Hi green twin
In my engines case
How is the d valve attached to rhe rod?
On the pic you got threads and nuts
I got a blank round.
Regards chris
Mystery steam engine
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In my engines case
How is the d valve attached to rhe rod?
On the pic you got threads and nuts
I got a blank round.
Regards chris
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The diameter are maybe 5 mm
I try to get a better print
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Thats about all i get
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Or possibly an oiler? - Or more likely an independent steam feed - which can be used for starting if the HP cylinder is at TDC/BDC? - using a steam valve akin to a Whistle valve (Normally closed, open only when operated momentarily)?
Yes I was thinking a Simpling valve, it's on the right side to tee off the incoming main steam feed.
Too high to be used to drain the valve chest
I'll have alook at those holes in the side of the piston valve chest.
I think I said earlier that it looked like the engine may not have been finished and that is wht the rods are not threded though some people do use grub screws to set the valve nut positions. The other thing that needs to be taken into account is that you can't get to the bottom of the valve so won't have access to any nuts to adjust the valve position, it will all need to be done from the top. That is why I have not spent time detailing the outer face of the valve.
Charles or K2 what do you think of the suggested slide valve designs, The main difference is Greentwin's has a smaller cavity so will open to exhaust a lot later than mine
Too high to be used to drain the valve chest
I'll have alook at those holes in the side of the piston valve chest.
I think I said earlier that it looked like the engine may not have been finished and that is wht the rods are not threded though some people do use grub screws to set the valve nut positions. The other thing that needs to be taken into account is that you can't get to the bottom of the valve so won't have access to any nuts to adjust the valve position, it will all need to be done from the top. That is why I have not spent time detailing the outer face of the valve.
Charles or K2 what do you think of the suggested slide valve designs, The main difference is Greentwin's has a smaller cavity so will open to exhaust a lot later than mine
Opening to exhaust late normally means back-pressure, loss of performance, etc. but on a compound... I don't know?? - If the piston has nearly reached the end of stroke, or even 10~or so degrees after BDC,,, then it is probably OK? Compounds do benefit from condensers and condenser condensate pumps that develop a vacuum on the exhaust. If the HP cylinder gets (say) 15psi, the LP cylinder may be getting 5psi or less. So may be more sensitive to back-pressure?
On the compound I regularly run, it starts "cold" - but warmed as the boiler pressure is rising, being barred until the engine decides there has been enough venting of condensate that it can start running safely (2 bottom drain s open, and top auto-drains working!). When it starts to kick, the boiler has usually reached around 10psi, but the engine really only develops a secure idle when it gets between 15 & 20psi... and it isn't venting much condensate. Then after a few more (5~10?) minutes of idling, it suddenly picks-up speed as the secondary cylinder clears its throat and starts to do some real work. At that point the steam supply can be turned down (usually boiler around 20psi, but throttled by the supply valve), or burner turned down so the supply is less than 15psi. 10 psi is adequate when the engine is off-load and well oiled, hot and running sweetly. Personally, I try and run at a turned-down burner, reduced boiler pressure and wide throttle. But a colleague runs the engine "on the throttle" (He is an OO-gauge electric motor powered train driver), when he maintains maybe 5psi over the required pressure. This (he says) means he doesn't lose pressure when he has to pump cold water into the boiler, which he does less frequently than I do. Or rather he tolerates the 5 psi drop of pressure and opens the throttle to keep the engine idling. I tend to give a single stroke of the feed pump every few minutes, rather than waiting for the boiler to be nearly empty, then pumping like Billy-O to fill the boiler!.
(N.B. Thanks for teaching that it is a "simpling" valve... I.E. it makes the engine a "simple-expansion" engine on the LP cylinder for starting, rather than being a compound!).
K2
On the compound I regularly run, it starts "cold" - but warmed as the boiler pressure is rising, being barred until the engine decides there has been enough venting of condensate that it can start running safely (2 bottom drain s open, and top auto-drains working!). When it starts to kick, the boiler has usually reached around 10psi, but the engine really only develops a secure idle when it gets between 15 & 20psi... and it isn't venting much condensate. Then after a few more (5~10?) minutes of idling, it suddenly picks-up speed as the secondary cylinder clears its throat and starts to do some real work. At that point the steam supply can be turned down (usually boiler around 20psi, but throttled by the supply valve), or burner turned down so the supply is less than 15psi. 10 psi is adequate when the engine is off-load and well oiled, hot and running sweetly. Personally, I try and run at a turned-down burner, reduced boiler pressure and wide throttle. But a colleague runs the engine "on the throttle" (He is an OO-gauge electric motor powered train driver), when he maintains maybe 5psi over the required pressure. This (he says) means he doesn't lose pressure when he has to pump cold water into the boiler, which he does less frequently than I do. Or rather he tolerates the 5 psi drop of pressure and opens the throttle to keep the engine idling. I tend to give a single stroke of the feed pump every few minutes, rather than waiting for the boiler to be nearly empty, then pumping like Billy-O to fill the boiler!.
(N.B. Thanks for teaching that it is a "simpling" valve... I.E. it makes the engine a "simple-expansion" engine on the LP cylinder for starting, rather than being a compound!).
K2
Given that the port locations and sizes are somewhat approximate, I think the best that can be done right now is to make an approximately sized valve that will function relatively well with the ports that are on the engine.
It is impossible to make exact statements about event timing with such inexact port information.
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It is impossible to make exact statements about event timing with such inexact port information.
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They make some couplings that are used to attach pulleys and flywheels to shafts, and they are slit several times, with an allen screw that pulls the pieces together and jams the coupling to the shaft.
I forget the name of them, but I have seen them.
Perhaps not exactly like this video, but you get the idea.
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I forget the name of them, but I have seen them.
Perhaps not exactly like this video, but you get the idea.
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Why would you want a Huco when there is no axial rotation?
Your valve cavity is very short and as K2 says will see a lot of back pressure. Infact on the scaled port face the inlet is opening before the exhaust.
Your valve cavity is very short and as K2 says will see a lot of back pressure. Infact on the scaled port face the inlet is opening before the exhaust.
Your valve is designed around asymmetrical ports and bridges.
I am not aware of a steam engine that had assymetrical ports.
Asymmetrical valves were common on large vertical engines, but the ports where symmetrical.
Using asymmetrical ports and bridges throws all the normal timing events out the window.
I did not plot out the valve travel vs the ports, since we don't know exactly what the port dimensions are.
The port dimensions should definitely not be asymmetrical, as far as anything I have ever seen in the old books.
You can't discuss exact inlet and exhaust events correctly if you don't know exactly where the port edges are.
Here is a plot for a Stanley 20hp engine.
I use displacement diagrams, as did many in the old days, and find them much easier to visualize than polar diagrams.
This displacement diagram was generated using a spreadsheet.
If we had exact port dimensions, we could punch that into a spreadsheet and get an exact idea of events.
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And this diagram from "Verbal Notes" gives a lot of information about events for a steam engine, which are admission, cutoff, release, and compression.
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