| 第一次使用孔板流量计的正确方法？ |
| 信息来源： 流量变送器厂家 | 2019-04-09 点击量： 3924 |
第一次使用孔板流量计的正确方法？西安华恒仪表制造有限公司为您讲解：孔板流量计一般管道式充满液体的，液体经过节流装置时，流束将在节流装置会局部收缩，增加流速，压力低，所以节流件前后会减低压力，就是压差，介质流动的流量越大，压差就越大，一般气体孔板流量计通过测量差压计算出流体的速度。
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.
安装前节流件用的直管最好是光滑的，如果不光滑，流量系数就要用到粗糙度修正系数来计算。
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.
节流件前后的直管段一定要直；直管段一定要圆的，而且对节流件前2D范围，有一定的圆度指标；节流件前后直管段长度要保留足，这段足够长的直管段和节流件前的局部阻力件形式有关和直径比
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.
节流装置设计计算时，孔板外径与环室配合处的间隙留得足够大是假定孔板和环室温度相同，但实际上不可能相同，孔板被环室包围着，而且有高温流体为其提供热量，所以温度高，得到充分膨胀。
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.
而环室内圆与流体接触，但外圆与大气接触，加上外部环境温度等因素，使其温度下降得很低，从而导致预留的间隙不够用，引起孔板变形。
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.
孔板流量计按国标规定进行设计、制造和检定的标准孔板无需实流标定，精度高、结构简单、制造成本低，但压力损失在所有标准节流装置中最大，不适用于要求压力损失小的情况，标准孔板广泛用于石油、化工、冶金、电力等行业。
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.
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