Refurbish ball valve for natural gas 1

[Dario2002]

What are practical experiences with refurbishing welded body ball valves for natural gas?

We have some stock of leaking ball valves (PTFE seal, 12", 18", 20", Cooper Cameron, Argus, etc.). Experience with many of new valves (which often comes from China) are worse than 30 years old C.C. or Argus, and we want to save them if possible. We have some vendors which claims that they can refurbish those valves to be useful as new.

How do we ensure this so that we have reliable valve for many upcoming years? Which steps of refurbish steps to control with them, what conditions to set up, how to test refurbished valve? As I know there is API 6DR, and final testing should be as for new valve per API 6D. Is this enough?

1) What is best way to cut valve body?
2) What is best way to weld body back?
(Maybe link to some reference article, video, book, etc...)

3) Is it possible to buy complete original seat packs for old valves as defined or then need to produce some parts from scratch?

4) What are practical experiences with refurbished ball valves?


I hope to get at least some of those questions answered.
Tnx.

 

[gerhardl]

Some general advice:

1.As for the valves, the refurbishing companies vary in quality.

2.Ask some companies for preliminary offer with detailed description of method, preliminary cost and preliminary timneframe, and hourly rate if extra work in addition to described is necessary.

3. Ask for references with copy of relvant documentation, including pictures.

4. Ensure that the company really has certified welders, certified tools and instrumentation (calibrated and certified), suitaible and certified lifting tools, QA- certification.

5. Check which work the comany will buy from subsuppliers (tests, functional and pressure tests,sandbblasting, painting/protrction)

6+. Check that end-product can be supplied with all necessary tests and papers, fully qualified for todays operational requirements.

 

[zdas04]

You have valves that last for 30+ years. Buying a no-name valve saves you $15k, but must be replaced every 5 years. Did you really save anything? If you factor in the cost of the gas you have to vent to work on the damn thing how much extra did it cost?

Refurbishing a valve that has proven ineffective, seems like throwing good money after bad to me. If the seals don't work after just a few seasons, where else did they cut corners? Did they skimp on the wall thickness of the material holding the seal? Did they use pot metal to hold the packing gland nuts? It sounds to me like you may be lacquering a turd (i.e., it is now all shiny, but it is still a piece of crap).

I've never refurbished a valve or purchased a refurbished valve--the cost of the gas I have to blow down to fix a small problem makes all problems large.

David

 

[gerhardl]

zdas04. I agree, it is always safer buy a new valve at proven quality, against one of poorer quality. Cost/lifetime can be difficult to calculate, but servicecost saved, even by changing only sealings (including stop cost), can often be more than enough to give payback on a considerably higher purchasing price.

But: there are some solid and high-quality refurbishing companies out there. Even at 30 years service a high quality valve could have under circumstances only limited damages.

The catch is that you cannot know for sure the exact condition for a well-used valve before you have disassembled the whole valve.

Normally is often said that the refurbishing should not be done if it cost is more than 30% to max. 50% of the price of a new valve. Included in should be all costs, including downcost, transport and all tests.

Some high-quality factories give by refurbishing the same guarantee as for new valves, and promises the normal expected lifetime 'as new'.

If you can do the change stepwise it could be sensible to do as zdas04 says: buy first one new high-class valve. Then: take the one valve taken out to be checked for damages and cost estimation of repair at/by the selected refurbishing company.

Final decision to be taken first when results of repair cost is known and can be evaluated against price of first-class new valves. Both deals commercially negotiated to lowest price, but not for cheapest, but best constructed valves .

Note: under commercial conditions valve suppliers should both be invited to comment on construction and offer best material/best construction for the application, expected lifetime and references to be one of the evaluation criterias.

 

[Dario2002]

Regarding buying low quality products:
My intention is not to save money buying new low cost valves. However, we as company are obligated to use public tender, and cannot choose by name which valve we want to buy. Elimination level is technical specification, and second condition is lower price. On the first step (technical specification) we can define that valve should meet some criteria, and have some certificates. But on last two tenders, products from China meet all of those conditions and certificates with much lower price, and management decided to buy those (more like sample test). It is true that valves are functional for now, but some transition parts are to week and complete valve those not look reliable. I would like that I can define some technical conditions and certificates to get only best quality products, but I'm not allowed to say for some product "I think that one is not good". It must be defined with hard specification conditions (yes/no) before tendering. Demanding for API6D or similar is not enough.. what else should be conditioned? But this is probably question for another topic..

Therefore, we want to refurbish old "first class" valves (which are not damaged, just wear out and removed from unused pipelines), in HOPE that this one can be used AS NEW, and it can be better than new low cost product.

Anyhow, thank you all for inputs.. I hope to get some links for some examples, and to hear practical experiences.

 

[gerhardl]

Dario 2002:

You are quite correct, and the problem is well-known in all aspects, also here (Scandinavia).

1. I have myself been active in ordering refurbishing of special valves, but for hydroelctric and high pressure freshwater systems, with good results. refurbishing companies were either original factory or free specialist companies with long successful records.

Checklist in my first posting used.

2. Agree on technical aspects, where you sometimes have to go down to known positive contributing details to strength: spindle diameter, bearing constructional details, fitting details of closing elements to spindle etc.

3. Sometimes it is acceptable (not forbidden) to state: equal to (brand one, brand 2 (one or more brands)), and in additions weight references to long-time troublefree operational records.

Note: I have seen some 'hopeless' weighted comparisons where for instance deliverytime and/or price are given high score, where you know the good brands needs higher price and longer time. But this is another discussion.