A CO2 safety interlock fill system configured to perform pre-fill integrity checks for automatically leak checking a fill manifold and pressurizing the fill manifold, said pre-fill integrity checks for the leak checking and the pressurizing of the fill manifold performed prior to the CO2 safety interlock fill system allowing a subsequent filling operation of liquefied carbon dioxide (CO2) product into a container from an onsite CO2 source, said CO2 safety interlock fill system comprising:
- the onsite CO2 source, said onsite CO2 source comprising a source vessel containing liquefied CO2, and vaporized CO2 in a headspace of the source vessel;
- a fill manifold operably connected to the source vessel, said fill manifold comprising one or more conduits positioned between the source vessel and the container, said one or more conduits comprising at least a CO2 vapor supply conduit extending into the headspace of the source vessel of the onsite CO2 source;
- said fill manifold further comprising at least one pressure transducer situated along the one or more conduits, said CO2 vapor supply conduit of the fill manifold configured to receive a finite amount of the vaporized CO2 during the pressurization and leak checking of the fill manifold, said CO2 vapor supply conduit receiving the vaporized CO2 from the headspace of the source vessel of the onsite CO2 source;
- a controller in communication with the fill manifold and the at least one pressure transducer to automatically perform the leak checking of the fill manifold and the pressurization of the fill manifold, the controller having as a first input a first set point equal to the unallowable reduction in pressure of the vaporized CO2 in the fill manifold during a predetermined time period that the leak checking occurs, and further wherein the controller has a second set point equal to the predetermined lower pressure of the vaporized CO2 in the fill manifold below which dry ice may form and a third set point equal to the predetermined upper pressure of the vaporized CO2 above which reversible flow of CO2 vapor may occur from the container into the fill manifold;
- wherein the controller is configured to receive signals corresponding to real-time pressure measurements from the pressure transducer during the predetermined time period of the leak check and/or the pressurization of the fill manifold;
- said controller configured to prevent the subsequent filling operation when one or more of the real-time pressure measurements (i) has changed in pressure by an amount that is equal to or higher than the first set point of the unallowable reduction in pressure of the vaporized CO2 in the fill manifold, or (ii) the one or more of the real-time pressure measurements is lower than the predetermined lower pressure at which dry ice forms, or (iii) the one or more of the real-time pressure measurements is greater than the predetermined upper pressure at which reversible flow of CO2 vapor may occur from the container into the fill manifold;
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- said controller is configured to allow the subsequent filling operation when each of (i) the one or more of the real-time pressure measurements has change in pressure by an amount that is less than the first set point of the unallowable reduction in pressure of the vaporized CO2 in the manifold, and (ii) the one or more of the real-time pressure measurements is equal to or above the predetermined lower pressure at which dry ice forms, and (iii) the one or more real-time pressure measurements is equal to or lower than the predetermined upper pressure at which reversible flow of CO2 vapor may occur from the container into the fill manifold.