US3757808A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electronic mass airflow sensing and control system
Assignee: Garrett Corp
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Filing: 1972-07-21
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Granted: 1973-09-11
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Expires: 1992-07-21
Abstract
Abstract Two sensing elements are disposed in a ducted fluid stream whose mass flow rate is to be sensed and is to be controlled by a valve. One sensing element provides a signal as a measure of the temperature of the fluid. The other element is electrically energized at a known power level so that it assumes a temperature different from that of the fluid, and experiences an exchange of enthalpy with the fluid. This element provides a signal as a measure of its own temperature. The two sensing elements are coupled with the valve in a closed loop relationship by electronic sensing and control circuitry. This circuitry processes the signals from the two sensing elements to generate a signal equivalent to the fluid mass flow rate, and causes control action to regulate the mass flow rate to a desired value. Other transducers may be coupled to the circuit to automatically reset the regulated flow rate as a function of other parameter signals which may be either dependent or independent of the properties of the fluid.
Inventors
- 👤 F Peterson
- 👤 G Paclik
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 15:39
CPC Classifications
G; G05; G05D; G05D7/00; G05D7/06; G05D7/0617; G05D7/0629; G05D7/0635; Y; Y10; Y10T; Y10T137/00; Y10T137/0318; Y10T137/0324; Y10T137/7722; Y10T137/7758; Y10T137/7761
Claims Analysis
Total Claims: 41
Claim 1
Independent Claim
92 words
Fluid flow apparatus comprising: a. control means for controlling flow of a fluid stream; b. first electrical signal generation means, including a first element disposed so as to sense a physical property of said fluid stream; c. second electrical signal generation means, including an electrically energized second element disposed to effect enthalpy exchange with the fluid in said fluid stream; and d. electrical circuit means coupling said first and second signal generating means to said control means so as to maintain a desired mass flow rate of fluid in said fluid stream.
Claim 2
Dependent Claim
92 words
Fluid flow apparatus comprising: a. control means for controlling flow of a fluid stream; b. first electrical signal generation means, including a first element disposed so as to sense a physical property of said fluid stream; c. second electrical signal generation means, including an electrically energized second element disposed to effect enthalpy exchange with the fluid in said fluid stream; and d. electrical circuit means coupling said first and second signal generating means to said control means so as to maintain a desired mass flow rate of fluid in said fluid stream.
Claim 3
Dependent Claim
25 words
The apparatus of claim 1 in which said first element comprises first temperature sensing means, and both said elements are disposed in said fluid stream.
Claim 4
Dependent Claim
26 words
The apparatus of claim 2 in which said second element comprises a heated device arranged to operate at a temperature above that of said fluid stream.
Claim 5
Dependent Claim
19 words
The apparatus of claim 3 in which said heated device is coupled to a source of regulated electrical power.
Claim 6
Dependent Claim
20 words
The apparatus of claim 4 in which said source of power applies a substantially constant voltage to said heated device.
Claim 7
Dependent Claim
23 words
The apparatus of claim 5 in which said heated device comprises a resistive heater element having a positive temperature coefficient of resistance characteristic.
Claim 8
Dependent Claim
31 words
The apparatus of claim 6 in which said second signal generation means includes means measuring the current in said heater device, said second signal being correlated to said heated device current.
Claim 9
Dependent Claim
20 words
The apparatus of claim 4 in which said source of power supplies a substantially constant current through said heated device.
Claim 10
Dependent Claim
24 words
The apparatus of claim 8 in which said heated device comprises a resistive heater element having a virtually zero temperature coefficient of resistance characteristic.
Claim 11
Dependent Claim
23 words
The apparatus of claim 9 in which said second signal generating means comprises a second temperature sensing means disposed adjacent said heated device.
Claim 12
Dependent Claim
34 words
The apparatus of claim 10 in which said heated device envelopes said second temperature sensing means so that said second temperature sensing meAns is subject substantially solely to the temperature of said heated device.
Claim 13
Dependent Claim
40 words
The apparatus of claim 1 further comprising third electrical signal generation means coupled to said circuit means, said third signal generation means including a third element disposed to so as to sense a physical state of a mass of matter.
Claim 14
Dependent Claim
40 words
The apparatus of claim 12 in which said third element comprises a temperature sensor and said third signal generation means provides a setpoint reference signal to said circuit means in accordance with the temperature sensed by said third element sensor.
Claim 15
Independent Claim
133 words
The method of controlling the mass flow rate of a fluid stream comprising the steps of: a. disposing a first sensor of a first electrical signal generation means in said fluid stream, said first sensor being adapted to sense a physical property manifestation of the fluid in said stream; b. disposing a second sensor of a second electrical signal generation means in said fluid stream, said second sensor being adapted to effect an enthalpy exchange with the fluid of said stream, said second signal generation means thereby providing a second electrical signal as a measure of the temperature of said second sensor; c. disposing an electrically controlled valve means in said fluid stream to control the flow thereof; and d. coupling said signals through a signal conditioning circuit means to said valve means.
Claim 16
Independent Claim
133 words
The method of controlling the mass flow rate of a fluid stream comprising the steps of: a. disposing a first sensor of a first electrical signal generation means in said fluid stream, said first sensor being adapted to sense a physical property manifestation of the fluid in said stream; b. disposing a second sensor of a second electrical signal generation means in said fluid stream, said second sensor being adapted to effect an enthalpy exchange with the fluid of said stream, said second signal generation means thereby providing a second electrical signal as a measure of the temperature of said second sensor; c. disposing an electrically controlled valve means in said fluid stream to control the flow thereof; and d. coupling said signals through a signal conditioning circuit means to said valve means.
Claim 17
Dependent Claim
53 words
The method of claim 14 in which said signal conditioning circuit means includes an electrical circuit selector element whose electrical property selection setting establishes a setpoint reference for a desired mass flow rate whereby said circuit means actuates said valve means to control said fluid stream flow to said mass flow rate setpoint.
Claim 18
Dependent Claim
21 words
The method of claim 14 in which said first electrical signal is a measure of the temperature of said fluid stream.
Claim 19
Dependent Claim
31 words
The method of claim 14 in which said second sensor comprises a heater operated at a temperature above that of said fluid stream with a substantially constant electrical power input thereto.
Claim 20
Dependent Claim
22 words
The method of claim 17 in which said second sensor includes a temperature sensitive element arranged to provide said second electrical signal.
Claim 21
Dependent Claim
21 words
The method of claim 14 in which said second sensor comprises means providing a measure of the electrical current flowing therein.
Claim 22
Dependent Claim
100 words
Fluid flow apparatus comprising: a. means defining the flow of a fluid stream; b. first electrical signal generation means, including a first element disposed so as to sense a physical property of said fluid stream; c. second electrical signal generation means, including an electrically energized second element disposed to effect enthalpy exchange with the fluid in said fluid stream; and d. electrical circuit means having input means coupled to said first and second signal generating means, and having output means providing a signal having a characteristic providing a measure of the mass flow rate of fluid in said fluid stream.
Claim 23
Dependent Claim
100 words
Fluid flow apparatus comprising: a. means defining the flow of a fluid stream; b. first electrical signal generation means, including a first element disposed so as to sense a physical property of said fluid stream; c. second electrical signal generation means, including an electrically energized second element disposed to effect enthalpy exchange with the fluid in said fluid stream; and d. electrical circuit means having input means coupled to said first and second signal generating means, and having output means providing a signal having a characteristic providing a measure of the mass flow rate of fluid in said fluid stream.
Claim 24
Dependent Claim
20 words
The apparatus of claim 20 in which said output signal is an electrical signal whose amplitude characteristic provides said measure.
Claim 25
Dependent Claim
25 words
The apparatus of claim 21 in which said first element comprises first temperature sensing means, and both said elements are disposed in said fluid stream.
Claim 26
Dependent Claim
26 words
The apparatus of claim 22 in which said second element comprises a heated device arranged to operate at a temperature above that of said fluid stream.
Claim 27
Dependent Claim
19 words
The apparatus of claim 23 in which said heated device is coupled to a source of regulated electrical power.
Claim 28
Dependent Claim
20 words
The apparatus of claim 24 in which said source of power applies a substantially constant voltage to said heated device.
Claim 29
Dependent Claim
30 words
The apparatus of claim 25 in which said heated device comprises a resistive heater element having a positive temperature coefficient of resistance characteristic, and having a known resistance temperature relationship.
Claim 30
Dependent Claim
31 words
The apparatus of claim 26 in which said secOnd signal generation means includes means measuring the current in said heater device, said second signal being correlated to said heated device current.
Claim 31
Dependent Claim
20 words
The apparatus of claim 24 in which said source of power supplies a substantially constant current through said heated device.
Claim 32
Dependent Claim
24 words
The apparatus of claim 28 in which said heated device comprises a resistive heater element having a virtually zero temperature coefficient of resistance characteristics.
Claim 33
Dependent Claim
23 words
The apparatus of claim 29 in which said second signal generating means comprises a second temperature sensing means disposed adjacent said heated device.
Claim 34
Dependent Claim
34 words
The apparatus of claim 30 in which said heated device envelopes said second temperature sensing means so that said second temperature sensing means is subject substantially solely to the temperature of said heated device.
Claim 35
Independent Claim
144 words
The method of measuring the mass flow rate of a fluid stream comprising the steps of: a. disposing of first sensor of a first electrical signal generation means in said fluid stream, said first sensor being adapted to sense a physical property manifestation of the fluid in said stream; b. disposing a second sensor of a second electrical signal generation means in said fluid stream, said second sensor being adapted to effect an enthalpy exchange with the fluid of said stream, said second signal generation means thereby providing a second electrical signal as a measure of the temperature of said second sensor; and c. coupling said first and second signal generation means to the input of signal conditioning circuit means, the output of which provides a signal having a characteristic providing a measure of the mass flow rate of fluid in said fluid stream.
Claim 36
Independent Claim
144 words
The method of measuring the mass flow rate of a fluid stream comprising the steps of: a. disposing of first sensor of a first electrical signal generation means in said fluid stream, said first sensor being adapted to sense a physical property manifestation of the fluid in said stream; b. disposing a second sensor of a second electrical signal generation means in said fluid stream, said second sensor being adapted to effect an enthalpy exchange with the fluid of said stream, said second signal generation means thereby providing a second electrical signal as a measure of the temperature of said second sensor; and c. coupling said first and second signal generation means to the input of signal conditioning circuit means, the output of which provides a signal having a characteristic providing a measure of the mass flow rate of fluid in said fluid stream.
Claim 37
Dependent Claim
25 words
The method of claim 32 in which the output of said signal conditioning circuit means provides an electrical signal whose amplitude characteristic provides said measure.
Claim 38
Dependent Claim
21 words
The method of claim 33 in which said first electrical signal is a measure of the temperature of said fluid stream.
Claim 39
Dependent Claim
31 words
The method of claim 33 in which said second sensor comprises a heater operated at a temperature above that of said fluid stream with a substantially constant electrical power input thereto.
Claim 40
Dependent Claim
22 words
The method of claim 35 in which said second sensor includes a temperature sensitive element arranged to provide said second electrical signal.
Claim 41
Dependent Claim
21 words
The method of claim 33 in which said second sensor comprises means providing a measure of the electrical current flowing therein.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-09-10 | 1977-03-12 | 1977-09-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-09-10 | 1981-03-12 | 1981-09-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-09-10 | 1985-03-12 | 1985-09-11 | $7700.00 | Window Closed / Lapsed |