Standard Gas Flow Meter Calibration – A Guarantee of Accuracy

The accuracy of the mass flow controller (MFC) is important to ensure the performance, quality, and efficiency of a flow meter.

If an instrument is not calibrated, its performance can decline as a result of sensor drift from the factory calibration. Such a drift can be caused by various things such as aging of electronics, physical change in the sensor, and dirt buildup, among others.

许多用户每年验证或重新校准MFC或流量计，以确保保持MFC读数的准确性。在某些行业中，政府法规，例如FDA，MACT或EPA命令或公司政策，要求保证流量计的准确性。

Although there are numerous ways to calibrate MFCs, the ideal method to ensure accuracy is a primary standard calibration.

Primary Standard = Precision Calibration

World-class levels of traceability and accuracy can only be obtained through primary standard gas flow calibration systems. The following aspects have to be considered in mass flow meter primary standard calibration:

1. Unlike laminar flow elements and other transfer or secondary standards that are calibrated against another instrument, primary standards are characterized by the basic quantities of distance and time. In addition, all national laboratories can verify primary standards.
2. 校准标准必须是NIST可追溯的标准精度，大于全尺度的1％
3. The NIST “rule of four” is followed by the most accurate primary standards. This means the accuracy of the gas flow primary standards must be four times that of the device under test. All calibration houses and factory calibrations must make this “rule of four” a basic requirement.
4. 流量计校准既是艺术，又是科学。亚博老虎机网登录必须寻求流量计校准或流量计制造的专业知识。最好的流量计校准可以在制造工厂而不是第三方校准房屋中获得，因为工厂将拥有仪表和流校准核心竞争力的工作知识。
5. Facilities (Figure 1) should have ISA 17025 & NAVLAP compliance and/or ISO 9001 certification

Figure 1.Calibration facility

Sierra’s SmartTrak Mass Flow

Sierra is among the few manufacturers that perform a thorough 10-point calibration across the full mass flow range. The company strictly follows the NIST “rule of four” and adheres to employing primary standards.

Sierra’s SmartTrak mass flow controlleris a great example of this. The controller’s NIST-traceable standard accuracy is better than 1% of full scale. The company offers even better accuracy, up to half a percent of full scale, upon request.

This information has been sourced, reviewed and adapted from materials provided by Sierra Instruments.

For more information on this source, please visit塞拉仪器。