US 4,410,030 A · Pressure cooker with regulated vapor pressure

Abstract

A pressure cooker regulates pressure over its range of cooking temperatures by regulating condensation and vaporization of contained water. Liquid water which has condensed upon a cooled surface collects in a thermally insulated condensate vessel and is vaporized therefrom by a heated surface to control the partial pressure of water vapor. The pressure cooker may also contain air at a predetermined pressure so that temperature can be controlled over a wide range of hot and cold temperatures as water vapor pressure is regulated to enable an increased range of food processing environments. In a preferred embodiment, the pressure cooker is part of a system of domestic appliances wherein a fluid circuit containing a liquid phase thermal exchange fluid includes thermal reservoirs to provide thermal inputs for the appliances. The pressure cooker has a primary heat exchanger which connects to the fluid circuit to attain desired food processing temperatures and has a secondary heat exchanger in the condensate vessel which connects to the fluid circuit to regulate partial pressure of water vapor by vaporization and condensation.

Claims11

Dependent claims

A process for regulating pressure in a processing vessel over a range of temperatures by regulating the partial pressure of a condensible gas, comprising the steps of:

cooling a surface which communicates with the processing vessel sufficiently to condense a portion of the condensible gas into its condensate and collecting the condensate in a condensate vessel which is thermally insulated from the processing vessel, said cooling continuing until the pressure in the processing vessel is reduced to a predetermined level, said cooled surface and condensate vessel being at substantially the pressure of the processing vessel, and
heating a surface which is in the condensate in the condensate vessel sufficiently to vaporize at least a portion of the condensate until the partial pressure of the condensible gas increases the pressure in the processing vessel to a predetermined level whereby the condensible gas and its condensate are conserved under transformation between gaseous and liquid phases to regulate pressure in the processing vessel.

A processing vessel with regulated pressure over a range of temperatures, comprising:

the processing vessel having means for attaining predetermined temperatures and containing a condensible gas and its condensate,
a condensate vessel communicating with the processing vessel and thermally insulated therefrom, said condensate vessel and processing vessel being at substantially the same pressure,
means for sensing pressure within the processing vessel and for comparing the sensed pressure to a setpoint pressure to determine a pressure error,
means for cooling a surface communicating with the condensate vessel on which cooled surface the condensible gas condenses to form the condensate and means for collecting the condensate in the condensate vessel, said means for cooling being responsive to the pressure error to reduce pressure for a high pressure error, and
means for heating a surface having a heat exchange relationship with the condensate in the condensate vessel to vaporize a portion of the condensate, said means for heating being responsive to the pressure error to increase pressure for a low pressure error whereby the condensible gas and its condensate are conserved under transformations between gaseous and liquid phases to regulate pressure in the processing vessel.

2 more elements

Dependencies are inferred from the claim text.

Pressure cooker with regulated vapor pressure

Life of this patent

Pressure cooker with regulated vapor pressure

Life of this patent

Abstract

Claims11