External-mounted Ultrasonic Liquid Level Gauge

1. Product Brief Introduction:

The external-mounted liquid level gauge adopts leading digital signal processing technology, avoiding the influence of container wall thickness and achieving true non-contact measurement of liquid level height inside the sealed container. The sonar sensor (probe) is installed directly below the outer wall (bottom) of the tested container, without the need to open holes in the tested container. It is easy to install, enables online installation and debugging, and does not affect production. It can measure the liquid level of various flammable, explosive, toxic and other hazardous media, strong acids, strong alkalis and various pure liquids in high-temperature and high-pressure sealed containers.

2. Product Features:

(1) Pioneering the two-wire system
We have overcome various technical difficulties and successfully developed a two-line external mounted liquid level gauge. The two-wire external mounted liquid level gauge achieves ultra-low power consumption, meets the industrial field two-wire instrument standard, simplifies on-site wiring requirements, and is more conducive to safety and explosion prevention.
(2) Non contact measurement of liquid level, safe
Realize true non-contact measurement, making installation and maintenance significantly simpler and more convenient.

(3) Advanced automatic power control algorithm, capable of achieving small blind spots or no blind spots
When the liquid level is high, use higher power, and when the liquid level is low, use lower power to automatically switch the probe power. It not only increases the measurement range, but also reduces the measurement blind spot. Thus, small blind spots or even measurements without blind spots have been achieved.
(4) Ultra high measurement accuracy, up to 1 ‰ FS
By using the built-in bottom boundary false wave suppression function, automatic power control algorithm, automatic sampling rate control algorithm and other functions, the measurement accuracy is greatly improved, with an accuracy of 1cm in some practical cases.
(5) Simultaneous measurement of liquid level boundary
It is possible to measure both liquid level and boundary position simultaneously. Can configure analog, 485, and Modbus outputs as boundary or liquid level.
(6) Equipped with bottom boundary false wave suppression function
In some cases, there may be other media at the bottom of the storage tank, and the interface formed by them can affect the transmission of signals, thereby affecting normal measurements. This function will automatically identify false waves, skip false waves, and search for the true echo signal. As 
(7) Real time measurement of tank temperature and remote transmission of temperature signals
Real time measurement of tank temperature and remote transmission of temperature signals through analog or digital signals
(8) Real time temperature calibration to improve measurement accuracy
It can measure the temperature of the storage tank in real time and perform a certain degree of temperature compensation. For common media such as liquid ammonia, propylene, propane, LPG, etc., it can also perform sound velocity compensation to further improve measurement accuracy.
(9) Automatic calibration and self diagnostic functions
The automatic calibration function of the external mounted liquid level gauge overcomes the problem of reduced accuracy after long-term use of traditional liquid level gauges. It has increased the reliability and stability of the external mounted liquid level gauge in terms of its own working status and hardware diagnostic function.
(10) Pipeline calibration, automatically enabled
When the liquid level is below half, the calibration probe on the side cannot perform normal calibration. The level gauge automatically activates pipeline calibration and performs real-time calibration through the inlet and outlet pipelines to further improve measurement accuracy.
(11) Full range real-time tracking, no need to restart when empty tank is filled with liquid
Whether it is an empty tank or liquid, regardless of the level, the level gauge can track the full range in real-time.
(12) Installation and debugging are greatly simplified
The liquid level gauge is highly intelligent, greatly reducing on-site installation and debugging work, achieving a foolproof installation.
(13) There are multiple options for displaying remote indicators on the liquid level gauge
The liquid level gauge can display remote liquid level, liquid level percentage, volume, mass, etc.

(14) With relay output
It can achieve single point alarm or dual point alarm output.

2. Working Principle:

The external mounted liquid level gauge adopts the principle of sonar ranging, using a dedicated probe attached to the outside of the container wall to collect sonar signals. With dedicated sonar wave processing technology as the system core and advanced high-speed signal processing technology, the liquid level inside the container is calculated using Shaanxi Acoustic Technology's dedicated algorithm. The calculated liquid level value is displayed locally and outputs a remote transmission signal. The instrument can output measurement results to the control center through (4-20) mA analog signals, HART, RS-485 and other interfaces, and can also be debugged online through HART, RS-485, infrared and other interfaces.

External mounted level gauges are particularly suitable for non-contact measurement of various toxic substances, strong acids, strong bases, and liquids (liquid chlorine, liquid ammonia, vinyl chloride, liquefied petroleum gas, liquefied natural gas, propane, butane, ethylene, propylene, butadiene, gasoline, kerosene, diesel, salt acid, sulfuric acid, aqua regia, etc.) in sealed containers. Some measured media are shown in the table below. The instrument adopts explosion-proof design and can be applied in situations where explosion-proof is required. It can be widely used in many industries such as petroleum, mining, power plants, chemical plants, water treatment plants, sewage treatment stations, agricultural water use, environmental monitoring, food (brewing industry, beverage industry, additives, edible oil, dairy products), flood control, hydrological monitoring, etc.

3. Technical Specifications:

Power supply: 220VAC and 24VDC (AC/DC dual-use)
Transmission distance:

(1) Remote transmission type ≤ 300m (four wire system: any wire can be used as long as it can meet mechanical strength)
(2) Nearby type ≤ 30m (using cable TV RF cable, manufacturer's standard wiring of 3 meters)
Signal output: 4-20mA signal output Standard communication interface 232 or 485 (note: the stolen communication interface is non-standard)
Control output: 2 sets of 4 channels, programmable relay output
Transmission power: any segment from 0 to 60m
Blind zone: 0.35-1.00m (the blind zone is proportional to the transmission power)
Launch angle: 6 ° to 10 ° (the size of the launch angle is proportional to the launch power)
Resolution: Range ≤ 10m: 1mm. Range ≥ 10m: 10mm
Protection level: transducer: Ip68
Accuracy: 0.25-0.5%
Environmental temperature: Secondary table: -25 to+55 ℃
Transducer temperature:

(1) Far energy type -25~+55 ℃
(2) Nearby type -25~+70 ℃

4. Installation: