| 怎么处理孔板流量计在应用中常见的问题 |
| 信息来源： 液位变送器厂家 | 2019-04-10 点击量： 4769 |
怎么处理孔板流量计在应用中常见的问题？在应用生活中总会有很多的不确定因素问题，孔板流量计是广泛应用于石油、化工、冶金、电力、供热、供水等领域的过程控制和测量的仪器。在使用过程中孔板流量计一般会出现哪些问题呢？
How to deal with the common problems in the application of orifice flowmeter?There are always many uncertainties in the application life.Orifice plate flowmeter is a process control and measurement instrument widely used in petroleum,chemical industry,metallurgy,electric power,heating,water supply and other fields.What are the problems of orifice flowmeter in use?
孔板流量计一般容易受被测流体特性、仪表性能安装及环境的影响。
Orifice plate flowmeters are generally vulnerable to the influence of measured fluid characteristics,instrument performance installation and environment.
由于天然气本身的性质，会随着外界环境温度的变化而发生复杂的变化，从而影响流量计的测量精度。对于天然气的测量，必须首先确定天然气的工作温度和压力。低密度气体对某些测量方法呈现困难，此时就要改变所选择的测量方法，或者作温度和(或)压力修正，以保证测量准确准确度。
Because of the nature of natural gas itself,complex changes will occur with the change of ambient temperature,thus affecting the measurement accuracy of flowmeters.For the measurement of natural gas,the working temperature and pressure of natural gas must be determined first.Low density gas is difficult for some measurement methods,so it is necessary to change the selected measurement methods,or make temperature and/or pressure correction to ensure the accuracy of measurement.
孔板流量计本身也会引起的误差，如孔板入口直角锐利度、管径尺寸与计算不符、孔板厚度误差、节流件附件产生台阶、偏心，孔板上游端面平度，环室尺寸产生台阶、偏心;取压位置，焊接、焊缝突出，取压孔加工不规范或堵塞，节流件不同轴度等等。这些因素都有可能影响孔板的重复性，影响测量精度。若仪表输出特性是非线性的，则这种影响更为突出。
The orifice flowmeter itself can also cause errors,such as orifice plate entrance right angle sharpness,diameter size and calculation inconsistency,orifice plate thickness error,orifice accessories Produce step,eccentricity,orifice plate upstream end flatness,ring chamber size produce step,eccentricity;pressure taking position,welding,welding seam prominent,pressure taking hole processing is not standardized or blocked,throttle parts of different axes and so on.These factors may affect the repeatability of orifice plate and the measurement accuracy.If the output characteristic of the instrument is non-linear,the influence will be more prominent.
管线布置的偏离造成的安装误差是普遍性的，其产生的主要原因是现场不能满足直管段要求的长度。虽然孔板流量计安装能正常使用了，但因所使用环境条件与预期的情况发生了改变，使仪表的一些性能参数和硬件方面也随之发生了改变，从而会改变流量计测量结果。
The installation error caused by the deviation of pipeline layout is universal,and the main reason is that the site can not meet the requirements of the length of straight pipeline section.Although orifice flowmeter installation can be used normally,some performance parameters and hardware aspects of the instrument have also changed due to the changes of the environment conditions and expectations,which will change the measurement results of the flowmeter.
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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