Some performance tests shall be carried out before the installation of the control valve. From delivery to installation, the control valve and accessories are transported, stored and other environments. Different environmental conditions change the performance of the control valve and accessories. Therefore, pre installation inspection is required.
In addition, during transportation, the environmental temperature, humidity and other climatic conditions will change, so the performance of the instrument and equipment will change during transportation.
In the process of storage, instrument performance changes due to the change of climate, biological and chemical environment parameters of storage environment. Precautions
In the process of installation, the mechanical stress caused by handling or assembly also changes the performance of the instrument. However, the installation process is generally short, so the impact of the installation environment is small.
Environmental conditions for pre installation inspection of control valve
Similar to the environmental conditions of other instrument inspection, the environmental conditions of inspection site before installation of control valve are as follows.
a. Temperature: 10-35 ℃.
b. Humidity: the relative humidity of air shall not be greater than 85%. There is no corrosive gas.
d. Good working lighting, clean, quiet and full of light.
e. It shall not be inspected in places with large vibration, noise, humidity, dust and strong magnetic field interference.
f. There shall be power supply, air source, hydraulic pump and other inspection equipment, water supply and drainage equipment for inspection.
g. Power requirements: 50Hz, 220VAC or 48vdcil0%, 24vdci5%.
h. Air source requirements: clean, dry, dew point is 10 ℃ lower than the minimum ambient temperature, meeting the compressed air quality standard of the instrument,
The pressure is 0.5-0.7mpa, the pressure is stable, and the fluctuation is not more than ± 10% of the rated value. Precautions before installation of control valve
The inspection before installation of control valve mainly includes the following contents:
a. Static characteristic test of control valve;
b. Air tightness test;
c. If necessary, the stuffing box shall be reinstalled;
d. Leakage test;
e. No load full travel time test;
f. Insulation test;
g. Compressive strength test.
Before actual installation, the tests that must be carried out include appearance test, withstand voltage strength test, start and end error, dead zone, return difference, basic error test, leakage test, no-load full stroke time test, etc.