Methods, systems, and apparatus for mass flow verification based on choked flow

Mass flow verification systems and apparatus may verify mass flow rates of mass flow controllers (MFCs) based on choked flow principles. These systems and apparatus may include a plurality of differently-sized flow restrictors coupled in parallel. A wide range of flow rates may be verified via selection of a flow path through one of the flow restrictors based on an MFC's set point. Mass flow ratesmay be determined via pressure and temperature measurements upstream of the flow restrictors under choked flow conditions. Methods of verifying a mass flow rate based on choked flow principles are also provided, as well as other aspects. 质量流验证系统与设备可依据扼流原理而验证质量流控制器(MFC)的质量流速率。这些系统与设备可以包括并联耦接的多个不同尺寸的流量限制器。可以经由依据MFC的设定点而选择通过流量限制器中的个的流动路径以验证各种流动速率。可以经由在扼流条件下的流量限制器的上游的压力与温度测量而确定质量流速率。也提供依据扼流原理验证质量流速率的方法，以及其他态样。