Patent ID: 11940307
Assignee: MKS INSTRUMENTS, INC.
Field: Measurement (Instruments)
Classification: CPC G | IPC G

Claim 19:
20. A method of dividing a mass flow into secondary flows of desired ratios comprising:
receiving an inlet flow at an inlet;
dividing the inlet flow into secondary flow lines connected to the inlet, each secondary flow line including:
a flow path configured to carry a secondary flow with a secondary flow rate;
a pressure drop element in the flow path;
a valve upstream of the pressure drop element configured to control the secondary flow rate based upon a control signal;
a pressure sensor between the valve and the pressure drop element configured to provide a pressure signal representative of pressure at the pressure drop element; and
a differential pressure sensing element in communication with pressures upstream and downstream of the pressure drop element and configured to provide a differential pressure signal representative of differential pressure across the pressure drop element; and

determining, by a controller, the secondary flow rate of each secondary flow line based upon the pressure signal and the differential pressure signal; and
by the controller, generating and applying the control signal to each valve to obtain a desired ratio of secondary flow rate to total flow rate.