Boiler nonreturn valve

[PanamaSFF]

I'm new to this sight so please be patient. I have two boilers with a common header that feeds our facility, each boiler has two valves between the header and the boiler and the piping between the two valves has a small drain line with a valve. We refer to the 1st valve closest to the boiler as the "boilers isolation" valve and the second as the "non-return" valve. The non-return valves packing is leaking a lot. Is there anyway to add packing without having to do a total steam shut down? This is an old facility and I'm really concerned about what problems might come up if I do a total steam shut down. Any assistance you can give would be greatly appreciated, Thanks

 

[RVAmeche]

Are both boilers required for production or is one a spare? Is there a DBB (double block and bleed) between the active boiler steam output and the other boiler steam output?

Typically on steam systems (among others) you need a DBB to ensure you've isolated the section of the system you want to work on.

 

[PanamaSFF]

No they're both not required. Every year we have to shut one down and take it apart for inspection and we can do that by closing (locking & tagging) both the isolation and the non-return valves. We just did that and I noticed that the packing on the non-return valve wasn't leaking nearly as much as when she's online, but there was still some steam coming out. That valve has a rising stem with a chain to open and close it.

 

[LittleInch]

There is a world of difference between a "non return" or check valve and an isolation valve.

Do you have any photos or P&ID?

adding or adjusting packing on a working system is fraught with danger. Without knowledge of the valve and its packing no one can say, but I doubt anyone one will want to loosen off the packing gland to add any more to a live system.

You might be able to enclose the valve inside a pressure containment shell?



Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[PanamaSFF]

I think I have no choice but to do a total steam shut down but I thought maybe someone else would know more about the construction on a non-return valve. I'm thinking about the location of the packing gland in relationship to the disk in the valve itself. I've attached a photo and you'll notice the steam coming out of the gland. I can shut down the boiler and release all the pressure. But when I do that I still have some steam coming out of the gland, not a lot but it doesn't take a lot to hurt someone. I'm not sure if its a small amount of steam going by the valve disc seat or if the gland is on the other side of the valve disc exposing it to the pressure in the header.

 

[DBreyer]

There are specalist comapanies e.g. TEAM Furmanite that are able to do a live packing injection on most valves, even in high pressure feedwater service.

The drill a hole into the stuffing box and inject a compound which then acts as the packing.

Might be worth contacting them.

Daniel Breyer
Inspection Engineer

http://lnkd.in/dFcQA-w

 

[PanamaSFF]

That sounds great I will look onto it, thank you

 

[chicopee]

Before you follow DBreyer's advice, I would contact the insurance carrier and the legal jurisdiction on boilers and pressure vessels to be sure that they agree to the procedure by TEAM Furmanite.

 

[PanamaSFF]

That's good advise and so far I haven't been able to find anymore information on this procedure of live packing insertion is there another name for that process?

 

[racookpe1978]

If the boiler steam drum (?) is under the green insulation at the (assumed) bottom of the picture, and the shut angled globe valve (by the ladder) is actually closed, but steam is still "leaking" (blowing out) the packing of valve nbr 2, then you MUST shut off the boiler and lower temperature and pressure BEFORE working the packing. (Either by hand or by injection).

Not safe otherwise. That steam is "live" - not just simply or slowly leaking by the isolation valve, leaking through the packing, and leaking past the gland packing cover of the second (closed) valve.

 

[mk3223]

As suggested above, consult with the TEAM Furmanite for a leak seal repair. IMO, it might be workable either by the packing injection, or adding a leak seal clamp on the valve gland to temporarily stop the steam leak.

 

[davefitz]

The plant documents ( and the valve nameplate ) should define the name of the valve mfr and the valve model number, as well as the factory serial number. The mfr has published ( and likely online) procedures for intallation, operation , repair and raintenance of the valve. Sometimes it pays to read the instructions.

"...when logic, and proportion, have fallen, sloppy dead..." Grace Slick

 

[Dhurjati Sen]

Dear PanamaSFF,

Furmanite etc. are good temporary repairs, but then you cannot repair the valve in future. So, in your case, line-up the furmanite or any other temporary repair agency for the above and also initiate procurement of the NRV.

Regards.

DHURJATI SEN

https://www.nace.org/people/dhurjatisen

 

[LittleInch]

Panama,

If indeed the flow is up then what you seem to have is an angle globe valve and standard gate valve isolation.

I have no idea why this is called a non return valve.

The globe valve is there to control pressure and flow and tends not to seal 100%

You may find that the gate valve is built with a backseat function where if you open it 100% the gate seals the shaft gland.

Some people then try to claim that you can then replace / repair the gland. Most sensible and un burnt maintenance engineers will tell you otherwise, but if might reduce the steam escape. It might though also stick fully open....

Total shut down looks like your only safe method of a permanent repair.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[PanamaSFF]

Sorry for the delay in responding had a job come up. The boiler in the photo is on line and supplying steam. When I shut it down and close the valves the packing leak goes down to just a little mist of steam. I've tried back seating the valve with no luck. I forgot to mention this is a 1969 plant and we are closing down in May 2020 so my spending is being watched closely. The buildings will be demoed when we move out so of course they only want to spend enough to stay open for another year. There in lies my problem.