Flowmeter water flow switch controller plug-in flow liquid flow meter sensor

Shenzhen Volcker is mainly engaged in the design/installation and technical development services of instruments and meters in the fields of fluid measurement and process control. At present, the company's main products include flow switches, pressure switches, temperature switches, electromagnetic flow meters, vortex flow meters, turbine flow meters, ultrasonic flow meters, level flow meters, and other instruments. Application industries: petrochemical, natural gas, machinery, electricity, metallurgy, building materials, food and pharmaceutical manufacturing, agriculture, environmental protection, and other fields. Our company can customize instrument specifications according to the special requirements of users and on-site conditions, and provide installation and debugging services

Knowledge extension:

Common faults of electromagnetic flow meters

Some common faults in the use of electromagnetic flow meters are caused by damage to the components of the instrument itself, while others are caused by improper selection, installation, environmental conditions, fluid characteristics, and other factors, such as display fluctuations, decreased accuracy, and even instrument damage. It can generally be divided into two types: faults that occur during installation and debugging (during debugging) and faults that occur during normal operation (during runtime).

The expected fault during debugging usually occurs during the installation and debugging stage of the instrument. Once eliminated, it will not occur again under the same conditions in the future. Common debugging failures are usually caused by improper installation, environmental interference, and fluid characteristics.

Usually, the fault is caused by the incorrect installation position of the electromagnetic flow sensor, such as installing the sensor at a pipeline point that is prone to gas accumulation; Or installed on a vertical pipe from top to bottom, which may cause emptying; Or there is no back pressure behind the sensor, and the fluid is directly discharged into the atmosphere, resulting in a measurement tube that is not full.

Usually, it is mainly caused by stray current interference in pipelines, strong electromagnetic wave interference in space, and magnetic field interference in large motors. The interference of stray current in pipelines usually results in satisfactory results through good individual grounding protection. However, if strong stray current is encountered (such as in electrolysis workshop pipelines, sometimes the peak AC potential Vpp induced on the two electrodes can reach up to 1V), additional measures and insulation between flow sensors and pipelines need to be taken. Space electromagnetic wave interference is generally introduced through signal cables and is usually protected by single-layer or multi-layer shielding.

The presence of uniformly distributed small bubbles in the measured liquid usually does not affect the normal operation of the electromagnetic flow meter. However, as the bubbles increase, the output signal of the instrument will fluctuate. If the bubbles are large enough to cover the entire electrode surface, as the bubbles flow through the electrode, the electrode circuit will instantly open circuit, causing greater fluctuations in the output signal.

When an electromagnetic flowmeter excited by low-frequency square waves measures too much solid content in the slurry, it will also generate slurry noise, causing fluctuations in the output signal.

When measuring mixed media, if the flow sensor is used for measurement before the mixing is even, it will also cause fluctuations in the output signal.

Improper selection of electrode materials and the tested medium can also affect normal measurement due to chemical reactions or polarization phenomena. Electrode materials should be correctly selected according to instrument selection or relevant manuals.

Operation period faults refer to faults that occur after electromagnetic flow meters have been debugged and operated normally for a period of time. Common operation period faults are generally caused by factors such as the adhesion layer on the inner wall of the flow sensor, lightning strikes, and changes in environmental conditions.

1) Sensor inner wall attachment layer

Due to the fact that electromagnetic flow meters are often used to measure dirty fluids, after running for a period of time, adhesion layers often accumulate on the inner wall of the sensor, resulting in malfunctions. These faults are often caused by the conductivity of the attached layer being too high or too low. If the attachment is an insulation layer, there will be an open circuit in the electrode circuit and the instrument will not function properly; If the conductivity of the attachment layer is higher than that of the fluid, there will be a short circuit in the electrode circuit and the instrument will not function properly. Therefore, the attached scale layer inside the measuring tube of the electromagnetic flowmeter should be removed in a timely manner.

Lightning strikes can easily induce high voltage and surge current in the instrument circuit, causing damage to the instrument. It is mainly introduced through power lines, excitation coils, or flow signal lines between sensors and converters, especially from the control room power lines, which account for the majority.

During debugging, due to good environmental conditions (such as the absence of interference sources), the flow meter operates normally, and it is often easy to overlook installation conditions (such as poor grounding). In this case, once the environmental conditions change and new interference sources appear during operation (such as welding on pipelines near the flow meter, installing large transformers nearby, etc.), it will interfere with the normal operation of the instrument, and the output signal of the flow meter will fluctuate