High‑pressure industrial pipeline safety heavily relies on reliable trunnion ball valves. The 3‑piece trunnion mounted ball valve features split three‑body forged construction, fixed ball design and convenient on‑site maintenance. It is widely adopted in oil & gas, petrochemical, power plant and coal‑chemical severe‑service applicationsAlibaba.co....
Now we take you inside J‑VALVES modern valve workshop, to show the complete manufacturing workflow of API 6D certified 3‑piece trunnion ball valve, from raw forging blanks to final packed finished goods.
I. What is 3‑Piece Trunnion Mounted Ball Valve? Authoritative Standard Overview
A 3‑piece trunnion mounted ball valve consists of three separate body segments: left body, central body and right body, tightly bolted together. The ball is fixed by upper and lower trunnion shafts. Fluid pressure is borne by floating seats, which greatly reduces operating torque for large‑size & high‑pressure pipelines.
Our valves comply with globally‑recognized industrial standards:
1. Design & manufacturing: API 6D, ASME B16.34
2. Flange end: ASME B16.5
3. Fire‑safe & anti‑static: API 607
4. Test & inspection: API 598
Available body materials include WCB carbon steel, A105 forged steel, CF8M stainless steel. Pressure rating ranges from Class 150 up to Class 2500. Double Block & Bleed (DBB) function is available to meet strict oil‑gas safety specifications.
II. Factory Floor Tour: Complete Production Steps of 3‑Piece Trunnion Ball Valve
Step1: Raw Material Incoming Inspection
All forged blanks, ball components, seats and fasteners go through strict incoming checks. Spectro‑analysis verifies material chemical composition. Ultrasonic testing detects internal forging defects. Each batch keeps heat number traceability records. Defective raw materials are rejected before machining.
Step2: High‑Precision CNC Machining
Forged workpieces are processed on CNC machining centers. Flange faces, valve cavity bores, ball spherical surfaces and seat sealing faces are precisely machined. High spherical accuracy of ball component is critical for bubble‑tight zero‑leakage performance.
Step3：Component Cleaning & Seat Material Selection
Machined parts are cleaned to remove rust and oil residue. Sealing materials like RPTFE or hard‑faced metal seats are selected according to working media and temperature, for soft‑seat or metal‑seat options.
Step4：Workshop Assembly
Technicians assemble seats, fixed ball, stem and packing set strictly following assembly drawings. Heavy‑duty body bolts fasten three‑piece body segments. Gear operator is fitted afterwards. Operating torque is adjusted to guarantee smooth open‑close movement without jamming.
As you can see in our workshop photo, rows of assembled trunnion ball valves are ready for pressure testing.
Step5：API 598 Hydro‑static & Pneumatic Pressure Test
Every assembled valve undergoes mandatory tests: shell strength test, high‑pressure seal test and low‑pressure air seal test. Valves hold specified pressure for required duration. Zero shell leakage and zero seat leakage are compulsory for passing inspection. No defective valves move forward to next procedure.
Step6：Painting, Marking & Final Packing
Qualified valves are blast‑cleaned and coated with anti‑corrosion industrial paint. Permanent marking per MSS‑SP‑25 shows model, material, pressure class. Finished valves are well‑protected and packed in wooden crates for worldwide delivery, as shown in our factory real‑shot image.
III. Key Benefits & Typical Application of 3‑Piece Trunnion Mounted Ball Valve
1. Split three‑piece body: Internal components can be serviced without removing valve from pipeline, lowering maintenance cost.
2. Trunnion fixed ball design: Low operating torque under high pressure, suitable for gearbox, electric actuator automation.
3. Safety‑oriented construction: Anti‑static, fire‑safe design, DBB double block and bleed function for oil‑gas transmission safety requirements.
4. Wide material options: Carbon steel, stainless steel, special alloy grades for crude oil, natural gas, steam and corrosive chemical fluids.
Typical industries: oil‑gas gathering pipeline, refinery & chemical plant, power process piping, coal‑chemical industry, long‑distance transmission pipeline.
IV. Why Source 3‑Piece Trunnion Ball Valve from J‑VALVES Factory?
Founded in 2009, J‑VALVES delivers full‑range industrial valve solutions. We own complete in‑house forging, CNC machining, assembly and testing workshops. Both standard and custom‑built 3‑piece trunnion ball valves are available.
All products follow API international standards. Third‑party witness test is acceptable. We provide one‑stop service including valve selection, manufacturing and after‑sales support for global engineering clients.
Our real‑site workshop photo shows bulk completed 3PC trunnion ball valves. Every unit has passed full‑sequence inspection. Custom size, pressure class, material and actuator types are supported for your project.
V. Conclusion
A reliable 3‑piece trunnion mounted ball valve is more than simple part assembly. It depends on full‑system quality control: raw‑material NDT inspection, precision machining, standardized assembly and strict pressure validation. Visiting real valve factory helps you understand details behind API‑compliant industrial valves.
If you are searching for qualified manufacturer for 3‑piece trunnion ball valves, contact J‑VALVES for technical datasheets and competitive quotation.
