1. Product Introduction
LMU series ultrasonic level meter is a compact 2-wire integrated measuring device launched by Lanry Instruments. It consists of an integrated probe sensor and electronic processing unit with fully sealed leak-proof structure, enabling continuous non-contact level monitoring for liquids and solid materials. Suitable for harsh working conditions in metallurgy, chemical, electric power, petroleum and other industries, the product supports screw and flange mounting. Adopting the mature time-of-flight measurement principle, equipped with automatic temperature compensation and intelligent signal processing technology, it stably outputs standard 4-20mA analog signals, serving as a universal solution for tank and silo level monitoring.
The LMU series includes seven models categorized by maximum measuring range: LMU4, LMU6, LMU8, LMU12, LMU15, LMU20 and LMU30, with liquid measuring ranges covering 4m to 30m. For solid materials, ultrasonic waves are easily scattered and absorbed by powder, so the effective measuring range is only 50% of that in liquid working conditions. Model selection shall match on-site installation environment and material characteristics. The whole unit reaches IP67 protection grade; its metal outer cover features airtightness and alkali resistance, allowing stable long-term operation under -40℃~80℃ and ±0.1MPa normal pressure.
2. Core Measuring Principle
The device completes distance measurement via the time-of-flight acoustic method: the sensor emits ultrasonic pulses downward. After hitting the material surface, sound waves reflect back to the probe. The meter records the time interval t between transmission and reception, and calculates the distance D from the probe to material surface combined with sound velocity c, following the formula: D=c·t/2.
Operators input the total installation height H (empty tank distance) of the tank in advance, and the meter automatically converts real-time level L=H-D. A built-in integrated temperature sensor revises sound velocity deviation caused by temperature changes in real time to eliminate measuring errors from ambient temperature.
The instrument has a blanking distance (dead zone B), where echoes cannot be identified. The full scale F set during calibration must not extend into the blanking distance. The blanking distance of each model increases from 0.2m to 1.2m, and long-range models require larger reserved installation clearance. Only two sets of parameters (empty tank height and full scale) need to be input for quick calibration. Three induction buttons and a large 4-digit LCD display support convenient on-site debugging and reading.
3. Core Product Features
- Integrated compact design: The sensor and electronic unit are integrated as one piece, with screw/flange mounting options for easy disassembly and installation without separate wiring.
- Multi-circuit protection: Built-in overvoltage, overcurrent and lightning protection modules, adapting to complex power supply environments in factories.
- Excellent anti-interference capacity: Intelligent digital signal algorithm filters clutter generated by steam, dust, tank supports and agitators, fitting complex tank working conditions.
- Standard signal output: 4-20mA current output with 0~500Ω load capacity, directly connectable to PLC, recorders and other industrial control equipment; 4mA corresponds to empty tank while 20mA corresponds to full tank.
- Wide working condition adaptability: Metal electronic housing, ABS sensor probe, IP67 dustproof, waterproof and alkali-resistant performance, applicable to low/high temperature and slightly pressurized environments.
- Flexible beam angle: 8° (3dB) beam angle for 4/6/8m short-range models; 5° (3dB) beam angle for 12~30m long-range models, reducing echo interference from tank walls and boosting stability of long-distance measurement.
4. Application Scenarios
With the advantages of non-contact, wear-free performance and compatibility with both solids and liquids, LMU series is widely applied in monitoring various industrial storage facilities:
- Chemical industry: Level monitoring of acid-base storage tanks, sewage regulating tanks and reagent tanks;
- Power industry: Circulating water tanks, fly ash silos and desulfurization slurry tanks;
- Metallurgy industry: Cooling water pools, mineral silos and slag slurry tanks;
- Petroleum industry: Crude oil buffer tanks and oil separation sewage pools;
- General storage: Solid level measurement of grain silos, plastic particle bins and sand yards.
5. Summary
The LMU series integrated ultrasonic level transmitter is a 2-wire compact device for non-contact liquid and solid level measurement in chemical, power, metallurgical and petroleum industries. Adopting time-of-flight principle with temperature compensation, it features IP67 housing, lightning and overvoltage protection, 4-20mA output and 0.2%FS accuracy. Different beam angles suit various measuring ranges. Free from corrosion and material sticking, it offers low-maintenance monitoring for tanks, pools and silos under harsh working conditions.
Post time: Jul-29-2026