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US 4,290,551 AGranted
Automatic temperature compensated boiler thermostat
AssigneeCarco Accessories Limited
InventorFrank Johnstone
Life of this patent
Estimating the term…
Abstract
A control apparatus for a fuel fired central heating boiler has a first temperature control circuit including a first thermistor for sensing external ambient temperature and a second thermistor for sensing the temperature of the circulating water produced by the boiler. A second temperature control circuit has a thermistor for sensing the temperature in the space to be heated. A relay is operated by the outputs of the first and second control circuits and itself controls the boiler. The first and second thermistors are connected in series and have different resistance/temperature characteristics so that a given change in the external ambient temperature corresponds to a greater change in the temperature of the circulating water.
Claims15
A control apparatus for a fuel fired central heating boiler providing circulating heating water for space heating comprising:
- a first temperature control circuit for controlling the firing of said boiler and the temperature of said circulating heating water including a first temperature sensitive element for sensing an external ambient temperature and a second temperature sensitive element for sensing the temperature of said circulating heating water, said first and second temperature sensitive elements being connected in series and having different resistance/temperature characteristics from one another such that a change in said external ambient temperature corresponds to a greater change in the temperature of said circulating heating water and determines a maximum slope of temperature change within said circulating heating water for a given external ambient temperature;
- a second temperature control circuit including a third temperature sensitive element for sensing the temperature in a space to be heated and in response thereto for controlling the firing of said boiler and the circulation of said circulating heating water and arranged to determine automatically the slope of the temperature change within said circulating heating water below said maximum slope;
- and
- an output circuit for controlling the firing of said boiler coupled to both said first and second temperature control circuits and adapted to be responsive to said first temperature control circuit and/or said second temperature control circuit.
1 more element
A fuel fired central heating boiler having a circulating heating water for space heating and a control apparatus comprising:
- a first temperature control circuit for controlling the firing of said boiler and the temperature of said circulating heating water including a first temperature sensitive element for sensing an external ambient temperature and a second temperature sensitive element for sensing the temperature of said circulating heating water, said first and second temperature sensitive elements being connected in series and having different resistance/temperature characteristics from one another such that a change in said external ambient temperature corresponds to a greater change in the temperature of said circulating heating water and determines a maximum slope of temperature change within said circulating heating water for a given external ambient temperature;
- a second temperature control circuit including a third temperature sensitive element for sensing the temperature in a space to be heated and in response thereto for controlling the firing of said boiler and the circulation of said circulating heating water and arranged to determined automatically the slope of the temperature change within said circulating heating water below said maximum slope;
- and
- an output circuit for controlling the firing of said boiler coupled to both said first and second temperature control circuits and adapted to be responsive to said first temperature control circuit and/or said second temperature control circuit.
1 more element
A control apparatus for a fuel fired central heating boiler providing a circulating heating medium for space heating comprising:
- a first temperature control circuit for controlling the firing of said boiler and the temperature of said circulating heating medium including a first temperature sensitive element for sensing an external ambient temperature and a second temperature sensitive element for sensing the temperature of said circulating heating medium, said first and second temperature sensitive elements being connected in series and having different resistance/temperature characteristics from one another such that a change in said external ambient temperature corresponds to a greater change in the temperature of said circulating heating medium and determines a maximum slope of temperature change within said circulating heating medium for a given external ambient temperature;
- a second temperature control circuit including a third temperature sensitive element for sensing the temperature in a space to be heated and in response thereto for controlling the firing of said boiler and the circulation of said circulating heating medium and arranged to determine automatically the slope of the temperature change within said circulating heating medium below said maximum slope;
- and
- an output circuit for controlling the firing of said boiler coupled to both said first and second temperature control circuits and adapted to be responsive to said first temperature control circuit and/or said second temperature control circuit.
1 more element
A fuel fired central heating boiler having a circulating heating medium and a control apparatus comprising:
- a first temperature control circuit for controlling the firing of said boiler and the temperature of said circulating heating medium including a first temperature sensitive element for sensing an external ambient temperature and a second temperature sensitive element for sensing the temperature of said circulating heating medium, said first and second temperature sensitive elements being connected in series and having different resistance/temperature characteristics from one another such that a change in said external ambient temperature corresponds to a greater change in the temperature of said circulating heating medium and determines a maximum slope of temperature change within said circulating heating medium for a given external ambient temperature;
- a second temperature control circuit including a third temperature sensitive element for sensing the temperature in a space to be heated and in response thereto for controlling the firing of said boiler and the circulation of said circulating heating medium and arranged to determine automatically the slope of the temperature change within said circulating heating medium below said maximum slope;
- and
- an output circuit for controlling the firing of said boiler coupled to both said first and second temperature control circuits and adapted to be responsive to said first temperature control circuit and/or said second temperature control circuit.
1 more element
Dependencies are inferred from the claim text.