Mass flow controller (MFC) devices capable of self-verification and methods of providing for self-verifying mass flow control are provided. An MFC includes a chamber configured to receive a fluid, an upstream valve disposed upstream of the chamber, and a downstream control valve disposed downstream of the chamber. The MFC further includes a pressure drop element disposed downstream of the downstream control valve and first and second pressure sensors. A controller of the MFC is configured to control actuation of the downstream control valve by toggling between flow-based feedback control and pressure-based feedback control. In flow-based feedback control, a flow is monitored based on a rate of decay of pressure in the chamber as detected by the first pressure sensor upon closure of the upstream control valve. In pressure-based feedback control, a pressure upstream of the pressure drop element, as detected by the second pressure sensor, is monitored.

A flow meter (100) for measuring the flow rate of a fluid characterized by comprising a casing (1) having a first end (101) into which the fluid enters and a second end (102) from which the fluid exits, and within which a first duct (11) for receiving the fluid is present when it is at low flow rates; a measuring element (2) arranged internally to the first duct (11) for measuring the flow within the first duct (11);
said flow meter (100) being characterized by also comprising: a second duct (12), placed inside the casing (1), for receiving the fluid at high flow rates a closing element (3) which, when the flow rate exceeds an opening threshold, allows the fluid to flow into the second duct (12) an elastic element (4), connected to the closing element (3), for moving the closing element (3) from a closing configuration, in which the flow rate does not exceed the opening threshold, not overcoming the resistance of the elastic element (4) and the closing element (3) closes the second duct (12), to an opening configuration in which the flow rate exceeds the opening threshold, overcoming the resistance of the elastic element (4), and the closing element (3) opens the second duct (12).