的刻度，是生产厂在本厂条件下用近于理想流体的水和干燥空气作介质标定得到的。 The calibration of the glass rotor flowmeter is obtained by the factory under the conditions of the factory using water and dry air close to the ideal fluid as the medium. 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 glass tube rotor flowmeter has a simple structure and a glass tube rotor flowmeter. It is easy to use and has the disadvantage of low pressure resistance and a greater risk of fragility of the glass tube; suitable for small diameters and low flow rates; low pressure loss. Also known as fixed displacement flowmeter, referred to as PD flowmeter, the flow meter is the highest accuracy type. The mechanical measuring element is used to continuously and continuously divide the fluid into a single known volume part, and the total volume of the fluid is measured according to the number of times the measuring chamber is repeatedly filled and discharged. Can be divided into elliptical gear flowmeter, scraper flowmeter, double rotor flowmeter, rotary piston flowmeter, reciprocating piston flowmeter, disc flowmeter, liquid-sealed drum flowmeter, wet gas meter and membrane gas meter, etc. . Glass tube rotor flowmeters are classified according to their measuring elements. They are often used for total measurement of expensive media (oil, natural gas, etc.). Glass tube rotor flowmeter, differential pressure flowmeter and float flowmeter are ranked as the three most used flowmeters.
的选用可从以下几个方面考虑。 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.
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 the bottom to the top, a pressure difference occurs between the upper and lower parts of the float, and the float rises under the action 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 height of the float, that is, the flow meter area of the glass rotor flowmeter. The position height of the float can be used as a flow measurement. 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 The flow detection of the medium is used to measure the instantaneous flow. The usual unit of measurement is cubic meters / hour, and there are liters / minute. Liquid and gas can be measured. It is mainly used in chemical, power plants, sewage treatment and other places.