Air Products and Chemicals, Inc.

Klee, David J.

David J Klee

Thomas W Burke

Edward F Kiczek

Earl W Moore

Peter C Nelson

Joseph Perry Cohen

Roger A Howells

David R Ruprecht

Kevin S McAfee

John F Boyle

Norris G Lovette

John C Mullane, Jr

Robert J Shaw

Donald J Ehnot

Jack H Godtfring

Scott A Miller

Method and apparatus for controlling removal of gaseous cryogen from a continuous tunnel type freezer wherein the cryogen and product to be frozen travel in counterflow heat exchange relation to minimize ambient atmosphere moving into the tunnel and out of the exhaust system with the exhausted gaseous cryogen.

Exhaust system for a cryogenic freezer

The present invention is a tunnel freezer which incorporates a 'dual flow' design whereby the refrigerant is introduced at each end of the tunnel and withdrawn from the middle of the tunnel. A key to the present invention is that the dual flow design allows one to confine the pressure gradient for leaks between the ends of the tunnel where it will not be a concern since the item entrance and exit ports (which ports provide a ready access for leaks) are located at the ends of the tunnel.

Dual flow tunnel freezer

A spiral type freezer constructed and operated to introduce refrigerated atmosphere into the bottom of the insulated chamber and circulate the atmosphere in a circulation flow from the bottom of the chamber to an exit on top of the chamber, the refrigerated atmosphere producing a thermal gradient from the bottom to the top of the chamber so that the freezer is operated non-isothermally.

Spiral freezer

Improving the connective heat transfer of a tunnel type cryogenic freezer by positioning the circulating fan blades upside down and closer to the articles moving through the tunnel.

Convective heat transfer system for a cryogenic freezer

Method and apparatus for controlling the cooldown and steady-state operation of a tunnel type cryogenic freezer by providing auxiliary cryogen to one or more gas recirculating zones of the freezer and controlling the supply of the auxiliary cryogen by sensing the temperature of the gas recirculating zone and comparing the temperature to a pre-set level.

Cryogenic freezer control

A method and apparatus for controlling movement of the refrigerated atmosphere (e.g. gaseous cryogen) contained inside the insulated chamber of a spiral type freezer out of, or ambient atmosphere into, the lower opening of the freezer by establishing a positive pressure of ambient atmosphere adjacent the inlet opening of the freezer.

Spiral cryogenic freezer

Method and apparatus for controlling gaseous cryogen flow through a continuous tunnel type freezer wherein the cryogen and product to be frozen travel in counterflow heat exchange relation to minimize egress of cryogen from, or ingress of ambient air into the product discharge opening in the freezer.

Method and apparatus for gas flow control in a cryogenic freezer

A process and apparatus are set forth for a refrigerating or freezing system wherein liquid cryogen, such as liquid air, is fully vaporized during use to avoid dangers of liquid cryogen pooling, liquid cryogen contact with apparatus surfaces or inadvertent oxygen enrichment.

Cryogenic forced convection refrigerating system

In the blasting of articles with impact media, the mixture of used media and fragments of material thereby removed from said articles fall to the bottom of the thermally insulated treating chamber. A method is disclosed for discharging such mixture through an opening in the bottom of the chamber, utilizing a rotating sweeping device having a plurality of sweep arms extending outwardly from a central hub each of the arms being formed of segments to approximate the shape of an ogee curve. Heat leakage into the chamber is minimized by driving the sweeping device from below the bottom of the chamber by an enclosed shaft passed through the insulated bottom of the chamber.

Discharge of blasting media from a treating chamber

Operation of processes for removal of adherent coatings from articles by cryogenic embrittlement of the coatings and blasting of the embrittled coatings with impact media impelled by one or more rotating throwing wheels in a closed treating chamber are disclosed, wherein the chamber is initially cooled down progressively to a supercold preset temperature level considerably below that required for embrittlement of the coatings. In a preferred batch operation the throwing wheel or wheels are rotated in the absence of media fed thereto during an initial stage of the operating cycle. The supercold preset temperature level is controllably maintained for a prefixed time period for prechilling the coated articles. At the end of said prechilling preset time period the blasting of the coated articles is initiated. The blasting is continued for a fixed time period; during part of said blasting time period the temperature of the chamber is permitted to rise to a second preset level and while continuing the blasting the introduction of refrigerant into the vessel is discontinued.

Process control for cryogenic decoating

A cooling and or freezing tunnel is described having a toggle linkage and a pressurized fluid drive to open and close a plurality of openable sections of the tunnel for access and cleaning of the interior. The toggle linkages provide more accurate and reliable movement than the prior art means for opening such tunnels.

Pressurized fluid lift system for a cryogenic freezer

An exhaust system for a cryogenic freezer is set forth wherein the system senses the temperature of an aperture in the freezer to detect any outward passage of cryogenic vapors and based upon that sensing, controllably operates an exhaust fan to remove such cryogenic vapors.

Exhaust control for cryogenic freezer

Novel construction is disclosed for a thermally insulated chamber for batch treatment of materials therein at low temperature wherein frequent opening and closing of the outer door of the chamber is practiced. The chamber walls as well as the insulated outer door of the chamber are constructed of rigid but relatively light metallic frames which remain at near ambient temperature. These frames are covered by sheet metal linings on their outer faces and by a plurality of abutting sheet metal inner liners spaced from the outer liners, the space therebetween being filled with insulating material. Buckling and warping of the walls and door as a result of shrinkage is avoided by limiting the maximum linear dimension of each inner liner, by provision of flexible expansion joints in the inner surface and flexible support members which attach the linings to the basic framework, so arranged that paths of only low thermal conductance occur. The designed chambers are especially useful for removal of coatings on material at cryogenic temperature by contacting the chilled material with a high velocity stream of impact medium. An inner door is provided to close the doorway when the outer door is opened.

Thermally insulated chamber

A method is provided for overcoming problems heretofore encountered in systems for continuous cryogenic deflashing of molded articles. Such previous problems include the cracking of the articles as a result of thermal shock suffered by spraying the liquefied gas coolant directly on the article to effect embrittlement of the flash and that of blasting media sticking to the articles. The now disclosed system avoids thermal shock by more gradual cooling of the article and by effecting the desired embrittlement by contact with gaseous coolant obtained by vaporization of the liquefied gas within the treating chamber prior to its contact with the articles. The arrangement of the spray nozzles for the coolant is designed to provide an adequate precooling period to avoid thermal shock and to obtain a temperature profile such that insufficient cooling of the mold release wax is avoided.

Continuous deflashing system

In the blasting of articles with impact media, the mixture of used media and fragments of material thereby removed from said articles fall to the bottom of the thermally insulated treating chamber. Novel structure is herein disclosed for discharging such mixture through an opening in the bottom of the chamber, utilizing a rotating sweeping device having a plurality of sweep arms extending outwardly from a central hub each of the arms being formed of segments to approximate the shape of an ogee curve. Heat leakage into the chamber is minimized by driving the sweeping device from below the bottom of the chamber by an enclosed shaft passed through the insulated bottom of the chamber.

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Emmaus, PA, United States of America

David J Klee