96RAF Posted September 14, 2019 Share Posted September 14, 2019 Inward relief valve Ken, same as they have in aircraft rubber bag fuel tanks to allow them to equalise internsl pressure after descent, so they don’t collapse... Link to comment Share on other sites More sharing options...
gowest Posted September 14, 2019 Author Share Posted September 14, 2019 /media/tinymce_upload/11297b0383c375736e113687b97db3b8.jpgThis idea came about because I took a supper heater apart to remake it into a slightly smaller unit to fit a GWR tank engine.Once apart a close look at the inner section of the supper heater showed an oil like residue as in the picture and this oil appears to be thicker on the right hand end than on the left hand end which leads me to believe that when the engine is cooling down a vacuum builds up in the tender boiler and the only way the air can get to the tender boiler is via the engine and it may be that this black gunk is old oil burnt onto the supper heater. This in time will damage the supper heater and even block the small passageways of slow the steam down to a point that the engine appears to be a poor steamer. Also it quite possible that bits of this black gunk can block other small passageways to the cylinders also giving poor steaming./media/tinymce_upload/ab41984db1c7a30a92d3e5c088cbc8a5.jpgTo over come this problem my idea is to change the filler screw in the tender to a vent valve this valve will stay in the closed position by a spring and rubber O ring as boiler pressure builds up all that will happen is that the O ring will be pressed harder into it seat and keep the valve shut.When the engine has been put away and a vacuum builds up the valve will come away from its seat and air allowed into the tender tank.You can just undo the filler screw for the same effect but this way it would be fully automatic. /media/tinymce_upload/fe62fc62a98d78b311f8470701052e6a.jpgHere is the test model it is slightly longer than the Hornby one it can be made the same size if the idea works./media/tinymce_upload/1ac3271a76369de2cc3bdc9de6f269c1.jpgThe next picture is of the main parts to the new valve the body end the spring the shaft the O ring and the body top./media/tinymce_upload/9e6947f32e5699aa8fea393bd6ed3541.jpgHere you can see the small hole in the bottom end./media/tinymce_upload/0568190d2ff102ac451b77ab169a4318.jpgAnd in this picture is the top end showing the small hole in the screw driver top part.I will carry out some test to see what happens and let you know. Link to comment Share on other sites More sharing options...
96RAF Posted September 14, 2019 Share Posted September 14, 2019 Can you rig a locking pin to secure the two body halves Ken, as I can see the lower part staying in the housing whilst the top end unscrews and the valve innards fly out. Link to comment Share on other sites More sharing options...
gowest Posted September 14, 2019 Author Share Posted September 14, 2019 Hi Robgood point a locking device I think I will go in the work shop tomorrow and see if I can make the new filler screw the same length and as the Hornby one and as you say add a locking device like maybe a screw unless you have any ideas? If we make a thousand at a £1 each this time next year will be millionaires Rodney! Link to comment Share on other sites More sharing options...
96RAF Posted September 14, 2019 Share Posted September 14, 2019 Ken I’m not sure what dimensions you have to play with but I thought assemble the valve then drill from the top end into both parts for a simple press in wire pin, but likely it would be less than 1mm and would need to be piano wire to resist the shear loads when undoing the whole vallve for filling purposes. Thought has to be given to dismantling the valve for maintenance, so the pin hole would have to be right down the length rather than a stopped hole, so you could drive it out when required. Link to comment Share on other sites More sharing options...
gowest Posted September 15, 2019 Author Share Posted September 15, 2019 Good point Rob will look into a locking device but I have had an idea to stop oil back feeding into the supper heater on these engines as others might have but not posted here.ENGINE SHUT DOWNWhen you are thinking of stopping your engine and not using it for a while then run the engine with the power from the controller OFFso the engine is running but just using up the steam stored in the tender once the engine has come to a halt switch ON the controller and move the regulator till the whistle sounds and then power OFF again and leave to cool down this way air can enter via the whistle and not the oil tank. Link to comment Share on other sites More sharing options...
gowest Posted September 16, 2019 Author Share Posted September 16, 2019 /media/tinymce_upload/b7cfe9ddd3540f5d3a7f5855c371825c.jpgI hope you can see in this picture I have incorporated Robs idea for a locking device this is by way of a screw1.2 x 8 mm and links the bottom of the filler screw to the top and stops the 2 half's from unscrewing I have also shortened the filler screw to be the same size as the Hornby filler screw so that the coal cover fits nicely.Tests to follow but do not want to spend too much time on this if it does not work properly as I think I’m getting diverted from the building of the engine. Link to comment Share on other sites More sharing options...
gowest Posted September 24, 2019 Author Share Posted September 24, 2019 Breather TestsThe new breather screw was fitted to the tender of Silver Fox an A4 engine for the first part of testing which was to see if the small valve with its rubber O ring would leak steam or be a good gas type fit./media/tinymce_upload/db459c0789c673324e3f65506a9cebc7.jpgThe tender was filled with water and the engine left to steam up and very soon water was visible around the edge of the new filler screw but not from the valve centre. The question was why was water appearing here and what might be the cause ?/media/tinymce_upload/9418cc647cbf5840cf0df504d5c5960b.jpgThe engine soon obtained full pressure and the safety valves lifted so a steam run was undertaken and the regulator opened off the engine went and ran for a few laps of my small layout after a time the engine was stopped and no sign of water could be observed but it was because any leaking now would be steam so less detectable more steaming produced the same results leaks from the new filler screw to start with then clear. The problem was not the bottom rubber seal fitted to the new screw but the way the 2 halves of the new screw were fitted together as follows./media/tinymce_upload/fd5dc1eaa99fdce2b0652a9d08d44e5c.jpgif you look at the drawing once again the 2 parts circled in red do not have any sealing they arte just screwed together and looking at the construction steam will pass through the small bottom hole indicated by the blue arrow into the chamber and leak out pass the outside screw threads which is where the water could be seen emerging.To over come this problem the threads in this area were coated in gasket cement then screwed together. The tests were rerun and no sign of leaks could now be seen so the fault was corrected.Vacuum test follows Link to comment Share on other sites More sharing options...
96RAF Posted September 24, 2019 Share Posted September 24, 2019 So far so good Ken.Just don’t use the grade that seals forever just in case you need to service the vacuum valve. Link to comment Share on other sites More sharing options...
gowest Posted September 24, 2019 Author Share Posted September 24, 2019 Vacuum testTesting the new filler valve started by connecting a Pressure/Vacuum gauge to the tender boiler output pipe connection. The gauge will record both the steam pressure and vacuum which will be generated by the tender boiler./media/tinymce_upload/9ec63619dbf7c88e2059b5b9f90f5d3b.jpgTo start with the standard Hornby filler screw was used to see what happens and the tender boiler was allowed to steam up and then cool down and at this point the gauge showed that a vacuum figure of 17 had been reached and if connected to an engine might well have let oil into the supper heater and on the next run will burn and produce carbon and a blockage at a later time and hard to remove.Once again the tender boiler was filled with water and the boiler left to steam up but this time the new filler screw was to be fitted and the Hornby one removed./media/tinymce_upload/f1d029139c8d4626a259176fd994ae85.jpgIn the picture here you can see the filler screw has been removed so allowing the steam to escape and replace any air that might be inside the boiler. When sufficient steam has escaped the screw was replaced and the boiler continue to build up pressure./media/tinymce_upload/58ebef9adbd6791921ecdaf4ef8cc8ba.jpgIn this picture the steam pressure is coming up to 6 psi which is enough for the vacuum test.The idea is to turn off the power to the tender and let the tender boiler cool down and see how much vacuum builds up before the valve opens to let air into the boiler./media/tinymce_upload/3d41f0b4734b46b589f7b911717732ac.JPGIn this picture the gauge is showing a very small vacuum of less than 5 and never gets any greater which means air is entering the tender tank via the valve as a much higher value was reach with the Hornby filler screw.This vacuum did not increasing at any time but stayed the same all the time so was the filler valve off its seat and letting air into the boiler?/media/tinymce_upload/92215c73e2ce40db1a3546336e02ac06.jpgOne way to check this was to drop water onto the valve as here in the picture and see what happens to the water and sure enough the water was sucked passed the valve stem into the screw and so must be going into the boiler itself.This action meant that the vacuum was not building inside the tender tank and so protecting the supper heater from ingesting oil from the oil tank. Carrying out further testing showed that the pressured of the valve spring would affect at which point the valve would open letting air into the tender tank but this might be a balancing act as good contact will be needed to keep a good steam seal when running but I think I have proved a point in the design and a change is needed should any one wish to follow my findings here.I hope to draw a line under this part of engine building as I think its time I returned to the engine in question Link to comment Share on other sites More sharing options...
96RAF Posted September 24, 2019 Share Posted September 24, 2019 Job well done Ken. Link to comment Share on other sites More sharing options...
gowest Posted September 29, 2019 Author Share Posted September 29, 2019 /media/tinymce_upload/c683c00ec5677a2d550b07c78431adfe.JPGAn update and what’s been happening this valve idea has had a change to the original design in an effort to cut down the number of machining operations a simpler version came to mind and a new drawing is aboveI have done away with the small shaft and O ring and replaced it with a 1/8” rubber ball this ball is made from the same material as the O ring is and makes for a better seal to./media/tinymce_upload/85525898e5927568b8f2f6439c4d8fe0.jpgThe parts for the new valve are basically the same but I might fit an O ring between the 2 halves to give a gas tight seal but on tests it worked well might try a shorter spring for less pressure on the ball.As said its all in aid of stopping the oil being drawn into the supper heater and there by extending the life of the engine and supper heater.I hope to move back onto the Tank engine now? Link to comment Share on other sites More sharing options...
gowest Posted October 7, 2019 Author Share Posted October 7, 2019 /media/tinymce_upload/466f8e420530f422380001c98b0b584d.JPGThe connecting rods from the A3 were to long because the cylinders were now nearer the first set of drivers and so were shortened by about 8 mm this was achieved by cutting a section of the rod out at the small end and then filing halfway into the rod on the front side./media/tinymce_upload/132f7ce544175eb6603327c85bf1e91c.JPGNext carrying the same operation but this time on the back of the main rod.A spliced joint can then be made and when soldered together it is hard to detect the join.I could have used the rods in the engine kit but these are very thin and alright if the kit has an electric motor as they are just for show but the power from the piston on the rods to the wheels on a steam engine models would soon wear out or even buckle as they do not look strong enough to take the loads./media/tinymce_upload/15d53241899f449210f1fd8765671f10.JPGWith the rods sorted out next was some crank pins these were machined up from some stainless steel and had an external thread of 1.8 mm to mach the wheels and an internal thread of 1.2 mm for the Hornby hex screw which holds the con rods in place. There was no need for the two flats that the A3 engines have for the valve gear as the GWR tank engine had its valve gear between the frames so saved a job all round.All the above parts were fitted to the engine the wheels were quartered and it was time to see if it would run on compressed air./media/tinymce_upload/1b343f0eb943a4104df43e6ad51a39d9.jpgWith the supper heater removed I fitted my compressed are adaptor to the top of the valve unit and connected a tube to this which intern connects to my small air compressor which runs at 20 psi. A quick oil up of all moving parts and switch on the air compressor and turning the wheels slowly things started to move a bit lumpy at first but with each run things got a little better as the bearings and rods loosened up./media/tinymce_upload/b32b4b2c5318defa96124cfae1d6302f.jpghere it is running but the camera and flash has stopped the motion A steam test would be the next step but I need to finish the servo unit supper heater and the electronics before that happens. Link to comment Share on other sites More sharing options...
Rog RJ Posted October 7, 2019 Share Posted October 7, 2019 Well done Ken. As always, i'm extremely impressed by your building skills and problem solving abilities. Link to comment Share on other sites More sharing options...
96RAF Posted October 7, 2019 Share Posted October 7, 2019 Total masterclass Ken. Model railways plus model engineering. Link to comment Share on other sites More sharing options...
gowest Posted October 7, 2019 Author Share Posted October 7, 2019 Thanks both for the kind words its when you see the thing running you feel you are getting somewhere once when building my GWR 1442 tank engine in 7.25 gauge and at the same stage as above with a much bigger air compressor I was eager to see the wheels and motion running and as I turned the tight wheels much the same way as above the wheels would only make half a revolution before they stopped dead at a tight spot so rushing and turning the wheels faster I managed to leave one of my fingers between the spokes on the driving wheel and as the connecting rod came round the guillotine type action almost took the end off one of my fingers and spent time up the hospital while the put it all back together much safer with 00 gauge wheels.ken Link to comment Share on other sites More sharing options...
gowest Posted October 7, 2019 Author Share Posted October 7, 2019 just a little video of the chassis running Link to comment Share on other sites More sharing options...
96RAF Posted October 8, 2019 Share Posted October 8, 2019 Very nice Ken...and this was the engine you thought might be impossible. Link to comment Share on other sites More sharing options...
gowest Posted October 9, 2019 Author Share Posted October 9, 2019 Hi Robi still have to shoehorn these parts into the small body and make it work but as you say it is looking more likely to work but having said that now something is bound to go wrong.ken Link to comment Share on other sites More sharing options...
96RAF Posted October 9, 2019 Share Posted October 9, 2019 I call it the Murray Walker effect. He could give a dead cert the kiss of death every time when commentating, bless him. Link to comment Share on other sites More sharing options...
gowest Posted October 9, 2019 Author Share Posted October 9, 2019 Yes a comantator that thought he had it right and then it all went wrong and that's why I said what I said as that's what tends to happen to me every time don't speak to soon? Link to comment Share on other sites More sharing options...
gowest Posted October 11, 2019 Author Share Posted October 11, 2019 /media/tinymce_upload/b22c28f61752dac43878a442c87e611c.jpgI tend to try the chassis in the body each time I add a part or change a part to the engine just to make sure that the new engine assembly will all fit inside without catching on any of the body sections inside the body.The first picture here shows the chassis fitted into the brass body and a check shows all is well and the chassis will go in and out with out any parts rubbing or jamming on the body./media/tinymce_upload/9b2bf4632d4a0588826a3ae395c1d084.JPGEven looking in the front with the smoke box door not fitted yet you can see that the oil tank and the oil tank pressure switch fit snugly right up to the front of the front face of the smoke box./media/tinymce_upload/642f99d7a0aa6e324012fd1bcfdec16b.JPGNow looking at the chassis with the body removed you can see that I have added a few more parts to the engine the servo unit and motor are complete and tested and all turns with out any problems.The supper heater and its heater are fitted and do not leave a very large gap between the end of the heater and the servo unit so hope all will be ok.The whistle is in place and had no changes just to bend the fixing bracket so that it picked up on one of the servo screws./media/tinymce_upload/d6bd4cf9d09c1da3f2e81648b6fba921.jpgOn the other side of the engine the only new part here was the regulator arm from the servo to the regulator lever under the supper heater.The stainless steel rod of the arm was cut down by about 5 mm and the end bent into a right angle this was because the complete cylinder assembly was now nearer the first front driver but the point at which the valve gear starts from the middle driving axle was still the same as it would have been on the Flying Scotsman engine./media/tinymce_upload/c6f565371af00caf29e36be10d957adf.jpgWhen I was fitting the electric motor into the servo unit some time before this I had sent off for a new SSR or solid state relay.This had arrived today and I wanted to see if it was going to work with this electric and if tests proved it capable of switching the motor on and off my new PCB could include this as part of the new build.This SSR was one of the smallest I had seen so far and its switching ability was 60 volts at 1.1 amps.Here you can see a lash up just to see how it might worked and the SSR is the little black square on the end of the yellow wire. Next to it is the Hornby servo drive PCB with its standard relay for comparison and again in close up./media/tinymce_upload/df4c8d5f88a9caeb25e42c6eaa50bc19.jpgOf cause once built into the engine with the heat it may just pack up but more testing will be needed to be carried out long before that stage. Link to comment Share on other sites More sharing options...
96RAF Posted October 11, 2019 Share Posted October 11, 2019 Handy bit of kit that SSR Ken, with good current capacity. Could be usefull for all sorts of things, including shrinking my points relay board, which currently is a 3 ft long plank mounting 4 x acc decoders and 32 x car relays to run 16 points. I could probably get that down to A4 size max. Link to comment Share on other sites More sharing options...
gowest Posted October 11, 2019 Author Share Posted October 11, 2019 Hi Robthey are quite good little devices I thought about trying this one as it's a little smaller than the type I have been using which is in most of my rebuilt live steam locos and can handle 2 amps and as such i have not had one burn out due to the electric motor stalling and just tripping the controller.how this new type will stand up to the very hostile environment we will see I just need to build the PCB and see if it coughs it's socks up then I can switch to the old type that I know works fine and all I've lost is time and £5.ken Link to comment Share on other sites More sharing options...
gowest Posted October 14, 2019 Author Share Posted October 14, 2019 /media/tinymce_upload/4dd18a04829ecbaa53c1059e3deda05a.jpgThe test printed boards were made up and the motor control PCB was over size to fit properly into the chassis as I wanted so a new lay out of the components will be looked into as until this part is satisfactory completed the boiler cannot be built./media/tinymce_upload/54cc932fe5ded95a54337833bc303e82.jpgYou can see here what I mean the printed board should just be flat at the bottom of the square aperture not on its side so a change will be needed here. As for the SSR tests using the Hornby controller showed it to be ok at driving the Hornby motor and all the gears and regulator rod worked fine with no over heating of the SSR could be detected but again time will tell./media/tinymce_upload/74f1dac3f6a81f96d56fd095a319abcb.jpgThe indicator light might be alright and fitted as expected the picture here is of a test model and it is going to be replaced with a better built PC later. Its just a simple power supply built on one side and the 2 colour LED on the other side./media/tinymce_upload/f339c7cf607d74c626ad46a3bfe55e0f.jpg Link to comment Share on other sites More sharing options...
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