| 压力表的选择都有什么形式 |
| 信息来源： 压力变送器 | 2019-04-24 点击量： 6262 |
压力表的选择都有什么形式？西安华恒仪表介绍：根据产品工艺要求正确选用仪表类型是保证仪表正常工作及安全生产的重要前提。通常选择压力表类型时要考虑以下三方面的要求：
What are the forms of pressure gauge selection?Introduction of Xi'an Huaheng Instrument:Correct selection of instrument types according to product process requirements is an important prerequisite for ensuring normal operation and safe production of instruments.Usually when choosing the type of pressure gauge,the following three requirements should be considered:
(1)根据工业生产中产品工艺的要求选择。例如是否需要远传、自动记录或报警；
(2)根据被测介质的物理化学性能(诸如腐蚀性、温度高低、粘度大小、脏污程度、易燃易爆性能等)是否对测量仪表提出特殊要求选择；
(3)根据现场环境条件(诸如高温、电磁场、振动及现场安装条件等)对压力表类型有否特殊要求等选择。
(1)Selection according to the requirements of product process in industrial production.For example,whether remote transmission,automatic recording or alarm are needed;
(2)According to the physical and chemical properties(such as corrosiveness,temperature,viscosity,dirty degree,inflammable and explosive properties)of the medium under test,the special requirements for the measuring instruments are selected.
(3)According to the site environmental conditions(such as high temperature,electromagnetic field,vibration and site installation conditions),whether there are special requirements for pressure gauge types and so on.
1、压力表的测量范围的确定:为了合理、经济使用仪表，仪表的量程不能选得太大，但为了保证测量精度，一般被测压力的最小值不低于仪表满量程的1／3为宜。同时为了延长弹性元件的使用寿命，避免弹性元件因长期受力过大而永久变形，压力计的上限值应该高于被测量的最大值(量程的1／2~1／3)，留有余量。
1.Determining the measuring range of pressure gauge:In order to use the instrument reasonably and economically,the measuring range of the instrument can not be too large,but in order to ensure the measuring accuracy,it is generally advisable that the minimum value of the measured pressure is not less than one third of the full measuring range of the instrument.At the same time,in order to prolong the service life of the elastic element and avoid the permanent deformation of the elastic element due to long-term excessive force,the upper limit value of the pressure gauge should be higher than the maximum value of the measured value(1/2-1/3 of the range),leaving a margin.
2、压力表精度的选取:压力表精度是根据工艺生产上所允许的最大测量误差来确定的。不能认为选用的仪表精度越高越好，应在满足工艺要求的前提下，尽可能选用精度较低、价廉耐用的仪表。
2.Selection of pressure gauge accuracy:pressure gauge accuracy is determined according to the maximum measurement error allowed in process production.It can't be considered that the higher the accuracy of the selected instrument,the better.On the premise of meeting the technological requirements,the instrument with lower accuracy and low cost and durability should be selected as far as possible.
仪表类型选择实例：某台压缩机的出口压力范围为25～28MPa，测量绝对误差不得大于1MPa。工艺上要求就地观察，并能高低限报警，试正确选用一台压力表，指出型号、精度与测量范围。要求条件为：被测脉动压力25～28MPa，测量绝对误差≤1MPa，就地观察、高低限报警。
Examples of instrument type selection:The outlet pressure of a compressor ranges from 25 to 28 MPa,and the absolute error of measurement should not be greater than 1 MPa.The technology requires on-site observation and alarm at high and low limits.A pressure gauge should be selected correctly and the type,accuracy and measurement range should be pointed out.Requirements are:the measured fluctuating pressure is 25-28 MPa,the absolute error of measurement is less than 1 MPa,in-situ observation,high and low limit alarm.
仪表选择时考虑脉动压力对仪表寿命影响很大，故选择仪表的上限值为：P1=Pmax*2=28*2=56MPa若选压力表的测量范围为0～60MPa，则：25MPa／60MPa>l／3，被测压力的最小值不低于满量程的1／3，下限值也符合要求。另外，根据测量误差的要求，可算得对仪表允许误差的要求为：1／60*100％=1．67％，故选精度等级为1．5级的仪表，可以满足误差要求。
When choosing the instrument,the fluctuating pressure has a great influence on the life of the instrument.Therefore,the upper limit value of the instrument is:P1=Pmax*2=28*2=56MPa.If the measuring range of the selected pressure gauge is 0-60MPa,the minimum value of the measured pressure is not less than 1/3 of the full range,and the lower limit value also meets the requirements.In addition,according to the requirement of measurement error,it can be calculated that the allowable error of the instrument is 1/60*100%=1.67%.Therefore,the instrument of 1.5 precision level can meet the error requirement.
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