Portable current meter

1. Product introduction of portable flow meter

The portable flow meter is also called a portable flow meter or a flow meter. The portable flow meter is a portable ultra-small flow meter suitable for flow rate monitoring in water conservancy and hydrological stations, farmland irrigation, open channels, ditches, rivers, tunnels, groundwater in factories and mining areas, etc. The portable current meter is a universal instrument for measuring flow velocity in hydrological surveys. It is used to measure the average flow velocity at predetermined measuring points in rivers, lakes, reservoirs, canals and other water-crossing sections.

This flow meter complies with relevant national standards such as GB/T 11826-2019 (rotor flow meter).

This 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 related flow rates or flows.

The portable flow meter mainly consists of a propeller flow sensor, a flow calculator, and a measuring rod. The complete set of instruments is placed in a high-grade aluminum alloy password box. By connecting the signal line, the flow rate in each open channel can be measured and the flow rate will be automatically displayed.

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

2. Technical parameters of portable flow meter:

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 switch contact on-off signal

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

Display: 4×16-bit LCD display

Measurement method: Measuring pole positioning measurement (cable suspension positioning measurement is also available)

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

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

3. Measurement principle of portable flow meter:

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

1.Flow velocity measurement:

When measuring the flow rate, the propeller-type rotor flow meter is driven by hydraulic power to rotate, and the built-in signal device generates a revolution signal. The flow rate 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: Blade hydraulic pitch

C: flow meter constant

T: flow measurement duration (unit: S)

N: Number of signals in T period

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

2. Calculation of flow rate:

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