The Steamboating Forum

Has anyone come across an improvement on the traditional gland packing arrangement for piston rod and valve spindles? On prop shafts etc we now have modern lips seals etc that work very well, but of course they are rotational, rather than a sliding shaft. Has anyone come across something that will work well with a sliding shaft, and cope with steam?
Daniel

I've used solid PTFE bored and turned to a good fit as gland packing. Haven't proved the longevity to my own satisfaction yet, they haven't been run enough yet, but they work well.

I hadn't heard about the lip seals for prop shafts. The only optionsI knew about were either the traditional old packings or the Acetal plastic axial seals. There are carbon seals in use in water pumps but I haven't seen them on prop shafts.

I have used Teflon for piston and valve rod packings but they are unhappy with any surface flaws on the shafts.

There is something to be said for the old stuff. Easy to fix when something goes wrong.

Cutting a bunch of fine water grooves in the valve stem has been known to reduce the load on the packing, but for most of us our 1890's steam conditions are adequately served by 1890's solutions. That said, Teflon faucet packing is the cat's meow when it comes to long lasting and low friction sealing of
valve stems and piston rods.... but as Lopez Mike said, they need to be smooth.

You can also try stacked Viton o-rings that closely fit a traditional packing installation.

If you're running superheated steam, labyrinth water grooves + packings on the cool side might work well.

- Bart

What kind of grooves? Circumferential? Lengthwise?

Why would that help?

What REALLY works on Stanley's is hard chromed and ground rods and valve stems, maybe a bit pricey but only done once! It's ten years since I repacked with graphite packing and still good!! Be aware in the car world the packing is NOT just wrapped around the shaft; it is a series of stacked rings, end gaps NOT lining up. Easily done with a wooden dowel the same size as the shaft, packing wrapped around that and cut along the length of the dowel with a razor blade; you now have a stack of circles which then get worked into the gland, again gaps NOT lined up. Happy Packing rp

Lopez Mike wrote:What kind of grooves? Circumferential? Lengthwise?

Why would that help?

These are circumferential.

https://en.wikipedia.org/wiki/Labyrinth_seal
https://www.steamautomobile.com/wsa/tut ... dex_17.htm

- Bart

Hmm. It all sounds very good but it also looks like a recipe for a drooling mess. I'd have to see it running.

I think I'll stay with my 19th. century stuff for now.

Lopez Mike wrote:Hmm. It all sounds very good but it also looks like a recipe for a drooling mess. I'd have to see it running.

I think I'll stay with my 19th. century stuff for now.

Yup. These work very well in steam turbines where temps are high and the packing is really hard to replace.

For steam cars w/ really high temp steam, these can be used to distance the old fashioned packing far away from the high temps and
pressures.

- Bart

I stole packed rods from a pneumatic cylinder, ground and hard chromed surface. Graphite woven packings from the power plant. These rods for the main steam cylinder of the engine have been in service for 5 - 1/ 2 years now. I remember a few years ago I saw a small wisp of steam from the gland. I tightened the packing nut slightly, and never a leak since.

Besides the hard chromed and ground rod, good alignment guiding the rod in a straight line is important.