air brakes on the 2.5" scale consolidation

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Mike Walsh
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Location: St. Louis, MO

Re: air brakes on the 2.5" scale consolidation

Post by Mike Walsh »

What did you use for a governor? You said it will cycle every so often to keep the cylinders warm and lubricated.

If all else fails, on my application, I'm inclined to develop a simple low-current circuit that will have an air pressure sensor and an electrically operated solenoid valve. The idea will be to wire in a timer circuit to cycle the pump a few times every so often to keep things warm and lubricated.

On the flip side, I have graphite teflon rings in my pump (both on air and steam sides) so lubrication requirements would be minimal...
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JessVanWinkle
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Location: Iowa

Re: air brakes on the 2.5" scale consolidation

Post by JessVanWinkle »

The pump will always have have a supply of steam from the hydrostatic lubricator (the lubricator is feed by a 3/32 line). I am hoping that is enough to keep it from condensing up.

The governor is basically set up like full size, just spread out.

I mondified this safty valve from McMaster 50265K23 . basically closed it up and ran a 3/32 line from it up to the governor.

I didn't take any pictures of the governor disassembled. The picture is of it in place. The 1/4" line at bottom is supply steam. output to pump on the right side. Left side is from the hydrostat (passes through valve open or closed). The small line on top is from that safty valve. ( the coil seen on top is not part of this, it is for the boiler psi gauge)

When the safty opens the top line is charged, this pushes down a small spool typ valve and closes an oring seat shutting off the steam supply. When resevour psi goes down the safty closes and the pressure bleeds off the top chamber, and supply pressure opens the valve again. there is a vent opening between the steam and air side so they cant blow by and mix.

This is the set up right now, we shall see if it works....
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cbrew
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Re: air brakes on the 2.5" scale consolidation

Post by cbrew »

JessVanWinkle wrote:The pump will always have have a supply of steam from the hydrostatic lubricator (the lubricator is feed by a 3/32 line). I am hoping that is enough to keep it from condensing up.

The governor is basically set up like full size, just spread out.

I mondified this safty valve from McMaster 50265K23 . basically closed it up and ran a 3/32 line from it up to the governor.

I didn't take any pictures of the governor disassembled. The picture is of it in place. The 1/4" line at bottom is supply steam. output to pump on the right side. Left side is from the hydrostat (passes through valve open or closed). The small line on top is from that safty valve. ( the coil seen on top is not part of this, it is for the boiler psi gauge)

When the safty opens the top line is charged, this pushes down a small spool typ valve and closes an oring seat shutting off the steam supply. When resevour psi goes down the safty closes and the pressure bleeds off the top chamber, and supply pressure opens the valve again. there is a vent opening between the steam and air side so they cant blow by and mix.

This is the set up right now, we shall see if it works....
How does the air bleed off? just a man made leak?
If it is not live steam. its not worth it.
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JessVanWinkle
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Location: Iowa

Re: air brakes on the 2.5" scale consolidation

Post by JessVanWinkle »

yes, I thought about using a needle valve to adjust the bleed off. Right now it is just the gov cover with no gasket. Seemed to work out about right.
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cbrew
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Re: air brakes on the 2.5" scale consolidation

Post by cbrew »

JessVanWinkle wrote:yes, I thought about using a needle valve to adjust the bleed off. Right now it is just the gov cover with no gasket. Seemed to work out about right.
sounds logical. I just put that safety valve on my next order,

there is still one little bit of fogginess, i know the output from the safety is controlling the steam valve. is it just a simple cylinder?
that is what i see in my minds eye.
If it is not live steam. its not worth it.
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JessVanWinkle
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Location: Iowa

Re: air brakes on the 2.5" scale consolidation

Post by JessVanWinkle »

Yep, I made the air side 5/8" dia the steam end is 3/8" and the sealing oring is 5/16"

pictured is an earlier version when I thought air psi would be a little higher and made the air and steam side the same size. I was going to use a helper spring on the air side to help overcome the higher pressure on the steam side, but that didn't seem to work well.
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redneckalbertan
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Re: air brakes on the 2.5" scale consolidation

Post by redneckalbertan »

A question about your governor, what air pressure does it shut off at?
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JessVanWinkle
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Location: Iowa

Re: air brakes on the 2.5" scale consolidation

Post by JessVanWinkle »

redneckalbertan wrote:A question about your governor, what air pressure does it shut off at?

It is set at about 90 psi right now. seems to open again around 70psi.
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cbrew
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Re: air brakes on the 2.5" scale consolidation

Post by cbrew »

Thank you for the info, I will be building one of these soon. tho i will need to lower the pressures just a little..

i wonder if you remove the oring that closes the stem port for the metal to metal seat can leak a little, that would allow the pump to cycle enough to keep everything hot. (just thinking a little (yeah i know, dangerous this early ))

for the sake of size, I under if one of these (or make one) can be used
http://www.pmmodelengines.com/shop/boil ... ety-valve/

I really like your idea of using a safety valve to control the steam valve . very clever!
If it is not live steam. its not worth it.
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JessVanWinkle
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Location: Iowa

Re: air brakes on the 2.5" scale consolidation

Post by JessVanWinkle »

thank you,
I am eager to see if it works in real use.

I am sure there is plenty of room for improvement!
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cbrew
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Re: air brakes on the 2.5" scale consolidation

Post by cbrew »

do you have a shot of the safety valve so i can see what changes you made to it?
THanks
If it is not live steam. its not worth it.
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JessVanWinkle
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Joined: Sat Mar 01, 2003 9:54 am
Location: Iowa

Re: air brakes on the 2.5" scale consolidation

Post by JessVanWinkle »

I turned down and threaded mine to 1/8NPT.
Threaded and plugged the top and soldered plugs into the side openings, one plug is tapped for the output.
I made a gasket for under the locking nut, and used thread sealant on the threads for the adjustment.
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