Refrigeration – Hand manipulable tool
Reexamination Certificate
2000-05-02
2001-09-11
Tapolcai, William E. (Department: 3744)
Refrigeration
Hand manipulable tool
Reexamination Certificate
active
06286329
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to an apparatus for freezing a plug of frozen liquid in a liquid-filled pipe, to plug said pipe at a point where there is no conventional valve, so that pipe repairs can be performed downstream of the plug.
BACKGROUND ART
PIPE FREEZERS USING EXPENDABLE REFRIGERANTS
A pipe freezer works by removing heat quickly enough from the liquid within a section of pipe that an ice plug forms in that section of pipe, thus effectively preventing the flow of liquid through that section of pipe. This ice plug acts as a temporary valve. When the ice plug is properly maintained (kept frozen), repairs can be performed on the pipe in the vicinity of the ice plug without the need to drain the piping system.
TWO PRIMARY METHODS OF FREEZING PIPES
1. Expendable refrigerants sprayed directly onto the pipe and vented to the atmosphere.
2. Compression cycle refrigeration, which circulates the same refrigerant in a closed loop as a refrigerator does.
1. Expendable refrigerants: These are the traditional refrigerants for freezing the contents (in a small section of pipe 5.08 cm-25.4 cm (2 in-10 in) in length) within plumbing piping or other fluid carrying conduits with a liquid that will freeze within the temperature range of the refrigerant being used.
The three more commonly used expendable refrigerants are listed below with their refrigerant number and boiling point at sea level (14.7 PSIA).
1. Liquid Carbon Dioxide: R744, −109 F. (−78 C)
2. Liquid Nitrogen: R728, −320 F. (−196 C)
3. Liquid Helium: R707, −425 F. (−269 C)
On pipes up to three 7.62 cm (three inches) of inner diameter the refrigerant of choice is carbon dioxide. There are five or more kits using carbon dioxide currently on the market in the US. Liquid nitrogen and liquid helium are not as available, are only packaged in large containers, and require additional safety training. There are companies that specialize in pipe freezing of pipes up to 152.4 cm (60 in) inside diameter. On pipes this large, liquid nitrogen or liquid helium would be used depending upon the application.
The current expendable refrigerant pipe freezing kits (for pipes up to 7.62 cm (3 in) ID) employ bags or collars that wrap around the pipe. The collars are hinged on one side and have a locking screw. The bags are wrapped around the pipe and tied on each end. Each type of kit has a spray head, which sprays the refrigerant over the pipe. A high-pressure hose delivers the liquid refrigerant to the spray heads from the tank.
As the liquid refrigerant is sprayed over the pipe within the bag or collar, dry ice is being formed due to the containment of the refrigerant (i.e., the refrigerant is not allowed to fully evaporate into the atmosphere). When enough dry ice is formed, the refrigerant valve on the tank is closed stopping the flow of refrigerant in to the bag or collar. To conserve refrigerant, heat is now removed from the pipe through the dry ice. The ability of the dry ice to remove heat from the pipe is much less than that of the denser liquid refrigerant. Throughout the process, the liquid refrigerant is turned on and off to conserve refrigerant, while depending on the dry ice, which was formed, to remove heat from the pipe.
Draw backs of free flow systems over Applicant's Multi-Cavity Adapter /Cartridge Evaporator
1. Requires longer freeze times.
2. Consumes more refrigerant
3. Cannot control vented gas location
4. Cost of equipment.
5. Danger of hose failure due to cold bending.
DESCRIPTION OF RELATED ART INCLUDING INFORMATION DISCLOSED UNDER 37 CFR 1.97 AND 37 CFR 1.98.
The present inventor invented U.S. Pat. No. 4,309,875 issued to Radichio Jan. 12, 1982 for a Pipe Freezer or the Like, in which a self contained freezing device forms a plug of ice within a pipe section. A refrigeration unit supplies refrigerant to a cradle-like freezer unit within which the section of pipe to be frozen is held in spaced relation to the inner face of the freezer. The space between the underside of the pipe and the inner face of the freezer is filled with water, for example, by spraying. As the water in contact with the cradle-like freezer unit freezes, it covers the outer surface of the pipe section with an ice jacket. Alternatively, a bag of freezable gel may be substituted for the water spray and placed over the inside face of the freezer; and then the pipe section is placed within the fold of the bag. In the case of either alternative, the refrigerant is maintained inside the freezer, and out of contact with the pipe.
My U.S. Pat. No. 5,548,965 to Chen and Radichio issued on Aug. 27, 1996 for a Multi-cavity Evaporator which has an outer surface and an inner chamber. The outer surface has at least two pipe receiving surfaces and a pair of ends. The evaporator has a bore extending from one of the ends to the inner chamber. A tube extends into the bore sealing the chamber, such that a refrigerant flows into the inner chamber through an inner tube and out of the inner chamber through the outer tube. Each of the pipe receiving surfaces has a distinct surface adapted for receiving different size pipes.
BRIEF SUMMARY OF THE INVENTION.
The present invention uses a multi-cavity adapter having from two to eight cavities to fit standard plumbing pipes in copper, steel and plastic, metric and US standard. The refrigeration evaporator fits into a cylindrical bore in the core of the radial multi-cavity array. The cavities are arrayed around the circumference of the bore. The extrusion that forms the array is of aluminum or the like.
The coolant lines are elbowed at 90 degrees to the evaporator's longitudinal axis to facilitate attachment to pipes in small or tight spaces and from the side of the pipes. The central bore in the adapter body has a diameter slightly larger than the diameter of the evaporator which allows the evaporator to swivel freely in the adapter body thus minimizing wear and tear on the refrigeration lines to the evaporator when the evaporator is inserted into the central bore of an adapter body of the multi cavity adapter. Any of the cavities on the adapter body can be lined up with the pipe. When a single adapter is being used, the adapter is positioned on the pipe and secured with a strap having hook and loop fastening material. Then the cartridge evaporator is plugged into the adapter.
More preferably two units, a unit on either side of the pipe, are strapped in place to fully surround the pipe. Most preferably a special set of adjustable retainer mechanisms is used to tightly secure the adapters to the section of pipe to be frozen.
REFERENCES:
patent: 3559423 (1971-02-01), Scheidler
patent: 3742723 (1973-07-01), Grisé
patent: 4309875 (1982-01-01), Radichio
patent: 4433556 (1984-02-01), Brady
patent: 4441328 (1984-04-01), Brister
patent: 4944161 (1990-07-01), VanDerSanden
patent: 5548965 (1996-08-01), Chen et al.
patent: 5680770 (1997-10-01), Hall et al.
patent: 5836167 (1998-11-01), Clouston et al.
patent: 0145114B1 (1984-02-01), None
patent: WO89/01110 (1988-06-01), None
Econo Freeze portable CO2 pipe freezing equipment, Econo Freeze, Antioch, IL 60002.
The Advantages of Freezing a Pipe, Econo Freeze, Antioch, IL 60002.
The Savair Pipe Freezer, Don't Drain, Just Freeze, Spirotherm Inc., Glendale Heights. IL. 60139-2067.
Fitzpatrick Michael D.
Tapolcai William E.
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