Practical operation standards for environmental adaptation

Environmental adaptation should revolve around core factors such as temperature, vibration, and corrosiveness, while also providing protection for special scenarios. Specific requirements are as follows:

1. Temperature environment adaptation

Under normal operating conditions, it is necessary to control the installation environment temperature between 40-85 ℃ and avoid high-temperature equipment radiation areas. If it is unavoidable, insulation panels or ventilation devices need to be installed. For high-temperature media (temperature>80 ℃), it is necessary to install a condenser or U-shaped thermal buffer bend between the transmitter and the pipeline to prevent damage to the sensor diaphragm caused by high temperature.

When operating in low temperature environments (<5 ℃), anti freezing treatment should be applied to the pressure conduit and transmitter body. An electric heat tracing strip should be used with a 50mm thick rock wool insulation layer. If ethylene glycol solution is used for heat tracing, the pipeline temperature should be maintained at 1015 ℃ to avoid medium freezing and blockage.

2. Vibration and electromagnetic interference prevention and control

Priority should be given to installing in areas with low vibration. If installed near vibration sources such as pump bodies or compressors, stable brackets such as SUS304 L-shaped brackets should be used for fixation. Shock absorbers should be added to the connection between the bracket and the transmitter, and the vibration acceleration should be controlled within the rated range of the equipment.

Stay away from strong electromagnetic interference sources such as frequency converters and high-voltage lines. Shielded cables should be used for electrical wiring, and only one end of the control room should be grounded to avoid signal interference caused by multiple grounding points, ensuring stable transmission of 420mA signals.

3. Special environmental protection

In corrosive environments, corrosion-resistant transmitters such as Hastelloy and Tantalum materials should be selected, and the wiring ports should be sealed to prevent corrosive gases or liquids from entering the housing and wiring terminals; If the environment is highly corrosive, a sealed protective box can be installed and regularly ventilated.

Before installing in explosion-proof scenarios, it is necessary to confirm that the equipment's ATEX, IECEx, and other explosion-proof certifications match the on-site level. When wiring, the power must be turned off, and it is forbidden to open the cover with electricity. After wiring, tighten the explosion-proof waterproof joint.

Key points for practical operation of pipeline connection

The pipeline connection requires key steps such as matching the control interface, installing the pressure pipe, and coordinating the valve group. Different media also need to be adjusted accordingly, as follows:

1. Basic connection specifications

In terms of interface matching, first confirm the transmitter interface type. The Rc1/4 and Rc1/2 internal thread joints should be sealed with PTFE sealing tape, and the flange interface should use graphite or PTFE special gaskets. The use of sealant is strictly prohibited. If the interface size does not match the pressure pipe, a transition joint compatible with the same medium is required. For corrosive media, Hastelloy alloy material joints are preferred. Before connection, the interface dust plug needs to be removed, and the exposure time after removal should not exceed 15 minutes to prevent foreign objects from entering the measurement room.

The high and low pressure ends cannot be reversed. The "H" end marked on the transmitter body is connected to the high pressure side of the measured medium, and the "L" end is connected to the low pressure side. When measuring differential pressure, the high pressure end corresponds to the upstream pressure port, and the low pressure end corresponds to the downstream pressure port, to avoid reverse connection and damage to the sensor.

2. Fine installation of pressure pipes

The material and slope should be adapted according to the needs. Seamless steel pipes are used for ordinary media, and polytetrafluoroethylene pipes are used for strong corrosive media; The minimum inclination of the pressure pipe is 1:12, and for viscous or easily crystallized media, it needs to be increased to 1:6, while adding a heat tracing device. The length of the pressure pipes on both sides should be as consistent as possible, and the temperature difference should be controlled within 2 ℃. If necessary, an insulation layer should be added.

There are differences in the installation of pressure pipes for different media: the centerline of the pressure inlet for liquid media has an angle of ≥ 15 ° with the horizontal plane, and the pressure pipe tilts upwards towards the transmitter for easy exhaust; The pressure inlet of the gas medium is vertically upward or at an angle of ≥ 15 °, and the pressure pipe is inclined downward towards the transmitter, which is conducive to liquid discharge; The steam medium needs to be installed in a symmetrical condenser tank, with a 1:10 slope maintained in the horizontal section of the pressure pipe, and a height difference of ≤ 10mm in the condenser tank, filled with deionized water of the same temperature.

3. Installation of valve group and additional devices

The installation of the three valve group should ensure alignment with the transmitter axis to avoid mechanical stress. The operation sequence is: first close the balance valve, then open the high and low pressure valve, and finally adjust the balance valve; Before stopping, open the balance valve first, and then close the high and low pressure valves in sequence.

Install a filter at the inlet of the pressure pipe for media containing particles; Easy to crystallize and viscous media require a flushing ring and a double flange differential pressure transmitter, with the length of the pressure pipe controlled within 1.5m. After installation, an air tightness test is required, using 1.25 times the working pressure for helium leak detection to ensure a leakage rate of ≤ 1 × 10 ^ 6 cubic meters/s.

4. Key points for coordination with throttling devices

If equipped with orifice plates, Venturi tubes, and other throttling devices, it is necessary to ensure that the flow direction arrow of the throttling device is consistent with the flow direction of the medium, and the straight pipe section meets the requirements of front to back 5D (D is the pipe diameter). When installing orifice plates on horizontal pipelines, the orifice plates should be located within a range of 15 ° 45 ° above the centerline of the pipeline; When installing vertical pipelines, the deviation between the centerline of the orifice plate opening and the pipeline axis should be ≤ 1 ° to avoid the influence of medium eddy currents on measurement accuracy.