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US 3,977,387 AGranted
Temperature-controlled oven
AssigneeBlue M Electric Company
InventorJoseph A. Lawler
Life of this patent
Estimating the term…
Abstract
Inherent heating of the air in an oven by a high-velocity recirculating blower is used as constant rate thermal energy source. Constant temperature is maintained by varying the rate of blending of source of cooler air with the heated oven air. Automatic control of temperature is provided by a variable vent operated by a thermal expansion bellows, and a second control means is employed to prevent the oven from exceeding an adjustable maximum temperature.
Claims10
A temperature-controlled oven comprising, in combination:
- a. an outer thermal-insulation leakage sealed enclosure,
- b. an inner chamber within the enclosure adapted to receive bodies to be maintained at constant temperature and having gas inlet and gas outlet portions,
- c. gas recirculation means within the enclosure adjacent to the inner chamber including a constant speed gas blower and gas duct means guiding outlet gas from the chamber back to the inlet portion, said gas blower constituting a heat source for said oven,
- d. a source of gas exterior of the emclosure at constant temperature different than the inner chamber,
- e. a gas inlet vent and a gas outlet vent through the enclosure in regions of differing internal gas pressure, said inlet vent communicating with the source of gas and continuously blending gas from the source into the gas duct means for recirculating gas within the enclosure,
- f. a first control means on at least one of said vents responsive to the oven temperature to vary the rate of blending of gas from the source of gas to the gas duct means, and
- g. a second control means on at least one of said vents responsive to a threshold temperature within the inner chamber to couple the inner chamber to the source of gas for blending gas from the source with gas in the inner chamber at a rate greater than the blending rate of gas from the source established by the first control means.
4 more elements
A temperature-controlled oven comprising, in combination:
- a. an outer thermal insulation leakage sealed enclosure.
- b. an inner chamber within the enclosure adapted to receive bodies and having air inlet and air outlet portions,
- c. air recirculation means within the enclosure adjacent to the inner chamber including an air blower and air duct means guiding air from the outlet portion of the chamber back to the inlet portion, and
- d. means coupled to the air recirculation means responsive to a threshold temperature within the inner chamber to open the inner chamber to the ambient atmosphere comprising means defining a port extending from the air duct means through the enclosure and communicating with the ambient atmosphere, closure means mounted adjacent to the port having a member movable between a first position in which the port is unrestricted and a second position in which the port is restricted, positioning means for said movable member normally positioning the movable member in the second position, said positioning means moving the movable member responsive to an increase in temperature within the inner chamber above the threshold value to position the closure mechanism in the first position to permit the ambient atmosphere to freely enter the chamber.
1 more element
Dependencies are inferred from the claim text.