Hydrological current meter is the core equipment in the field of hydrological monitoring, which provides key data support for water resources management, flood control and disaster reduction and ecological protection by accurately measuring water flow speed.

1. Product Introduction

The flow velocity meter (hereinafter referred to as the portable flow meter) is a general-purpose instrument for measuring flow velocity in hydrological surveys, used to measure the time-averaged flow velocity at predetermined measuring points in the water cross-sections of rivers, lakes, reservoirs, canals, etc.

The flow meter meets the relevant national standards such as GB/T 11826-2019 (rotor type flow meter).

The flow meter is widely applicable to hydrological surveys, hydraulic investigations, agricultural irrigation, runoff experiments, etc., and can also be used in the power industry, environmental protection, mining, transportation, geology, scientific research institutes, municipal and other industries for related flow or discharge monitoring.

The portable flow meter is mainly composed of LS1206B type propeller flow sensor, flow meter, and 0.4m×4Ф16 measuring rod. The whole instrument is placed in a high-grade aluminum alloy password box. Connect the power line, and the flow in each open channel can be measured, and the flow rate is automatically displayed.

The instrument has a simple structure, is lightweight and convenient to use, consumes little power, has a complete set of functions, a high degree of automation, and is stable and reliable, in accordance with the national standard for open channel flow measurement. It is equipped with a 60-degree high-temperature propeller and is a new type of portable flow rate measuring instrument in China.

Second, Technical Parameters:

Speed measurement formula: V = KN/T + C (m/s) (automatic calculation)

Propeller rotation diameter: Ф70mm

P pitch of propeller hydraulic b: 120mm (theoretical value)

Takeoff speed V0: 0.05m/s

测速范围：0.06-8.00 m/s

Discharge error: ≤1.5%

Output signal: Magnetic switch contact on-off signal

Signal number/rotor speed: 2/1 (2 signals per revolution)

Display: 4x16 LCD display

Measurement method: rod positioning measurement (also cable suspension positioning measurement)

Temperature range: -25℃-55℃, humidity ≤ 90% RH

Power supply: DC8.4V (rechargeable battery), can work continuously for more than 40 hours after being fully charged

Three, Measurement Principle:

This instrument is designed based on the principle of the velocity-area method for measuring flow in an open channel. The flow rate Q can be obtained by measuring the velocity, where Q = V·S (S is the cross-sectional area).

1. Flow rate determination:

When measuring the flow rate, the hydrodynamic force drives the propeller-type rotor flow meter to rotate, and the built-in signal device generates a revolution signal, which is calculated by the following formula: V = KNT + C (m/s) (automatic calculation)

V: Average flow velocity (m/s) during the measuring period.

K: Pitch of propeller

C: Flow meter constant

T: Duration of flow measurement (unit is S)

N: Number of signals in time period T

When this instrument is used, K and C are both constants, and when measuring the flow, the flow rate can be calculated as long as T and N are measured.

2. Calculation of flow:

The flow rate is determined by the velocity-area method of open channel flow measurement, where the velocity is measured first and then multiplied by the cross-sectional area to obtain the flow rate.