A gas flow meter is a meter that meters the flow of a gas. Installed in the pipeline to record the amount of gas flowing through. Can measure gas, air, nitrogen, acetylene, phosgene, hydrogen, natural gas, nitrogen, liquefied petroleum gas, hydrogen peroxide, flue gas, methane, butane, chlorine, gas, biogas, carbon dioxide, oxygen, compressed air, argon Gas, toluene, benzene, xylene, hydrogen sulfide, sulfur dioxide, ammonia, and the like.
The thermal gas mass flowmeter uses the principle of thermal diffusion, which is a technology with excellent performance and high reliability under severe conditions. Its typical sensing element consists of two thermal resistors (Platinum RTD), one is a speed sensor and the other is a temperature sensor that automatically compensates for changes in gas temperature. When two RTDs are placed in the medium, the speed sensor is heated to a constant temperature above ambient temperature.
Another temperature sensor is used to sense the temperature of the medium. The mass flow of gas through the velocity sensor is calculated by the amount of heat transfer from the sensing element. As the gas flow rate increases, the amount of heat carried away by the medium increases. The sensor temperature is reduced accordingly. In order to keep the temperature constant, it is necessary to increase the operating current through the sensor, which is proportional to the flow rate of the medium.
Flow meter is one of the large-scale instruments in process automation instruments and devices. It is widely used in metallurgy, electric power, coal, chemical, petroleum, transportation, construction, textile, food, medicine, agriculture, environmental protection and people's daily life. In all areas of the national economy, it is an important tool for developing industrial and agricultural production, saving energy, improving product quality, and improving economic efficiency and management level. It plays an important role in the national economy. In process automation instruments and devices, flow meters have two functions: as a test instrument for the process automation control system and a total meter for measuring the quantity of materials.
Energy is divided into primary energy (coal, crude oil, coalbed methane, petroleum gas and natural gas), secondary energy (electricity, coke, artificial gas, refined oil, liquefied petroleum gas, steam) and energy-carrying refrigerant (compressed air, oxygen, Nitrogen, hydrogen, water, etc. Energy metering is an important means of scientifically managing energy, achieving energy conservation and reducing consumption, and improving economic efficiency. Flow meters are an important part of energy metering. Water, artificial gas, natural gas, steam and oil use a very large number of flow meters, which are indispensable tools for energy management and economic accounting.
Environmental protection engineering
The emissions of flue gas, waste liquid, sewage, etc. seriously pollute the atmosphere and water resources, and seriously threaten the human living environment. The country regards sustainable development as a national policy, and environmental protection will be the biggest issue in the 21st century. Air and water pollution must be controlled, management must be strengthened, and management is based on quantitative control of pollution.
China is a country with coal as its main energy source. There are millions of chimneys in the country that continuously emit smoke into the atmosphere. Flue gas emission control is an important project to cure pollution. Each chimney must be equipped with a flue gas analysis instrument and a flow meter to form a flail emission monitoring system. The flow rate of flue gas is very difficult. The difficulty is that the chimney is large in size and irregular in shape, the gas composition changes indefinitely, the flow rate range is large, dirt, dust, corrosion, high temperature, and no straight pipe section.
There are five ways: railway, air, water and pipeline transportation. Although pipeline transportation has already existed, the application is not common. With the outstanding environmental protection issues, the characteristics of pipeline transportation have attracted people's attention. Pipeline transportation must be equipped with a flow meter, which is the eye for control, distribution and dispatch, and is an indispensable tool for safety monitoring and economic accounting.
The 21st century will usher in the century of life sciences, and industries characterized by biotechnology will develop rapidly. There are many substances that need to be monitored in biotechnology, such as blood and urine. Instrument development is extremely difficult and varied.
The flowmeters required for scientific experiments are not only numerous, but also extremely versatile. According to statistics, a large part of the flowmeters are used for scientific research. They are not mass-produced and are sold in the market. Many scientific research institutions and large enterprises have set up special teams to develop special flowmeters.
Target flowmeter: It was applied to industrial flow measurement in the 1960s. It can measure the flow rate of gas, liquid and steam. It is mainly used to solve the flow measurement of high viscosity and low Reynolds number fluid. It has experienced pneumatic watch and electric power. At the two stages of development, the SST and SBL smart target flowmeters are based on the original strain gauge target flowmeter measurement principle, using the latest chip II-level capacitive force sensor as the measurement and sensitive transmission component. At the same time, it uses a modern digital intelligent processing technology to develop a new type of flow meter.
Vortex flowmeter: It is mainly used for flow measurement of industrial pipeline medium fluids, such as gas, liquid, vapor and other media. It is characterized by small pressure loss, large measuring range and high precision. It is almost unaffected by parameters such as fluid density, pressure, temperature and viscosity when measuring the volume flow rate. No moving mechanical parts, so the reliability is high and the maintenance is small. Instrument parameters can be stable for a long time. The instrument uses a piezoelectric stress sensor with high reliability and can work in the operating temperature range of -20 ° C ~ +250 ° C. There are analog standard signals and digital pulse signal outputs, which are easy to use with digital systems such as computers. It is a relatively advanced and ideal flow meter.
V-cone flowmeter: V-cone flowmeter is widely used in petrochemical, natural gas and other fields due to its simple structure, firmness, easy replication, strong versatility and low price. The V-cone flowmeter overcomes the standard orifice plate, venturi tube, nozzle and other throttling devices, such as easy wear, large pressure loss, small range (range ratio), high field installation conditions, and requirements for straight pipe lengths, etc. It accurately measures the flow of various fluids over a wide range of Reynolds numbers. Compared with common differential pressure flowmeter, STV series V-cone flowmeter has high precision, long-term precision, good repeatability, limited installation conditions, wear resistance, wide measuring range, suitable for dirty media and pressure loss. Small, long service life and so on. Can be widely used in various fields, suitable for measuring water, oil, a variety of liquids, steam, air, natural gas, gas, petroleum gas, organic gases, oil residues and so on.
Integrated orifice flowmeter: standard orifice plate and multi-parameter differential pressure transmitter (
Or differential pressure transmitter, temperature transmitter and pressure transmitter) is a high-range ratio differential pressure flow device that can measure the flow of gas, steam, liquid and natural gas. It is widely used in petroleum, chemical, metallurgy and electric power. Process control and measurement in areas such as heating and water supply.
Verabar Flowmeter: High-precision flow measurement for gases, liquids and vapors. Verabar is a differential pressure, rate-averaged flow sensor that measures flow through the differential pressure generated by the sensor in the fluid. Verabar reflects the true flow rate of the fluid with an accuracy of ± 1.0% and repeatability of ± 0.1%. The outstanding advantage of Verabar is that it outputs a very stable, pulse-free differential pressure signal.
The low-pressure holes of the power bar achieve the essential anti-blocking. Under normal circumstances, dust, sand and particles are concentrated in the back of the probe under the action of vortex force. This is why autumn leaves are always concentrated behind the leeward house. The other probes are taken in the vacuum area of the probe tail due to the low pressure tapping hole. Under the action of the vortex force, the low pressure tapping hole of the probe is quickly blocked by the impurities brought by the eddy current. Verabar's unique design allows the low pressure tapping holes to be located on the back side of the probe side, the fluid separation point and the front of the wake area. This design essentially prevents clogging and produces a very stable low voltage signal.
First of all, we must fully understand the advantages and disadvantages of various types of flowmeters. Secondly, we should fully understand the physical and chemical properties of the medium, and fully understand the process conditions and environment of the installation site. Finally, we must know the user's flow. The measurement accuracy requirement, considering whether the medium flow meets the flow range requirements of the flowmeter, whether the installation site meets the on-site installation requirements of the flowmeter, and also considers which conditions and factors will affect the metering of the flowmeter. Summary 1. Pay attention to product selection 2. Have good products 3. Be properly installed 4. Pay attention to daily maintenance 5. Regularly send inspections.
Huaheng Instrument, specializing in the development and manufacture of gas flow meters. We supply vortex flowmeters, orifice flowmeters, electromagnetic flowmeters and other gas flowmeters with stable performance and accurate measurement. Welcome to call us for advice.