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Trough weir type open channel ultrasonic flowmeter
Trough weir type open channel ultrasonic flowmeter
Product details
Trough weir type open channel ultrasonic flowmeter
overview
JD-900 seriesWeir type open channel flowmeterIt is an instrument used to measure the liquid flow rate of self flowing non full pipes and open discharge channels.Open channel flowmeterThe application field includes urban water supply channels, power plant cooling water diversion and drainage channels, sewage treatment inflow and discharge channels, chemical liquids and wastewater discharge channels of industrial and mining enterprises, as well as water conservancy engineering and agricultural irrigation channels. Production and testing standards are based on the National Technical Supervision Bureau《Open channel weir channel flowmeter》Verification regulation JJG771-1990.
◆ answer use 
● Water supply and diversion
● Discharge of sewage and wastewater
Water conservancy engineering and agricultural irrigation
Urban sewage system
● Chemical liquids
◆ Working principle
When used for channel flow measurement, install a water measuring weir on the channel. The function of a water measuring weir is to convert the flow rate in the channel into the level of liquid. Measure the liquid level inside the tank with a level gauge, and use a flow converter (secondary meter) to calculate the liquid flow rate based on the liquid level flow relationship of each type of tank.
The larger the flow in the channel, the higher the liquid level in the trough and weir; The smaller the flow rate, the lower the liquid level. There is no definite correspondence between liquid level and flow rate in general channels. Because the same water depth and flow rate are also related to the cross-sectional area, slope, and roughness of the channel. Installing a weir in a channel, due to the smaller gap or contraction of the weir compared to the cross-sectional area of the channel, the correspondence between the upstream water level and flow rate of the channel mainly depends on the geometric dimensions of the weir. The same weir is placed on different channels, and the same liquid level corresponds to the same flow rate. The weir converts the flow into liquid level.
● flow converter
The flow converter receives the liquid level depth signal output by the level gauge, and calculates the instantaneous flow rate and cumulative flow rate through the weir based on the type and size of the weir, the relationship between liquid level depth and flow rate.
Wall mounted sensor Disk mounted sensor
● Convert to Chinese display and Chinese operation menu
● Data recording and storage
Before being searchable720Hours ago365Oh my god, before36Monthly and ten-year traffic data.
● High precision mathematical calculation models are applicable to standard or non-standard tanks and weirs
● Menu setting for weir type
Basher trough, equal width weir, rectangular weir,900 Triangle weir, no throat groove,P-BSlot.
●signal output
4～20mA,Accumulated quantity pulse,RS-485, can be connected (or embedded)GSM/GPRSThe module realizes wireless data transmission and can be matched with connectionsPrinting machine.
● Liquid level meter
Open channel flowmeterThere are generally two types of liquid level gauges used,Ultrasonic level gaugeandStatic pressure level gauge.
● Ultrasonic level gauge
The liquid level is measured using ultrasonic echo ranging method, and this liquid level gauge is an intelligent non-contact liquid level measuring instrument. Equipped with automatic power adjustment, increasing
Benefit control, temperature compensation, advanced detection and calculation techniques are adopted to improve the measurement accuracy of the instrument, suppress interference echoes, and ensure the authenticity of the measurement results. The liquid level gauge is fixedly installed above the water level observation point of the trough weir. Probe the head and aim it vertically at the water surface.
power supply: DC24V
output: four～20mA(four-wire system)、RS485
range: 0～2m, 0～5m，0～10m，0～15m
control:Two way relay
accuracy: 0.25%
ambient temperature:- 25℃～-55℃
protection grade: IP67
resolution: 1mm
Display mode: sixteenposition×2 LCDBacklight
Corrosion resistant integrated liquid level gauge
Installation hole size68mm
Shell material: high-strength engineering nylon（PA6 GF30）
● Static pressure level gauge
The static pressure level gauge consists of a pressure-sensitive element, a stainless steel housing, and a connecting cable. When the liquid density is constant, the liquid level height is proportional to the liquid pressure, and the liquid level height can be calculated by measuring the liquid pressure.
Measurement range:0～2m，0～5m，0～10m，0～100m(Cable type)
Accuracy level:0.5%
Medium temperature:-10℃～70℃
Power supply:DC 16～32V
Signal output:4～20mA(Two wire system)
Protection level:IP68
Shell material: stainless steel
Ultrasonic level gaugeNot in contact with the tested liquid, suitable for measuring sewage and corrosive liquids. The static pressure level gauge is immersed in the measured liquid and is suitable for measuring water quality with relatively pure solid particles.
When the water level measurement is affected by severe fluctuations in the water surface at the observation point of the equivalent water weir trough,When it is necessary to improve the accuracy of water level measurement, a static water well can be used. Due to the action of the connecting pipe, the water level in the static water well is the same as that in the measuring weir groove. Require the static water well to be square or circular, insideDiameter greater than0.5Rice.
◆ Measurement tank weir sensor
● parshall flume
parshall flumeIt is a rectangular cross-sectional short throat groove composed of a contraction section upstream in the direction of water flow, a throat section, and a diffusion section downstream.
parshall flumeAccording to the width of the throat, it can be divided into three types: small groove, standard groove, and large groove.
parshall flumeFlow measurement range0.3～335000m3/hDetermine the structural dimensions of the Bacher trough based on the minimum and maximum flow rates. due toparshall flumeIt needs to be embedded in the channel on site, so there are requirements for the minimum dimensions of channel width and height when the flow range is constant.
Table of correspondence between minimum channel size and traffic volume
type
Minimum channel size
(Width x Height x Length) mmMinimum flow rate
（m3/h）maximum flow
（m3/h）
small
type200×250×700
0.30
20
260×300×800
0.7
50
300×500×950
2.8
115
450×650×1550
5.4
400
600×800×2900
9.0
904
treetop
accurate
type880×1000×2950
12.6
1440
1200×1000×3100
16.2
2300
1300×1100×3100
45.0
3100
1450×1100×3100
90.0
4000
1600×1100×3200
108
4500
1720×1100×3350
108
5400
2000×1100×3400
126
7200
type
Minimum channel size
(Width x Height x Length) mmMinimum flow rate
（m3/h）maximum flow
（m3/h）
treetop
accurate
type2300×1100×3400
162
9000
2700×1100×3650
288
10800
3100×1100×3800
342
12900
3400×1100×4000
360
14400
big
type4800×1300×7050
576
29800
5700×1600×8300
684
52800
7700×1900×12000
828
90000
9200×2200×13200
1116
136000
10800×2200×13500
1368
17000
12400×2200×14100
1656
203000
15600×2200×15000
2160
270000
19000×2200×16300
2700
335000
● No throat grooveA throat free groove is a rectangular cross-sectional groove formed by the intersection of an upstream uniform contraction section and a downstream uniform diffusion section, without parallel throat sections.
Flow measurement range without throat groove2.5～10800m3/h.
Table of correspondence between minimum channel size and traffic volume
| type | Minimum channel size (Width x Height x Length) mm |
Minimum flow rate (m)3/h） | Maximum flow rate (m)3/h） |
| 1 | 320×620×1000 | 2.5 | 288 |
| 2 | 420×620×1000 | 5.4 | 576 |
| 3 | 520×620×1000 | 7.2 | 864 |
| 4 | 620×620×1000 | 10.8 | 1190 |
| 5 | 620×620×1820 | 18 | 1140 |
| 6 | 820×920×1820 | 36 | 2920 |
| 7 | 1020×920×1820 | 57 | 4430 |
| 8 | 1220×920×1820 | 72 | 5940 |
| 9 | 920×1020×2720 | 49 | 2600 |
| 10 | 1220×1020×2720 | 93.6 | 5300 |
| 11 | 1520×1020×2720 | 140 | 8000 |
| 12 | 1820×1020×2720 | 190 | 10800 |
● P-Btrough
P-BA trough is a trapezoidal cross-sectional measuring trough embedded in a circular pipe. It is used to throttle a part of the circular pipe to measure the water flow rate in a non full pipe state.
Flow measurement range90～42000m3/h
● triangular weir rectangular weir Equal width weir
triangular weirRectangular weirs and equally wide weirs are collectively referred to as thin-walled weirs. A thin-walled weir refers to a thin-walled plate (baffle) with a certain shape gap installed perpendicular to the direction of water flow in a channel. If the shape of the gap is triangular, it is called a triangular weir; if the shape is rectangular, it is called a rectangular weir; if there is no gap and it is the same width as the channel, it is called an equal width weir.
900Measurement range of triangular weir flow0.72～6480m3/hRectangular weir flow measurement range5～176400m3/hMeasurement range of equal width weir flow2.8～277000m3/h.
◆ Selection of measuring water tank weir 
●When selecting multiple types of weirs, a certain type of weir should be determined based on the existing channel earthwork size on site, with the principle of minimizing construction volume as much as possible.
●When settling silt and debris, Bacher troughs or throat free troughs should be selected.
●Angle weirs, rectangular weirs, and equal width weirs have greater resistance to water flow, and solid matter is easily deposited on the upstream side, but the production cost is lower; The resistance of water flow in Bacher troughs and throat free troughs is low, and solid matter is not easily deposited, resulting in high production costs.
●The material of the water tank weir should be determined based on the corrosiveness of the liquid, and is generally selectedPVCCarbon steel, stainless steel.PVCThe material has anti-corrosion ability,But it should be protected from direct sunlight and aging,It is also not suitable for use in high-temperature media.
◆ Installation of measuring water tank weir
●The centerline of the water channel weir should coincide with the centerline of the channel to prevent water flow from deviating when entering the measuring water channel weir.●The flow state should be free flow. The water level downstream of triangular weirs, rectangular weirs, and equal width weirs should be lower than the weir crest.
●The upstream of the water tank weir should be greater than5A straight section that is twice the width of the channel, allowing the water flow to smoothly enter the measuring weir groove. There is no lateral deviation or the impact force formed by the slope of the channel.
●The installation of the measuring water tank weir on the channel should be firm. The connection with the side walls and bottom of the channel should be tight and not leak water. Make all the water flow through the measuring weir.
◆ Installation of liquid level gauge
●The selection of measuring weir should first consider which type of weir is suitable for the size of the on-site flow range.
● Ultrasonic level gauge
Ultrasonic level gauges should be installed directly above the center of the measuring tank or channel to ensure that the lowest point of the liquid level is measured. The distance between the highest water surface and the bottom of the sensor should be greater than0.2m.
● Static pressure level gauge
The static pressure level gauge is fixed on a bracket and placed in the water, with a distance from the bottom of the channel or measuring tank20mmTo prevent sludge from blocking the pressure tapping hole.
◆ Technical parameters
90 ° triangular weir
rectangular weir
Equal width weir
parshall flume
No throat groove
P-B slot
Flow range
0-6480
m3/h
0-176400
m3/h
0-277000
m3/h0-335000
m3/h
0-10800
m3/h
90-42000
m3/h
Accuracy (%)
3.0
5.0
Measuring liquids
Water, sewage, and other liquids
Weir channel material
Plastic, stainless steel, fiberglass, cement
signal output
keyboard
Wall mounted: 2 x 8 Panel mounted: 16 key
monitor
2 x 10 Chinese characters display with backlight.
Measurement function
Traffic, cumulative traffic, and running time.
Data storage
Can store data for the first 720 hours, the first 365 days, the first 36 months, and the first 10 years, including traffic and cumulative traffic.
ambient temperature
Converter:- 10～45℃
Ultrasonic sensor:- 20～45℃
protection grade
Wall mounted sensors: IP65； Disk mounted sensor IP52; Ultrasonic sensor: IP52。
ultrasonic sensor
Cable type
RVVP3 x 0.3
Working power supply
AC220V ± 10% DC12-36V power 1.5W
Converter dimensions
Wall mounted: 213 x 185 x 107mm Pan mounted: 160 x 80 x 250mm
Ultrasonic liquid level sensor
External dimensions
Converter weight
Wall mounted: 1.2k g Disk mounted: 1.0kg
Weight of ultrasonic sensor
1.5kg
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