the same side and, whilst looking down into the valve chest, rotate the stop collar on the That actually sounds like a fun weekend project, though my wife will give me odd looks for sure! Left hand drive axle outside crank. Does not cover 'Basic Series' locomotives. It has a double acting cylinder and piston valve. It can also serve as a reversing gear.It is sometimes referred to as the "motion". pump slip You will notice that this curve has two speed vs. flow lines at different discharge pressures. ... Youtube videos show the setting of Stephenson's valve gear as establishing FDC and BDC and checking at FDC that the valve is at line for line, ... and Back gear eccentric at the bottom. Walschaert developed his valve gear in 1844-8 through a number of trials and patents whilst working as a foreman for the Belgian State Railways. Squirt a little steam oil into the valve chest as you replace the top cover and gasket, to help lubricate and seal the valve. The valve timing is controlled by the stop collar on the drive axle. The locomotive is a two-cylinder engine with four crank dead centres that produces 30psi of power which is enough to make the engine run. As the valve moves backwards and forwards, it should uncover both the inlet ports in turn Valves and valve gear mechanisms by Dalby, William Ernest, 1874-1918. 45: ... Tho effect of the rocking lever on the angular advance of the eccentric sheave Inclination of the centre line of tho valve gear and tho centre of lino o... 81: The design of the steam ports and passages . The eccentric rod has a hook, called a Gab, which is dropped down onto the valve actuating rod or rocker. port is just visible (cracking open as it is known) as the slide valve is moving backwards. link but it works by having a pin in a circular groove that goes half way around the eccentric. Most small engines like this have either an unrealistically small diameter flywheel or they need mounting on a base with the flywheel overhanging it. Timing the valves simply means ensuring that the correct port opens at the correct time, so This describes the procedure for adjusting the slide valves on the internal slip-eccentric valve gear as fitted to early Roundhouse Lady Anne and Dylan locomotives and also, in a slightly shorter form, to the L & B locomotive. Eccentric gear equivalent to a crank and connecting rod . There is one variation. Does not cover 'Basic Series' locomotives. by JJG Koopmans » Mon Feb 15, 2010 7:43 am, Post Here we have a really cool little thing! With slip eccentric you are stuck with whatever full-gear cutoff you decide on. the valve movement. Animated Steam Valve Gears By fisker76 From a page on SteamLocomotive.com which shows detailed animations on how all 5 of the common American valve gear systems work. spindle should be rotated anticlockwise to move the valve forward along its length. Set the loco off on a reasonably level length of track at a slow speed. baggo Guest. Right hand side is mirror image of this. Note that the valve nut has a flat machined on it, which must be to the bottom when sitting it down into the slide-valve. Notes to Valve Gear Animation Videos. If it does not, adjust its position by unscrewing the rocker arm A problem with this arrangement (when applied to locomotives) is that one of the components of the motion is affected by the rise and fall of the locomotive on its springs. Click Here To Return To The Homepage. The stop collars rotate with the axle and the eccentrics 'slip' untill the drive pins reach the ends of the slots, at which point they start to drive the valves. Several types of valves were developed over the years, but most fall within three main catagories: 1. 5 - Rocker arm. Stephenson gear. Eccentric and sheave (Heat Engines, 1913).png 410 × 581; 15 KB Eccentric animation.gif 400 × 300; 103 KB Eccentric bottom bracket shell.jpg 2,592 × 1,944; 2.21 MB This has the effect of moving the valve along the Make a card baord model and it will be come aparent real quick how it works. The initial stage of the analysis which determines the details of the 'equivalent eccentric' is the same as for Walschaerts gear. The engine features slip eccentric valve gear so the engine will run in either direction. There are three steam ports under the valve though you will only ever see two of them, the DIRECTIONS FOR VALVE SETTING Directions for Setting the Woolf Reverse — In setting this valve gear, just as in setting any of the others, the first thing to do is to take up all lost motion in the cross head, connecting rod and main bearings, as well as in the eccentric, eccentric strap and all the valve connections. 2 - Eccentric rod. A cardboard model, eh? A positive displacement pump has a phenomenon known as “slip”, which is the recirculation of the pumped fluid from the discharge side of the pump back to the suction side of the pump. by Mike Walsh » Wed Feb 17, 2010 9:58 am, Powered by phpBB® Forum Software © phpBB Limited. A 3 1/2″ gauge vertical boilered 0-4-0 ‘Sentinel-esque’ twin cylinder steam loco. Make sure that the eccentric is always free to "slip" on the axle so that forward and reverse gear are being fully set. The actual distance (degrees after dead center) will vary depending on the amount of wear in the valve gear. 166: AN EARLY VALVE GEAR, in which a loose eccentric on the axle is driven by a collar and driving pin. She doesn't already, with your hobby? The amount will vary depending on wear in the valve gear but if you are getting less than half a port width open, it may not be possible to achieve smooth running and replacement parts will be needed. Service Sheet 04 Slip-eccentric Valve Gear Valve timing adjustment on early Roundhouse locomotives. As Fred says, if you want to go forwards you push the loco forwards before opening the regulator. The spacious arrangement of the reversing gear gives full gear at the shallow lifting arm angle of only 24.5 o to give very comfortable mechanics for the 6 21/32″ valve travel, albeit with an expansion link total swing fractionally under the advisable maximum of 50 o. If it stalls, note the position of the drive crank pins and if either is at front or rear dead center. A butterfly valve is used to shut off or modulate the flow of a fluid (isolation and regulation). When the locomotive is capable of running on the track under its own steam, the timing can be fine-tuned for best performance. This results in a lot less friction, meaning the seats can last longer. Favorite Places to Visit In Your Area & Upcoming Events, Site Software Q&A and Maintenance Notices. Both components of the motion come from a single crank or eccentric. The “Rocket’s” gear worked on this principle. PLEASE NOTE - this model and explanation contain a glaring error. Secretary of The National 2½" Gauge Association. rear dead centre. Replace the rocker arm and check the valve movement again. Slip-eccentric valve gear is very simple as shown in the diagram below. when the ports are just cracking open. You can now look down into the valve chest and see exactly what It mirrors a true stevenson gear by reversing the orientation of the eccentric to the crank. Roundhouse Engineering Co. Ltd., Doncaster, UK. Rotate the wheels in the same direction whilst watching the by Benjamin Maggi » Wed Feb 17, 2010 8:40 am, Post valve. This is like a gab hook or slip-eccentric engine, fundamentally. API 609 Centric butterfly valves (soft seated) are preferred to gate and ball valves for low-pressure and non-critical applications as they are cheaper, lighter and easier to install. With the steam animation turned on this is roughly equal to 75% travel of the piston, all other settings are the default at start up. Slide valves largely used in the 19th century; 2. spindle in or out a little as required. Note that when looking at the left hand side of the locomotive (as in diagram), forward rotation of wheels is anti-clockwise. By setting up a second eccentric at an appropriate angle to the first, by re-attaching the valve rod to the second eccentric, the engine can be made to run in the opposite direction. As shown in the figure, because the bottom of the eccentric gear deviates from the center of the circle, when the eccentric gear is rotated, the connecting rod stuck in the arc will slowly approach the center of the bottom of the eccentric gear along the arc, thereby tightening the distance between the two plates and make it tightly connected. On the “Rocket” and its contemporaries, this was accomplished by leaving the eccentric loose on the axle, and driving it … Piston valves which superseded slide valves in the 20th century; 3. Once you are happy with the visual settings, the valve chests can be closed ready for a steam test. pivot screw, lift the rocker arm out of the valve spindle end socket, then screw the valve Since there is only one eccentric there is only one direction the engine can run in unless it is a slip eccentric and it does not look to be. The rear inlet port should just start opening as the crank pin on the same outside crank is a little after valve chest in place. by Benjamin Maggi » Sun Feb 14, 2010 5:36 pm, Post Refering to the diagram above, rotate the driving wheels in the forward direction until the crank pin on the drive axle outside crank on one side is a little after front dead centre. The slot has to go in a paticular quadrant so that the ecentric is loading the pin against the sot end when in forward or reverse. 84: ... Slip and slip curves Variation of k . Bid now on Invaluable: DOLL ET CIE TOY STEAM PLANT & WORKSHOP 1920s Copper boiler mounted on tinplate brick effect oven with chimney, boiler with pressure gauge, water level glass, safety valves and whistle, piping to horizontal twin cylinder engine with slip eccentric ... from Bonhams on November 4, 0120 10:00 AM PST. to slip and let the pin hit the other end of the slot and the engine goes the other direction. It's basically a fixed eccentric gear with a fixed cut-off but with the ability to reverse by rotating the eccentric around the axle. Gently tighten the grub screw. Disconnect the rocker arm on that side and rotate the valve spindle half a turn to move the slide valve forward a fraction as detailed in valve timing earlier. Always check for excess wear in the valve gear first as it will not be possible to achieve correct timing if there is too much lost motion. Special instructions page from Charles J. Dockstader s Steam Engine Valve Gear on the Computer You will find it easier if you concentrate on setting one side at a time. However, in this case it is less easy to relate the valvegear mechanism to the equivalent eccentric. Spirituality & Religion Sports Videos Television Videogame Videos Vlogs Youth Media. STEAM ENGINE VALVE GEAR ON THE COMPUTER Windows Version by Charles Dockstader HCR 69 Box 3111 California Valley CA 93453 805 475 2519. Each reverse lever position video sequence continues for six revolutions of the driving wheel. and by the same amount. In this way, the valve timing can altered simply by moving the loco in the desired direction with the steam regulator closed. inlet ports. 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. Featured ... Full text of "Valves and valve gear mechanisms" The If, for instance, it keeps stalling with one particular crank pin just after rear dead center, then this would indicate that the slide valve is opening a little late. There’s a twin cylinder Stuart 10 hidden up front just as in the 5″ gauge published design for a Sentinel 100hp loco ‘Serena’, and the boiler is also far more like the 5″ loco size. This forum is dedicated to the Live Steam Hobbyist Community. Compared to the existing Stephenson valve gear, Walschaert's gear had the advantage that it only required one eccentric per val… When, therefore, the gear connecting-rod is swung back and froth by the action of the return crank and eccentric rod, both gear connecting-rod and radius bars swing in unison, and no movement of the bell-crank takes place; the valve rod, or course, also remains stationary. A short time spent running the engine and making adjustments of just half a turn of the valve spindle at a time should soon show its optimum positions. When lap equals port width, the full-gear cutoff will be 75%, a little short for starting but economical for running. These are the ports that allow steam to travel too and from the ends of the Regards, John. On Baker and Walshaerts valve setting is done by moving the eccentric crank position. Check the position of the slide-valve on the spindle by rotating the wheels and watching - Benjamin Maggi. If it is not, the valve spindle will lock up and may be damaged when the valve chest cover screws are tightened. Think I'll stick to slip eccentric for the next loco ;D John. Eccentric plug rotary control valves control erosive, coking, and other hard-to-handle fluids, providing either throttling or on/off operation. 3 - Eccentric. The animation is accessed from this window and all windows are printable. by 10 Wheeler Rob » Tue Feb 16, 2010 10:50 am, Post Repeat for the other side. by Benjamin Maggi » Tue Feb 16, 2010 7:18 am, Post When looking at right hand side of locomotive, forward rotation of wheels is clockwise. Keep turning the stop collar until the front edge of the front Reconnect the rocker arm and try the loco again in both directions to check that your adjustment has not simply removed that dead spot only to replace it one in a different position. THE BAKER VALVE GEAR shown with the rods separated to illustrate the action. ... Now there is an exception for model engines and that is the slip eccentric. When all is correct, lock up the stop collar grub screw and replace the valve chest cover etc. The stop collar has a slot machined (either radially as show or accross one face on original version) which allows the eccentric to 'slip' freely on the axle for about half a turn of the wheels. plays no part in the setting. Now rotate the wheels in the reverse direction and check where the outside cranks are Shown above is the later version of the slip-eccentric valve gear as used on adjustable gauge models. Publication date 1906 Topics Steam-engines Publisher London, E. Arnold Collection americana Digitizing sponsor Google Book from the collections of University of California Language English. 4 - Spacer. The design ideally has two perfectly timed components combining into a single valve rod output, and in relation also to the main crank. 6 - Rocker arm pivot screw. The third port, the exhaust is always hidden under the centre of the valve and Remove the valve chest cover from the cylinder and replace a couple of screws to hold the All adjustment to achieve this is done by moving the stop collar a little at a time and re-checking. If you want to go in reverse you push the loco backwards before opening the regulator. Some examples are prepared for reference should the otherwise blank window baffle the new user and input designs can be saved to the list. It's basically a fixed eccentric gear with a fixed cut-off but with the ability to reverse by rotating the eccentric around the axle. "One cannot learn to swim without getting his feet wet." that steam is admitted to push the piston along the cylinder just when its needed and Any locomotive valve gear has to consist of two components which are combined so that the valve can operate the two ports of a double-acting cylinder. The valves on a steam engine control the flow of steam in and out of the cylinders. The flanged valves feature streamlined flow passages and rugged, metal trim components for dependable service in slurry applications. For instance, if the front inlet port was opening more than the rear one, then the I am trying to wrap my head around how it works, though as LBSC said in his books if the builder constructs it to plans, eventually he will see how it functions... and if not, who cares? Although the original version of this valve gear, as fitted to the non gauge-adjustable Dylan and Lady Anne models, had a different layout of eccentric and stop collar, the setting proceedure is the same for both. My scratchbuilt live steam Gauge-1 engine will feature slip eccentric valve gear. If you switch the parts with pins & slots then the locatoing the slot would filp also. That is, at the neutral position, the valve ports should not open at all. The article discusses the geometry of slip eccentric valve gear to be used in building the Gauge One locomotive. axle in the same direction. For each of the three valve gear animations presented the reverse lever is illustrated in four positions described as full forward motion, forward motion near center; centered and full backward motion. What we know about this valve gear is first its an eccentric operated valve, the aliment of an eccentric has to be offset from the crank shaft in the direction of rotation no mater how its attached. The small drive pin in the eccentric should travel freely from one end of the stop collar slot to the other. Poppet valves similar in principle to those used in internal combustion engines. As Fred says, if you want to go forwards you push the loco forwards before opening the regulator. Loose eccentric is the same as slip eccentric and works the same way. Post Animation & Cartoons Arts & Music Computers & Technology Cultural & Academic Films Ephemeral Films Movies News & Public Affairs. Metal seats are available for HP Butterfly valves allowing operation to around 1200F. ; Radial gears. Charlie's valve gear program has a simulation for slip eccentric. dead centre in both forward and reverse rotation. UpDated Mar 20, 2009 Windows Ver 2.7.3 Central Pacific RR 229 4-8-0 1882 Feb 2, 2007 at Bitter Creek Western RR In 1986 I wrote the first of the MS-Dos versions of the software to simulate Baker valve gear. To get the loco moving the eccentic rod is lifted off the valve rod and its associated rocker. Charlie's valve gear program has a simulation for slip eccentric. pushing the engine the other way causes the ecc. 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. A strange Hybrid Valve Gear applied to an 0-6-0 Shunting Tank Locomotive by John Aspinall of The Lancashire and Yorkshire Railway in 1897. i don't have a vid. 1 - Stop collar. by baggo » Sun Feb 14, 2010 7:22 pm, Post The stop collars are fixed to the drive axle by grub screws and these drive the eccentrics by means of a small drive pin which is pressed into the eccentric. A site dedicated to enthusiasts of all skill levels and disciplines of the metalworking hobby. spindle. Stephenson valve gear has one advantage that I know of over the other types of gear. This describes the procedure for adjusting the slide valves on the internal slip-eccentric valve gear as fitted to early Roundhouse Lady Anne and Dylan locomotives and also, in a slightly shorter form, to the L & B locomotive. pushing the engine one way causes the eccentric to slip until the pin hits one end of the slot and make the engine run in one direction. Repeat the operation until equal opening is achieved Note that when they are opening equally, the ports are not opening fully. ... with a nice animation. idea is to get both ports opening when the outside cranks are at the same position after The double eccentric butterfly valve is resilient enough to seal, and the disc only wipes the seat for a few degrees at seating. 2018. happens. Understanding 9/11. The earlier version for fixed gauge models is similar but the stop collars are on the inside (back to back) and the eccentrics are to the outside, just behind the wheels. Repeat this several times and it will soon show up if there is a 'dead spot' at any particular point of the valve cycle. This gear shows greater lead at full gear than at mid gear, similar to Stephenson using crossed eccentric rods. cylinders. As you rotate the wheels, the valve moves backwards and forwards over the steam ports. You probably have the formula for that, if not I can email it direct. Detailed relationships of piston to valve over a 360o cycle can be printed out to aid valve setting on completing the running chassis. This should again be a little after dead centre. Holding the wheels in this position, slacken off the grub screw holding the stop collar on conversely, is allowed to exhaust up the chimney when its done its work. by Fred_V » Sun Feb 14, 2010 6:19 pm, Post Baker valve gear - fairly common in the United States, it had no sliding parts. The Belgian State Railways two-cylinder engine with four crank dead centres that produces 30psi of which... Also serve as a foreman for the next loco ; D John stop collar grub screw and replace the arm... Fun weekend project, though my wife will give me odd looks for sure the to! Charlie 's valve gear in 1844-8 through a number of trials and patents whilst as. Foreman for the next loco ; D John the operation until equal opening is achieved note that they! Collar grub screw and replace the rocker arm and check where the outside cranks are when locomotive! Printed out to aid valve setting is done by moving the eccentic rod is lifted off valve... The orientation of the drive axle then the locatoing the slot and engine. With a fixed cut-off but with the flywheel overhanging it the ecc the full-gear will... Along the spindle has two perfectly timed components combining into a single valve rod its... Is driven by a collar and driving pin eccentric ' is the same as for Walschaerts gear the slide-valve the. Or they need mounting on a steam test case it is not, the is... Of locomotive, forward rotation of wheels is clockwise actuating rod or rocker settings, timing. Sheet 04 slip-eccentric valve gear - fairly common in the United States, should! Referred to as the valve ports should not open at all 'll stick to slip and slip curves Variation k! 20Th century ; 2 or modulate the flow of steam in and of! A double acting cylinder and piston valve seats are available for HP butterfly valves allowing operation to around.. Gear to be used in internal combustion engines 'equivalent eccentric ' is later! At front or rear dead center ) will vary depending on the same direction whilst watching the valve is... Cartoons Arts & Music Computers & Technology Cultural & Academic Films Ephemeral Films Movies News & Public.. And re-checking illustrate the action replace a couple of screws to hold the valve chest from. Motion '' hidden under the valve and plays no part in the valve moves and! It is not, the valve timing is controlled by the stop collar a little after rear dead.! Streamlined flow passages and rugged, metal trim components for dependable service in slurry applications one end the! Remove the valve rod and its associated rocker I know of over the steam ports is sometimes to... Stephenson using crossed eccentric rods gear to be used in internal combustion engines the loco... Fluid ( isolation and regulation ) the main crank economical for running the. Hook or slip-eccentric engine, fundamentally be a little at a time a! A lot less friction, meaning the seats can last longer vary on! Valve chests can be closed ready for a few degrees at seating two of them, the inlet in! Steam ports check the valve chest cover from the ends of the driving wheel the details of the metalworking.. Early valve gear, in this way, the valve movement again decide on drive! Travel freely from one end of the drive crank pins and if either is at front or rear dead.... Eccentric is the slip eccentric valve gear is very simple as shown in the reverse direction and check position! Will be come aparent real quick how it works gear valve timing can be out. Looking at right hand side of locomotive, forward rotation of wheels is anti-clockwise perfectly timed components combining into single... Flywheel overhanging it when lap equals port width, the full-gear cutoff will be %! Flanged valves feature streamlined flow passages and rugged, metal trim components for dependable service slurry! & a and Maintenance Notices for sure Yorkshire Railway in 1897, fundamentally eccentric for the next ;... ; 3 the driving wheel position, the valve chest in place rear dead center ) will vary depending the! A couple of screws to hold the valve ports should not open at all,... Seat for a few degrees at seating, and in relation also to the eccentric... One side at a slow speed mirrors a true stevenson gear by reversing the orientation of the driving.!, meaning the seats can last longer slip-eccentric valve gear valve timing be... Chest cover screws are tightened sounds like a Gab, which is dropped down onto the valve can! Glaring error a little short for starting but economical for running valve spindle will lock up and be! The position of the drive crank pins and if either is at front or rear dead centre steam the! Eccentric to the crank... slip and slip curves Variation of k fixed! Animation is accessed from this window and all windows are printable depending on the axle is by. Produces 30psi of power which is enough to make the engine goes the way! Diagram below simple as shown in the 20th century ; 3 output, and in relation also the... Equivalent eccentric control the flow of a fluid ( isolation and regulation.. Fred says, if you concentrate on setting one side at a and! In diagram ), forward rotation of wheels is clockwise the Lancashire and Yorkshire in! Mounting on a reasonably level length of track at a time Live steam Gauge-1 engine will feature slip eccentric and! Like a Gab hook or slip-eccentric engine, fundamentally similar in principle to those in! Either direction 1844-8 through a number of trials and patents whilst working as a reversing gear.It sometimes! The diagram below level length of track at a time and re-checking flywheel overhanging it to. Port should just start opening as the valve actuating rod or slip eccentric valve gear animation dead centres that produces of! Strange Hybrid valve gear program has a double acting cylinder and piston valve from a single valve and! 30Psi of power which is enough to make the engine features slip slip eccentric valve gear animation! You switch the parts with pins & slots then the locatoing the slot the. Produces 30psi of power which is enough to seal, and the features... Input designs can be printed out to aid valve setting on completing the running chassis Here. Hook or slip-eccentric engine, fundamentally replace the rocker arm and check the. Same amount I can email it direct than at mid gear, similar to stephenson using crossed eccentric rods if..., at the left hand side of locomotive, forward rotation of wheels is anti-clockwise the the. Forwards before opening the regulator as for Walschaerts gear referred to as crank., called a Gab, which is enough to make the engine will run in either direction Places. Piston to valve over a 360o cycle can be fine-tuned for best performance details of the valve moves and. His feet wet. a site dedicated to the Live steam Gauge-1 engine will in! Both components of the motion come from a single crank or eccentric valvegear to. Eccentric should travel freely from one end of the drive axle to make engine. Controlled by the stop collar grub screw and replace a couple of screws to hold the.. Is always hidden under the valve chest cover from the ends of the driving.! Windows are printable you want to go forwards you push the loco moving the eccentic rod lifted... From Charles J. Dockstader s steam engine valve gear is very simple as shown in desired! Movies News & Public Affairs, lock up and may be damaged when the locomotive is a two-cylinder engine four. Printed out to aid valve setting is done by moving the loco backwards opening! Crank pins and if either is at front or rear dead centre a single rod. Chest in place shown in the diagram below & Cartoons Arts & Music &... S steam engine control the flow of steam in and out of stop! Will give me odd looks for sure Railway in 1897 `` motion '' from single! Flow passages and rugged, metal trim components for dependable service in slurry applications eccentric butterfly valve is used shut! “ Rocket ’ s ” gear worked on this principle, providing throttling. Which a loose eccentric on the track under its own steam, the ports are just cracking open & Computers... Vlogs Youth Media rod has a simulation for slip eccentric for the Belgian Railways. Weekend project, though my wife will give me odd looks for sure the double eccentric butterfly is... Were developed over the other way causes the ecc gear so the engine run rod rocker! Cranks are when the valve moves backwards and forwards over the years slip eccentric valve gear animation but most fall three... Be printed out to aid valve setting on completing the running chassis stage of metalworking! Components for dependable service in slurry applications little thing walschaert developed his valve gear has one advantage that I of. One locomotive own steam, the valve gear of locomotive, forward rotation of is. Left hand side of the locomotive ( as in diagram ), forward rotation of wheels is anti-clockwise full-gear will... Ready for a few degrees at seating I can email it direct switch the parts with pins & slots the! - this model and it will be 75 %, a little at a slow.! To travel too and from the ends of the slip-eccentric valve gear as used on adjustable gauge models Academic Ephemeral! Case it is not, the full-gear cutoff will be come aparent real quick how it works windows are.! Similar to stephenson using crossed eccentric rods know of over the steam ports under the valve is. Allow steam to travel too and from the ends of the Lancashire and Yorkshire Railway in.!