I. Open Channel Flowmeter Overview:

The LDM-51 Intelligent Open Channel Flow Measurement System is an open channel flow measurement system that utilizes a flow indicator, a velocity meter, and a level gauge to measure flow rates using the velocity-area method.

The LDM-51 Intelligent Open Channel Flow Measurement System is suitable for measuring flow rates in rectangular, trapezoidal open channels, and culverts for reservoirs, rivers, water conservancy projects, urban water supply, wastewater treatment, farmland irrigation, and water resources management.

Section 2: Working Principle of Open Channel Flow Meters

The LDM-51 Intelligent Open Channel Flow Measurement System, based on the velocity-water level calculation method, employs a servo water level tracking speed measurement system and a microprocessor to ensure the accuracy of speed measurement and computation. It is a new intelligent flow system that utilizes mathematical models for open channel flow measurement, tailored to the channel width and required measurement precision.

The LDM-51 intelligent open channel flow measurement system indicator's microprocessor calculates the average instantaneous flow rate of the channel based on the actual water level and velocity values from the sensors, as well as the pre-set geometric dimensions of the channel, slope coefficient, channel accuracy, hydraulic gradient, and vertical plane velocity correction coefficient, using a predetermined mathematical model.

Section 3: Characteristics of Open Channel Flow Meters:

• Open channel flowmeters have a wide measurement range (0.01-10 m/s), and flow measurement is not affected by the backwater from tributary surfaces.

• Open-channel flow meters are unaffected by floating objects, silt, bubbles, or significant water level changes. The velocity sensors are simple in structure, compact in size, easy to install, and do not impede water flow. Standard channels can be directly installed without modification, resulting in low installation and construction costs.

•Instrument display features: capable of simultaneously displaying measured data such as water level, average velocity across the cross-section, instantaneous flow across the cross-section, and cumulative flow.

Instrument Output Interface: Pulse (Frequency), RS485/Rs232, Current

• Alarm content: Water level exceeding limit, flow exceeding limit, flow rate exceeding limit, etc.

The open channel flow meter features data storage capabilities, allowing it to retain setting parameters and flow values even during extended power outages.

• The instrument features: wired and wireless data transmission capabilities (GPRS wireless communication).

• Communication protocols support the standard Modbus (RTU) protocol.

• In-built lightning protection function for the meter;

IV. Main Technical Specifications of Open Channel Flow Meters

• Measurement Accuracy: Flow Rate ±1.0%, Water Level ±0.5%, System ±2.5%

Power Consumption: <5VA

• Power: DC 12V/24V, AC 220V

• Measurement Range: Flow Rate 0.01-10 m/s

• Channel Width: 0.5-20m

• Channel Depth: 0.5-20m

• Accumulated traffic displays a higher value: 9,999,999,999

Instantaneous flow display shows a higher value: 10,000

Flow Rate Display: Higher Value 19.99

• Larger water level display: 19.999

V. Open Channel Flow Meter Installation Diagram:

(1) Electromagnetic Flow Rate - Ultrasonic Level Diagram

(2) Electromagnetic Flow Rate - Resistive Liquid Level Diagram

Section 6: Application Examples

1. Xinjiang Reservoir Agricultural Irrigation Installation Site

2. The Small Wave Reservoir Yellow River Diversion into Luo River Model Project

3. Installation Site of Northern Jiangsu Sewage Channels

4. Reservoir outlet tunnel installation site

5. Chongxi Sluice Open Channel Installation Site