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E-mail
312534289@qq.com 467090947@qq.com
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Phone
18761882890/13814089468
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Address
15-20 Xingda Road, Nanjing Yangtze River Industrial Development Zone
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Nanjing Zhuoma Electromechanical Co., Ltd
LB70 series rotary cup flow meter, flow rate measuring instrument, LS series flow meter
NegotiableUpdate on 04/14
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Overview
LB70 series rotary cup flowmeter I. Main purpose and scope of application LB70 series rotary cup flowmeter is a traditional, vertical axis rotor flowmeter used to measure the average flow velocity of a predetermined measuring point in a certain water passage section during a certain period of time. The LB70 series rotary cup flowmeter complies with relevant national standards such as GB/T11826-2002 "Rotary flowmeter". The LB70 series rotary cup flowmeter is generally suitable for measuring low flow rates (such as small irrigation channels), and can also be used for runoff experiments, hydraulic experiments, etc. 2、 Main technical performance and parameters: 1) Rotary cup return
Product Details
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LB70 series rotary cup flowmeter
1、 Main purpose and scope of application
The LB70 series rotary cup flowmeter is a traditional, vertical axis rotor flowmeter used to measure the average flow velocity at a predetermined measuring point in a certain water crossing section during a certain period of time.
The LB70 series rotary cup flowmeter complies with relevant national standards such as GB/T11826-2002 "Rotary flowmeter".
The LB70 series rotary cup flowmeter is generally suitable for measuring low flow rates (such as small irrigation channels), and can also be used for runoff experiments, hydraulic experiments, etc.
2、 Main technical performance and parameters
1) Rotating cup rotation diameter: Φ 130mm
2) Spiral cup hydraulic pitch b: 70mm (theoretical value)
3) Starting speed v0:0.016m/s (LB70-1C)
0.06m/s（LB70-2C、LB70-2D）
4) Critical speed vk: about 0.13m/s
(Based on the actual verification value. According to statistical analysis, vk is much smaller than the above value.). ）
5) Speed measurement range: 0.02m/s~2m/s (LB70-1C)
0.1m/s～4m/s（LB70-2C、LB70-2D）
6) Output signal: on-off signal of switch contact
7) Signal number/rotor speed: 1/1 (LB70-1C, LB70-2C) (1 signal per 1 revolution)
1/5 (LB70-2D) (1 signal every 5 revolutions)
8) Switch contact capacity: DC U ≤ 24V; I≤120mA
9) Contact operation times: 1 × 107
10) Relative mean square error of the entire line m: | m | ≤ 1.5% (for v ≥ vk)
11) Relative error δ: | δ | ≤ 5% (used when v<vk)
12) Working water environment: water temperature ranging from 0 ℃ to+40 ℃
Water depth ranging from 0.1m to 100m
Suspended sediment concentration ≤ 1kg/m3
13) Storage environment: Temperature -25 ℃ to+55 ℃
Humidity ≤ 90%
3、 Structural features and working principle
The LB70 series rotary cup flowmeter consists of a rotary cup component (rotor component), yoke component, support component, reed switch component, (reduction) gear component, and tail wing component (see Figure 1).
The rotary cup is used to passively sense water flow and rotate around a vertical support axis under the driving force of water flow. Its rotational diameter is Φ 130mm, and the theoretical hydraulic pitch is 70mm.
The yoke serves as the support frame for the rotor and is used for the installation and fixation of the flowmeter during operation. Its installation aperture is Φ 20mm.
The supporting components are installed on the yoke to provide supporting force to the rotor.
The reed switch component is used to receive magnetic excitation from the rotor system and provide flow meter signals to the outside.
The tail wing components play a directional and balancing role during flow rate operation.
When the flowmeter is working, the rotating cup is driven by the water flow to rotate. The magnetic steel installed on the upper end of the rotary cup component rotates synchronously with it, exciting the reed switch to generate an output signal. For the LB70-2D model, its magnetic steel is installed inside the gear components, and for every 5 revolutions of the rotary cup rotor, the flowmeter generates an on/off output signal.
4、 Installation, use, and maintenance
4.1 Installation
(1) Installation of measuring rod
The LB70 series rotary cup flowmeter is generally installed using a measuring rod when measuring shallow water flow. The diameter of the measuring rod is 20mm, and the length of each section is 1m (users can determine the total length of the measuring rod and select the number of sections according to their actual needs); The measuring rod is marked with a number every 10cm as a marker for the installation position of the depth and velocity meters; There is a pointer (compass) above the measuring rod to align the flowmeter with the flow direction. When the flow rate is high, tail wing components should be installed to ensure accurate orientation and stability of the flowmeter.
Note: It is recommended that the total length of the measuring rod should not exceed 4m.
(2) Installation of suspension rods and cables
When the measuring point is relatively deep, the suspension method is generally used to measure the flow, and the flowmeter is installed on a suspension rod, cable or lead fish. When the water depth and flow velocity are relatively low, suspension rods are often used for installation; Otherwise, suspension installation will be used. When using a fixed suspension rod, the flowmeter should be aligned with the flow direction.
4.2 Usage and Precautions
The use of flow meters should strictly follow the relevant provisions of SL443-2009 "Hydrological Cableway Testing Specification", GB50179-93 "River Flow Testing Specification" and other relevant hydrological testing specifications.
Before use in water, the following tasks should be carried out:
(1) Sensitivity testing
1) Gently and evenly blow air towards the rotating cup, and the cup should be able to rotate easily without any jamming;
Note: This test largely depends on the user's actual experience and should be repeatedly tested and mastered proficiently for future comparison.
2) Quickly rotate (or blow) the cup, there should be no emergency stop phenomenon.
(2) Signal testing
Using counters or speakers for testing, the signal should be accurate and reliable.
For the LB70-2D model, its signal duty cycle is approximately 2/5.
(3) The exposed signal wiring should be wrapped tightly with insulating tape or adhesive tape to prevent water from becoming the signal medium.
(4) When the flow rate is high, tail wing components should be installed to facilitate orientation and balance. When installing with suspension cables, attention should be paid to the state of the flow meter underwater. By adjusting the position of the internal balance screw of the tail wing component, ensure that the longitudinal axis of the flow meter is parallel to the direction of water flow (in a horizontal state in the water).
(5) Check whether the installation of the flowmeter is stable at all stages.
