# US 12,000,723 B2 · Method and apparatus for pressure based mass flow control > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,000,723 B2 - Document ID: US12000723B2 - Status: Granted - Kind: B2 - Application number: 17/651,751 - Filed: 2022-02-18 - Published: 2023-08-24 - Granted: 2024-06-04 - Earliest claimed: 2022-02-18 - Assignees: MKS Instruments, Inc. - Applicants: MKS Instruments, Inc. - Inventors: Junhua Ding - Web page: https://patentgrep.com/patent/US12000723B2 ## CPC - G01F 1/88: with differential-pressure measurement to determine the volume flow - G05D 7/0635: {by action on throttling means (G05D7/0688, G05D7/0694 take precedence)} - G01F 15/005: {Valves (valves in general F16K)} - G01F 15/002: {for gases} - G01F 15/003: {using electromagnetic, electric or electronic means (G01F15/002, G01F15/02 take precedence)} - G05D 7/00: Control of flow (level control G05D9/00; control of flow ratio G05D11/00) - G05D 16/028: {Controlling a pressure difference (control of flow G05D7/00)} - G01F: MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME - G05D: SYSTEMS FOR CONTROLLING OR REGULATING NON-ELECTRIC VARIABLES ## Abstract Mass flow controllers that can provide for improved bleeding time and can be manufactured with less complexity and cost are provided. A mass flow controller includes a body having a valve outlet bore defining a flow path and an adjustable valve configured to control flow of a gas through the flow path. A valve element includes an outlet orifice of the adjustable valve and is disposed within the bore. The mass flow controller further includes a pressure drop element disposed coaxially with the valve element within the bore. An upstream pressure sensor is configured to detect a pressure at a location in the flow path between the adjustable valve and the pressure drop element, and a controller is configured to determine a flow rate through the flow path based on pressure as detected by the upstream pressure sensor. ## Claims ### Claim 1 A mass flow controller, comprising: a body having a valve outlet bore defining a flow path; an adjustable valve configured to control flow of a gas through the flow path, a valve element comprising an outlet orifice of the adjustable valve, the valve element disposed within the bore; a pressure drop element disposed coaxially with the valve element within the bore; an upstream pressure sensor configured to detect a pressure at a location in the flow path between the adjustable valve and the pressure drop element; and a controller configured to determine a flow rate through the flow path based on pressure as detected by the upstream pressure sensor. ### Claim 2 (depends on 1) The mass flow controller of claim 1, wherein the pressure drop element is adjacent to the outlet orifice within the bore. ### Claim 3 (depends on 1) The mass flow controller of claim 1, wherein the pressure drop element is disposed at a minimum distance within the bore with respect to the outlet orifice. ### Claim 4 (depends on 1) The mass flow controller of claim 1, wherein a volume between the pressure drop element and the outlet orifice within the bore is less than about 0.05 cm3. ### Claim 5 (depends on 1) The mass flow controller of claim 1, wherein the bore is substantially perpendicular to a surface of the body at which the adjustable valve is mounted. ### Claim 6 (depends on 1) The mass flow controller of claim 1, wherein the body further defines a pressure measurement conduit extending from the location in the flow path between the adjustable valve and the pressure drop element to a surface of the body. ### Claim 7 (depends on 6) The mass flow controller of claim 6, wherein the pressure measurement conduit extends laterally from the bore to a surface of the body at which the upstream pressure sensor is mounted. ### Claim 8 (depends on 1) The mass flow controller of claim 1, further comprising a downstream pressure sensor configured to detect a pressure downstream of the pressure drop element, wherein the controller is further configured to determine the flow rate based on pressure as detected by the downstream pressure sensor. ### Claim 9 (depends on 1) The mass flow controller of claim 1, wherein the pressure drop element is a flow nozzle. ### Claim 10 (depends on 1) The mass flow controller of claim 1, wherein the pressure drop element is a laminar flow element. ### Claim 11 (depends on 1) The mass flow controller of claim 1, wherein the pressure drop element is a porous media flow restrictor. ### Claim 12 (depends on 1) The mass flow controller of claim 1, wherein the body further includes a controller inlet bore and a controller outlet bore, the valve outlet bore disposed generally transverse to at least one of the controller inlet and outlet bores. ### Claim 13 (depends on 1) The mass flow controller of claim 1, wherein a valve actuator of the adjustable valve drives a valve member in a direction coaxial with the valve outlet bore. ### Claim 14 A mass flow controller, comprising: a body defining a flow path; an adjustable control valve configured to provide for a controllable range of open states and configured to control flow of a gas through the flow path, the adjustable control valve comprising an outlet orifice and a pressure drop element disposed in the outlet orifice of the adjustable control valve; an upstream pressure sensor configured to detect pressure at a location in the adjustable control valve between an armature of the adjustable control valve and the pressure drop element; and a controller configured to determine a flow rate through the flow path based on pressure as detected by the upstream pressure sensor. ### Claim 15 (depends on 14) The mass flow controller of claim 14, wherein the outlet orifice of the valve comprises a body defining a pressure measurement conduit disposed upstream of the pressure drop element. ### Claim 16 (depends on 15) The mass flow controller of claim 15, wherein the body defining the flow path further defines a pressure measurement conduit in fluid communication with the pressure measurement conduit of the outlet orifice. ### Claim 17 (depends on 14) The mass flow controller of claim 14, further comprising a downstream pressure sensor configured to detect a pressure downstream of the pressure drop element, wherein the controller is further configured to determine the flow rate based on pressure as detected by the downstream pressure sensor. ### Claim 18 (depends on 14) The mass flow controller of claim 14, wherein the pressure drop element is a flow nozzle. ### Claim 19 (depends on 14) The mass flow controller of claim 14, wherein the pressure drop element is a laminar flow element. ### Claim 20 (depends on 14) The mass flow controller of claim 14, wherein the pressure drop element is a porous media flow restrictor. ### Claim 21 (depends on 14) The mass flow controller of claim 14, further comprising a retainer disposed within the outlet orifice and configured to retain the pressure drop element. ### Claim 22 (depends on 14) The mass flow controller of claim 14, wherein the body defining the flow path comprises a valve outlet bore, a valve element comprising the outlet orifice of the adjustable valve disposed within the valve outlet bore. ### Claim 23 (depends on 14) The mass flow controller of claim 14, wherein the body further includes a controller inlet bore and a controller outlet bore, the valve outlet bore disposed generally transverse to at least one of the controller inlet and outlet bores. ### Claim 24 (depends on 14) The mass flow controller of claim 14, wherein a linear valve actuator of the adjustable valve drives a valve member in a direction coaxial with the valve outlet bore.