China Valves Manufacturer , Industrial Valves Supplier.




9:00-18:00 Mon-Fri GMT+8


Home » About Us » Manufacturing Process
Quality management system is ensure the establishment and effective implementation of the company to prevent defects,reduce variation and waste, continuous improvement of quality system. The spirit of quality first, leading technology, service efficiency, always are first of our quality policy. Continually meet and exceed customer’s expect and requirements for quality,delivery time and service.

Quality Assurance

 1 Purpose
To ensure the overall performance of products is in line with standard and to meet customer requirements.

 2 Scopes and Basis
Range: suitable for the final inspection and test of valves. Inspection is according to the order and customer requirements, standard specifications, design drawings requirements, memorandum of customer quality.

 3 Test procedure
3.1 For pressure test valve, the valve assembly after passing by the production department to inform the test personnel to conduct. Unqualified assembly valve refused to carry out a pressure test.
3.2 To sale the stock product for more than three months, need to do pressure test and final inspection test again.
3.3 valve pressure test pass, and after the paint finish and fitted with nameplates, inspectors are allowed to carry out the final inspection of finished products. Prior to the final inspection, product inspectors need to supervise the process of assembling ,the testing procedures, and the paint procedures, the product quality problems to be discovered sooner, the better.

 4 Sampling methods and Criteria
4.1 pressure test for 100% tests.
4.2 Final examiner weekly inspection of sample of not less than 5 units of pressure test qualified products by each pressure test personnel. If sampling is not eligible to warning the pressure test examiners more than punishment, and is not qualified for this batch, all tests carried out.
4.3 Whether stock or new assembly products, each specification of product ratio of ≥ 35% (must not be less than 5 units, less than 5 units for full test) with sections 5.2, 5.3 testing. If found to be unqualified, is ineligible to redouble their inspection; once again found to be unqualified, then the specifications for full inspection. For power station valve products, the dimensional inspection and visual inspection should be 100% proportions.
4.4 Delivery products must be tested with section 5.1~5.3 requires inspection, and are all qualified.

 5 Inspection requirements
Final inspection and testing including: product performance testing (pressure test), the finished product inspection and delivery inspection.
5.1 Performance testing (pressure test)
5.1.1 Accuracy of pressure gauges for pressure test at 1.5 level, pressure measurement range is between 25%~75% of pressure gauge measuring range.
5.1.2 Pressure test of valve is according to API 598, ISO5208, API 6D and the company's regulations of “valve pressure test specification”.
5.1.3 Pressure test results (including valve body, valve cover, wedge heat number) recorded in the table of "valve sealing performance test records".
5.1.4 Final inspection personnel supervise the test procedure and check the "valve sealing performance test records".
5.2 Dimensional inspections
5.2.1 For factory production of one-piece body (such as gate valves, check valves, globe valves), Since the process has been tested, flange dimensions and length of structure sampling ratio of ≥ 5% (must not be less than 2 sets, less than 2 sets for full test).
5.2.2 For factory production split valve body (Such as ball valve), the flange dimensional sampling proportional to 10% (not less than 3, less than 3 sets for full test), length of structure sampling ratio of ≥ 35% (must not be less than 5 units, less than 5 units for full test). Test of flange holes need to check whether key hole is correct.
5.2.3 For outsourcing valve or valve body, flange dimensions and length of structure sampling ratio of ≥ 35% (must not be less than 5 units, less than 5 units for full test).
5.3 Final inspection
5.3.1 Finished product testing before storage as follows:
A. Handwheel nut is tight: testing handwheel and handwheel nut tight (including certain required nut clamping handle valve);
B. Packing number: visual inspection for the depth of packing gland in stuffing box , the depth should be the about the one-third of the packing gland height and the same type of valves should keep the same. 
C. Gland flange hole clearance: Visual inspection hole in the gland flange and clearance around valve shaft should be uniform and not significantly different;
D. Drive device: inspection the drive device with opening indicates, its opening instructions are accurate and in place, drive connections to the valve is correct;
E. Nameplate: tests nameplate installed is correctly positioned or not, content and physical compatibility; stock temporarily no nailed nameplates;
F. Free pressure test water: Visual inspection within the valve body, body cavities without the remnants of test medium (water) and impurities;
G. External painting: Verify that the valve external paint according to the regulations, color, brightness, whether it meets the requirements. The storage of products, carbon steel coated with antirust paint stainless steel valves are typically not painted;
H. Cavity injection: testing whether carbon steel within the valve body cavity are sprayed (coated) anti-rust oil, stainless steel valve cavity does not spray oil;
I. Protective cover: testing the sealing surface of valve body flange with protection cover on both ends are exhaustive and well plugging;
J Complete Annex: check installation or ship separately parts (such as handles, handwheel, nut, etc) after certain spray (paint) with complete eligibility.
5.3.2 Press 5.3. Article 1 a to j, inspection, upon final inspection, final inspection personnel signed release on “orders"; nonconforming product must first isolate the store and rework at the scene in time to take measures to achieve qualified.
5.3.3 As provided by the rework number still does not meet the eligibility requirements, you must fill in the "unqualified review report", and based on program analysis, treatment, and take preventive and corrective measures.
5.4 Product delivery inspection
5.4.1 Product delivery, product inspector should be in line with "storage list" and checking one by one in kind, warehouse keeper should also carefully check.
5.4.2 Stock delivery, pay attention to inventory time, if inventory for more than three months, need to test again, after passing then can deliver.
5.4.3 Visual Test the spray (paint) paint quality, leak-free spray evenly.
5.4.4 Matching nameplates and physical compatibility.
5.4.5 Inspection outside parts have exhaustive, random parts inventory (refer to some parts do not fit on top of the product but separate packaging shipped, such as certain types of ball valve handles, and so on).

 6 Identify
6.1 Pressure test identifies
6.1.1 Pressure test and inspection of products, pressure test valve products within the product area.
6.1.2 pressure test failed required repair or rework the products, paints or chalks in valves for pressure test examiner identifies entity is as follows:
A. strength test failure needs welding, needs welding and painting the Red "-";
B. seal test failed the sealing surface of the corresponding draw yellow lines on the outer surfaces of the valve body.
6.1.3 Test of strength is not qualified and cannot be welded with a red "x" identifies the entity and discard (return).
6.1.4 After pressure testing, qualified product, unqualified product, waste products are required to be stored in the specified area.

 7 Records
7.1 After pressure test, completed by the test examiner "valve sealing performance test records".
7.2 Finished inspectors fill in "product test report", following the final inspection and signature release on the "delivery order".
7.3 Stock for more than three months to test again, and fill in the "valve sealing performance test records" ultimate test after passing the valve by pressure test inspectors putting product into the qualified product area.
7.4 Delivery of the product with "storage list" as credentials.
7.5 The workload review of pressure test inspectors is based on "valve sealing performance test records" .The work quality is based on the inspection results of product testing and customer complaints. Workload evaluation of product test inspectors is based on "product test reports" and "unqualified review report" (daily inspection report *), The work quality is based on appraisal of supervisors with inspection results and customer complaints. For there is no record which lead to quality problems and quality dispute, the recorded people take full responsibility.
7.6 The record should be handed over to clerical collate archive next day, if reason can be extended, but after the order is completed, all records should be finished archive. If you have any questions needed to find records, refer to the warranty Department clerk.
7.7 Records shall be kept for at least 10 years.

Subscribe for Newsletter

Subscribe to our email list and stay upto date with all our latest updates.
Copyright © 2018.Ningde Hangna Industrial Co.,Ltd. All Rights  Reserved. 
Supported by Leadong   Sitemap