MASS FLOW VERIFIER WITH FLOW RESTRICTOR

摘要

A flow verifier for verifying measurement of a flow rate of a fluid by a device includes a flow restrictor that renders the flow rate verification substantially insensitive to elements upstream of the flow restrictor. The flow verifier includes a vessel that receives a flow of the fluid from the device, and a pressure sensor that measures pressure of the fluid within the vessel. An outlet valve regulates flow of the fluid out of the vessel. The flow restrictor is located adjacent to and upstream of the vessel, along a flow path of the fluid. The flow restrictor restricts the flow of the fluid so as to induce a shock in the flow path of the fluid, and sustains the shock during a time period sufficient to render the flow rate verification substantially insensitive to the elements upstream of the flow restrictor.