Apparatus and method for preparing an evacuated container

Abstract

An apparatus for vacuum sealing a container is disclosed that includes a vacuum chamber in communication with a vacuum source, the vacuum chamber having at least a first port and an internal pressure, a securing device adapted to secure an open end of the container to the first port of the vacuum chamber; and a heating member at least a portion of which is located inside the vacuum chamber, the heating member is adapted to apply heat to a heat-activated sealant material positioned to cover at least the open end of the container.

Description

FIELD OF THE INVENTION

[0001] The invention relates to sealing, or filling and sealing, evacuated containers. Specifically, the invention relates to evacuating, and vacuum sealing evaporator units and evacuating, vacuum filling, and vacuum sealing absorber units in self-refrigerating devices.

BACKGROUND

[0002] Self-refrigerating devices are known in the art. They are designed to provide cooling without resorting to external sources of cooling such as electricity, ice and the like. Conveniently, these devices can be highly portable. They also typically deliver cooling on a single-use basis, and may therefore be disposable.

[0003] There are many foods and beverages that can be stored almost indefinitely at an average ambient temperature of approximately 20° C.-25° C. but that have more favorable properties when cold than when at ambient temperature. Electrically powered refrigeration units can cool these foods and beverages. The use of these units to cool foods and beverages may not always be practical because the units require a source of electricity, are not usually portable, and may not cool foods and beverages quickly.

[0004] Alternatively, phase change materials such as ice can cool foods and beverages. Such phase change materials may not always be available, and may not cool food or beverages sufficiently quickly. Using ice to cool foods or beverages may be undesirable because ice can be stored for only limited times at temperatures above 0° C. Additionally, a beverage can be undesirably diluted by ice that melts while cooling the beverage.

[0005] An alternate method for providing cooled food or beverages on demand is to use portable insulated containers. These containers typically only function to maintain the temperature of the food or beverage placed inside them and usually require ice to achieve a cooling effect. These containers can be bulky and heavier than the food or beverage being cooled, especially when used in conjunction with ice. Moreover, ice may not be readily available when a cooling effect is desired.

[0006] In addition to cooling food and beverages, there are other applications for which portable cooling devices may be desirable. These include: medical applications, such as cooling of tissues or organs, preparing cold compresses, and cryogenically destroying tissues as part of surgical procedures; industrial applications, such as producing cold water or other cold liquids upon demand, preserving biological specimens, cooling protective clothing; and various cosmetic applications. A portable cooling apparatus could have widespread utility in all these areas.

[0007] A method known in the art for providing a cooling effect in a portable device, for example, a beverage can is to evaporate refrigerant in a first chamber and absorb or adsorb the resultant refrigerant vapor in a second chamber. In such a system, liquid refrigerant boils under reduced pressure in the first chamber, absorbing heat from its surroundings. The vapor generated from the boiling liquid is discharged into the second chamber, which contains a desiccant that absorbs the vapor and the heat.

[0008] A particular self-refrigerating device that can be used in conjunction with the present invention includes three basic sections: an evaporator initially containing a refrigerant, an absorber initially containing a desiccant, and a means to prevent the inadvertent flow of refrigerant vapor between the evaporator and the absorber. This flow-preventing means is also adapted to allow the flow of refrigerant vapor between the evaporator and absorber when, for example, the device is in operation. The functional relationships between these sections have been described in U.S. Pat. Nos. 5,197,302 and 5,048,301, which are incorporated by reference in their entirety.

[0009] The inventive techniques, methods, and apparatus described herein may be utilized in the production of, for example, evaporators and absorbers of these self-refrigerating devices.

SUMMARY OF THE INVENTION

[0010] Various embodiments may include one or more of the following features.

[0011] In a first broad aspect, an apparatus is disclosed for vacuum sealing a container. The apparatus includes a vacuum chamber having at least a first port and an internal pressure. The vacuum chamber is in communication with a vacuum source. A securing device is adapted to secure an open end of the container to the first port of the vacuum chamber and a heating member, at least a portion of which is located inside the vacuum chamber, is adapted to apply heat to a heat-activated sealant material positioned to cover at least the open end of the container. The securing device can include a piston assembly adapted to impart a force against the container. The piston assembly may enable mating of the open end of the container to the first port on the vacuum chamber. The apparatus can further include a sealant material feeding device, which may operate automatically, adapted to position the sealant material to cover at least the open end of the container. The apparatus can also include a sealant material cutting member at least a portion of which is located inside the vacuum chamber. The sealant material cutting member may be adapted to cut the sealant material to a size that covers at least the open end of the container. The sealant material cutting member may be mounted to the heating member by a spring-loaded connection and may be adapted to operate automatically. The heating member of the apparatus may include a surface adapted to mate with a portion of the sealant material, and the portion of sealant material may be positioned proximate a surface of the container that at least partially surrounds the open end of the container. The heating member of the apparatus may be adapted to heat the sealant material to a temperature that is between approximately 300° F. and approximately 800° F., and may be further adapted to apply a pressure between approximately 150 pounds per square inch and approximately 600 pounds per square inch to the sealant material. The vacuum source of the apparatus may be adapted to create an internal pressure in the vacuum chamber that is between approximately 1 torr and approximately 60 torr. The apparatus of claim 1 can further include a controller with at least one input terminal and at least one output terminal, at least one sensor, adapted to sense the internal pressure of the vacuum chamber, connected to an input terminal, and at least one actuating device, adapted to actuate the vacuum source, connected to at least one of the output terminals. The controller can be adapted to receive an input signal from the sensor through the input terminal, process the input signal, and transmit an output signal responsive to the input signal through the output terminal and to the actuating device. The controller can be further adapted to cause at least one of the actuating devices to perform at least one action selected from a group consisting of: securing the open end of the container to the port on the vacuum chamber, actuating the vacuum source to create an internal pressure in the vacuum chamber, positioning the sealant material to cover at least the open end of the container, and applying heat and pressure to the sealant material proximate a surface at least partially surrounding the open end of the container.

[0012] In a second broad aspect, an apparatus is disclosed for vacuum sealing and filling a container, including a vacuum chamber, having at least a first port and an internal pressure, in communication with a vacuum source, a securing device adapted to secure an open end of the container to the first port of the vacuum chamber, a heating member, at least a portion of which is located inside the vacuum chamber, the heating member being adapted to apply heat to a heat-activated sealant material positioned to cover at least the open end of the container, and a hollow feed tube at least a portion of which is located inside the vacuum chamber. The heating member can include an internal passage, the hollow feed tube having an open end that can be in communication with the vacuum source and at least a portion of the hollow feed tube passing through the internal passage of the heating member. The hollow feed tube may be adapted to load a material into the container through the open end of the container. The hollow feed tube can include an open end and the hollow feed tube can be positioned so that the open end of the hollow feed tube is isolated from the vacuum source. The open end of the hollow feed tube can also be isolated from the vacuum source by mating it with a recessed sealing area inside the vacuum chamber. The vacuum source can be adapted to create a pressure inside the vacuum chamber that is between approximately 1 millitorr and 1000 millitorr. The securing device can include a piston assembly, which can enable mating of the open end of the container to the first port on the vacuum chamber, adapted to impart a force against the container. The apparatus can also include a sealant material feeding device adapted to position the sealant material to cover at least the open end of the container and which may operate automatically. The apparatus can include a sealant material cutting member at least a portion of which is located inside the vacuum chamber that is adapted to cut the sealant material to a size to cover at least the open end of the container. The sealant material cutting member can be mounted to the heating member by a spring-loaded connection and can also be adapted to operate automatically. The heating member can include a surface adapted to mate with a portion of the sealant material positioned proximate a surface of the container, and the surface may at least partially surrounding the open end of the container. The heating member can be further adapted to heat the sealant material to a temperature that is between approximately 300° F. and 800° F. The heating member can be adapted to apply a pressure between approximately 150 pounds per square inch and 600 pounds per square inch to the sealant material. The vacuum source can be adapted to create a pressure inside the vacuum chamber that is between approximately 1 torr and 60 torr. The apparatus can also include a controller with at least one input terminal and at least one output terminal, at least one sensor connected to the at least one input terminal, at least one of the sensors adapted to sense the internal pressure of the vacuum chamber, and at least one actuating device connected to the at least one output terminal, at least one of the actuating devices adapted to actuate the vacuum source. The controller can be adapted to receive an input signal from one of the sensors through one of the input terminals, process the input signal, and transmit an output signal responsive to the input signal through one of the output terminals to one of the actuating devices. The controller can also the actuating devices to perform at least one action selected from a group consisting of: securing the open end of the container to the port on the vacuum chamber, actuating the vacuum source to create an internal pressure in the vacuum chamber, feeding a material into the container through the open end of the container, positioning the sealant material to cover at least the open end of the container, and applying heat and pressure to the sealant material proximate a surface at least partially surrounding the open end of the container.

[0013] In a third broad aspect, a method of preparing a container is disclosed, including securing an open end of the container to a port on a vacuum chamber, the open end having a surface at least partially surrounding the open end, actuating a vacuum source in communication with the vacuum chamber to at least partially evacuate the vacuum chamber, positioning a sealant material to cover at least the open end of the container and a portion of the surface at least partially surrounding the open end of the container, and attaching the sealant material to the surface at least partially surrounding the open end of the container to cover at least the open end of the container. Securing the open end of the container to the port on the vacuum chamber can include applying a seating force with a movable assembly. Actuating the vacuum source to at least partially evacuate the vacuum chamber may result in a pressure inside the vacuum chamber that is between approximately 1 torr and 60 torr. Actuating the vacuum source to at least partially evacuate the vacuum chamber can result in a pressure inside the vacuum chamber that is between approximately 1 millitorr and 1000 millitorr. Positioning the sealant material can include using an automatic sealant feeding mechanism. Attaching the sealant material can include applying heat and pressure to at least a portion of the sealant material proximate the surface at least partially surrounding the open end of the container. The method can also include introducing a material, for example, a desiccant into the container through the open end of the container before positioning the sealant material. The method can be automatically repeated.

[0014] In still other broad aspects, containers prepared according to the methods described above are disclosed.

[0015] As used herein, the term “heat activated” refers to substances having particular properties that can be activated by heat. The term “partially evacuating” and derivatives of that term refer to applying a pressure to a space lower than a pressure that previously existed in that space. The phrase “in communication with” is used to identify areas between which fluids or vapors can flow freely. The term “spring loaded” refers to any arrangement that utilizes a spring for connecting, securing, or attaching one or more objects to another object.

[0016] The invention is related to inventions described in and claimed by U.S. application Ser. No. 60/121,744—Dispersion of Refrigerant Materials, filed Feb. 26, 1999, U.S. application Ser. No. 60/121,761—Preparation of Refrigerant Materials, filed on Feb. 26, 1999, and U.S. application Ser. No. 60/121,762 Preparation of Heat Sink Materials, filed Feb. 26, 1999, which are incorporated by reference in their entirety.

[0017] All publications, patent applications, patents, and other references mentioned herein are incorporated by reference in their entirety. In case of conflict, the present specification will control. In addition, the apparatus, methods, and techniques described herein are illustrative only and are not intended to be limiting. Other features and advantages of the invention will be apparent from the following detailed description and from the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

[0018] FIG. 1 is a schematic representation of a self-refrigerating device.

[0019] FIGS. 2A and 2B are an elevation view and a partial elevation view of a vacuum sealing apparatus according to a particular embodiment of the invention.

[0020] FIGS. 3A and 3B are alternate views of a portion of a vacuum sealing apparatus according to a particular embodiment of the invention.

[0021] FIG. 4 is an elevation view of a portion of a vacuum sealing apparatus according to a particular embodiment of the invention.

[0022] FIG. 5 is a flowchart according to a particular embodiment of the invention.

[0023] FIG. 6 is an elevation view of a vacuum filling and sealing apparatus according to a particular embodiment of the invention.

[0024] FIG. 7 is a partial elevation view of a vacuum filling and sealing apparatus according to a particular embodiment of the invention.

[0025] FIG. 8 is a partial elevation view of a vacuum filling and sealing apparatus according to a particular embodiment of the invention.

[0026] FIG. 9 is a flowchart according to a particular embodiment of the invention.

[0027] FIG. 10 is a vacuum filling and sealing apparatus with an automated control system according to a particular embodiment of the invention.

DETAILED DESCRIPTION

[0028] FIG. 1 is a schematic representation of an example of a refrigeration device 20 that may be produced by employing the techniques, methods, and apparatus described herein. Product 22, which is to be cooled, is in thermal contact with evaporator 24. Evaporator 24 comprises a chamber within which evaporation of a refrigerant takes place. This preferably involves desorption of a refrigerant from inner surface 28 of evaporator 24 during the operation of the device. Before the device is activated, the refrigerant is present in evaporator 24, in both a liquid and, less desirably, in a vapor state.

[0029] In the particular embodiment shown in FIG. 1, the desorption process is driven by a pressure differential which is manifested when flow-preventing device 26 is activated. Activation of device 26 permits refrigerant vapor to flow from evaporator 24 to absorber 32. As desorption takes place from the refrigerant on inner surface 28 of evaporator 24, outer surface 30 of evaporator 24 becomes cold. This, in turn cools product 22 that is in thermal contact with outer surface 30 of evaporator 24.

[0030] Absorber 32 includes desiccant 34 distributed throughout its interior. Heat sink 38 is also shown. Upon activation of flow-preventing device 26, evaporating refrigerant moves from evaporator 24 into absorber 32 carrying heat. This heat is deposited into finite capacity desiccant 34 and further transferred to finite capacity heat sink 38.

[0031] Evaporator 24 and absorber 32 may be manufactured independently. The two components may then be mated to each other to create a finished assembly. Generally, independent manufacturing of an evaporator 24 requires evacuating the space inside the evaporator and sealing the evacuated space. Independent manufacturing of an absorber 32 requires evacuating the space inside the absorber, inserting a desiccant 34, and sealing the evacuated and filled space. The techniques, methods, and apparatus described herein may be used to accomplish these tasks.

[0032] Actual physical embodiments of the refrigeration device 20 may include elements that differ from what is represented in FIG. 1. For example, the internal passages and shape of evaporator 24 and absorber 32 may differ. Absorber 32 may not be completely filled with desiccant 34, and various types of desiccant 34 may be used. Flow preventing means 26 may be actuated in any suitable manner. Various types of refrigerant may be used in refrigeration device 20.

[0033] Referring to FIGS. 2A and 2B, a particular embodiment of a vacuum sealing apparatus 50 is shown. Beverage can assembly 72 having bottom surface 73 and integral evaporator 24 is mounted in vacuum sealing apparatus 50. Assembly 72, and evaporator 24 are mounted in the apparatus upside down. However, any convenient orientation can be used. Alternatively, evaporator 24 may be mounted in vacuum sealing apparatus 50 without a corresponding beverage can assembly 72.

[0034] Vacuum sealing apparatus 50 includes vertical frames 52 and 54, horizontal top end frame 56, horizontal center frame 58 and horizontal bottom end frame 60. Frames 52, 54, 56, 58 and 60 are connected together in a manner intended to provide structural support for the other components of vacuum sealing apparatus 50. The arrangement of structural support members is not critical and other arrangements will be apparent to persons skilled in the art.

[0035] Support piston assembly 62 is mounted on bottom end frame 60. Support piston assembly 62 is a moveable, heavy piston assembly designed to support evaporator 24 and beverage can assembly 72 in place, as shown in FIGS. 2A and 2B. Support piston assembly 62 includes support piston 63, support piston cylinder 61 and support piston shaft 65. Support piston shaft 65 and support piston 63 translate axially, which in the depicted embodiment is up and down. Support piston shaft 65 and support piston 63 are illustrated in the raised position. Evaporator 24 and beverage can assembly 72 are removably inserted into vacuum sealing apparatus 50 when support piston shaft 65 and support piston 63 are in a lowered position.

[0036] Support piston shaft 65 and support piston 63 can be driven by any convenient means, for example, by pneumatic actuation. Forcing compressed air into the space underneath support piston 63 inside support piston cylinder 61 causes support piston shaft 65 and support piston 63 to move in an engaging direction, in this embodiment upwardly. Conversely, releasing compressed air from the space underneath support piston 63 inside support piston cylinder 61 allows support piston shaft 65 and support piston 63 to move in a downward direction. When support piston shaft 65 and support piston 63 are raised, evaporator 24 and beverage can assembly 72 are held securely in place inside vacuum sealing apparatus 50. The positions of support piston shaft 65 and support piston 63 can be adjusted either manually, by using support piston position controller 122, or automatically. The support piston may be designed to operate using a different actuating medium, such as, hydraulics, or electricity.

[0037] Lower alignment coupling 64 is mounted on support piston shaft 65. Lower alignment coupling 64 is optionally and desirably adapted to mate with a recess in evaporator support plug 74. Evaporator support plug 74 is optionally and desirably adapted to fit snugly into the contours of evaporator 24.

[0038] Evaporator 24 is secured to beverage can assembly 72. Any convenient method can be used to secure the evaporator 24. For example, evaporator 24 may be welded to beverage can assembly 72 or it may be secured with an adhesive material. Bottom 73 of beverage can assembly 72 includes a hole. This hole lines up with another hole in evaporator 24 when the latter is secured in place thereby creating an opening 75 at the bottom of beverage can assembly 72 into the interior of evaporator 24.

[0039] Vacuum sealing apparatus 50 includes vacuum chamber 80 in communication with vacuum source 85. Upper flange 82, lower flange 70, viewing cylinder 76, and implosion shield 78 enclose vacuum chamber 80. Upper flange 82 is mounted to horizontal center frame 58. Viewing cylinder 76 and implosion shield 78 mate with both upper flange 82 and lower flange 70. Vacuum source 85 may include any convenient device capable of creating a low pressure in vacuum chamber 80, for example, a vacuum pump or a device implementing a venturi effect.

[0040] Viewing cylinder 76 and implosion shield 78 may be constructed, if desired, so that at least a portion of each is substantially transparent to permit an operator to inspect operations inside vacuum chamber 80. The size of vacuum chamber 80 may be smaller than the one illustrated in FIG. 2. A small vacuum chamber 80 is desirable because less volume requires shorter pump-down times during evacuation.

[0041] Beverage can assembly 72 is mated to lower surface 68 of lower vacuum chamber flange 70. Beverage can assembly 72 is arranged so that air and vapor might flow freely from the inside of the evaporator 24, through bottom opening 75 and port 77 in lower vacuum chamber flange 70 to vacuum chamber 80. Beverage can assembly 72 and lower surface 68 form an airtight seal at their mating surface. A ring base edge on bottom 73 of the beverage can assembly 72 can mate directly with lower surface 68. Alternatively, inserting either a flat gasket or an o-ring between a sloped face on bottom 73 of beverage can assembly 72 and lower surface 68 might provide an airtight seal.

[0042] Referring to FIGS. 3A and 3B, upper flange 82 is typically adapted to include several ports 83A, 83B . . . 83K that connect the inside of vacuum chamber 80 to the outside. Ports 83A, 83B . . . 83K might be adapted to provide connections to, for example, a vacuum source, a low pressure vacuum gauge, and a high pressure vacuum gauge or any other connection that might need to pass into vacuum chamber 80. Passage 92 is also provided in upper vacuum chamber flange 82 through which sealer assembly shaft 96 can pass.

[0043] Referring again to FIGS. 2A and 2B, sealer assembly 94 includes shaft 96, heatable sealing head 98, removable shaft coupling end 100, and holes 102 for thermocouple leads, cartridge heater leads, and an optional cooling tube. Sealer assembly 94 is connected by means of upper alignment coupling 114 to sealer head drive piston assembly 116 and is axially translatable, which is up or down as illustrated. Sealer assembly 94 is illustrated in a lowered position. Heatable sealing head 98 may be any convenient type of heating member. In the position shown, sealer head 98 passes through port 77 in lower vacuum chamber flange 70 and applies heat and force directly to sealant material 139 on an area surrounding opening 75 in bottom 73 of beverage can assembly 72. Sealant material 139 can be positioned over at least opening 75 by sealant feeding device 138.

[0044] Sealant material 139 is desirably metallic foil with a heat activated adhesive on one side that can secure sealant material 139 to the area surrounding opening 75 in bottom 73 of beverage can assembly 72. Sealant material 139 may be, for example, aluminum, aluminized Mylar, or copper. Preferably, the adhesive is non-porous and has a low diffusion coefficient.

[0045] Support piston assembly 62 is designed to counteract the force applied by sealer head drive piston assembly 116 and maintain a seal between lower surface 68 and beverage can assembly 72.

[0046] Referring now to FIG. 4, sealer assembly 94 includes sealer head 98, and sealer shaft 96. Sealer head 98 is typically manufactured using a heat conductive material, for example, copper. Sealer head 98 includes large bore 110 and small bore 112. Large bore 110 is configured to house heating element 111. Heating element 111 may be configured to operate continuously in a heating mode or arranged to cycle on and off. Heating element 111 may be a lightweight impulse type heater or any other convenient type of heater. Small bore 112 is configured to house temperature sensor 113. Passage 102 is machined into sealer shaft 96 for routing leads to heating element 111 and temperature sensor 113.

[0047] Turning again to FIGS. 2A and 2B, sealer shaft coupling end 100 is adapted to receive upper alignment coupling 114, which is connected to sealer head drive piston assembly 116. Other techniques for connecting sealer shaft coupling end 100 may be used. Sealer head drive piston assembly 116 is mounted to horizontal top end frame 56 and comprises cylinder 117, piston 119 and shaft 118. Sealer head drive piston assembly 116 is designed to impart a sealing force through heated sealer head 98 onto sealant material 139 on the area surrounding opening 75 in bottom 73.

[0048] The area surrounding opening 75 may be, for example, tin-plated steel, aluminum, or lacquered aluminum.

[0049] Shaft 118 and piston 119 can move in an axial direction, which in the embodiment illustrated is up and down. Shaft 118 and piston 119 are illustrated in their lowered position. Shaft 118 and piston 119 can be driven by any convenient means, for example, by pneumatic actuation. Forcing compressed air into the space beneath piston 119 inside cylinder 117 causes shaft 118 and piston 119 to move in an upward direction. Conversely, releasing air from the space underneath piston 119 inside allows shaft 118 and piston 119 to move downwardly. When shaft 118 and piston 119 are in a raised position, sealer assembly 94 is not touching beverage can assembly 72. The positions of shaft 118 and piston 119 may be adjusted either manually, by using sealer head drive piston position controller 120, or automatically.

[0050] FIG. 5 provides a flowchart identifying particular steps of a preferred method for preparing an evaporator 24. Specifically, the flowchart describes a technique for vacuum sealing an evaporator 24 attached to the inside of a beverage can 72. The techniques described may be utilized to vacuum seal evaporator 24 attached to other types of containers or an evaporator 24 not attached to any container.

[0051] In step 200, evaporator 24, containing a refrigerant, for example, water gel is mounted in vacuum sealing apparatus 50. Support piston assembly 62 supports evaporator 24 and beverage can 72. Since a vacuum will have to be maintained in vacuum chamber 80, the force applied by support piston assembly 62 must be sufficient to maintain an airtight seal between evaporator 24 and vacuum chamber 80. The force applied by support piston assembly 62 is typically set slightly higher than the force applied by sealer head drive piston assembly 116. The maximum pressure applied by sealer head drive piston assembly 116 ranges from approximately 150 psi to approximately 600 psi, and the pressure applied by support piston assembly 62 is greater than the pressure applied by the sealer head drive piston assembly for at least the time that sealer head drive piston assembly 116 is applying that pressure.

[0052] After evaporator 24 and beverage can 72 are in place, vacuum chamber 80 is evacuated in step 202. During evacuation, the pressure inside vacuum chamber 80 will depend on the vapor pressure of the particular refrigerant to be used, but typically ranges from atmospheric pressure to between approximately 1 torr and approximately 60 torr. When water gel is used as the refrigerant, evaporator 24 is typically evacuated until the water evaporating from the water gel clears the air from evaporator 24. The evacuation may be accomplished at pressures slightly below or equal to the vapor pressure of the refrigerant at the temperature that the evacuation is carried out. The evacuation serves to sweep contaminants, such as air, wash solvents, and non-condensable gases from evaporator 24. The presence of non-condensable gases should be minimized everywhere in the system. Non-condensable gases can form a barrier through which refrigerant vapor must diffuse before it can condense. If such gases are present to an appreciable degree, the refrigeration device might operate at a rate that is undesirably limited.

[0053] When appropriate gauge readings are obtained, for example, approximately 10 torr for approximately 10 seconds, sealant material 139 is positioned over at least opening 75 in bottom 73 in step 204. This may be accomplished in any of several different ways. Evaporator 24 may have been initially mounted inside vacuum sealing apparatus 50 with a piece of sealant material 139 in place and tacked at one edge, but curled to allow passage of the vapor out of evaporator 24. Alternatively, evaporator 24, when mounted inside vacuum sealing apparatus 50, may have had a disk of sealant material 139 tack welded at a single point to the evaporator opening and oriented in a partially vertical plane. Sealing head 98 may be used to manipulate sealant material 139 into place. In another variation, a sealant-feeding device may be used to position sealant material 139.

[0054] Once sealant material 139 is in place, sealer head 98 is positioned in step 206. Movement of sealer head drive piston assembly 116 may position sealer head 98.

[0055] Sealing head 98 welds sealant material 139 into place in step 208 by applying heat and pressure to at least the portion of sealant material 139 that covers the area surrounding opening 75. Sealing head 98 typically heats up to a temperature ranging from approximately 300° F. to approximately 800° F. and can thus heat sealant material 139 to a temperature ranging between approximately 300° F. and 800° F. The pressure applied ranges from approximately 150 psi to approximately 600 psi.

[0056] Once sealant material 139 is welded into place, sealing head 98 is withdrawn in step 210. Sealer head drive piston assembly 116 moves to a raised position, and sealing head 98 is lifted off of the portion of sealant material 139 that covers the area surrounding opening 75.

[0057] After sealant material 139 is allowed to cool, vacuum chamber 80 is pressurized in step 212 to approximately atmospheric pressure. Providing appropriate heat conduction paths away from the area of sealant material 139 may minimize the time required for cooling sealant material 139. Finally, evaporator 24 is removed from vacuum sealing apparatus 50 in step 214.

[0058] FIGS. 6-8, illustrate a vacuum filling and sealing apparatus 250, and variations thereof, according to particular embodiments of the invention. Apparatus 250 is a actually variation of the vacuum sealing device 50 discussed above, further including additional elements which enable the introduction of desiccant (or other material) into a container, for example, an absorber while it is being evacuated, but before it is sealed. The vacuum filling and sealing apparatus 250 may be used to prepare absorbers 32 for use in a refrigeration device, such as refrigeration device 20 represented in FIG. 1. It should be noted that the vacuum filling and sealing apparatus 250 is also capable of preparing an evaporator 24 for use in a refrigeration device, such as refrigeration device 20.

[0059] Many elements and components in vacuum filling and sealing apparatus 250 are identical to elements and components described above with reference to vacuum sealing apparatus 50 of FIG. 2 and are so indicated by use of the same reference numbers. Descriptions of these elements and components will not be repeated.

[0060] FIG. 6 illustrates absorber 32 mounted in vacuum filling and sealing apparatus 250. Absorber 32 includes neck 126 and collar 132. Absorber neck 126 includes an opening at its top. Absorber 32 as depicted is mounted in apparatus 250 upright with respect to normal use position. However, any convenient orientation can be used.

[0061] Support shaft 65 and support piston 63 of support piston assembly 62 are shown in a lowered position. Lower vacuum chamber flange 124 is designed to mate with absorber neck 126 and collar 132. Support yoke 128 is provided to mate with absorber neck 126 and collar 132 and to provide a means to support absorber 32. Absorber neck 126 passes through an opening in the top of support yoke 128. Absorber 32 is supported by collar 132, which rests on top of support yoke 128. An o-ring may be mounted in the lower bore of the lower flange to facilitate sealing the joint where absorber neck 126 mates with vacuum chamber 80. Alternatively, an o-ring can be slipped around absorber neck 126 and rest on top of collar 132.

[0062] When compressed air is forced into the space beneath support piston 63 inside support piston cylinder 61, absorber 32 is pushed upwards so that absorber neck 126, collar 132 and o-ring mate with lower vacuum chamber flange 124. In order to avoid applying a large load (as required for maintaining a seal on the vacuum chamber 80) directly onto the o-ring and possibly over-compressing it, collar 132 typically seats on lower vacuum chamber flange 124 allowing space for a standard o-ring to be placed around absorber neck 126 and between collar 132 and lower vacuum chamber flange 124. See FIG. 8 for a detailed view.

[0063] Referring again to FIG. 6, vacuum filling and sealing apparatus 250 includes desiccant feed tube 136 that originates at desiccant hopper 290, which may be located on top of apparatus 250. Desiccant hopper 290 may be heated and may also include provisions for degassing and preparing the desiccant. Desiccant feed tube 136 passes downwardly through horizontal top end frame 56, horizontal center frame 58, upper flange 82 and into vacuum chamber 80. Desiccant feed tube 136 may be routed other ways, but at least a portion of it should be located inside vacuum chamber 80. Desiccant feed tube 136 is movable vertically and is also rotatable around a vertical axis that passes through the center point of port 134. Depending on the specific arrangement, desiccant feed tube 136 may realize freedom of movement in other directions as well. It must be movable such that an opening at the bottom of desiccant feed tube 136 can be positioned just inside or near the opening in absorber neck 126. Desiccant feed tube 136 may include a desiccant flow control device 292. Control device 292 may be, for example, a valve. Desiccant feed tube 136 may also include a flow metering or volume-measuring device 294.

[0064] Referring now to FIG. 7, absorber neck 126 is shown mated to and partially passing through lower flange 124. Foil seal 138 is secured to the top of absorber neck 126 and oriented in a substantially vertical direction, as shown. Foil seal 138 is desirably metallic foil with a heat-activated adhesive on one side that can secure foil seal 138 to the area surrounding the open of absorber neck 126. Foil seal 138 may be, for example, aluminum, aluminized Mylar, or copper. Preferably, the adhesive is non-porous and has a low diffusion coefficient. Tack welding or any other convenient method may also be used to secure foil seal 138 to the top of absorber neck 126. The particular embodiment shown does not include a sealant-feeding device. Using such an arrangement, foil seal 138 can be attached to absorber neck 126 prior to inserting absorber 32 into vacuum filling and sealing apparatus 250 and either desiccant feed tube 136 or sealer head 98 can be used to maneuver foil seal 138 to a substantially horizontal orientation so that it can be welded to the top of absorber neck 126 by sealer head 98.

[0065] Dashed lines illustrate desiccant feed tube 136 positioned so that the open end of tube 136 is seated and sealed in recessed area 133 machined into lower vacuum chamber flange 124. Desiccant feed tube 136 can be moved to this position to isolate the desiccant feed system from atmospheric contamination when vacuum chamber 80 is pressurized. Tube 136 is typically only removed from recessed area 133 after vacuum chamber 80 has been evacuated to a pressure between approximately 1 millitorr and 1000 millitorr. Side seal 135 and bottom seal 137 maintain an airtight seal, as shown.

[0066] FIG. 8 illustrates a partial view of an alternate embodiment of a vacuum filling and sealing apparatus 250. In this embodiment heating element 99, which is only required to seal a circular pattern of sealant material 139, is hollow. Sealer assembly 94 is also hollow. Desiccant feed tube 136 is situated inside sealer assembly 94 and heating element 99 and is movable axially up and down independently from the motion of sealer assembly 94.

[0067] Punch die 140 is installed outside sealer assembly 94. Punch die 140 is arranged so that it when it is lowered, it cuts sealant material 139 to a size that covers at least the opening in the top of absorber neck 126. Punch die 140 is connected to sealer assembly 94 through spring 142, but may be connected by any other convenient means. Alternately, punch die 140 may be configured to move independently from the motion of sealer assembly 94.

[0068] Sealant material 139 may be automatically advanced over the opening on absorber neck 126. This can be accomplished by any convenient automatic sealant feeding means, for example, by cams or levers, which are driven by the motion of desiccant feed tube 136 or by the motion of sealer assembly 94. Alternatively, automatic sealant feeding could be accomplished through independent synchronization with the movement of desiccant feed tube 136 or sealer assembly 94.

[0069] FIG. 9 provides a flowchart identifying steps used to prepare an absorber 32 according to the invention. Specifically, FIG. 9 describes steps for evacuating an absorber, filling it with desiccant, and vacuum sealing it. The absorber 32 is first mounted in vacuum filling and sealing apparatus 250 in step 300. Vacuum chamber 80 must be sealed at the mating joint between absorber neck 126, collar 132 and lower vacuum chamber flange 124. This sealing may be accomplished, for example, by inserting an o-ring around absorber neck 126 and above collar 132.

[0070] Vacuum chamber 80 is then evacuated in step 302. Evacuation pressures used during processes involving absorbers 32 typically range from approximately 1 to 1000 millitorr. Absorber 32 is desirably made as free of condensable gases as possible during the evacuation process.

[0071] If provisions for adding desiccant are not included in the vacuum sealing apparatus, then absorber 32 is filled with desiccant, prior to being inserted into the vacuum sealing apparatus. Otherwise, desiccant feed tube 136 is positioned either near or inside absorber neck 126 in step 304 and desiccant, for example, molecular sieve is added in step 306 to absorber 32. A desiccant feed control system may control the flow of desiccant through desiccant feed tube 136 and into absorber 32. Materials that may be suitable desiccants are those that have aggressive refrigerant vapor-binding properties, low chemical reaction heats, and are not explosive, flammable or toxic. These materials are available in a variety of forms, including flakes, powders, granules, as well as supported on inert shapes or bound within clays. It is desirable that the material has sufficient vapor flow passages through it so that refrigeration performance is not limited by the passage of refrigerant vapor through the desiccant. Additionally, the desiccant should be able to transfer heat to the heat sink material, and thus be in good thermal contact with the inner surface of absorber 32.

[0072] After the amount of desiccant required for the cooling operation has been added to absorber 32, desiccant feed tube 136 is withdrawn in step 308.

[0073] Sealant material 139 is then positioned over the opening in absorber neck 126 in step 310. This may be accomplished in any convenient way, for example, by automatically feeding sealant material 139 to an area between sealing head 98 and absorber neck 126. An appropriately sized piece of sealant material 139 may then be cut to fit over the opening in absorber neck 126.

[0074] After sealant material 139 is in place, sealer assembly 94 is positioned in step 312 to weld sealant material 139 so that it covers the opening in the top of absorber 32. Sealer head 98 applies heat and pressure to sealant material 139 in step 314. These pressures and temperatures may be identical to those described above regarding sealing evaporator 24.

[0075] After sealant material 139 is secured to absorber 32, sealer 94 is withdrawn in step 316 and sealant material 139 is allowed to cool. When sealant material 139 is sufficiently cooled, vacuum chamber 80 is pressurized in step 318 to approximately atmospheric pressure. Absorber 32 is then removed from the vacuum filling and sealing apparatus in step 320.

[0076] After vacuum sealing evaporator 24 and vacuum filling and sealing absorber 32, the two components may be mated together by bonding sealant material 139 on each component together. Sealant material 139 provides a means to prevent the inadvertent flow of refrigerant vapor between evaporator 24 and absorber 32. Sealant material 139 may also form a seal around the joint during actuation, when the joint between evaporator 24 and absorber 32 might otherwise provide a leakage path from the outside.

[0077] As illustrated in FIG. 10, the techniques described herein may be suitable for automation. FIG. 10 illustrates vacuum filling and sealing apparatus 250 incorporating a system for controlling the techniques described herein. Controller 252, for example, a computer including processor 254 and memory storage unit 256, is connected to receive various input signals from various sensors located throughout apparatus 250. Processor 254 is configured for processing various input signals, and for timing of all events. Memory storage unit 256 is configured to store various information related to the operation of vacuum filling and sealing apparatus 250. Controller 252 is connected to transmit signals to various control devices, which interface with vacuum filling and sealing apparatus 250.

[0078] Controller 252 can be adapted to fully automate the operations described herein including automatically securing an open end of a container to a port on the vacuum chamber, applying a low pressure to the vacuum chamber, positioning sealant material to cover at least the open end of the container and a portion of a surface surrounding the open end, and attaching the sealant material to the surface surrounding the open end of the container so that it covers the over the open end of the first container. Controller 252 can also be adapted to introduce a substance, for example, a desiccant into the container before positioning the sealant material. Controller 252 can also be adapted to automatically insert and remove containers into and out of vacuum filling and sealing apparatus 250.

[0079] It should be understood that similar principles described with reference to FIG. 10 could be applied to provide control to a vacuum sealing apparatus 50 and that such a control system would actually be simpler, because of the fewer sensing points needed and the fewer control points needed.

[0080] The inputs to controller 252 include signals received from sealer head drive piston assembly position sensor 258, desiccant flow metering device 260, sealer head temperature sensor 262, vacuum chamber pressure sensor 264, and support piston position sensor 266. The outputs transmitted by controller 252 include signals sent to sealer head temperature controller 270, vacuum chamber suction device 272, sealant material feeder driver device 274, desiccant feed tube positioning device 276, desiccant flow control device 278, sealer head drive piston assembly position controller 120, support piston position controller 122, and container replacement mechanism controller 280.

[0081] Container replacement mechanism 280 may include any device or combination of devices adapted to automatically remove a vacuum filled and sealed container from vacuum filling and sealing apparatus 250 and to place a new container in apparatus 250. Such an action may be accomplished, for example, by using a robotic arm configured to move containers to and from automatically operated conveyer belts. Output signals transmitted by controller 252 are responsive to input signals received from the sensors.

[0082] Controller 252 is also connected to a workstation computer 282. An operator may access various data, including control system parameters at workstation computer 282. The operator may input additional parameters, delete existing parameters, or modify existing parameters. The operator may also use workstation computer 282 to access historical system operational data stored in memory storage unit 256 by processor 254.

[0083] It is to be understood that while the invention has been described in conjunction with the detailed description thereof, the foregoing description is intended to illustrate and not limit the scope of the invention, which is defined by the scope of the appended claims. Other aspects, advantages, and modifications are within the scope of the following claims.

Claims

1. An apparatus for vacuum sealing a container, the apparatus comprising: a vacuum chamber in communication with a vacuum source, the vacuum chamber having at least a first port and an internal pressure; a securing device adapted to secure an open end of the container to the first port of the vacuum chamber; and a heating member at least a portion of which is located inside the vacuum chamber, the heating member is adapted to apply heat to a heat-activated sealant material positioned to cover at least the open end of the container.

2. The apparatus of claim 1 wherein the securing device comprises a piston assembly adapted to impart a force against the container.

3. The apparatus of claim 2 wherein the piston assembly enables mating of the open end of the container to the first port on the vacuum chamber.

4. The apparatus of claim 1 further comprising a sealant material feeding device adapted to position the sealant material to cover at least the open end of the container.

5. The apparatus of claim 4 wherein the sealant material feeding device is further adapted to operate automatically.

6. The apparatus of claim 1 further comprising a sealant material cutting member at least a portion of which is located inside the vacuum chamber, the sealant material cutting member is adapted to cut the sealant material to a size that covers at least the open end of the container.

7. The apparatus of claim 6 wherein the sealant material cutting member is mounted to the heating member by a spring-loaded connection.

8. The apparatus of claim 6 wherein the sealant material cutting member is further adapted to operate automatically.

9. The apparatus of claim 1 wherein the heating member comprises a surface adapted to mate with a portion of the sealant material, the portion of sealant material is positioned proximate a surface of the container at least partially surrounding the open end of the container.

10. The apparatus of claim 1 wherein the heating member is further adapted to heat the sealant material to a temperature that is between approximately 300° F. and approximately 800° F.

11. The apparatus of claim 1, wherein the heating member is further adapted to apply pressure to the sealant material, and the pressure is between approximately 150 pounds per square inch and approximately 600 pounds per square inch.

12. The apparatus of claim 1 wherein the vacuum source is adapted to create an internal pressure in the vacuum chamber that is between approximately 1 torr and approximately 60 torr.

13. The apparatus of claim 1 further comprising: a controller with at least one input terminal and at least one output terminal; at least one sensor connected to the at least one input terminal, at least one of the sensors adapted to sense the internal pressure of the vacuum chamber; at least one actuating device connected to the at least one output terminal, at least one of the actuating devices adapted to actuate the vacuum source; wherein the controller is adapted to receive an input signal from the at least one sensor through the at least one input terminal, process the input signal, and transmit an output signal responsive to the input signal through the at least one output terminal to the at least one actuating device.

14. The apparatus of claim 13 wherein the controller is further adapted to cause at least one of the actuating devices to perform at least one action selected from a group consisting of: securing the open end of the container to the port on the vacuum chamber, actuating the vacuum source to create an internal pressure in the vacuum chamber, positioning the sealant material to cover at least the open end of the container, and applying heat and pressure to the sealant material proximate a surface at least partially surrounding the open end of the container.

15. An apparatus for vacuum sealing and filling a container, the apparatus comprising: a vacuum chamber in communication with a vacuum source, the vacuum chamber having at least a first port and an internal pressure; a securing device adapted to secure an open end of the container to the first port of the vacuum chamber; a heating member at least a portion of which is located inside the vacuum chamber, the heating member is adapted to apply heat to a heat-activated sealant material positioned to cover at least the open end of the container; and a hollow feed tube at least a portion of which is located inside the vacuum chamber.

16. The apparatus of claim 15 wherein the heating member comprises an internal passage, the hollow feed tube has an open end that can be in communication with the vacuum source and at least a portion of the hollow feed tube passes through the internal passage of the heating member.

17. The apparatus of claim 15 wherein the hollow feed tube is adapted to load a material into the container through the open end of the container.

18. The apparatus of claim 15 wherein the hollow feed tube comprises an open end and the hollow feed tube can be positioned so that the open end of the hollow feed tube is isolated from the vacuum source.

19. The apparatus of claim 18 wherein the open end of the hollow feed tube can be isolated from the vacuum source by mating the open end of the hollow feed tube with a recessed sealing area inside the vacuum chamber.

20. The apparatus of claim 15 wherein the vacuum source is adapted to create a pressure inside the vacuum chamber that is between approximately 1 millitorr and approximately 1000 millitorr.

21. The apparatus of claim 15 wherein the securing device comprises a piston assembly adapted to impart a force against the container.

22. The apparatus of claim 21 wherein the piston assembly enables mating of the open end of the container to the first port on the vacuum chamber.

23. The apparatus of claim 15 further comprising a sealant material feeding device adapted to position the sealant material to cover at least the open end of the container.

24. The apparatus of claim 23 wherein the sealant material feeding device is further adapted to operate automatically.

25. The apparatus of claim 15 further comprising a sealant material cutting member at least a portion of which is located inside the vacuum chamber and the sealant material cutting member is adapted to cut the sealant material to a size that covers at least the open end of the container.

26. The apparatus of claim 25 wherein the sealant material cutting member is mounted to the heating member by a spring-loaded connection.

27. The apparatus of claim 25 wherein the sealant material cutting member is adapted to operate automatically.

28. The apparatus of claim 15 wherein the heating member comprises a surface adapted to mate with a portion of the sealant material positioned proximate a surface of the container, the surface at least partially surrounding the open end of the container.

29. The apparatus of claim 15 wherein the heating member is further adapted to heat the sealant material to a temperature that is between approximately 300° F. and approximately 800° F.

30. The apparatus of claim 15 wherein the heating member is further adapted to apply pressure to the sealant material, and the pressure is between approximately 150 pounds per square inch and approximately 600 pounds per square inch.

31. The apparatus of claim 15 wherein the vacuum source is adapted to create a pressure inside the vacuum chamber that is between approximately 1 torr and approximately 60 torr.

32. The apparatus of claim 15 further comprising: a controller with at least one input terminal and at least one output terminal; at least one sensor connected to the at least one input terminal, at least one of the sensors adapted to sense the internal pressure of the vacuum chamber; at least one actuating device connected to the at least one output terminal, at least one of the actuating devices adapted to actuate the vacuum source; wherein the controller is adapted to receive an input signal from the at least one sensor through the at least one input terminal, process the input signal, and transmit an output signal responsive to the input signal through the at least one output terminal to the at least one actuating device.

33. The apparatus of claim 32 wherein the controller is further adapted to cause at least one of the actuating devices to perform at least one action selected from a group consisting of: securing the open end of the container to the port on the vacuum chamber, actuating the vacuum source to create an internal pressure in the vacuum chamber, feeding a material into the container through the open end of the container, positioning the sealant material to cover at least the open end of the container, and applying heat and pressure to the sealant material proximate a surface at least partially surrounding the open end of the container.

34. A method of preparing a container comprising: securing an open end of the container to a port on a vacuum chamber, the open end having a surface at least partially surrounding the open end; actuating a vacuum source in communication with the vacuum chamber to at least partially evacuate the vacuum chamber; positioning a sealant material to cover at least the open end of the container and a portion of the surface at least partially surrounding the open end of the container; and attaching the sealant material to the surface at least partially surrounding the open end of the container to cover at least the open end of the container.

35. The method of claim 34 wherein securing the open end of the container to the port on the vacuum chamber comprises applying a seating force with a movable assembly.

36. The method of claim 34 wherein actuating the vacuum source to at least partially evacuate the vacuum chamber results in a pressure inside the vacuum chamber that is between approximately 1 torr and approximately 60 torr.

37. The method of claim 34 wherein actuating the vacuum source to at least partially evacuate the vacuum chamber results in a pressure inside the vacuum chamber that is between approximately 1 millitorr and approximately 1000 millitorr.

38. The method of claim 34 wherein positioning the sealant material comprises using an automatic sealant feeding mechanism.

39. The method of claim 34 wherein attaching the sealant material comprises applying heat and pressure to at least a portion of the sealant material proximate the surface at least partially surrounding the open end of the container.

40. The method of claim 34 further comprising introducing a material into the container through the open end of the container before positioning the sealant material.

41. The method of claim 40 wherein the material comprises a desiccant.

42. The method of claim 34 further adapted to be automatically repeated.

43. A container prepared according to the method of claim 34.

44. A container prepared according to the method of claim 40.