Water Flow Meter

1.Water Flow Meter Product Introduction

Water Flow Meter has the advantages of simple structure, lightweight and convenient, power saving, stability and reliability, and meets the standard of open channel flow measurement.Water Flow Meter (portable flow meter for short) is a general instrument for measuring flow velocity in hydrological tests. It is used to measure the average flow velocity over a period of time at predetermined measuring points in water sections such as rivers, lakes, reservoirs, and canals.

Water Flow Meter complies with relevant national standards such as GB/T 11826-2019 (Rotor Flow Meter).

Water Flow Meter is widely used in hydrological tests, water conservancy surveys, farmland irrigation, runoff experiments, etc. It can also be used in hydropower, environmental protection, mining, transportation, geology, scientific research institutes, municipal administration and other industries to monitor relevant flow rate or flow.

Water Flow Meter is mainly composed of propeller flow velocity sensor, flow velocity calculator and measuring rod. The whole set of instruments is placed in a high-grade aluminum alloy password box. After connecting the signal line, the flow velocity in each open channel can be measured and the flow velocity can be automatically displayed.

The instrument has a simple structure, is lightweight and convenient, consumes little power, has complete functions, is highly automated, stable and reliable, complies with national open channel flow measurement standards, and is equipped with a 60-degree high-temperature propeller. It is a new type of portable flow velocity measuring instrument in China.

2. Water Flow Meter Technical Parameters:

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

Propeller rotation diameter: Ф125mm

Propeller hydraulic pitch b: 200mm (theoretical value)

Starting speed V0: 0.03m/s

Speed measurement range: 0.04-10.00 m/s

Flow measurement error: ≤1.5%

Output signal: Magnetic excitation switch contact on/off signal

Number of signals/rotor revolutions: 1/20 (LJ20A type) (1 signal per 20 revolutions); 1/1 (LJ20C type) (1 signal per 1 revolution)

Display: 4×16-bit LCD

Measuring method: measuring rod positioning measurement (cable hanging positioning measurement is also possible)

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

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

3. Water Flow Meter Measurement Principle:

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

1. Flow rate measurement:

When measuring flow velocity, the propeller rotor flowmeter is driven by hydraulic power to rotate, and the built-in signal device generates a rotation signal. The flow velocity is calculated by the following formula: V = KN/T + C (m/s) (automatic calculation)

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

K: hydraulic pitch of propeller blades

C: Flow meter constant

T: flow measurement duration (in seconds)

N: Number of signals in period T

When the instrument is in use, K and C are both constants. When measuring flow, the flow rate can be calculated by simply measuring T and N.

2. Flow calculation:

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