I'm in the process of determining the length of my eccentric rods on my P7, having completed fabrication of the rest of the valve gear. NOTE:- Frames, Coupling rods, connecting rods and outside cranks are not included with this set of parts. (Diagram based on 4-6-2 Pacific, Soo #2714) 1. A site dedicated to enthusiasts of all skill levels and disciplines of the metalworking hobby. I’m back. Too many things going on to bother listing them. If the centre line of valve gear is above the cylinder centre line, as on some of the L.M.S. by Bill Shields » Wed Oct 10, 2012 9:31 pm, Post by DaveD » Sat Oct 27, 2012 2:38 pm, Powered by phpBB® Forum Software © phpBB Limited. Slide valves largely used in the 19th century; 2. 2. Please read the INTRODUCTION first. I always follow the numbers I get from my build and the math in the Greely's Walschaert book. The inventor's name was (Egide) Walschaerts (pronunciation: ay-gee-da val-sherts), but the design was patented under the name Walschaert for political reasons.Ref: Publications Style Manual, Pennsylvania Railroad Technical and … It's that phase of the build again where I need to understand Walscheart's inside admission valve gear. After taking the boiler off and centering the driver bearing boxes in the pedestals with shims, I used the method described at, Favorite Places to Visit In Your Area & Upcoming Events, Site Software Q&A and Maintenance Notices, http://www.jghtech.com/html/ecc-crank-1.html, http://www.jghtech.com/html/dead-center-1.html, http://www.jghtech.com/html/dead-center-1.htmland. The Walschaerts valve gear is a type of valve gear invented by Belgian railway mechanical engineer Egide Walschaerts in 1844 used to regulate the flow of steam to the pistons in steam engines. Piston valves which superseded slide valves in the 20th century; 3. This describes the procedure for adjusting the slide valves on the simplified Walschaerts valve gear as fitted to certain Roundhouse locomotives, so that they open and close at the correct time. [4] Isaacson's patent valve gear - a modified Walschaerts gear, patented in 1907 by Rupert John Isaacson, and others, … The difference between the two positions of the, A given lead determines the lap or a given lap determines the lead, and it must be divided for both ends as desired by lengthening or shortening the, Within certain limits, this adjustment may be made by shortening or lengthening the. 30 (Walschaerts valve gear) The PB15 class were conceived as a passenger version of the earlier B15 class 4-6-0 freight locomotives dating from 1889, hence the ‘P’ prefix. This is where patience is needed, tweak the lever, link & rod until all the pins line up. The combination lever must align the three pins - put the pivot over the union link pin, rotate until the top pin is as close as possible to the radius rod pin. Rules for Timing Locomotives with Walschaert Gear From Friends Steam Models Catalog 5A: 1. by DaveD » Thu Oct 11, 2012 4:57 pm, Post stream Remember that Walschaerts knew nothing about long travels and inside admission valves at the time of invention: some modern designs struggle to emulate the best of those dating from early in the 20th century. Walschaert Valve Gear --. These design requirements are: 1) Cut-off in full gear 2) Maximum port opening in full gear 3) Lead in full gear. by DaveD » Wed Oct 10, 2012 3:33 pm, Post Yet in many presentations they DESIGN AN D INVENTION - 14. The Computer-Aided Design ("CAD") files and all associated content posted to this website are created, uploaded, managed and owned by third party users. 5). The most common design of Walschaert valve gear is that having constant lead. Ron H Member DIGITAL SUBSCRIBER On all my steam locos the radius rod is in a neutral position and does not move the valve stem in … Diagram showing general arrangement of Walschaerts valve gear. Have valve on center of seat. Lifting Arm. Quantities such as steam lap, eccentric throw, angle of advance etc. The primary reason for a more universal adoption of Walschaerts’ gear was its general suitability for mounting outside the frames, convenient for maintenance and permitting more strongly braced frames. It was extensively used in steam locomotives from the late 19th century until the end of the steam era. The pressure of this steam provides the driving fo… There are very few engineers, model or full size, who FULLY understand the workings of these valve gears, resulting in many of the published designs exhibiting minor and even major design … Adjust the valve so that its line to line at the exhaust. The valves on a steam engine control the flow of steam in and out of the cylinders. Place the radius rod centered in the link. 2 years ago. by LSGOD » Thu Oct 11, 2012 11:02 am, Post from Kieran Jones. Assuming the valves are line to line (exhaust) disconnect the lap and lead lever and set it vertical. Instead of a sliding die piece, Baker used a series of pin joints to achieve the same result. At any setting, the valve gear satisfies the following two conditions: 1. USING VALVE GEAR SIMULATORS by Don Ashton ... of this is that simulators can be used as a useful tool in designing valve gears but are not in themselves design programs: since they may have the ability to ignore first ... Walschaerts’ gear. The Walschaerts valve gear is a type of valve gear invented by Belgian railway mechanical engineer Egide Walschaerts in 1844 used to regulate the flow of steam to the pistons in steam engines. 2). A CLOSE-UP of the Baker valve gear applied to a New York Central fast freight locomotive.This gear was invented in 1903 and first used on a traction engine. Use inside calipers. Even used Google to search chaski without success. THE ORIGINAL VALVE GEAR designed by the Belgian engineer, Egide Walschaerts, in 1844, employed an eccentric in conjunction with the crosshead to operate the valve. This also works for Baker. Service Sheet 02 Walschaerts Valve Gear Valve timing adjustment on Roundhouse locomotives. by DaveD » Fri Oct 12, 2012 8:01 am, Post by Bill Shields » Thu Oct 11, 2012 4:33 pm, Post by Fred_V » Thu Oct 11, 2012 5:37 pm, Post References. Don Ashton's final edition of his well known book on designing Walschaerts and Stephenson's valve gear is available again, reprinted by agreement with him. M… Block up wheels in running position. … I should remember having had the need in the past to do the same thing that I am currently 3. Lifting Link. The eccentric rods length determines if the link swings equally front to back. Measure from dummy pin in link to eccentric crank pin and repeat for back dead-center. Online Program for Valve Gear Design (Walschaerts, further valve gears coming later): ValveGear Constructor To get a translation function for the main site and (some) subsites, click on the flag right on top of the main site and follow the instructions. Invented in 1844 by Egide Walschaerts, foreman of the Belgian State Railway. The gear is sometimes named without the final "s", since it was incorrectly patented under that name. Animation of the Walschaerts valve gear mechanism used in steam locomotives to control the motion of the drive wheels. 4. In 1844 Egide Walschaerts invented a valve gear that by 1848 appeared very much as it does today. by hudson » Thu Oct 11, 2012 3:42 pm, Post Don Ashton’s site devoted to steam locomotive valve gears and their design, kinematics and distribution problems, particularly for Walschaerts’ and Stephenson’s gears. and Southern engines, it makes no difference to the procedure; all you do is to keep the link square with the centre-line of valve gear when in mid-position. Then set the expansion link in mid position so that the radius rod (8) passes up and down without moving the link. The T end of the eccentric rod carries two pins; the lower pin is shown engaged with its slot in the reversing link. Revised, enlarged printing of Don Ashton's book Walschaerts Valve Gear for Model Engineers & Stephenson's Valve Gear for Model Engineers. Specifically, I'm at the point where I have scaled the valve gear from the prototype, tweaked it with Docstader's program and with a lot of help from the good people on this forum, built the gear, and as a final step built a template to precisely size the center distance of the eccentric rods. Poppet valves similar in principle to those used in internal combustion engines. Do not use it for any valve adjustments. By the way, Walschaert gear is correct; Walschaerts gear is not (unless it is used in the possessive case, with an apostrophe, eg: "Walschaerts' design"). Further Methods of Distributing Steam to the Cylinders. Increasing the lap introduces the opposite effect on the cutoff. Each CAD and any associated text, image or data is in no way sponsored by or affiliated with any company, organization or real-world item, product, or good it may purport to portray. The program itself can be switched to English or German language within the headline. Done. 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. 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. by JJG Koopmans » Thu Oct 11, 2012 3:00 pm, Post important design requirements are obscured. Would someone point me to a thread on chaski that describes how to go about timing the valve gear on a Walschaerts locomotive? With good judgment, these qualities may be varied to offset other irregularities inherent in transforming rotary into lineal motion. 3). are important only insofar as they allow the above design requirements to be achieved. Don Ashton is a recognized expert in the design of valve gears for the model steam locomotive. by DaveD » Thu Oct 11, 2012 11:31 am, Post The gear is sometimes named without the final "s", since it was incorrectly patented under that name. History and help for the smaller gauges. 5. Since the inventor was unable to modify the design, the valve gear was replaced by standard Walschaerts gear between 24 March and 11 April 1934. Walschaerts Valve-Gear Part Number WVG Assembly of Walschaerts type valve-gear 1). A key difference was the larger diameter driving wheels, being 4’ for the PB15 class as opposed to the … Radius Rod. STEAM ENGINE VALVE GEAR ON THE COMPUTER Windows Version by Charles Dockstader HCR 69 Box 3111 California Valley CA 93453 805 475 2519. Late 19th century until the end of the Belgian State Railway series of pin joints to achieve the same.. Of Walschaert valve gear that by designing walschaerts valve gear appeared very much as it does today types of valves developed! 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