Integrated non-corrosion-resistant ultrasonic open channel flow meter without calibration rod

1. Product Introduction

Ultrasonic open channel flow meterUsed with a measuring weir/flume to measure water flow in an open channel. Mainly used to measure flow at sewage treatment plants, discharge outlets of enterprises and institutions, urban sewers, and channels in farmland water conservancy, etc.

Because our instruments use ultrasound through the air for non-contact measurement, they have higher reliability and durability than contact-type instruments under viscous or corrosive liquid conditions.

Integrated open channel flow meterExterior and dimension drawings of the display instrument

2. Principle Description

This series of instruments directly measures the liquid height in a channel or trough. When used for open channel flow measurement, a measuring weir/flume is installed in the open channel. The weir/flume converts the flow rate in the open channel into a liquid level. The instrument measures the water level in the weir/flume and then calculates the flow rate according to the water level-flow relationship of the corresponding weir/flume. 

1. Principle of ultrasonic liquid level measurement

The ultrasonic pulse emitted by the transmitting ultrasonic transducer propagates through the propagation medium to the measured liquid surface, is reflected, and then returns through the sound propagation medium to the receiving ultrasonic transducer. The time taken for the ultrasonic pulse from emission to reception in the sound propagation medium is measured. Then, based on the sound velocity in the medium, the distance from the transducer to the liquid surface can be calculated, thus determining the liquid level. Therefore, we can calculate the distance D from the probe to the reflecting surface as D ＝ C*t/2 (divided by 2 because the sound wave actually travels a round trip from emission to reception; D is distance, C is sound velocity, t is time). The liquid level value can then be obtained by subtraction.

2. Flow measurement principle of the measuring weir/flume

In a smooth open channel, the higher the flow rate, the higher the liquid level; the lower the flow rate, the lower the liquid level (see Figure 2.1). The flow rate can be derived by measuring the water level. In ordinary open channels, the relationship between flow rate and water level is affected by the channel slope ratio and surface roughness. Installing a measuring weir/flume in the channel creates a throttling effect, establishing a fixed relationship between flow rate and liquid level in the open channel. This relationship mainly depends on the structural dimensions of the weir/flume, minimizing the influence of the channel.

Commonly used measuring weirs/flumes include the right-triangular weir, rectangular weir, and Parshall flume.

Figure 2.1  Common measuring weirs/flumes and the relationship between water level and flow variation

When using an ultrasonic open channel flow meter, the water level-flow relationship of the matching measuring weir/flume must be known during installation.

The water level-flow relationship of the measuring weir/flume can be found in the national metrological verification regulation "Open Channel Weir/Flume Flow Meter" JJG711-90. This manual excerpts a part of it (Section 6, Measuring Weir/Flume). For the Parshall flume, once the throat width b is known, the corresponding formula can be used to calculate the water level-flow relationship.

The right triangular weir also uses the corresponding formula to calculate the water level-flow relationship.

Rectangular weirs also have corresponding formulas. However, they also depend on the installed channel dimensions. When determining the water level-flow relationship, the rectangular weir is related to channel width B, opening width b, and upstream weir crest height p.

If you are not familiar with calculating the water level-flow of the measuring weir and flume, notify the instrument manufacturer of the measuring weir and flume parameters used. The manufacturer will help with the calculation. Note that the above parameters related to determining the water level-flow relationship should be provided simultaneously.

3. Main Technical Specifications

Function: divided into integrated type and separate type

Measuring range: 0.1L/s～99999.99m/h

Cumulative flow: maximum: 4290000000.00 m³

Maximum liquid level range: 3 m

Liquid level measurement accuracy: 0.5%

Resolution: 3mm or 0.1% (whichever is greater)

Display: Chinese LCD display, or English LCD display

Flow measurement accuracy: standard weirs/flumes are 1～5% (weirs/flumes and channels meeting national standard requirements), non-standard weirs/flumes are 10～60%.

Analog output: 4-wire 4～20mA/600Ω load

Relay output: (optional) 2 sets AC 220V / 5A or DC 24V / 5A,

Power supply: standard 24VDC 100mA; optional 220V AC+15% 50Hz.

Power supply: (optional) 12VDC, battery power, solar power

Operating environment temperature: main unit -20～+60℃, Sensor -20～+80℃

Operating environment pressure: standard atmospheric pressure

Operating environment humidity: ≤90%RH, non-condensing

Process temperature: -20～80℃;

Process pressure: standard atmospheric pressure

Communication：optional 485，232 communication，MODBUS protocol

Protection Rating: display instrument IP66，probe IP68

Probe cable：integral type has no cable，split type comes standard with 10m cable

 Sensor（ultrasonic probe）selection instructions：

No. 1-5 Parshall flumes are recommended to use M48×2 probe，small beam angle，not easy to hit the wall or corner of the Parshall flume and form false signals。

M48×2 probe has small blind zone，only 10cm，mounting bracket can be made lower。

No. 6-24 Parshall flumes are recommended to use M78×2 probe，blind zone only 25cm，and signal is stronger than M48×2 probe，suitable for measuring flow in large channels。

 Split-type open channel Flow MeterExterior and dimension drawings of the display instrument

 4、Product advantages

The circuit design uses high-quality power modules from the power supply section, and components are imported, highly stable and reliable devices, fully comparable with instruments of the same type.
1、The patented acoustic intelligent technology software can perform intelligent echo analysis，no need for any debugging or other special steps，this technology has the functions of dynamic thinking and dynamic analysis。
2、The patented acoustic intelligent technology greatly improves the accuracy of the instrument，liquid level accuracy reaches 0.3%，and can resist various interference waves。
3、This instrument is a non-contact instrument，does not directly contact the liquid，therefore the failure rate is low。The instrument provides multiple installation methods，users can completely perform instrument calibration through this manual。
4、All input、output lines of the instrument have lightning protection and short-circuit protection functions。

5、Application scope

Integral ultrasonic open channel Flow Meter cooperates with Parshall flume、triangular weir、rectangular weir to measure water flow in channels，mainly used to measure sewage treatment plants、sewage discharge outlets of enterprises and institutions、urban sewers flow and farmland water conservancy irrigation channels etc。
Current customers include：Wuhu Huayan Water、Daqing Oilfield、Chongqing Xingbo Chemical、Shengli Oilfield、Hubei Dongfang Chemical、Nantong Economic Development Zone Sewage Treatment Plant etc。

 6、Installation instructions

 Figure      Product installation probe diagram    

On-site open channel weir tank installation photo        Triangular weir installation

 Rectangular weir installation    as shown below

Parshall flume installation

 Ultrasonic open channel Flow Meter documentation link is as follows：

/Admin/Plugins/kindeditor/attached/file/20170926/20170926172348_3907.zip

Fuzhou Dayu Electronics－－Ultrasonic open channel flow meter、Sewer Flow Meter、River Flow Meter、ultrasonic Doppler Flow MeterA manufacturer of these, and also your considerate product consultant！

If you have any doubts about the above information or need to understand any aspect of the products in depth，please call the hotline 0591-28082552 or add corporate QQ:2187169532

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