Packing nut fun

ChrisJ

Ok so I thought I understood how to adjust a packing nut but I'm questioning my self now.



<strong>What is the proper way to adjust a packing nut on a steam valve?</strong>



On my radiator valves I originally adjusted them so I felt resistance rocking the valve knob back and forth between open and close slightly.  I did this with the valve almost completely open.  Later on after thinking about it I went and closed the valves more, going probably 50% closed and noticed I felt no resistance.  At this point I'm assuming this was due to corrosion or whatever on the valve stem and decided I should tighten the nuts until I feel resistance at the loosest spot and then open them fully.   I've done this to all 10 radiators, but is it really the right way to do it?  



<strong>Can the proper replacement packing for these old valves be bought?</strong>

Are there any places to buy the actual proper, new packing for the old steam valves or is our only resort to use packing rope? If packing rope is the only thing we can do, what is the best way to use it? I have a new package of it and have no idea what to do with it, I remember seeing a video where the guy rapped it around the valve stem some, but left the original packing in the nut. Seems kind of odd to me but what do I know.





<strong>Whats with the packing becoming loose on my king valves?</strong>

My 1 year old gate type king valves have been driving me nuts.  The packing seems to become loose over time.  I've noticed while the header is hot the valves feel tight but when its cold they feel loose again.  Do I keep tightening!?  I've finally hit a spot after well over a year where they feel ok cold and tight when hot. It seems odd being they were rated for 600PSI steam.





Look forward to all responses good and bad!

Charlie from wmass

Do they leak?

Graphite packing thread is used to pack them. I have used thread sealent tape rolled into rope form with good luck. The packing should be sealed when the valve is in its working position, Test with soapy water if you want to be sure. Due to expansion and contraction of the metals involved they will leak after  a time. That is why they need checked. Do not get lost with it though. They will leak when they change position, it is the nature of the beast. Do not get too concerned or expect it to not leak, you will be disappointed more then not.

ChrisJ

leaking or not

Hi Charlie,

I don't know if they leak because my pressure is usually too low to tell at least by noise most of the time.  I'm suspecting they may leak during my recovery in the morning, problem is I'm in bed passed out.  I know, no excuse but at least I'm honest.   



I will try your recommended method on the next long cycle this way I know theres at least some pressure there.  I do have them pretty tight now, tight enough that it would be a real pain to open and close the valves a lot.  I didn't really care as I never use them anyway.  I'm both surprised and happy to hear they were originally packed with the rope.  So if I actually wanted to replace the packing all I would do is remove the knob, the nut and clean the old packing out and rap new rope around the stem until it was about right, and put the nut back on?  Knowing that it was actually rope and not just rubber explains how they still seal at 80 years old.  If I decide to, should I use valve grease on the stems or is this a huge no no.  I dread introducing any type of oil to the system but at the same time I don't know if that would get washed down or not?



The king valves I have seen leak when I did a blowdown at around 5 PSI but that was a rare situation and I tightened them just until they stopped.  Problem is I doubt they stayed as tight.  Perhaps new valves take time to break in with steam due to the temperature changes?  They seem to have settled down but it took many many times of tightening the nuts.

ChrisJ

How tight?

Something I think I forgot to ask is how hard should these packing nuts turn?  I was using a 12" adjustable on them and noticed at least one needed some forced to get it to budge.  I'm wondering if its simply out of adjustment and I'm pushing my luck.

Pumpguy

Packings.....

are really a primitive type of seal, just lubricated yarn or rope, really.  On a pump, some water drip is required to keep the packing soft and lubricated.  Some pumps have a perforated lantern ring in the stuffing box with rings of packing on either side.  Special packing lubricant grease is injected into this lantern ring from outside the stuffing box. 



This special packing lubricant grease is available from John Crane Co.  Also, there is a special packing lubricant called LUBALL, and is available from Crandall or Garlock. 



In a pinch, you could try smearing some waterproof bearing grease on your packings when you pack your valve stem stuffing box.



Hope this helps,



Dennis