Bellows Cycle Life & How Manufacturing Processes Can Impact it

Transcription

1 40 th Gas-Lift Workshop Houston, Texas, USA Oct , 2017 Bellows Cycle Life & How Manufacturing Processes Can Impact it Mark Davey / Principal Engineer 2017 Gas-Lift Workshop 1

2 Overview API 19G2 is demanding strict set of testing requirements for gas lift components. Gas lift valve manufacturers desire to fully understand the life of their products, and key to this is bellows life. Senior Flexonics has performed our own bellows component durability testing and discovered that the manufacturing process used to make the bellows can significantly affect bellows life Gas-Lift Workshop 2

3 Presentation Outline Durability testing & results of bellows components Manufacturing methods for bellows Effects of manufacturing method on bellows life Other considerations for bellows use in valves Suggestions for further study 2017 Gas-Lift Workshop 3

4 Overview Valve manufacturers wish to know what the bellows are capable of. All bellows are not alike. All bellows manufacturing processes are not alike Gas-Lift Workshop 4

5 Bellows Nomenclature Outward Formed (Hydroformed) Outward & Inward Formed (Mechanically Formed) 2017 Gas-Lift Workshop 5

6 Durability Testing Bellows Components Senior performed durability cycle testing on a batch of 7 of each of the following: Mechanically formed 1 bellows Hydroformed 1 bellows Testing was accelerated to 150% of rated stroke to quickly produce failure data Why? Extension or compression? Either was verified to be acceptable 2017 Gas-Lift Workshop 6

7 Durability Testing Bellows Components Testing Conditions: Not in a valve bellows only Constant stroke, constant 2hz rate mechanically guided axial actuation Internally pressurized to 50 psi for leakage (failure detection) No installation loads & stresses No hydrostatic aging tests No operating pressure cycles No elevated temperatures No exposure to corrosive chemicals These can degrade bellows life Gas-Lift Workshop 7

8 Accelerated Fatigue Test Test Setup Test Unit Programmable Hydraulic Actuator (1% Repeatability) Strong-back with pressure fe port Linear Guide Bearing 2017 Gas-Lift Workshop 8

9 Accelerated Fatigue Test Video 2017 Gas-Lift Workshop 9

10 Accelerated Fatigue Test Results Typical bellows fatigue failure (many cycles after initial leakage) Usually 1 st root on simple tests (especially hydroformed bellows) 2017 Gas-Lift Workshop 10

11 Accelerated Fatigue Test Results 2017 Gas-Lift Workshop 11

12 Accelerated Fatigue Test Results Reliability / Failure Probability Plots Hydroformed Avg. 28,672 Mechanically Formed Avg. 73,738 Over a 2.5 x Difference! 2017 Gas-Lift Workshop 12

13 Bellows Manufacturing Methods Outward Formed (Hydroformed) Outward & Inward Formed (Mechanically Formed) 13

14 Bellows Manufacturing Methods Method Pros Cons Outward Forming $ Manufacturing $$$Tools Inward & Outward Forming Cycle Life $ Manufacturing 2017 Gas-Lift Workshop 14

15 Bellows Manufacturing Methods FEA Forming Simulations - Strains Outward Forming ONLY NOTHING Inward & Outward Forming BOTH 2017 Gas-Lift Workshop 15

16 Bellows Hardness Readings from Forming NACE MR0175 LIMIT 35 HrC NO BENEFIT FROM STRAIN HARDENING 2017 Gas-Lift Workshop 16

17 Other Considerations for Bellows use in Valves Installation Loads & Stresses Don t crush bellows! Don t go past compression lockup! Rule of thumb: 30% change maximum from free length. Ageing: Don t shock it!!! Ramp up pressure SLOWLY! AP requires hydrostatic aging at 5,000 psi which can actually damage the bellows and reduce life. Bellows prefer external pressurization (eliminates squirm failure mode) 2017 Gas-Lift Workshop 17

18 Suggestions for Further Study Custom bellows for severe applications Higher pressure applications More extreme environments Refurbished components 2017 Gas-Lift Workshop 18

19 Summary Senior Flexonics bellows component durability testing reveals that the manufacturing process used to make the bellows can significantly affect bellows life as much as 2.5 : 1 Manufacturing induced strain hardening is beneficial for bellows fatigue life. Valve manufacturers can realize the best possible bellows life by avoiding damage during manufacturing & testing Gas-Lift Workshop 19

20 Questions? Bellows Cycle Life & How Manufacturing Processes Can Impact it 2017 Gas-Lift Workshop 20

21 Copyright Rights to this presentation are owned by the company(ies) and/or author(s) listed on the title page. By submitting this presentation to the Gas-Lift Workshop, they grant to the Workshop and the Artificial Lift Research and Development Council (ALRDC) rights to: Display the presentation at the Workshop. Place it on the web site, with access to the site to be as directed by the Workshop Steering Committee. Place it on a CD for distribution and/or sale as directed by the Workshop Steering Committee. Other uses of this presentation are prohibited without the expressed written permission of the company(ies) and/or author(s) who own it and the Workshop Steering Committee Gas-Lift Workshop 21

22 Disclaimer The following disclaimer shall be included as the last page of a Technical Presentation or Continuing Education Course. A similar disclaimer is included on the front page of the Gas-Lift Workshop Web Site. The Artificial Lift Research and Development Council and its officers and trustees, and the Gas-Lift Workshop Steering Committee members, and their supporting organizations and companies (here-inafter referred to as the Sponsoring Organizations), and the author(s) of this Technical Presentation or Continuing Education Training Course and their company(ies), provide this presentation and/or training material at the Gas-Lift Workshop "as is" without any warranty of any kind, express or implied, as to the accuracy of the information or the products or services referred to by any presenter (in so far as such warranties may be excluded under any relevant law) and these members and their companies will not be liable for unlawful actions and any losses or damage that may result from use of any presentation as a consequence of any inaccuracies in, or any omission from, the information which therein may be contained. The views, opinions, and conclusions expressed in these presentations and/or training materials are those of the author and not necessarily those of the Sponsoring Organizations. The author is solely responsible for the content of the materials. The Sponsoring Organizations cannot and do not warrant the accuracy of these documents beyond the source documents, although we do make every attempt to work from authoritative sources. The Sponsoring Organizations provide these presentations and/or training materials as a service. The Sponsoring Organizations make no representations or warranties, express or implied, with respect to the presentations and/or training materials, or any part thereof, including any warrantees of title, noninfringement of copyright or patent rights of others, merchantability, or fitness or suitability for any purpose Gas-Lift Workshop 22