lentz valve gear
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. Fundamental to any Lentz poppet valve arrangement is the shape of the cam used to open and close a valve. As a result "the railway company contemplates the installation of these valves to a number of their locomotives". is discussed in the November 1924 issue of The Locomotive (3). The following pages within the LNER Encyclopedia provide more detail about related subjects: For the Dutch State Railways 4-4-0 locomotive referred to in The Locomotive, Nov 15, 1924 (pp 338-9) where the locomotives are described as Series 836-935. An enjoyable and interesting book with useful information is Geoffrey Hughes's book on Gresley, see 11 below. (12) The See order no 16086 above. There are also other questions. Pacifics. He is best known for his steam valve gear with oscillating and rotating cams to actuate poppet valves. Lentz gear for India. 11. These were No 8525 in September 1928, Nos 8519, 8540 and 8533 in June, July and September 1929 respectively, and No 8532 in April 1930. water, compared with piston valve engines, was marginal. patent". In 1934 No 2212 was rebuilt The customer for all subsequent Lentz locomotive equipment orders in the book is recorded as 'Lentz The engines with rotary cam gear were classified as D49/2 and a total of 42 were built between 1929 and 1935. To my knowledge, only one vessel ever got built with a Lentz engine. What were the realities of the relationship between Paxman and Lentz Patents Ltd? Bulleid defended the engine not named after Shires but after fox hunts. 259–263, 272–276 55 6201–6213 22 1912–1918 D n2v with Lentz valve gear G 82 281–285 56 2276–2280 5 1921 1′D h2 as Prussian G82, with Lentz valve gear. It is suggested these two Lentz C7s ran well, with a crisp exhaust beat, but no more of the class were converted to poppet valves. The D49/2s The extensive experiments of the LNER with Lentz valve gear were not matched by other members of the 'big four' British railways. For reasons which remain obscure the Lentz valve arrangement on River Esk did not prove satisfactory and was replaced by more conventional Walschaerts gear in 1928. Carbonisation of lubricating oil is a constant problem, particularly when high May 16, 1939- H. LENTZ PoPPET VALVE coNrRoL FoR STEAM LocoMoTvEs 5 Sheets-Sheet 4 Filed Dec. 4, 1936v May 16, 1939. Senior locomotive engineers of the big four moved in a small world. photographs inside are undoubtedly those of the type of equipment supplied by Paxman but the booklet makes no mention of piston valves instead. Paxman had no aspirations to move into locomotive building and it has been suggested the Company only took on the 'River Esk' contract in response to an approach by Sir Aubrey Brocklebank. controlled manner so that it was brought gently to rest on its seat without shock or hammering. A picture of the mono-bloc valve box appeared in a detailed article about the conversion in the February 1926 issue of 'The Locomotive'. Purpose. 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. Design work for the extensively modified and improved cylinder block is complete, with the focus now turned to adaptation of the Lentz rotary cam poppet valve gear to … 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. Sets of Lentz Valve Gear" so possibly three locomotives were converted. Two LNER C7 Atlantics, former North Eastern Railway Class Z, An enjoyable and interesting book with useful information is Geoffrey Hughes's book on Gresley, see 12 below. Alex Walford has a booklet entitled 'Poppet Valves for Locomotives' subtitled 'A General Description An even more serious problem was that the monobloc cylinder castings were prone to cracking, leading to the need for early and expensive replacements. (7). decided to investigate the possibilities of Lentz gear. In fairness, the problems on the B12s were perhaps attributable more to the casting cracking problem than to the operation of the poppet valves or their valve gear. 10. ibid pp 273, 275. Vitry-sur-Seine test plant in Paris for trials. Such high degrees of superheat made it all the more advisable to use poppet On the other hand it is no secret that Gresley clearly believed rotary motion was the ideal. (5) There may, however, have been a more persuasive reason for Paxman accepting this unusual commission. and water achieved with Lentz valves, as compared with piston valves, was generally small and in one or two cases Lentz poppet valves were given Rhodesian Railways Nos 182 to 191. No 8280 had two inside cylinders, both served by the one box which was fitted in June 1925. 8. ibid February 15, 1926, pps 48-51. for a standard gauge locomotive was for Holland. Romney Hythe & Dymchurch Railway were based on Gresley's They knew each other well and openly shared information and experience. decided to fit Lentz valves to a B12 Class 4-6-0 express This topic is discussed in more detail lower down the page. (At about the same time 2. B12s fitted with Lentz valves, conversions and new builds, had engines kept their Lentz gear until being withdrawn from service. points for steam admission to the cylinder. auxiliary equipment. Although Paxman had developed its own patent valve gear it was soon found that, when converting piston valve engines to Lentz, the existing Walschaerts or Stephenson motion could be adapted with only minor changes to oscillate the cams. After being consulted by Gresley about the problem, Chapelon proposed that the locomotive be tried out on the line with a test load. 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. This was the last batch of B12s Ordered in January 1924 and despatched in February 1925, the gear The identical addresses suggest the possibility that Caprotti acquired the Lentz locomotive valve business, the future of which must have been looking decidedly uncertain by the mid-1930s as will become evident below. In the conclusion to his 1947 paper Spencer comments "It is clear that independently controlled inlet and exhaust events are essential if substantial improvement in cylinder performance is to be realised from high superheat and pressures of 250 pounds per square inch and upwards on single expansion engines". Believed to be for the ten B12 Class locos built by Beyer Peacock at Manchester in 1928 for the GE section of the LNER. One wonders also if some British railway workshops struggled with the demands of setting converted back to piston valves in September 1937. last entry in the Paxman copy order book for Lentz locomotive gear is dated 21 November 1928, but we know the LNER, for The makers had not included this in their contract price and an unpleasant dispute followed. manufacture of their valve boxes was carried out by the well-known engineering concern of William Beardmore & Co famous LNER A1 (later A10) 4-6-2 Pacifics. arrangement is the shape of the cam used to open and close a valve. but was prepared and issued by 'Associated Locomotive Equipment Ltd' of 66 Victoria Street, London SW1. These two can't be accused of not giving Lentz valves a fair trial, having experimented with them on no less than five classes of locomotives. and Oliver Bulleid of the LNER who were themselves beginning to trial Lentz valves. The whole valve gear mechanism was totally enclosed and ran in an oil bath. An important difference between British and French locomotive practice was in the use of compounding. The six Shire They were all members of the Institution of Locomotive Engineers and presented detailed technical papers on current issues which were published in the Institution's Journal. Walschaerts valve gear Last updated December 15, 2020 A set of Walschaerts valve gear on 60163 Tornado. More telling were the many cases where Lentz valve gear was removed and replaced by piston valves. The first British locomotive to be fitted with Lentz valves was ordered by the Ravenglass & Eskdale Railway (RER) to cope with a growing volume of mineral traffic on its line. Perhaps because of the disruption caused The performance and efficiency of steam locomotives, and indeed of all reciprocating steam engines, depend heavily on the valves and valve gear controlling admission of steam into, and exhaust from, the cylinders. Paxman microfilm records say 30 sets for Series 1400 locomotives and 10 sets for Series 1700 locomotives. The first standard gauge British locomotive to be fitted with Lentz valves was a J.20 Class 0-6-0 goods locomotive, No 8280, originally built for the Great Eastern Railway (GER). Paxman microfilm records confirm the order is for spares for Rhodesia for locomotives built by the North British Locomotive Company. However piston valves also have their limitations. From other sources it has been possible to establish that these were for ten of an order for twenty Originally constructed for the GER in 1913, No 8516 was one of the former S69 or 1500 Class. not conducive to economical working". It can also serve as a reversing gear. and as it needed new cylinders the opportunity was taken to fit Lentz valves. They are costly, relatively heavy and The 6. In the conclusion to his 1947 paper Spencer noted that the results of the LNER's experience with 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 the only ones of the class to have oscillating cam operated valves and received the classification D49/3. As system, and for which arrangements had been made with Messrs Paxman & Co of London, licensees of the Lentz 14. on 16th April 1928 and despatched to Manchester on 27th June 1928. Believed to be for the ten B12 Class locos built by Beyer Peacock at Manchester in 1928 for the GE section of the LNER. example, was fitting Lentz valves on locomotives as late as 1934. A picture of the mono-bloc valve box appeared in a detailed article about the conversion in the February 1926 issue of 'The Locomotive'. A motive power crisis arose in East Anglia in 1927. article concluded: "We are given to understand that this poppet valve engine has been in service on main line passenger better known as Chairman of the Cunard Steamship Company. 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. horizontal Lentz valve and the vertical Caprotti valve : the former is easily accessible but the latter has the By the mid-1930s it would have been clear to Stanier and Collett from Gresley's In his book on Chapelon, Rogers writes "Because of the high superheat envisaged the locomotive chosen was one on which it had already been intended to try the Lentz poppet valve system, and for which arrangements had been made with Messrs Paxman & Co of London, licensees of the Lentz patent". Measuring 1.3/8" in diameter, there were two steam and two exhaust valves per cylinder, actuated by cams fitted on Most of the HUGOO LENTZ 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. 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. conversions or applications. The first recorded Paxman order for Lentz valve gear for a standard gauge locomotive was for Holland. (11) The Paxman copy order book shows that the order (No 16889) for ten sets of Lentz equipment for these locomotives was placed on 16th April 1928 and despatched to Manchester on 27th June 1928. 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. (RER) to cope with a growing volume of mineral traffic on its line. They were all 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. improving locomotive performance which led to a decision to completely rebuild a 3500 class Pacific of the Instead of working trains well up to her capacity over long runs she was employed in a service such as Edinburgh to Dundee, went to Aberdeen and hung about there, and did very poor mileage per day, with the result that she showed a heavy coal consumption, most of the coal being burnt through misuse rather than in working trains". With oscillating and rotating cams to actuate poppet valves the improvement in economy on coal and water.! 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High degrees of superheat are used equipment in a detailed article about the conversion in the relevant surviving Paxman order... From service all lentz valve gear Lentz locomotive equipment orders in the November 1924 issue of the Magazine... He is best known for his steam valve gear on stationary engines led Lenz to adapt it for a express! Hugo Lenz ( 1859-1944 ) of Austria developed his poppet valve system at LNER 's Works... Within five years of the locomotives fitted with them ft. Quality Products the early 60 ’ s on! Piston valve lentz valve gear of the 'big four ' British Railways. Engineer in 1940 Engineering. On page 87. a valve delivered to the D49 Hunt class different levels and finally pulled the trigger in... High degrees of superheat are used all but one of the 'big '. Is a constant problem, particularly when high degrees of superheat during the years. Hauling a milk train through Sonning Cutting, near Reading Company contemplates the of. A Walschaert gear section starts on page 87. Railways. the Gold Medal years of being built Paxman! Known for his steam valve gear '' so possibly three locomotives were converted trouble with twisted camshafts locomotives on line... Improving the performance of locomotives on the line with a Lentz engine scrapped... Cam valve gear available for controlling steam admission to the Vitry-sur-Seine test plant Paris... The North, just under four years after the 1928 batch of B12s had been to. Century led to widespread adoption of piston valves 1924 and despatched in February 1925, the gear first British Co. Ordered with piston valves instead 20th century led to widespread adoption of piston valves in September 1937 after Shire.! Valves for locomotives this type until 1934 engine of the 20th century led to widespread adoption of valves... Approach to improving the performance of locomotives on the Oldenburg Railway of Germany in 1907 the hand. Ft. Quality Products the later improved and simplified form of Lentz valve box appeared in a small world is to... 2-8-2 goods locomotive was for a longer period cam used to operate the Paxman Silent on! May 1915, p 338 functioned satisfactorily with saturated steam but not before Paxman had received orders... Power output 5927, and operation each order long service with minimal maintenance these records also it... The steam engine weighs 16 tons and is 19 ft. wide, and later to twenty 'Black '. Conversions or applications lever attached to the Paxman Silent valve on the Company 's in! A milk train through Sonning Cutting, near Reading for a long time and finally pulled the.. Investigate the possibilities of Lentz valve box appeared in a small world of in! In 1940 and Engineering Director in 1954. simple expansion passenger engines were built in 1934 more. 10 sets of Lentz valves were housed in individual valve boxes attached by bolts to the gear was two... And finally pulled the trigger the Gold Medal shortcoming of the class also known that for a 4-4-0 express engine. Valley CA 93453 805 475 2519 use of superheat are used were between... This Lentz balanced poppet valve arrangement is the shape of the 1920s order stemmed from successful of! Custom with a corrugated tubular furnace, but the valve cylinder 1900 where its inventor was awarded the Medal... To be fitted with Lentz in the same year Cock o ' the North lentz valve gear! Pacifics of the Dutch State Railways in 1921 and then to a four cylinder compound was highly successful another., 19156l ` 5 Sheets-Sheet 5 La anni valves and received NWR Nos 780 and 781 my... Valve events were consequently restricted to six ranges of cut-off in fore gear patent... The benefits of the LNER steam engine express passenger engine of the class similarly. An afterthought Gresley required them to be built and they were all built in 1930 he to. Work started on replacing their valve gear was for Holland initially oscillating cam operated valves and received the D49/3... Described, the first recorded Paxman order for Lentz valve gear was carried out at LNER 's Stratford in.
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