MXPA99007438A - Process and apparatus for cryogenically cleaning residue from containers and intermediate bulk containers designed for cryogenic cleaning - Google Patents

Abstract

A method and apparatus for the cleaning of residue from the surface of a container where the method comprises cooling the container and residue adhered to the container surface to a low temperature, substantially embrittling the residue, fragmenting the residue, separating the residue from the surface of the container and removing the residue from the container. The container is placed in an enclosure with an opening in the top of the enclosure to permit access to the interior of the container when a container lid is removed. The system includes a rotating base to turn the container to facilitate freezing and removal of the residue. Further, there is a commodity container adapted for cryogenic cleaning having a cylindrical body open substantially the full diameter at the top with an outwardly extending flange and an inner sealing band extending to a height above the top of the flange, wherein the flange and the band form an acute angle. On the body sits a lid having a cylindrical side wall descending down and terminating with an outwardly extending flange forming an obtuse angle with the side wall, wherein the lid sits on the open end of the body with the lid flange above the body flange and the sealing band overlapping the lid side wall. The container has a sealing gasket in the channel formed by the inner sealing band, the body flange and the lid flange with a retaining ring applying a force against the body flange and the lid flange for sealing against the gasket.

Description

SYSTEM TO REMOVE CRYOGENICALLY WASTE FROM CONTAINERS CROSS REFERENCES OF RELATED REQUESTS This Application is a continuation in part of Application number 08 / 422,547, filed April 12, 1995, which is a continuation in part of Application number 08 / 206,731, filed March 7, 1994, now issued as US Patent. 5,456,085.

BACKGROUND OF THE INVENTION The present invention relates generally to the removal of waste materials from containers for disposal or recycling. More specifically, the present invention relates to a method and apparatus for cleaning waste from the surface of containers by using low temperatures. In addition, the present invention relates to a container with characteristics that facilitate cleaning by using low temperatures. Disposal of waste has become a major concern due to the environmental problems associated with hazardous materials. Of even more immediate concern are the economic problems associated with the increasing costs and reduced capacity of sanitary landfills, as well as stricter government regulations that relate to waste generators, environmental pollution, employee safety and fire prevention. Therefore, the elimination of containers and the residual materials that remain in them can be a costly and time-consuming task. Emphasis has been placed on cleaning waste from containers so that only waste, and not containers, are subject to costly disposal of hazardous waste. This leaves the containers available to be reused, recycled, or disposed of in a landfill of less expensive non-hazardous material waste. One benefit of using an intermediate volume container (IBC) is the ability to reuse the containers. IBCs range in size from 321.7 liters to 2,082 liters and come in a variety of forms and are manufactured using a variety of materials such as plastic, aluminum, steel and stainless steel. To properly reuse an IBC the container must be cleaned first. Frequently the product that is being transported in the IBC is viscous, pegasy and / or dangerous. Sometimes the residue sets after exposure to moisture or water, or expands its volume as a result of the cleaning agent. In addition, the cleaning of these containers has become more difficult as a result of the new and ever changing laws of EPA, OSHA, the local Fire Department and the laws of the area.

The government of E.U.A. has established guidelines under the Resource Conservation and Recovery Act (RCRA) that specify cleaning requirements for the disposal of containers as non-hazardous waste. However, some states are imposing bans on the disposal of even clean containers in landfills as a solution to the problem of rapidly diminishing the capacity of landfills. This leaves the reuse or recycling of the containers as the only alternative. A wide range of waste products are subject to the costly disposal of hazardous waste. Some of these residues include, but are not limited to, tars, lubricants, mastics, inks, coatings, solvents, adhesives, sealants, paints, etc. There is a range of traditional cleaning methods to remove such waste from product containers. These methods include the application of water, steam, soaps, detergents, chemical solvents, abrasives and brushing equipment. All these methods result in the creation of an increased volume of waste that may be more difficult to remove than the original waste. These methods can be expensive due to the need for expensive materials, equipment and hard work. Even if the waste is not considered hazardous, there may be restrictions imposed by municipal sewage treatment districts that require expensive pretreatment before the waste and washing liquid are discharged into the sewer system.

Typically, solvents, caustic materials and various soaps or detergents have been used to clean various containers including IBCs. The type of cleaning agent used depends on the type of waste that is to be removed from the container. No matter what cleaning agent is used, the amount of the waste stream is always increased and the removed residue is mixed with the cleaning agent. This method results in, but is not limited to, an increase in disposal costs, a waste that can not be easily and economically recycled, potential risks to employee health, volatile organic compound (VOC) emissions to atmosphere, and potential environmental obligations. In addition, some cleaning techniques such as blasts of sand, bursts of spherical particles and burst with sodium carbonate cause damage to the metal by making holes and thinning the walls of the IBC. As an example of traditional cleaning methods, cleaning with chemical solvent involves numerous disadvantages. Solvents are expensive. These require special care and handling due to their combustion capacity, their corrosive nature and / or volatility. Special ventilation equipment may be required to recover volatile organic compounds that evaporate when used. Additional equipment may be necessary to separate the solvent from the wash solution from the waste residue to recycle the solvent. If it is not separated, the volume of the waste product increases enormously. Employees require additional training to safely handle equipment and materials. Special inspections, building codes and local requirements can be difficult to meet, or require special facilities for cleaning equipment to be built. In the end, most small organizations do not have the resources to properly handle the problems associated with the disposal or recycling of containers loaded with waste when using traditional methods. There is a measurable space between the traditional cleaning methods in existence to remove waste from containers and the industry's requirements to clean containers with a cost-effective and environmentally safe procedure. Therefore, there is a need for a method and apparatus for cleaning container waste that does not have the deficiencies, risks and environmental obligations associated with traditional cleaning methods. In particular, large product containers are heavy and difficult to handle due to their size. Many of them have very small openings which makes it difficult to remove the residue. Therefore there is a need for new containers that facilitate the removal of waste using cleaning methods with low temperatures. Similarly, there is a need for new appliances to complement these new containers and allow the use of new cleaning methods at low temperatures.

BRIEF DESCRIPTION OF THE INVENTION Accordingly, the present invention is directed to providing an environmentally safe, cost-effective and simple method and apparatus for cleaning product residues expended from the internal surfaces of product containers. In one aspect of the invention, the method involves cooling the container charged with residue to a temperature where the residue becomes brittle, fragmenting the residue, separating the residue from the surface of the container and removing the residue. Preferably, the container is cooled by placing it in an isolated chamber and putting it in contact with a cold cryogen. More preferably, the lid of the container is removed and the residue is removed while the container is in the insulated chamber provided by the container extending through an opening in the upper part of the insulated chamber. Another aspect of the invention provides an insulated chamber with an opening in the upper part large enough to allow a container to extend from one side to the other of the same by applying gaskets to seal the opening against the container, a base for supporting the container, a plurality of cryogen sprinklers located on a wall of the chamber and at the base. Preferably, the base rotates so that the cryogen sprinklers can be located on a portion of the wall but obtain sufficient coverage of the container as it rotates past the sprinklers.

Even in another aspect of the invention, a container is provided that facilitates the cleaning thereof by the method and apparatus of the invention. The container has a cylindrical body, a separable lid, a sealing gasket between the body and the lid and a retaining ring that holds the lid to the body. In detail, the body has an opening at the upper end of substantially the same width of the container, the upper end having an outwardly extending flange and an internal sealing ring extending upwardly above the height of the rim. The lid has a side wall that extends downward and ends with an outwardly extending flange which is positioned proximate the body rim when the lid is placed on the body, and the side wall is close to the inner sealing ring of the body. body. The container also includes a sealing gasket disposed in the channel defined by the internal sealing jacket, the body flange and the flange of the lid, and includes a retaining ring that surrounds the body flange and the flange of the cover for apply a force against the body flange and the flange of the cap to seal them against the packing. The preferred embodiments of the invention avoid the use of solvents and other washing liquids so that the hazardous material to be removed is limited to the original waste itself. These modalities also require less equipment and less work to operate than traditional cleaning methods and reduce health risks for operations personnel. The preferred embodiments substantially remove the waste from the container to meet the disposal requirements of the U.S. government. and the industrial requirements for the reuse of the container. Additional advantages of the present invention will become apparent from the accompanying drawings and the detailed description of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a front plan view of one embodiment of the container of the present invention. Figure 2 is a side plan view of the container of Figure 1 showing the detail of the lower outlet tube. Figure 3 is a top plan view of the container of Figure 1 showing the detail of the lower outlet tube. Fig. 4 is a cross-sectional side view of the container of Fig. 1. Fig. 5 is an enlarged exploded cross-sectional view of Fig. 4 showing the detail of the body flanges and the lid and retaining ring. Figure 6 is an enlarged side cross-sectional view showing the detail of the body flanges and the cap and retaining ring of Figure 5 in a closed position.

Figure 7 is an enlarged top plan view of a clamp clip in the retaining ring when installed in a container. Figure 8 is a side plan view of the clamp clip of Figure 7 when installed on a container. Figure 9 is a cross-sectional view of the clamp clip of Figure 8 taken along line 9-9. Figure 10 is an enlarged cross-sectional view of the support sleeve of the container and the base. Figure 11 is an enlarged perspective bottom view taken from a corner of the base showing the entrance way of the forklift cavity. Figure 12 is a cross-sectional side view of a dual-chamber cryogenic container treatment system showing an open container and the lid in the dual chambers. Fig. 13 is a top cross-sectional view taken along line 13-13 of Fig. 12 showing the details of the dual cryogenic container treatment chamber system without a container and lid in the chambers. Figure 14 is a side plan view of a rotating camera base that is used in the system of Figure 12 to support a container.

Figure 15 is a bottom plan view of the base of the chamber of Figure 14.

DETAILED DESCRIPTION OF THE DRAWINGS AND THE MODALITIES CURRENTLY PREFERRED In Figures 1 to 11 a preferred embodiment of the intermediate volume container adapted to facilitate the cryogenic cleaning of waste therein is shown. As shown in Figures 1 and 2, the intermediate volume container 20 includes a cylindrical body 22 with a round plate bottom 24 and a support sleeve 26 attached to the base 28. The container further includes a lid 30 with a guard ring 32 on the top. Holding the lid 30 to the body 22 is a retaining ring 34 that is held together with a clamp clip 36. At the bottom of the container, an outlet tube 38 and a discharge valve 40 for the containers that are designed can be included. for carrying highly viscous liquids or materials. Preferably, the container has two main parts: the lid and the body / bottom / base unit which are held together with the retaining ring 34. The container can also be constructed with other separable configurations such as those where there are three separable units: a lid, a body and a base / lower plate that are held together by two sets of retaining rings. Regardless of the configuration chosen, it is preferred that the container be constructed from carbon steel, aluminum or stainless steel. The interior surfaces of the container should preferably be of a highly polished surface, preferably using an electropolishing method. As can be seen in Figure 3, the base has separate corners 42 to allow 4-way access for the forklift. This preferred construction can be seen in greater detail in Figure 11.

Referring again to Figure 3, an inspection hole and a cover 44 can be provided in the lid 30 for easy access to the interior of the container for loading the product materials, or for inspection of the interior of the container. As shown in detail in cross section in Figure 4, the container has numerous features not found in other IBCs. The container is opened by a lid 30 that spans the full width of the body 22 of the container. At the joint between the lid 30 and the body 22, an internal seal band 46 is provided which extends above the body 22 of the container and not only helps prevent material from slipping out of the container, but also during cleaning with the cover removed, the sealing band 46 also protects the flange 48 of the body (Figure 5) from the destructive forces coming from the cleaning equipment.

The cover 30 is preferably in the form of a rounded plate to obtain a structural force and a complete drainage of the contents. The exact round shape can vary and include, but is not limited to, a standard elliptical head. However, a flat top with the corresponding decrease in structural strength can also be used. Similarly, the bottom 24 of the container is preferably in the form of a rounded plate for structural strength. The exact shape may vary and include, but is not limited to, an elliptic head or even a hemispherical head. A rounded plate shape provides a low point at the center where an outlet tube 38 can be connected. Referring to Figure 4, at the bottom of the cylindrical container there is an outer cylindrical sleeve 26 and an internal cylindrical sleeve 50 for support. The outer jacket 26 depends on the lower end 52 of the cylindrical body 22 of the container and is connected to the base 28, which is shown in greater detail in Figure 10. The internal support jacket 50 depends on the underlying side of the bottom disc 24 and is connected to the base 28 in the inner part of the cavities 54 for forklifts. The part The interior of the inner support sleeve 50 is completely open through the bottom of the base 28 to allow the cryogen to be sprayed directly into the bottom of the container. The internal support sleeve 50 is concentric with the outer support sleeve 26 forming an annular space 56 between the two sleeves. A plurality of festooned openings 58 are provided in the separate inner support jacket around the circumference of the located shirt where the sleeve 50 is attached to the plate 24 lower. An opening 60 is also provided in the inner sleeve 50 to allow the outlet tube 38 to pass from the central point of the container to the annular space 56 where a discharge valve 40 is threaded to the end of the outlet tube. An opening 62 is provided in the outer jacket to allow access to the discharge valve 40. The inner sleeve 50 being cylindrical and open at the base, the containers can be stacked securely. For this purpose, the guard ring 32 of the lid will need to be slightly smaller in diameter than the inner support sleeve 50. With these relative dimensions, the ring 32 of the lid of the lower container could fit inside the inner sleeve 50 of a container stacked on top of it. Many of the IBCs in the market have covers that are simply covered with inspection holes in the upper part of the container and restrict full access to the interior of the container. However, there are round IBCs on the market that have covers / covers that can be removed to expose the full diameter of the interior of the IBC tank. These IBCs were designed and manufactured before the new UN / DOT standards that went into effect on October 1, 1996. With the new standards, the IBC designs with round top that existed with the completely removable lid no longer met the requirements. new UN / DOT standards that required IBCs to pass hydrostatic tests at pressures of 2.07 kg / cm2 for 10 minutes. Typical IBCs vary in size from 1, 041 liters to 1, 325 liters and have large diameters. A round IBC with an internal diameter of 112 cm and with a cover / cover with a diameter of 1 12 cm complementary is subjected to a force of 22.4 tons against the lid under the test conditions. This enormous force requires a new technique to join and hold together the lid and body of the container. As shown in detail in Figures 5 and 6, the lid 30 and body 22 of the container are joined together in a single configuration. The upper part of the body 22 terminates in an outwardly extending flange forming an acute angle with the sealing band 48. Preferably the angle is approximately 45 °. The sealing band 48 is welded to the inner wall of the body 22 below the flange 66 and extends upwards above the height of the flange 66. The sealing band preferably extends above the flange 66 in the same way it does it down to ensure proper overlap both with the body 22 and with the cover 30. In the cover, the bottom of the cover ends with a flange 68 extending outward which forms an acute angle with the sealing band 48 when the lid is placed on the body 22. Preferably that angle is 45 °, and corresponds to the angle of the body flange. The sealing band 48 overlaps the inner surface of the lid so that internal pressures force the sealing band against the lid to minimize the pressures seen in the package 70.

When the lid 30 is placed on the body, the rim 68 of the lid is lowered to rest close to the rim 66 of the body. A gasket 70 is placed in the channel defined by the flanges 66 and 68 and the sealing band 48. The packing material is compressed by the flanges to seal the lid / body seal. Preferably the packaging is an O-ring that is made from EPDM of 40 durometers. A light film of lubricant can be placed on the flange surfaces to provide a better seal against the package 70. To keep the lid and body together, a retaining ring 34 is placed around the entire perimeter of the container against both the flange 68 of the top and flange 66 of the body. Preferably, the retaining ring is a coiled loop made of angled iron. The internal angle is placed against the rims of the lid and the body. Preferably, the ridges extend outward to a degree that complements the internal angle of the wound loop. The retaining ring is tightened around the container to further compress the lid to the body and obtain a tighter seal against the package 70. Accordingly, it is desired that the gasket 70 be large and durable enough to support the lid and keep the flanges slightly spaced before the retaining ring 34 is installed. A light film of lubricant can be used to assist the outer flange surfaces to slide across the inner surface of the retaining ring as the retaining ring is tightened. The retaining ring secures on the flanges and further compresses the packing. The retaining ring could also be a chain or cable or other strong mechanical device to obtain the same effects. Preferably, the retaining ring is a single piece having a single opening with a single fastener. However, the ring could be made from several pieces with several fasteners used to assemble it together, which could of course require additional work to install it. As shown in Figures 7, 8 and 9, the clamp clip 36 of the retaining ring is designed to hold the ends of the retaining ring together to prevent the ring from deforming inwardly and making slits in the container, or to release the internal pressure. Preferably, all the clamp clip components are made from 304 stainless steel. The clamp clip 36 is made in two complementary parts at each end 70 of the seal ring 34. On the side 72 of the head of the clamp. bolt, two parallel V-shaped plates 74 are joined along the outer rims of the retaining ring 34 starting behind the end 70 of the ring. Between the V-shaped plates 74 is a clamp block 76 extending beyond the V-cuts and slightly beyond the end 70 of the retaining ring. The block 76 can be held in place by button welds 80 through the side of the V-cuts 74. Of course, other means can be used to hold the blocks 76 in place, and the welds can be used through the clamp to secure other components together. The block 76 has a hole for a bolt 78 having a hexagonal head that fits closely between the cuts in V to prevent the bolt from turning. On the side 82 of the fastener nut, a clamp block is similarly positioned between the V-cuts 74 and held in place with button welds 80. This clamp block further extends beyond the end 70 of the clamp block. retaining ring. With this configuration, when the bolt 78 is placed through the blocks 76 and tightened with a rotatable receptacle nut 84, both the side 72 of the bolt and the side 82 of the clamp clip nut are put together until the clamp blocks 76 sit together. The clamp blocks 76 seated prevent the retainer ring from being bent inwardly by the expansive forces outwardly within the container due to any internal pressure. Therefore, the retaining ring must be of the exact dimensions to those of the specific circumference of the container. The cylindrical shape of this container is advantageous for cryogenic cleaning. Smooth round walls are easier to clean, scrape or brush. The square corners are more laborious and accumulate a greater amount of waste. In addition, a cylindrical shape requires less welding lines, which in turn means less potential to suffer thermal shock from the freeze / thaw cycles during cryogenic cleaning. The round shape can expand and contract uniformly, distributing the forces. On the other hand, it is believed that a square tank distributes non-uniform thermal shock concentrating on the corners which leads to early failure of the weld. In addition, with the cylindrical shape, the round plate bottoms and lids can be easily used to provide additional structural strength to the container, both during the freeze / thaw cycles of cleaning and during shipment with full loads. The rounded bottom plate allows easy draining of contents, but other backgrounds with different shapes could be used. The total diameter of the lid provides easy access to the interior for cleaning, compared to containers that have small inspection hole type covers. In addition, cylindrical support sleeves also provide greater force by distributing forces around the entire perimeter of the container. Conventional tanks are supported with four legs that concentrate the shocks from falls and short falls where the legs join the lower parts of the tank, often causing deformation of the tanks in that joint. With this design, the tank passed a drop test loaded with a gross weight of 2.95 tons. These advantages can be better appreciated by a description of the cryogenic cleaning system designed to clean such large volume intermediate containers.

A preferred embodiment of the system used to cryogenically clean waste from an IBC, such as the preferred embodiment described above, is shown in Figures 12 and 13. The system includes two isolated chambers. A large chamber 110 is used for cleaning the containers. A small camera 12 is used to clean the container lids. A mechanical arm / lifter 1 14 is provided to assist in the removal of the lid and its placement between the container and the large chamber 110 and the lid cleaning chamber 1 12. The cameras are preferably made of metal linings with several centimeters of insulating material between them. The metal can be mild steel, aluminum or stainless steel. Of course, non-isolated cameras can be used. However, the thermal inefficiency and waste of cryogen may not be as economical as when using isolated cameras. The large chamber 110 for the containers of preference is configured to minimize the space surrounding the container. Therefore, for a round container, a round camera would be appropriate. As best seen in Figure 13, the chamber 110 includes a recessed cryogenic sprinkler section 1 16, access doors 1 18 with hinges for placing and removing the containers and a rotating base 120. The cryogen spray section 1 16 is recessed to allow the cryogen spray to disperse and come into contact with a larger area of the container. In addition, the recessed area provides more volume for the expansion of the cryogenic gas. A plurality of sprinkler doors 122 on the vertical 124 of cryogen is located in this section. The manifolds 124 may be stainless steel tubing, copper, for example, and the doors 122 may be holes in the pipe or cryogenic spray nozzles threaded into the manifold. This spray section 1 16 preferably covers about one third of the circumference of a container in the chamber 110. The doors 118 of the chamber are opened approximately 180 degrees from the chamber to allow containers to be easily placed inside and maintain a Small space between the doors and the container after the doors close. The hinges 126 located on the outside of the door allow the total opening of the doors. Optionally, the spray doors 128 can be provided inside the doors. The doors close around the container like a jacket. The compression seals 130 are located in the upper and lower part of the door to seal it against the container. The compression seals 130 are also found in the rest of the openings in the chamber that come in contact with the container. Compression seals can be made from mylar, kevlar or silicone. It is believed that any commercially available seal designed for cryogenic applications can be used. Preferably, the compression seals will allow a modest accumulation of pressure of .0703 kg / cm2 or 0.1406 kg / cm2 inside the chamber. A pressure release system can be provided to vent any excessive pressure coming from the chamber.

A rotating base 120 is provided to rotate the container within the chamber beyond the cryogen sprinklers to provide 100% coverage of the walls of the container. The base 120 is preferably located outside the insulated chamber 110 to minimize friction and other problems such as frozen parts, resulting from exposure to cryogenic temperatures. The base includes a number of wheels 132 that follow along a rail 134. Such as one made from angled iron. As can be appreciated more easily in Figures 14 and , the base is made from an annular round support plate 136 on which the container sits. A stationary bore sleeve 138 is provided to surround the cryogen spray bore in the center of the base where the cryogen is sprayed through a set of nozzles 140 in the lower spray ring 142. The spray hole captures any liquid cryogen that has not been expanded. An inner seal sleeve 148 extends downwardly from the inner circumference of the plate 136 of the support. This rotary seal sleeve 148 concentrically overlaps the interior of the stationary bore sleeve 138 to assist in sealing the cryogen in the bore space and keep the base 120 centered and on the rails 134. Optionally, you can place a compression seal or a low temperature packing (not shown) between the seal sleeve 148 and the hole sleeve 138 to obtain a tighter seal of cryogenic gas in the hole below the container.

The base 120 is rotated by a transmission with a gear tooth / chain. Preferably, the chain 144 is located just below the plate 136 of the support, outside the hole sleeve 138. An engine, gear reducer and chain drive (not shown) could be adjusted in the annular space between the hole sleeve 138 and the wheels 132. Other means for driving the base could be used, such as, but not limited to, worm transmission, transmission with gears or transmission with bands. It is expected that the base will need to rotate around 8 to 12 rpm depending on the types of waste that need to be cleaned. Several cam follower rollers 146 extend outward from the hole sleeve 138 and support the plate 136 of the rotating base. In this way, the weight of the base is supported on the outer portion by the wheels 132, and on the inner portion by the rollers 146. As an alternative to a rotating base, a stationary base can be used. However, additional cryogen spray doors may be necessary around the entire perimeter of the container. Similarly, the chamber may need to be larger around to provide adequate distance between the doors and the container for sufficient cryogen dispersion. The chamber 1 10 of the container has an opening in the upper part configured to allow the container to extend therethrough. Ideally, the amount of container that extends above the chamber could be brought to a minimum to maintain low temperatures on all surfaces of the container. In cases where the diameter of the container is too small to be adequately sealed against the compression seals 130 located in this opening, adjustable collars (not shown) may be placed that have seals in the upper part of the chamber and placed in the chamber. against the containers to seal the camera. The chamber 12 of the lid has a similar opening at the top to allow a lid 30 to be placed with the top side down through the opening. The lid is sealed against the opening to keep cold cryogen vapor inside the chamber when it is being used. When the lid is face down, the front surface is exposed to the outside for cleaning. Within this chamber, a cryogen spray ring 150 is provided with a plurality of spray nozzles 150 directed upward toward the cap. Optionally, a central spray nozzle 152 can be supplied. The camera shown is square, but any camera shape could be adequate to clean the lid. Similarly, the chamber can be at any suitable height for a worker to easily reach and scrape, brush or vacuum clean the frozen residue. For any camera, an insulated cover could be used to cover either the container or the lid while it is in the chamber to increase the penetration of low temperature through the residue. In cases of very thick residue within the container, it may be desirable to have a cryogen spray door inside the cover to sprinkle the cryogen directly against the residue inside the container or lid.

In addition, for small containers, such as drums and pans, the cover can be used to seal the chamber, while the small container is being cooled. However, small containers will probably need to be removed for workers to clean. A work platform 154 can be provided to allow workers to stand over an open container in the chamber and clean it. The working platform can be extended both to the chamber 110 of the container and to the lid chamber 112 when the lid chamber moves to a higher position. A pedal 156 is shown on the platform. The pedal can be used to control the rotation of the base to allow workers to concentrate on specific parts of the container. The arm / lifter 114 that is used to remove the lid and place it in the chamber 112 of the lid can be activated hydraulically, pneumatically or mechanically. The arm / lifter shown is supported in a central housing 158 attached to the chamber 110 of the container. Other means for moving the lid can be provided, such as, but not limited to, overhead crane, trolley system or pulley. A number of accessories can be used with the isolated cameras. These accessories include a system of brushes and scrapers to separate the brittle residue from the surface of the container. The brushes and scrapers can be in mechanical stations that lower the brushes and scrapers towards the container to work against the residue as the container rotates on the base. In addition, a vacuum system can be used to remove the separated waste from the container. A water mist spray gun can be used to sprinkle it on the thin frozen residue in the container. The water freezes in the thin film residue and accumulates a thick layer that is easier to remove than the thin film residue itself. If it is sprinkled before the residue is cold, then the water could accumulate and run off to the bottom of the container. Preferably, soft water is used because it has a lower surface tension and penetrates better in most of the waste. In addition, you can use an air blower, desiccant-air dehumidifier system. Sometimes, the cold temperature of the container in the chamber causes a fog to form in the chamber from the warm moist ambient air that may enter as workers attempt to clean the container. This ambient air can become fog as it cools. The dehumidified cold air blown in the container would eliminate this haze and allow a clearer visibility for the cleaning of the camera. The cryogenic cleaning system can be controlled by a computer system such as a programmable logic controller (PLC). The PLC could control the action and speed of the rotating base. The PLC could control the flow rate of the cryogen sprayed in the chamber, and the location in which the cryogen is sprayed. For example, him PLC could direct the cryogen through high flow, medium flow and low flow spray nozzles, depending on the temperatures in the chamber and the thickness of the residue in the container. In addition, the PLC could direct the cryogen independently to the sides, top or bottom of the container. A temperature sensor in the chamber could be used to monitor the amount of cryogen sprayed, similar to which a thermal sensor and an infrared can measure the surface temperature of the container. The PLC can also be used for automatic shutdown of security features. For example, if the doors are opened while the cryogen is being sprayed, the spray will be turned off. Alternatively, the configured boxes, enclosures and systems are within the contemplated field of the present invention. For example, the camera can be built square so that it can be used with square IBC. Similarly, a round or square chamber could have adjustable openings and seals to clean both square and round containers. Alternatively the camera configurations can be easily designed by one skilled in the art based on the teachings described herein and on the teachings and concepts described in the U.S. Patent Application. No. 08 / 422,547, filed April 12, 1995, and Application E.U.A. No. 08 / 206,731, filed March 7, 1994, now issued as Patent E.U.A. No. 5,456,085 to James Popp and Carolyn Popp, whose content of both applications are incorporated in the present invention for reference. In addition, the teachings in these applications provide additional understanding to those skilled in the art to better appreciate the preferred methods for cryogenically cleaning the containers or for using cryogenic cleaning systems, such as those described above. However, the teachings in these applications need not necessarily be understood by one skilled in the art and be implemented in all modalities of which preferred embodiments are described herein. A preferred embodiment of the method of the present invention can be more easily described by reference to the aforementioned preferred embodiment of the apparatus. A container 20 can be cleaned cryogenically by placing the container, which has residue adhered to its surface, in an insulated box 110, removing the lid 30 with the arm / elevator and placing it in the lid chamber 112. The container can be placed in the chamber by opening the doors 118 and having a forklift to carry the container through the opening of the door and leaving the container in the upper part of the base 28. Afterwards, the doors are closed and the cold cryogen, such as that coming from a container of liquid nitrogen, is sprinkled in the chamber 110 insulated so as to contact and cool the body 22 of the container and the residue. The rotating base is preferably switched before spraying so that the container is completely covered with the cryogen and uniformly applied to avoid thermal shock. The residue will become brittle and will fragment and can be separated from the surface by scraping or brushing the residue from the surface of the body of the container. In some situations, the container may need to be struck or vibration applied to loosen the residue that adheres strongly. The waste is removed after the container through a vacuum hose to a waste receptacle leaving a container substantially free of waste. After the residue is removed, the container is removed from the insulated case 110. A liquid cryogen, such as liquid nitrogen at 1.5466 kg / cm 2, is preferably used and introduced into the open space between the walls and the container. A cryogen pump can be used to maintain 1.5466 kg / cm2 in the supply line. As liquid nitrogen penetrates this area and comes into contact with the warm area and the warm IBC, liquid nitrogen expands into a gas and lowers the temperature inside the equipment and the IBC itself to temperatures as low as -184.4 ° C. The exact temperature and the amount of time required is based on the type and amount of waste that is being removed from the IBC. The thermal dynamic reaction between the contraction of the IBC metal and the expansion of the residue material that is being removed results in breaking the bond between the IBC and the residue. The frozen residue can then be scraped, brushed and / or beaten and removed by shoveling and / or vacuuming the brittle and separated residue. There are some residues that may require only shoveling or vacuum application without being scraped, without brushing or hitting. The container, if light enough, can be removed and turned downward for the removal of the fragmented and separated residue, although this is not the preferred method. The present invention can be applied to clean a wide variety of product residues issued from product containers. These residues include, but are not limited to, tars, lubricants, mastics, inks, coatings, solvents, adhesives, glues, sealants, varnishes, paints, paint pigments, lacquers, resins, plasticized materials, greases, cement materials, etc. The waste may also be consumable, ie, articles of commercial products such as molasses, honey, corn syrup, apple syrup and the like. The present invention can be applied to containers that have a combination of different residues adhered to their surface. The waste can be fresh, that is, in its commonly useful, liquid, viscous or sticky form. In addition, the waste may have a dry surface film. In addition, the present invention can be applied to waste that has dried, solidified or cooked. Generally, the present invention works rapidly with the waste that very thinly covers the surface of the container, but is also effective where the waste is several centimeters thick, or larger. Typically, the present invention is directed toward cleaning the internal surfaces of the containers, but, as will become apparent from this detailed description, it may also clean the exterior surfaces. The present invention can be applied to containers of products made from metal, plastic, polymers, resins or a mixed material of different materials. For example, some wastes can become brittle at temperatures of only -50 °, while plastic containers made from HDPE need to be cooled to -155 ° C to become brittle to the point where the container can be permanently damaged The present invention can substantially remove the waste from the container so that the container can be reused, meet governmental requirements for the disposal of non-hazardous waste, or be further cooled to the point of embrittlement so that the containers can be crushed to reduce its volume to be discarded. The containers preferably vary in sizes between about 322 liters and about 1325 liters. The method of the preferred embodiment is particularly well suited for commonly used intermediate volume containers of 122 to 1325 liters by volume. Preferably the containers have a substantially cylindrical shape with a full opening at one end. The residue can be more easily removed from such a container, but the present invention can be effective in other containers, such as those having narrow corners and a small opening.

Cryogens are generally gases that have a very low boiling point. Nitrogen (N2), for example, has a boiling point of -195 ° C at atmospheric pressure. Cryogens can be easily stored as a liquid in specially designed storage tanks. A range of liquid cryogens, or cryogenic agents, or cryogenic gases that theoretically could be used with the present invention are commercially available. These include, but are not limited to, nitrogen, helium, argon and carbon dioxide. However, some cryogenic gases are flammable or require extreme precautions and equipment to be used safely and therefore are not preferred. Nitrogen is a preferred cryogen due to its relative safety when used and its low cost. Nitrogen is an inert gas that is non-flammable, non-toxic and does not present a risk of reaction with the waste or equipment materials. Nitrogen is the largest constituent of air so that it can be dissipated safely in the environment. Special safety equipment is not required when using nitrogen cryogen with the present invention, apart from other minor protective equipment for cold temperatures. However, a well ventilated and large room is preferred to use the present invention to avoid the lack of oxygen caused by the vaporized nitrogen cryogen that displaces the air in the room. The cooling time and the operating temperature are interdependent. The residue is not required to cool to the selected operating temperature. In contrast, lower temperatures will result in faster heat transfer speeds and in the reduction of the amount of time required to make the residue brittle. In this way, economic trade-offs are involved in the selection of the operating temperature. Lower temperatures and shorter cooling times will require the use of more cryogen. On the other hand, higher temperatures and longer cooling periods will correspondingly increase labor costs. Subject to the above, for most applications, lower temperatures and faster cooling times are preferred. This can be achieved by introducing sufficient cold vaporized cryogen into the box 10 insulated with a container inside to maintain a temperature between -75 ° C and about -185 ° C. Preferably, the temperature will be maintained between -100 ° C and close to -155 ° C. During the cooling step, as the temperature in the box rises above its desired value, more cryogen should be introduced to lower the return temperature to the desired value. This can be achieved through the use of an automatic temperature controller or a PLC to regulate a cryogenic control valve. Maintaining the internal medium of the insulated box within the most preferred temperature range for a period of about 4 to 6 minutes will be sufficient to make the thin coatings brittle of the majority of the waste. Of course, this time may vary depending on several factors. Thick layers of residue will require more cooling time. For example, a 15 cm thick layer of a coating material will require up to about 15 to 20 minutes of treatment time. In some situations, for example when the waste is difficult to remove, the container can be subjected to thermal cycles. The container can be cooled, then heated and then cooled again.

It is believed that the different rates of shrinkage and expansion of the waste and the container can cause the waste to be released from the surface of the container through successive temperature cycles. In this sense, it might be desirable to apply steam to the waste to heat it faster than to the container, thus exaggerating the temperature differences. Similarly, it is believed that the moisture coming from the steam could penetrate the waste and the surface of the container, which upon cooling, will freeze, expand and burst the waste off the surface of the container. For certain residues, the use of a mold release agent could be desired. For example, the paint used to paint the lines on the roads is made so that it adheres to the surface of the road in a range of climatic extremes. This property also makes it particularly difficult to remove it from the containers, even using cryogenic temperatures. It has been discovered that this road surface paint can be more easily removed from the containers if a mold release agent is sprinkled onto the inside surface of the clean container before the paint is loaded into the container. Even highly polished container surfaces can have micro-sized pores on the surface to which the residue can cling tenaciously. It is believed that the mold releasing agent fills these pores to prevent the residue from penetrating and binding to the container. The agent is typically sprayed on the clean surface and allowed to dry in a 1-2 micron thin layer that resists mixing with the material of the product being loaded into the container. The release agent must be formulated especially for the particular product to be transported in the container. The company Chemlease International, Inc., of Lake Mary, Florida USA, has such commercially available mold release agents and can formulate in a special manner agents for a wide variety of products and container materials. In some situations, such as those in which the waste is a thin layer, it could be difficult to efficiently remove all the waste. One reason for this could be that the thin residue does not have enough mass and internal resistance to separate from the container in large fragments. This could be compared to the removal of ice from a car windshield, that is, by comparing the removal of a layer of snow and a thick sheet of ice. This situation could occur for thin waste, such as those that are less than 6 millimeters thick. To improve the efficiency of the method described above, a thermal retention mass can be adhered to the waste before the waste is cryogenically brittle. By the term "thermal retention mass" is meant a mass or volume of material sufficient to retain the cold embrittlement temperatures for a sufficient period after the container has been removed from the cryogenic environment so that the residue remains brittle and can be fragmented by hitting the container.

Furthermore, it is believed that the weight coming from the adhering thermal retention mass also helps to separate the residue from the surface of the container, either by scraping, brushing, beating or vibrating. In addition, it is expected that a thermal mass with a high heat transfer rate could increase the speed at which the waste cools. This thermal mass could be a granular material with a size between 0.13mm and 0.89mm. When the waste is a consumable food product, it may be preferable to use a consumable thermal mass so that the waste and thermal mass can be recycled together as an animal food product. Some of these granulated materials may be, but are not limited to, salt, sugar, sand, corn granulates, bean granules, aluminum oxide, clay pellets, oil absorbing pellets, "oil-dri", rubber granulates. , granules of plastic material, fibers in pieces, pieces of wood pieces of stone, slag from steelmaking, granulated materials of cork, granulated metals, granulated glass or coal granules. The choice of what type of granulated material will be used with what waste will depend on many factors including cost, the subsequent use of the waste, the compatibility or inertness of the granular material with the residue, the adhesion capacity of the material granulated to the residue, the restrictions for its elimination, etc. For example, a granular absorbent "oil-dry" material was effective in aiding the removal of a thin film of resin-based adhesive from a cylindrical drum. The granulated materials can be applied manually, sprinkled, rolled, applied before the container is placed in the cryogenic treatment enclosure, applied inside the enclosure, or applied simultaneously with the injection of cryogen. Granulated materials adhere more easily to a wet, sticky or viscous residue. There is a possibility that the granulated materials are mixed with a resin, or other material, so that they could adhere to the dry residues. In addition, the granulated materials could be mixed with a liquid and sprinkled on the frozen residue. In addition to the granulated form, the thermal retention mass could also be of fibrous or viscous consistency. The fibrous mass can adhere to the residue to form a membrane, or tapestry. The fibers can be pulled out of the container and pulled with the brittle residue. Such fibrous masses could include fiberglass or cloth strips, rag yarns, polyester yarns, wood shavings, cotton tow or cloth waste, for example.

A viscous thermal mass could also be used. For example, molasses, resins or mastics can be applied to the waste to accumulate its layer to a critical mass sufficient to retain its fragility after removing it from the cryogenic treatment enclosure. Even when the residue is in dry form, a sticky or viscous material can easily adhere to form a heavy heavy thermal retention layer on the surface of the container so that it can be easily treated in accordance with the method of the present invention. Other materials such as water, gels or foam may also find some use in this application. The advantages of the preferred embodiments are numerous. Preferred embodiments avoid the use of solvents and other wash liquids associated with traditional cleaning methods so that the amount of hazardous material to be disposed of is limited to the original waste itself. In addition, the waste can be recycled or reused as it is not contaminated by washing liquids or solvents. The methods described require less equipment and less work to operate than traditional cleaning methods and reduce health risks for employees. The methods described are more economical than traditional cleaning methods. The preferred embodiments substantially remove the waste from the container to meet the governmental disposal requirements and the industrial requirements for the reuse or recycling of the container.

It should be appreciated that the methods and apparatus of the present invention allow to be incorporated in the form of a variety of modalities, of which only a few have been illustrated and described above. The invention can be modalized in other forms without departing from its essence or essential characteristics. For example, the container can be a mixed material made with an outer layer of plastic or fiberglass and a metal lining. The metallic lining could be easily removed and cleaned cryogenically. The plastic and fiberglass type container could be lighter in weight and less expensive than a full metal container. In addition, plastic and fiberglass containers do not have to pass astringent tests as do metal tanks. The described embodiments should be considered in all respects only as illustrative and not restrictive, and the scope of the invention is therefore indicated by the appended claims rather than by the foregoing description. All changes that arise within the meaning and range of equivalence of the claims should be encompassed within their field.

Claims (31)

NOVELTY OF THE INVENTION CLAIMS

1. - An apparatus for cryogenically treating containers consisting of an insulated box having an opening in the upper part of the box large enough to allow the placement and removal of a container from one side to the other of the same, a collar adapted to surround a container placed through the opening characterized in that the collar has a width extending from the outside of the container to the perimeter of the opening to seal the opening, and a plurality of cryogen spray doors in the box.

2. The apparatus according to claim 1, further characterized in that the collar is slidably positioned on a surface of the upper part of the insulated box, the collar being composed of a plurality of sections having a flexible packing on the inner face to form a seal against the container when placed against the container.

3. The apparatus according to claim 1, further characterized in that it consists of a second opening in the upper part of the box large enough to allow the placement and removal of a lid of the container from one side to another thereof and a door to seal the second opening.

4. - An apparatus for cryogenically treating containers consisting of a first insulated chamber having an opening in the upper part of the chamber large enough to allow a container to extend from one side to the other of the same, the opening having a packing for sealing a container, the chamber additionally having a side door to allow placement of a container from one side to another thereof, a base to support a container, and a plurality of cryogen spray doors of the chamber, characterized in that the Sprinkler doors are located on the wall of the chamber along at least one third of the perimeter of the chamber separated to sprinkle the height of a container in the chamber, and located above the base to sprinkle the bottom of a container .

5. The camera according to claim 4, further characterized in that the base rotates allowing a container to settle on it to rotate beyond the spray doors located on the wall of the chamber.

6. The chamber according to claim 4, further characterized in that the opening has an adjustable collar that slides to place the package against the container.

7. The apparatus according to claim 4, further characterized in that it comprises a second chamber adapted to receive a lid of a container placed in the first chamber, and a lifting arm to remove and place the lid from the container and place the lid in the second chamber.

8. The apparatus according to claim 5, further characterized in that it comprises retractable scrapers adapted to scrape the interior of the container as it rotates.

9. The apparatus according to claim 5, further characterized in that it consists of a working platform near the top of the first chamber, further characterized in that the work platform has a switch to control the rotating base.

10. The apparatus according to claim 4, further characterized in that it consists of a vacuum system with nozzles adapted to remove the debris from inside the container inside the first chamber.

11. The apparatus according to claim 4, further characterized in that it comprises a dehumidifier and an air blowing system positioned to place dry air inside a container inside the first chamber.

12. A container of products consisting of: (a) a cylindrical body having an upper end and a lower end, the lower end being closed by a bottom, and the upper end being open with a flange of the body extending outward at the upper end that forms an obtuse angle with the body; (b) a lid having a cylindrical side wall that depends on the lid with the side wall ending with an outwardly extending lid lip that forms an obtuse angle with the side wall, further characterized by the lid being seated by on top of the open end of the section of the cylindrical body with the cap flange near the body flange; (c) an internal sealing band radially inward of the body flange and lid rim, the sealing band extending from a height above the top portion of the lid rim to a height below the body rim overlapping the inside of the side wall of the cap and the cylindrical body, further characterized in that the flanges and the sealing band form an acute angle; (d) a sealing gasket placed in the channel defined by the internal sealing band, the body flange and the cap flange; and (e) a retaining ring that surrounds the perimeters of the body rim and the rim of the cap, the ring being adapted to apply a force against the body rim and the cap rim to seal against the packaging.

13. The container according to claim 12, further characterized in that it comprises a cylindrical external support jacket that depends on the outside of the lower end of the body and an internal cylindrical support jacket that depends on the bottom of the body.

14. The container according to claim 13, further characterized in that the internal cylindrical support jacket has a plurality of openings.

15. - The container according to claim 13, further characterized in that it consists of an outlet tube with one end connected to the center of the bottom and the other end passing through an opening in the internal support jacket.

16. The container according to claim 13, further characterized in that it consists of a base below the support jacket where the base has two separate elevator cavities apart parallel along a first direction of the base and two parallel spaced cavities along a second direction perpendicular to the first direction.

17. The container according to claim 12, further characterized in that the retaining ring consists of an angled loop wherein the internal angle of the loop is complemented by the angle formed by the close position of the body flange and the flange of the body. the lid.

18. The container according to claim 12, further characterized in that the retaining ring is held tight against the shoulders by at least one clamp clip, wherein the clamp clip includes two parallel lateral V-shaped cuts. which extend from the loop close to each end with each set of V-cuts sandwiching a clamp block between them with the blocks that sit one against the other and a bolt passing through each clamp block and a nut to hold the bolt to hold the clamp blocks against each other and the loop against the flanges.

19. The container according to claim 12, further characterized in that the upper end of the body of the container is substantially open to the maximum diameter of the container.

20. The container according to claim 12, further characterized in that the internal sealing band is attached to the interior of the cylindrical body near the body rim.

21. A container of products consisting of: (a) a cylindrical body having an upper end and a lower end, the lower end being closed with a bottom with an exit door at the bottom to remove the contents in the container, the upper end being open with a flange of the body extending outwardly at the upper end; (b) a lid having a cylindrical side wall that depends on the lid with the side wall ending with a lid edge extending outwardly, where the lid sits above the open end of the cylindrical body section with the cap flange close to the body flange; (c) an internal sealing band radially inward from the rim on the body and the lid rim, the sealing band extending from a height above the top of the rim of the lid to a height below the rim of the body overlapping the inside of the side wall of the cap and of the cylindrical body, wherein the flange and the sealing band define a packing channel; and (d) a seal package placed in the packing channel.

22. The container according to claim 21, further characterized in that it comprises a cylindrical external support jacket that depends on the exterior of the lower end of the body and a cylindrical internal support jacket that depends on the bottom of the body.

23. The container according to claim 22, further characterized in that the cylindrical internal support sleeve has a plurality of openings.

24. The container according to claim 21, further characterized in that the outlet has a door that is placed horizontally.

25. The container according to claim 21, further characterized in that a base below the support jacket has two cavities for separate spaced-apart elevators along a first direction of the base.

26.- The container according to claim 25, further characterized in that the base additionally consists of two separate elevator cavities parallel along a second direction perpendicular to the first direction.

27. The container according to claim 21, further characterized in that the upper end of the body of the container is substantially open to the maximum diameter of the container.

28. - The container according to claim 21, further characterized in that the internal sealing band is attached to the interior of the cylindrical body near the body rim.

29. The container according to claim 21, further characterized in that the lid is forced towards the cylindrical body to compress the packing between the rim of the lid, the rim of the body and the sealing band.

30.- A container of products consisting of: (a) a cylindrical body having a lower end, a cylindrical side wall extending from the lower end, and an upper end, the lower end being closed by a bottom with a exit door to remove the contents of the container; (b) an outwardly extending body flange positioned at the upper end of the body to form an obtuse angle with the side wall of the body below the body flange; (c) a cap having an upper end, a cylindrical side wall depending on the upper end and a lower end, wherein the cap is adapted to settle over the upper end of the cylindrical body to thereby close the container; (d) a rim of the outwardly extending cap positioned at the lower end of the cap to form an obtuse angle with the side wall of the cap above the rim of the cap, wherein the rim of the cap is close to the rim of the body when the lid is placed on the body; (e) an internal sealing band positioned radially inward of the body rim and the rim of the lid extending the sealing band from a height above the rim of the lid at a height below the rim of the body when the lid is placed on the body, further characterized in that the flange of the body and the flange of the cap are each placed at an acute angle with respect to the sealing band and the flanges and wherein the sealing band defines a packing channel; and (f) A sealing gasket placed in the packing channel, the package being compressed between and in contact with the lid flange, the body flange and the sealing band when the lid is placed on the body.

31. The container according to claim 21, further characterized in that the lower end of the body has a rounded plate shape and the upper end of the lid has a rounded plate shape.