FLOW RATE RANGE VARIABLE TYPE FLOW RATE CONTROL APPARATUS
First Claim
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.
1 Assignment
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Accused Products
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=KP2m(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.
44 Citations
9 Claims
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1. A flow rate range variable type flow rate control apparatus comprising:
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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.
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2. A flow rate range variable type flow rate control apparatus comprising:
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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=KP2m(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. - View Dependent Claims (3, 4, 5)
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6. A flow rate range variable type flow rate control apparatus comprising:
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(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. - View Dependent Claims (7)
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8. A method of controlling fluid flow of a fluid supply system comprising the steps of:
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(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. - View Dependent Claims (9)
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Specification