US3691785A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Small centrifugal heat pump
Assignee: Individual
•
Filing: 1970-05-15
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Granted: 1972-09-19
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Expires: 1990-05-15
Abstract
Abstract A variable capacity mechanical refrigeration system for heat pump or cooling operation, with a variable speed centrifugal compressor motor drive that uses an electronic frequency conversion apparatus which is sensitive to and controlled by, discharge or suction pressure and which includes means of preventing overloading during start up of the compressors.
Inventors
- 👤 John D Ruff
- 👤 Phillip R Wheeler
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 04:27
CPC Classifications
F; F25; F25B; F25B49/00; F25B49/02; F25B49/025; F24; F24F; F24F3/00; F24F3/001; F25B49/022; F25B2600/00; F25B2600/02; F25B2600/025; F25B2600/0253; Y; Y02; Y02B; Y02B30/00; Y02B30/70
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
210 words
In combination a variable capacity heat pump used for heating an air filled space and comprising kinetic displacement vapor compression means direct driven by variable frequency, alternating current, electric motor machinery of the squirrelcage induction type and the said compression means and motor machinery being combined in a common hermetic enclosure, to pump refrigerant vapor from a dry expansion evaporator to a condenser, a variable frequency inverter means using sequential switching equipment to switch electrical current from an external source into the windings of the said motor machinery in such a manner to provide a variable frequency flux through the said windings, and thus achieve a variable speed rotation of the said motor machinery, since the rotation speed of this type of motor is dependent on the frequency of the current supplied to it, a pressure sensing means which is sensitive only to the refrigerant vapor pressUre in the said condenser, and the frequency of the said variable frequency inverter is controlled by this said pressure sensing means so that when operating conditions cause the pressure in the said condenser to be undesirably low the compressor is speeded up until a suitable condenser pressure is reached and similarly when the condenser pressure is too high the compressor is slowed down.
Claim 2
Dependent Claim
210 words
In combination a variable capacity heat pump used for heating an air filled space and comprising kinetic displacement vapor compression means direct driven by variable frequency, alternating current, electric motor machinery of the squirrelcage induction type and the said compression means and motor machinery being combined in a common hermetic enclosure, to pump refrigerant vapor from a dry expansion evaporator to a condenser, a variable frequency inverter means using sequential switching equipment to switch electrical current from an external source into the windings of the said motor machinery in such a manner to provide a variable frequency flux through the said windings, and thus achieve a variable speed rotation of the said motor machinery, since the rotation speed of this type of motor is dependent on the frequency of the current supplied to it, a pressure sensing means which is sensitive only to the refrigerant vapor pressUre in the said condenser, and the frequency of the said variable frequency inverter is controlled by this said pressure sensing means so that when operating conditions cause the pressure in the said condenser to be undesirably low the compressor is speeded up until a suitable condenser pressure is reached and similarly when the condenser pressure is too high the compressor is slowed down.
Claim 3
Dependent Claim
210 words
In combination a variable capacity cooling system used for cooling an air filled space and comprising kinetic displacement vapor compression means direct driven by variable frequency, alternating current, electric motor machinery of the squirrel-cage induction type and the said compression means and motor machinery being combined in a common hermetic enclosure, to pump refrigerant vapor from a dry expansion evaporator to a condenser, a variable frequency inverter means using sequential switching equipment to switch electrical current from an external source into the windings of the said motor machinery in such a manner to provide a variable frequency flux through the said windings, and thus achieve a variable speed rotation of the said motor machinery, since the rotation speed of this type of motor is dependent on the frequency of the current supplied to it, a pressure sensing means which is sensitive only to the refrigerant vapor pressure in the said evaporator, and the frequency of the said variable frequency inverter is controlled by this said pressure sensing means so that when operating conditions cause the pressure in the said evaporator to be undesirably high the compressor is speeded up till a suitable evaporator pressure is reached and similarly when the evaporator pressure is too low the compressor is slowed down.
Claim 4
Dependent Claim
210 words
In combination a variable capacity cooling system used for cooling an air filled space and comprising kinetic displacement vapor compression means direct driven by variable frequency, alternating current, electric motor machinery of the squirrel-cage induction type and the said compression means and motor machinery being combined in a common hermetic enclosure, to pump refrigerant vapor from a dry expansion evaporator to a condenser, a variable frequency inverter means using sequential switching equipment to switch electrical current from an external source into the windings of the said motor machinery in such a manner to provide a variable frequency flux through the said windings, and thus achieve a variable speed rotation of the said motor machinery, since the rotation speed of this type of motor is dependent on the frequency of the current supplied to it, a pressure sensing means which is sensitive only to the refrigerant vapor pressure in the said evaporator, and the frequency of the said variable frequency inverter is controlled by this said pressure sensing means so that when operating conditions cause the pressure in the said evaporator to be undesirably high the compressor is speeded up till a suitable evaporator pressure is reached and similarly when the evaporator pressure is too low the compressor is slowed down.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-09-19 | 1976-03-20 | 1976-09-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-09-19 | 1980-03-20 | 1980-09-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-09-19 | 1984-03-20 | 1984-09-19 | $7700.00 | Window Closed / Lapsed |