US4026321A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electronic control for constant and variable volume central heating and air-conditioning systems
Assignee: KAHOE LABS Inc
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Filing: 1975-12-12
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Granted: 1977-05-31
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Expires: 1995-12-12
Abstract
Abstract A control system for use in central heating and air-conditioning installations to control the volumetric flow rate of conditioned air through a supply duct to an enclosed space to be serviced. The system is adapted to maintain a desired ambiant temperature in the enclosed space by regulating the circulation of conditioned air in accordance with the demand generated by prevailing conditions. An adjustable restrictor valve defining an orifice is located in the supply duct and sensors are provided to continuously measure the orifice diameter and the pressure drop across the orifice. Electronic circuitry is provided to generate a flow rate voltage signal representative of the product of the orifice diameter and the pressure drop across the orifice and to compare the flow rate voltage level with a fixed or temperature controlled reference voltage to obtain either an "increase" or "decrease" control voltage signal. An "increase" control signal is used to enlarge the orifice diameter and increase the volumetric flow rate while a "decrease" control signal is used to decrease the flow rate and reduce the orifice diameter.
Inventors
- 👤 H. Taylor Kahoe
- 👤 George E. Coultas
- 👤 Dana W. Skipworth
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 11:18
CPC Classifications
G; G05; G05D; G05D23/00; G05D23/19; F; F24; F24F; F24F11/00; F24F11/70; F24F11/72; F24F11/74; Y; Y10; Y10T; Y10T137/00; Y10T137/7722; Y10T137/7758; Y10T137/7759; Y10T137/776; Y10T137/7761
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
190 words
Apparatus for controlling the flow rate of conditioned air through a supply duct to an enclosed space for maintaining a desired ambient temperature therein comprising: adjustable flow restrictor means located in said duct and defining an orifice, control means for adjusting the size of said orifice, means for generating a first electrical voltage signal representative of the logarithm of the square of a dimension of said orifice, means for generating a second electrical voltage signal representative of the logarithm of the square root of the pressure differential across said orifice summation circuit means for electrically adding said first and second electrical voltage signals to produce a summation voltage signal, means for comparing said summation voltage signal with a predetermined reference voltage level and for generating an "increase" control voltage signal when said summation voltage signal is greater than said reference voltage level and a "decrease" voltage signal when said summation voltage signal is less than said reference voltage level, means responsive to said "increase" control voltage signal for reducing the size of said orifice, and means responsive to said "decrease" control voltage signal for increasing the size of said orifice.
Claim 2
Dependent Claim
190 words
Apparatus for controlling the flow rate of conditioned air through a supply duct to an enclosed space for maintaining a desired ambient temperature therein comprising: adjustable flow restrictor means located in said duct and defining an orifice, control means for adjusting the size of said orifice, means for generating a first electrical voltage signal representative of the logarithm of the square of a dimension of said orifice, means for generating a second electrical voltage signal representative of the logarithm of the square root of the pressure differential across said orifice summation circuit means for electrically adding said first and second electrical voltage signals to produce a summation voltage signal, means for comparing said summation voltage signal with a predetermined reference voltage level and for generating an "increase" control voltage signal when said summation voltage signal is greater than said reference voltage level and a "decrease" voltage signal when said summation voltage signal is less than said reference voltage level, means responsive to said "increase" control voltage signal for reducing the size of said orifice, and means responsive to said "decrease" control voltage signal for increasing the size of said orifice.
Claim 3
Dependent Claim
18 words
Apparatus as defined in claim 1 wherein said adjustable flow restrictor means comprises an iris type flow valve.
Claim 4
Dependent Claim
66 words
Apparatus as defined in claim 1 wherein said means for generating a first electrical voltage signal representative of the logarithm of the square of a dimension of said orifice comprises: means for generating an initial voltage signal representative of said dimension of said orifice, a logarithmic amplifier for amplifying said initial voltage signal and electrical squaring circuit means for electrically squaring said amplified initial voltage signal.
Claim 5
Dependent Claim
74 words
Apparatus as defined in claim 1 wherein said means for generating a second electrical voltage signal representative of the logarithm of the square root of the pressure differential across said orifice comprises: means for generating an initial voltage signal representative of said pressure differential across said orifice, a logarithmic amplifier for amplifying said initial voltage signal and electrical square root circuit means for electrically producing the square root of said amplified initial voltage signal.
Claim 6
Dependent Claim
199 words
Apparatus for controlling the flow rate of conditioned air through a supply duct to an enclosed space for maintaining a desired ambient temperature therein comprising: adjustable flow restrictor means located in said duct and defining an orifice, a fluid cylinder operatively connected to said flow restrictor means, a source of fluid pressure, a two-way valve operated by solenoids operatively connected between said cylinder and said fluid pressure source for adjusting the diameter of said orifice, means for generating an electrical voltage signal that is a function of a dimension of said orifice and the pressure differential across said orifice, means for comparing said voltage signal with a predetermined reference voltage level and for generating an "increase" control voltage signal when said voltage signal is greater than said reference level and a "decrease" control voltage signal when said voltage signal is less than said reference level means responsive to said "increase" control voltage signal for reducing the diameter of said orifice, and means responsive to said "decrease" control voltage signal for increasing the diameter of said orifice, one of said solenoids being responsive to said "increase" control voltage signal and the other being responsive to said "decrease" control voltage signal.
Claim 7
Dependent Claim
199 words
Apparatus for controlling the flow rate of conditioned air through a supply duct to an enclosed space for maintaining a desired ambient temperature therein comprising: adjustable flow restrictor means located in said duct and defining an orifice, a fluid cylinder operatively connected to said flow restrictor means, a source of fluid pressure, a two-way valve operated by solenoids operatively connected between said cylinder and said fluid pressure source for adjusting the diameter of said orifice, means for generating an electrical voltage signal that is a function of a dimension of said orifice and the pressure differential across said orifice, means for comparing said voltage signal with a predetermined reference voltage level and for generating an "increase" control voltage signal when said voltage signal is greater than said reference level and a "decrease" control voltage signal when said voltage signal is less than said reference level means responsive to said "increase" control voltage signal for reducing the diameter of said orifice, and means responsive to said "decrease" control voltage signal for increasing the diameter of said orifice, one of said solenoids being responsive to said "increase" control voltage signal and the other being responsive to said "decrease" control voltage signal.
Claim 8
Dependent Claim
201 words
Apparatus for controlling the flow rate of conditioned air through a supply duct to an enclosed space for maintaining a desired ambient temperature therein comprising: means located in said duct defining a flow restriction, control means for adjusting the cross sectional area of said flow restriction, means for generating a first electrical voltage signal representative of the logarithm of the square of a dimension of said area of said restriction, means for generating a second electrical voltage signal representative of the logarithm of the square root of a pressure differential produced by the velocity of conditioned air downstream of said restriction, summation circuit means for electrically adding said first and second electrical voltage signals to produce a summation voltage signal, means for comparing said summation voltage signal with a predetermined reference voltage level and for generating an "increase" control voltage signal when said summation voltage signal is greater than said reference voltage level and a "decrease" voltage signal when said summation voltage signal is less than said reference voltage level, means responsive to said "increase" control voltage signal for reducing the area of said restriction, and means responsive to said "decrease" control voltage signal for increasing the area of said restriction.
Claim 9
Dependent Claim
201 words
Apparatus for controlling the flow rate of conditioned air through a supply duct to an enclosed space for maintaining a desired ambient temperature therein comprising: means located in said duct defining a flow restriction, control means for adjusting the cross sectional area of said flow restriction, means for generating a first electrical voltage signal representative of the logarithm of the square of a dimension of said area of said restriction, means for generating a second electrical voltage signal representative of the logarithm of the square root of a pressure differential produced by the velocity of conditioned air downstream of said restriction, summation circuit means for electrically adding said first and second electrical voltage signals to produce a summation voltage signal, means for comparing said summation voltage signal with a predetermined reference voltage level and for generating an "increase" control voltage signal when said summation voltage signal is greater than said reference voltage level and a "decrease" voltage signal when said summation voltage signal is less than said reference voltage level, means responsive to said "increase" control voltage signal for reducing the area of said restriction, and means responsive to said "decrease" control voltage signal for increasing the area of said restriction.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-05-30 | 1980-11-29 | 1981-05-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-05-30 | 1984-11-29 | 1985-05-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-05-30 | 1988-11-29 | 1989-05-31 | $7700.00 | Window Closed / Lapsed |