A Corliss steam engine – the valve gear is on the right of the cylinder block, on the left of the picture

A Corliss steam engine (or Corliss engine) is a steam engine, fitted with rotary valves and with variable valve timing patented in 1849, invented by and named after the US engineer George Henry Corliss of Providence, Rhode Island.

Engines fitted with Corliss valve gear offered the best thermal efficiency of any type of stationary steam engine until the refinement of the uniflow steam engine and steam turbine in the 20th century. Corliss engines were generally about 30 percent more fuel efficient than conventional steam engines with fixed cutoff.[1] This increased efficiency made steam power more economical than water power, allowing industrial development away from millponds.[2]

Corliss engines were typically used as stationary engines to provide mechanical power to line shafting in factories and mills and to drive dynamos to generate electricity. Many were quite large, standing many metres tall and developing several hundred horsepower, albeit at low speed, turning massive flywheels weighing several tons at about 100 revolutions per minute. Some of these engines have unusual roles as mechanical legacy systems and because of their relatively high efficiency and low maintenance requirements, some remain in service into the early 21st century. See, for example, the engines at the Hook Norton Brewery and the Distillerie Dillon in the list of operational engines.

Corliss engine mechanisms

Corliss engines have four valves for each cylinder, with steam and exhaust valves located at each end. Corliss engines incorporate distinct refinements in both the valves themselves and in the valve gear, that is, the system of linkages that operate the valves.

The use of separate valves for steam admission and exhaust means that neither the valves nor the steam passages between cylinders and valves need to change temperature during the power and exhaust cycle, and it means that the timing of the admission and exhaust valves can be independently controlled. In contrast, conventional steam engines have a slide valve or piston valve that alternately feeds and exhausts through passages to each end of the cylinder. These passages are exposed to wide temperature swings during engine operation, and there are high temperature gradients within the valve mechanism.

Clark (1891) commented that the Corliss gear "is essentially a combination of elements previously known and used separately, affecting the cylinder and the valve-gear".[3] The origins of the Corliss gear with regard to previous steam valve gear was traced by Inglis (1868).[4]

Corliss valve gear

"Gordon's improved Corliss valvegear", detailed view. The wrist-plate is the central plate from which rods radiate to each of the four valves.

George Corliss received U.S. patent 6,162 for his valve gear on March 10, 1849. This patent covered the use of a wrist-plate to convey the valve motion from a single eccentric to the four valves of the engine, and it covered the use of trip valves with variable cutoff under governor control that characterize Corliss Engines.[5] Unlike later engines, most of which were horizontal, this patent describes a vertical cylinder beam engine, and it used individual slide valves for admission and exhaust at each end of the cylinder.

The inlet valves are pulled open with an eccentric-driven pawl; when the pawl trips, the rapid closure is damped using a dashpot. In many engines, the same dashpot acts as a vacuum spring to pull the valves closed, but Corliss's early engines were slow enough that it was the weight of the dashpot piston and rod that closed the valve.

The speed of a Corliss engine is controlled by varying the cutoff of steam during each power stroke, while leaving the throttle wide open at all times. To accomplish this, the centrifugal governor is linked to a pair of cams, one for each admission valve. These cams determine the point during the piston stroke that the pawl will release, allowing that valve to close.

As with all steam engines where the cutoff can be regulated, the virtue of doing so lies in the fact that most of the power stroke is powered by the expansion of steam in the cylinder after the admission valve has closed. This comes far closer to the ideal Carnot cycle than is possible with an engine where the admission valve is open for the length of the power stroke and speed is regulated by a throttle valve.

The Corliss valve gearing allowed more uniform speed and better response to load changes, making it suitable for applications like rolling mills and spinning, and greatly expanding its use in manufacturing.[6][7]

Corliss valves

Sectioned cylinder, showing rotating valves
Detail of a Corliss-type valve gear and cylinder cross section showing the path of high-pressure steam (in red) and low-pressure steam (in blue). With each stroke, the four valves alternate opening and closing, driving the piston back and forth

Corliss valves open directly into the cylinder. The valves connect the cylinder to separate steam and exhaust plenums. Initially, Corliss used slide valves with linear actuators, but by 1851, Corliss had shifted to semi-rotary valve actuators, as documented in U.S. Patent 8253.[8] In this engine, the wrist plate was moved to the center of the cylinder side, as on later Corliss engines. This was still a beam engine, however, and the semi-rotary valve actuators operated linear slide valves inside the four valve chests of the engine.

Corliss valves are in the form of a minor circular segment, rotating inside a cylindrical valve-face. Their actuating mechanism is off along the axis of the valve, thus they have little "dead space" such as the stem of a poppet valve and the entire port area can be used efficiently for gas flow.

As the area of a Corliss valve is small compared to the port area, the effects of gas flow generate relatively little torque on the valve axle compared to some other sorts of valve. These advantages have led to the Corliss form of valve being used in other roles, apart from steam engines with Corliss gear.

The Rolls-Royce Merlin aero-engine used a rectangular butterfly valve as a throttle. Gas-flow forces acting asymmetrically on this butterfly could lead to poor control of the power in some circumstances. Late models, from the 134, used a Corliss throttle valve instead to avoid this problem.[9]

Barring and barring engines

A common feature of large Corliss engines is one or two sets of narrow gear teeth in the rim of the flywheel.[10] These teeth allow the flywheel to be barred, that is, turned with the aid of a crowbar.[11] This may be needed during engine maintenance, for example, to set the cutoff and admission valve timing, and it may be needed during engine starting.

The need for barring the engine during starting is most obvious on single-cylinder engines, where a careless engine operator might stop the engine with the piston in or near dead center. Once stopped in this state, the engine cannot be started under its own power, so it must be barred to a more favorable position for starting.

Large Corliss engines cannot be safely started cold,[why?] so it is common to admit low-pressure steam to both sides of the cylinder to warm up the metalwork. Turning the engine slowly during this process ensures that the entire engine is uniformly warmed, and it ensures that oil is uniformly distributed through the mechanism before applying power.[12] Again, barring may be used to do this, although operators sometimes do this by careful manual manipulation of the valves.[13]

For large engines, muscle powered barring is sufficiently difficult that barring engines are frequently installed.[14] These are small engines with gear teeth cut to mate with the teeth on the flywheel. Generally, the drive gears of the barring engine are designed to automatically disengage if the engine begins running under its own power while the barring gears are engaged.

Company history

The Corliss Steam Engine Company was originally known as Fairbanks, Clark & Co. in the 1830s. In 1843 it was renamed Fairbanks, Bancroft & Co. when Edward Bancroft joined the company. In 1846 it was renamed Bancroft, Nightingale & Co. when George H. Corliss joined the company, and in 1847 it was renamed Corliss, Nightingale and Co. In 1848 the company moved to the Charles Street Railroad Crossing in Providence, Rhode Island.

Valve gear typical of engines developed by Corliss competitors. The horizontal arrangement of the dashpots and the lack of a wrist plate avoided key claims in the Corliss patents.

In 1857 the company was renamed for the last time to Corliss Steam Engine Company. By 1864 Corliss bought out his partners and was the sole owner of the company. In 1900 the Corliss Steam Engine Company was purchased by the International Power Company. In 1905 it was purchased by the American and British Manufacturing Company. In 1925 the company merged into Franklin Machine Company. By then Franklin Machine Company was already owned by the William A. Harris Steam Engine Company.

By 1859, all of the key features of what we now know as the Corliss engine were in place. Patents granted to Corliss and others incorporated rotary valves and crank shafts in-line with the cylinders. See, for example, Corliss' U.S. Patent 24,618, granted July 5, 1859.[15] Competing inventors worked hard to invent alternatives to Corliss' mechanisms; they generally avoided Corlis's use of a wrist plate and adopted alternative releasing mechanisms for the steam valves, as in Jamieson's U.S. Patent 19,640, granted March 16, 1858.[16]

Corliss' 1849 patent expired in 1870; the term of this patent had been extended by U.S. Patent reissue 200 on May 13, 1851, and U.S. Patent reissues 758 and 763 on July 12, 1859. B. Hick and Son were first to introduce the Corliss engine into the United Kingdom about 1864. After 1870, numerous other companies began to manufacture Corliss engines. Among them, the William A. Harris Steam Engine Company,[17] the Worthington Pump and Machinery Company,[18] and Allis-Chalmers.[19] In general, these machines were referred to as Corliss engines regardless of who made them.

Centennial Engine

The Corliss Centennial Engine was an all-inclusive, specially built rotative beam engine that powered virtually all of the exhibits at the United States Centennial Exhibition in Philadelphia in 1876 through shafts totaling over a mile in length. Switched on by President Ulysses S. Grant and Emperor Pedro II of Brazil, the engine was in public view for the duration of the fair.

The engine was configured as two cylinders side by side. Each cylinder was bored to 44 inches (112 cm) with a stroke of 10 feet (3.0 m). The Centennial Engine was 45 feet (14 m) tall, had a flywheel 30 feet (9.1 m) in diameter, and produced 1,400 horsepower (1,000 kW). After the fair it was disassembled and shipped back to Corliss's plant in Providence. Seven years later it was sold and powered a Chicago factory owned by George Pullman until 1910,[20] when it was sold as scrap.[21]

This engine became a cultural icon, so much so that to many modern historians the term Corliss Engine (or Corliss Steam Engine) refers to this specific engine and not to the broad class of engines fitted with Corliss valve gear.[22]

List of operational engines

The 1903 Burnley Ironworks Corliss mill engine in action at the Science Museum, London, England, UK.
Location Date of manufacture Date of installation Horsepower RPM Citation
Albert City Threshermen & Collector Show ca. 1920 Unknown 125 120 [23]
Amador Sawmill 1904 2007 60 100 [24]
Antique Gas and Steam Engine Museum 1911 1978 Unknown 80 [25]
Antique Gas and Steam Engine Museum 1900 1986 Unknown Unknown [26]
Arts et Metiers school of engineering of Lille 1900 1900 75 60
Bancroft Shed 1920 1920 600 68
Bolton Steam Museum 1902 1992 180 75 [27]
Bolton Steam Museum 1914 1995 250 Unknown [28]
Bratch Pumping Station 1894 or 1895 1895 or 1896 Unknown 24 [29]
Coldharbour Mill 1910 Unknown 300 Unknown [30]
Connecticut Antique Machinery Association 1910 2008 100 Unknown [31]
Denton Farm Park 1905 Unknown 350 Unknown [32]
Distillerie Dillon 1922 Unknown Unknown Unknown [33]
Ellenroad Ring Mill 1892 Unknown 2650 59 [34]
Gladstone Pottery Museum Unknown 1925 Unknown Unknown
Glenn Beedy Museum of Agriculture & Industry 1923 1992 100 100 [35]
Grand Rapids Public Museum 1905 Unknown Unknown Unknown [36]
Glenwood Resource Center 1907 Dec 19, 1907 Unknown 120
Hesston Steam Museum Unknown Unknown Unknown Unknown [37]
Hook Norton Brewery Unknown 1899 25 Unknown [38]
Markham Grange Steam Museum 1909 1998 700 80 [39]
Mill Meece Pumping Station Unknown Unknown Unknown Unknown [40]
Mississippi Industrial Heritage Museum 1905 2008 Unknown Unknown [41]
Museo de la Caña de Azucar - Hacienda Piedechinche Unknown 1950 Unknown Unknown [42]
National Museum of Industrial History 1913 2015 400 42 [53]
New England Wireless and Steam Museum 1892 1978 150 80 [43]
New England Wireless and Steam Museum 1892 1977 150 80 [44]
New England Wireless and Steam Museum 1911 1969 150 80 [45]
Nittany Antique Machinery Association 150
Old Thresher's Reunion Heritage Museum Unknown Unknown 750 36 [46]
Old Thresher's Reunion Heritage Museum 1920 Unknown 600 150 [46]
Old Thresher's Reunion Heritage Museum 1903 Unknown 125 110 [46]
Old Thresher's Reunion Heritage Museum Unknown Unknown Unknown Unknown [46]
Old Thresher's Reunion Heritage Museum Unknown Unknown Unknown Unknown [46]
Owls Head Transportation Museum ca. 1895 Unknown 600 Unknown [47]
Pawnee County Fairgrounds 1912 Unknown Unknown 150 [48][49]
Queen Street Mill 1895 1895 500 68
Saraya Sugar Factory Unknown 1925 Unknown Unknown [50]
Science Museum, London: Burnley Ironworks Engine 1903 1903 700 76
Stephenson County Antique Engine Club of Freeport, Illinois 1914 1989 1500 45 [51]
The Henry Ford 1859 Unknown 500 70 [52]
The Steam Museum 1900 1986 100 90 [53]
Tokomaru Steam Museum 1916 1976 335 60 [54]
Trencherfield Mill 1907 1907 2500 68
Western Museum of Mining & Industry 1895 Unknown 500 100 [55]

Notable people

See also


  1. ^ Rosenberg; Trajtenberg (March 2004). "A General Purpose Technology at Work". The Journal of Economic History. 64 (1): 75.
  2. ^ Diana Muir (2000). Reflections in Bullough's Pond. University Press of New England. p. 173.
  3. ^ Clark, Daniel K. (1891). The Steam Engine. Vol. Half-vol.3. London: Blackie & Son. p. 39.
  4. ^ Inglis, William (1868). "On the Corliss expansion valve-gear for stationary engines". Proceedings of the Institution of Mechanical Engineers. 19: 177–194 and plates 88 to 97. doi:10.1243/PIME_PROC_1868_019_017_02.
  5. ^ US 6162A, Corliss, George H., "Cut-off and working the valves of steam engines", published 1849-03-10 
  6. ^ Benett, Stuart (1986). A History of Control Engineering 1800-1930. Institution of Engineering and Technology. ISBN 978-0-86341-047-5.
  7. ^ Thompson, Ross (2009). Structures of Change in the Mechanical Age: Technological Invention in the United States 1790-1865. Baltimore, MD: The Johns Hopkins University Press. ISBN 978-0-8018-9141-0.
  8. ^ US 8253A, Corliss, George H., "Cut-off gear", published 1851-07-29 
  9. ^ Harvey-Bailey, Alec; Piggott, Dave (1993). The Merlin 100 series. Rolls-Royce Heritage Trust. ISBN 1-872922-04-X.
  10. ^ Norman, W. (1919). Barring diagrams. Henley Publishing. Retrieved 6 December 2011.
  11. ^ The crowbar for barring the engines is visible in this photo from the Saraya Sugar Factory
  12. ^ "About Us". Straffan Steam Museum. Archived from the original on 2008-09-07. See section "More about the stationary engines", subsection Single Cylinder MILL Engine, Instructions To Start Engine by Sidney J. Frazer.
  13. ^ Valve manipulation is shown in this photo from the New England Wireless & Steam Museum
  14. ^ Walter S. Hutton, The Practical Engineer's Handbook, Crosby, Lockwood and Son, London, 1892, pages 408 and 410
  15. ^ US 24618, Corliss, George H., "Steam-engine", published 1859-07-05 
  16. ^ US 19640, Jamieson, Thomas S., "Improved mode of operating valves in steam-engines", published 1858-03-16 
  17. ^ Michael Thompson (April 18, 2016). "William A. Harris Steam Engine Co". New England Wireless & Steam Museum. Retrieved 16 October 2017.
  18. ^ "Worthington Horizontal Cross-compound Pumping Engine" (PDF). Archived from the original (PDF) on 2011-08-12. Retrieved 16 October 2017.
  19. ^ "A Jacksonville, Florida Historic Mechanical Engineering Landmark" (PDF). Archived from the original (PDF) on 2012-03-14. Retrieved 16 October 2017.
  20. ^ Michael Thompson (January 13, 2010). "Corliss Centennial Engine". New England Wireless & Steam Museum. Retrieved 16 October 2017.
  21. ^ "Some Engines!". Smithsonian Institution. Archived from the original on 2010-06-07. Retrieved 2009-11-14.
  22. ^ Kasson, John F. (1999). Civilizing the Machine: Technology and Republican Values in America. Macmillan. pp. 162–167. The Corliss engine at the Centennial exhibition is discussed entirely as a cultural icon.
  23. ^ Vossler, Bill (October 2017). "The Allis-Chalmers Corliss Steam Engine". Retrieved 16 October 2017.
  24. ^ "History of the Amador Sawmill". Amador Sawmill. Archived from the original on 22 March 2013. Retrieved 6 September 2012.
  25. ^ "Antique Gas and Steam Engine Museum: Allis-Chalmers Corliss Engine". Antique Gas & Steam Engine Museum. Archived from the original on 19 April 2005. Retrieved 6 September 2012.
  26. ^ "Antique Gas and Steam Engine Museum: Vilter Corliss Engine and Ammonia Refrigeration Compressor". Antique Gas & Steam Engine Museum. Archived from the original on 16 February 2012. Retrieved 6 September 2012.
  27. ^ "Wasp Mill Tandem Compound". The Northern Mill Engine Society. Retrieved 6 September 2012.
  28. ^ "Diamond Rope Works". The Northern Mill Engine Society. Archived from the original on 7 February 2012. Retrieved 6 September 2012.
  29. ^ "Bratch Pumping Station: The engines". Bratch Pumping Station. Retrieved 6 September 2012.
  30. ^ "Old Engine House: other museums". Old Engine House. Archived from the original on 13 February 2012. Retrieved 6 September 2012.
  31. ^ "Noble T. Greene Steam Engine". Connecticut Antique Machinery Association.
  32. ^ "Bates-Corliss Engine - Picture of Denton Farm Park - Tripadvisor".
  33. ^ "Residual Steam in Guadeloupe and Martinique, 2012". The International Steam Pages. Archived from the original on 28 March 2013. Retrieved 6 September 2012.
  34. ^ "Victoria & Alexanda - The Worlds largest working mill steam engines". Ellenroad Engine House. Archived from the original on 15 October 2020. Retrieved 16 October 2017.
  35. ^ "Glenn Beedy Museum of Agriculture & Industry". Rock River Thresheree. Archived from the original on 1 September 2012. Retrieved 6 September 2012.
  36. ^ "Artcom Museums Tour:Public Museum of Grand Rapids". Artcom Museums Tour. Retrieved 6 September 2012.
  37. ^ "Hesston Steam Museum". Urban Indiana. Archived from the original on 17 August 2012. Retrieved 6 September 2012.
  38. ^ "Steam at Hook Norton Brewery". Archived from the original on 7 April 2014. Retrieved 6 September 2012.
  39. ^ "Agnes". Markham Grange Steam Museum. Retrieved 6 September 2012.
  40. ^ "Mill Meece Pumping Station: Steam engines". Mill Meece Pumping Station. Archived from the original on 5 August 2012. Retrieved 6 September 2012.
  41. ^ "This weekend: British, steam and barbecues". The Meridian Star. 5 November 2009. Retrieved 6 September 2012.
  42. ^ "Museo de la Caña de Azúcar Hacienda Piedechinche". Alberto. Retrieved 27 November 2014.
  43. ^ "Corliss Steam Engine, 1892". New England Wireless & Steam Museum. Retrieved 16 October 2017.
  44. ^ "Harris Steam Engine, 1892". New England Wireless & Steam Museum. Retrieved 16 October 2017.
  45. ^ "Harris Steam Engine, 1911". New England Wireless & Steam Museum. Retrieved 16 October 2017.
  46. ^ a b c d e Stuart Seedorff. "Midwest Old Thresher's Reunion:Stationary Steam". Retrieved 6 September 2012.
  47. ^ "ca. 1895 Harris-Corliss". Archived from the original on 2011-11-11. Retrieved 15 January 2013.
  48. ^ "National Register of Historic Places - OKLAHOMA (OK), Pawnee County". National Register of Historic Places. Retrieved 6 September 2012.
  49. ^ National Register Digital Assets #79002016
  50. ^ "Real Steam in India 2004 - Saraya Sugar Factory". The International Steam Pages. Retrieved 6 September 2012.
  51. ^ "Cooper Corliss Engine". Stephenson County Antique Engine Club. Retrieved 6 September 2012.
  52. ^ "1859 Corliss Steam Engine". The Henry Ford. Archived from the original on 13 September 2012. Retrieved 6 September 2012.
  53. ^ "About Us". Straffan Steam Museum. Archived from the original on 2008-09-07. See section "More about the stationary engines", subsection Single Cylinder MILL Engine
  54. ^ "The Tokomaru Steam Museum". Peter and Pauline Curtis's Information Service. Retrieved 6 September 2012.
  55. ^ "Mining museum reverberates with realistic settings". The Denver Post. Retrieved 6 September 2012.