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US 5,620,659 AGranted
Apparatus for preventing explosions during microwave heated solvent extractions
AssigneeCEM Corporation
InventorRobert N. Revesz
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AssigneeCEM Corporation
InventorRobert N. Revesz
Estimating the term…
A process for extracting extractable material from a base material in which it is present, while protecting against explosion of any solvent vapor in air includes heating by microwave radiation in a closed pressure-resistant and heat-resistant container, such base material, extractable material and organic extraction solvent, passing air near or into contact with the extraction container so that it will carry away from the container any escaping solvent vapor, and passing said air with the solvent vapor, if present, into contact with solvent detector which turns off a source of microwave radiation when the solvent vapor is present. Preferably the invented process will include passing the air, with any solvent vapor which may be present in it, to a flow detector, which will turn off the source of microwave radiation if flow ceases. The described processes may also include providing a rupture diaphragm to release extraction container contents at a pressure lower than that at which the container will fail, venting any contents exiting the container on to a collection container and venting vapor contents thereof to a solvent vapor detector. Also described are apparatuses for practicing the mentioned processes.
An explosion proof microwave heated solvent extraction apparatus for extracting materials with an organic extracting solvent which is explosive in air, which apparatus comprises a walled chamber, a source of microwave radiation into said chamber, a microwave transmissive extraction container in said chamber, adapted to contain, under pressure, said organic extracting solvent, base material and extractable material with the base material, which extractable material is extractable by the solvent while the solvent is being heated by the microwave radiation, means for passing air through the chamber in an inlet and out an outlet in the chamber, means for detecting the presence of the solvent in said air leaving the chamber, and for modifying an electrical signal in response to the presence of the solvent in said air, said means comprising a switch that requires manual operation to reactivate the source of microwave radiation, and means for controlling operation of the source of microwave radiation in response to said modified electrical signal so that radiation from said source is terminated when the solvent is detected in the air leaving the chamber at a concentration which is not more than a predetermined explosive concentration.
A microwave heated solvent extraction apparatus for extracting materials with an organic extracting solvent, the vapor of which is explosive in air, which apparatus comprises a walled chamber, a source of microwave radiation into said chamber, a microwave transmissive extraction container in said chamber, adapted to contain, under elevated temperature and pressure, said extracting solvent, base material and extractable material with the base material, an inlet to the chamber and an outlet from the chamber, through which inlet, chamber and outlet air can be passed, means for passing air through said inlet, chamber and outlet past the container so that any said solvent vapor escaping from said container will be carried through the outlet with the air, means for detecting presence of said solvent vapor in said air after they pass through the outlet and for modifying an electrical signal in response to the presence of said solvent vapor in said air, means for controlling operation of the source of microwave radiation in response to said modified electrical signal from said detecting means, means for delivering said modified electrical signal from said detecting means to said controlling means, means for detecting absence of air flow in the apparatus downstream of the chamber and means for shutting down the source of microwave radiation when said absence of air flow is detected by said flow detecting means.
A microwave heated solvent extraction apparatus for extracting materials with an organic extracting solvent, the vapor of which is explosive in air, which apparatus comprises a walled chamber, a source of microwave radiation into said chamber, a microwave transmissive extraction container in said chamber, adapted to contain, under elevated temperature and pressure, said extracting material, base material and extractable material with the base material, which extractable material is extractable by said solvent while said solvent is being heated by said microwave radiation, means for passing air through said chamber in an inlet to and out an outlet from said chamber, means for detecting presence of said solvent in said air leaving said chamber and for modifying an electrical signal in response to said detecting of said solvent in said air, means for controlling operation of said source of microwave radiation in response to said modified electrical signal so that when said solvent is detected by said detector microwave radiation from the source thereof is terminated, and an air flow detector which comprises means for turning off said source of microwave radiation when said air flow ceases, whereby said apparatus is protected against possible explosions when solvent escapes from said extraction container during microwave heating of the contents thereof.
An explosion proof microwave heated solvent extraction apparatus which comprises a source of microwave radiation, a walled chamber into which such microwave radiation is directed, which chamber includes an inlet through which air can enter the chamber and an outlet through which air can exit the chamber, a microwave transmissive extraction container in said chamber, adapted to contain, under pressure, extracting solvent medium and material to be extracted, safety rupture means associated with the extraction container, which rupture means ruptures when the pressure in the container is at a predetermined safe limit and thereby releases solvent vapor from the extraction container, a collection container into which the released solvent vapor and any entrained solvent liquid are directed and in which they are collected, means for passing air into the chamber through the inlet and out of the chamber through the outlet, and a solvent vapor detector constructed and positioned for detecting the presence of solvent vapor from the collection container, which solvent vapor detector controls operation of the source of microwave radiation so as to shut down said source when solvent vapor is detected by said detector at a concentration which is not more than a predetermined explosive concentration.
Dependencies are inferred from the claim text.