|信息来源： 华恒 | [ 2019-04-09] 点击量： 250|
The correct way to use orifice flowmeter for the first time?Xi'an Huaheng Instrument Manufacturing Co.,Ltd.will explain to you:orifice flowmeter is usually filled with liquid in pipeline.When liquid passes through the throttle device,the flow beam will shrink locally,increase the flow rate,and the pressure is low.Therefore,the pressure difference will be reduced before and after the throttle piece.The larger the flow rate of medium,the larger the pressure difference will be.The general orifice flowmeter will measure the differential pressure gauge by measuring the differential pressure gauge.Calculate the velocity of the fluid.
The straight pipe used for throttling before installation should be smooth.If it is not smooth,the flow coefficient should be calculated by roughness correction coefficient.
The straight pipe section must be straight before and after the throttle piece;the straight pipe section must be round,and have a certain roundness index for the range of 2D before the throttle piece;the length of the straight pipe section before and after the throttle piece should be kept enough,and the form and diameter ratio of the long straight pipe section and the local resistance parts before the throttle piece are relevant and diameter ratio.
When designing and calculating the throttling device,the clearance between the orifice plate outer diameter and the ring chamber is large enough to assume that the temperature of the orifice plate and the ring chamber is the same,but in fact it is impossible to be the same.The orifice plate is surrounded by the ring chamber,and there is high temperature fluid to provide heat for it,so the temperature is high and it is fully expanded.
The inner circle of the ring contacts with the fluid,but the outer circle contacts with the atmosphere,and the external environment temperature and other factors make the temperature drop very low,resulting in insufficient reserved clearance,causing the orifice plate to deform.
The orifice plate flowmeter designed,manufactured and calibrated according to the national standard does not need real-flow calibration.It has high accuracy,simple structure and low manufacturing cost.However,the pressure loss is the largest in all standard throttling devices,and it is not suitable for situations requiring low pressure loss.The standard orifice plate is widely used in petroleum,chemical,metallurgical,power and other industries.