Low liquid volume retort method

Claim 1

A method of cooking and cooling food product filled containers within a pressure vessel having a tunnel therein which is arranged to receive the containers and which includes an inlet end and an overflow port at its outlet end that is disposed above the level of the containers in the tunnel, said tunnel also including external surfaces including an upper surface, said method requiring a minimum of heat treatment liquid comprising the steps of: loading the containers into the tunnel, closing the pressure vessel, directing a heated liquid at cooking temperature into the inlet end of said tunnel for flow through said tunnel and discharge from said overflow port during a cooking cycle, collecting the heated liquid overflowing from said port in a shallow pool within the lower portion of the pressure vessel externally of the tunnel and near the lower portion of the tunnel, directing a gaseous medium at superatmospheric pressure into said vessel to raise the pressure therein to a superatmospheric pressure in a manner so as to apply the gaseous medium at superatmospheric pressure directly against the upper surfaces of said shallow pool and said tunnel and directly against the external surfaces of the tunnel between the level of said overflow port and the upper surface of said shallow pool during the cooking cycle, continuously reheating and recirculating the heated liquid through the tunnel during the cooking cycle to maintain the amount of heated liquid in the shallow pool at a minimum until the cooking cycle is completed, discharging the heated liquid from the shallow pool and from the tunnel at the completion of the cooking cycle, directing a cooling liquid into the tunnel to cool the containers to a temperature below the boiling point of the heated liquid at atmospheric pressure during a cooling cycle, and thereafter removing the processed containers from the pressure vessel.

Claim 2

A method of cooking and cooling food product filled containers within a pressure vessel having a tunnel therein which is arranged to receive the containers and which includes an inlet end and an overflow port at its outlet end that is disposed above the level of the containers in the tunnel, said tunnel also including external surfaces including an upper surface, said method requiring a minimum of heat treatment liquid comprising the steps of: loading the containers into the tunnel, closing the pressure vessel, directing a heated liquid at cooking temperature into the inlet end of said tunnel for flow through said tunnel and discharge from said overflow port during a cooking cycle, collecting the heated liquid overflowing from said port in a shallow pool within the lower portion of the pressure vessel externally of the tunnel and near the lower portion of the tunnel, directing a gaseous medium at superatmospheric pressure into said vessel to raise the pressure therein to a superatmospheric pressure in a manner so as to apply the gaseous medium at superatmospheric pressure directly against the upper surfaces of said shallow pool and said tunnel and directly against the external surfaces of the tunnel between the level of said overflow port and the upper surface of said shallow pool during the cooking cycle, continuously reheating and recirculating the heated liquid through the tunnel during the cooking cycle to maintain the amount of heated liquid in the shallow pool at a minimum until the cooking cycle is completed, discharging the heated liquid from the shallow pool and from the tunnel at the completion of the cooking cycle, directing a cooling liquid into the tunnel to cool the containers to a temperature below the boiling point of the heated liquid at atmospheric pressure during a cooling cycle, and thereafter removing the processed containers from the pressure vessel.

Claim 9

A method of cooking and cooling food product filled containers disposed within a container supporting means having an outer surface and an overflow edge above the level of the uppermost containers in the supporting means while using a minimum of heat treatment liquid comprising the steps of: loading group of containers on the supporting means is spaced rows, directing a heated liquid at cooking temperature past the containers from one end of the supporting means to the other end for overflow over the edge, collecting the heated liquid overflowing from the container supporting means in a low volume pool having an upper surface and disposed against the lower portion and externally of the container supporting means, directing a gaseous medium at superatmospheric pressure externally of said container supporting means to prevent rupture of the containers and in a manner so as to apply the gaseous medium at superatmospheric pressure directly against the outer surface of the container supporting means between the level of said overflow edge and the upper surface of the low volume pool and directly against the upper surface of said low volume pool during the cooking cycle, continuously reheating and recirculating the heated liquid in equal amounts past all containers in the container supporting means during the cooking cycle to cook the product within all containers to the same degree and to maintain the quantity of heated liquid in the low volume pool at a minimum until the cooking cycle is completed, discharging the heated liquid from the low volume pool and from the container supporting means at the completion of the cooking cycle, directing a cooling medium into the container supporting means to cool the product within the containers below the boiling point of the heated liquid at atmospheric pressure during a cooling cycle while reducing the fluid pressure acting in aid containers to atmospheric pressure, and removing the processed containers from the container supporting means.

Claim 10

A method of cooking and cooling food product filled containers disposed within a container supporting means having an outer surface and an overflow edge above the level of the uppermost containers in the supporting means while using a minimum of heat treatment liquid comprising the steps of: loading group of containers on the supporting means is spaced rows, directing a heated liquid at cooking temperature past the containers from one end of the supporting means to the other end for overflow over the edge, collecting the heated liquid overflowing from the container supporting means in a low volume pool having an upper surface and disposed against the lower portion and externally of the container supporting means, directing a gaseous medium at superatmospheric pressure externally of said container supporting means to prevent rupture of the containers and in a manner so as to apply the gaseous medium at superatmospheric pressure directly against the outer surface of the container supporting means between the level of said overflow edge and the upper surface of the low volume pool and directly against the upper surface of said low volume pool during the cooking cycle, continuously reheating and recirculating the heated liquid in equal amounts past all containers in the container supporting means during the cooking cycle to cook the product within all containers to the same degree and to maintain the quantity of heated liquid in the low volume pool at a minimum until the cooking cycle is completed, discharging the heated liquid from the low volume pool and from the container supporting means at the completion of the cooking cycle, directing a cooling medium into the container supporting means to cool the product within the containers below the boiling point of the heated liquid at atmospheric pressure during a cooling cycle while reducing the fluid pressure acting in aid containers to atmospheric pressure, and removing the processed containers from the container supporting means.