1Equipment Composition

IIEquipment principle

The product has three functions: measuring average flow velocity, measuring water depth, measuring water temperature, and can display cross-sectional flow rate.

The water temperature measurement uses a temperature probe, the water depth measurement uses an imported high-precision pressure sensor, and the flow velocity measurement is carried out through ultrasound

The wave probe (transducer) emits and receives ultrasonic wave signals and performs corresponding calculation and processing to obtain them.

Average flow velocity measurement：The measurement of flow velocity is achieved by emitting and receiving ultrasonic signals through an ultrasonic probe (transducer) and performing corresponding measurements

countObtained through computational processing:transducer1The transmission frequency isf1Ultrasonic signals are emitted from underwater at a certain angle towards the surface of the water, and upon contact

watercentreAfter the suspension of particles or bubbles, the frequency shifts andf2The frequency is reflected back to the transducer2This is what Doppler will do,f2

givef1thisThe difference is the Doppler frequency differencefdLet the fluid flow rate bevThe ultrasonic velocity iscDoppler frequency shiftfdProportional to fluid velocityv.

waterThere will beA large number of impurity particles and bubbles, with each reflected particle corresponding to a Doppler frequency shiftfdBy conversion, the flow velocity can be obtained,

These large quantitiesThe average velocity of particles, also known as the average velocity of fluids.

IIIApplication scope

4equipment installation

The probe should be installed in a straight section of the channel with a fixed cross-section, and the length of the straight section is preferably 15-20 times the hydraulic radius of the channel (usually the width of the channel) (the longer the straight section, the higher the measurement accuracy). Generally, a straight section with 10 times the hydraulic radius is required upstream, and a straight section with 5 times the hydraulic radius is required downstream. There should be no overcurrent obstacles (such as water gates, weirs, etc.) within this distance range to ensure the uniform and stable flow state of the water flow at the front end of the probe.

The probe should be installed as close to the bottom of the channel as possible. When there are impurities and pebbles with water plants growing or rolling at the bottom of the channel, the installation position can be raised to avoid the probe being covered by sediment and water plants at the bottom of the channel or colliding with pebbles; The specific height of the probe from the bottom of the channel is best between 50mm and 150mm, depending on the lowest measured water level of the channel. When the channel water depth is high and has a certain minimum water level, for ease of installation, simply install the probe 0.5 times below the minimum water level.

·Flow rate:
·Range: 20mm/s to 6000mm/s.
·Accuracy: ± 1% of the measured flow rate.
·Resolution: 1mm/s.

·Temperature:
·Range: 0 ℃ to 60 ℃.
·Resolution: 0.2 ℃.

·Water level:
·Range: 0-10m.
·Resolution: 1 mm.
·Accuracy: ± 0.5% of the measured water level.

·Traffic:
Accuracy: ± 2% of the measured flow rate.

·Power supply:
12V DC or 220V AC.

·Output interface:
Standard RS232, RS485, 4-20mA.

·Communication protocol:
Modbus。

·Data storage capacity:
Collect a record every 10 minutes and store data for more than 6 months.

·Operating temperature:
The water temperature ranges from 0 ℃ to 60 ℃.

·Shell material:
PC or PVC plastic.

·Shell protection level:
IP68。

·Reliability:
MTBF≥25000h。

·Size:
(220 × 87 × 30) mm (probe).
(257 × 179 × 70) mm (terminal).
10m (standard length of communication cable, can be extended to 1000m).