Abstract: In the processing of an item, particularly a food item, where the final equalized temperature is important to the processing a method and apparatus for predicting the equalized temperature is disclosed. A series of infrared sensors is used to measure the rate of change of the surface temperature of an item after the item is exposed to a known thermal shock such as heating or cooling. The predicted equalized temperature can be calculated from the series of surface temperatures using least squares, non-linear regression techniques. One means for applying a thermal shock to an item would be the use of cryogens such as liquid nitrogen, carbon dixoide snow or synthetic liquid air (SLA).

Abstract: In cooler used for coating a product such as food with a uniform layer of a liquid coating material, the mass of the product is measured either in the cooling chamber or just before it is introduced into the cooling chamber; the mass of a liquid cryogen which will suffice, when introduced into the cooling chamber and into contact with the product, to reduce the temperature of the mass of product to a first predetermined temperature below the melting point temperature of the coating material is calculated; the introduction of the calculated mass of liquid cryogen into the cooling chamber is controlled and the product is thereby cooled to the first predetermined temperature prior to application of a predetermined mass of coating material onto the cooled product to provide a coating thereon.

Abstract: Systems and methods are disclosed for determining heat transfer in an environment. In one system, heat transfer is determined with a probe including at least one element, a power supply, an amplifier, a temperature monitor, a timing structure, and a system controller. In another system, heat transfer is determined with a temperature sampler. In yet another system, the heat transfer rate is controlled in at least a partially closed environment. The disclosed methods include a method for calculating heat transfer from a first predetermined temperature, a second predetermined temperature, measured time and temperature of the environment. In another method, heat transfer is calculated from a first determined temperature, a second measured temperature, a predetermined period of time, and temperature of the environment.

Abstract: Apparatus and methods for freezing products, such as food products, in which a breathable liquid cryogen is sprayed onto the products as they are conveyed into the insulated enclosure of a mechanical conveyor freezer. Some of the cryogen vaporized through contact with the products is ducted into the top of the enclosure, and means may be provided for spraying cryogen directly into the freezer enclosure.

Abstract: In cooler used for coating a product such as food with a uniform layer of a liquid coating material, the mass of the product is measured either in the cooling chamber or just before it is introduced into the cooling chamber; the mass of a liquid cryogen which will suffice, when introduced into the cooling chamber and into contact with the product, to reduce the temperature of the mass of product to a first predetermined temperature below the melting point temperature of the coating material is calculated; the introduction of the calculated mass of liquid cryogen into the cooling chamber is controlled and the product is thereby cooled to the first predetermined temperature prior to application of a predetermined mass of coating material onto the cooled product to provide a coating thereon.

Abstract: An sensor for sensing buoyancy force within a liquid mixture stored within a storage tank and an interlock employing the sensor to prevent a respirable cryogenic mixture from being dispensed from the storage tank with an unsafe oxygen content. The sensor has a float adapted to be submerged in the liquid mixture, thereby to exert a buoyancy force referable to the density. The buoyancy force is sensed by a load cell connected to an elongated base element cantilevered from the outlet by a bracket. The mounting of such sensor ensures that the buoyancy force and therefore, the density of the liquid as dispensed will be measured as opposed to liquid density at some other location of the tank. Such sensor can serve in an interlock in which a controller responsive to the load cell and a temperature sensor, also located within the outlet, controls a valve to close the outlet when the mixture has an unsafe oxygen level.

Abstract: A sensor for sensing buoyancy force within a liquid mixture stored within a storage tank and an interlock employing the sensor to prevent a respirable cryogenic mixture from being dispensed from the storage tank with an unsafe oxygen content. The sensor has a float adapted to be submerged in the liquid mixture, thereby to exert a buoyancy force referable to the density. The buoyancy force is sensed by a load cell connected to an elongated base element cantilevered from the outlet by a bracket. The mounting of such sensor ensures that the buoyancy force and therefore, the density of the liquid as dispensed will be measured as opposed to liquid density at some other location of the tank. Such sensor can serve in an interlock in which a controller responsive to the load cell and a temperature sensor, also located within the outlet, controls a valve to close the outlet when the mixture has an unsafe oxygen level.

Abstract: The present invention provides a food freezing apparatus and method in which food is passed through an elongated tube in which it is subjected to both crust and atmospheric freezing before being removed for packing. The crust freezing is facilitated by spraying liquid cryogen onto the outside of the tube at an upstream portion thereof.

Abstract: An apparatus and method for spraying a cryogen in which a heat load is sprayed with a cryogen from one or more spray nozzles within a spray zone. A heat conductive element is positioned below the article and is provided with a surface sized to catch the liquid content of the cryogen that has been oversprayed, thereby to vaporize the overspray through direct heat transfer with the conductive element. In another aspect the present invention provides an apparatus and method in which a flow network a flow of a liquid cryogen is divided into first and second subsidiary streams. The second subsidiary stream is vaporized within a branch of the network and then mixed back into the first subsidiary stream to produce a two phase flow of the cryogen. The cryogen is then sprayed as the two phase flow. The flow rate of the second subsidiary stream can be controlled with a proportional valve to adjust the quality of the cryogen being sprayed so that pooling of overspray on said heat conductive element is inhibited.

Abstract: An apparatus is provided for storing a multi-component cryogenic mixture as a liquid. The multi-component cryogenic mixture of interest contains at least first and second components. The first component is more volatile than the second component and the second component has a bubble point temperature atmosphere pressure, lower than that of the first component at an above atmosphere pressure. A container is provided in the apparatus for storing the cryogenic mixture. An inevitable heat leakage causes a cryogenic mixture to vaporize so that the vapor phase of the mixture is enriched in the first component and the liquid phase in the mixture is enriched in the second component.

Abstract: A liquid dispenser for dispensing liquid cryogen comprises a vessel (10) and a valve/actuator arrangement (16, 18) the valve being positioned within the vessel and operable to obturate or uncover an outlet orifice (14). The actuator (18) being positioned wholly or substantially outside the vessel, but being able to generate a magnetic force within the vessel for moving a magnet on the valve so as to move the valve between open and closed positions.

Abstract: A liquid cryogen dispenser 10 includes a consolidation structure 20 adjacent its outlet 14 for causing gas contained in the liquid to consolidate into bubbles of sufficient buoyancy to cause them to rise to the surface of the liquid rather than be drawn through the outlet 14 where they can disrupt the smooth flow of liquid cryogen therefrom.

Abstract: A substantially U-shaped immersion freezer having an inlet and an outlet and an immersion zone filled with liquid refrigerant. Product to be frozen is passed into the freezer through the inlet and raised by at least one paddle member to the outlet. The resulting frozen product and some liquid refrigerant is then passed out of the outlet to a conveyor having holes provided therein which allow the liquid refrigerant to be drained from the frozen product for recycling back to the inlet side of the freezer.

Abstract: A cooling apparatus comprises a cooling chamber (2), means (4) for introducing liquefied gas or its cold vapor thereinto, an exhaust passage (16) having flow inducing means associated therewith and a heat transfer means (46) associated with said exhaust passage (16) in which the heat transfer means operates to transfer heat from a heat source to the exhaust gas.

Abstract: An apparatus for freezing particulate bodies, comprising a rotary member having a generally horizontal freezing surface, means for dispensing said bodies onto said surface, means for cooling the surface to a freezing temperature and means for collecting said bodies in at least peripherally frozen state from said surface. The particulate bodies may comprise food stuffs, such as prawns or cream, a pharmaceutical, a microbiological culture, or a puree. Liquified carbon dioxide and nitrogen are preferred for cooling.

Abstract: Cooling apparatus comprises a cooling chamber such as a freezing tunnel having a pipeline for introducing liquid nitrogen into it and an exhaust passage for cold nitrogen vapor. The exhaust passage extends through a rotary regenerative heat exchanger. Downstream of the heat exchanger is a fan operable to draw the exhaust gas through the heat exchanger. A second passage extends through the heat exchanger and is arranged for the flow therethrough of relatively warm air, whereby, in operation, the air is able to transfer heat to the exhaust gas in the heat exchanger.

Abstract: A rotary apparatus for purging empty bottles with nitrogen gas includes a rotor from which arms of flexible material radiate. Each arm carries a gas supply lead. The arrangement is that advancing bottles engages the heads and thereby drive the rotor. Valve means is provided whereby each head in turn is placed in communication with a purging gas supply when it reaches a first position and the communication is ended when the head reaches the second position. During its course of travel from the first position to the second position, the head communicates with a respective bottle and the bottle is thereby purged.