How to correctly grease a gate valve in line/manifold

[johnull]

Simple question, tricky to answer I guess.
How do you correctly grease a valve that is mounted on a manifold or in a process line without getting grease in the bore?
The bleeder plug is obviously a good thing, but a lot of valves do not have this, and I believe it is hard/impossible to grease it correctly without.
Even with the bleeder plug I find it hard to know exactly.
Valve fully open, and the cavity will be full of grease, meaning when you operate it the excessive amount will find its way into the gate bore, and there you go.
Same for the fully closed position, it will then fill up the bore and once you open it you'll be stuck with the grease in the bore.

Looking forward to any reply

 

[TugboatEng]

Why do you think the valve needs grease. The packing should be self-lubricating. The stem and nut may require lube but there is an air gap to the packing so there is no way for grease to get in to the process.

 

[johnull]

There is usually a couple of kg with grease in the gate valves cavity.
The reason I know about is to prevent well fluids from entering the cavity, causing lots of different problems. I.e corrosion, erosion, differential pressure (making it hard/impossible to operate)
Also aids in keeping the valve smooth to operate as it lubricates the gate that slides up and down.
Don't know what sort of gate valve you are talking about but it is required from the manufacturer to grease these sort of gate valves in order to keep operation smooth and extend the lifespan of the valve.

 

[TugboatEng]

Is this product working for you? Does it provide satisfactory life? I have never heard of using grease in the way you describe.

 

[HitokiriAoshi]

he's talking about API 6A gate valves. typically ships with grease filled cavities. I only have fundamental experience with these upstream valves, but yes, the grease is there to fill the cavity behind the drift plates to reduce the amount of media that can be trapped there causing issues.

These types of valves usually do not get lubricated in the field from my knowledge, as they usually get sent in, rebuilt, regrease, and sent back out. However, if necessary, it can be regreased through any port accessing the cavity (if one exists). If you are greasing back into the cavity, you just have a path for whatever was in those space to leave. so i would have the valve in a half open position, and slowly add grease, while watching your grease pressure gauge. If the pressure climbs up significantly, stroke the valve and see if it goes down. If not, give up trying to grease the cavity, as you could cause more harm than good.

https://pdf4pro.com/cdn/model-fc-gate-valve-service-and-operation-manual-4e9fb7.pdf

I would look up iom for the valve, or call the manufacturers for clarification.

Luke | Valve Hax |

https://valvehax.com/

 

[johnull]

I have grease a lot of valves in a manifold, but I have continuously asked myself if it is necessary or not. Depending on the grease and media flowing through I would say so that it is necessary to fill up with grease with intervals.
The easy part is to grease it when it is sent in and repaired. Done that 100s of times, no issues. But avoid getting any in the bore is just pure luck if you ask me.
Most "new" valves have a bleeder plug now, which is ok, but it doesn't eliminate the issue completely, however, it improves it drastically compared to no bleeder plug.
IF you have a bleeder plug, I would grease the valve fully open and I'd open the bleeder plug until grease starts coming out, then I would close the valve/gate. And more grease will come out the bleeder plug, "preventing" it from coming into the gate bore when closing.
Only thing I can think of as "logical". However I feel it should be improved or developed, but this is probably as good as it gets?

 

[jbeckhou]

Grease will wash thru the bore each time it is operated.

More information in our user manual.

Petrotrim Services, LLC

http://www.petrotrim.com