Refurbish ball valve for natural gas | Eng-Tips

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.

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 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.


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.

What is a Ball Valve?

A Ball Valveis a kind of valve that uses a round disc to manage fluid flow. The disc has a hole or opening in the middle. When this opening lines up with both ends of the valve, fluid flows through. When the valve shuts, the hole sits crosswise to the ends. Based on how they connect, Ball Valves split into types: flanged Ball Valve, fully welded Ball Valve, socket welded Ball Valve, and ring type jointed (RTJ) Ball Valve.

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What is a Gate Valve?

Gate Valves  are mainly built to start or stop flow. They aren’t meant for adjusting or slowing it. When the gate moves up from the flow path, fluid passes fully through. Gate Valves suit spots where you want straight flow and little blockage.

How Do Ball Valves and Gate Valves Differ in Design?

Internal Mechanism: Rotating Ball vs. Linear Gate

A Ball Valve has a spinning ball inside with a hole through it. Turning this ball decides if fluid goes through or stops. This setup makes it fast to use. It only needs a quarter-turn to open or close all the way.
Gate Valves use a straight-moving gate.

Sealing Mechanism: Tight Shutoff vs. Partial Flow Control

Ball Valves seal tightly , ideal for jobs needing a full stop with no leaks.
Gate Valves allow some flow control, making them better for unrestricted full flow with minimal pressure drop.

What Are the Operational Mechanics of Ball and Gate Valves?

Quarter-Turn Motion vs. Multi-Turn Rotation

Ball Valves use a quarter-turn move. This lets them open or close fast with little work. It’s handy for jobs needing quick shutoff.
Gate Valves need many turns to run. They take longer to open or close than Ball Valves. This slow pace can help in cases where you want gentle closing to avoid water hammer.

How Do Ball Valves and Gate Valves Perform in Different Applications?

Flow Control Efficiency: Full Bore vs. Throttling Capability

Ball Valves often have a full bore design. This means wide-open flow with no big pressure drops across systems. Gate Valves are strong at throttling. They can shift between fully open and closed better than Ball Valves. But this might cause bigger pressure drops when half-open.

Pressure Drop and Leakage Risks

Ball Valves usually have lower pressure drops. Their smooth design cuts resistance while working. They also seal great against leaks, even under high pressure.
Gate Valves might see higher pressure drops, especially when partly open. They aren’t made just for throttling. Still, they stay solid where small leaks are okay for the job.

Which Applications Suit Ball Valves or Gate Valves Best?

Ideal Use Cases for Ball Valves: High-Pressure, Fast Shutoff Systems

Ball Valves:Ideal for high-pressure systems requiring instant shutoff and perfect for emergencies or applications needing leak-proof sealing.

Gate Valves:Suits for thick fluids, slurries, or systems needing flow throttling.Gate Valves help in systems where slow flow control stops sudden pressure jumps.

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What Are the Maintenance and Durability Considerations?

Wear Resistance: Ball Valve Longevity vs. Gate Valve Seat Erosion

Ball Valves last long thanks to their simple setup and fewer moving bits. This means less wear over time and lower upkeep needs. Gate Valves, though, might face seat wear. The gate slides against the seat when moving. This can raise upkeep demands.

Repair Complexity: Modular vs. Disassembly-Intensive

Repair difficulty varies a lot. Ball Valves often have a modular build. You can swap parts without tearing much apart. This cuts downtime during fixes. Gate Valves might need more breakdown to reach inside pieces for repairs or swaps.

How Do Cost and Installation Factors Compare?

Initial Investment and Lifetime Cost Comparison

When looking at costs, Ball Valves often cost more upfront. Their sturdy build and tight seals drive the price up. But their long life and low upkeep can save money over time.

Gate Valves usually cost less to buy. Yet, they might rack up higher costs later. This comes from upkeep needs tied to seat wear or part breakdown.

Space Requirements and Installation Flexibility

Ball Valves are small in size. This lets them fit in tight spots easily. Their quarter-turn action also boosts setup options. They need less room to work than multi-turn Gate Valves.

Gate Valves may need more space to set up. Their straight-moving setup demands extra room around the valve body when running.

Why Choose FLUIDO for Customized Valve Solutions?

FLUIDO stands out for custom valve fixes made just for what customers need across different fields. FLUIDO makes sure each fix works best under specific conditions.

By picking materials—like stainless steel in their 2PC Stainless Steel Flanged Ball Valve—FLUIDO delivers trusty solutions. These meet tough quality rules while tackling unique job challenges well.

Want more information on Welded Ball Valve? Feel free to contact us.