Nibco Globe Valve issue

A special section just for steam engines and boilers, as without these you may as well fit a sail.
User avatar
cyberbadger
Full Steam Ahead
Full Steam Ahead
Posts: 1123
Joined: Thu Nov 07, 2013 9:16 pm
Boat Name: SL Nyitra
Location: Northeast Ohio, USA

Nibco Globe Valve issue

Post by cyberbadger » Sun Jul 09, 2017 6:06 am

8231054-23b.jpg
Nibco-Globe-Valve-Bronze-Class-300-1/2"
8231054-23b.jpg (36.18 KiB) Viewed 8365 times
I use one of these 1/2" NPT Bronze Nibco globe valve - Class 300 (My mawp is 200psi) as my engine throttle. The inlet for the Toledo is 1/2" NPT.

I learned the value of having an main steam walve plus throttle again. The main steam walve is an Apollo 1/2" NPT 1/4 Turn Class 250 Bronze Ball Valve closest to the boiler.

I have twice now gotten into a condition that I am not happy about with the nibco...

I find that the steam hose has filled with condensate, and the nibco valve is sputtering and can't be turned properly and seems to be oozing water.

Luckily I had the isolation valve upstream, so I turned off the main steam walve - opened the engine petcocks and carefully took apart the valve and readjusted the position of the valve shaft which is a male thread inside of the valve steam and put it back together.

What I find is that the actual plunger of the globe valve has unscrewed from the end of the valve stem.

Why is this happening and what can be done to fix it? I don't like this happening - it left me dead in the water until it was repaired - 5 minutes. Plus I don't like messing with valves, even with an isolation up stream, when under steam.

Is this a job for a specific formalization of locktite/retaining compound?

-CB
User avatar
DetroiTug
Full Steam Ahead
Full Steam Ahead
Posts: 1863
Joined: Fri Nov 27, 2009 5:56 pm
Boat Name: Iron Chief
Location: Northwest Detroit

Re: Nibco Globe Valve issue

Post by DetroiTug » Sun Jul 09, 2017 3:55 pm

Sounds like the Nibco valves need to be replaced and avoided. I think Nibco is all Chinese made. I use Apollo steam rated ball valves for throttle valves on the tug and the car and never an issue. Apollo valves are made in the USA by Conbraco.

Some "steam rated" valves are not so good. United brass makes a spring loaded check valve with Teflon seat, supposedly steam rated etc. Both of the ones I encountered did not seat reliably. One on my tug and another on a friends boat. The best check valve I've found is the stainless bodied Apollo softseat check for hydraulic service. Cured my feedpump issues on both tug and car.

-Ron
User avatar
Lopez Mike
Full Steam Ahead
Full Steam Ahead
Posts: 1903
Joined: Wed Dec 07, 2011 6:41 am
Boat Name: S.L. Spiffy
Location: Lopez Island, Washington State, USA

Re: Nibco Globe Valve issue

Post by Lopez Mike » Mon Jul 10, 2017 6:10 am

I use a quarter turn ball valve that is 150 wsp rated. I got it at Harbor Freight, a Chinese goods tool outlet chain for less than $5. It has been in use for years with no real problems. I don't find that it is at all too quick of a response on opening.

The only change I intend to make is to fabricate a new handle for it as the old one was just cad plated and is getting rusty. I have had to snug up the shaft packing a couple of times over the years.
If you think you are too small to make a difference, try sleeping with a mosquito.
Dalai Lama
RGSP
Full Steam Ahead
Full Steam Ahead
Posts: 246
Joined: Mon Dec 14, 2015 2:12 pm
Boat Name: Platypus, Shelduck
Location: Very eastern England

Re: Nibco Globe Valve issue

Post by RGSP » Mon Jul 10, 2017 9:31 am

Cyberbadger's original question hasn't been answered: why is the valve head unscrewing?

I don't know the answer, but when a globe valve stem has an external thread, and the head screws onto it, there is usually a locknut or the screwed stem has it's end rivetted over. It doesn't sound as though CB's valve has any locking mechanism, but is otherwise satisfactory and might be worth a little work to make it so.

Loctite might be an answer, but it would be working above its rated temperature, and might fail causing something like the original problem. Or might not. Given that the other valve exists in an emergency, it might be worth a try.

Otherwise what is the material of the valve head and what temperature will it take? Silver solder might be an answer. If that isn't possible, some locking mechanism is still required, so what about a 1/16th inch hole (or preferably slightly less) through the screwed parts of both stem and head, ends slightly countersunk, and a pin inserted with ends rivetted into the countersinks?
User avatar
DetroiTug
Full Steam Ahead
Full Steam Ahead
Posts: 1863
Joined: Fri Nov 27, 2009 5:56 pm
Boat Name: Iron Chief
Location: Northwest Detroit

Re: Nibco Globe Valve issue

Post by DetroiTug » Mon Jul 10, 2017 12:47 pm

Quote: "Cyberbadger's original question hasn't been answered: why is the valve head unscrewing?"

When we stipulate and pay more for "steam rated" accessories, it is the manufacturers responsibility to issue a working trouble free product, not a project. Should need no further engineering and should provide trouble free service under normal circumstances. He said he has had the same issue with two different Nibco valves - becoming inoperable in service requiring dismantling and repair. That is unacceptable and he should try to return them for a refund, or at the very least avoid that brand of valve and go with something proven reliable. His question was really answered, replace them.


-Ron
User avatar
Lopez Mike
Full Steam Ahead
Full Steam Ahead
Posts: 1903
Joined: Wed Dec 07, 2011 6:41 am
Boat Name: S.L. Spiffy
Location: Lopez Island, Washington State, USA

Re: Nibco Globe Valve issue

Post by Lopez Mike » Mon Jul 10, 2017 2:19 pm

Yeah. I agree. Dump them before he gets hurt dealing with them when they are hot and under pressure. Especially with an application like the throttle where he might hit the dock!

I've had a poppet type valve fail once with the center of the head breaking out and leaving just a ring including the valve face. This was on a full sized valve that had been in service since the locomotive was built in 1929.

There must be some limit to how cheaply something can be built but they haven't found it yet.
If you think you are too small to make a difference, try sleeping with a mosquito.
Dalai Lama
RGSP
Full Steam Ahead
Full Steam Ahead
Posts: 246
Joined: Mon Dec 14, 2015 2:12 pm
Boat Name: Platypus, Shelduck
Location: Very eastern England

Re: Nibco Globe Valve issue

Post by RGSP » Tue Jul 11, 2017 8:46 am

I don't think Nibco is one of the brands easily available in the UK, but I certainly agree that they sound well worth avoiding, and I'd certainly buy another brand myself. However, Cyberbadger did ask for a way to fix the existing valve: maybe there isn't one, in which case buying something better is the only answer. It's still a question of rather more than academic interest to know why the existing valve failed, and if it could be repaired or modified. The good quarter-turn valve in line with it does not completely eliminate any risk, but it does reduce it a lot, and if Cyberbadger wants to play with his existing valve, as long as he's careful and aware of the risks, I don't see why he shouldn't.
User avatar
Lopez Mike
Full Steam Ahead
Full Steam Ahead
Posts: 1903
Joined: Wed Dec 07, 2011 6:41 am
Boat Name: S.L. Spiffy
Location: Lopez Island, Washington State, USA

Re: Nibco Globe Valve issue

Post by Lopez Mike » Tue Jul 11, 2017 8:54 am

Yes and no.

Yes, that finding out why something failed and fixing it right is praiseworthy. I enjoy it sometimes

No, that two failures tells me that it is either a bad design or assembled poorly.

Myself I have a large list of things I want to do on my boat and spending more than a few minutes reverse engineering a cheap item seems like a lot of trouble.

Be careful, have fun and don't follow me too close!
If you think you are too small to make a difference, try sleeping with a mosquito.
Dalai Lama
User avatar
cyberbadger
Full Steam Ahead
Full Steam Ahead
Posts: 1123
Joined: Thu Nov 07, 2013 9:16 pm
Boat Name: SL Nyitra
Location: Northeast Ohio, USA

Re: Nibco Globe Valve issue

Post by cyberbadger » Tue Jul 11, 2017 4:20 pm

Lopez Mike wrote: Yes, that finding out why something failed and fixing it right is praiseworthy. I enjoy it sometimes

No, that two failures tells me that it is either a bad design or assembled poorly.
Ahh, but you are forgetting user error.

My wrist may not be properly calibrated.

Since no one here seemed to be answering my actual question I tried the smokstak because these are the same kind of valves the traction engine folks use.

Some one suggested I maybe be tightening down too much hot vs cold. I'm going to try to monitor myself next time I'm out.

Pete Labelle:
"Maybe its a function of how hard you are tightening up the valve to close it, or seating it while hot, then trying to loosen it when cold, resulting in more turning force on the contact point in the valve. "
https://www.smokstak.com/forum/showthre ... 1&t=170051

-CB


-CB
User avatar
Lopez Mike
Full Steam Ahead
Full Steam Ahead
Posts: 1903
Joined: Wed Dec 07, 2011 6:41 am
Boat Name: S.L. Spiffy
Location: Lopez Island, Washington State, USA

Re: Nibco Globe Valve issue

Post by Lopez Mike » Tue Jul 11, 2017 5:33 pm

Any valve that has to be treated so carefully is, by definition, a bad design. I'd throw them out.
If you think you are too small to make a difference, try sleeping with a mosquito.
Dalai Lama
Post Reply