Simpling Valve

wsmcycle · Post by **wsmcycle** » Thu Apr 23, 2015 1:01 pm

I have read so many things on this forum and others about a simpling valve. Can someone please make an explanation of its function on my two cylinder compound engine? I include a picture with a circle on it. Is that what this is? I ran without messing with it. I cannot find an explanation or description of the components on the engine but this is the only valve I cannot identify.
Thanks
Wendell

DetroiTug · Post by **DetroiTug** » Thu Apr 23, 2015 1:42 pm

Not sure what that is in the pic. A simpling valve makes a compound self starting from any rotational position of the crank. Open that valve, and if it starts anywhere, or close it and it won't, thats what it is. And it must use some sort of internal porting inside the cylinder casting. Generally a simpling valve is piped up externally.

-Ron

wsmcycle · Post by **wsmcycle** » Thu Apr 23, 2015 2:13 pm

I really enjoyed the plethora of pix you put on the photobucket page. I am going to have to figure out how to make one of those pages. The more pix, the more you learn. Do you know where to buy the brass stanchions for those low deck rails?
Thanks

Akitene · Post by **Akitene** » Thu Apr 23, 2015 3:25 pm

Hi Wendell,

A simpling valve temporarily turns a multiple expansion steam engine into a simple one by directly admitting high pressure steam to a lower pressure cylinder - hence the name. In a compound steam engine, the simpling valve directly admits steam to the low pressure cylinder which is in mid-stroke when the high pressure one is stuck at top or bottom.

One would point out that a simpling valve is not effective with compound engines that have opposite crankshafts (a few compound engines have a 180° crankshaft).

Hope this helps.

Christophe

Lopez Mike · Post by **Lopez Mike** » Thu Apr 23, 2015 5:49 pm

There's enough leakage on many small compounds that they will reverse or start without a simpling valve. It doesn't take much as we are starting under a very small load. Unlike railroad practice where one wouldn't be able to start a train without the valve. Locomotives all too regularly find themselves admitting nearly full pressure in a stationary engine.

wsmcycle · Post by **wsmcycle** » Thu Apr 23, 2015 6:02 pm

So, here is the scenario

The HP is stuck tdc or bdc, therefore the LP is "about 90" advanced or retarded from the HP. Open the simpler valve. The introduction of the high pressure steam yo the LP. It can easily by virtue of the size of the LP piston exert enough force to move the HP up or down off of center. The simpler can only be connected to one side of the LP. Close the simpler and the HP is in a perfect move off position. Is this correct description of the process?

Wendell

Akitene · Post by **Akitene** » Thu Apr 23, 2015 6:49 pm

Yep, you get it right! It's that simple.

gondolier88 · Post by **gondolier88** » Thu Apr 23, 2015 7:29 pm

Very common practice on later compounds to put a valve seat inbetween the HP (inside admission piston valves) and the reciever (also sometimes took the form of a quarter turn plug cock with passages between the two spaces).

It was often externally piped on larger engines where longer small bore passages were presumably too difficult to cast into the blocks.

However, it's still not a simpling valve as it doesn't equalize the pressure of the LP and HP valvechests, so is a starting valve, used to warm through and aid starting when stuck on dead centres.

Greg

fredrosse · Post by **fredrosse** » Thu Apr 23, 2015 8:02 pm

"The simpler can only be connected to one side of the LP. Close the simpler and the HP is in a perfect move off position. Is this correct description of the process?"

I believe the simpler connects high pressure steam to the VALVE CHEST of the LP cylinder, and the steam valve for the LP cylinder then decides which end of the LP cylinder to pressurize, so the simpling valve flow can be connected to either side of the LP cylinder, thus starting the engine in either forward or reverse, depending on the setting of the engine's normal running valve linkage.

DetroiTug · Post by **DetroiTug** » Thu Apr 23, 2015 9:47 pm

"Do you know where to buy the brass stanchions for those low deck rails?"

Those were made in a CNC lathe. Then I drilled a .5" hole through the center of the sphere and ran a piece of 1/2" admiralty bronze rod through.

Glad you're finding the pics useful and they are serving as a resource for people interested in steam.

Here is a pic of the CAD window. You can have the drawing and G-code files if you'd like them.

-Ron

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