的主要测量元件为一根垂直安装的下小上大锥形玻璃管和在内可上下移动的浮子。 The main measuring element of the glass rotor flowmeter is a vertically mounted lower and upper conical glass tube and a float that can move up and down inside. When the fluid passes through the conical glass tube from bottom to top, a pressure difference occurs between the upper and lower parts of the float, and the float rises under the effect of this differential pressure. When this rising force, the buoyancy and viscous lift force of the float are equal to the gravity of the float, the float is in an equilibrium position. Therefore, there is a certain proportional relationship between the flow rate of the fluid flowing through the glass rotor flowmeter and the rising height of the float, that is, the flow area of the glass rotor flowmeter.
Glass rotor flowmeter is mainly used in chemical, petroleum, light industry, medicine, fertilizer, chemical fiber, food, dyes, environmental protection and scientific research and other departments to measure the single-phase non-pulsating (liquid or gas) fluid flow. Anti-corrosive glass rotor flowmeter is mainly used to detect the flow of corrosive liquids and gaseous media, such as strong acids (except hydrofluoric acid), strong bases, oxidants, strong oxidizing acids, organic solvents and other corrosive gases or liquids Flow detection of media
的选用1． Selection of glass rotor flowmeter The object of measurement. That is to measure the type of medium, pressure, and chemical properties. For liquid and gaseous media, for corrosive media, a corrosion-resistant flowmeter should be selected.
2. The performance of the flow meter itself. After the above conditions are determined, generally speaking, if there is no major change in price, the needle valve is preferred to be placed on the upper part of the flowmeter; those with larger flow holes are directly flow-scaled; simple structures; smaller external dimensions, etc . If it is a small flow range, you can use the ball float type, because it is stable during measurement, not easy to accumulate dust, high accuracy, and good interchangeability. 3． Select based on price. Generally speaking, high accuracy and high price. To select the instrument accuracy level according to the measurement purpose, if only the measurement medium throughput is controlled, and after trial operation adjustment, the throughput must always be stabilized in the future, then the accuracy is secondary
安装和使用说明如何正确选用玻璃转子流量计玻璃转子流量计是一种使用简单、读数方便、用途十分广泛的瞬时流量测量仪表。 Glass rotor flowmeter installation and use instructions how to properly choose glass rotor flowmeter glass rotor flowmeter is a kind of instant flow measurement instrument that is simple to use, convenient to read, and widely used. In the field of environmental protection equipment and instruments, the amount is more than 30,000 units / year. Therefore, it is extremely important to choose and use this instrument. First, the type of glass to flowmeter and the selection of glass rotor flowmeter can be divided into: ordinary type, ribbed vascular type, micro flow and small outline type, corrosion resistance type, laboratory type, Eight series of insulation type, alarm type and high pressure resistance type. According to the instrument series spectrum developed by the country, no matter which series includes a maximum of 12 calibers from 1mm to 100mm, the measurable flow range is: liquid (water) 0.1ml / min ～ 40m3 / hour, gas (Air) 1ml / min ~ 1000m3 / hour. The glass rotor flowmeter used for environmental protection instruments generally has a diameter of no more than 10 mm, and the measured flow belongs to a small flow range. The selection of glass rotor flowmeter can be considered from the following aspects. 1. The object of measurement. That is to measure the type of medium, pressure, and chemical properties. For liquid and gaseous media, for corrosive media, a corrosion-resistant flowmeter should be selected. 2. The performance of the flow meter itself. After the above conditions are determined, generally speaking, if there is no major change in price, the needle valve is preferred to be placed on the upper part of the flowmeter; those with larger flow holes are directly flow-scaled; simple structures; smaller external dimensions, etc . If it is a small flow range, you can use the ball float type, because it is stable during measurement, not easy to accumulate dust, high accuracy, and good interchangeability. 3． Select based on price. Generally speaking, high accuracy and high price. To select the accuracy level of the instrument according to the measurement purpose, if you only need to control the throughput of the measurement medium and adjust it after trial operation, you must always stabilize the throughput in the future, then the accuracy is secondary. 4． When the fluid flows through the cone from bottom to top, the lift force S generated by the fluid kinetic energy on the float and the buoyancy A of the fluid rise the float. When the sum of the lift force S and the buoyancy A is equal to the float's own gravity G, the float is in equilibrium and stabilized At a height position, the scale on the cone indicates the flow rate of the fluid. Second, the scale correction of the glass rotor meteorometer The scale of the glass rotor flowmeter is calibrated by the manufacturer under the conditions of the factory using water and dry air that are close to ideal fluids. However, there are two situations where the scale value of the flowmeter cannot be used directly: one is that the measurement medium is not water and air, and the other is that the medium is water and air, but its state (temperature, pressure) and scale The status is different. In this way, when using a flow meter, in order to obtain a correct measurement result, a problem arises that the scale value needs to be corrected. Therefore, solving the calibration of the glass rotor flowmeter is the key to using this instrument. Considering that environmental protection instruments use rotor flowmeters to measure the flow of gaseous media, only the density correction in gaseous media measurement is discussed below. Because the viscosity of the gaseous medium is small, the viscosity effect is omitted in the discussion. Practice has proved that this does not affect the accuracy after the correction. The following is the general expression of the flowmeter of the rotor flow meter (1) is a calculation formula that does not consider the influence of the viscosity of the medium. It is obvious from formula (1) that when the position height of a flowmeter float is determined, the measured medium density ρ is the only variable. If the measured medium density is different, the flow rate of the medium through the flowmeter is also different. Therefore, the scale correction is actually the flow correction. If two media with different densities ρ1 and ρ2 pass through the same rotor flowmeter respectively, if the floats are balanced on the same position, the basic formula for the conversion of the density of the rotor flowmeter can be obtained from the formula (1): , T2 are the two states of the same medium, which are respectively expressed by two parameters of pressure and temperature. It can be seen that, for the same gas medium, its density conversion can be completely converted into temperature and pressure conversion under different states. In this way, the calibration correction for measuring the flow rate of the same gas medium eventually becomes the temperature and pressure state correction (essentially, the density correction). Obviously, this is a correction method that is generally easy to achieve using a unit.