What are the advantages and disadvantages of the different types of manhole level gauges?

　　 Manhole level gauge What are the advantages and disadvantages?

　　A level gauge is a type of instrument used to measure the liquid level. The height of the liquid medium in a container is referred to as the liquid level. Common types include tuning-fork vibration, magnetic levitation, pressure‑type, ultrasonic, sonar‑wave, magnetic flap, and radar gauges. So, what are the advantages and disadvantages of each type of manhole level gauge?

　　What are the advantages and disadvantages of the different types of manhole level gauges?

　　1. Differential-pressure level transmitter: The operating principle of a double-flange (or single-flange) differential-pressure transmitter is that, as the liquid level in the tank changes, the hydrostatic pressure generated by the liquid level also varies accordingly.

　　(1) Advantages: excellent stability, high cost-effectiveness, and unaffected by internal conditions of the tank.

　　(2) Disadvantages: Requires contact with the measured medium, is significantly affected by density, and exhibits hysteresis when the capillary tube is excessively long.

　　2. Radar Level Transmitters: Radar level transmitters are categorized into non-contact radar and guided-wave radar types. The principle is that the transmitter emits high-frequency electromagnetic pulses toward the liquid surface (in guided-wave radar, the pulses travel along a cable or probe), and then measures the time difference between the transmitted pulse and the reflected echo to calculate the liquid level height.

　　(1) Advantages: Unaffected by temperature, steam, dust, foam, and other factors.

　　(2) Drawbacks: Requires direct contact with the medium and has specific requirements for the dielectric constant; cable and probe rods are prone to material buildup, and the cable may become detached.

　　3. Magnetostrictive and Float Level Gauges: The principle of the magnetostrictive level gauge is that the transmitter emits a low‑current pulse signal, which travels downward along the magnetostrictive waveguide, generating an annular magnetic field. When this magnetic field encounters the float, a torsional stress pulse is generated at the interface between the float’s internal magnetic field and the external field; this pulse is detected by the instrument, and the liquid level height is calculated from the time difference between the pulse transmission and reception.

　　(1) Advantages: High accuracy; suitable for short spacing.

　　(2) Disadvantages: Contact with the process medium; unsuitable for certain media; the float can easily become jammed; not applicable to low‑density fluids; high maintenance costs.

　　What are the characteristics of a manhole level gauge?

　　1. The integrated level gauge features a unique design and is easy to install.

　　2. Three-wire connection, with strong ultrasonic wave emission.

　　3. The well-level gauge features a low blind zone and high sensitivity.

　　4. Intelligent signal processing technology, adaptable to various operating conditions.

　　5. The level gauge features unique automatic power control and automatic gain control.

　　6. Overvoltage and overcurrent protection, lightning protection.

　　7. Opto-isolated 4–20 mA current output.

　　8. Fail-safe: the current output is 22 mA.

　　9. The dual-relay level transmitter for manholes can handle high currents and is used for pump control or alarm signaling.

　　10. Large LCD or LED display window for easy debugging and monitoring.

　　11. Advanced self‑clamping terminals ensure secure, vibration‑free wiring.

　　12. Adjustable sound speed for more accurate measurements.

　　13. All-plastic housing (IP68), acid- and alkali-resistant, suitable for harsh environments.

　　14. Installation of the flexible support or flange for the manhole level gauge.

　　15. Manhole level gauge Optional power supply options: DC 24 V or AC 220 V.