressure vessel leading to excess stress on the ram parts. These failures will require welding or other repair methods and perhaps parts replacement. It is not uncommon for an operating ram to require occasional restarts. The cycling may stop due to poor adjustment of the waste valve, or insufficient water flow at the source. Air can enter if the supply water level is not at least a few inches above

1617-407: The problems of having drinking water sourced from an open stream. In 1996 English engineer Frederick Philip Selwyn patented a more compact hydraulic ram pump where the waste valve used the venturi effect and was arranged concentrically around the input pipe. Initially patented as a fluid pressure amplifier due to its different design, it is currently sold as the "Papa Pump". Additionally to this

1666-424: The ram ran north up to a holding tank at the farm. Once a mains water supply was installed (1957/8) the water from the ram was used solely for livestock and washing down the yards. The rhythmic thumping of the ram had a shorter frequency than the one mentioned at North Hill Farm with gentle knocks about every 3 to 4 seconds. Water (pumped up Dundry hill from the small pumping station half-way up Broad Oak Hill road)

1715-432: The road past Spring Farm and up the track towards Rattledown Farm. In a few years every joint of this relatively high-pressure-gas steel pipeline had to be resealed when the supply was converted from town to natural gas. Later the pipeline was reduced in pressure to minimise gas losses and only served East Dundry. East Dundry telephone subscribers were originally served by a network of poles and overhead open-wire cables all

1764-413: The shock of the water the same as the air in other configurations does. A typical energy efficiency is 60%, but up to 80% is possible. This should not be confused with the volumetric efficiency, which relates the volume of water delivered to total water taken from the source. The portion of water available at the delivery pipe will be reduced by the ratio of the delivery head to the supply head. Thus if

1813-454: The source is 2 metres (6.6 ft) above the ram and the water is lifted to 10 metres (33 ft) above the ram, only 20% of the supplied water can be available, the other 80% being spilled via the waste valve. These ratios assume 100% energy efficiency. Actual water delivered will be further reduced by the energy efficiency factor. In the above example, if the energy efficiency is 70%, the water delivered will be 70% of 20%, i.e. 14%. Assuming

1862-401: The supply pipe to fill with water and for any air bubbles to travel up the pipe to the source. This may take some time, depending on supply pipe length and diameter. Then it can be started manually by pushing it down a few times as described above. Having a valve on the delivery pipe at the ram makes starting easier. Closing the valve until the ram starts cycling, then gradually opening it to fill

1911-406: The thin copper telephone lines increasing their weight. This and fresh snowfalls stretched the copper wires until they reached the ground. The multiple overhead open-wire phone lines were after the winter replaced by a single multi-core cable suspended from the poles. A few years later the cable was buried in the fields north of East Dundry Lane and the poles were removed. A fibre link to East Dundry

1960-450: The top field opposite The Rookery. The original settlements probably owed their existence to the quarrying of the local Dundry stone, which is found at Cardiff Castle and was used in mediaeval Bristol. Nearby Dundry originally had a Roman fort built as part of the local defences against Anglo-Saxon invasions. The hamlet today has some 16 houses including one active farm (mostly successful breeding turkeys): there were five active farms until

2009-470: The vertical distance between the source and the ram. Commercial rams may have an input fitting designed to accommodate this optimum slope . The diameter of the supply pipe would normally match the diameter of the input fitting on the ram, which in turn is based on its pumping capacity. The drive pipe should be of constant diameter and material, and should be as straight as possible. Where bends are necessary, they should be smooth, large diameter curves. Even

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2058-525: The war, refugees from the bombing of Bristol stayed for instance in Spring Farm. Two land girls helped in Walnut Farm and two in Spring Farm. Bombs and shrapnel fell in East Dundry: bombs fell in the bull pen of North Hill Farm on 3 January 1941. Incendiary bombs fell in the hamlet, for instance in the farmyard of Spring Farm. Two East Dundry men were responsible in a rota every night as fire watchers for

2107-473: The waste valve back open and allows the process to begin again. A pressure vessel [6] containing air cushions the hydraulic pressure shock when the waste valve closes, and it also improves the pumping efficiency by allowing a more constant flow through the delivery pipe. Although the pump could in theory work without it, the efficiency would drop drastically and the pump would be subject to extraordinary stresses that could shorten its life considerably. One problem

2156-467: The waste valve is in the raised (closed) position, it must be pushed down manually into the open position and released. If the flow is sufficient, it will then cycle at least once. If it does not continue to cycle, it must be pushed down repeatedly until it cycles continuously on its own, usually after three or four manual cycles. If the ram stops with the waste valve in the down (open) position it must be lifted manually and kept up for as long as necessary for

2205-409: The water flow in the inlet pipe against the now closed waste valve causes a water hammer that raises the pressure in the pump beyond the pressure caused by the water column pressing down from the outlet. This pressure differential now opens the delivery valve [5], and forces some water to flow into the delivery pipe [3]. Because this water is being forced uphill through the delivery pipe farther than it

2254-559: The way some 6 kilometres from the Chew Magna manual telephone exchange . Due to the Second World War and the following austerity, two houses often shared one of the few available lines with party lines (for example The Dingle had the number Chew Magna 81 from 1931 and the neighbouring North Hill Cottage later shared the line with Chew Magna 1081). In the late 1950s Bristol's automatic Strowger Bedminster exchange 66xxxx numbers served

2303-407: Was a "marvelous" invention, apparently independent, which lifted water 110 feet (34 m) to provide irrigation. The ram survives and is listed on the U.S. National Register of Historic Places . By the end of the twentieth century, interest in hydraulic rams has revived, due to the needs of sustainable technology in developing countries , and energy conservation in developed ones. An example

2352-772: Was made in the early 2020s underground west-to-east in the fields on the north side of East Dundry Lane, and distributed overhead to most of East Dundry properties. The Tithe Acts of 1936 and 1951 established the compulsory redemption of English tithes by the state where the annual amounts payable were less than £1, so abolishing the bureaucracy and costs of collecting small sums of money. This applied to East Dundry as elsewhere. The plant pathologist Lawrence Ogilvie lived in The Dingle (now Dingle House). The sculptor Doris Kathleen Flinn lived in The Rookery. Dundry Hill Dundry Hill

2401-421: Was only supplied to the hamlet in 1957/8 after negotiations since 1952. Dundry village had mains water supplied years earlier than East Dundry. Gas was first supplied in the 1960s when a gas main to Chew Magna was routed through East Dundry passing up from Bristol along the track north of North Hill Farm, down the hamlet's lane to Cross Cottage, down in the field at the west end of Cross Cottage's garden, along

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