Nibco Globe Valve issue
- cyberbadger
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Nibco Globe Valve issue
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
- DetroiTug
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Re: Nibco Globe Valve issue
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
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
- Lopez Mike
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Re: Nibco Globe Valve issue
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.
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
Dalai Lama
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Re: Nibco Globe Valve issue
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?
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?
- DetroiTug
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Re: Nibco Globe Valve issue
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
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
- Lopez Mike
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Re: Nibco Globe Valve issue
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.
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
Dalai Lama
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Re: Nibco Globe Valve issue
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.
- Lopez Mike
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Re: Nibco Globe Valve issue
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!
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
Dalai Lama
- cyberbadger
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Re: Nibco Globe Valve issue
Ahh, but you are forgetting user error.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.
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
- Lopez Mike
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Re: Nibco Globe Valve issue
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
Dalai Lama