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[2017]温度自动控制仪表电伴热保温不当引起的故障现象

发布于:2018-01-02 16:14来源:J9九游会AG电伴热带 作者:电伴热带厂家点击:

当电(dian)伴热温(wen)度过(guo)高(gao).超过(guo)蒸发罐正常工况下水的沸(fei)点(dian)时,就会出(chu)现上(shang)文(wen)所述在变(bian)送器负压(ya)管中形(xing)成气/液(ye)两相的现象,引起(qi)变(bian)送器输出(chu)信号振荡,液(ye)位(wei)显示(shi)值(zhi)剧烈波动(dong),自动(dong)状态(tai)下,调节阀也跟着(zhe)来(lai)回开关,最(zui)终因冷凝水被蒸发而(er)使(shi)液(ye)位(wei)示(shi)值(zhi)要比真(zhen)实(shi)液(ye)位(wei)高(gao)。

而(er)(er)当(dang)没有伴热或(huo)伴热效果不(bu)佳(jia).负压(ya)(ya)(ya)管(guan)出(chu)现(xian)冻堵时.因(yin)(yin)冷凝水(shui)结冰而(er)(er)体积膨胀(zhang).在变(bian)送(song)器(qi)负压(ya)(ya)(ya)侧产生(sheng)的(de)(de)压(ya)(ya)(ya)力迅速加大(da).从而(er)(er)抵(di)消(xiao)或(huo)远高于(yu)变(bian)送(song)器(qi)正压(ya)(ya)(ya)侧罐(guan)内真(zhen)实(shi)(shi)液(ye)(ye)(ye)(ye)(ye)(ye)位(wei)的(de)(de)压(ya)(ya)(ya)力.最终使得液(ye)(ye)(ye)(ye)(ye)(ye)位(wei)变(bian)送(song)器(qi)输(shu)出(chu)减小至零(ling)点以下,液(ye)(ye)(ye)(ye)(ye)(ye)位(wei)显示(shi)值从正常示(shi)值迅速下降为零(ling)。而(er)(er)此时如果液(ye)(ye)(ye)(ye)(ye)(ye)位(wei)控(kong)制(zhi)处于(yu)自动状态(tai)下时,因(yin)(yin)液(ye)(ye)(ye)(ye)(ye)(ye)位(wei)设(she)定(ding)的(de)(de)给(ji)定(ding)值与液(ye)(ye)(ye)(ye)(ye)(ye)位(wei)测(ce)(ce)(ce)量值偏差增大(da),控(kong)制(zhi)系(xi)统(tong)迅速将调节阀开到(dao)最大(da)进(jin)(jin)行(xing)(xing)加料(liao).使真(zhen)实(shi)(shi)液(ye)(ye)(ye)(ye)(ye)(ye)位(wei)不(bu)断上升.超过(guo)工艺允许的(de)(de)最高液(ye)(ye)(ye)(ye)(ye)(ye)位(wei).而(er)(er)此时DCS操作站上的(de)(de)液(ye)(ye)(ye)(ye)(ye)(ye)位(wei)示(shi)值还保持在零(ling)。另(ling)外,对(dui)液(ye)(ye)(ye)(ye)(ye)(ye)位(wei)变(bian)送(song)器(qi)正压(ya)(ya)(ya)侧接VI处及负压(ya)(ya)(ya)侧负压(ya)(ya)(ya)管(guan)取(qu)压(ya)(ya)(ya)口(kou)进(jin)(jin)行(xing)(xing)冲洗(xi)的(de)(de)冲洗(xi)水(shui)支管(guan)也(ye)需(xu)进(jin)(jin)行(xing)(xing)良(liang)好的(de)(de)伴热.这些冲洗(xi)水(shui)管(guan)一旦冻堵.则有可能(neng)导致变(bian)送(song)器(qi)测(ce)(ce)(ce)量膜片出(chu)现(xian)结垢(gou)、负压(ya)(ya)(ya)管(guan)取(qu)压(ya)(ya)(ya)口(kou)堵塞,同样会使液(ye)(ye)(ye)(ye)(ye)(ye)位(wei)测(ce)(ce)(ce)量出(chu)现(xian)故障。

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