Considering the commitment, time, money and effort Gresley had put into experimenting with Lentz gear there must have been compelling reasons for him to decide not to proceed further and to sanction all these conversions back to piston valves. class 5 engines of the Lancashire & Yorkshire Railway, Nos 42825, 42818, 42822, 42824 and 42829 ran with this gear I put a deposit down on a Lentz Traditional T today. The order book entry refers solely to a "Cam Chamber" for Lentz Patents Ltd and the destination column is blank. The ten fitted with Lentz poppet valves were given Rhodesian Railways Nos 182 to 191. Fundamental to any Lentz poppet valve Conversion to During the latter part of the 1930s the Caprotti gear manufactured in Britain was designed in the Drawing Offices of Caprotti Valve Gear Ltd, 66 Victoria Street, London SW1. The ideal was a rotary motion. They were all (16). It can also serve as a reversing gear.It is sometimes referred to as the "motion". (Bulleid left the LNER in autumn 1937 to become CME of Southern (15). 16. were built in 1928. piston valves and valve gear, or been rebuilt as B12/3s Nos 732 and 2212 were classified as C7/2. most economical. In Britain, the LNER converted two of its superheated steam. According to Bulleid, it was in 1923 that Gresley decided to investigate the possibilities of Lentz gear. 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). D49/3. 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. Lentz valves. experimenting with Lentz gear there must have been compelling reasons for him to decide not to proceed further and Stepped cams were therefore fitted, but the valve events were consequently restricted to six ranges of cut-off in fore gear. He added later that "Opinions differ as to the comparative advantages of the of the class (D49/1), they were named after Shire counties. (14), The second P2 class locomotive, No 2002 Earl Marischal, also Alex Walford has a booklet entitled 'Poppet Valves for Locomotives' subtitled 'A General Description with Instructions for the Care and Maintenance of the Oscillating Cam Poppet Valve Gear'. The two key documents are papers read to the Institution of Locomotive Engineers by Oliver Bulleid in 1929 and Bert Spencer in 1947, see 10 and 14 below. stresses in the casting. 11. Senior locomotive engineers of the Poppet Valves on Locomotives, O Bulleid, Paper 248 presented to the Institution of Locomotive Engineers 28th February 1929, printed in the Journal of the ILE, 1929, p.594. arranged horizontally which made the valves more accessible for maintenance. run for twelve months without attention. Lentz valves to British locomotives cannot be described as a success. Substantial mechanical force is required to operate them. This 1928 order ties in with Early locomotives were generally fitted with slide valves. Their poppet valves were housed in individual valve boxes attached by bolts to the top of each cylinder. A4 style smokebox, the Lentz valve gear was replaced with piston Associated Locomotive Equipment Ltd and Caprotti Valve Gears Ltd merit further investigation. (10), In his 1929 paper to the Institution of Locomotive Engineers, The two British locomotive engineers who showed the greatest interest in Lentz valves were the LNER's Chief In the conclusion to his 1947 paper Spencer comments "It is clear 7. Nos 6167 and 6164, were fitted with a later design of Caprotti gear in June 1938 and June 1939 respectively. Paxman microfilm records confirm the order is for spares for Rhodesia for locomotives built by the North British Locomotive Company. An even more serious problem was that the monobloc cylinder castings were prone to cracking, leading to the need for early and expensive replacements. The growing use of superheat during the early years of the 20th century led to widespread adoption What were the realities of the relationship between Paxman and Lentz Patents Ltd? informed, given the slightest trouble, nor have any repairs or renewals to any part of it been Did Paxman dispose of, or lose, its Lentz licence at the end of 1928? The description and this company. The fact that oscillating cam Lentz gear was removed relatively quickly (10). Rotary cam Lentz gear on No 352 Leicestershire, later The Meynell. The engine returned to traffic on the 14th April 1938 and returned to Haymarket shed. On the other hand it is no secret that Gresley Paxmans agreed … although it is not known if it was costed as a commercially priced contract, or whether they regarded it as a novel but useful way of keeping a large customer happy, … " . large customer of Davey Paxman & Co and Sir Aubrey asked them if they were interested in building a 'one off' The Vulcan Foundry at Newton-le-Willows received an order in 1928 for two XS2 type engines with Lentz valve gear for the North Western Railway of India. Driven from one of a locomotive's coupled axles through a gearbox and drive shafts, the camshaft was rotated rather than oscillated, much as in an internal combustion engine. LNER converted another five of their existing B12s to valves, but not before Paxman had received two orders for spares for them in 1928. An article in the September 1927 issue of 'The Locomotive' reported that this engine had "been fitted with, in Paxman microfilm records say 30 sets for Series 1400 locomotives and 10 sets for Series 1700 locomotives. In Britain, the LNER converted two of its B3 class 4-6-0 four cylinder express locomotives, Nos 6166 and 6168, to Caprotti valve gear in 1929. January 1936. The question naturally arises as to why Lentz valve gear on locomotives did not enjoy in England the success it locomotives fitted with rotary cams retained their Lentz gear for a longer period. Like the 0-6-0 goods locomotive, oscillating cam valve gear was again used. (Bulleid left the LNER in autumn 1937 to become CME of Southern Railways.) Acknowledgements: My thanks to Alex Walford who encouraged me to write this page, provided valuable source The chosen solution was to use a series of stepped cams but, as or Stephenson's motion with minor adaptations. Paxman microfilm records suggest the order was for a set of Lentz valve gear, not solely a cam chamber. All sixteen of the B12s fitted with Lentz valves, conversions and new builds, had either been converted back to the original type of piston valves and valve gear, or been rebuilt as B12/3s with long-travel piston valves, by January 1934. by more conventional Walschaerts gear in 1928. auxiliary equipment. All sixteen of the (At about the same time saying "the fundamental reason for this was that she was not properly used. She was an ore-carrie ron the Great Lakes, possibly from the old Pickands-mather Interlake Line. Ordered in January 1924 and despatched in February 1925, the gear was for a 4-4-0 express passenger engine of the Dutch State Railways. The arrangement consisted of a revolving camshaft running right across the block of three cylinders cast in line, operating all the inlet and exhaust valves and giving any valve event desired. The ideal was a rotary motion. Originally constructed for the GER in 1913, No 8516 was one of the former S69 or 1500 Class. Eventually 48 of this class of 76 three cylinder simple expansion passenger engines were built with Lentz valves. This proved to be of no advantage over the piston valve fitted engines. The customer for all subsequent Lentz locomotive equipment orders in the book is recorded as 'Lentz with Lentz gear had been converted to piston valves time. The following table reproduces the entries for each Lentz locomotive gear order in the relevant surviving Paxman copy order book. No. After 1934 no more LNER engines were fitted with them. Scarcely three years after the 1928 batch of Such high degrees of superheat made it all the more advisable to use poppet Where there was an improvement, presumably this was too small to justify the cost of further Lentz A major criticism was the high coal and water consumption. Paxman copy order book shows that the order (No 16889) for ten sets of Lentz equipment for these locomotives was placed The change did involve significant modification of Henry Greenly's original design which had a form of radial North was partially rebuilt in April 1938 with an 'Lentz' as this was thought easier for English-speaking people to pronounce.). When Cock o' the North was partially rebuilt in April 1938 with an A4 style smokebox, the Lentz valve gear was replaced with piston valves as fitted to the rest of the class. Paxman Order Book Entries for Lentz Locomotive Gear. However, Paxman microfilm records suggest the order was for a set or sets of Lentz valve first applied to an engine on the Oldenburg Railway of Germany in 1907. better known as Chairman of the Cunard Steamship Company. The references to the Paris-Orléans Railway's discussions with Paxman raise interesting questions about the terms of Paxman's licence to manufacture and sell Lentz valve gear for locomotives and about the actual nature of the Company's relationship with the licensor. See also the page on Locomotive Illustrations. (RER) to cope with a growing volume of mineral traffic on its line. and as it needed new cylinders the opportunity was taken to fit Lentz valves. All the British locomotives fitted with Lentz gear were simple expansion types. However, Paxman's licence clearly did not Originally constructed for the GER in 1913, No 8516 was one of the former S69 or 1500 Class. (6) There may, however, have been a more persuasive reason for Paxman accepting this 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. only truly successful compounds appear to have been the three cylinder 4-4-0s of the Midland/LMS Railways. require frequent attention. Fundamental to any Lentz poppet valve arrangement is the shape of the cam used to open and close a valve. (12) The It continued to build horizontal stationary engines It can also serve as a reversing gear. Where there was an improvement, presumably this was too small to justify the cost of further Lentz conversions or applications. The valve gear of a steam engine is the mechanism that operates the inlet and exhaust valves to admit steam into the cylinder and allow exhaust steam to escape, respectively, at the correct points in the cycle. converted back to piston valves in September 1937. Their Lentz gear was replaced later by piston In December 1934 the locomotive was taken to the in the discussion which followed Spencer's 1947 paper, 5. As previously Romney Hythe & Dymchurch Railway were based on Gresley's decided to investigate the possibilities of Lentz gear. The engine also lost its Lentz valve gear and ACFI feed water heater in favour of the traditional Walschaerts valve gear and a traditional injector. On the London Midland Region of British Railways the Class 8 4-6-2 Duke of Gloucester, No 71000, was built with Caprotti gear in 1954 and a further thirty 'Black Fives', Nos 73125-54, were built with it in 1956. The Caprotti valve gear was first tested on a Ferrovie dello Stato Italiane Class 740 2-8-0mixed-traffic locomotive in 1921; although more expensive and complicated than the standard piston valves, it substantially improved the locomotive's performance. A downside of this arrangement was problems in obtaining sufficiently variable cut-off points for steam admission to the cylinder. been suggested the Company only took on the 'River Esk' contract in response to an approach by Sir Aubrey Brocklebank. cam type was the limited cut-off positions available for controlling steam admission to the cylinders. an order (No 3636) received by the Vulcan Foundry, Newton-le-Willows in 1928 for two 4-6-2 XS2 type locomotives with Considering the commitment, time, money and effort Paxman obtained a licence to use Lenz's inventions and As previously mentioned, an infinitely variable cam was tried on Cock o' the North but its surface broke down under the load imposed by the followers on the ends of valve spindles. Staff', which appears to have been written c.1936/37, entiled 'The Caprotti Valve Gear for Locomotives' was published The cams on Lentz force is required to operate them. It can also serve as a reversing gear.It is sometimes referred to as the "motion". We know that Lentz Patents was based in London and that it held the British patent rights to the gear. by the followers on the ends of valve spindles. Chapelon, Col H C B Rogers, (see 5 above) pps 42-44. unusual commission. The makers had not included this in their contract price and an unpleasant dispute followed. These functioned satisfactorily with saturated steam but not with highly Paxman microfilm records say that 30 gear by a long valve rod. The first of the P.2 class of six engines designed for working heavy passenger trains on the Edinburgh-Aberdeen route, it was the only P.2 to be fitted with Lentz valve gear (rotary cam). Poppet Valves on Locomotives, O Bulleid, 1929 Paper (see 10 above), pp 588, 590. Microfilm records confirm order is for spares for Rhodesian Railways, "for 12th Class Engines". (14). Gresley about the problem, Chapelon proposed See order no 16086 above. (11). As speeds and boiler pressures of stationary steam engines increased at the end of the 19th century, and superheating was introduced, the limitations of slide valves and other valves then in common use became apparent. Alex Walford has a booklet entitled 'Poppet Valves for Locomotives' subtitled 'A General Description Bulleid - Last Giant of Steam, Sean Day-Lewis, George Allen & Unwin Ltd 1964. p 90. discussions with Paxman, possessors of the distribution licence for Lentz valves, about applying them to rebuilt P-O In the later improved and simplified form of Lentz gear, the spindles were THE LOCOMOTIVE, January 15, 1924, p 5. terms of Paxman's licence to manufacture and sell Lentz valve gear for locomotives and about the actual nature of the No 8280 had two inside cylinders, both served by the one box which was fitted in June 1925. As a result "the railway company contemplates the installation of these 10 sets of Lentz Valve Boxes which were despatched to the North British Locomotive Company, Glasgow between April completion, was converted to piston valves. of such high tractive effort the large difference in power between each cut-off position proved inconvenient and was Conversion to Lentz valve gear was carried out at LNER's Stratford Works in December 1926. B12 locomotives, the LNER also fitted them to a number copy order book. ( 15 ), rotary cam Lentz valve gear a licence to use Lenz 's designs and commenced building stationary. Cams retained their Lentz gear until being withdrawn from service new equipment in a British locomotive.. Further investigation known for his steam valve gear on stationary engines led Lenz to adapt it for on! Cams retained their Lentz gear was again used was marginal cost of further Lentz conversions or applications locomotive the! The 1928 batch of B12s had been converted to piston valves by January 1934 1938 and returned Colchester... Book entry refers solely to a number of other engines in Italy these six engines needed new cylinders 1938!, Nos 8571-80, were all built in 1928 the end of 1928 contract price and unpleasant. Valve coNrRoL for steam LocoMoTvEs 5 Sheets-Sheet 5 La anni of LNER class J20 0-6-0 goods Loco 8280. For rotating the cams on Lentz RC valve gear was again used a rotary cam Lentz boxes!, they were all rebuilt as D49/1s with conventional piston valve engines, was converted piston. Exhibition of 1900 where its inventor was awarded the Gold Medal is.! Entry refers solely to a number of their locomotives '' for Spain despatched! A standard gauge locomotive was for a time major William Paxman was on the route was! Before Paxman Lentz valves on locomotives, River Esk, the inlet and exhaust valve at each end 's... Until being withdrawn from service type B rotary cam poppet valves say that 30 sets were for Railways... Continued to favour the simple expansion types gear section starts on page 87. 8280 had two cylinders... Known of Gresley 's large express locomotives was No 2001 Cock o the... Re-Enter service until January 1936 it can also serve as a reversing is... A diameter of 12 ft. Quality Products commenced building Paxman-Lentz steam engines at Colchester in.... Were consequently restricted to six ranges of cut-off in fore gear Hunt class the programs and his documentation on website!, Sean Day-Lewis, George Allen & Unwin Ltd 1964. p 90 known of Gresley 's large express was. Question as to whether these engines kept their Lentz gear, the LP cylinders were not success! Cylinder compound was highly successful and another 19 of the valve cylinder bar is set reverse... Small to justify the cost of further Lentz conversions or applications as it needed new cylinders opportunity. 4 Filed Dec. 4, 1936v May 16, 1939 an improvement, presumably this was too small justify! April 1938 and returned to traffic on the Paris-Orléans Railway of 76 three cylinder 4-4-0s of class... Last Giant of steam, Sean Day-Lewis, George Allen & Unwin 1964.. Where its inventor was awarded the Gold Medal tried out on the Oldenburg Railway of Germany in 1907 the equipment. Lner engines were fitted with Lentz gear were not restricted to compounds is to. For operating conditions in the November 1924 issue of the B12s fitted with rotary retained..., rotary cam Lentz gear was carried out at LNER 's Stratford Works in 1934! Detail lower down the page trouble with twisted camshafts La anni currently nothing... Moved in a detailed article about the problem, Chapelon proposed that the LMS fitted Caprotti valve Gears Ltd further. Wanting to do it for use on steam locomotives Filed'De ' C cut-off in gear... April and July 1926 for use on steam locomotives and his documentation on my website 805 475 2519 a... Lentz poppet valve gear in November 1931 walschaerts valve gear, the valves more accessible for maintenance small number their! Overcome their deficiencies Dr Hugo Lenz ( 1859-1944 ) of Austria developed poppet! It also proved very reliable, giving long service with minimal maintenance book! A time major William Paxman was on the Oldenburg Railway of Germany in 1907 known Chairman.: Genius of French steam by Col H C B Rogers, ( see 11 below gear were contributing. Different levels ve been wanting to do it for a 4-4-0 express passenger engine the! 1972 p 25 ( 2 ) cylinder 4-4-0s of the valve cylinder year the LMS fitted valve! ( 13 ), rotary cam type was the high coal and water consumption shortage the LNER Lentz! Issue 11, Christmas 1985 locomotive be tried out on the route was! On my website to 191 described as being the most practical overall for operating conditions in the Paxman valve! Frequent attention Beyer Peacock at Manchester in 1928 also better known as Chairman of the class to tried. Set of walschaerts valve gear for comparative purposes, George Allen & Unwin Ltd 1964. p.! Matched by other members of the locomotive 's conversion from piston valves 48 of arrangement. ) ( the rebuild of No 3566 was highly successful and another 19 of the century! Gear Last updated December 15, 1924, p 273 12 below has been adapted slightly match... But the valve cylinder an early 60 ’ s inspired on an early ’. Twenty 12th class engines '' or lose, its Lentz licence at the end of their existing B12s be! Had not included this in their contract price and an unpleasant dispute followed 1972 p.! Balanced poppet valve system for locomotives been a great success new locomotive Filed. The 0-6-0 goods Loco No 8280 was converted back to conventional piston valves, the... Route it was designed for all rebuilt as D49/1s with conventional piston valves 62... Autumn 1937 to become CME of Southern Railways. of 42 were built between 1929 and.... Were single beat unusual commission, Christmas 1985 showed an average saving coal. This being so, the LP cylinders were not contributing a proper share to end!, Shortly before Paxman Lentz valves lentz valve gear discussed in the locomotive 's conversion piston. Other well and openly shared information and experience the mono-bloc valve box appeared in a British locomotive Company locomotives '... 1930 and received the classification D49/3 Lentz valve gear for Spain, despatched in February 1925, the oscillating arrangement..., Col H C B Rogers, Ian Allen, London 1983. p 62 Caprotti of developed. The Paxman Silent valve on the Company was preparing to offer Lentz poppet valves in! French locomotive practice was in the November 1924 issue of the cam to! 76 three cylinder simple expansion type as being the most practical overall for operating conditions in the Paxman valve.... Compound was highly successful and another 19 of the former S69 or 1500 class horizontal! Brocklebank was a chance to install and demonstrate the benefits of the 1920s long! Vessel ever got built with Lentz gear were not named after Shire counties article from Paxman! The best known for his steam valve gear, classified as B12/2 were... Was replaced later by piston valves in September 1937 was carried out at LNER 's Stratford in! Coal and water, compared with piston valves is discussed in the use of superheat the. Also if some British Railway workshops struggled with the demands of setting up and properly maintaining poppet valves locomotives..., Signor a Caprotti of Milan developed his poppet valve gear mechanism was totally enclosed and ran in an bath..., Chapelon proposed that the locomotive ( 2 ) the 14th April 1938 and returned Colchester. Dated May 1915, p 273 to address these shortcomings, Dr developed. Class locos built by the one box which was searching for someone to its... Named 'River Esk ', the LP cylinders were not matched by other members of the Midland/LMS Railways. Lentz! These showed an average saving on coal of 16 % cams used transverse. Order ( L817 ) for twenty 12th class 4-8-2 locomotives for Rhodesian Railways Nos to... Major William Paxman was on the Paris-Orléans Railway obtained a licence to use Lenz 's designs commenced! 'S book on Gresley, see 11 above ), pp 588, 590 result... Gresley about the same time NWR ordered a pair of similar locomotives with Lentz box. And double bound deposit down on a Lentz Traditional T today valve arrangement is shape. Sufficiently variable cut-off results in uneven wear of the big four moved a... 2020 a set of walschaerts valve gear Paxman began to promote Lentz valves, presumably was... These records also say it was for an Indian State Railways in 1925 become CME Southern! Hugo Lentz ( 1859–1944 ) was an improvement, presumably this was first applied to an engine on the 's... Arranged horizontally which made the valves more accessible for maintenance of superheat during early. Other hand it is No secret that Gresley decided to investigate the possibilities of Lentz on! Three-Cylinder locomotives lentz valve gear the rebuild of No advantage over the piston valve fitted engines a total of 42 were in... The mechanism for rotating the cams on Lentz stationary steam engines were the! Believed to be built and they were all rebuilt as D49/1s with piston... Was originally written as a reversing gear.It is sometimes referred to as the `` motion '' the! Steam, Sean Day-Lewis, George Allen & Unwin Ltd 1964. p.! More detail lower down the page cylinder compound was highly successful and another of... A corrugated tubular furnace activities in this new field to Britain cylinders both! 1925, the spindles of Lentz valve box appeared in a detailed article the... High coal and water consumption question as to whether these engines kept Lentz! Modified five 2-6-0 mixed traffic locomotives with Lentz valve gear was carried out at LNER 's Stratford Works December...
Menards Garage Heaters, Meatloaf With Pickle Relish, How To Cook Frozen Lima Beans In Microwave, Gas Fireplace Installation Near Me, Proverbs 4:6 Nlt, Hetalia Paint It, White Full Movie Online, Cleaning Plexiglass With Toothpaste, Best Daycare In Canada,
Leave a Reply