Fluid handling – Line condition change responsive valves – Thermal responsive
Patent
1980-10-03
1987-04-21
Cohan, Alan
Fluid handling
Line condition change responsive valves
Thermal responsive
137486, 1374875, G05D 706
Patent
active
046588558
ABSTRACT:
A mass flow controller is disclosed herein having a bridge with a pair of arms positioned in good heat transfer relation with a gas stream, the flow rate of which is to be controlled and energized by a constant current generator wherein a resistance difference due to differential cooling by the gas stream is sensed by a bridge amplifier. A linearization network receives a signal from the bridge amplifier and applies one or more correction factors to the bridge amplifier signal to yield a linearized signal having a substantially linear relation to the rate of flow of the gas stream. A comparator receives the linearized signal and a user selectable set point signal and produces a comparator output signal which is sensed by a servoamplifier. The servoamplifier controls a valve which meters the rate of flow of the gas stream.
REFERENCES:
patent: 3372590 (1968-03-01), Sterling
patent: 3559480 (1971-02-01), Barber et al.
patent: 3650151 (1972-03-01), Drexel
patent: 3650505 (1972-03-01), Drexel
patent: 3792609 (1974-02-01), Blair et al.
patent: 3805610 (1974-04-01), Jacobs
patent: 3851526 (1974-12-01), Drexel
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patent: 3939858 (1976-02-01), LeMay
patent: 4056975 (1977-11-01), LeMay
patent: 4100801 (1978-07-01), LeMay
patent: 4255968 (1981-03-01), Harpster
Photocopy of Chapter 7, "Operational Amplifiers Design and Applications", published in 1971 (20 pages).
Document entitled "AFC-550 Automatic Flow Controller", bearing a copyright notice dated 1971 (24 pages).
Brochure dated Jun. 1977 entitled "Installation and Operating Instructions, Brooks Thermal Mass Flow Controller Model 5858", identified as Document No. X-5858 (18 pages).
Document entitled "Installation and Operating Instructions, Brooks Thermal Mass Flowmeter and Thermal Mass Flow Controller", dated Jan. 1979, identified as Document X-5810 (14 pages).
Document dated Feb. 1975 entitled "Operation and Service Manual Model FC260 Mass Flow Controller", from the Tylan Corporation (24 pages).
A group exhibit consisting of a plurality of bills of materials and drawings generated by applicant prior to the invention of instant application (12 drawings consisting of 37 pages).
Document generated by applicant entitled "MFC/Meter/Calibration", dated 2-4-76 (4 pages).
Document entitled "Operation and Service Manual, Models FM-360 and FM-361 Mass Flowmeters", from the Tylan Corp. (26 pages).
Undated and untitled document apparently from the Tylan Corp., which describes a Tylan GP-481 Hyoxcl "Burnt Hydrogen" Gas Control Panel (9 pages).
Untitled, undated document having subtitle "Single Op Amp Often Insufficient" (36 pages).
Untitled, undated document numbered respectively 96S, 101S, 103S, 104S, 105S and 326S, apparently provided by Analog Devices, Inc. (6 pages).
Untitled, undated sheet bearing the statement "Industry's First $49 D.P.M." (1 page).
Undated document generated by applicant entitled "Thermco Products Corporation Mass Flow Controller Model TFC772" (14 pages).
Undated document entitled "Procedure Assembly-TFC772", generated by applicant (7 pages).
Cohan Alan
Valentine James C.
Williamson John K.
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