Integral Non-corrosion-proof Ultrasonic Level Meter

     Integral Ultrasonic Level Meter 

Measuring Principle  

The working principle of the ultrasonic level meter is that an ultrasonic pulse emitted by the Transducer (probe) is reflected back when it encounters the surface of the measured medium, and part of the reflected echo is received by the same Transducer and converted into an electrical signal. The ultrasonic pulse propagates at the sound velocity. The time interval from emission to reception of the ultrasonic pulse is proportional to the distance from the Transducer to the surface of the measured medium. The relationship between this distance value S, the sound velocity C, and the transmission time T can be expressed by

the formula: S=CxT/2.

Since 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 recognized, so its distance value cannot be measured. This area is called the measurement blind zone. The size of the blind zone is related to the model of the ultrasonic level meter.

Features   

Thanks to the advanced microprocessor and unique echo processing technology, the ultrasonic level meter can be applied in various complex working conditions. The "echo curve" function enables the instrument to correctly confirm the true echo under conditions with multiple echoes, obtaining accurate measurement results.

The Transducer has a built-in temperature Sensor, which enables temperature compensation of the measured value.

The ultrasonic Transducer adopts patented acoustic matching technology, allowing its transmitting power to be radiated more effectively and improving the signal strength, thereby achieving accurate measurement. 

Instrument Overview

Application: liquid level measurement in various industrial and water conservancy fields

Supply voltage: 12VDC, 24VDC, 220VAC±10%

Measuring range: 2m; 5m, 10m, 15m, 20m, 25m, 30m, 35m, 40m, 45m, 50m

Process connection: determined by measuring range

Main unit housing material: ABS, PC

Sensor housing material: ABS, PVDF, PTFE

Process temperature: -25～+60℃

Process pressure: 0～3bar

Wiring system: four-wire system;

Analog signal output: 4-20mA;

Digital signal output: RS232 or RS485;

Control output: 2 relay channels

Protection Rating: IP67

Measurement accuracy: 0.5%

Display: LCD display

Sensor to main unit cable length: none

1. Product Introduction

Ultrasonic level meter (for measuring material level and liquid level) is a non-contact, high-reliability, high-cost-performance level measurement instrument that is easy to install and maintain. It can meet most level measurement requirements without contacting the medium, and is a new-generation ultrasonic level meter developed by our company through years of effort and with fully independent intellectual property rights.

2. Commissioning

Since the on-site installation environments of instruments vary, the ultrasonic level meter must know the basic conditions of the required measurement before operation, such as measuring range, zero point, full scale, and on-site working conditions, etc.

3. Main Technical Specifications

Note: This series of ultrasonic transducers can also be customized according to customer requirements: high-pressure resistant, high-temperature resistant, small diameter, small blind zone, and other special transducers.

4. Installation Guide

4.1 Level meter mounting dimensions                    

(1) Integrated ultrasonic level meter, enhanced type

(2) Integrated ultrasonic level meter, explosion-proof type:

4.2 Installation Guide

4.2.1 Understanding Technical Terms

① Range: When selecting the instrument, the meaning of measuring range is very important. Please see the schematic diagram below.

② Beam angle and false echoes

The ultrasonic beam is focused by the transducer. The pulse beam is emitted like the beam of a flashlight; the farther away from the transducer, the larger the spread area.

Any object within the beam angle, such as pipes, brackets, welds, reinforcing ribs, stirring propellers, or wall-attached objects, will cause strong false echoes, especially objects closer to the transducer within the beam angle.

For example, a pipe 6 m from the transducer produces a false echo 9 times stronger than the same pipe 18 m from the transducer.

★ Try to keep the sensor axis perpendicular to the medium surface, and avoid any other objects (such as pipes and brackets) within the beam angle.

4.2.2 Measuring Range Selection

 The measuring range depends on the range of the ultrasonic probe. The range of the ultrasonic probe depends on the on-site working environment, the target to be measured, temperature, etc. Based on the table below, you can select the required measuring range in meters.

Signal attenuation calculation: if multiple conditions exist on-site, add up all these conditions to calculate the amount of signal attenuation.

· Slight filling 5...10dB

· Slight steam 5...20dB

· Temperature difference between probe and medium surface ≤40℃ 5...10dB

Total minimum 15dB, maximum 40dB.

In this case, if the actual maximum measuring range is 5m, then an ultrasonic level meter with a 50m range needs to be selected for measurement.

4.2.5 Measuring Liquids

4.2.5.1 Flat-Top Tank

Flat-top tanks generally have a very short nozzle. The reference surface of the nozzle is the lower face of the flange. Provided that the nozzle length is ≤60mm, the nozzle inner diameter is ≥100mm, and the inner wall of the nozzle is smooth without burrs or protrusions, measurement is possible after installation when the probe's transmitting surface is 3cm below the lower face of the flange.

The ideal installation is to mount the instrument directly on the flat-top vessel without using a nozzle; the circular opening on the vessel is sufficient to secure the mounting flange or universal joint. The probe's transmitting surface is below the reference surface.

4.2.5.2 Arched Tank Roof

For arched tanks, the instrument should preferably not be installed at the center of the tank roof, but rather at 1/2 or 2/3 of the roof radius (provided that a certain distance from the tank wall is maintained). For ultrasonic pulses, the arched tank roof acts like a convex lens. If the probe is installed at the focal point of the convex lens, it will receive all false echoes. Therefore, installation of the sensor probe at the center of the arched tank roof should be avoided as much as possible.

On most arched tank roofs, the length of the nozzle plus the flange is 150-180mm, while the probe of the ultrasonic level meter below the threads is not long enough (a lengthened probe can be customized by our company so that the probe's transmitting surface is below the bottom of the nozzle).

Fuzhou Dayu Electronics——Ultrasonic Level Meter, ultrasonic level meter, ultrasonic transducer,ultrasonic Doppler Flow Meterand other ultrasonic industrial instrument manufacturers.