Parts of properties of control valves should be tested before installation. From delivery to installation, control valves and their attachments pass through transportation, storage and other environments. Different environments make properties of control valves and attachments change. So, the test of control valves should be carried out before installation.
Instrumentations suffer from random vibration caused by transportation facilities during transportation and impacts during handling. Moreover, climatic conditions such as temperatures and humidity change during transportation. The properties of instrumentations also change.
The properties of instrumentations may change because of climatic, biological and chemical environments varying during storage.
Mechanical stress caused by carrying and assembling during installation changes properties of instrumentations. However, installation is quite short. Installation has less influence.
Environmental conditions for testing control valves before installation
Just like conditions for testing instrumentations, the followings are conditions for testing control valves before installation:
1. Temperature: 10~35℃;
2. Humidity: Air relative humidity is lower than 85% and corrosive gas does not exist;
3. Having good illumination, clean, quietness and adequate ray of light;
4. Valves cannot be tested under the situations having high vibration, large noise, moist, much dust and strong magnetic field interference.
5. Should have inspection equipments such as power source, air source and hydraulic pump, water delivery and water draining equipments.
Points for testing control valves before installation:
1. Static characteristic test;
2. Air impermeability test;
3. Sealing test. Stuffing box can be reinstalled when it is necessary;
4. Leakage test;
5. No load stroke time test;
6. Insulating property test;
7. Compression strength test.
Feb 12,2015
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