Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B08—CLEANING
  • B08B—CLEANING IN GENERAL; PREVENTION OF FOULING IN GENERAL
  • B08B9/00—Cleaning hollow articles by methods or apparatus specially adapted thereto
  • B08B9/02—Cleaning pipes or tubes or systems of pipes or tubes
  • B08B9/027—Cleaning the internal surfaces; Removal of blockages
  • B08B9/032—Cleaning the internal surfaces; Removal of blockages by the mechanical action of a moving fluid, e.g. by flushing
  • B08B9/0321—Cleaning the internal surfaces; Removal of blockages by the mechanical action of a moving fluid, e.g. by flushing using pressurised, pulsating or purging fluid
  • B08B9/0325—Control mechanisms therefor
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B08—CLEANING
  • B08B—CLEANING IN GENERAL; PREVENTION OF FOULING IN GENERAL
  • B08B7/00—Cleaning by methods not provided for in a single other subclass or a single group in this subclass
  • B08B7/0021—Cleaning by methods not provided for in a single other subclass or a single group in this subclass by liquid gases or supercritical fluids
• • C—CHEMISTRY; METALLURGY
  • C11—ANIMAL OR VEGETABLE OILS, FATS, FATTY SUBSTANCES OR WAXES; FATTY ACIDS THEREFROM; DETERGENTS; CANDLES
  • C11D—DETERGENT COMPOSITIONS; USE OF SINGLE SUBSTANCES AS DETERGENTS; SOAP OR SOAP-MAKING; RESIN SOAPS; RECOVERY OF GLYCEROL
  • C11D7/00—Compositions of detergents based essentially on non-surface-active compounds
  • C11D7/22—Organic compounds
  • C11D7/28—Organic compounds containing halogen
  • C11D7/30—Halogenated hydrocarbons
• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23G—CLEANING OR DE-GREASING OF METALLIC MATERIAL BY CHEMICAL METHODS OTHER THAN ELECTROLYSIS
  • C23G5/00—Cleaning or de-greasing metallic material by other methods; Apparatus for cleaning or de-greasing metallic material with organic solvents
  • C23G5/02—Cleaning or de-greasing metallic material by other methods; Apparatus for cleaning or de-greasing metallic material with organic solvents using organic solvents
• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23G—CLEANING OR DE-GREASING OF METALLIC MATERIAL BY CHEMICAL METHODS OTHER THAN ELECTROLYSIS
  • C23G5/00—Cleaning or de-greasing metallic material by other methods; Apparatus for cleaning or de-greasing metallic material with organic solvents
  • C23G5/02—Cleaning or de-greasing metallic material by other methods; Apparatus for cleaning or de-greasing metallic material with organic solvents using organic solvents
  • C23G5/028—Cleaning or de-greasing metallic material by other methods; Apparatus for cleaning or de-greasing metallic material with organic solvents using organic solvents containing halogenated hydrocarbons
  • C23G5/02803—Cleaning or de-greasing metallic material by other methods; Apparatus for cleaning or de-greasing metallic material with organic solvents using organic solvents containing halogenated hydrocarbons containing fluorine
• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23G—CLEANING OR DE-GREASING OF METALLIC MATERIAL BY CHEMICAL METHODS OTHER THAN ELECTROLYSIS
  • C23G5/00—Cleaning or de-greasing metallic material by other methods; Apparatus for cleaning or de-greasing metallic material with organic solvents
  • C23G5/02—Cleaning or de-greasing metallic material by other methods; Apparatus for cleaning or de-greasing metallic material with organic solvents using organic solvents
  • C23G5/04—Apparatus
• • C—CHEMISTRY; METALLURGY
  • C11—ANIMAL OR VEGETABLE OILS, FATS, FATTY SUBSTANCES OR WAXES; FATTY ACIDS THEREFROM; DETERGENTS; CANDLES
  • C11D—DETERGENT COMPOSITIONS; USE OF SINGLE SUBSTANCES AS DETERGENTS; SOAP OR SOAP-MAKING; RESIN SOAPS; RECOVERY OF GLYCEROL
  • C11D2111/00—Cleaning compositions characterised by the objects to be cleaned; Cleaning compositions characterised by non-standard cleaning or washing processes
  • C11D2111/10—Objects to be cleaned
  • C11D2111/14—Hard surfaces
  • C11D2111/20—Industrial or commercial equipment, e.g. reactors, tubes or engines

Definitions

• the present application relates to systems for cleaning refrigeration systems such as air conditioning systems, and more particularly to a system for flushing contamination from such a system.
• Air conditioning and refrigeration equipment can suffer from catastrophic failures such as compressor motor burnout. These failures may create contaminants within the sealed system which can include acids, sludges and particulates.
• the heat exchangers or other components in such systems are usually flushed with a solvent to remove the contaminants.
• the solvent of choice was R11.
• the present invention provides a method for cleaning a component of an air-conditioning or refrigeration system that cleans and recycles the solvent as it is being used.
• the invention provides for flushing liquid solvent through the air-conditioning component to remove contamination from the component.
• the solvent having picked up the contamination, is then vaporized, followed by the removal of the contamination from the vaporized solvent so as to clean the solvent of the contamination.
• the cleaned solvent is then liquefied and recycled for use again in flushing the component.
• the solvent is continuously cleaned and reused for flushing without the solvent becoming more and more contaminated with each use.
• the solvent left over in the component can be recovered and the contamination which has been separated out of the solvent purged for disposal.
• An apparatus for carrying the above method is also provided.
• FIG. 1 is a schematic diagram of a flushing machine for air conditioning and refrigeration devices.
• the present invention provides a method and apparatus for flushing air conditioning and refrigeration systems and components, and will be described with reference to Figure 1.
• the invention is carried out with an apparatus 10, as shown within the dotted lines, that delivers solvent from a closed supply tank 12 to an air conditioning component 14 to be cleaned.
• the solvent picks up dissolved oil and other contaminants (referred to collectively as the "oil") and then passes to other parts of the apparatus 10 where the solvent is cleaned of the contaminants and ultimately returned to the source tank 12 for further use.
• the method of the present invention is a multi-cycle system for carrying out at least the following: cleaning the component 14, purging the contamination collected by the solvent, and recovering the clean solvent for reuse.
• a component 14 of an air conditioning system (the other components of the air conditioning system not shown) is cleaned of contaminants.
• the component 14 could be a condenser or heat exchanger from an air-conditioning or refrigeration unit in which the compressor motor burned out, overheating the oil in the compressor and creating contaminants.
• the component 14 is usually disconnected from the remainder of the air-conditioning system (fluidly disconnected, not necessarily removed from its mount in the engine compartment for example) so that it can be fluidly connected to the apparatus 10.
• various connected components of the air-conditioning system or the entire system can be connected to the apparatus 10.
• the solvent to be used for cleaning the component is preferably a hydrofluorocarbon (HFC), such as HFC-245fa, which is stored in the source tank 12.
• HFC hydrofluorocarbon
• a tank 12 holding between 1 and 100 lbs of solvent is preferable (portable tanks generally hold about 10 lbs).
• the source tank 12 also acts as a recovery tank for the recycled, but cleaned solvent.
• the tank 12 has several connections through which the vapor and liquid can move in and out of the tank.
• a liquid take off valve 16 connects to a tube within the tank 12 for receiving liquid solvent from near the bottom of the tank; a valve 18 is connected for receiving recycled solvent; and another connection 20, which is preferably valved at the tank (not shown) can receive vapor from the upper portion of the tank 12.
• the number of valves can be minimized with use of known valves, such as a Y type valve which has both a liquid take off and a vapor take-off.
• the component 14 is connected fluidly to the apparatus 10 so that ' the liquid solvent can be flushed through the component to remove any contamination.
• the solvent in the tank 12 is directed to the component 14 through a fluid conduit 22 which is connectable to the component 14, and the solvent exits the component 14 through another fluid conduit 24 connectable to the apparatus 10.
• the fluid conduits 22 and 24 may include valves as shown to open and close the flow of solvent, and preferably includes flexible hoses 26 or tubing sections for easy handling, and also a see through section, translucent section, or some type of view window so that the flow of solvent can be visually monitored.
• the component 14 is connected preferably to the apparatus 10 to be flushed with the solvent in a flow of solvent opposite the normal flow of refrigerant through the component 14 in normal use.
• the solvent in liquid form, passes from the tank 12 through the component 14 where it picks up the contamination, i.e., oil laden with waxes, dirt, fines and other debris caused by both normal wear and catastrophic failure.
• the solvent exiting the component 14 is then evaporated into a gaseous form, leaving the oil in liquid form for removal from the gaseous solvent. This is accomplished by passing the solvent laden with contaminant (oil) from the component 14 through a restrictor valve 28, where the solvent begins to vaporize, and then an evaporator 30 to complete the vaporization process.
• a bypass valve 36 preferably solenoid operated, allows the expansion valve to be bypassed during the recovery cycle as further described below.
• the evaporator 30 can be a combined three-coil unit where two coils are used as a condenser 32 as further described below, and one coil as the evaporator 30, allowing heat transfer between the evaporator 30 and condenser 32.
• a fan 34 blows air across the evaporator 30 and condenser 32 to enhance the heat exchange. Any suitable arrangement of heat exchangers can be used.
• a strainer 38 on the inlet side of the expansion valve is preferred to remove particulates.
• the cold vapor solvent passes from the evaporator 32 to a helical oil separator 40, which separates any oil droplets and debris (the contamination) from the solvent vapor for collection as further described below.
• a helical oil separator 40 Any suitable type of separator may be used as is known in the art.
• the oil separator has an oil drain valve 42, preferably solenoid operated, for connection to an oil drain bottle 44, the operation of which is described below.
• the vapor passes next through a filter/dryer 46 where any droplets of water remaining particulates are removed. Any suitable desiccant type dryer may be used.
• the filter/dryer may also have the capability of removing acid from the solvent.
• the vapor passes to a compressor 48, which compresses the vapor to a hot vapor.
• a compressor 48 which compresses the vapor to a hot vapor.
• An oil separator 50 located downstream of the compressor, removes any such oil from the hot vapor and returns it to the compressor 34 through an oil return solenoid valve 52 which may be operated cyclically, intermittingly, or on a manner as known.
• This hot vapor from the compressor 48 then passes through a check valve 54 to the fan cooled condenser 32 where it is condensed into hot liquid. .
• the hot liquid is then returned to the source tank 12 through a check valve 56 and the tank valve 18 as clean solvent to be used again in the cleaning cycle. In this way the liquid solvent that is fed to component 14 is recycled and is always clean for reuse.
• the solvent recovery cycle can be carried out.
• a valve on the outlet side of the tank 12 such as the valve 58 (or even tank valve 16) is closed to isolate the solvent source from the component 14, and the compressor 34 is turned on to remove all solvent from the component 14.
• Transparent sections of fluid conduits 22 and 26 allow an operator of the apparatus 10 to visually see when the solvent has stopped flowing, indicating that the solvent was completely removed from the component 14.
• the recovery process can be sped up by bypassing the expansion valve 28 by opening the solenoid valve 36. This makes it easier to evaporate and remove any small amounts of remaining solvent in the component 14. Once all solvent has been recovered, the compressor can be shut off.
• the oil is purged from the apparatus 10 and collected into the oil drain bottle 44.
• a fluid conduit 20 connected to the vapor in the tank 12 is connected through a fluid conduit 60 to the inlet side of the oil separator 40 (downstream of the evaporator 30).
• a solenoid controlled valve 62 controls the flow of vapor from the source tank 12 to the oil separator 40.
• the compressor 48 is turned off and the solenoid controlled valve 62 opened to expose the helical oil separator 40 to the pressure of the source tank 12.
• the pressure from the source tank 12 forces the oil and contaminates previously removed and held in the oil separator 40 into the oil drain bottle 44 for disposal. Draining the oil immediately after the clean cycle is believed to allow collection of a greater fraction of the oil from the component 14. The recovery cycle can then be done. Alternatively, however, the recovery cycle can be completed before the purge cycle if desired.
• a preferred solvent for use with the present invention is
• HFC-245fa HFC-245fa.
• Other suitable solvents may also be used, such as a combination of HFC- 245fa and trans-1 ,2-dichloroethylene.
• suitable solvents such as a combination of HFC- 245fa and trans-1 ,2-dichloroethylene.
• non flammable mixtures or mixtures with no flash point of the two should be used, such as a mixture of 65% HFC-245fa and 35% trans-1 ,2- dichloroethylene by weight, or 50% HFC-245fa and 50% trans-1 ,2-dichloroethylene by weight.
• HFC-365 mfc which when blended with'HFC-245fa may provide a non-flammable mixture, e.g., a blend of 35% HFC-365 mfc and 65% HFC-245fa by weight. It is understood, however, that the present invention is not to be limited to the above mentioned solvents. Other solvents can be used, although such solvents should have certain preferable characteristics or properties.
• solvents for the present application should preferably have no ozone depletion potential.
• a second criteria is that the solvent be non-flammable or have no flash point.
• HFC-245fa is a low boiling solvent as compared to others, e.g., d-limonene, n-bromopropane, and HFE-7100, and is believed to be best suited for this application. Suitable solvents should fall within the boiling range of about 0°C to about 61 °C; a more preferred range is about 5°C to about 55°C; and an even more preferred range is about 10°C to about 45°C. As discussed above, the solvent should be classified as a non-flammable liquid according to DOT regulations.
• the solvent has no flash point and no flammable range.
• One use of the method of the present invention is to clean components of automobile air conditioning systems. It is believed that preferable flow rates of HFC- 245fa as the solvent range between about .1 to about 10 pounds per minute, preferably .1 to 2 pounds per minute for automobile air-conditioning or smaller refrigeration systems cleaning. In one particular trial of the present method, the flow rate of the solvent in cleaning a condenser from an automobile was estimated as being 0.6 to 0.7 pounds of HFC-245fa per minute. For cleaning larger systems such as some rooftop air-conditioning systems, larger flows dependent on the total volume of the systems are required.
• the restrictor valve 28 causes the evaporation of the solvent coming from the component.
• the extent to which this valve is opened is critical to the functioning of the device of the present invention. Under conditions of 25°C and 1 bar, it has been found that if the valve is adjusted to 4 inches of mercury, the oil separation function works very well. However, it would be advantageous to have the valve operated automatically to provide a certain level of superheat, for instance 1 to 15°C superheat at the compressor inlet. Various electronic means of achieving this are known in the industry which can be used for the present invention.
• the use of TXV valves designed for use with the solvents of this invention may also be possible. TXV valves designed for use with various refrigerants are available from Sporlan Valve Company, Parker- Hannifin Corp. and other suppliers. Using standard methods, such suppliers can provide TXV valves for use with the preferred solvents.
• valves shown in Figure 1 are useful with an automated system, hand operated valves may also be used for a manual system. It is also understood that the various components of the apparatus are connected with fluid conduits, such as metal tubing and piping, with suitable valves and connectors as is known in the art.
• the oil was then drained from the oil separator. Eighty (80) grams of oil were recovered. The condenser was weighed before and after and found to have the same weight indicating that all the oil and solvent were removed from it. In yet another trial, 40 grams of mineral oil were added to a condenser from an automobile. Air was then blown into the condenser in such a manner that the oil was spread throughout the condenser. The oil laden condenser was then attached to a flushing machine in accordance with the present invention. The apparatus was then
• the solvent in this was a mixture of HFC-245fa (65 wt. %) and trans-1 ,2 dichloroethylene (35 wt. %), which is a non-flammable mixture.
• the solvent flowed through the condenser. After 10 minutes, the flow of the solvent was stopped and recovery cycle initiated. During this cycle the compressor was run and the solvent remaining in the condenser was returned to the supply tank. The oil was then drained from the oil separator. Forty grams of oil were recovered. The condenser was weighed before and after and found to have the same weight indicating that all the oil and solvent were removed from it.
• the present invention can be used to flush the components of an older automobile air-conditioning system which may have used a hydrocarbon lubricant such as a mineral oil or alkyl benzene oils with a refrigerant such as R-12.
• a hydrocarbon lubricant such as a mineral oil or alkyl benzene oils
• a refrigerant such as R-12.
• a solvent such as HFC-245fa with a solubilizer such as trans-1 ,2 dichloroethylene is suitable for flushing such systems.
• this invention allows for reuse of the solvent through constant redistillation and fast removal of the solvent from the component when the solvent boils close to room temperature.
• a machine can be automated and this operation can be made to operate with one push of a button when nonflammable HFC-245fa is used.
• the apparatus 10 can be a portable unit on wheels, with the solvent tank 12 easily connectable to the portable unit, or a stationary unit.
• the method and apparatus of the present invention removes the contamination from the solvent before recycling the solvent back to the component.
• a further advantage of the present invention is that the time required for removal of the solvent from the component is

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Organic Chemistry (AREA)
• Metallurgy (AREA)
• Materials Engineering (AREA)
• General Chemical & Material Sciences (AREA)
• Life Sciences & Earth Sciences (AREA)
• Oil, Petroleum & Natural Gas (AREA)
• Wood Science & Technology (AREA)
• Cleaning By Liquid Or Steam (AREA)
• Cleaning In General (AREA)
• Vaporization, Distillation, Condensation, Sublimation, And Cold Traps (AREA)

Priority Applications (3)

Applications Claiming Priority (4)

Publications (1)

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Family Applications (1)

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Citations (3)

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• 2004
  • 2004-04-14 US US10/824,094 patent/US20040231702A1/en not_active Abandoned
  • 2004-05-21 JP JP2006533340A patent/JP2007500597A/ja not_active Withdrawn
  • 2004-05-21 CZ CZ20050728A patent/CZ2005728A3/cs unknown
  • 2004-05-21 EP EP04753115A patent/EP1626821A1/en not_active Withdrawn
  • 2004-05-21 CA CA002526622A patent/CA2526622A1/en not_active Abandoned
  • 2004-05-21 WO PCT/US2004/016229 patent/WO2004105971A1/en not_active Ceased
  • 2004-05-24 TW TW093114662A patent/TW200508554A/zh unknown
• 2006
  • 2006-05-24 US US11/420,131 patent/US20060234896A1/en not_active Abandoned

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