FLOW RATE RANGE VARIABLE TYPE FLOW RATE CONTROL APPARATUS

• US 20100139775A1
• Filed: 06/22/2006
• Published: 06/10/2010
• 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: Hirose, Takashi, Miura, Kazuyuki, Saito, Masahito, Tanaka, Hisashi, Hino, Shoichi, Yoshida, Toshihide, Shimazu, Tsuyoshi, Ohmi, Tadahiro, Imai, Tomokazu, Shinohara, Tsutomu, Sugita, Katsuyuki, Ikeda, Nobukazu, Nishino, Kouji, Dohi, Ryousuke, Nagase, Masaaki, Hirata, Kaoru
• Granted Patent: US 8,418,714 B2
• Time in Patent Office: Days
• US Class Current: 137/12
• 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 control device enabling a reduction in size and an installation cost by accurately controlling the flow of a fluid in a wide flow range. Specifically, the flow of the fluid flowing in an orifice (8) is calculated as Qc=KP₁ (K is a proportionality factor) or Qc=KP₂^m(P₁−P₂)ⁿ (K is a proportionality factor and m and n are constants) by using a pressure P₁ on the upstream side of the orifice and a pressure P₂ on the downstream side of the orifice. A fluid passage between the downstream side of the control valve of the flow control device and a fluid feed pipe is formed of at least two or more fluid passages positioned parallel with each other. Orifices with different fluid flow characteristics are interposed in the fluid passages positioned parallel with each other. For the control of the fluid in a small flow area, the fluid in the small flow area is allowed to flow to one orifice. For the control of the flow in the large flow area, the fluid in the large flow area is allowed to flow to the other orifice by switching the fluid passages.

Claims

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

a first fluid passage for small flow quantity;

a second fluid passage for large flow quantity; and

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 for 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 for 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.

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

a pressure type flow rate control apparatus wherein flow rate of fluid passing through an orifice Qc=KP1 where K is a proportionality constant, or is Qc=KP2^m(P1−

P2)ⁿ where K is a proportionality constant, and m and n constants, wherein P1 is an orifice upstream side pressure and P2 is an orifice downstream side pressure;

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 at least two second fluid passages in parallel; and

the 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.

3. A flow rate range variable type flow rate control apparatus as claimed in claim 2, wherein the number of second fluid passages arranged in parallel is two, and 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 second fluid passage in which the second orifice for controlling large flow quantity is disposed.

4. A flow rate range variable type flow rate control apparatus as claimed in claim 2, wherein the plurality of orifices include three different orifices, and the three different orifices include the second orifice for large flow quantity, a third orifice for medium flow quantity and the first orifice for small flow quantity, and wherein the flow rate range variable type flow rate control apparatus further comprises a first switching valve and a second switching valve, wherein the first switching valve, the second switching valve and the orifice for large flow quantity are provided in series on one of the second fluid passages while the orifice for small flow quantity and the orifice for medium flow quantity are provided on the other one of the second fluid passages, and a fluid passage communicating between the first switching valve and the second switching valve and a fluid passage communicating between the orifice for small flow quantity and the orifice for medium flow quantity are in communication with each other.

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

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

(a) a thermal type mass flow rate control apparatus comprising

i. a flow rate control valve connected to a first fluid passage;

ii. a laminar flow element device part disposed on the first fluid passage; and

iii. a flow rate sensor part, wherein temperature changes in proportion to a mass flow rate of fluid are detected at the flow rate sensor part, and a fluid with a predetermined set flow rate is made to flow out by opening or closing the flow rate control valve based on detected temperature of fluid flowing in the first fluid passage; and

(b) a second fluid passage to the flow rate control valve that comprises at least two third fluid passages arranged in parallel, wherein each third fluid passage is provided with a laminar flow element and a flow rate sensor, wherein each laminar flow element has a different coarseness from the other, and fluid flowing in a small flow quantity range is made to flow to one laminar flow element that controls flow rate of fluid flowing in the small flow quantity range while fluid flowing in the large flow quantity range is made to flow to the other laminar flow element that controls flow rate control of fluid flowing in the large flow quantity range.

7. A flow rate range variable type flow rate control apparatus as claimed in claim 6, wherein the number of third fluid passages in parallel is two, and the corresponding two laminar flow elements include a coarse laminar flow element for large flow quantity and a fine laminar flow element for small flow quantity, and 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 switching valves respectively provided on each third fluid passage.

8. 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. 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 at a flow rate in the small flow quantity range and by operating the switching means in the second mode so fluid flows at a flow rate in the large quantity flow range.

9. A method as claimed in claim 8, wherein fluid flowing through an orifice of the pressure type flow rate control apparatus is fluid under a critical condition.