US4027497A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Freeze-up prevention device for a heat pump
Assignee: Individual
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Filing: 1976-02-26
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Granted: 1977-06-07
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Expires: 1996-02-26
Abstract
Abstract The present invention relates to heat pumps which include a freeze-up prevention device for use during the heating cycle. The heat pump consists of the normal compressor which connects by means of a four-way valve to an inside coil and an outside coil. An expansion valve and appropriate check valve allow the flow of refrigerant between the inside and outside coils. During the heating cycle, the inside coil is the condenser and the outside is the evaporator. The freeze-up prevention device is a small insertable unit immediately prior to the evaporator which allows the refrigerant to flow therethrough. The insertable unit has a heating element operable by a thermostat attached to the outside coils with the thermostat closing a switch to allow current to flow to the heating element when an icing condition is sensed. The insertable unit, via the heating element, transmits heat directly to the refrigerant thereby preventing freeze-up of the evaporator coil.
Inventors
- 👤 Merrell E. Thurman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 15:11
CPC Classifications
F; F25; F25D; F25D21/00; F25D21/04; F25B; F25B13/00; F25B47/00; F25B47/006
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
249 words
A heat pump system for alternately heating and cooling a given space, said system comprising: a source of power; a compressor driven by the source of power, said compressor having an inlet and outlet; valve means connecting to said inlet and outlet; inside coil located within said given space; outside coil located outside said given space; said valve means connecting said inlet to said inside coil and said outlet to said outside coil for cooling, and alternatively connecting said inlet to said outside coil and said outlet to said inside coil for heating, said inside and outside coils being adapted to receive a refrigerant from said compressor; expansion valve means connected to said inside coil for allowing said refrigerant to flow therethrough, said refrigerant being at a high pressure liquid state on one side of said expansion valve means and at a low pressure liquid state after flowing through said expansion means; sensing means for sensing freeze-up conditions on said outside coil; freeze-up prevention means disposed between said expansion valve means and said outside coil for receiving said refrigerant therethrough, said freeze-up prevention being responsive to said sensing means upon sensing said freeze-up conditions to connect a heating element to said source of power for adding heat to said refrigerant if ice begins to accumulate on said outside coil during heating of said given space, said heating element being generally pie-shaped and sandwiched between parallel, generally pie-shaped conduit means from said expansion valve means for maximum heat transfer thereto.
Claim 2
Dependent Claim
249 words
A heat pump system for alternately heating and cooling a given space, said system comprising: a source of power; a compressor driven by the source of power, said compressor having an inlet and outlet; valve means connecting to said inlet and outlet; inside coil located within said given space; outside coil located outside said given space; said valve means connecting said inlet to said inside coil and said outlet to said outside coil for cooling, and alternatively connecting said inlet to said outside coil and said outlet to said inside coil for heating, said inside and outside coils being adapted to receive a refrigerant from said compressor; expansion valve means connected to said inside coil for allowing said refrigerant to flow therethrough, said refrigerant being at a high pressure liquid state on one side of said expansion valve means and at a low pressure liquid state after flowing through said expansion means; sensing means for sensing freeze-up conditions on said outside coil; freeze-up prevention means disposed between said expansion valve means and said outside coil for receiving said refrigerant therethrough, said freeze-up prevention being responsive to said sensing means upon sensing said freeze-up conditions to connect a heating element to said source of power for adding heat to said refrigerant if ice begins to accumulate on said outside coil during heating of said given space, said heating element being generally pie-shaped and sandwiched between parallel, generally pie-shaped conduit means from said expansion valve means for maximum heat transfer thereto.
Claim 3
Dependent Claim
39 words
The heat pump as given in claim 1 wherein said heating element is of an electrical resistance type, said sensing means closing switch means to allow current received from said source of power to flow through said heating element.
Claim 4
Dependent Claim
29 words
The heat pump as given in claim 2 further including a solenoid means connected to said sensing means, said solenoid means closing said switch means upon current flow therethrough.
Claim 5
Dependent Claim
180 words
A freeze-up prevention device for use with a heat pump system having a source of electrical power, a source of refrigerant, an expansion valve, a condenser coil and an evaporator coil, said heat pump system having a heating and cooling cycle, said freeze-up prevention device comprising: first connector means for receiving refrigerant from said expansion valve; parallel conduit means connected to said first connector means to receive refrigerant therefrom, said parallel conduit means being of a generally flat spiral shape in a spaced apart relationship; resistance heating element located in said space between said parallel conduit means; second connector means for connecting said parallel conduit means to said evaporator coil to allow refrigerant to flow thereto; switching means for connecting said resistance heating element to said electrical power source; and sensor means for detecting ice accumulation on said evaporator coil, said sensor means controlling operation of said switching means, current flow through said switching means and to said resistance heating element thereby causing heat to be absorbed from said resistance heating element by refrigerant flowing through said parallel conduit means.
Claim 6
Dependent Claim
180 words
A freeze-up prevention device for use with a heat pump system having a source of electrical power, a source of refrigerant, an expansion valve, a condenser coil and an evaporator coil, said heat pump system having a heating and cooling cycle, said freeze-up prevention device comprising: first connector means for receiving refrigerant from said expansion valve; parallel conduit means connected to said first connector means to receive refrigerant therefrom, said parallel conduit means being of a generally flat spiral shape in a spaced apart relationship; resistance heating element located in said space between said parallel conduit means; second connector means for connecting said parallel conduit means to said evaporator coil to allow refrigerant to flow thereto; switching means for connecting said resistance heating element to said electrical power source; and sensor means for detecting ice accumulation on said evaporator coil, said sensor means controlling operation of said switching means, current flow through said switching means and to said resistance heating element thereby causing heat to be absorbed from said resistance heating element by refrigerant flowing through said parallel conduit means.
Claim 7
Dependent Claim
47 words
The freeze-up prevention device as given in claim 4 wherein said resistance heating element is of a generally flat spiral shape so that space between said parallel conduit means is minimum for a maximum heat transfer to the refrigerant upon current flow through said resistance heating element.
Claim 8
Dependent Claim
43 words
The freeze-up prevention device as given in claim 5 wherein said sensor means includes a control switch adapted to close if temperature of said evaporator coil drops below a predetermined point, closure of said control switch providing said control of said switching means.
Claim 9
Dependent Claim
33 words
The freeze-up prevention device as given in claim 6 wherein said closure of said control switch allowing current to flow through a solenoid, flow of current through said solenoid controlling said switching means.
Claim 10
Dependent Claim
28 words
The freeze-up prevention device as given in claim 4 wherein said first and second connector means are hand operable for ease of installation of said freeze-up prevention device.
Claim 11
Dependent Claim
32 words
The freeze-up prevention device as given in claim 5 further including a clamp means for holding said flat spiral shaped parallel conduit means and resistance heating element in a flat abutting relationship.
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) | 1980-06-06 | 1980-12-06 | 1981-06-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-06-06 | 1984-12-06 | 1985-06-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-06-06 | 1988-12-06 | 1989-06-07 | $7700.00 | Window Closed / Lapsed |