I. cleaning steps


The parts of the valve must be processed in the following process before assembly:


1. According to the processing requirements, some parts need to be polished, and the surface cannot have processing burr, etc.


2. Degrease all parts;


3. After degreasing, pickling and passivation shall be carried out, and the cleaning agent shall not contain phosphorus.


4. After pickling and passivation, clean it with pure water, without chemical residue. This step is omitted for carbon steel parts;


5. Dry the parts one by one with non-woven cloth, and do not leave the surface of parts such as wire wool, or dry them with clean nitrogen;


6. Wipe each part with non-woven cloth or precision filter paper stained with pure alcohol until there is no dirty color.


II. Assembly requirements


Cleaned parts must be sealed for installation. Requirements for installation process are as follows:


1. The installation workshop must be clean, or temporary clean areas shall be built, such as newly purchased color strip cloth or plastic film, to prevent dust from entering during installation.


2. Assembly workers must wear clean cotton work clothes, pure cotton hat, no hair leakage, clean shoes on feet, plastic gloves on hands, degreasing.


3. Tools for assembly must be degreased and cleaned before assembly to ensure cleanness.


III. other requirements


1. Purge the assembled valve with nitrogen for at least 1 minute.


2. The air tightness test must be conducted with pure nitrogen.


3. After the air tightness test is qualified, it shall be sealed with a clean polyethylene cap, which shall be soaked with organic solvent and wiped clean before use.


4. Then seal with vacuum bag.


5. Final packing.


6. Measures shall be taken during transportation to ensure that the package is not damaged.


IV. acceptance requirements


Acceptance shall be in accordance with Hg 20202-2000 code for construction and acceptance of degreasing engineering. Before assembly, each part shall be wiped with clean precision filter paper. Dead angle and constant color of filter paper shall be selected as qualified.