Magnetic Flip Plate Level Gauge Application Scenario

Special media adaptability

High viscosity liquids (such as asphalt, resin): the use of enlarged float + low friction guide rod to reduce viscous resistance.

Corrosive media (such as hydrochloric acid, liquid chlorine): float material selection of Hastelloy C276 or titanium, the main pipe lined with PTFE.

Low-temperature media (such as LNG, liquid oxygen): low-temperature special float (aluminum alloy) + vacuum jacket insulation structure.

Easy to crystallize liquids (such as caustic soda): steam accompanied by heat or double-chamber isolation design to prevent crystallization clogging.

Interface Measurement Application

Principle: Utilizing the density difference between two liquids (Δρ≥0.1g/cm3), the interface position is distinguished by a double float system (top float density ρ?<ρ?<bottom float density).

Example: Oil-water interface monitoring in a crude oil dewatering tank with float densities set to 0.8g/cm3 (oil) and 1.1g/cm3 (water).

Theoretical analysis:

1. Buoyancy balance equation: The buoyant force on the float satisfies: \( F_{buoyancy} = \rho_{liquid} \cdot g \cdot V_{displaced} = F_{gravity} = m_{floater} \cdot g \).

- Critical density: For normal operation of the float, the medium density \( \rho \) must be ≥ the average density of the float \( \rho_e \) (typical values range from 0.45 to 1.5 g/cm3, adjustable).

- Sensitivity analysis: The larger the volume \( V \) of the float, the more sensitive it is to changes in density, but it is limited by installation space.

2. Magnetic coupling transmission model:

- Magnetic field strength requirement: The surface magnetic field of the float's permanent magnet must be ≥ 800 Gauss to ensure it can drive the external flip board (spacing ≤ 10 mm).

- Hysteresis effect: There is a dead zone of ±2 to 5 mm when the flip board flips, which can be reduced through magnetic enhancement design (e.g., using neodymium iron boron rings).

3. Sources of Error and Compensation

Type of Error Cause of Error Compensation Method

Temperature Error Medium Density Variation with Temperature Built-in Temperature Sensor + Density Compensation Algorithm (Remote Transmission)

Pressure Error High Pressure Leads to Float Cavity Deformation Thick Walled Tube Design (Sch.80 and Above)

Mounting Errors Non-Vertical Installation (Inclined >2°) Laser Calibration + Level Adjustment

4. Dynamic Response Characteristics

Response Time: Typically <1 second, but may extend to several seconds for high viscosity media.

Fluctuation suppression: Reduction of the effects of liquid level fluctuations by means of damping chambers or floating stabilizers.

Technical Evolution Directions: 1. Smart Upgrade - Integration of HART/Profibus-PA protocols for digital calibration and diagnostics. - Equipped with self-diagnostic functions such as float jam alarm and magnetic field attenuation detection. 2. Material Innovation - Composite ceramic float: superior corrosion resistance suitable for extreme media like hydrofluoric acid. - Superhydrophobic coating: reduces adhesion of viscous media. 3. Structural Optimization - Modular design

Comparison of Other Level Measurement Technologies

Technical Parameters

Magnetic Float Level Gauge

Radar Level Gauge

Capacitive Level Sensor

Measurement Principle

Buoyancy + Magnetic Coupling

Microwave Reflection

Dielectric Constant Change

Applicable Medium

Liquid/Interface

Liquid/Solid

Conductive/Non-conductive Liquid

Accuracy

±5mm

±1mm

±0.5%FS

Pressure Resistance Capability

≤42MPa

≤10MPa

≤6MPa

Maintenance Cost

Low (No Moving Parts)

Medium (Regular Antenna Cleaning)

High (Prone to Coating Influence)