Flow rate range variable type flow rate control apparatus

• US 8,418,714 B2
• Filed: 06/22/2006
• Issued: 04/16/2013
• Est. Priority Date: 06/27/2005
• Status: Active Grant

• Current Assignee: Fujikin Incorporated, National University Corporation Chiba University, Tokyo Electron Limited
• Original Assignee: Fujikin Incorporated, National University Corporation Chiba University, Tokyo Electron Limited
• Inventors: Ohmi, Tadahiro, Saito, Masahito, Shimazu, Tsuyoshi, Miura, Kazuyuki, Nishino, Kouji, Nagase, Masaaki, Sugita, Katsuyuki, Hirata, Kaoru, Dohi, Ryousuke, Hirose, Takashi, Shinohara, Tsutomu, Ikeda, Nobukazu, Imai, Tomokazu, Yoshida, Toshihide, Tanaka, Hisashi, Hino, Shoichi
• Primary Examiner(s): Fox, John
• Assistant Examiner(s): FAULB, SETH J
• Application Number:
  US11/913,277
• Publication Number:
  US 20100139775A1
• Time in Patent Office: 2,490 Days
• Field of Search: 137/486, 137/487, 137/599.07, 137/599.06, 137/599.01, 137/625.3
• US Class Current: 137/486
• CPC Class Codes: G01F 1/363 with electrical or electro-mechanical indication G01F1/37 and G01F1/38 take precedence
• CPC Class Codes: G01F 1/6842 with means for influencing the fluid flow
• CPC Class Codes: G01F 1/6847 where sensing or heating elements are not disturbing the fluid flow, e.g. elements mounted outside the flow duct
• CPC Class Codes: G01F 5/005 by measuring pressure or differential pressure, created by the use of flow constriction
• CPC Class Codes: G01F 7/005 by measuring pressure or differential pressure, created by the use of flow constriction
• CPC Class Codes: G05D 23/1927 using a plurality of sensors G05D23/1902, G05D23/1917, and G05D23/1919 take precedence
• CPC Class Codes: G05D 7/0635 by action on throttling means G05D7/0688, G05D7/0694 take precedence
• CPC Class Codes: G05D 7/0641 using a plurality of throttling means G05D7/067 takes precedence
• CPC Class Codes: G05D 7/0647 the plurality of throttling means being arranged in series
• CPC Class Codes: Y10T 137/0379 By fluid pressure
• CPC Class Codes: Y10T 137/7759 Responsive to change in rate of fluid flow
• CPC Class Codes: Y10T 137/776 Control by pressures across flow line valve
• CPC Class Codes: Y10T 137/8593 Systems
• CPC Class Codes: Y10T 137/86734 With metering feature
• CPC Class Codes: Y10T 137/86815 Multiple inlet with single outlet
• CPC Class Codes: Y10T 137/87265 Dividing into parallel flow paths with recombining
• CPC Class Codes: Y10T 137/87314 Electromagnetic or electric control [e.g., digital control, bistable electro control, etc.]
• CPC Class Codes: Y10T 137/8741 With common operator
• CPC Class Codes: Y10T 137/87499 Fluid actuated or retarded
• CPC Class Codes: Y10T 137/87684 Valve in each inlet

Abstract

A pressure type flow rate control apparatus is provided wherein flow rate of fluid passing through an orifice is computed as Qc=KP1 (where K is a proportionality constant) or as Qc=KP2^m(P1−P2)ⁿ (where K is a proportionality constant, m and n constants) by using orifice upstream side pressure P1 and/or orifice downstream side pressure P2. A fluid passage between the downstream side of a control valve and a fluid supply pipe of the pressure type flow rate control apparatus comprises at least 2 fluid passages in parallel, and orifices having different flow rate characteristics are provided for each of these fluid passages, wherein fluid in a small flow quantity area flows to one orifice for flow control of fluid in the small flow quantity area, while fluid in a large flow quantity area flows to the other orifice for flow control of fluid in the large flow quantity area.

Claims

1. A flow rate range variable type flow rate control apparatus comprising:

(a) a pressure type flow rate control apparatus that operates to control flow rate Qc of fluid passing through an orifice according to the relationship Qc=KP1 when a critical condition between P1 and P2 is present, where K is a proportionality constant, or the pressure type flow rate control apparatus operates to control the flow rate Qc through the orifice according to the relationship Qc=KP2^m(P1−

P2)ⁿ when the critical condition between P1 and P2 is not present, where K is the proportionality constant, and m and n constants, wherein P1 is an orifice upstream side pressure and P2 is an orifice downstream side pressure; and

(b) a first fluid passage disposed between a downstream side of a control valve and a fluid supply pipe of the pressure type flow rate control apparatus, wherein the first fluid passage comprises two second fluid passages arranged in parallel, wherein

the two second fluid passages are provided with a plurality of orifices having different flow rate characteristics, wherein the plurality of orifices include a first orifice and a second orifice, wherein fluid flowing in a small flow quantity range is made to flow to the first orifice for effecting flow control of fluid flowing in the small flow quantity range, while fluid flowing in a large flow quantity range is made to flow to the second orifice for effecting flow control of fluid flowing in the large flow quantity range,

wherein the second orifice controls large flow quantity and the first orifice controls small flow quantity, wherein a control range of fluid flow rate is switched either to the small flow quantity range or to the large flow quantity range by operating a switching valve installed on the one of the two second fluid passages in which the second orifice for controlling large flow quantity is disposed,

and when controlling large flow quantity, a total flow quantity supplied to the fluid supply pipe of the pressure type flow rate control apparatus comprises the large flow quantity controlled by the second orifice and the small flow quantity controlled by the first orifice.

2. A flow rate range variable type flow rate control apparatus as claimed in claim 1, wherein fluid flowing through the first orifice of the pressure type flow rate control apparatus is fluid under the critical condition.

3. A method of controlling fluid flow of a fluid supply system comprising the steps of:

(a) providing a fluid supply system comprising a flow rate range variable type flow rate control apparatus comprising

i. a first fluid passage for small flow quantity;

ii. a second fluid passage for large flow quantity; and

iii. switching means of switching fluid for flowing in a large flow quantity range and fluid for flowing in a small flow quantity range so that the first fluid passage and the second fluid passage are operably connected to a flow rate detection part of the flow rate control apparatus, wherein the switching means operates in a first mode to make fluid flowing in the small flow quantity range flow to the flow detection part through the first fluid passage for small flow quantity and to switch a detection level of a flow rate control part to a first detection level suitable for detection of fluid flowing in the small flow quantity range and the switching means operates in a second mode to make fluid flowing in the large flow quantity range flow to the flow detection part through the second fluid passage for large flow quantity and to switch the detection level of the flow rate detection control part to a second detection level suitable for detection of fluid flowing in the large flow quantity range; and

(b) controlling a flow rate of fluid in the fluid supply system by operating the switching means in the first mode so fluid flows through a first orifice at a flow rate in the small flow quantity range and by operating the switching means in the second mode so fluid flows through a second orifice at a flow rate in the large quantity flow range, wherein the second orifice controls large flow quantity and the first orifice controls small flow quantity, wherein a control range of fluid flow rate is switched either to the small flow quantity range or to the large flow quantity range by operating the switching means installed on the second fluid passage in which the second orifice for controlling large flow quantity is disposed,

and when controlling large flow quantity, a total flow quantity supplied to a fluid supply pipe of a pressure type flow rate control apparatus of the flow rate range variable type flow rate control apparatus comprises the large flow quantity controlled by the second orifice and the small flow quantity controlled by the first orifice.

4. A method as claimed in claim 3, wherein fluid flowing through the first orifice of the pressure type flow rate control apparatus is fluid under a critical condition.