Hydraulic power network

The pumping station and hydraulic accumulator at Bristol Docks

A hydraulic power network is a system of interconnected pipes carrying pressurized liquid used to transmit mechanical power from a power source, like a pump, to hydraulic equipment like lifts or motors. The system is analogous to an electrical grid transmitting power from a generating station to end-users. Only a few hydraulic power transmission networks are still in use; modern hydraulic equipment has a pump built into the machine. In the late 19th century, a hydraulic network might have been used in a factory, with a central steam engine or water turbine driving a pump and a system of high-pressure pipes transmitting power to various machines.

The idea of a public hydraulic power network was suggested by Joseph Bramah in a patent obtained in 1812. William Armstrong began installing systems in England from the 1840s, using low-pressure water, but a breakthrough occurred in 1850 with the introduction of the hydraulic accumulator, which allowed much higher pressures to be used. The first public network, supplying many companies, was constructed in Kingston upon Hull, England. The Hull Hydraulic Power Company began operation in 1877, with Edward B. Ellington as its engineer. Ellington was involved in most of the British networks, and some further afield. Public networks were constructed in Britain at London, Liverpool, Birmingham, Manchester and Glasgow. There were similar networks in Antwerp, Melbourne, Sydney, Buenos Aires and Geneva. All of the public networks had ceased to operate by the mid-1970s, but Bristol Harbour still has an operational system, with an accumulator situated outside the main pumphouse, enabling its operation to be easily visualised.

History

Joseph Bramah, an inventor and locksmith living in London, registered a patent at the London Patent Office on 29 April 1812, which was principally about a provision of a public water supply network, but included a secondary concept for the provision of a high-pressure water main, which would enable workshops to operate machinery. The high-pressure water would be applied "to a variety of other useful purposes, to which the same has never before been so applied." Major components of the system were a ring main, into which a number of pumping stations would pump the water, with pressure being regulated by several air vessels or loaded pistons. Pressure relief valves would protect the system, which he believed could deliver water at a pressure of "a great plurality of atmospheres", and in concept, this was how later hydraulic power systems worked.^[1]

In Newcastle upon Tyne, a solicitor called William Armstrong, who had been experimenting with water-powered machines, was working for a firm of solicitors who were appointed to act on behalf of the Whittle Dene Water Company. The water company had been set up to supply Newcastle with drinking water, and Armstrong was appointed secretary at the first meeting of shareholders. Soon afterwards, he wrote to Newcastle Town Council, suggesting that the cranes on the quay should be converted to hydraulic power. He was required to carry out the work at his own expense, but would be rewarded if the conversion was a success. It was, and he set up the Newcastle Cranage Company, which received an order for the conversion of the other four cranes. Further work followed, with the engineer from Liverpool Docks visiting Newcastle and being impressed by a demonstration of the crane's versatility, given by the crane driver John Thorburn, known locally as "Hydraulic Jack".^[2]

While the Newcastle system ran on water from the public water supply, the crane installed by Armstrong at Burntisland was not located where such an option was possible, and so he built a 180-foot (55 m) tower, with a water tank at the top, which was filled by a 6 hp (4.5 kW) steam engine. At Elswick in Glasgow, charges by the Corporation Water Department for the water used persuaded the owners that the use of a steam-powered crane would be cheaper.^[3] Bramah's concept of "loaded pistons" was introduced in 1850, when the first hydraulic accumulator was installed as part of a scheme for cranes for the Manchester, Sheffield and Lincolnshire Railway. A scheme for cranes at Paddington the following year specified an accumulator with a 10-inch (250 mm) piston and a stroke of 15 feet (4.6 m), which enabled pressures of 600 pounds per square inch (41 bar) to be achieved. Compared to the 80 psi (5.5 bar) of the Newcastle scheme, this increased pressure significantly reduced the volumes of water used. Cranes were not the only application, and hydraulic operation of the dock gates at Swansea reduced the operating time from 15 to two minutes, and the number of men required to operate them from twelve to four.^[4] Each of these schemes was for a single customer, and the application of hydraulic power more generally required a new model.

Public power

Machell Street hydraulic pumping station in Hull, showing the water settling tank on the roof

The first practical installation which supplied hydraulic power to the public was in Kingston upon Hull, in England. The Hull Hydraulic Power Company began operation in 1876. They had 2.5 miles (4.0 km) of pipes, which were up to 6 inches (150 mm) in diameter, and ran along the west bank of the River Hull from Sculcoates bridge to its junction with the Humber. The pumping station was near the north end of the pipeline, on Machell Street, near the disused Scott Street bascule bridge, which was powered hydraulically. There was an accumulator at Machell Street, and another one much nearer the Humber, on the corner of Grimsby Lane. Special provision was made where the pressure main passed under the entrance to Queens Dock.^[5] By 1895, pumps rated at 250 hp (190 kW) pumped some 500,000 imperial gallons (2,300 m³) of water into the system each week, and 58 machines were connected to it. The working pressure was 700 psi (48 bar), and the water was used to operate cranes, dock gates, and a variety of other machinery connected with ships and shipbuilding. The Hull system lasted until the 1940s, when the systematic bombing of the city during the Second World War led to the destruction of much of the infrastructure,^[6] and the company was wound up in 1947,^[7] when Mr F J Haswell, who had been the manager and engineer since 1904, retired.^[8]

The man responsible for the Hull system was Edward B. Ellington, who had risen to become the managing director of the Hydraulic Engineering Company, based in Chester, since first joining it in 1869. At the time of its installation, such a scheme seemed like "a leap in the dark", according to R. H. Tweddell writing in 1895, but despite a lack of enthusiasm for the scheme, Ellington pushed ahead and used it as a test bed for both the mechanical and the commercial aspects of the idea. He was eventually involved on some level in most of the hydraulic power networks of Britain. The success of such systems led to them being installed in places as far away as Antwerp in Belgium, Melbourne and Sydney in Australia, and Buenos Aires in Argentina.^[9]

The best-known public hydraulic network was the city-wide network of the London Hydraulic Power Company. This was formed in 1882, as the General Hydraulic Power Company, with Ellington as the consulting engineer. By 1883, another enterprise, the Wharves and Warehouses Steam Power and Hydraulic Pressure Company, had begun to operate, with 7 miles (11 km) of pressure mains on both sides of the River Thames. These supplied cranes, dock gates, and other heavy machinery. Under the terms of an Act of Parliament obtained in 1884, the two companies amalgamated, and became the London Hydraulic Power Company. Initially supplying 17.75 million gallons (80.7 Megalitres) of high-pressure water each day, this had risen to 1,650 million gallons (7,500 Megalitres) by 1927, when the company was powering around 8,000 machines from the supply. They maintained 184 miles (296 km) of mains at 700 psi (48 bar), which covered an area reaching Pentonville in the north, Limehouse in the east, Nine Elms and Bermondsey in the south and Earls Court and Notting Hill in the west.^[10]

The preserved pumping equipment in Wapping pumping station, which was owned by the London Hydraulic Power Company

Five pumping stations kept the mains pressurised, assisted by accumulators. The original station was at Falcon Wharf, Bankside, but this was replaced by four stations at Wapping, Rotherhithe, Grosvenor Road in Pimlico and City Road in Clerkenwell. A fifth station at East India Docks was originally operated by the Port of London Authority, but was taken over and connected to the system. The stations used steam engines until 1953, when Grosvenor Road station was converted to use electric motors, and following the success of this project, the other four were also converted. The electric motors allowed much smaller accumulators to be used, since they were then only controlling the pressure and flow, rather than storing power. While the network supplied lifts, cranes and dockgates, it also powered the cabaret platform at the Savoy Hotel, and from 1937, the 720-tonne three-section central floor at the Earls Court Exhibition Centre, which could be raised or lowered relative to the main floor to convert between a swimming pool and an exhibition hall.^[11][12] The London system contracted during the Second World War, due to the destruction of customer's machinery and premises. Following the hostilities, large areas of London were reconstructed, and the re-routing of pressure mains was much more difficult than the provision of an electric supply, so that by 1954 the number of machines had fallen to 4286.^[13] The company was wound up in 1977.

A system began operating in Liverpool in 1888.^[14] It was an offshoot of the London-based General Hydraulic Power Company, and was authorised by acts of Parliament obtained in 1884 and 1887.^[15] By 1890, some 16 miles (26 km) of mains had been installed, supplied by a pumping station at Athol Street, on the bank of the Leeds and Liverpool Canal. Although water was originally taken from the canal, cleaner water supplied by Liverpool Corporation was in use by 1890, removing the need for a filtration plant. At this time two pumpsets were in use, and a third was being installed. Pressure was maintained by two accumulators, each with an 18-inch (460 mm) diameter piston with a stroke of 20 feet (6.1 m). The Practical Engineer quoted the pressure as 75 pounds per square inch (5.2 bar),^[16] but this is unlikely to be correct by comparison with other systems. A second pumping station at Grafton Street was operational by 1909.^[17] The system ceased operation in 1971.^[18]

Birmingham obtained its system in 1891, when the Dalton Street hydraulic station opened. In an unusual move, J. W. Gray, the Water Department engineer for the city, had been laying pressure mains beneath the streets for some years, anticipating the need for such a system. The hydraulic station used Otto 'Silent' type gas engines, and had two accumulators, with an 18-inch (460 mm) diameter piston, a stroke of 20 feet (6.1 m) and each loaded with a 93-tonne weight. The gas engines were started by a small hydraulic engine, which used the hydraulic energy stored in the accumulators, and all equipment was supplied by Ellington's company. Very few documents describing the details of the system are known to exist.^[19]

The final two public systems in Britain were in Manchester, commissioned in 1894, and Glasgow, commissioned the following year. Both were equipped by Ellington's company, and used the higher pressure of 1,120 psi (77 bar). This was maintained by six sets of triple-expansion steam engines, rated at 200 hp (150 kW) each. Two accumulators with pistons of 18-inch (460 mm) diameter, a stroke of 23 feet (7.0 m), and loaded with 127 tonnes were installed. In Manchester, the hydraulic station was built on the east side of Gloucester Street,^[20] by Oxford Road railway station. It was later supplemented by stations at Water Street and Pott Street, the latter now under the car parks of the Central Retail Park.^[21] At its peak in the 1930s, the system consisted on 35 miles (56 km) of pipes, which were connected to 2,400 machines, most of which were used for baling cotton.^[22] The system was shut down in 1972.^[21] In Glasgow, the pumping station was at the junction of High Street and Rottenrow. By 1899, it was supplying power to 348 machines, and another 39 were in the process of being completed.^[20] The pipes were 7 inches (180 mm) in diameter, and there were around 30 miles (48 km) of them by 1909, when 202,141 imperial gallons (918.95 m³) of high pressure water were supplied to customers. The system was shut down in 1964.^[23]

Other systems

All of the British systems were designed to provide power for intermittent processes, such as the operation of dock gates or cranes. The system installed at Antwerp was somewhat different, in that its primary purpose was the production of electricity for lighting. It was commissioned in 1894, and used pumping engines producing a total of 1,000 hp (750 kW) to supply water at 750 psi (52 bar). Ellington, writing in 1895, stated that he found it difficult to see that this was an economical use of hydraulic power, although tests conducted at his works at Chester in October 1894 showed that efficiencies of 59 per cent could be achieved using a Pelton wheel directly coupled to a dynamo.^[24]

Two major systems were built in Australia. The first was in Melbourne, where the Melbourne Hydraulic Power Company began operating in July 1889.^[25] The company was authorised by an Act of the Victorian Parliament passed in December 1887, and construction of the system began, with Coates & Co. acting as consulting engineers, and George Swinburne working as engineering manager. The steam pumping plant was supplied by Abbot & Co. from England. Expansion was rapid, with around 70 machines, mainly hydraulic lifts, connected to the system by the end of 1889, and a third steam engine had to be installed in mid-1890, which more than doubled the capacity of the system. A fourth pumping engine was added in 1891, by which time there were 100 customers connected to the mains. The mains were a mixture of 4-inch (100 mm) and 6-inch (150 mm) pipes. The water was extracted from the Yarra River until 1893, after which it was drawn from the Public Works Department's supply. There were some 16 miles (26 km) of mains by 1897. A second pumping station was added in 1901, and in 1902, 102 million gallons (454 Megalitres) of pressurised water were used by customers.^[26]

The system was operated as a commercial enterprise until 1925, after which the business and its assets reverted to the City of Melbourne, as specified by the original act. One of the early improvements made by the City Council was to consolidate the system. The steam pumps were replaced by new electric pumps, located in the Spencer Street power station, which thus supplied both electric power and hydraulic power to the city. The hydraulic system continued to operate under municipal ownership until December 1967.^[26]

In January 1891, a system in Sydney came on-line, having been authorised by act of Parliament in 1888. George Swinburne was again the engineer, and the system was supplying power to around 200 machines by 1894, which included 149 lifts and 20 dock cranes.^[27] The operating company was the Sydney and Suburbs Hydraulic Power Company,^[28] later shortened to the Sydney Hydraulic Power Company. Pressure mains were either of 4-inch (100 mm) or 6-inch (150 mm) diameter, and at its peak, there were around 50 miles (80 km) of mains,^[29] covering an area between Pyrmont, Woolloomooloo and Broadway. In 1919, most of the 2369 lifts in the metropolitan area were hydraulically operated.^[27] The pumping station, together with two accumulators, was situated in the Darling Harbour district, and the original steam engines were replaced by three electric motors driving centrifugal pumps in 1952.^[30] The scheme remained in private ownership until its demise in 1975, and the pumping station has since been re-used as a tavern.^[26]

Ellington's system in Buenos Aires was designed to operate a sewage pumping scheme in the city.^[31]

Summary

Legacy

The external hydraulic accumulator at Bristol Harbour

Geneva had a hydraulic network with a total installed power of 6,000 hp (4,500 kW). The system gave birth to the Jet d'Eau, a huge fountain which was originally only a pressure relief valve for the network when the consumers had been switched off.

Bristol Harbour still has a working system, the pumping machinery of which was supplied by Fullerton, Hodgart and Barclay of Paisley, Scotland in 1907. The engine house is a grade II* listed building, constructed in 1888, with a tower at one end to house the hydraulic accumulator.^[32] A second accumulator was fitted outside the building in the 1920s, which enables the operation of the system to be more easily visualised.

A number of artifacts, including the buildings used as pumping stations, have survived the demise of public hydraulic power networks. In Hull, the Machell Street pumping station has been reused as a workshop. The building still supports the sectional cast-iron roof tank used to allow the silt-laden water of the River Hull to settle, and is marked by a Blue plaque, to commemorate its importance.^[7] In London, Bermondsey pumping station, built in 1902, is in use as an engineering works, but retains its chimney and accumulator tower,^[33] while the station at Wapping is virtually complete, retaining all of its equipment, which is still in working order. The building is grade II* listed because of its completeness.^[34]

In Manchester, the Water Street pumping station, built in Baroque style between 1907 and 1909, was used as workshops for the City College,^[35] but has formed part of the People's History Museum since 1994. One of the pumping sets has been moved to the Museum of Science and Industry, where it has been restored to working order and forms part of a larger display about hydraulic power.^[21] The pumps were made by the Manchester firm of Galloways.^[22]

See also

• Power transmission
• Pumped-storage hydroelectricity
• Pneumatic tube

Bibliography

References

Literature