An ultrasonic level gauge is a microprocessor-based digital level meter. Its transducer sends ultrasonic pulses during measurement; the waves reflect off the material surface and are picked up by the original sensor or a matched receiver. Piezoelectric crystals or magnetostrictive elements turn the ultrasonic pulses into electric signals. The instrument computes the sensor-to-surface distance using the sound wave’s transmit-receive time difference. Thanks to its non-contact measuring mode, it has few restrictions on measured media and is widely used to detect the level of different liquids and solid substances.
FEATURES
| 🟩 It employs an advanced microprocessor; | 🟩 Built-in temperature compensation; | ||
| 🟩 Unique echo processing technology; | 🟩 Small beam; | ||
| 🟩 False echo storage function; | 🟩 Simple debugging and calibration. |
WORKING PRINCIPLE
The working principle of an ultrasonic level gauge is that an ultrasonic pulse emitted by a transducer (probe) is reflected back from the surface of the measured medium. Part of the reflected echo is received by the same transducer and converted into an electrical signal. The ultrasonic pulse propagates at the speed of sound, and the time interval from emission to reception is proportional to the distance from the transducer to the surface of the measured medium.
The relationship between this distance S, the speed of sound C, and the transmission time T can be expressed by the formula: S = C × T / 2. Because the emitted ultrasonic pulse has a certain width, the reflected wave in a small area close to the transducer overlaps with the emitted wave and cannot be identified, making it impossible to measure the distance.
This area is called the measurement blind zone,and the size of the blind zone is related to the operating frequency of the ultrasonic level gauge.
| The reference plane for measurement is the lower edge of the probe. | ||||||||
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APPLICATION AREAS
Ultrasonic level gauges are widely used in various fields, including the petroleum industry, chemical industry, water treatment, municipal water supply and drainage, industrial storage tanks, river and lake monitoring, shipbuilding and marine engineering, pharmaceutical industry, construction engineering, agricultural irrigation, heating, and environmental protection. They are used to measure parameters such as the liquid level, density, and temperature of various liquid media.
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INSTALLATION GUIDE
| 🟩 Installation method | ||
| In open environments, a bracket installation method is generally used, secured with the instrument's built-in flange. A 60mm diameter circular hole is cut at the installation location in the pool or tank. The instrument probe is inserted, and then the flange is tightened from bottom to top. Installation must ensure that the probe face is horizontal to the liquid surface being measured. The probe emits a wave that hits the liquid level and reflects back to the probe. After receiving the wave, the time from emission to reception is calculated to obtain the measurement distance L. The current liquid level H is obtained by subtracting the measurement distance L from the instrument's installation height TH. | ||
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| The instrument's range refers to the distance the instrument can measure. The installation height TH should be less than the range. The instrument's blind zone refers to the area near the probe that the instrument cannot measure. The distance between the highest liquid level and the probe should be greater than the blind zone. For example, if the blind zone is 0.5m, then the distance between the highest liquid level and the probe must be greater than 0.5m. For example: Range: 6 meters, Blind Zone: 0.45 meters, Actual Measurement Range: 0~5.55 meters. The probe emits waves through a diffusion process, meaning it has a directional angle. Care must be taken during installation, otherwise it may hit protrusions on the pool wall or the edge of the channel. |
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| 🟩 Bracket installation | ||
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| Bracket-mounted for installing 15-meter ultrasonic level gauges. | ||
| 🟩 Flange installation | ||
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| Flange type for installation of 15-meter ultrasonic level gauges | ||
| 🟩 Container takeover | ||
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| Container connector length: The probe must extend at least 10mm beyond the connector. | ||
| 🟩 Moisture proof | ||
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| For installations in outdoor or humid environments, the cable seal should be tightened, and the cable should be bent downwards into a U-shape at the inlet. | ||
| 🟩 Container takeover | ||
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| Foam can form on the surface of certain liquid media due to feeding, agitation, or other processes within the container, attenuating the transmitted signal. If foam causes measurement errors, the sensor should be installed in a waveguide or a guided wave radar level gauge should be used. Guided wave radar level gauges are unaffected by foam and are the best choice for this application. When there is agitation in the tank, the instrument should be installed as far away from the agitator as possible. If foam or waves are generated due to agitation, a waveguide installation should be used. | ||
| 🟩 Airflow | ||
| If there is a strong airflow inside the container, such as when it is installed outdoors and the wind is strong, or if there is an air vortex inside the container, it is recommended to install the sensor inside a waveguide tube, or use a pulse radar level gauge or a guided wave radar level gauge. | ||
| 🟩 Waveguide installation | ||
| The diameter of the air vent is (5-10) mm. Using a waveguide (or bypass tube) for installation can avoid the influence of obstacles, foam and air eddies inside the container on the measurement. | ||
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ELECTRICAL CONNECTION
| 🟩 Power supply method | ||||||||||
| The 4~20mA/HART (two-wire) power supply and output current signal share a single two-core cable. Refer to the technical datasheet for specific power supply voltage ranges. For intrinsically safe models, a safety barrier must be installed between the power supply and the instrument. | ||||||||||
| The 4~20mA/HART (four-wire) power supply and current signal each use a separate two-core cable. Refer to the technical datasheet for specific power supply voltage ranges. | ||||||||||
| Standard instruments can output current via grounding. Explosion-proof instruments must have floating current outputs. The instrument and grounding terminal must be properly grounded. Grounding is typically connected to the tank's grounding point; for plastic tanks, it should be connected to the nearest earth. | ||||||||||
| 🟩 Installation of connecting cables | ||||||||||
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EXPLOSION PROOF CONNECTION
This product's explosion-proof marking: ExdⅡC T 4 Gb. The ultrasonic level gauge uses an aluminum housing with an internal sealed structure to ensure that sparks generated in the event of a transducer or circuit failure will not be released. This product is suitable for continuous level measurement of flammable media with an explosion-proof rating of ExdⅡC T4 Gb or lower.
This product must be powered by a safety barrier when used in explosion-proof environments.
All cables must be shielded cables, with a maximum length of 600m. Distributed capacitance ≤ 0.1μF/km, distributed inductance ≤ 1mH/km.
The ultrasonic level gauge must be grounded during installation.
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