Advantages and disadvantages of various common level measurement instruments

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Instrument Name, Measurement Principle, Advantages, Disadvantages: 1. Servo-level gauge – A motor drives a sensor that measures the buoyancy force acting on the float in order to determine changes in liquid level. It can measure interfaces and liquid levels. High precision. When the liquid in the tank fluctuates greatly or is viscous, it is common for the thin filaments to break, resulting in the loss of the float. 2. Radar level gauge: Principle of radar electromagnetic wave ranging. Do not come into contact with liquids. It can measure high-viscosity liquids and muds. The gas above the liquid surface absorbs electromagnetic waves, resulting in a phenomenon of wave loss. 3. Steel strip level gauge – buoyancy principle. As the liquid level changes, the floating disk moves up and down, and a steel belt is used to drive the long and short pointers outside the tank to rotate on the dial, thereby indicating the liquid level. More accurate. High precision is required for installation. In situations with frequent surface fluctuations, the ear holes of the floating pad are often worn through and damaged by the guide steel ropes. 4. Differential pressure level gauge, intelligent type – measures the difference in pressure between the bottom of the liquid and the gas above it, thereby determining the liquid level. It is widely used; gas-phase capillaries are prone to clogging, so it is necessary to determine the exact density of the liquid at appropriate times. 5. Capacitive level gauge: A metal rod is inserted into the container; the metal rod serves as one pole of the capacitor, while the container wall acts as the other pole. The change in capacitance is measured to determine the level of the liquid surface. Measurable solid particles, powdered particles. Calibration requires emptying and filling it, and the process is complex ； The measurement of the liquid dielectric constant has a significant impact. 6. Magnetostrictive level gauge: A pulsed current is generated in the sensor’s waveguide wire, creating a magnetic field around it. A permanent magnet float is attached to the outside of the sensor rod and can move up and down along this rod as the liquid level changes ； When the pulsed current magnetic field meets the float magnetic field, a torsional wave pulse is generated, which travels back to the detection mechanism along the waveguide wire at a constant speed. The position of the float can be determined accurately by measuring the time difference between the pulsed current and the torsional wave. High precision: The magnetic float is mounted on a guide tube and is used for measuring viscous or crystalline liquids; scaling on the magnetic float has occurred, causing it to get stuck ； When measuring large-volume containers, the guided wave wire is prone to drifting and breaking, making maintenance complex. 5. ELL external-mounted level gauge: sonar echo ranging principle, micro-vibration analysis technology. Fully contactless measurement. Suitable for the most demanding environments; safe, environmentally friendly, convenient and cost-effective, durable and reliable, as well as precise. It can measure media with high pressure, high temperature, strong corrosivity, high toxicity, high purity, and no contaminants. Medium viscosity