Precautions for Installation of Electromagnetic Flowmeters

1. Straight Pipe Section Requirements (Critical for Measuring Accuracy)

1. The upstream straight pipe length shall be no less than 5DN, and the downstream straight pipe no less than 2DN.
2. If elbows, valves, pumps or tees are installed upstream of the meter, extend the upstream straight pipe to 10DN.
3. Install regulating valves downstream of the flowmeter to avoid flow field disturbance caused by throttling.

2. Installation Position & Air Venting Rules

1. Horizontal installation is preferred, with electrodes kept horizontal to prevent air bubbles from adhering to electrodes.
2. For vertical installation, fluid must flow upward from bottom to top. Downward flow is forbidden to avoid air accumulation inside the tube.
3. Do not mount the flow sensor at the lowest point of the pipeline; residual corrosive liquid will soak the lining and electrodes after shutdown.
4. Install air vent valves at high points of pipelines and upstream of the meter. Entrained bubbles will lead to signal fluctuation and inaccurate measurement.

3. Grounding Specifications (Essential for Corrosive & Conductive Media)

1. For sewage, brine, acid and alkali liquids, install anti-corrosion grounding rings on both flanges of the sensor.
2. The flowmeter requires an independent grounding electrode. Sharing grounding with water pumps, motors and valves is prohibited.
3. If the pipeline is made of non-metallic materials such as plastic or FRP, grounding rings are mandatory. For metal pipelines, reliable conductive connection to ground is acceptable.
4. Stray currents will cause electrochemical corrosion of electrodes and zero drift. Strict grounding is required for corrosive working conditions.

4. Installation Difference Between Integrated & Split Types

1. Select split type for high-temperature media, buried pipelines and workshops with acid mist or salt fog. Mount the converter in well-ventilated, corrosion-free and room-temperature control cabinets.
2. Use dedicated shielded signal cables to connect the sensor and converter. All cable joints shall be fully sealed to prevent corrosive gas from invading circuit boards.
3. Integrated flowmeters can be adopted for indoor pipelines with normal temperature and clean, non-corrosive surroundings for easier wiring and installation.

5. Special Fitting Requirements for Corrosive Environments

1. Ordinary rubber gaskets are not allowed for flanges. PTFE wrapped gaskets shall be used for strong acid, strong alkali and brine to avoid leakage caused by gasket swelling and aging.
2. Coat the outer surface of the sensor body with anti-corrosion paint. Set drainage ditches around trenches for buried pipelines to eliminate accumulated water.
3. Reserve sufficient maintenance clearance around the sensor. Do not seal the meter in narrow airless pits for regular inspection of lining and electrode corrosion.

6. Matching Medium & Working Conditions

1. The conductivity of measured liquid must meet the minimum requirement of the meter. Pure water, oil and gas cannot be measured.
2. PU lining for highly abrasive slurry and sludge; PTFE lining for strong acid and alkali; rubber lining for neutral sewage. Optional electrodes include 316L stainless steel, titanium, tantalum and Hastelloy alloy as per actual media.
3. Avoid long-term empty-tube operation, which will cause irregular jumping flow readings.

7. Wiring, Protection & Ambient Conditions

1. Keep signal cables away from power cables and frequency converters to avoid electromagnetic interference.
2. Adopt converters with IP67 / IP68 stainless steel housings for outdoor and coastal salt fog environments.
3. Use explosion-proof flowmeters in hazardous areas, and conduct wiring and sealing in full compliance with explosion-proof standards.

8. Maintenance Reserve Design