结构解剖 Structural Anatomy of a Metal Tube Float Flowmeter
1. High-temperature structure (G-type): High-temperature structure (G-type) is used for medium flow measurement when the temperature of the medium is too high or too low and it is necessary to take thermal insulation measures on the measuring tube. The high-temperature structure increases the distance between the measuring tube and the indicator to increase heat dissipation and increase the thickness of the thermal insulation material to ensure that the indicator works within the allowed ambient temperature range. Selection is "G" type. The G-type metal tube float flow meter can measure the flow of medium with a temperature of -80 ℃-+ 300 ℃. 2. Structure with damper device (Z type): The damper structure type is used for medium flow measurement when the inlet flow (pressure) of the flowmeter is unstable, especially for gas measurement. 3. Jacket type structure (T type): The jacket type structure is used to measure the flow rate of the medium that needs heat tracing or cooling (such as high viscosity and easy to crystallize). By heating or cooling the medium in the jacket, the low boiling point and low freezing point fluids are not vaporized and crystallized. HG20594-97 DN15 PN1.6 flange is used as standard for heat tracing medium lead-in and lead-out connection. Other flange specifications can be specified with the manufacturer. The pressure level of the jacket is 1.6MPa. 4. High-pressure type structure (Y type): The high-pressure type structure is used for the flow measurement of the pressure of the measured medium greater than the standard pressure level. At present, the maximum pressure of FFM64 series can reach 32MPa. In addition, the high-pressure type flowmeter can provide a built-in magnetic filter type, and the installation height is 350mm. The maximum pressure for FA, FB and FC models is 10 MPa.
Jinhu Dongxiang Instrument Co., Ltd. is a domestic key set of measurement and control engineering units, designated production supporting enterprises of the Ministry of Chemical Industry, Metallurgy, Power, Light Industry. The main products are metal tube float flowmeter quotation, precession vortex gas flowmeter, external clip type ultrasonic flowmeter and other products. Our company has liquid and gas verification equipment for the production of flow meters. The accuracy of the equipment can reach level 0.2, and it can provide various liquid and gas flow meters for the same industry or users.
技术参数测量范围:水(20℃)1-200000 l／h 空气(20℃，0．1013MPa)0．03－4000m3／h 参见流量表，特殊流量可订制量程比：标准型10：1 特殊型20：1 Technical parameters of metal tube rotor flowmeter Measurement range: water (20 ° C) 1-200000 l / h air (20 ° C, 0.113MPa) 0.03-4000m3 / h See flow meter, special flow rate can be customized Type 10: 1 Special type 20: 1
Accuracy: Standard type 1.5 Special type 1.0 Pressure level: Standard type: DN15-DN50 4.0MPa DN80-DN200 1.6MPa
Special type: DN15-DN50 25MPa? DN80-DN200 16MPa
Jacket pressure rating is 1.6MPa
Special models should be negotiated with the factory before selecting and ordering pressure loss: 7kPa-70kPa
Medium temperature: standard type: -80 ℃-+ 200 ℃: PTFE: 0 ℃ -85 ℃
High temperature type: up to 400 ℃
Medium viscosity: DN15: <5mPa.s (F15.1-F15.3)
Ambient temperature: LCD type -30 ℃ － + 85 ℃
Pointer －40 ℃ － + 120 ℃
Connection form: standard type: DIN2501 standard flange special type: any standard flange or threaded cable interface specified by the user: M20 * 1.5
Power supply: standard 24VDC two-wire system 4-20mA (10.8VDC-36VDC)
AC type: 85-265VAC? 50HZ
Alarm output: upper or lower limit instantaneous flow alarm standard type: open collector output (maximum internal impedance 100 ohms)
Special type: relay output (maximum pulse output of contact capacity: cumulative pulse output, minimum interval 50 milliseconds) LCD display: instantaneous flow rate display value range: 0-50000
Accumulated flow display value range: 0-99999999
Protection level: IP65
Explosion-proof mark: intrinsically safe iaⅡCT6 flameproof dⅡCT6
故障分析 Failure analysis of metal tube float flowmeter
1. Pointer jitter: 1. Slight pointer jitter: Generally caused by media fluctuations. This can be overcome by increasing damping. 2. Moderate pointer jitter: Generally caused by the state of media flow. For gas, it is generally caused by the unstable operating pressure of the medium. Can use voltage stabilization or flow stabilization device to overcome or increase the air flow damping of the float flowmeter. 3. Vigorous pointer jitter: Mainly due to the pulsation of the medium, the unstable air pressure, or the pressure, temperature, and flow rate of the gas operating state given by the user do not match the actual status of the float flowmeter, and there are large differences that cause the float flowmeter to exceed the range.
Second, the pointer stops at a certain position: the main reason is that the float of the float flowmeter is stuck. Generally, because the float flowmeter opens the valve too quickly during use, the float quickly hits the stopper upwards, causing the stopper to deform and the floater stuck. However, it is not ruled out that the float is stuck because the float guide rod and the stop ring are not concentric. During processing, the instrument can be removed, the deformed stopper can be removed and reshaped, and check whether it is concentric with the guide rod. If not, you can correct it, then install the float, push the float by hand, and feel that the float is smooth. Yes, in addition, the float flowmeter must be installed vertically or horizontally, and cannot be tilted, otherwise it will easily cause card meters and bring errors to the measurement.
Third, the measurement error is large: 1. The installation does not meet the requirements; for the vertical installation of the float flowmeter, the vertical angle must be less than 20 degrees; for the horizontal installation of the float flowmeter, the horizontal angle must be less than 20 degrees; There should be no ferromagnetic objects in the space; the installation position should be far away from the valve reducing port, the pump outlet, and the turning point of the process pipeline. To maintain the requirements of the first 5D after 250mm straight pipe section. 2. Large density change of liquid medium is also a cause of large error. Before the instrument is calibrated, the medium is converted according to the density given by the user, and converted to the water flow under calibration state for calibration. Therefore, if the medium density changes greatly, it will cause a large error in the measurement. The solution is to bring the changed medium density into the formula, convert it into an error correction coefficient, and then multiply the flow rate measured by the flow meter by the coefficient to replace the real flow rate. 3. Since the gas medium is greatly affected by temperature and pressure, it is recommended to use the temperature and pressure compensation method to obtain the true flow rate. 4. Due to long-term use and pipeline vibration and other factors, the floating flowmeter sensing magnetic steel, pointer, counterweight, rotating magnetic steel and other moving parts are loose, causing large errors. Solution: first push the pointer by hand to verify. First press the pointer at the RP position to see if the output is 4mA and whether the flow rate display is 0%, and then verify according to the scale. If a discrepancy is found, the position of the component can be adjusted. Generally requires professional adjustment, otherwise the position will be lost, and it needs to be returned to the factory for correction. Fourth, no current output: 1. First see if the wiring is correct. 2. Whether the LCD has a display, if there is no output, the output tube is mostly broken, and the circuit board needs to be replaced. 3. Lost calibration value. Due to the failure of E2PROM, the calibration data of the instrument is lost, and no output current will be caused, and the current will remain unchanged. Solution: The data recovery operation is available. If it does not work, you can set the data in password 2000 and then the data in password 4011. The method is to push the pointer to calibrate the data from RP to 100%.
V. No on-site display 1. Check whether the wiring is correct. 2. Check whether the power supply is correct. 3. Reinstall the LCD module, and check the contact is not correct. 4. For multi-wire power supply mode, check whether terminals 12 and 13 are connected to ammeter or short circuit. Six, the field LCD always displays 0 or full scale
1. Check the set range and zero parameters in the 2000 password. ZERO is required to be less than the value of SPAN, and the two values cannot be equal. 2. Check if the sampling data comes up, push the pointer with your hand to see the sampling value change. If there is no change, the sampling circuit of the circuit board is generally faulty and the circuit board needs to be replaced. Seven, the alarm is incorrect 1. Check that the deviation setting d value cannot be too large. 2. Whether the logic function is correct in the FUN function. HA-A stands for positive upper logic. LA-A means lower limit positive logic. 3. Check the alarm value setting size in SU. 4. If the LCD bar code is correct and the output has no action, you can check whether the external power source and the negative pole of the external power source are connected to the negative pole of the instrument. 5. The circuit board is faulty. Replace the circuit board. Eight, the cumulative pulse output is incorrect:
1. Check whether the alarm value of the cumulative pulse output is set to zero. 2. The circuit board is faulty. Replace the circuit board.