Rotameter Flow Meters-Metal Variable Area Flow Meters
Rotameter Flow Meter is a process instrument used to measure the volume flow of pipeline gas or liquid. It adopts the variable area measurement principle. It has the characteristics of small size, large detection range, and easy use. It can be used to measure the flow of liquids and gases. It is especially suitable for medium flow measurement with a low flow rate and small flow rate.
The Rotameter Flow Meters produced by our Sino-Inst support the customization of DN15~DN200. Can be configured with explosion-proof, intelligent transmitter, output 4-20mA signal, and HART protocol. Two alarm outputs can be configured.
Optional external power supply or built-in 3.6V lithium battery power supply;
Rotameter Flow Meters Technical Parameters
Measuring range
Water (20℃): 1-200000 L/h Air (20℃, 0.1013MPa): 0.03~4000m³/h
Turndown
Standard type 10:1, special type 20:1
Accuracy
Gas 2.5%FS; Liquid 1.5%F.S
Pressure Level
Standard type: DN15-N50 4.0MPa; Special type: DN15-N50 25 MPa; The pressure rating of the jacket is 1.6MPa. For special models, please consult and confirm before selecting and ordering.
pressure loss
2kpa-20kpa
Medium temperature
Standard type: -40℃~100℃; PTFE: 0℃~120℃; High temperature type: 100℃~450℃;
Remote transmission type: 40℃~185℃ (the liquid crystal will not be damaged), the liquid crystal normally works at -30℃~80℃; local pointer type: -40℃~100℃
Connection Type
Connection method: flange connection standard HG20592-2010, DIN 2501 standard flange; or produced according to customer requirements; Threaded connection: produced according to diameter or customer requirements; Sanitary clamp connection: produced according to diameter or customer requirements;
Cable interface
The flameproof type is 1/2NPT internal thread; other M20*1.5 internal thread;
Power supply
Standard type: 24VDC two-wire system 4-20mA (12VDC-32VDC); Alarm type: 24VDC three-wire system 4-20mA (18VDC-28VDC); AC type: 85-265VAC50Hz; Battery type: 3.6V, 7.5AH battery, used continuously for three years;
Load characteristics
Two-wire system: RLmax=50*(-12)Ω=600Ω@24V Alarm type: the maximum load resistance is 200Ω AC type: the maximum load resistance is 200Ω
Please contact and consultant with the manutadurer
Structure of rotameter flow meter
This series of metal tube rotameter flow meters mainly consists of two parts: measuring tube and indicator.
The measuring tube includes tapered tube, guide, stopper, float and other components.
The indicator includes a magnetic follow-up system, pointers, dials, circuits and other components. Divided into local type and intelligent type.
For the local type, the following magnet in the local indicator is coupled with the magnet in the float to rotate, and at the same time the pointer is driven to indicate the flow rate at this time through the dial.
For the intelligent type, the following magnet in the intelligent indicator is coupled with the magnet in the float to cause rotation. At the same time, it drives the sensing magnet and pointer. The changes in the magnetic field are converted into electrical signals through a magnetic sensor, which is then processed by AD conversion, digital filtering, temperature compensation, microprocessor processing, D/A output, and LCD display to display the instantaneous flow and accumulated flow.
Rotameter flow meter working principle
The structure of a rotameter flow meter is a vertical tapered metal tube whose cross-sectional area gradually expands from bottom to top. There is a rotor (or float) made of metal or other materials that can rotate freely. The fluid to be measured enters from the bottom of the metal tube and flows out from the top.
When the fluid flows through the vertical tapered tube from bottom to top, the rotor is acted upon by two forces: one is the vertical upward pushing force, which is equal to the pressure difference generated by the fluid flowing through the annular cross-section between the tapered tube and the rotor.
The other is the vertical downward net gravity, which is equal to the gravity on the rotor minus the buoyancy force of the fluid on the rotor. When the flow increases so that the pressure difference is greater than the net gravity of the rotor, the rotor rises. When the pressure difference is equal to the net gravity of the rotor, the rotor is in equilibrium. That is to stay in a certain position.
A reading is engraved on the outer surface of the metal tube. According to the dwell position of the rotor, the flow rate of the measured fluid is read.
The rotameter is a variable cross-section constant pressure differential flowmeter. The pressure difference acting on the upstream and downstream of the float is a constant value. The annular cross-sectional area between the float and the tapered tube changes with the flow rate. The position of the float in the tapered tube reflects the flow rate.
Rotameter With mA Signal
Sino-Inst’s rotameters can be configured with a mechanical pointer display, suitable for measurement sites where no power supply is available. Alternatively, an intelligent display can be configured. When powered, various signal outputs are available:
The most commonly used 4-20mA signal provides users with simpler and more effective flow monitoring support. The flow signal can be transmitted remotely to the control room, or connected to a control valve for flow control.
Advantages:
Metal float flowmeter is suitable for small pipe diameters and low flow rates. It is suitable for measuring low flow rate and small flow. Taking liquid as an example, the flow rate is between 0.5-1.5m/s.
The float flowmeter has a wide flow range, generally 10:1. Pressure loss is low.
The float flowmeter can be used at lower Reynolds numbers. By choosing a float with a viscosity-insensitive shape, the flow coefficient remains constant when the Reynolds number changes, that is, changes in fluid viscosity do not affect the flow coefficient.
The float flowmeter has no requirements for the upstream straight pipe section. Most float flowmeters are installed in pipelines with vertical flow from bottom to top.
Disadvantages:
The application of float flowmeter is limited to small and medium pipe diameters. Ordinary full-flow float flowmeters cannot be used for large pipe diameters. The maximum diameter is generally DN200mm.
When the fluid used is different from the factory calibration fluid, the flow indication must be corrected. Float flowmeters for liquids are usually calibrated with water, and gases with air. If the density and viscosity of the actual fluid used are different, the flow rate will deviate from the original graduation value, and conversion corrections must be made.
The correct reading method of metal rotor flowmeter is:
Stand directly in front of the flow meter with your eyes parallel to the float. Move your eyes horizontally to the left until you see the outline of the float touching the positioning line. The intersection of the positioning line and the horizontal scale in the middle of the float is the corresponding reading value.
Of course, our Sino-Inst Rotameter Flow Meters have electronic smart displays as an option. Can display instantaneous flow and accumulated flow. It can also support signal output, etc.
There are obvious differences between Rotameter Flow Meters and electromagnetic flow meters in terms of working principles, structural features and application scenarios. When choosing a suitable flow meter, we need to make a judgment based on the actual situation.
Working Principle
The metal rotor flow meter works based on the buoyancy principle. When the fluid flows through the rotor, the rotor rises or falls due to the buoyancy of the fluid. The displacement of the rotor is proportional to the flow rate of the fluid, so the flow rate of the fluid can be measured.
The electromagnetic flow meter works based on Faraday’s law of electromagnetic induction. When the fluid flows through the sensor, an induced potential proportional to the fluid flow rate is generated. The flow rate of the fluid is calculated by measuring the magnitude of the induced potential.
Structural Features
The structure of the metal rotor flow meter is relatively simple, mainly consisting of a rotor and a conduit. The rotor moves up and down in the conduit, and the buoyancy of the fluid causes the rotor to rise or fall.
The structure of the electromagnetic flow meter is relatively complex. It is mainly composed of a sensor, a measuring tube and a converter. The sensor generates a magnetic field, and when the fluid flows through the sensor, an induced potential is generated. The flow rate of the fluid is calculated by measuring the magnitude of the induced potential.
Application scenarios
Metal rotor flowmeters are suitable for measuring low conductivity liquids, such as water, milk, etc. It can be used to measure small flow rates.
Electromagnetic flowmeters are suitable for measuring conductive liquids, such as acids, alkalis, brine, etc. It has high measurement accuracy and can be used in large-scale industrial production processes. For example, in the petrochemical industry, electromagnetic flowmeters can be widely used for the measurement and monitoring of raw liquids.
Maintenance
The maintenance of metal rotor flowmeters is relatively simple. Generally, it is necessary to clean the conduit and rotor regularly and check whether the sealing is good. In some cases, the rotor or conduit may need to be replaced.
The maintenance of electromagnetic flowmeters is relatively complicated. Generally, the sensor and measuring tube need to be cleaned regularly to prevent scaling or contamination. In addition, it is necessary to check whether the magnetic field of the sensor is normal. If abnormal conditions are found, the sensor may need to be replaced or repaired.
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Metal tube rotameter is a common flow measurement instrument that is widely used and can be used to measure media such as liquids, and gases. It is a flow meter with simple structure, high precision and strong reliability, so it can be used in various occasions.
For example, in high-temperature, high-pressure and corrosive media environments, high-temperature and corrosion-resistant materials can be used to manufacture metal tube rotor flowmeters to ensure long-term stable operation.
The metal tube rotameter produced and supplied by our Sino-Inst is simple to install and easy to operate. It does not require complicated maintenance and upkeep, reducing operation and maintenance costs and improving work efficiency. Moreover, it can also cooperate with various control systems to realize automatic control and improve the degree of automation of production.
If you need to purchase Rotameter Flow Meters-Metal Variable Area Flow Meters, or have related technical questions, please feel free to contact us.
Zhang Wei, possesses 20 years of experience as an automation instrumentation engineer, specializing in the research, design, installation, commissioning, and maintenance of automation instruments.
Face to various instrument communication protocols (such as Modbus, Profibus, etc.), with solid hardware circuit design and software programming skills (proficient in C language and PLC programming). Has extensive project experience; projects he has led and participated in have all achieved outstanding results, improving product accuracy, reducing costs, and increasing production efficiency.
Possesses excellent communication and coordination skills and a strong team spirit, enabling him to quickly respond to customer needs and provide high-quality automation instrumentation solutions.
Rotameter Flow meters ( Variable Area ) | Sino-Inst
Rotameter Flow Meter is a process instrument used to measure the volume flow of pipeline gas or liquid. It adopts the variable area measurement principle. It has the characteristics of small size, large detection range, and easy use. It can be used to measure the flow of liquids and gases. It is especially suitable for medium flow measurement with a low flow rate and small flow rate.
Product SKU: Rotameter Flow Meters-Metal Variable Area Flow Meters
