Precision temperature and moisture content control for batch food production using a vacuum system

A method, for operating a precision temperature and moisture content control system for batch food production in an indirectly heated and agitated vessel with a vacuum system, comprising the steps of:

• providing a horizontally agitated and jacketed vacuum cooking vessel for said batch food production;
• wherein said precision temperature and moisture content control system are operative to provide at least one of a vacuum cooling process, a vacuum cooking process, and a combination of said vacuum cooking process and said vacuum cooling process;
• wherein an operative access and sealing port on said cooking vessel provides a batch access to said cooking vessel;
• providing a vacuum system herein a vacuum is drawn on said cooking vessel;
• wherein said vacuum system is a balanced vacuum duct system having a common plenum extending from said cooking vessel and two oppositely positioned isolation bellows communicating with a vacuum source whereby said vacuum system prevents imparting a vacuum force imbalance on said cooking vessel;
• wherein said precision temperature and moisture content control system further comprises a water metering system providing a make-up water to said cooking vessel;
• and
• wherein a heat exchanger system is an outboard heat exchanger operative to provide an indirect heat to said cooking vessel;
• providing a condensate removal tank system operably linked to said vacuum system and said cooking vessel to receive condensate;
• providing a weighing system having a plurality of load cells operative to measure a product weight under a vacuum condition or an atmospheric condition during said vacuum cooking process, said vacuum cooking process, or said combination of said vacuum cooking process and said vacuum cooling process;
• providing an interlinked programmable logic controller (PLC) or an industrial computer system receiving operating data including weight data, moisture data, and vacuum data;
• building a water latent heat of vaporization vs. temperature correlation into said interlinked programable logic controller (PLC) or said industrial computer with a numerical interpolation algorithm;
• building a product specific heat vs. moisture content correlation into said interlinked programable logic controller (PLC) or said industrial computer with a numerical interpolation algorithm;
• collecting and storing an empirical vacuum pressure vs. product boiling temperature data and determining a phase diagram correlation using said empirical data and storing said phase boundaries into said interlinked programable logic controller (PLC) or said industrial computer with a numerical interpolation algorithm, with an equation of the Clausius-Clapeyron equation type, or with an Antoine equation fitted using said empirical vacuum pressure vs. product boiling temperature data;
• entering and storing a product initial temperature, a moisture content, and a final temperature and moisture content target via a human-machine-interface (HMI) in said interlinked programable logic controller (PLC) or said industrial computer;
• determining, by built-in heat and mass balance equations stored in said interlinked programable logic controller (PLC) or said industrial computer, by automatic prediction whether a certain amount of make-up water needs to be added to said vacuum cooling process or said vacuum cooking process for said cooking vessel;
• operating said water metering system providing a make-up water to said cooking vessel to meet said certain amount of make-up water;
• and
• monitoring said a weighing system and said plurality of load cells and terminating said one of said vacuum cooking step, said vacuum cooling step, and said combination of said vacuum cooking and said vacuum cooling step.