1 Introduction Flow and temperature, level, pressure and other parameters are an important parameter that needs to be monitored at any time in the chemical production process. There are many methods of flow measurement. Different types of flowmeters such as electromagnetic flowmeters, vortex flowmeters, differential pressure flowmeters, and gasoline flowmeters can be selected for different media conditions. In the case of raw materials, intermediate products or products (finished products) involved in process assessment and/or cost accounting, the accuracy of the flow measurement has a great influence on the assessment or accounting results. It is necessary to select a higher-accuracy flow meter to complete the task of flow measurement. At this point, the gasoline flow meter shows great advantages and is the preferred target. This article briefly introduces the measurement principle, performance characteristics, selection and application of gasoline flowmeters.
2 Measurement Principles for Gasoline Flow Meters At present, most gasoline flow meters measure the mass flow rate of a fluid based on the Coriolis force principle. Coriolis force refers to the force that an object experiences when it moves linearly in a rotating system:
Fc=2*Δm(v*ω)
In the formula, Fc is the Coriolis force; Δm is the mass of the moving object; ω is the angular velocity; v is the radial velocity when rotating or shaking.
It can be seen that the Coriolis force is proportional to the mass Δm of the moving fluid and the velocity v, that is, proportional to the mass flow rate of the fluid, but not to the fluid temperature, pressure, viscosity, flow rate characteristics, and the like. The constant angular velocity ω can be replaced by the vibration of the flowmeter measuring tube. When the fluid flows through two parallel (or other forms) measuring tubes, the measuring tube is subjected to the reverse vibration by the Coriolis force. The Coriolis force generated in the measuring tube will cause the measuring tube to deform, resulting in a phase difference between the inlet and the outlet. The phase of the measuring tube can be measured by the phase sensor at the inlet and outlet.
3 Classification and characteristics of gasoline flow meters There are many manufacturers of gasoline flow meters. There are well-known companies such as Emerson Process Management Micro-motion, Endershaus, Foxboro, and Cologne. There are also domestic companies such as Beijing Jianzhong and Capital Technology Group.
According to different output signals of the instrument, it is divided into 4~20mADC HART regular signal, FF field bus digital signal, ProfiBus field bus digital signal, etc. Some gasoline flowmeters also have pulse signal output and alarm contact output; depending on the installation form, there is a split type And integrated type; according to different measuring mechanism structure, there is a single pipe, continuous single pipe, ω tube; according to the different measurement media can be divided into gas gasoline flow meter and liquid gasoline flow meter.
Take Micro-motion's products as an example to give a brief description of the characteristics and selection of gasoline flowmeters.
Micro-motion gasoline flowmeters are available in several sizes including E, F, D, R, H, and T types. E-type anti-interference ability, wide application range and the highest accuracy, liquid medium 0.1, gas medium 0.35, can be used for raw materials into the device measurement, trade measurement and other requirements of high accuracy occasions. F-type liquid medium 0.2, 0.5 gas medium, suitable for general occasions. Type D is a gasoline flow meter for special applications. The sensor not only has helium, Tefzel and other wetted parts, but also has the option of high temperature, high pressure, etc. The DS600's flow range can reach 680t/h. It is the most measurable range in the Micro-motion flowmeter family. R-type gasoline flow meter is a one-piece flow meter, liquid medium measurement accuracy of 0.5, although the accuracy is not too high, and its wetted material is only stainless steel, but because it is easy to install, economical and reliable, or get the user's Universally recognized. H-type and T-type are sanitary gasoline flowmeters made of stainless steel and titanium, which can meet the special surface treatment requirements of the hygienic food industry.
The characteristics of the products of other manufacturers vary, and the most cost-effective gasoline flow meter can be selected according to different occasions and accuracy requirements. However, it should be noted that the appropriate flow meter aperture should be selected according to the measured flow value so that the flow rate of the selected flow meter can be between 20% and 80% of the flowmeter's rated flow range.
4 Gasoline Flowmeter Installation Gasoline flowmeter installation There are no special requirements for the front and rear straight sections. However, the following conditions must be met:
(1) For liquid media, the flow meter should be at the low point of the pipe. Avoid vaporization of the medium due to low back pressure and affect the measurement results. For gaseous media, the flowmeter must not be placed at a local low point in the pipe to avoid measurement errors in the measurement tube.
(2) For liquid media, the media must be filled with piping during operation. Gas-liquid or liquid-solid two-phase fluids cannot be present in the measuring tube. If installed on a vertical pipe, fluid should flow from bottom to top. If it must flow from top to bottom, a restrictive orifice can be placed behind the flowmeter to prevent the measurement tube from being evacuated.
(3) The flow meter and the connecting flange must be completely aligned, otherwise it will bring external stress to the measuring tube and affect the measurement result.
(4) To avoid interference with the flowmeter due to strong electromagnetic fields, there must not be interference sources such as large motors near the flowmeter.
(5) When installing adjacent gasoline flow meters of the same type, the vibration frequency should be staggered to avoid the negative effects of resonance, and the distance between the two flow meters should be at least 4 times the length of the instrument.
(6) Pay attention to the inherent vibration frequency of the flowmeter phase measurement and the inherent vibration frequency of the pipeline, otherwise it will cause the measurement to fluctuate.
(7) Cut-off valves shall be installed before and after the flowmeter to facilitate zero correction before operation.
5 Problems and Solutions in the Use of Gasoline Flowmeters Shanxi Three-dimensional Group Co., Ltd. used multiple gasoline flowmeters including Micro-motion, Enders House, and Foxboro in its new installations. Some problems occurred in the course of operation and were resolved after careful analysis and taking corresponding measures.
(1) The flowmeter is located at the local high point of the entire pipe, and the measurement bubble collects air bubbles, and the measurement result has a large error. After changing the installation location, it works well;
(2) When the initial installation, there is no stop valve before and after the flowmeter, and the zero correction cannot be performed after the device is started. Increase the closing valve before and after, after the school is running normally;
(3) Concentricity of the pipes before and after the flowmeter causes the flowmeter to always have a flow output. Normal after re-arranging;
(4) The flowmeter is zero-shifted. Check that the resistance value of the detection coil and the drive coil is normal. After cleaning the inside of the sensor, it is normal. The reason is that the inner wall of the sensor causes zero drift;
(5) When the flowmeter is in the fault state, there will be a fault code display on the transmitter display. Refer to the maintenance instructions to find the corresponding processing method.
6 The display menus and operating methods of the gasoline flowmeter transmitter panel are not the same in all parts of the transmitter. However, the settings of the process parameters, range selection, output signal selection, and local display options can be set through the panel or the HART communicator. We will not go into details here. You can learn more about this by referring to the product manual. Gasoline flowmeter has the characteristics of high precision, multi-purpose media, good reliability, easy use, and low maintenance. The proportion of flow detection instruments is increasing, especially in the field of custody transfer. It is of great significance to understand and use gasoline flowmeters to ensure the safe and stable operation of chemical plants.
Gasoline flow meter diesel oil flow meter oil flow meter
2 Measurement Principles for Gasoline Flow Meters At present, most gasoline flow meters measure the mass flow rate of a fluid based on the Coriolis force principle. Coriolis force refers to the force that an object experiences when it moves linearly in a rotating system:
Fc=2*Δm(v*ω)
In the formula, Fc is the Coriolis force; Δm is the mass of the moving object; ω is the angular velocity; v is the radial velocity when rotating or shaking.
It can be seen that the Coriolis force is proportional to the mass Δm of the moving fluid and the velocity v, that is, proportional to the mass flow rate of the fluid, but not to the fluid temperature, pressure, viscosity, flow rate characteristics, and the like. The constant angular velocity ω can be replaced by the vibration of the flowmeter measuring tube. When the fluid flows through two parallel (or other forms) measuring tubes, the measuring tube is subjected to the reverse vibration by the Coriolis force. The Coriolis force generated in the measuring tube will cause the measuring tube to deform, resulting in a phase difference between the inlet and the outlet. The phase of the measuring tube can be measured by the phase sensor at the inlet and outlet.
3 Classification and characteristics of gasoline flow meters There are many manufacturers of gasoline flow meters. There are well-known companies such as Emerson Process Management Micro-motion, Endershaus, Foxboro, and Cologne. There are also domestic companies such as Beijing Jianzhong and Capital Technology Group.
According to different output signals of the instrument, it is divided into 4~20mADC HART regular signal, FF field bus digital signal, ProfiBus field bus digital signal, etc. Some gasoline flowmeters also have pulse signal output and alarm contact output; depending on the installation form, there is a split type And integrated type; according to different measuring mechanism structure, there is a single pipe, continuous single pipe, ω tube; according to the different measurement media can be divided into gas gasoline flow meter and liquid gasoline flow meter.
Take Micro-motion's products as an example to give a brief description of the characteristics and selection of gasoline flowmeters.
Micro-motion gasoline flowmeters are available in several sizes including E, F, D, R, H, and T types. E-type anti-interference ability, wide application range and the highest accuracy, liquid medium 0.1, gas medium 0.35, can be used for raw materials into the device measurement, trade measurement and other requirements of high accuracy occasions. F-type liquid medium 0.2, 0.5 gas medium, suitable for general occasions. Type D is a gasoline flow meter for special applications. The sensor not only has helium, Tefzel and other wetted parts, but also has the option of high temperature, high pressure, etc. The DS600's flow range can reach 680t/h. It is the most measurable range in the Micro-motion flowmeter family. R-type gasoline flow meter is a one-piece flow meter, liquid medium measurement accuracy of 0.5, although the accuracy is not too high, and its wetted material is only stainless steel, but because it is easy to install, economical and reliable, or get the user's Universally recognized. H-type and T-type are sanitary gasoline flowmeters made of stainless steel and titanium, which can meet the special surface treatment requirements of the hygienic food industry.
The characteristics of the products of other manufacturers vary, and the most cost-effective gasoline flow meter can be selected according to different occasions and accuracy requirements. However, it should be noted that the appropriate flow meter aperture should be selected according to the measured flow value so that the flow rate of the selected flow meter can be between 20% and 80% of the flowmeter's rated flow range.
4 Gasoline Flowmeter Installation Gasoline flowmeter installation There are no special requirements for the front and rear straight sections. However, the following conditions must be met:
(1) For liquid media, the flow meter should be at the low point of the pipe. Avoid vaporization of the medium due to low back pressure and affect the measurement results. For gaseous media, the flowmeter must not be placed at a local low point in the pipe to avoid measurement errors in the measurement tube.
(2) For liquid media, the media must be filled with piping during operation. Gas-liquid or liquid-solid two-phase fluids cannot be present in the measuring tube. If installed on a vertical pipe, fluid should flow from bottom to top. If it must flow from top to bottom, a restrictive orifice can be placed behind the flowmeter to prevent the measurement tube from being evacuated.
(3) The flow meter and the connecting flange must be completely aligned, otherwise it will bring external stress to the measuring tube and affect the measurement result.
(4) To avoid interference with the flowmeter due to strong electromagnetic fields, there must not be interference sources such as large motors near the flowmeter.
(5) When installing adjacent gasoline flow meters of the same type, the vibration frequency should be staggered to avoid the negative effects of resonance, and the distance between the two flow meters should be at least 4 times the length of the instrument.
(6) Pay attention to the inherent vibration frequency of the flowmeter phase measurement and the inherent vibration frequency of the pipeline, otherwise it will cause the measurement to fluctuate.
(7) Cut-off valves shall be installed before and after the flowmeter to facilitate zero correction before operation.
5 Problems and Solutions in the Use of Gasoline Flowmeters Shanxi Three-dimensional Group Co., Ltd. used multiple gasoline flowmeters including Micro-motion, Enders House, and Foxboro in its new installations. Some problems occurred in the course of operation and were resolved after careful analysis and taking corresponding measures.
(1) The flowmeter is located at the local high point of the entire pipe, and the measurement bubble collects air bubbles, and the measurement result has a large error. After changing the installation location, it works well;
(2) When the initial installation, there is no stop valve before and after the flowmeter, and the zero correction cannot be performed after the device is started. Increase the closing valve before and after, after the school is running normally;
(3) Concentricity of the pipes before and after the flowmeter causes the flowmeter to always have a flow output. Normal after re-arranging;
(4) The flowmeter is zero-shifted. Check that the resistance value of the detection coil and the drive coil is normal. After cleaning the inside of the sensor, it is normal. The reason is that the inner wall of the sensor causes zero drift;
(5) When the flowmeter is in the fault state, there will be a fault code display on the transmitter display. Refer to the maintenance instructions to find the corresponding processing method.
6 The display menus and operating methods of the gasoline flowmeter transmitter panel are not the same in all parts of the transmitter. However, the settings of the process parameters, range selection, output signal selection, and local display options can be set through the panel or the HART communicator. We will not go into details here. You can learn more about this by referring to the product manual. Gasoline flowmeter has the characteristics of high precision, multi-purpose media, good reliability, easy use, and low maintenance. The proportion of flow detection instruments is increasing, especially in the field of custody transfer. It is of great significance to understand and use gasoline flowmeters to ensure the safe and stable operation of chemical plants.
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