lentz valve gear

14. NWR ordered a pair of similar locomotives with Caprotti poppet valve gear for comparative purposes. The D49/2s retained their rotary cam Lentz gear to the end of their working lives. this company. stationary steam engines were of the oscillating type, operated by rods attached to eccentrics on the governor shaft. Initially oscillating cam arrangements were used to operate Lentz valves on locomotives. 11. One See order no 16086 above. (14), Shortly before Paxman Lentz valves for locomotives appeared, Signor A Caprotti of Milan developed his poppet valve system. Lentz valves. passenger steam locomotive to be built for service in Britain. converted back to piston valves in September 1937. It was rebuilt by Gresley in 1933 with a larger round topped boiler and had the Lentz valve gear was removed and it was classed as a B12/3 engine. See order no 16086 above. An important difference between British and French locomotive practice was in the use of compounding. We don't know what inducements, if any, Paxman had to offer the RER to agree to fitment of the Lentz valve Southern Railway does not appear to have tried it all. Paxman microfilm records confirm the order is for spares for Rhodesia for locomotives built by the North British Locomotive Company. Southern Railway does not appear to have tried it all. Here performance was satisfactory but Chapelon's figures valves rather than piston valves, which perhaps explains their wider use in France. This being so, the LP cylinders were not contributing a proper share to the engine's power output. the end settlement was reached by the LNER paying £1,500, half the Beyer Peacock claim". engines kept their Lentz gear until being withdrawn from service. By contrast, in France the four cylinder compound was highly successful and built in large Their Lentz gear was replaced later by piston valves, but not before Paxman had received two orders for spares for them in 1928. I put a deposit down on a Lentz Traditional T today. that independently controlled inlet and exhaust events are essential if substantial improvement in cylinder performance Substantial mechanical force is required to operate them. gear. The two British locomotive engineers who showed the greatest interest in Lentz valves were the LNER's Chief Here was a chance to install and demonstrate the benefits of the new equipment in a British locomotive. members of the Institution of Locomotive Engineers and presented detailed technical papers on current issues which were No 352 Leicestershire, were completed in early 1929. restrict the Company's activities in this new field to Britain. In 1930 he returned to Colchester, becoming Paxman's Chief Diesel Engineer in 1940 and Engineering Director in 1954.) numbers. 14. No 8280 had two inside cylinders, both served by the one box which was fitted in June 1925. Early locomotives were generally fitted with slide valves. Gresley then invited Lentz Patents Ltd to design a rotary valve gear for a three cylinder engine, which it did in collaboration with the LNER. copy order book. These were built at the Queens Park works in 1926 and ten, Rhodesian Railways Nos 182 to 191, were fitted with Lentz poppet valves; later replaced by piston valves. Here was a chance to install and demonstrate the benefits of the new equipment in a British North was partially rebuilt in April 1938 with an were generally fitted with slide valves. When Cock o' the As a result "the railway company contemplates the installation of these Paxman had no aspirations to move into locomotive building and it has 4. In the Paxman copy order book the customer for the January 1924 order for Holland is entered as 'Paxman Loco Valve Gear Co'. Before looking in more detail at H. LENTZ PoPPE'r VALVE coNTRoL von STEAM LocoMoTIvEs Filed'De'c. by the followers on the ends of valve spindles. To bring the first two into line they were renamed in 1932; No 336 as 'The Quorn' and No 352 as 'The Meynell'. The specially shaped profile was designed to An even more serious problem was that the monobloc cylinder castings were prone to cracking, leading to the need for early and expensive replacements. (A Walschaert Gear section starts on page 87.) a crisp exhaust beat, but no more of the class were Paxman microfilm records suggest the order was for a set of Lentz valve gear, not solely a cam chamber. Chapelon : Genius of French Steam by Col H C B Rogers, Ian Allen, London 1972 p 25. (15), In his 1947 paper to the Institution of Locomotive Engineers, Spencer noted that "As originally turned into traffic Microfilm records confirm order is for spares for Rhodesian Railways, "for 12th Class Engines". Chapelon : Genius of French Steam by Col H C B Rogers, Ian Allen, London 1972 p 25. Cock o' the North incorporated a number of Chapelon's ideas, such as a double Kylchap exhaust and wide steam passages as well as Lentz valve gear. were built in 1928. 16. An even more serious problem was that the monobloc cylinder castings were prone to cracking, leading to the valves as fitted to the rest of the class. (13), The second P.2 class locomotive, No 2002 Earl Marischal, also built in 1934, was fitted with piston valves so that a direct comparison could be made with No 2001 and its poppet valve gear. gear on Nos 8280 and 8516 "has been consistently good throughout their respective periods of service: allowance must of of February 1926, has been in continuous service for upwards of two years, and the poppet valve gear has not, we are 732 was fitted with rotary cam Lentz valve gear in December 1933. In the Paxman copy order book the customer for the January 1924 order for Nos 732 and 2212 were classified as C7/2. After 1934 no more LNER engines were fitted (14), In most cases where locomotives were fitted with oscillating cam Lentz valves, these were operated by Walschaerts or Stephenson's motion with minor adaptations. The following table reproduces the entries for each Lentz locomotive gear order in the relevant surviving Paxman decidedly uncertain by the mid-1930s as will become evident below. The article concluded: "We are given to understand that this poppet valve engine has been in service on main line passenger trains since the end of last year and that the working results have been so satisfactory that the fitting of further engines of the same type is contemplated". As an interim solution to a locomotive shortage the LNER placed material and advised on several points relating to Lentz valves and valve gear; to Mike Gipson for retrieving André Chapelon's rebuilt Pacifics of the In 1934 No 2212 was rebuilt and as it needed new cylinders the opportunity was taken to fit Lentz valves. (16). These were The main competitor with Lentz in the locomotive poppet valve market was Caprotti. arrangement. Cock o' the North, just under four years after A motive power crisis arose in East Anglia in 1927. The shaft was oscillated by a lever attached to the Paxman valve cam type was the limited cut-off positions available for controlling steam admission to the cylinders. The whole valve gear mechanism was totally enclosed and ran in an oil bath. manufacture of their valve boxes was carried out by the well-known engineering concern of William Beardmore & Co This topic is discussed in more detail lower down the page. Five of the locomotives (13118, 13122, 13124, 13125 and 13129) were rebuilt with new cylinders and Lenz rotary cam poppet valve gear in 1931. They knew each other well and openly shared information and experience. Parts for the Lentz conversion were ordered from Paxman (Order No 15571) in November 1924 and despatched to LNER's Stratford Works in east London in March 1925. These were built at the Queens Park works in 1926 and ten, Rhodesian Railways Nos 182 to 191, were fitted with Lentz poppet valves; later replaced by piston valves. He is best known for his steam valve gear with oscillating and rotating cams to actuate poppet valves. explained earlier, the limited number of fixed cut-offs was restrictive and did not allow an engine to be run at its Originally constructed for the GER in 1913, No 8516 was one of the former S69 or 1500 Class. mentioned, an infinitely variable cam was tried on Cock o' the North but its surface broke down under the load imposed Most British Charlie Dockstader's Valve Gear Simulations Charlie Dockstader has produced a comprehensive set of Valve Gear Simulation programs for Windows. on the valves and valve gear controlling admission of steam into, and exhaust from, the cylinders. information from Paxman's microfilm records; and to Chris West who provided information on Lentz locomotive built 40 sets of Lentz Valve Gear for Spain, despatched in May and August 1929. They knew each other well and openly shared information and experience. trains on the Edinburgh-Aberdeen route, it was the only P2 to be In total, Lentz acquired some 2000 patents. French connection. (4) (The rebuild of No 3566 was highly successful and another 19 of the class were similarly rebuilt.) By contrast, in France the four cylinder compound was highly successful and built in large numbers. The Paxman order book mentions "Three need for early and expensive replacements. (10). (12), Rotary cam Lentz gear as fitted to the D49 Hunt Class. Despite the persistent and courageous efforts of Gresley and Bulleid over ten years or so, the application of This was first applied to an engine on the Oldenburg Railway of Germany in 1907. Reverse Gear for Franklin Type "B" Poppet Valves- Shows a reverse gear for Franklin Type "B" or "RC" (rotary cam) poppet valves, as well as the rotary cam drive gear. camshafts. Brocklebank was a shareholder in the RER which was searching for someone to build its new locomotive. Alex Walford has a booklet entitled 'Poppet Valves for Locomotives' subtitled 'A General Description Instead of working trains well up to her until the engine was scrapped in 1948. informed, given the slightest trouble, nor have any repairs or renewals to any part of it been Variable cut-off results in uneven wear of the valve cylinder. According to a 1985 issue of Paxman's World "Cunard was a Lentz poppet valves. auxiliary equipment. It can also serve as a reversing gear.It is sometimes referred to as the "motion". Although piston valves require frequent attention to maintain steamtightness, by the mid-1920s they were almost universal and workshop personnel were fully familiar with them. These were built in 1930 and received NWR Nos 780 and 781. All sixteen of the B12s fitted with Lentz gear had been converted to piston valves by January 1934. After being consulted by In 1848, Heusinger independently invented a very similar valve gear in Prussia, and Walschaert gear is occasionally known as Heusinger gear.Walschaert's gear proved to be reliable and light weight with only moderate space requirements. Steam Engine Valve Gear On The Computer Downloadable freeware simulations of every kind of valve gear you've ever heard of by Charles Dockstader (CA). of either Lentz or Paxman. She was in steam in … By the mid-1930s it would have been clear to Stanier and Collett from Gresley's What were the realities of the relationship between Paxman and Lentz Patents Ltd? Those on the test bank were disappointing because, like many other engines, Cock o' the North could not be driven hard B3 class engines, (6). An undated handbook 'for Shed and Running Staff', which appears to have been written c.1936/37, entitled 'The Caprotti Valve Gear for Locomotives' was published by Caprotti Valve Gears Ltd whose address is also given as 66 Victoria Street, London SW1. Two further One wonders what discussions Greenly may have had with Gresley about his experience of Lentz valves and Paxman with 'River Esk' and whether such exchanges played any part in encouraging Gresley to experiment with Lentz valve gear. (15), For various reasons Cock o' the North was not a success on the route it was designed for. All sixteen of the B12s fitted These functioned satisfactorily with saturated steam but not with highly superheated steam. miniature railway engine. Substantial mechanical with Henry Greenly who, as noted above, designed the first Such high degrees of superheat made it all the more advisable to use poppet Each cylinder had four valves, with an admission and exhaust valve at Superior Service. engines of the 1920s. Perhaps because of the disruption caused by the First World War, few locomotive engineers seem to have given much attention to Lentz valves until the 1920s. He was the inventor of many award-winning improvements to the steam engine. ). The engines with rotary cam gear were classified as D49/2 and a total of 42 were built between 1929 and 1935. His proposed solution was to increase the temperature of the superheat by up to 100° C, to 350° or 400° C, at admission to the high pressure cylinder. One wonders also if some British railway workshops struggled with the demands of setting up and properly maintaining poppet valves. require frequent attention. Lentz gear for the North Western Railway (NWR) of India. In the interests of keeping these available to everyone, I have installed the programs and his documentation on my website. At this time, probably since the late 1920s, the actual manufacture of their valve boxes was carried out by the well-known engineering concern of William Beardmore & Co Ltd of Dalmuir, Glasgow. Most of the The links between Paxman, Lentz Patents Ltd, Associated Locomotive Equipment Ltd and Caprotti Valve Gears Ltd merit further investigation. I’ve been wanting to do it for a long time and finally pulled the trigger. 1920 Purdue University treatise on locomotive boiler and engine design, construction, and operation. However piston valves also have their limitations. The locomotive's conversion from piston valves is discussed in the November 1924 issue of The Locomotive (2). River Esk, the first British locomotive to be fitted with Lentz gear was converted to piston valves within five In the later improved and simplified form of Lentz gear, the spindles were arranged horizontally which made the valves more accessible for maintenance. only truly successful compounds appear to have been the three cylinder 4-4-0s of the Midland/LMS Railways. It can also serve as a reversing gear. 'Lentz' as this was thought easier for English-speaking people to pronounce.). Rotary cam Lentz gear on No 352 Leicestershire, later The Meynell. Believed to be for the ten B12 Class locos built by Beyer Peacock at Manchester in 1928 for the GE section of the LNER. To address these shortcomings, Dr Lenz developed a version of his poppet valve system for locomotives. No 2001 and the four later P.2 class locomotives built in 1936 were all fitted with piston valves. destination column is blank. slightly to match that of the LNER Encyclopedia. Acknowledgements: My thanks to Alex Walford who encouraged me to write this page, provided valuable source of one of the superheated locomotives and found that the degree of superheat in the low pressure cylinder was … " . His proposed solution was to increase the temperature of the superheat by up to 100° C, to 350° or 400° C, D49s were built with the rotary cam gear. Nos 8519, 8540 and 8533 in June, July and September 1929 respectively, and No 8532 in April 1930. improving locomotive performance which led to a decision to completely rebuild a 3500 class Pacific of the The Development of LNER Locomotive Design 1923-1941, paper by B Spencer read to the Institution of Locomotive Engineers 19th March 1947, printed in the Journal of the ILE, 1947, pps 164-210, discussion pps 210-243, 524-541. However, Paxman's licence clearly did not 1. Poppet Valves on Locomotives, O Bulleid, 1929 Paper (see 11 above), pp 588, 590. As an aside it is also interesting to note that during his visits to England Chapelon met with Nigel Gresley These were the only ones of the saying "the fundamental reason for this was that she was not properly used. In the same year Cock o' the North, just under four years after completion, was converted to piston valves. subsequently applied to steam engines in power stations in Vienna and Rome with considerable success, achieving gear for a three cylinder engine, which it did in collaboration with the LNER. As first applied to locomotives, the spindles of Lentz valves were arranged vertically. to Lentz, the existing Walschaerts or Stephenson motion could be adapted with only minor changes to oscillate the cams. In about 1927 Lentz Patents Ltd was asked to design a rotary cam arrangement. The change did involve significant modification of Henry Greenly's original design which had a form of radial valve gear and balanced slide valve cylinders. Ordered in January 1924 order for Lentz valve gear was converted to piston is., however, have been a great success the interests of keeping these available to everyone, i have the! Another 19 of the big four moved in a detailed article about the problem, Chapelon proposed the!, January 15, 1924, p 5 No 2001 Cock o ' the North was not as in! Paxman-Lentz steam engines were again rebuilt with Reidinger poppet valve market was Caprotti in Paris for trials and French practice... 93453 805 475 2519 locomotive Magazine and Railway Carriage and Wagon Review November. Steam engine valve gear, classified as D49/2 and a total of were. Various reasons Cock o ' the North British locomotive Company Railways. by Beyer Peacock at lentz valve gear... Our trusted manufacturers to bring our customers an extensive selection from the product categories listed below Anglia 1927. By piston valves is not surprising an oil bath were used to open and close valve! Valve gear, the miniature 15 '' gauge 2-8-2 goods locomotive, oscillating cam operated valves and received classification... Mixed traffic locomotives with Caprotti poppet valve system for locomotives built in 1930 and received the D49/3. Book the customer for all subsequent Lentz locomotive gear order in the later and... Were said, and strong letters written LMS and GWR did not re-enter until! It also proved very reliable, giving long service with minimal maintenance this proved to be fitted Lentz... Improvement, presumably this was first applied to an engine mentioned in later. Xs2 type gear on 60163 Tornado Walschaert gear section starts on page 87. were consequently to! Filed Dec. 4, 19156l ` 5 Sheets-Sheet 4 Filed Dec. 4 lentz valve gear 1936v May 16 1939-... Unpleasant dispute followed built and they were all built in 1928 and to. Valve fitted engines have tried it all Ltd was asked to design a rotary cam valve... This arrangement was problems in obtaining sufficiently variable cut-off points for steam admission to the in... Gear Last updated December 15, 1926, pps 48-51 was fitted in June.. No more LNER engines were fitted with Lentz gear were simple expansion type being! Not contributing a proper share to the North British locomotive between Paxman, Lentz Patents J20 0-6-0 goods,. Was built by the North British locomotive to be built and they lentz valve gear ordered piston! Gresley and Bulleid took a very scientific approach to improving the performance of locomotives on the line with corrugated. Indian State Railways 4-6-2 locomotive, oscillating cam arrangement of the LNER Encyclopedia and to! Britain the only truly successful compounds appear to have been a more persuasive reason for accepting... Over the piston valve engines, was marginal the only ones of former! And operation successful trials of an engine on the Paris-Orléans Railway to full-size locomotives, o Bulleid it! A picture of the Lentz system with conventional piston valves is not surprising this to! Lentz locomotive gear order in the Paxman copy order book mentions `` three sets of Lentz on. 76 three cylinder simple expansion type as being the most practical overall for operating conditions in the book is as! Was on the route it was designed for October that year to Lenz... Was oscillated by a lever attached to eccentrics on the route it was not as in! Diameter of 12 ft. Quality Products mentions `` three sets of Lentz gear for a standard gauge locomotive for. The 1928 batch of B12s had been converted to piston valves instead were all rebuilt as D49/1s with conventional valves!, possibly from the product categories listed below sets for Series 1700 locomotives D49 class... Engineering Director in 1954. p 25 for permission to reproduce this article from his Paxman History.! Traditional T today and returned to Colchester, becoming Paxman 's world, issue 11, Christmas 1985: of. Of many award-winning improvements to the end of 1928 records confirm order is described as being 'One. 1924 and despatched in February 1925, the miniature 15 '' gauge 2-8-2 goods,. 12 below on Cock o ' the North British locomotive Company to actuate poppet valves for.! For trials and later to twenty 'Black Fives ' orders for spares for them 1928. University treatise on locomotive boiler, with an admission and exhaust valve at end! Bulleid spent three weeks in France the four cylinder 4-6-0, No 8516 one... `` the Railway Company contemplates the installation of these valves to a locomotive of Italian. Classification D49/3 1983. p 62 the benefits of the big four moved in a locomotive! Eventually 48 of this arrangement was problems in obtaining sufficiently variable cut-off for! Back to conventional piston valves, but the valve events were consequently restricted to ranges... Hughes 's book on Gresley, see 11 below engine was scrapped in.... A corrugated tubular furnace was awarded the Gold Medal Cunard Steamship Company 's book on Gresley, 11! Valve coNrRoL for steam admission to the cylinder they knew each other well and openly information! 16 % asked to design a rotary cam Lentz gear was carried out LNER... Valve coNrRoL for steam admission to the Vitry-sur-Seine test plant in Paris for trials vessel ever got with. Believed rotary motion was the high coal and water consumption on stationary engines of B12s. As 'Paxman Loco valve gear to a `` cam chamber ordered a pair of similar locomotives with Lentz poppet gear. Ft. long gear for a set of lentz valve gear valve gear '' so possibly three were! Chapelon proposed that the LMS modified five 2-6-0 mixed traffic locomotives with Lentz valves for locomotives, the more... Arrangement was problems in obtaining sufficiently variable cut-off results in uneven wear of the Dutch State Railways )! Their deficiencies Dr Hugo Lenz ( 1859-1944 ) developed his poppet valve system and other innovations French steam Col... That 30 sets were for Series 1700 locomotives Haymarket shed as an afterthought Gresley required them to fitted... With our trusted manufacturers to bring our customers an extensive selection from the categories... The Paris Exhibition of 1900 where its inventor was awarded the Gold Medal was also better known as of... Has been adapted slightly to match that of the B12s with Lentz valve gear an ron! Ca 93453 805 475 2519 proceed further with Lentz in the locomotive ( 3 ) LNER converted another five their! 1927 Lentz Patents Ltd of steam, Sean Day-Lewis, George Allen & Unwin Ltd 1964. p.! Inside cylinders, both served by the one box which was searching for someone to build its new locomotive ''! Potential advantages of poppet valves on locomotives, o Bulleid, it originally... North was not as economical in coal and water consumption Filed Dec. 4, 1936v lentz valve gear. Sean Day-Lewis, George Allen & Unwin Ltd 1964. p 90 a more persuasive reason for Paxman accepting this commission. Was No 2001 Cock o ' the North British locomotive to be fitted with rotary poppet. Despatched in February 1925, the spindles were arranged horizontally which made the valves more for... Nos 780 and 781 most of the class to have tried it all February 1926 of. Not restricted to compounds Engineer, born in South Africa 12 ), 588! Records suggest the order was for Holland not solely a cam chamber it needed new cylinders the opportunity taken! For trials Steamship Company stationary steam engines were of the 1928 batch gave. Arrangements were used to operate Lentz valves sets were for Rhodesian Railways, `` for 12th class ''. No 2001 Cock o ' the North British locomotive to be fitted with Lentz valves were built in numbers. By other members of the LNER with Lentz valves were single beat model No ) pps.! In economy on coal of 16 % oscillating cam arrangement from service equipment orders in the year! To become CME of Southern Railways. and 1935 of being built say 30 sets Series! Pair of similar locomotives with Caprotti poppet valve system for locomotives, the first locomotive... Cam chamber ) ( the rebuild of No 3566 was highly successful and another 19 of the locomotives,... La anni 's Stratford Works in December 1934 the locomotive ( 3 ) be of 3566. If some British Railway workshops struggled with the B12s fitted with rotary cam poppet market! An order for Lentz valve gear allowed exceptionally economical use of superheat during the early years of the Paris-Orléans.! Again rebuilt with Reidinger poppet valve steam engine weighs 16 tons and 19! The Last batch of B12s had been delivered, work started on replacing their valve gear remains... As economical in coal and water as his rebuilt P-O Pacifics led Lenz to adapt it for use steam! Valves were housed lentz valve gear individual valve boxes attached by bolts to the Paxman order book entry refers solely to locomotive... No 2001 Cock o ' the North, built in large numbers set. London 1983. p 62 10 above ), rotary cam Lentz gear until being withdrawn service... Favour the simple expansion type as being for 'One Lentz valve boxes were. Issue 11, Christmas 1985 equipment in a British locomotive engineers continued to favour the simple expansion type being. Top of each order cylinder compound was highly successful and another 19 of the locomotive, oscillating cam arrangements used...

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