The Home Machinist!

I made a set of steam-operated cylinder drains for my American this winter only to find that my pressure/vent valve leaks like a sieve!

(It applies pressure to hold the drains closed and vents to atmosphere to drain.)

Does anybody know who makes pressure/vent valves? (Preferably in 1/4-40)

Adding to this does anyone make a push/pull 3 way Cyl cock valve?

Superscale did. Part no. 12-04. Perhaps you can find one somewhere.

You could take a regular globe or angle valve and drill out the threads in the bonnet. Then plumb it up with steam on top of the valve stem rather than under so steam holds it shut.

Wayne Godshall has push/pull valves for cylinder cocks. Call American model engineers. 717-275-3273
I have two of them.

Pardon my ignorance but I thought the push pull valves were for the injectors, which want a quick jolt of steam to get them started.

The cylinder cocks should need nothing more complicated than a steam gate or globe valve, steam on or off. Quick opening or closing is not required, just properly sealing.

Maybe I’m off my nut.

Brian

makinsmoke wrote: ↑Tue Apr 23, 2019 10:40 pmThe cylinder cocks should need nothing more complicated than a steam gate or globe valve, steam on or off. Quick opening or closing is not required, just properly sealing. Maybe I’m off my nut.

No, you are not 'off your nut.

For steam-operated drains, they need to apply boiler pressure to the line in one position and vent the line to atmosphere in the other position. So it isn't just an "off/on" but a "vent/on".

You need a 3 way valve.

I had a superscale three way valve on the ten wheeler and i have to tell ya, i was not impressed with the lack of reaction time opening the drains.
a low cost solution out be to use a standard valve in the cab and to create a drain cock out of a piece of brass and a pointed setscrew.
using the setscrew as a needle valve in the brass body. you will be able to dial it down to a slow controlled leak. it will also keep the condensate out of the line leading to a faster response. put this assembly at the end of the line, just a thought

I just plumbed in 2 valves. One allows steam to the line and cylinder cocks and the other vents that line to the atmosphere. Quick acting and just looks like one more valve on the manifold. Not prototype, but functional. You just have to close one then the other and then reverse the process to open or close.

Hi,

The simple way is to make a small ball check valve with no closing spring and Install the valve on its side at the low point in the piping.

This way, steam pressure will push the ball into position to close the little check valve and when the steam supply valve is closed, gravity will pull the ball to the side and open the valve after the condensing steam relieves the pressure in the piping. This will allow the lines to drain until the next time you want the drain valves closed.

You can also check out the Clippard company. I'm pretty sure they make small 3 way valves that are inexpensive.

KISS (Keep It Simple, Stupid) is always alive and well if you give it some thought!

Just my two cents for what its worth.

Richard Trounce.