Abstract: An improved blast cleaning system and an improved method of blast cleaning using solid carbon dioxide pellets is provided. A compressed air source--preferably an air compressor--is used to produce a compressed air or carrier gas stream which is cooled to the desired temperature by injection of a cryogen--preferably liquid nitrogen--before the solid carbon dioxide pellets are introduced into the carrier gas stream. Solid carbon dioxide pellets are then added to the cooled compressed air stream and then propelled towards the surface to be cleaned. Using a compressed air stream which is precooled to the desired operating temperature helps to minimize the sublimation of the carbon dioxide pellets. The use of the precooled compressed air stream also allows greater control of the hardness, size, density, impact forces, stripping rates, and stripping efficiencies of the carbon dioxide pellets. An improved method of transporting solid carbon dioxide pellets which can be used for nonblasting applications (e.g.

Abstract: A flexible, non-water absorbing insulation system is described for insulating articles exposed to relatively cold temperatures. This insulation system is especially adapted for insulating delivery or transfer hoses used with cryogenic liquid transfer operations. The insulating material is a thermoplastic sheet-like layer having gas-filled cells to which is attached or bonded to a metallized thermoplastic film. In one embodiment, the metallized thermoplastic material is bonded to the smooth side of the thermoplastic sheet-like material. In another embodiment, metallized thermoplastic material is bonded to both sides of the cell-containing thermoplastic material. The sheet-like insulating material is wrapped at least twice around the hose or article to be insulated. Slits may be cut in the insulating material to make the hose self draining whereby any condensed water can gravity drain once the temperature is above the freezing point of water.

Abstract: A flexible, non-water absorbing insulation system is described for insulating articles exposed to relatively cold temperatures. This insulation system is especially adapted for insulating delivery or transfer hoses used with cryogenic liquid transfer operations. The insulating material is a thermoplastic sheet-like layer having gas-filled cells to which is attached or bonded to a metallized thermoplastic film. In one embodiment, the metallized thermoplastic material is bonded to the smooth side of the thermoplastic sheet-like material. In another embodiment, metallized thermoplastic material is bonded to both sides of the cell-containing thermoplastic material. The sheet-like insulating material is wrapped at least twice around the hose or article to be insulated. Slits may be cut in the insulating material to make the hose self draining whereby any condensed water can gravity drain once the temperature is above the freezing point of water.

Abstract: A chiller or tunnel freezer for rapid chilling of chicken carcasses and the like wherein a cryogen such as liquid nitrogen or carbon dioxide snow is sprayed directly on the carcasses or other items as they travel through a passage or tunnel, and wherein vortical flow of air and/or vaporized cryogen is effected within the chiller to continuously sweep the bottom surface of the chiller and recirculate cryogen from the bottom surface, thereby avoiding accumulation of liquid nitrogen or CO.sub.2 snow on the bottom surface. The vortical flow is preferably provided by one or more fans disposed within the tunnel. A deflector may be provided on the tunnel interior to direct recirculated cryogen onto the items being chilled. A damper may be provided to regulate fan output and thereby enable optimization of operational efficiency.

Abstract: A method and apparatus for producing solid carbon dioxide snow blocks comprising a mold having a plurality of separate mold cavities, and a liquid CO.sub.2 manifold providing one or more injection nozzles in each of the mold cavities. A vent/vapor heat exchange with incoming liquid may be employed to improve liquid-to-snow conversion rate. The manifold may take a pressure drop turn at each branch to assure that each nozzle receives an adequate supply of liquid CO.sub.2. Each nozzle may have multiple orifices to assure that the snow is dispersed relatively evenly in each mold cavity. Each of the orifices may be located on a relative high point relative to the manifold to facilitate clearance of dry ice blockages in the manifold. A timer may be used to regulate injection. As an alternative or as a backup, fullness of one or more mold cavities may be detected by a sensor, and means may be provided to discontinue injection when one or more mold cavities have been filled.

Abstract: Fluid transfer apparatus comprising a fluid reservoir and a pump connected to the reservoir by a supply line, wherein the apparatus is configured so that vapor generated in the pump during periods of inoperation may escape from the pump cavity through the pump inlet, rather than being trapped in the pump cavity, and liquid may flow into the pump cavity from the supply line through the pump inlet to replace escaping vapor, thereby providing reliable pump start-up during intermittent operation. The apparatus may be employed to pump LNG for fueling of vehicles. Where LNG or another cryogenic fluid is being pumped, the pump is preferably driven by a motor located above the pump and connected thereto by an elongated shaft. Shaft seals may be provided to prevent the fluid being pumped from contacting the motor or the bearings supporting the motor shaft. A vapor trap may be provided beneath the shaft seals to prevent contact between liquid being pumped and the shaft seals.

Abstract: A protection system for electric motors in refrigerated environments, especially those environments cooled to very low temperatures, includes routing a cryogen coolant through the electric motor. A minimum flow of cryogen coolant is maintained through the motor to prevent ingress of moisture in the motor interior. The arrangement is especially useful with cryogenically cooled refrigeration systems, because the same cryogen coolant used to refrigerate the system can also be used to provide a purging flow of cryogen coolant gas through the electric motor.

Abstract: According to the present invention, apparatus for freezing fragile food products is provided. The apparatus includes a first freezing section which includes a solid conveyor belt which is guided to provide an upper product receiving section and a lower section, which passes through a bath of cryogen so as to chill the surface of the belt. The first freezing section includes means to admit product onto the upper belt section and also includes means to move the product to an exit end of the upper belt section. A second freezing section is provided which is a spiral mechanical or cryogenic freezer. The first freezer has an entry end and an exit end. The entry end of the second freezing section is mated to the exit end of the first freezing section so as to receive product having a bottom frozen surface crust from the first freezing section.

Abstract: A freezer includes a conveyor belt within an enclosure. The conveyor belt is formed in an endless loop with top and bottom runs. Coolant is sprayed underneath the top run, and overspray is accumulated in a coolant bath through which the lower run passes to provide additional cooling.

Abstract: The present invention is directed to apparatus for distribution of cryogen across the width of a conveyor belt. The apparatus includes a housing for receiving cryogen from a distribution manifold mounted axially within the housing. The distribution manifold is in fluid communication with a source of cryogen. The distribution manifold has a plurality of apertures for releasing cryogen into the interior of the housing. The housing has a slot extending across the length of the housing for distribution of a curtain of cryogen onto articles to be frozen.

Abstract: A tunnel freezer uses carbon dioxide snow to directly contact product carried on a conveyor belt passing through the freezer. Fans are provided above and below the upper conveyor belt run carrying the product, with the fans above and below having downwardly directed exhaust. Trough-shaped deflector plates are provided adjacent the lower fans to circulate a flow adjacent the underneath surface of the upper conveyor belt run. Preferably, circulation adjacent the upper conveyor belt run is generally parallel to the upper conveyor belt run, and turning vanes are provided to deflect the flow upwardly through the upper conveyor belt run. Freezers may be provided with one or more cooling zones arranged in series along the path of conveyor belt travel.

Abstract: The present invention is directed to a method for treatment of poultry prior to slaughter of the poultry. In the method, poultry are exposed to a first atmosphere having a carbon dioxide concentration sufficient to induce relaxation of the poultry for a period of time sufficient to effect the relaxation. The relaxed poultry are then immediately exposed to a second atmosphere having a carbon dioxide concentration sufficient to render the poultry unconscious. The poultry are subjected to the second atmosphere for a period of time sufficient to effect the unconsciousness, but not sufficient to kill the poultry by being exposed to the second carbon dioxide atmosphere. The poultry are then slaughtered prior to the poultry regaining consciousness.

Abstract: Fluid transfer apparatus comprising a fluid reservoir and a pump connected to the reservoir by a supply line, wherein the apparatus is configured so that vapor generated in the pump during periods of inoperation may escape from the pump cavity through the pump inlet, rather than being trapped in the pump cavity, and liquid may flow into the pump cavity from the supply line through the pump inlet to replace escaping vapor, thereby providing reliable pump start-up during intermittent operation. The apparatus may be employed to pump LNG for fueling of vehicles. Where LNG or another cryogenic fluid is being pumped, the pump is preferably driven by a motor located above the pump and connected thereto by an elongated shaft. Shaft seals may be provided to prevent the fluid being pumped from contacting the motor or the bearings supporting the motor shaft. A vapor trap may be provided beneath the shaft seals to prevent contact between liquid being pumped and the shaft seals.

Abstract: The present invention is directed to a process for purifying natural gas to provide a liquified natural gas product which is substantially pure methane. In the process, a natural gas feed stream is introduced into indirect countercurrent heat exchange in a first heat exchanger to cool the natural gas to below the dew point of ethane and higher hydrocarbons so as to separate the feed stream into a gas which is substantially pure methane and liquid which contains the ethane and higher hydrocarbons. The liquid/gas mixture is transferred to a separator where the gas occupies the head space of the separator and the liquid occupies the bottom of the separator. A gas fraction is removed from the top of the separator and is introduced into countercurrent heat exchange with liquid nitrogen in a second heat exchanger so as to liquefy the substantially pure methane gas.

Abstract: A method is disclosed for the reduction of emissions of solvent vapors from a batch mixing vessel by cryogenically condensing such vapors in and adjacent the top loading hatch at a rate approximating their evaporation from the mix.

Abstract: The present invention is directed to a coupling assembly for dispensing cryogenic fluids, The coupling assembly includes an upstream terminus coupled to a source of cryogenic fluid and a downstream terminus connected to a container for receiving the cryogenic fluid. A poppet valve assembly is disposed at the upstream dispensing terminus. This poppet valve assembly is mechanically operated to be opened and closed. A second poppet valve assembly has a downstream terminus which is coupled to a receiving tank for the cryogenic fluid and an upstream terminus for coupling with the first poppet valve assembly. The second poppet valve assembly is opened and closed through overcoming the pressure of a spring by the pressure of the cryogenic fluid being transferred and the release of the cryogenic fluid pressure, A threaded wheel mounted on the first poppet valve assembly mates with a threaded portion on the second poppet valve assembly to connect and disconnect the two parts of the coupling.

Abstract: The present invention is directed to a process for increasing the methane content of liquid natural gas to provide an essentially pure liquid methane product. In the process, a liquid natural gas feed stream is introduced into a first heat exchanger in indirect heat exchange with a purified methane vapor stream so as to liquify the purified methane vapor stream and to provide a purified liquid methane product. The heat exchange results in increasing the temperature of the liquid natural gas feed stream to a temperature just below the dew point of the liquid natural gas feed stream so as to partially vaporize the liquid natural gas feed stream to provide a mixture of a major amount of substantially pure methane vapor and a minor amount of liquid containing methane and higher hydrocarbons. The mixture of vapor and liquid from the first heat exchanger is transferred to a low pressure separator to provide a liquid bottom fraction and a purified methane top vapor fraction.

Abstract: The present invention is directed to a method for increasing the capacity of a sewage treatment plant. In the method, oxygen is injected into the recycle sludge stream from the settling tank prior to introducing the recycle sludge stream into the secondary waste water treatment tank.

Abstract: A food freezer for continuous freezing of food products utilizing a helical conveyor for transporting the food products through an enclosure in which the food products are cooled. Mechanical refrigeration apparatus employs a refrigerant to cool an atmosphere gas which is circulated across the food products within the enclosure. The refrigerant is also employed to subcool a cryogen which also cools the same food products.

Abstract: The present invention is directed to a method for dispensing a sterilizing gas. In the method, a liquid mixture of ethylene oxide and carbon dioxide is provided. A cylinder is partially filled with the liquid mixture of ethylene oxide and carbon dioxide. The head space of the cylinder is then pressurized with an inert gas at a pressure substantially higher than the vapor pressure of the liquid mixture of ethylene oxide and carbon dioxide. The liquid gas mixture is then dispensed from the cylinder under conditions whereby the head space pressure is maintained greater than the vapor pressure of the liquid mixture of ethylene oxide and carbon dioxide.