A safety valve is a valve that acts as a fail-safe. An example of safety valve is a pressure relief valve, which automatically releases a substance from a boiler, pressure vessel, or other system, when the pressure or temperature exceeds preset limits. Pilot-operated relief valves are a specialized type of pressure safety valve. A leak tight, lower cost, single emergency use option would be a rupture disk. Safety valves were first developed for use on steam boilers during the Industrial Revolution. Early boilers operating without them were prone to explosion unless operated. Vacuum safety valves are used to prevent a tank from collapsing while it is being emptied, or when cold rinse water is used after hot CIP or SIP procedures; when sizing a vacuum safety valve, the calculation method is not defined in any norm in the hot CIP / cold water scenario, but some manufacturers have developed sizing simulations. The earliest and simplest safety valve was used on a 1679 steam digester and utilized a weight to retain the steam pressure.
On the Stockton and Darlington Railway, the safety valve tended to go off when the engine hit a bump in the track. A valve less sensitive to sudden accelerations used a spring to contain the steam pressure, but these could still be screwed down to increase the pressure beyond design limits; this dangerous practice was sometimes used to marginally increase the performance of a steam engine. In 1856, John Ramsbottom invented a tamper-proof spring safety valve that became universal on railways; the Ramsbottom valve consisted of two plug-type valves connected to each other by a spring-laden pivoting arm, with one valve element on either side of the pivot. Any adjustment made to one of valves in an attempt to increase its operating pressure would cause the other valve to be lifted off its seat, regardless of how the adjustment was attempted; the pivot point on the arm was not symmetrically between the valves, so any tightening of the spring would cause one of the valves to lift. Only by removing and diassembling the entire valve assembly could its operating pressure be adjusted, making impromptu'tying down' of the valve by locomotive crews in search of more power impossible.
The pivoting arm was extended into a handle shape and fed back into the locomotive cab, allowing crews to'rock' both valves off their seats to confirm they were set and operating correctly. Safety valves evolved to protect equipment such as pressure vessels and heat exchangers; the term safety valve should be limited to compressible fluid applications. The two general types of protection encountered in industry are thermal protection and flow protection. For liquid-packed vessels, thermal relief valves are characterized by the small size of the valve necessary to provide protection from excess pressure caused by thermal expansion. In this case a small valve is adequate because most liquids are nearly incompressible, so a small amount of fluid discharged through the relief valve will produce a substantial reduction in pressure. Flow protection is characterized by safety valves that are larger than those mounted for thermal protection, they are sized for use in situations where significant quantities of gas or high volumes of liquid must be discharged in order to protect the integrity of the vessel or pipeline.
This protection can alternatively be achieved by installing a high integrity pressure protection system. In the petroleum refining, chemical manufacturing, natural gas processing, power generation, drinks and pharmaceuticals industries, the term safety valve is associated with the terms pressure relief valve, pressure safety valve and relief valve; the generic term is pressure safety valve. PRVs and PSVs are not the same thing, despite. Relief valve: an automatic system, actuated by the static pressure in a liquid-filled vessel, it opens proportionally with increasing pressure. Safety valve: an automatic system that relieves the static pressure on a gas, it opens accompanied by a popping sound. Safety relief valve: an automatic system that relieves by static pressure on both gas and liquid. Pilot-operated safety relief valve: an automatic system that relieves on remote command from a pilot, to which the static pressure is connected. Low pressure safety valve: an automatic system that relieves static pressure on a gas.
Used when the difference between the vessel pressure and the ambient atmospheric pressure is small. Vacuum pressure safety valve: an automatic system that relieves static pressure on a gas. Used when the pressure difference between the vessel pressure and the ambient pressure is small and near to atmospheric pressure. Low and vacuum pressure safety valve: an automatic system that relieves static pressure on a gas. Used when the pressure difference is small, negative or positive and near to atmospheric pressure. RV, SV and SRV are spring-operated. LPSV and VPSV are weight-loaded. In most countries, industries are required to protect pressure vessels and other equipment by using relief valves. In most countries, equipment design codes such as those provided by the ASME, API and other organizations like ISO mus
East London Harbour 0-4-0VB
The East London Harbour 0-4-0VB of 1873 was a South African steam locomotive from the pre-Union era in the Cape of Good Hope. In 1847, the government of the Cape of Good Hope established harbour boards at its three major ports, Table Bay, Port Elizabeth and East London. While railway lines were laid at all these harbours, trains were for the most part hauled by oxen or mules; the first steam locomotive to see service at East London Harbour was a 7 ft 1⁄4 in Brunel gauge engine, obtained for work on breakwater construction in 1873 and placed in service in 1874. It was a 0-4-0 vertical boiler engine, similar in general appearance to the American Grasshopper type. Four of them were acquired between 1873 and 1880; when the requirement for improved harbour facilities for the handling of ships and cargoes became apparent, the Cape Government established harbour boards at Table Bay, Port Elizabeth and East London in 1847. Each board consisted of five members increased to seven, they were responsible for the management, improvement and maintenance of the facilities at these ports and empowered to levy wharfage dues.
Railway lines were an early feature at all these harbours. East London Harbour was surveyed by Sir John Coode in 1870 and breakwater construction began in 1872, under the supervision of resident engineer William Lester; the first of four stone quarries to supply rock for the construction of the breakwaters was opened in June 1872 and made use of convict labour and oxen-drawn rail trucks. Construction of the South Breakwater, on the west bank of the Buffalo River, was completed by August 1873; the wide 7 ft 1⁄4 in Brunel gauge track was used during breakwater construction at both East London and Table Bay harbours to make it easier to drop rock from the wagons between the rails, which were run out to sea on a timber framework. This method of construction was perfected by Sir John Coode; the first locomotives at East London Harbour were acquired for breakwater construction and the first of four steam locomotives was delivered in 1873. It was ordered from Alexander Chaplin & Co. in Glasgow and though it arrived on 2 July 1873, it was only placed in service on 17 August 1874 when it was used for passenger rides on the first day, before being put to construction work.
Three more of these locomotives were acquired from Alexander Chaplin, one more in 1874 and another two in 1879 and early 1880. The locomotive, with a 0-4-0 wheel arrangement, a vertical boiler and vertical cylinders, was similar in general appearance to the Grasshopper type locomotive which appeared on the Baltimore and Ohio Railroad in the United States of America in 1832 and whose name seems to have come from the movement of the exposed vertical valve gear. While little is known about the locomotive, it appears from the existing photograph to have been wood-fired and driven by a marine type of vertical engine. Alexander Chaplin produced a range of steam-powered industrial products which included steam cranes, locomotives and winding engines, ship's deck engines and sea water distilling apparatus. Between 1860 and 1899, it delivered 135 of these locomotives to customers around the world. All four engines were used during construction and also worked as shunting locomotives on the West Bank lines of the East London Harbour.
At least one of them survived into the 20th century, since the Harbour Board reports still listed one "old 15 HP locomotive" on the books in 1904. The Brunel gauge lines were regauged or closed between 1909 and 1912. In South Africa, the locomotive type was not unique to East London Harbour and several others saw service on industrial lines; the locomotive works numbers and dates of completion are listed in the table
Table Bay Harbour 0-4-0WT
The Table Bay Harbour 0-4-0WT of 1879 was a South African steam locomotive from the pre-Union era in the Cape of Good Hope. Altogether seven Brunel gauge locomotives are known to have been employed on the Table Bay Harbour project between 1862 and 1904; the fourth of these construction locomotives was a 7 ft 1⁄4 in Brunel gauge 0-4-0 well-tank engine which entered excavation and breakwater construction service in 1879. Work to improve the facilities at Table Bay Harbour in Cape Town was started in 1860, using convict labour, consisted of the excavation of two basins and the construction of breakwater piers; the construction locomotives at Table Bay Harbour were small 7 ft 1⁄4 in Brunel gauge engines which were used to haul trains of heavy iron tip-trucks to convey rock from the Alfred Basin excavation site to the breakwater, being built simultaneously. The broad Brunel gauge track was selected to make it easier to drop rock from the trucks between the rails which were run out to sea on a timber framework, a method of construction, perfected by Sir John Coode.
The trucks were equipped with interlocking running boards along the length of the train. As work progressed, the requirement arose for more locomotives. Altogether seven Brunel gauge locomotives are known to have been employed on the Table Bay Harbour project, but information about all of them are sketchy at best. Three locomotives were placed in service before 1879, one in 1862 and another at some stage between 1863 and 1870; the third locomotive was a 0-4-0 side-tank engine, obtained from Fletcher and Company in 1874. In 1879, the fourth locomotive to enter service on the construction site at Table Bay Harbour was the 0-4-0 well-tank engine, the subject of this page, it was obtained from Fletcher, not from Black and Company as mentioned in D. F. Holland’s work, it was similar to the third locomotive of 1874. It offered the crew some better protection against the elements with a larger roofed cab and a rather ornate wooden frame front screen with five windows. After completion of the first basin, named after Prince Alfred, work on the project continued into the 20th century since further harbour expansion soon became necessary, brought about by developments in the interior such as the discovery of diamonds and gold and the outbreak of the Second Boer War.
A dry dock was added in 1881 and work on a new breakwater and the Victoria Basin began in 1900. The Brunel gauge harbour construction railway remained in operation until 1904
In rail transport, track gauge or track gage is the spacing of the rails on a railway track and is measured between the inner faces of the load-bearing rails. All vehicles on a rail network must have running gear, compatible with the track gauge, in the earliest days of railways the selection of a proposed railway's gauge was a key issue; as the dominant parameter determining interoperability, it is still used as a descriptor of a route or network. In some places there is a distinction between the nominal gauge and the actual gauge, due to divergence of track components from the nominal. Railway engineers use a device, like a caliper, to measure the actual gauge, this device is referred to as a track gauge; the terms structure gauge and loading gauge, both used, have little connection with track gauge. Both refer to two-dimensional cross-section profiles, surrounding the track and vehicles running on it; the structure gauge specifies the outline into which altered structures must not encroach.
The loading gauge is the corresponding envelope within which rail vehicles and their loads must be contained. If an exceptional load or a new type of vehicle is being assessed to run, it is required to conform to the route's loading gauge. Conformance ensures. In the earliest days of railways, single wagons were manhandled on timber rails always in connection with mineral extraction, within a mine or quarry leading from it. Guidance was not at first provided except by human muscle power, but a number of methods of guiding the wagons were employed; the spacing between the rails had to be compatible with that of the wagon wheels. The timber rails wore rapidly. In some localities, the plates were made L-shaped, with the vertical part of the L guiding the wheels; as the guidance of the wagons was improved, short strings of wagons could be connected and pulled by horses, the track could be extended from the immediate vicinity of the mine or quarry to a navigable waterway. The wagons were built to a consistent pattern and the track would be made to suit the wagons: the gauge was more critical.
The Penydarren Tramroad of 1802 in South Wales, a plateway, spaced these at 4 ft 4 in over the outside of the upstands. The Penydarren Tramroad carried the first journey by a locomotive, in 1804, it was successful for the locomotive, but unsuccessful for the track: the plates were not strong enough to carry its weight. A considerable progressive step was made. Edge rails required a close match between rail spacing and the configuration of the wheelsets, the importance of the gauge was reinforced. Railways were still seen as local concerns: there was no appreciation of a future connection to other lines, selection of the track gauge was still a pragmatic decision based on local requirements and prejudices, determined by existing local designs of vehicles. Thus, the Monkland and Kirkintilloch Railway in the West of Scotland used 4 ft 6 in; the Arbroath and Forfar Railway opened in 1838 with a gauge of 5 ft 6 in, the Ulster Railway of 1839 used 6 ft 2 in Locomotives were being developed in the first decades of the 19th century.
His designs were so successful that they became the standard, when the Stockton and Darlington Railway was opened in 1825, it used his locomotives, with the same gauge as the Killingworth line, 4 ft 8 in. The Stockton and Darlington line was immensely successful, when the Liverpool and Manchester Railway, the first intercity line, was built, it used the same gauge, it was hugely successful, the gauge, became the automatic choice: "standard gauge". The Liverpool and Manchester was followed by other trunk railways, with the Grand Junction Railway and the London and Birmingham Railway forming a huge critical mass of standard gauge; when Bristol promoters planned a line from London, they employed the innovative engineer Isambard Kingdom Brunel. He decided on a wider gauge, to give greater stability, the Great Western Railway adopted a gauge of 7 ft eased to 7 ft 1⁄4 in; this became known as broad gauge. The Great Western Railway was successful and was expanded and through friendly associated companies, widening the scope of broad gauge.
At the same time, other parts of Britain built railways to standard gauge, British technology was exported to European countries and parts of North America using standard gauge. Britain polarised into two areas: those that used standard gauge. In this context, standard gauge was referred to as "narrow gauge" to indicate the contrast; some smaller concerns selected other non-standard gauges: the Eastern Counties Railway adopted 5 ft. Most of them converted to standard gauge at an early date, but the GWR's broad gauge continued to grow; the larger railway companies wished to expand geographically, large areas were considered to be under their control. When a new
CGR 0-4-0ST 1873
The Cape Government Railways 0-4-0ST of 1873 was a South African steam locomotive from the pre-Union era in the Cape of Good Hope. In 1873, two Cape gauge saddle-tank locomotives with a 0-4-0 wheel arrangement were placed in construction service by Mac Donald & Company, contractors to the Port Elizabeth and Uitenhage Railway Company; when the contract was completed in 1875, the railway and the locomotives were taken over by the Midland System of the Cape Government Railways. A third locomotive, built to the same design, was delivered to the Western System in Cape Town in 1874; these were the first Cape gauge. When the control of railways in the Cape of Good Hope was taken over by the Colonial Government on 1 January 1873 and the Cape Government Railways was established with the object of railways expansion, a Select Committee was appointed to study the question of track gauge; the choice which had to be made was between the existing Standard gauge of 4 feet 8 1⁄2 inches and the narrower gauge of 2 feet 6 inches, which would effect savings of up to one-third on construction cost.
The CGR Chief Railway Engineer William George Brounger was opposed to the adoption of a narrower gauge on the grounds that, while initial cost would be less, operating costs would be higher. The narrow gauge had been proposed by civil engineer R. Thomas Hall, Superintendent of the narrow gauge Redruth and Chacewater Railway in Cornwall, involved in the construction, beginning in 1869, of the Namaqualand Railway, being built to that gauge between Port Nolloth and O'okiep for the Cape Copper Mining Company; the committee, with a three-to-one vote, settled on a compromise between the two recommended gauges and the 3 feet 6 inches Cape gauge came into existence in Southern Africa. The first three locomotives for the new Cape gauge lines were built by Manning Wardle & Company in 1873 and 1874; the first two, ex works on 12 March and 3 May 1873 were delivered in 1873 to Mac Donald & Company, contractors to the Port Elizabeth and Uitenhage Railway Company in Port Elizabeth. The contractors named them Little Bess respectively.
The third locomotive, ex works on 6 February 1874, was delivered to the Western System in Cape Town in 1874 and was numbered W46 in the Western's number range. From the arrival of the first railway locomotive in South Africa, the Cape Town Railway & Dock 0-4-0T of 1859, all railway rolling stock had been equipped with buffers-and-chain coupling, variations of which are still in use in the United Kingdom and Europe; these locomotives of 1873 introduced the bell-shaped Johnston link-and-pin coupler known as a bell link-and-pin coupler, to become the standard coupler on Cape gauge rolling stock in the Cape of Good Hope, the Colony of Natal and the Zuid-Afrikaansche Republiek. In South Africa, all new Cape gauge locomotives and rolling stock acquired between 1873 and 1927 were equipped with these or similar couplers. By 1872, Port Elizabeth possessed extensive Standard gauge trackage between the harbour and Swartkops, but trains were still animal-hauled. Work by contractors Mac Donald's on railway expansion from Port Elizabeth into the interior commenced in June 1872.
The two locomotives which were delivered to them in 1873 were utilised as construction engines. The first train ran as far as Sydenham in October 1873, 11 miles of railway was completed by 1874; when the two new lines were opened in 1875, northwestward to Uitenhage and northward from Swartkops to Barkly Bridge, the lines and the construction locomotives were taken over by the CGR and the locomotives were numbered M1 and M2 for the Midland System. These two locomotives, together with a smaller 0-4-0ST engine named Mliss which joined them on construction work in 1874, are considered the pioneers of locomotives over the greater part of the Midland System. By 1874, when the third of the first three locomotives, no. W46, was delivered to the Western System, construction work was proceeding in two directions from Wellington. New Cape gauge track was being laid deeper into the interior towards Worcester, while track dual-gauging was being undertaken back from Wellington towards Cape Town
3 ft 6 in gauge railways
Railways with a track gauge of 3 ft 6 in / 1,067 mm were first constructed as horse-drawn wagonways. From the mid-nineteenth century, the 3 ft 6 in gauge became widespread in the British Empire, was adopted as a standard in Japan and Taiwan. There are 112,000 kilometres of 1,067 mm gauge track in the world. 1795 One of the first railways to use 3 ft 6 in gauge was the Little Eaton Gangway in England, constructed as a horse-drawn wagonway in 1795. Other 3 ft 6 in gauge wagonways in England and Wales were built in the early nineteenth century. 1862 In 1862 the Norwegian engineer Carl Abraham Pihl constructed the first 3 ft 6 in gauge railway in Norway, the Røros Line. 1865 In 1865 the Queensland Railways were constructed. Its 3 ft 6 in gauge was promoted by the Irish engineer Abraham Fitzgibbon and consulting engineer Charles Fox. 1867 In 1867, the construction of the railroad from the Castillo de Buitrón mine to the pier of San Juan del Puerto, Spain, began. The width was 3 ft 6 in. 1868 In 1868 Charles Fox asks civil engineer Edmund Wragge to survey a 3 ft 6 in railway in Costa Rica.
1871 In 1871 the Canadian Toronto and Bruce Railway and the Toronto and Nipissing Railway were opened, promoted by Pihl and Fitzgibbon and surveyed by Wragge as an engineer of Fox. 1872 In January 1872 Robert Fairlie advocated the use of 3 ft 6 in gauge in his book Railways Or No Railways: Narrow Gauge, Economy with Efficiency v. Broad Gauge, Costliness with Extravagance. 1872 saw the opening of the first 3 ft 6 in gauge railway in Japan, proposed by the British civil engineer Edmund Morel based on his experience of building railways in New Zealand. 1873 On 1 January 1873, the first 3 ft 6 in gauge railway was opened in New Zealand, constructed by the British firm John Brogden and Sons. Earlier built 4 ft 8 1⁄2 in and broad gauge railways were soon converted to the narrower gauge. In 1873 the Cape Colony adopted the 3 ft 6 in gauge. After conducting several studies in southern Europe, the Molteno Government selected the gauge as being the most economically suited for traversing steep mountain ranges.
Beginning in 1873, under supervision of Railway engineer of the Colony William Brounger, the Cape Government Railways expanded and the gauge became the standard for southern Africa. 1876 Natal converted its short 10 kilometres long Durban network from 4 ft 8 1⁄2 in standard gauge prior to commencing with construction of a network across the entire colony in 1876. Other new railways in Southern Africa, notably Mozambique, the Rhodesias and Angola, were constructed in 3 ft 6 in gauge during that time. After 1876 In the late nineteenth and early twentieth century numerous 3 ft 6 in gauge tram systems were built in the United Kingdom and the Netherlands. In Sweden, the gauge was nicknamed Blekinge gauge, as most of the railways in the province of Blekinge had this gauge. An alternate name for this gauge, Cape gauge, is named after the Cape Colony in what is now South Africa, which adopted it in 1873; the term Cape Gauge is used in other languages, such as the Dutch kaapspoor, German Kapspur, Norwegian kappspor and French voie cape.
After metrication in the 1960s, the gauge was referred to in official South African Railways publications as 1,065 mm instead of 1067 mm. The gauge name. In Australia the imperial term 3 foot 6 inch is used. In some Australian publications the term medium gauge is used, while in Australian states where 4 ft 8 1⁄2 in is the norm, 1,067 mm gauge is referred to as narrow gauge. In Japan 1,067 mm gauge is referred to as kyōki, it is defined in metric units. Similar, but incompatible without wheelset adjustment, rail gauges in respect of aspects such as cost of construction, practical minimum radius curves and the maximum physical dimensions of rolling stock are: 1,100 mm, 1,093 mm, 1,055 mm, 1,050 mm, 1,000 mm metre gauge. Cape Government Railways Heritage railway List of track gauges South African Trains – A Pictorial Encyclopaedia Why Did Japan Choose the 3'6" Narrow Gauge
Bloemfontein is the capital city of the province of Free State of South Africa. Situated at an altitude of 1,395 m above sea level, the city is home to 520,000 residents and forms part of the Mangaung Metropolitan Municipality which has a population of 747,431; the city of Bloemfontein hosts the Supreme Court of Appeal of South Africa, the Franklin Game Reserve, Naval Hill, the Maselspoort Resort and the Sand du Plessis Theatre. The city hosts numerous museums, including the National Women's Monument, the Anglo-Boer War Museum, the National Museum, the Oliewenhuis Art Museum Bloemfontein host sub-Saharan Africa's first digital planetarium, the Naval Hill Planetarium and Boyden Observatory, an astronomical research observatory erected by Harvard University. Bloemfontein is popularly and poetically known as "the city of roses", for its abundance of these flowers and the annual rose festival held there; the city's Sesotho name is Mangaung, meaning "place of cheetahs". The origin of the city's name is disputed.
It is borrowed from the Dutch words bloem and fontein, meaning fountain of flowers. Popular legends include an ox named "Bloem" owned by Rudolphus Martinus Brits, one of the pioneer farmers, taken by a lion near a fountain on his property, while another story names Jan Bloem, a Korana KhoiKhoi leader who settled there. Though a predominantly Afrikaner settlement, Bloemfontein was founded in 1846 as a fort by British army major Henry Douglas Warden as a British outpost in the Transoranje region, at that stage occupied by various groups of peoples including Cape Colony Trek Boers and Barolong. Warden chose the site because of its proximity to the main route to Winburg, the spacious open country, the absence of horse sickness. Bloemfontein was the original farm of Johannes Nicolaas Brits born 21 February 1790, owner and first inhabitant of Bloemfontein. Johann – as he was known – sold the farm to Major Warden. With colonial policy shifts, the region changed into the Orange River Sovereignty and the Orange Free State Republic.
From 1902–10 it served as the capital of the Orange River Colony and since that time as the provincial capital of the Free State. In 1910 it became the Judicial capital of the Union of South Africa The Orange Free State was an independent Boer sovereign republic in southern Africa during the second half of the 19th century. Extending between the Orange and Vaal rivers, its borders were determined by the United Kingdom of Great Britain and Ireland in 1848 when the region was proclaimed as the Orange River Sovereignty, with a seat of a British Resident in Bloemfontein; as the capital of the Orange Free State Republic the growth and maturing of the Republic resulted in the growth of Bloemfontein. Numerous public buildings that remain in use today were constructed; this was facilitated by the excellent governance of the Republic and the compensation from the British for the loss of the diamond rich Griqualand area. The old Orange Free State's presidential residence the Old Presidency is a museum and cultural space in the city.
A railway line was built in 1890 connecting Bloemfontein to Cape Town. The writer J. R. R. Tolkien was born in the city on 3 January 1892, though his family left South Africa following the death of his father, Arthur Tolkien, while Tolkien was only three, he recorded that his earliest memories were of "a hot country". In 1899 the city was the site of the Bloemfontein Conference, which failed to prevent the outbreak of the Second Boer War; the conference was a final attempt to avert a war between the South African Republic. With its failure the stage was set for war, which broke out on 11 October 1899; the rail line from Cape Town provided a centrally located railway station, proved critical to the British in occupying the city later. On 13 March 1900, following the Battle of Paardeberg, British forces captured the city and built a concentration camp nearby to house Boer women and children; the National Women's Monument, on the outskirts of the city, pays homage to the 26,370 women and children as well as 1,421 old men who died in these camps in various parts of the country.
The hill in town was named Naval Hill after the naval guns brought in by the British in order to fortify the position against attack. On 31 May 1910 eight years after the Boers signed the Peace Treaty of Vereeniging that ended the Anglo-Boer War between the British Empire and two Boer states, the South African Republic and the Orange Free State, South Africa became a Union. Due to disagreements over where the Union's capital should be, a compromise was reached that allowed Bloemfontein to host Appellate Division and become the Union's judicial capital. Bloemfontein was given financial compensation. On 8 January 1912, the South African Native National Congress was founded in Bloemfontein; the Union of South Africa had not granted rights to black South Africans, causing the organisation's creation. Its primary aim was to fight for the rights of black South Africans. From 1 to 9 January 1914, James Barry Munnik Hertzog and his supporters met in Bloemfontein to form the National Party of the Orange Free State, to