1、 Cleaning steps

The components of the valve must undergo the following processes before assembly:

1. According to processing requirements, some parts need to be polished, and the surface must be free of machining burrs, etc;

2. All parts shall be degreased;

3. After degreasing, conduct acid pickling and passivation, and the cleaning agent does not contain phosphorus;

4. After pickling and passivation, rinse with pure water to ensure that there is no residue of chemicals. This step is omitted for carbon steel parts;

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

6. Wipe the parts one by one with a non-woven cloth or precision filter paper dipped in analytical pure alcohol until there is no dirty color.

2、 Assembly requirements

Cleaned components must be sealed and stored for installation. The requirements for the installation process are as follows:

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

2. Assembly workers must wear clean cotton work clothes, wear a pure cotton hat, prevent hair leakage, wear clean shoes on their feet, wear plastic gloves on their hands, and degrease.

3. Assembly tools must be degreased and cleaned before assembly to ensure cleanliness

3、 Other requirements

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

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

3. After passing the airtightness test, wrap it and seal it with a clean polyethylene cap. Before using the polyethylene cap, soak it in an organic solvent and wipe it clean.

4. Then seal with a vacuum bag.

5. Final packing.

6. During transportation, measures shall be taken to ensure that the package is not damaged.

4、 Acceptance requirements

Acceptance shall comply with HG 20202-2000 "Code for Construction and Acceptance of Degreasing Engineering". Before assembly, each component shall be wiped with clean precision filter paper, and the dead corner of the component shall be selected, and the filter paper shall not change its color as qualified.