Factory & Quality

Factory tour

Photographs from our plant and from one recent order going through inspection. Every image on this page was taken on site. Stages we have not yet photographed are not shown; they are described on the manufacturing page.

Company: DERVOS VALVE CO., LTD
Plant address: No. 105, Dayuan Street, Nanmingshan Subdistrict, Liandu District, Lishui City, Zhejiang Province, China

Entrance to the DERVOS VALVE CO., LTD plant, with the company name on the gate sign — 1. The plant. Entrance, with the company name on the gate sign.

Assembly and paint shops

Bodies in the shop are marked with size, class and material grade. The same marking is read at inspection and again against the certificate package.

Cast Y-pattern valve body marked 8, 2500 and WCB in the assembly shop — 2. Assembly shop. Y-pattern body cast 8 / 2500 / WCB.

Pressure seal check valves and Y-pattern bodies hanging on the paint line — 3. Paint shop. Pressure seal check valves and Y-pattern bodies on the paint line.

One order, through inspection

An NPS 10 Class 2500 check valve in WCC, heat number K5777. From order drawing to final coating check. The heat number on the body is the one on its certificate, so this item can be traced from these photographs to its document package.

Approved general arrangement drawing of a Class 2500 check valve with parts list — 4. Order drawing. The GA drawing is approved by the buyer before manufacture starts.

Face-to-face dimension of the assembled check valve measured with a large caliper bar — 5. Dimensional check after assembly, face-to-face against the approved drawing.

NPS 10 Class 2500 WCC check valve in the hydrostatic test rig, body marked 10, 2500, WCC and heat number K5777 — 6. Pressure test 1. Body marked 10 / 2500 / WCC, heat K5777, clamped in the test rig.

Test gauge graduated 0 to 100 MPa with its calibration label attached — 7. Pressure test 2. The test gauge, with its calibration label on the dial.

Dry film thickness gauge being used on the painted valve body — 8. Paint thickness test. Dry film thickness measured on the finished body.

Between these photographs

What happens at each stage, and the record it leaves behind.

Manufacturing
The full route, stage by stage, and the record each stage produces
Material traceability
How a heat number is followed from mill certificate to nameplate
NDE inspection
RT, UT, MT and PT: what each finds and what the report should show
Pressure testing
Test pressures, durations and what makes a test report credible
Inspection workflow (ITP)
Hold points and witness points, and who signs each
Packaging and shipping
End protection, crating and shipping marks

Visit or witness an inspection

Tell us the items you want to see and the dates that suit you or your third-party inspector, and we will confirm which hold and witness points fall in that window.