Control system for electric water heater with heat pump external heat source
원문보기
IPC분류정보
국가/구분
United States(US) Patent
등록
국제특허분류(IPC7판)
H05B-001/02
F28F-027/00
F25B-029/00
F24H-001/00
출원번호
US-0570338
(1984-01-13)
발명자
/ 주소
Shaffer, Jr., Jacob E.
Picarello, Joseph F.
출원인 / 주소
Borg-Warner Corporation
대리인 / 주소
Schachner, Julian
인용정보
피인용 횟수 :
8인용 특허 :
1
초록▼
A control system for an electric water heater operatively associated with an external heat source, such as a heat pump. The water heater includes a water storage tank provided with an electric tank heating unit having a tank thermostat which closes in response to water temperature in the tank, allow
A control system for an electric water heater operatively associated with an external heat source, such as a heat pump. The water heater includes a water storage tank provided with an electric tank heating unit having a tank thermostat which closes in response to water temperature in the tank, allowing a flow of current through the tank heating unit so as to turn it on to heat the water, and which opens when the tank thermostat has been satisfied, interrupting the current flow so as to turn the tank heating unit off. The control system as responsive to the initial current surge through the tank heating unit when the tank thermostat closes to (1) interrupt the current flow to the tank heating unit so as to maintain the heating unit off and (2) to turn on the external heat source and maintain it on until the tank thermostat opens. The initial current surge cleans the contacts of the tank thermostat by burning off any insulating oxide residues which may have formed on them. The control system includes means responsive to abnormal conditions which would prevent the external heat source from heating water effectively for (1) turning off the external heat source and turning on the tank heating unit and (2) maintaining the external heat source off and the tank heating unit on until the tank thermostat is satisfied.
대표청구항▼
1. A control system for a water heater operatively associated with an external heat source, said water heater including a water storage tank and an electric tank heating unit, said tank heating unit having at least one tank thermostat responsive to water temperature in said tank, said tank thermosta
1. A control system for a water heater operatively associated with an external heat source, said water heater including a water storage tank and an electric tank heating unit, said tank heating unit having at least one tank thermostat responsive to water temperature in said tank, said tank thermostat closing when there is a demand for hot water in said tank thereby allowing a current to flow through said tank heating unit so as to turn it on and opening when the demand has been satisfied thereby interrupting the current flow through said tank heating unit so as to turn it off, said control system comprising means responsive to an initial current surge through said tank heating unit when said tank thermostat closes both for interrupting the current flow so as to maintain said tank heating unit off and for turning said external heat source on, the initial current surge cleaning the contacts of said tank thermostat by burning off any residue thereon. 2. The control system of claim 1, further comprising additional means responsive to at least one external condition for turning off said external heat source, turning on said tank heating unit, and maintaining said external heat source off and said tank heating unit on until said tank thermostat opens. 3. The control system of claim 2, said means including a current relay having a normally open contact set, a first time-off delay relay having a normally closed contact set and a normally open contact set, and a second time-off delay relay of the high-impedance type having a normally open contact set, said tank heating unit, current relay and first relay normally closed contact set being connected in series across first and second terminals to which a voltage may be applied, said external heat source and said first relay normally open contact set being connected in series across said terminals, said first relay and the parallel combination of said current relay contact set and second relay contact set being coupled in series across said terminals, and said tank heating unit and said second relay being connected in series across said terminals. 4. The control system of claim 3, said additional means including at least one external sensor, and a third relay having a normally closed contact set and a normally open contact set, said third relay, the parallel combination of said external sensor and third relay normally open contact set, and the parallel combination of said current relay contact set and second relay contact set being connected in series across said terminals, and said third relay normally closed contact set being connected in series with said first relay and the parallel combination of said current relay contact set and second relay contact set. 5. The control system of claim 2, said means including a current sensor having an output which is high when current flow is sensed, a first comparator having first and second inputs and an output which is high when the voltage levels at its inputs are unequal, a resistor connecting said inputs of said first compartor, a time-off delay relay having a normally closed contact set and a normally open contact set, said tank heating unit, current sensor and normally closed contact set forming a series connection across first and second terminals to which a voltage may be applied, said tank heating unit being connected to said second terminal, said first input of said first comparator being connected to said series connection between said tank heating unit and said normally closed contact set, said second input of said first compartor being connected to said first terminal, said normally open contact set and said external heat source being connected in series across said first and second terminals, an OR gate having first and second inputs respectively connected to said current sensor output and said first comparator output, said OR gate having an output which is high when either of its inputs is high, and a time delay having an input connected to said OR gate output and an output, said relay being coupled to said time delay output and connected to said second terminal. 6. The control system of claim 5, said additional means including a latch having set and reset inputs and an output which is high when its reset input is low and which, when its reset input is high, goes low when its set input goes low and remains low until its reset input goes low again, said reset input being connected to said time delay output, an AND gate having first and second inputs respectively connected to said latch output and said time delay output, said AND gate also having an output which is high when both of its inputs are high, said relay being coupled to said time delay output by being connected to said AND gate output, a second comparator having first and second inputs and an output which is low when the voltage levels at its inputs are unequal, another resistor connecting said inputs of said second comparator, and an external sensor connected to said first input of said second comparator and said second terminal, said second input of said second comparator being connected to said first terminal, and said output of said second comparator being connected to said set input of said latch. 7. The control system of claim 1, said means including a current relay having a normally open contact set, a first time-off delay relay having a normally closed contact set and a normally open contact set, and a second time-off delay relay of the high-impedance type having a normally open contact set, said tank heating unit, current relay and first relay normally closed contact set being connected in series across first and second terminals to which a voltage may be applied, said external heat source and said first relay normally open contact set being connected in series across said terminals, said first relay and the parallel combination of said current relay contact set and second relay contact set being coupled in series across said terminals, and said tank heating unit and said second relay being connected in series across said terminals. 8. The control system of claim 1, said means including a current sensor having an output which is high when current flow is sensed, a first comparator having first and second inputs and an output which is high when the voltage levels at its inputs are unequal, a resistor connecting said inputs of said first comparator, a time-off delay relay having a normally closed contact set and a normally open contact set, said tank heating unit, current sensor and normally closed contact set forming a series connection across first and second terminals to which a voltage may be applied, said tank heating unit being connected to said second terminal, said first input of said first comparator being connected to said series connection between said tank heating unit and said normally closed contact set, said second input of said first comparator being connected to said first terminal, said normally open contact set and said external heat source being connected in series across said first and second terminals, an OR gate having first and second inputs respectively connected to said current sensor output and said first comparator output, said OR gate having an output which is high when either of its inputs is high, and a time delay having an input connected to said OR gate output and an output, said relay being coupled to said time delay output and connected to said second terminal.
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이 특허에 인용된 특허 (1)
Sanborn, David M.; Blackshaw, Andrew L., Connection assembly.
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