HNTF-B portable velocity flow meter
I. Overview
Portable velocity flow meter (abbreviated portable flow meter) is designed for hydrological stations, factories, mines, environmental monitoring stations, agricultural irrigation, hydro-geological surveys and other departments open channel flow velocity measurements in the field and developed.
Portable flow meter is mainly composed LS1206B Propeller type velocity sensor (or other types of spinning cup Propeller Flow Meter), HNTF-B-type flow velocity meter, 0.4m × 4Ф16 measuring rods. A full set of advanced aluminum instrument in the password box. In use, as shown in Figure 1 are integrally assembled on signal line can be carried out in each open channel flow measurement, and automatically displays the flow rate.
The instrument structure is simple, lightweight and easy to use, low power consumption, full-featured, high degree of automation, stable and reliable, open channel flow measurement in line with national standards, is currently the new portable flow measurement instruments.
Second, the instrument's technical requirements
Propeller turning diameter: φ60mm
Propeller hydraulic pitch: H = 120mm
From instrument speed: VO ≤0.06m / s
Instrument speed range: 0.05 ~ 7m / s
Calibration accuracy: Formula mean square m ≤ disabilities 1.2%
V <0.2m / s, the relative error δ≤ disabilities 5%
Signal Frequency: Every two turn signals
Continuous working hours: 24h (sediment concentration 1Okg)
Display: 2 x 16 digit LCD display
Measurement: spindle positioning measurements (also rope hanging position measurement)
Temperature range: -10 ℃ ~ 45 ℃
Instrument Communication: RS232
The instrument calculates: automatic calculation of flow.
Instrument Storage: 99 measurement data.
Power: DC5V (5 18OOmA four NiMH rechargeable battery), fully continuous work more than 40 hours.
Third, the measurement principle
This instrument is designed according to the principles of open channel flow measurement of velocity area method, measure the flow velocity can be obtained Q = V? S (S for the cross-sectional area)
1 flow rate measurement:
Measured flow rate, driven by a hydraulic propeller rotating rotor flow meter, built-in signal means for generating revolution number signal, the flow rate is calculated by the following formula:
(K / b) N
V = ------ + C / a (m / s)
T
Where: V: average velocity flow measurement intervals (m / s)
b / K: hydraulic blade pitch
a / C: Flow Meter constant
T: flow measurement duration (in S)
N: T time period the number of signals
S: cross-sectional area
Q: Flow
When using this instrument, K / b, C / a are constants, measured flow, measured setting T N, can also be set S, can automatically calculate the velocity and flow.
2. Flow measurement:
Open channel flow measurement according to the flow velocity measurement area method, first measure the velocity multiplied by the cross-sectional area of the flow that was, HNTF-B instrument will automatically calculate the flow. At the same time it can store 99 measurement data.
