Compositions – Vaporization – or expansion – refrigeration or heat or energy... – With lubricants – or warning – stabilizing or anti-corrosion...
Reexamination Certificate
1998-10-09
2001-02-06
Skane, Christine (Department: 1751)
Compositions
Vaporization, or expansion, refrigeration or heat or energy...
With lubricants, or warning, stabilizing or anti-corrosion...
C252S964000, C073S040700
Reexamination Certificate
active
06183663
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention relates to a leak detection dye delivery system for introducing a leak detection dye composition into a climate control system.
Leak detection methods have been developed to analyze fluid systems, such as climate control systems, i.e., heating, cooling, ventilating, and air conditioning systems, using dyes. Some methods employ emissive substances, such as, for example, fluorescent or phosphorescent dyes that are added to the refrigerants and/or lubricants of a climate control system. Suitable leak detection dyes include naphthalimide, perylene, thioxanthane, coumarin, or fluorescein, and derivatives thereof.
Leaks can be detected by observing fluorescence of the dye at leak sites resulting from excitation of the dye with a light source having particular illumination characteristics. For example, suitable light sources for use in fluorescence detection transmit light of wavelengths suitable to excite the dye and cause light emission from the dye. In general, the dyes emit brightly when excited by light in the 190 to 700 nanometer wavelength range.
SUMMARY OF THE INVENTION
In general, the invention features a leak detection delivery system for introducing a leak detection dye into a climate control system. The leak detection dye delivery system includes a canister loaded with a dye concentrate, a lubricant, and a refrigerant.
In one aspect, the invention features a leak detection dye composition including a refrigerant, a lubricant, and a dye concentrate. The dye concentrate includes a fluorescent dye. The leak detection dye composition contains less than 50 percent by weight of the refrigerant.
The leak detection dye composition can include, for example, a first weight amount of the dye concentrate and a second weight amount of the refrigerant. The first weight amount can be greater than the second weight amount. In other embodiments, the leak detection dye composition can include, for example, a first weight amount of the dye concentrate, a second amount of the lubricant, and a third amount of the refrigerant. The first amount and the second amount, together, can be greater than the third amount.
The fluorescent dye is dissolved in the leak detection composition remains dissolved in the leak detection composition after 5 days at −10° C. Alternatively, the leak detection dye remains dissolved in the leak detection composition after 30 days at −10° C. The dye is dissolved and remains dissolved in the composition when the dye does not crystalize from the composition (i.e., the dye concentration remains below its solubility limit in the composition).
In another aspect, the invention features a leak detection dye delivery system including a canister containing a leak detection composition.
In another aspect, the invention features a method of manufacturing a leak detection dye delivery system. The method includes loading a canister with a lubricant, and a dye concentrate including a fluorescent dye. After loading, the canister includes a leak detection dye composition including a refrigerant, the dye concentrate, and the lubricant. The refrigerant can be introduced into the canister after loading the canister with the lubricant and the dye concentrate. The lubricant and the dye concentrate can be combined before loading the canister.
The canister can have a volume of less than about 5 ounces, preferably less than about 4 ounces, and more preferably less than about 3 ounces. For example, the canister volume can be between 2 and 2.5 ounces. The leak detection composition can contain less than 50 percent by weight of the refrigerant. The leak detection composition also can include a first weight amount of the dye concentrate and a second weight amount of the refrigerant, the first weight amount being greater than the second weight amount.
In yet another aspect, the invention features a method of introducing a leak detection dye into a climate control system including discharging into the climate control system a leak detection composition having a refrigerant, a lubricant, and a dye concentrate. The leak detection composition can be discharged from a canister into the climate control system. The climate control system can be an air conditioning system.
The refrigerant can include chlorofluorocarbons, hydrochlorofluorocarbons, hydrofluorocarbons, carbon dioxide, ammonia, halogenated or ether derivatives of methane or ethane, or halogenated ether or cyclic derivatives of propane, butane, pentane, or other hydrocarbons. The lubricant can include polyalkylene glycols, polyolesters, mineral oils, polyvinyl ethers, alkylbenzenes, or other synthetic lubricating materials.
The dye concentrate includes a leak detection dye such as a fluorescent dye. The fluorescent dye can include a naphthalimide, a perylene, a coumarin, a thioxanthane, a fluorescein, or a derivative thereof, or other dye compatible with climate control system. The fluorescent dye can be a liquid or a solid, such as a powder.
The leak detection dye delivery system is compact, making it easy to handle and use. The leak detection delivery system also can be used to deliver more consistent amounts of a leak detection dye into a climate control system. The delivery of dye can be more efficient as well. For example, the leak detection dye remains dissolved in the leak detection composition so that during shipping or storage the leak detection dye does not crystalize out of the composition, which can change the concentration of the leak detection dye which enters the system. By remaining dissolved, the leak detection dye does not form crystals while standing; the dye is completely soluble in the composition at a particular temperature for a particular amount of time. The small volume of the leak detection dye composition used in the leak detection dye delivery system reduces the amount of extraneous materials (e.g., dye, lubricant, and refrigerant) introduced into a climate control system.
The climate control system can be a mobile, stationary, window air conditioning system such as an automotive, portable, residential, or commercial air conditioning system, or any other hermetic system that employs a refrigerant and lubricant.
Additional features and advantages of the invention will become apparent from the detailed description of the preferred embodiments of the invention.
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Cavestri Richard C.
Kalley Terrence D.
Bright Solutions Inc.
Fish & Richardson P.C.
Skane Christine
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