Cylinder taps

[BOB BLACKSHAW 1Participant @bobblackshaw1]

I’ve made a few copies of the Stuart 10v from bar stock, the latest one I made the reversing gear and decided to put taps on the cylinder. I made the taps with 2mm holes in the cylinder, with 3.5mm threads for the taps. This must be a daft question or I’ve done it wrong but what is the point of taps on cylinders when you have the exhaust. I know the idea is to drain the cylinder of moisture, but pointless on mine. It looks good anyway.

Thanks Bob

[bernard towersParticipant @bernardtowers37738]

To stop the possibility of hydraulic locking with the condensate.

[Clive Brown 1Participant @clivebrown1]

Perhaps not a lot of practical use with slide valves that can lift off the valve face to expel condensate. Necessary with piston valves to avoid condensate being trapped at the ends of the piston stroke, with possible consequent damage.

[bernard towersParticipant @bernardtowers37738]

Surely the valve can only lift if a port is open what happens when they are not open?

[JasonBModerator @jasonb]

If they are not open then your piston is not compressing any liquid anyway so nothing to worry about, port should be open on the exhaust part of the stroke. Even if you have  alot of lead so the port closes before the piston reaches the end of the cylinder by having the slide valve able to lift that will “open” it to exhaust.

You can also open the drain cocks and run some steam through the cylinder to warm it and drive any condensate out of the feed pipe. In the case of a coal fired boiler you won’t get the condensate going through the exhaust and into the chimney where it can run back down into the fire, just goes to where ever you have the cocks plumbed to.

[Author]

Posts