Daily and regular maintenance
1. Tour inspection
Check the instrument indicating the situation, whether there is any abnormality, see if he is fluctuating within the specified range; some transmitters do not have on-site instructions, go to the control room to see its secondary indication. Whether there is any debris around the instrument or whether there is dust on the surface of the instrument should be removed and cleaned in time. There are cases of accidental leakage and corrosion between the instrument and process interface, the pressure guiding tube and each valve.
2. Regular inspection
For some instruments that do not need to be inspected daily, it is necessary to check regularly. Regular zero checks, because the transmitter has a secondary valve or three valve group, five valve group, so zero checks is very convenient, does not require too much time. However, the transmitter used in the control system, regardless of the inspection time, still needs to change the automatic to manual control, so the zero return period of this instrument can be longer. Since these inspections require the removal of street inspection equipment, it is cumbersome, so if there is no abnormality, the inspection period can be longer.
Sewage, condensate, and venting are carried out on a regular basis.
Regularly purge the pressure pipe of the easily blocked medium, and fill the isolation liquid.
Regularly check the transmitter parts intact, no serious corrosion, damage; nameplate, logo clear and correct; fasteners should not be loose, the connector is in good contact, the terminal wiring is firm.
Regular on-site measurement of the line, including whether the input and output circuits are intact, whether the line is disconnected, short-circuited, and whether the insulation is reliable.
The housing must be well grounded while the transmitter is running. The transmitter used to protect the system should have measures to prevent power failure, short circuit, or open circuit.
In the winter season, the instrument should be inspected for the source and pipeline insulation and heat tracing to avoid damage to the source pipeline or the measuring components of the transmitter.
(1) Prevent the transmitter from coming into contact with corrosive or overheated media;
(2) preventing the deposition of dross in the conduit;
(3) When measuring the liquid pressure, the pressure tap should be opened on the side of the process pipe to avoid sedimentation;
(4) When measuring the gas pressure, the pressure tap should be opened at the top of the process pipe, and the transmitter should also be installed in the upper part of the process pipe so that the accumulated liquid can be easily injected into the process pipe;
(5) The pressure guiding pipe should be installed in a place with small temperature fluctuations;
(6) When measuring steam or other high-temperature media, it is necessary to add a condenser such as a buffer tube (coil), and the operating temperature of the transmitter should not exceed the limit;
(7) When freezing occurs in winter, the transmitter installed outside must adopt anti-freezing measures to prevent the liquid in the pressure inlet from expanding due to the volume of ice, resulting in damage;
(8) When measuring the liquid pressure, the installation position of the transmitter should avoid the impact of the liquid (water hammer phenomenon), so as to avoid the sensor over-voltage damage;
(9) When wiring, pass the cable through the waterproof connector (accessory) or the winding tube and tighten the sealing nut to prevent rainwater and the like from leaking into the transmitter housing through the cable.