1. Description of the problem and scope of application
This manual is intended for diagnosing measurement errors in industrial flowmeters (electromagnetic, vortex, Coriolis). Problems considered: calibration drift, the effect of incorrect installation, changes in the physical properties of the medium (density, viscosity, presence of gas), as well as the formation of deposits on the sensors. Degree of criticality: from high (violation of the technological process, incorrect dosing of reagents) to low (minor deviation in reports).
2. Safety measures
ATTENTION: Before starting work on flowmeter diagnostics, it is necessary to perform the Lockout/Tagout (LOTO) procedure. Turn off the power to the appliance and lock the appropriate shut-off valves. Make sure there is no residual pressure in the pipeline. Use personal protective equipment (PPE), including safety glasses, gloves resistant to the working environment, and safety shoes. Working with measuring devices under pressure carries the risk of releasing hot or chemically aggressive substances.
3. Necessary diagnostic tools
| Tool | Specification | Measurement range | Purpose |
|---|
| Multimeter | Digital, True RMS | 0-1000V, 0-10A, 0-50 MΩ | Checking the power supply, 4-20 mA signals |
| Portable ultrasonic flowmeter | Invoice | according to the diameter of the pipe | Control measurement (reference) |
| Oscilloscope | Digital, 2 channels | DC - 50 MHz | Analysis of signal noise, checking pulses |
| Thermal imager | Industrial | -20...+500°C | Clogging diagnostics, local heating |
4. Initial assessment checklist
| Parameter | What to check/record |
|---|
| Working conditions | Current pressure and temperature compared to design |
| Physical changes | Have there been changes in the configuration of the pipeline or shut-off valves |
| Error history | Alarm log (error code, time of occurrence) |
| External condition | The presence of vibrations, corrosion, insulation damage |
5. Systematic diagnosis diagram
- Step 1: Checking the zero point.
- IF deviation at zero flow > 0.5% -> Check shut-off valves (tightness) or deposits.
- IF deviation = 0 -> Go to Step 2.
- Step 2: Signal stability analysis.
