Home › About
About Kevin Lyu — independent valve inspector in Ningbo
About 12 years of hands-on QC inside a Ningbo valve factory, now inspecting and witnessing tests for overseas buyers across Zhejiang.
Who inspects your valves
ValveWitness Inspection is run by Kevin Lyu (吕中国), a valve quality-control engineer based in Ningbo High-tech Zone, Zhejiang. Inspections are carried out by Kevin in person; he writes the English report and is accountable for every result in it.
He spent about 12 years (December 2013 – January 2026) as an in-house QC engineer at a valve manufacturer in Ningbo, after about 11 years of supplier quality management (2002–2013). Every decision is based on the drawing and on measured data, and every measurement is recorded so it can be traced.
- Name
- Kevin Lyu (吕中国)
- Role
- Independent valve & machinery inspector
- Base
- Ningbo High-tech Zone, Zhejiang, China
- Valve QC experience
- About 12 years in a valve factory (2013–2026)
- Before that
- About 11 years of supplier quality management (2002–2013)
- Languages
- Chinese (native); English for written reports and day-to-day communication
- Contact
- kevin@valvewitness.com
WhatsApp +86 131 2757 0627
Factory QC experience, in numbers
As QC engineer at a Ningbo valve manufacturer (2013–2026), Kevin:
- inspected 180+ batches of incoming material a year — castings, forgings, seals and other parts — against drawings and technical agreements, with a written record for every batch and no non-conforming material released;
- verified critical dimensions daily against process standards and ran shell strength and seat sealing tests on finished valves;
- carried out final checks at 3 core suppliers before shipment, cross-checking material certificates, full dimensional records and pressure test data, and signed 300+ release notes a year;
- ran two scheduled process patrols a day plus random sampling, logging and reporting about 60 process abnormalities a year;
- was stationed at key partner factories for several months at a time to supervise the full production process;
- supported customer-complaint investigations with fault reproduction, measurement and root-cause analysis.
Before that, in supplier quality management (2002–2013), he ran supplier qualification assessments, system audits and on-site audits, monitored suppliers’ processes and outgoing quality, and followed up corrective actions.
What he checks best
- Valve pressure testing — shell strength and seat sealing tests; familiar with API 598 and EN 12266 test requirements
- Dimensional inspection — critical dimensions against drawings with calipers and micrometers
- Document review — material certificates, dimensional reports and pressure test records
- Inspection stages — incoming, in-process (patrol), final and pre-shipment inspection; supplier audits
- Products — stainless steel ball valves, silent (noise-reduction) check valves and butterfly valves
An example from the test bench
On one silent check valve design, valves were tight on the water seat test at 18 bar (1.1× the standard pressure) but showed micro-leakage on the 6 bar air test. The investigation traced it to a design change: the shaft-to-bracket clearance had been reduced by 0.10 mm to make closing quieter, so the disc slightly interfered as it closed. High water pressure still pushed the disc onto the seat; low air pressure could not. Restoring the original clearance tolerance removed the leak. It is why we always ask which closure tests your PO requires — a valve can pass one and fail another.
How we stay independent
- We report facts from the samples inspected — PASS, FAIL or PENDING — with the original photos.
- The factory performs pressure tests on its own bench; we witness, time the holds and record the results.
- We do not accept gifts or “arrangements” from factories.
- We are not accredited (no ISO/IEC 17020) and do not issue certificates of conformity. Standards named on this site are public standards we work to, not certifications we hold.
Education
Bachelor’s degree, Shanghai University (Higher Education Self-study Examination).
Last updated: 2026-11-14