Abstract: Sealable container assemblies include containers for materials which are to be microwave heated, such as in digesting or extracting operations, made of thermoplastic material, such as fluoropolymer, that is strengthened by reinforcing means that may be a fiber reinforced thermoplastic of high tensile strength, such as polyetherimide, with reinforcing continuous fibers in a matrix of such thermoplastic, which fibers are very preferably in the shape of a sleeve or sleeves and are of glass or other heat resistant and microwave transmissive material. The containers may be strengthened by incorporating the fiber reinforced thermoplastic in a wall or walls of the container or preferably by inserting the container into a reinforcement, which is a sleeve or collar of the reinforced thermoplastic. In both such constructions the reinforcing means protects the container against radial failure due to pressure that is generated by the microwave heating of the container contents.

Abstract: A process for manufacturing containers that are suitable for containing materials that are to be heated by microwave radiation or other heating equipment includes making a dilute liquid dispersion of quartz and/or glass fibers (very preferably microfibers), depositing them on the interior of a permeable female mold or form, from the dispersion by way of a pressure differential across the female mold, with the liquid passing through the mold, moving a male mold or form which matches the female mold, into and against the container in the female mold, terminating the pressure differential across the female mold, applying a pressure differential across the male mold to release the container from the female mold and press it against the male mold exterior, withdrawing the male mold, with the container held to it, releasing the container from the male mold and sintering the container, to make it form retaining.

Abstract: An explosion proof microwave heated solvent extraction apparatus or system for extracting organic materials includes a pressure resistant microwave transmissive extraction container, which is preferably of reinforced polyetherimide lined with fluoropolymer, in a microwave radiation heated chamber, with a device for controlling a microwave radiation generator, such as a magnetron, in response to the presence of any solvent vapor in a collection container for rupture diaphragm discharged material from an extraction container or in exhaust gas from the chamber. The presence of the solvent in the collection container or exhaust gas is preferably detected by a semiconductor gas sensor which decreases its electrical resistance in the presence of solvent vapors, thereby increasing its voltage and thus controlling operation of the magnetron, turning it off when solvent vapor (and a potentially explosive gas mixture) is present.

Abstract: A process for manufacturing containers for holding heated materials includes the steps of depositing a dispersion of fibers in a liquid onto the interior of a liquid permeable female mold, removing liquid from the deposited dispersion by applying a pressure differential across the mold, with the higher pressure being in the interior of the mold, moving a liquid permeable male mold into the female mold, terminating the pressure differential across the female mold, applying a pressure differential across the male mold, with the higher pressure being on the exterior thereof, to press the container onto the male mold exterior, withdrawing the male mold from the female mold, with the container being held to the male mold, and releasing the container from the male mold.

Abstract: Containers for materials which are to be microwave heated such as in digesting or extracting operations, are made of thermoplastic material, such as a fluoropolymer, e.g., TEFLON.RTM. PFA, that is strengthened by reinforcing means that may be a fiber reinforced thermoplastic of high tensile strength, such as polyetherimide, e.g., ULTEM.RTM., with reinforcing continuous fibers in a matrix of such thermoplastic, which fibers are preferably of glass or other heat resistant and microwave transmissive material. The containers may be strengthened by incorporating the fiber reinforced thermoplastic in a wall or walls of the container or by inserting the container into a reinforcement, which is a sleeve or collar of the reinforced thermoplastic. In both such constructions the reinforcing means protects the container against peripheral or radial failure due to pressure that is generated by the microwave heating of the container contents.

Abstract: A process and apparatus for controlled continuous microwave digestion of samples of materials to prepare them for subsequent analyses or other chemical operations. The material to be analyzed, in finely divided form and mixed with digesting liquid, such as a strong acid, is charged as a slug into a flowing liquid carrier stream, usually water, which stream, containing the slug, is passed in a tube through a zone in which the tube and contents are subjected to microwave radiation, to heat the digesting liquid and the material to be digested to promote the digestion. The process and apparatus are modified by inclusion of detecting and controlling steps and corresponding apparatus components to detect a condition of the flowing liquid without physically contacting it, as by determining the dielectric constant of contents of the tube, or a related property of such contents at one or more locations of the tube, usually outside the microwave zone, and controlling operations of the process and apparatus accordingly.

Abstract: A highly preferred container for ashable material, which material is to be ashed by heat in an ashing furnace, while it is in such container, especially when such container is to be heated by microwave radiation onto microwave absorptive elements of the furnace, which thereby heat the container, is a heat resistant, walled container which is light weight, microwave transmissive, porous and air transmissive, which is of quartz microfibers that are held in desired walled container form, preferably in substantially flat cylindrical form. Such a container may be made by shaping a heat resistant, light weight, microwave transmissive and porous non-woven sheet of quartz microfibers to container form and heating and curing such sheet in such form, preferably after moistening it with water, whereby a form-retaining container results that can be successfully employed to hold ashable samples to be ashed for analysis during microwave powered ashings of such samples.

Abstract: A ventable container for materials to be heated (preferably digested) by microwave radiation includes a movable rupture diaphragm in a venting passageway in a closure or cover for such container. Such diaphragm is tightenable into place so that the container is sealed and in such sealed state is protected by the rupture diaphragm against pressures that could develop in the container that are higher than that for which it was designed. An important feature of the invention is that the rupture diaphragm is controllably movable, when desired, to open positions to vent the container during heating and afterward, and is resealable after venting. Because of the chemical reactivity of the reagents utilized in digestions an inner chemically resistant liner is desirably employed in conjunction with a physically stronger outer body, with the outer body giving the liner enough strength to withstand pressures developed during the heating.

Abstract: A process for rapidly sterilizing biological media, such as broths and gels used as incubation or growth media to test the presence of microorganisms, such as bacteria, includes applying microwave radiation to such an aqueous biological medium contained in a microwave transmissive pressure retaining container, such as a capped cylinder made of polytetrafluoroethylene, which cap is preferably equipped with ports, by directing the microwave radiation through the container and onto the medium in such amount that the pressure in the container and the temperature of the medium are raised above ambient pressure and temperature, and maintaining such raised pressure and temperature for a time sufficient to sterilize the medium.

Abstract: An apparatus for use in analyzing materials for ash content includes a walled chamber which retains microwave radiation therein, a source of microwave radiation, such as a magnetron, for radiating onto contents of such chamber, and an ashing furnace in the chamber which includes a heat resistant wall of low thermal conductivity, which is transmissive of microwave radiation, and a microwave absorptive material which is capable of being heated by microwave radiation to an ashing temperature. The furnace includes a passageway through it for the entry into the furnace cavity of a gas, such as air, and for venting gas, such as combustion products, from the furnace cavity, and preferably also includes a removable trapezoidally shaped door in a front wall thereof, which, when the chamber door is open, is readily removable from the furnace by hand, without burning the operator's fingers, despite the high internal temperature in the furnace cavity.

Abstract: A process for manufacturing containers that are suitable for containing materials that are to be heated by microwave radiation or other heating means includes making a dilute liquid dispersion of quartz and/or glass fibers (very preferably microfibers), depositing them on the interior of a permeable female mold or form, from the dispersion by means of a pressure differential across the female mold, with the liquid passing through the mold, moving a male mold or form which matches the female mold, into and against the container in the female mold, terminating the pressure differential across the female mold, applying a pressure differential across the male mold to release the container from the female mold and press it against the male mold exterior, withdrawing the male mold, with the container held to it, releasing the container from the male mold and sintering the container, to make it form retaining.

Abstract: A ventable container for materials to be heated (preferably digested) by microwave radiation includes a movable rupture diaphragm in a venting passageway in a closure or cover for such container. Such diaphragm is tightenable into place so that the container is sealed and in such sealed state is protected by the rupture diaphragm against pressures that could develop in the container that are higher than that for which it was designed. An important feature of the invention is that the rupture diaphragm is controllably movable, when desired, to open positions to vent the container during heating and afterward, and is resealable after such venting. Because of the chemical reactivity of the reagents utilized in digestions an inner chemically resistant liner is desirably employed in conjunction with a physically stronger outer body, with the outer body giving the liner enough strength to withstand pressures developed during the heating.

Abstract: A continuous flow microwave heated digesting system, which is especially useful for digesting samples of materials to be analyzed with an atomic absorption spectrometer (ASS), includes a chamber, a source of microwave radiation into the chamber, thin bore chemical resistant an microwave transmissive tubing within the chamber onto which the microwave radiation impinges to heat contents of the tubing, and a pump or other suitable apparatus or device for passing through the tubing the sample of material to be digested, dispersed in a digesting medium for it, which sample in the digesting medium is in the form of a discrete slug in a carrier liquid. A suitable device is provided for inserting into the carrier liquid, which is usually water, the slug of material to be digested in the digesting liquid and a backpressure controller is also provided to control backpressure on the slug and the carrier liquid n the tubing.

Abstract: A microwave heating system which is especially useful for rapidly, uniformly and positively sterlizing biological media, such as broths and gels used as incubation or growth media for bacteria, includes a source of microwave radiation, a microwave chamber, a container or a plurality of containers in the chamber, and a mixer for mixing the contents of the container or containers during heating. The mixer is at least partially external to the container and is capable of operating when the container is positively sealed to prevent contamination of the contents, and the mixer is preferably a combination of an external magnet and a mixing element which is at least in part of magnetic material and is moved by changes in the magnetic field set up by the magnet, as the container and contained mixing element are moved with respect to the magnet, as on an oscillating turntable.

Abstract: A process for rapidly sterilizing biological media, such as broths and gels used as incubation or growth media to test the presence of microorganisms, such as bacteria, includes applying microwave radiation to such an aqueous biological medium contained in a microwave transmissive pressure retaining container, such as a capped cylinder made of polytetrafluoroethylene, which cap is preferably equipped with ports, by directing the microwave radiation responsive to container pressure through the container and onto the medium in such amount that the pressure in the container and the temperature of the medium are raised above ambient pressure and temperature, and maintaining such raised pressure and temperature for a short time, usually less than ten minutes, which is sufficient to sterilize the medium.

Abstract: A container for an ashable material, to be ashed by heat in an ashing furnace, especially one heated by microwave radiation onto microwave absorptive elements thereof, comprises a heat resistant, walled container which is light weight, microwave transmissive and porous, and which is of quartz microfibers that are held in desired walled container form, preferably in substantially flat cylindrical form. Such a container is made by shaping a heat resistant, light weight, microwave transmissive and porous non-woven sheet of quartz microfibers to container form and heating and curing such sheet in such form, preferably after moistening it with water, whereby a form-retaining container results that can be successfully employed to hold ashable analytic samples during ashings thereof.

Abstract: A microwave oven particularly suitable for laboratory analytical use is described. The oven is designed for chemical digestion and the drying of materials to very low moisture levels. The oven utilizes a rotating platform to move the material being subjected to microwave radiation through the oven chamber to ensure uniform contact of the microwaves with the material. Radiation mixers and radiation isolators are also used to disperse radiation in the oven and absorb excess radiation.

Abstract: An apparatus and method for quantitatively measuring volatiles, solids and solvent extractables is described which provides rapid and accurate determinations using microwave heating, electronic balance weighing and solvent extracting of solubles. The method involves subjecting a weighed sample to microwave drying for a preselected time, reweighing to obtain the dry weight and determine volatile loss, solvent extracting the dried sample to determine fats, oils and other extractables followed by final measurement of residual solids. The apparatus is preferably automated to sequentially actuate the required weighing, microwave heating, solvent extraction, redrying, reweighing and calculation of the percentages of volatiles, solvent solubles and solids. The apparatus and method are particularly suited for analytical uses in the food and dairy industries.

Abstract: A liquid dishwashing detergent composition for hand washing of dishes in cold water includes a synthetic organic nonionic detergent, a cationic surface active agent, a water soluble C.sub.21 dicarboxylic salt and an aqueous medium. The proportion of the combination of nonionic detergent and cationic surface active agent is a detersive proportion, useful to remove fatty deposits on dishes, and the proportion of the C.sub.21 dicarboxylic salt is sufficient to improve the detersive action in cold water of the combination of nonionic detergent and cationic surfactant so that the composition better removes fatty deposits on dishes being washed.

Abstract: A microwave oven particularly suitable for laboratory analytical use is described. The oven is designed for chemical digestion and the drying of materials to very low moisture levels. The oven utilizes a rotating platform to move the material being subjected to microwave radiation through the oven chamber to ensure uniform contact of the microwaves with the material. Radiation mixers and radiation isolators are also used to disperse radiation in the oven and absorb excess radiation.