setting stephenson's valve gear

Rotate the wheel/move the loco so the piston is at top dead centre. With the crank pin a few degrees past read dead center, the slide valve begins to open the rear steam port, for the admission of fresh steam, and the front port, for the ejection of used steam through the exhaust port. Next, you will do Slide Valve and Cylinder Adjustments. Once again, there is only one correct position for them. 4767 sho... World Heritage Encyclopedia, the aggregation of the largest online encyclopedias available, and the most definitive collection ever assembled. but I cannot view the essential Images.Iwas wondering if they could be Preparation. You will find the pencil marks very handy. Another variation derived from the Stephenson gear was the Allan straight link motion. Valve gears such as Walschaert's are said to be constant lead valve gears. If your cams are properly spaced 90 degrees apart and you have done everything else right while building it, you should hav enot difficulty in timing it. With the crankpin at apporximately 150 – 160 degrees of rotation, the slide valve should close the rear steam port. to avoid excessive lead when notched up, the gear must be set for negative lead in fullgear. Timing Stevenson Valve Gear can be a real challange, especially when you do it the first time. Move the reverse lever in full forward. 4 cams. Then put rods in the 9 o'clock position, lock down the drivers, reverse lever in full reverse and move the reverse cam until the head covers the back opening in the head. Stephenson valve gear - most common valve gear in the 19th century, normally inside the locomotive frame. Stephenson’s valve gear was extensively used worldwide throughout the 19th century and through the first half of the 20th Century on Great Western Railway 2-cylinder locomotives. Again the pencil marks come in handy. When it comes to valve gear, I don't pretend to be an expert, but I'm presently setting up Stephenson valve gear on the 7 1/4" Dart (inside cylinders) I'm building. This is easily ascertained by measuring from the rail to the footplate on all four corners. #267B in the International Library of Technology. This is called "centering the valve" and is absolutely necessary to be able to properly time the engine. 4.) Put your revers lever in full forward. What I did not realize was the die block was not up the full height in line with the eccentric rod, hence my problem. Also, if the eccentric rods incorporate the small addition in length to satisfy centralising of the leads, Stephenson’s gear can be set for equal leads at any reverser setting instead of achieving this at only one preferred notch. Don Ashton gives several methods of doing this in his excellent book on the gear. Not the simplest solution, but the gear had the distinctive feature of the drive rod having a large mass at the valve gear end, and thus a taper in the reverse direction. Take a soft lead pencil and mark the exact edge of the opening on both the front and back of the valve head. Hello, The Gooch valve motion set for running ahead. Before setting my height of the underside of my boiler, I moved the linkage into what I thought was the upper position. Setting valve line-and-line again, ... FITTED WITH STEPHENSON’S GEAR. This message will no longer be displayed after This will need some extrapolation and a dial indicator. STEPHENSON’S LINK VALVE GEAR – GWR HALL 4-6-0 This kit is designed to accurately produce in 4mm scale a working model of the Stephenson’s link valve gear. What I did not realize was the die block was not up the full height in line with the eccentric rod, hence my problem. This is a Martin Evans design from Model Engineer of an 0-4-2 tank engine. If not use the adjustment screw on the valve rod to center it. Do this on both sides of the engine. With the gear in full forward set the eccentric so that the valve is just cracking the port. JAVASCRIPT IS DISABLED. Contents. Everything to me looked good. (Railway Heritage) ... especially in this context the page on Stephenson's gear. The amount of lead remains constant over the whole range of cut offs that the gear is designed to provide. Valve setting with Stephenson link valve timing on our 7 1/4" Forney locomotive. A unique engine This experimental set of outside Stephenson valve gear was developed with two fly cranks rather than eccentrics to give a maximum travel of about 6½in, the same as the piston valves in the Walschaerts gear engines. The rest of the rotation, through the foward dead center, is performed with the help of steam expansion. Good afternoon, I am looking at ways of creating the preserved Stephensons Valve Gear Black Five 44767 George Stephenson and the Caprotti Standard Five 73129, i am on a budget and my modelling skills aren't great, so i wondered if anyone knew of any easy kit bash options or a cheap and easy conversion kit for either of the above. photos are not showing up on the valve gear page. When it comes to valve gear, I don't pretend to be an expert, but I'm presently setting up Stephenson valve gear on the 7 1/4" Dart (inside cylinders) I'm building. Thank you! This setting information is the same for all Stephenson link valve gear. Take the heads off both cylinders. Similarly, the eccentrics for Stevenson link valve gear can be set once and for all before the axle is even fitted in the loco. The amount of lead remains constant over the whole range of cut offs that the gear is designed to provide. Move the forward eccentric until the valve just barely covers the opening and lock it down. Slide valves largely used in the 19th century; 2. The necessary two harmonic components are conveniently embodied in the eccentrics, whose advance accommodates the lap and lead as well as supplying the necessary travel. Your illustration notes Take a soft lead pencil and mark the exact edge of the opening on both the front and back of the valve head. This experimental set of outside Stephenson valve gear was developed with two fly cranks rather than eccentrics to give a maximum travel of about 6½in, the same as the piston valves in the Walschaerts gear engines. First, you want to set the cams. That is what it feels like as I try to rotate the drive shaft, it feels like the timing is way off in forward gear. The bar moves back and forth, with due care since it appears to bind at the valves. For reasons of practicality two significant deviations from the prototype have been made. This is a Martin Evans design from Model Engineer of an 0-4-2 tank engine. Now the eccentrics can be set. stephensons valve gear etc., eccentric problem. I owned at one time a 3/4" 4-4-0 that had inside Walschaert valve gear. Two for each side, one was a froward and one was reverse. Please advise on how to get the pictures herein. I really need to set it up to operate smoothly but can only find vague instructions. This page was last modified on 11 May 2018, at 15:17. The cost in drawing office time and manufacture of the components must have been considerable for a ‘one off’ and on the eve of nationalisation of the … Tom Stamey wrote the following description for setting Stephenson valve gear on Allen Models locomotives, 20 April 2014. at the very start of a stroke, the valve opens to admit steam from the boiler into that space. The valve gear was adjusted electrically, and the vaves could be set in in open posion for coasting with minimum resistance. http://ibls.org/mediawiki/index.php?title=Setting_Stephenson_Valves&oldid=12347. For reasons of practicality two significant deviations from the prototype have been made. ... especially in this context the page on Stephenson's gear. Would love to get a copy with photos Thank You 316-644-3606 I have a stained glass company for 35 years, I aslso would like to view pictures please. Several types of valves were developed over the years, but most fall within three main catagories: 1. As a live steamer. the GWR stephensons gear as fitted to Firefly produces a large increase in the amount of lead as the gear is notched up from fullgear. The Walschaerts valve gear is an improvement on the earlier Stephenson valve gear in that it enables the engineer to operate the steam engine in a continuous range of settings from maximum economy to maximum power. Just blank with a red X in the left corner. It is named after Robert Stephenson but was invented by his employees. I have a Stephenson setup with no manual and saw your setup but none of the drawings or pictures show on the screen. Poppet valves similar in principle to those used in internal combustion engines. Green cloth w/red cloth backstrip w/gilt spine lettering, marbled end papers, illustrated, three fold-outs. One consequent disadvantage of the Stephenson gear is that it has a tendency to over-compression at the end of the stroke when very short cut-offs are used, and therefore the minimum cut-off cannot be as low as on a locomotive with Walschaerts gear. The necessary two harmonic components are conveniently embodied in the eccentrics, whose advance accommodates the lap and lead as well as supplying the necessary travel. 2. The advance setting of the eccentrics in Stephenson’s gear is directly responsible for the amount of lead steam – the smallest critical dimension on the whole locomotive. I cannot see the pics either. Allan valve gear, a straight-link valve gear. Or, if you have not yet put the boiler on you can time it and see the valve from above. It GREATLY simplifies things if you have one person watching the valve while another is under the engine moving the cams. The difference is that stevension valve gear used 4 eccentrics. I had the opportunity to due the timeing on a 3/4″ and 1-1/2″ scale locomotives. Correct about left, drivers left standing on footplate facing forward, cannot help with valve setting, sorry. The valves on a steam engine control the flow of steam in and out of the cylinders. The valve must be equally located between the front and rear openings in the head. Assuming your adjustment nuts never get loose you won't ever have to do this again. Similarly, the eccentrics for Stevenson link valve gear can be set once and for all before the axle is even fitted in the loco. So there is no hard rule that a inside valve gear has to be type x. Preparation. The use of Stephenson’s gear quickly became widespread, particularly suiting a direct drive to inside cylinders and slide valves common in the 19th century. My loco has 2 reverse cams inside Before setting my height of the underside of my boiler, I moved the linkage into what I thought was the upper position. Take a soft lead pencil and mark the exact edge of the opening on both the front and back of the valve head. The Stephenson valve gear or Stephenson link or shifting link is a simple design of valve gear that was widely used throughout the world for all kinds of steam engines. The use of Stephenson’s gear quickly became widespread, particularly suiting a direct drive to inside cylinders and slide valves common in the 19 th century. I have seen working stevension valve gear on engines. The front valve covers are When the link is fully raised as depicted in the drawing to the left, the eccentric that sets the valve motion for forward engine operation is directly in line with the valve rod (shown in the drawing as the line off to the left). At any setting, the valve gear satisfies the following two conditions: 1. Then, with the reverse lever in neutral move the rods to the position of 12 o'clock. This fine model in the Science Museum, South Kensington, can be operated by the public and clearly shows the application and working principles of the Gooch gear. ... Lead is governed by the valve gear and its setting. Stephenson valve gear: | | | British LMS Stanier Class 5 4-6-0 Locomotive no. Six locomotives, including No 4767, were fitted with double chimneys and electric headlights. and 2 forward cams outside. STEPHENSON’S LINK VALVE GEAR – GWR HALL 4-6-0 This kit is designed to accurately produce in 4mm scale a working model of the Stephenson’s link valve gear. Take some time to make sure you have them squarely on 12. 1. The cams consist 4 individual cams. Take the heads off both cylinders. Don Ashton gives several methods of doing this in his excellent book on the gear. First, you want to set the cams. The pressure of this steam provides the driving fo… How do the reverse cams enter into the illustration ? I’m in the process of restoring broken images. At rear dead center, both steam ports are closed by the slide valve. Take the heads off both cylinders. I really need the pictures for setting up the stephenson gear. At the instant when the space on one side of the piston starts to expand, i.e. Valve gears such as Walschaert's are said to be constant lead valve gears. ! The Stephenson valve gear or Stephenson link or shifting link is a simple design of valve gear that was widely used throughout the world for various kinds of steam engines. 1.) Everything to me looked good. In the past I know that if the links of this type of gear are not positioned right it will not time correctly. With the covers off the valve/steam chest then with the lever/bar centred (mid gear) the valve should just open the ports and it should be symmetrical at top and bottom dead centre respectively. Better to set the eccentrics at full gear so that the valve only just cracks the ports at TDC/BDC and adjust the spindle length or slide position so it is sy… The cams consist 4 individual cams. The slide valve closes both steam ports as in 1. It is essential at the commencement of operations to be certain that the engine is at its correct working height. Attn: Admin. The drivers set on a 7.5″ width track. Valve gears such as Stephenson's for example are variable lead valve gears. HTML tags allowed in your comment:

. Then lock it down. Contains chapters on locomotive valves, the Stephenson valve gear, locomotive management, breakdowns, oil-burning locomotives, the Type D duplex stoker, and locomotive value setting. ... the eccentric rod pivots were set behind the link slot (or below on a vertical engine). The use of Stephenson’s gear quickly became widespread, particularly suiting a direct drive to inside cylinders and slide valves common in the 19th century. Same as the other e-mails. Go to the fireman's side and put the rods at 9 o'clock, lock drivers down, reverse lever in full forward, move the forward cam to where the valve just covers the front opening, and lock it down. Thank you kindly. They can tell you when to stop or to go the other way etc. 2.) You will have to move the engine to do that. The necessary two harmonic components are conveniently embodied in the eccentrics, whose advance accommodates the lap and lead as well as supplying the necessary travel. Download Windows Valve Gear Programs File 10A, 1.57 MB, Version 2.7.3 Download Windows Valve Gear Programs File 10B, 1.26 MB, Version 2.7.3 Download Windows Valve Gear Programs File 10C, 1.25 MB, Version 2.7.3 Download Windows Valve Gear Programs File 10D, 1.28 MB, Version 2.7.3 1. Tom Stamey wrote the following description for setting Stephenson valve gear on Allen Models locomotives, 20 April 2014.. Place the rods on the engineer side of the engine at 3 o'clock taking care to position them properly as close to 3 as possible and lock the drivers down. emailed.This would be most appreciated. It is essential at the commencement of operations to be certain that the engine is at its correct working height. Ian wrote on Yahoo Group: 1. Interestingly, neither Stephenson or Howe ever applied for a patent of the idea. David Bothwell 1: 17/01/2020 17:05:39: 155 forum posts: Thanks for that Baz, a big help, I,ll get to the bottom of the valve setting somehow/some way! Piston valves which superseded slide valves in the 20th century; 3. Can you email them to me? To make a proper trial, Ivatt included the standard Walschaerts valve gear, but for the first time in almost 100 years, one locomotive, No 4767, was fitted with an experimental set of outside Stephenson motion. 8-31-12 10:55 p.m. CDT Tom Stamey wrote the following description for setting Stephenson valve gear on Allen Models locomotives, 20 April 2014.. Re: Setting Stephenson Valve Gear Post by baggo » Tue Nov 22, 2011 10:52 am If you look at 'Stephenson British Outside Admission' in Charlie's software, that gives a direct drive to the valve. Valve gears such as Stephenson's for example are variable lead valve gears. Move the loco half a circumference and the other port should just crack. 3. The reversing shaft goes across the frames and activates both sets of valve gear, (and there is no reach rod on the left hand side of course) but the rock shafts and rock arm assemblies are on both sides of the locomotive and independant of each other. The front valve covers are When the site was transferred, some of the images didn’t follow. IN FORWARD GEAR. These became known respectively as the 'locomotive link' and the 'launch link'. This is easily ascertained by measuring from the rail to the footplate on all four corners. In theory, of course, the valve could be set … 1 Historical background; 2 Applications; 3 Derivatives. 1. The reversing shaft goes across the frames and activates both sets of valve gear, (and there is no reach rod on the left hand side of course) but the rock shafts and rock arm assemblies are on both sides of the locomotive and independant of each other. Understand that moving the reverse cams will slightly affect the forward valve position and vice versa and that you will have to repeat the above steps a couple of more times to get the engine to time as close as possible. It is fitted to 0-4-0WT "Dolgoch", preserved on the Talyllyn Railway. William T. James valve gear 1832, used first by Baltimore and Ohio Railroad, United States. Setting valve line-and-line again, ... FITTED WITH STEPHENSON’S GEAR. Put rods at 3 o'clock, lock down the drivers, reverse lever in full reverse and move reverse cam until the valve covers the back of the opening. The Stephenson valve gear or Stephenson link or shifting link [1] is a simple design of valve gear that was widely used throughout the world for all kinds of steam engine.It is named after Robert Stephenson [2] but was actually invented by his employees. Timing Stevenson Valve Gear can be a real challange, especially when you do it the first time. Iam trying to view the article timing Stevenson Valve Gear it reads well Once again, there is only one correct position for them. I had the opportunity to due the timeing on a 3/4″ and 1-1/2″ scale locomotives. 3.) you add at least one widget to one of the Sidebar Widget Areas using the Appearance → Widgets control panel. Please enable JavaScript on your browser to best view this site. When the reversing lever (Johnson Bar) is in mid gear position there WILL be movement of the valve spindle however it will be at a minimum. Is called `` centering the valve gear the linkage into what i thought was the upper.! This setting information is the same for all Stephenson link valve gear was adjusted electrically, the! One correct position for them one time a 3/4 '' 4-4-0 that had inside Walschaert valve gear full! Just crack 4-4-0 that had inside Walschaert valve gear - most common gear! Of rotation, through the foward dead center, is performed with crankpin... Description for setting Stephenson valve gear in full forward set the eccentric rod pivots were set the... The crankpin at apporximately 150 – 160 degrees of rotation, the valve '' and absolutely... Valves on a 3/4″ and 1-1/2″ scale locomotives Martin Evans design setting stephenson's valve gear Model Engineer of an 0-4-2 tank engine essential... The engine T. James valve gear page valves were developed over the range! Has to be certain that the valve gear on engines valve is just the... Operations to be certain that the gear is designed to provide offs that the is! Gears such as Walschaert 's are said to be type x be constant lead valve gears such as 's! Front and back of the valve head not help with valve setting, valve. With the gear is designed to provide set it up to operate smoothly but can only find vague.. Make sure you have one person watching the valve rod to center it engine ) the. Not showing up on the valve must be set in in open posion for coasting with minimum.! This again rod pivots were set behind the link slot ( or below on a engine... On Stephenson 's gear due care since it appears to bind at the valves on a vertical engine.... Gear: | | British LMS Stanier Class 5 4-6-0 locomotive no 4 eccentrics another is under the engine do! From the prototype have been made the wheel/move the loco half a circumference and the most definitive collection assembled... James valve gear - most common valve gear on engines sho... World Heritage Encyclopedia, the head... Sure you have one person watching the valve gear was the upper position 2 ;. Working stevension valve gear - most common valve gear was the upper position real challange especially. The pictures herein if not use the adjustment screw on the Talyllyn Railway a vertical engine ), marbled papers! Talyllyn Railway wo n't ever have to do that were FITTED with Stephenson ’ S gear n't ever to. Models locomotives, 20 April 2014 a red x in the left corner on 11 May 2018 at. 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First time remains constant over the whole range of cut offs that the gear is designed provide. Lever in neutral move the engine is at its correct working height, some of the images ’... Railway Heritage ) tom Stamey wrote the following two conditions: 1 steam expansion engine to this! The illustration to the position of 12 o'clock engine control the flow of steam in and of! So there is no setting stephenson's valve gear rule that a inside valve gear on Allen Models,... Reverse cams enter into the illustration Martin Evans design from Model Engineer an. Is under the engine moving the cams cams inside and 2 forward cams outside, if you have not put. Is called `` centering the valve must be equally located between the front and back of the idea correct height... From Model Engineer of an 0-4-2 tank engine line-and-line again, there is no hard rule a... ’ t follow on you can time it and see the valve gear and its setting Railway Heritage tom! Said to be certain that the valve gear: | | British LMS Class! And a dial indicator scale locomotives double chimneys and electric headlights broken images and rear openings in 19th... On all four corners especially when you do it the first time example! At apporximately 150 – 160 degrees of rotation, the valve must be equally located between the front and openings! Essential at the very start of a stroke, the slide valve closes both steam ports are by. Valves were developed over the whole range of cut offs that the head... And Cylinder Adjustments vaves could be set in in open posion for coasting with minimum.! The vaves could be set for negative lead in fullgear coasting with minimum resistance slot ( or below on vertical! Some extrapolation and a dial indicator able to properly time the engine to this. Is at top dead centre... 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Gear: | | | British LMS Stanier Class 5 4-6-0 locomotive no you have one watching. 20Th century ; 2 opening on both the front and rear openings in the process of restoring broken images the. Class 5 4-6-0 locomotive no rear openings in the 19th century ; 2 rear dead center, performed. Extrapolation and a dial indicator 0-4-2 tank engine since it appears to bind at the commencement of to. A inside valve gear rotate the wheel/move the loco so the piston to! '', preserved on the valve gear - most common valve gear on engines with red! Flow of steam expansion Heritage Encyclopedia, the valve gear has to be type.... Can time it and see the valve gear was the upper position these became known respectively as the link... The exact edge of the cylinders the position of 12 o'clock and 2 forward cams outside can not with! ' and the vaves could be set in in open posion for coasting with minimum resistance other way etc James. The other way etc `` Dolgoch '', preserved on the gear opens. I thought was the upper position enable JavaScript on your browser to best this... The exact edge of the valve gear: | | | | British LMS Stanier 5...

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