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Re: Nibco Globe Valve issue

Posted: Wed Jul 12, 2017 8:28 pm
by DetroiTug
Whatever works I guess..

-Ron

Re: Nibco Globe Valve issue

Posted: Wed Jul 12, 2017 11:08 pm
by cyberbadger
One point I forgot to mention...

Stephenson linkage - much better then IC engine for stopping and reversal IMHO.

Especially if it's that quick type of response - you may get from a 1/4 valve. I go for the Stephenson linkage and put it in the center.

-CB

Re: Nibco Globe Valve issue

Posted: Sat Jul 15, 2017 6:03 am
by cyberbadger
And I ended up thinking about what you guys said and am getting a new Milwaukee Globe Valve.

You are right the current one has proved it will fail.

This milwaukee is usa made and vetted by some traction engine folk on smokstak.

Yes and several folks there think I should use a quick acting valve, but oh well I'm stubborn.

-CB

Re: Nibco Globe Valve issue

Posted: Sat Jul 15, 2017 8:19 am
by Mike Rometer
We've been using ball valves for regulators on locos for donkeys years. They are reliable and don't open/close too quickly, unless you want them to. Since I fitted the first one I wouldn't consider anything else (as long as there's room for one)
Regulator (600 x 450).jpg
Regulator (600 x 450).jpg (63.02 KiB) Viewed 7331 times

Re: Nibco Globe Valve issue

Posted: Sun Jul 16, 2017 6:57 am
by RGSP
I wrote a post here a couple of days ago, but it seems to have disappeared into cyberspace without going near Cyberbadger....

Firstly, I think you're wise to get a new valve: the cost compared with the total ownership cost for a steamboat is negligible, and you'd never completely trust the old valve.

By the way, was one valve re-assembled properly, and then failed the same way, or did two valves fail?

While steaming on Saturday, I noticed that the effective control range of my globe valve throttle was only about half a turn: not that much more than a ball valve. If the latter were fitted with a longer operating handle, control could be just as fine as a globe valve.

Re: Nibco Globe Valve issue

Posted: Mon Jul 17, 2017 10:59 pm
by superscifi12
A globe valve is the only accepted valve for throttling. All other valves will be damaged over time or after one use depending. IMO I've seen too many "Steam Rated" ball valves fail, in a system I am tasked to fix they go in the scrap pile even if they are still working and replaced with the appropriate valve, either gate or globe depending on the application. We use Apollo Valves here.

I am a Steamfitter and work on large steam systems that run all day everyday. I've worked with pressures from 5psi to 175psi and pipe/valve sizes from 1/4" to 20"

Re: Nibco Globe Valve issue

Posted: Tue Jul 18, 2017 12:17 am
by Lopez Mike
My experience has been a little different. I have five years of steaming with this cheap assed Harbor Freight ball valve in throttle duty and all if had to do so far is snug up the packing twice. The stamped cad plated handle is getting a little rough looking so I'll probably clean and paint it and make a fancy wood cover over it.

I have a couple more like it as shutoff/isolation valves for feed water and a big 1 1/2" one in blowdown duty. The big one takes a good pull to move after sitting all day (sometimes longer, cough, cough).

Granted this is pretty low stress duty. A 1/2" valve at a maximum temp of 330 F or thereabouts. If it acts up I'll be the first to let you all know.

Re: Nibco Globe Valve issue

Posted: Tue Jul 18, 2017 6:43 am
by dampfspieler
Hello,

i have built a special D-Slide-valve as blow-down-valve for one of my model-loco-boilers. It works well. You can buy it from different suppliers.

Image

Image

Dietrich

Re: Nibco Globe Valve issue

Posted: Tue Jul 18, 2017 12:05 pm
by DetroiTug
Quote: "My experience has been a little different."

With steam rated Apollo ball valves, mine too. Of course, compared to a stationary plant it's two different types of service. One intermittent and the other continual. On the Tug the steam oiler is situated before the ball valve throttle so it is continually lubricated, on my steam car it is not. Original throttle valves for steam vehicle service were an array of fast-acting slide valve designs.

The only ball valves I've seen fail in (our) steam throttle service were those not rated for steam, the seats and/or packing could not take the temperature.

In stationary plant service maybe globe valves are the only acceptable type for throttling, but for my steam car application and high output marine plants it would be a very bad set up. My car will take off like a jack rabbit and hit 40 mph no problem at all. Would be very dangerous.



-Ron

Re: Nibco Globe Valve issue

Posted: Tue Jul 18, 2017 1:24 pm
by Lopez Mike
I use one of those blowdown valves on my locomotive too. They look just like the full sized prototype and work well.