What are the methods for measuring river flow without weir channel flowmeter

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1. How to detect the flow velocity of water

Water flow velocity detection method:

1. Flow meter method: The flow meter method uses a flow meter to measure the water flow velocity and calculates the flow rate by multiplying the flow velocity by the cross-sectional area. The measurement results of the flowmeter method can serve as a standard for calibrating or verifying other flow measurement methods. Applicable conditions: When the water depth is greater than 10cm and the flow velocity is not less than 0.05m/s, a flow meter can be used to measure the flow velocity.

2、 Float method: Float flow measurement method is a simple flow measurement method that measures the cross-section of a waterway based on the observed float drift velocity, in order to estimate the cross-sectional flow rate. Applicable conditions: The channel length is not less than 10 meters, there is no bending, and the bottom wall is smooth.

3、 Thin walled weir method: The thin-walled weir method has high measurement accuracy. The commonly used methods include thin-walled triangular weir method, thin-walled rectangular weir method, and thin-walled trapezoidal weir method. a、 Applicable conditions of thin-walled triangular weir method: It is suitable for measuring water flow with a head of 0.05 m ≤ H ≤ 0.35 m and a flow rate Q ≤ 0.1 m3/s. b、 Applicable conditions for thin-walled rectangular weir method: When measuring the water depth H passing through the weir, it should be carried out at a location greater than 3H upstream of the weir mouth.

4、 Babbitt trough method: Babbitt trough, also known as Bacher trough, has the characteristics of low head loss, unsuitable sedimentation of debris, and high water measurement accura

5、 Volumetric method: Within a certain period of time, the sewage in the channel is introduced into a container with a calibrated volume. The flow rate Q is obtained by dividing the net volume difference △ V at the end of time and the starting time by the time difference △ t. The measurement is repeated several times and the average value is taken. Applicable conditions: Small flow rate and non-standard drainage channels.

7、 Flow meter method: Directly select targeted professional flow meters for measurement. According to the structural principle of flow meters, they can be divided into the following types: volumetric flow meters, impeller flow meters, roll up differential pressure flow meters, electromagnetic flow meters, ultrasonic flow meters, etc.

2. The principle of open channel flowmeter and selection of weir channel - Tangshan Dafanghui Instrument

The open channel flowmeter adopts the principle of "liquid level method", which measures the liquid level in the standard water weir channel and calculates the flow value by combining the formula.

1. Working principle of open channel flowmeter. An open channel flowmeter consists of three parts: a converter, a liquid level sensor, and a standard water weirs. Liquid level measurement: The liquid leve

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