||||||||||||| USOO5174906A United States Patent (19) 11 Patent Number: 5,174,906 Henry (45) Date of Patent: Dec. 29, 1992

54) FLUSHING OF HEATING, VENTILATING 56) References Cited AND AIR CONDITIONING SYSTEMS USING ENVIRONMENTALLY SAFE MATERIALS U.S. PATENT DOCUMENTS 4,887,435 2/989 Anderson, Jr...... 62/292 4,934.390 6/1990 Sapp ...... 62/303 (75) Inventor: Richard G. Henry, Mayfield Heights, 5,025,633 6/1991 Furmanek ...... 62/292 Ohio 5,036,675 8/991 Anderson, Jr...... 62/292 Primary Examiner-Robert A. Dawson 73 Assignee: Advanced Research Technologies, Assistant Examiner-Ana M. Fortuna Park Ridge, Ill. Attorney, Agent, or Firm-Robert J. Black 57) ABSTRACT A solvent selected from the terpene hydrocarbon group 21 Appl. No.: 766,124 and terpene alcohol group as a cleaning agent can pro vide effective cleaning of heating, ventilating and air lar. conditioning systems which use hydrofluorocarbon or (22 Filed: Sep. 27, 1991 hydrochlorofluorocarbon or Freon refrigerants by using a solvent as described. Flushing through the re

(5) Int. Cl...... CO2F 1/68 frigerant system condenser coils and evaporation coils 52 U.S. C...... 210/765; 210/749; removes any trace of excessive compressor lubricant 210/805; 62/292; 62/303: 134/22. l; which will be carried out with the solvent. The flushed 134/22.19; 252/67 materials carried out are biodegradable, thus are desir 58 Field of Search ...... 210/805, 804, 749, 765; able from an environmental standpoint. 62/303, 292, 77, 85; 252/67, 68; 134/22.1, 22, 19, 108 11 Claims, No Drawings 5,174,906 1. 2 SUMMARY OF THE INVENTION FLUSHING OF HEATING, VENTILATING AND AIR CONDITIONING SYSTEMS USING When it becomes necessary to recharge a compressor ENVIRONMENTALLY SAFE MATERIALS system of a heating, ventilating and/or air conditioning system, it is required that an appropriate flushant sol BACKGROUND OF THE INVENTION vent be used with a circulating pump to remove excess 1. Field of the Invention glycol/ester or petroleum lubricant which may remain The present invention relates to the effective flushing behind as well as any refrigerant. Dipentene and D of heating, ventilating and air conditioning systems and limonene are solvents that are capable of cleaning out 10 any excess lubricant because of their excellent solvent more particularly to cleaning of such systems which ability and their affinity for hydrofluorocarbon and utilize hydrofluorocarbon and hydrochlorofluorocar hydrochlorofluorocarbon and/or Freon refrigerants. bon or Freon refrigerants by the use of solvents selected Normally the circulation of these new solvents from the terpene alcohol and terpene hydrocarbon through the evaporator coils, condenser coils, and re group as a cleaning aid. 15 frigeration compressor systems will clean and degrease 2. Background Art these areas and reduce pollution by using degradable Because of the damage that Freon (CFC) refrigerants materials for the flushing. were doing to the ozone layer, it has become necessary An important feature of the use of Dipentene is its for the development of alternative refrigerants which relatively high flash point of 142 degrees Fahrenheit are more environmentally friendly. Dupont and Inter 20 (open cup). While this is not as good as Freon or hydro national Chemicals are two such companies who devel chlorofluorocarbon solvents which are non-flammable, oped hydrofluorocarbon and hydrochlorofluorocarbon it is sufficiently good so as to allow for safe handling. refrigerants, both of which are much safer to the envi Most other non-halogenated flushants have much lower ronment and have an ozone depletion factor of one flash points such as that of acetone-isopropyl alcohol rather than an ozone depletion factor of 8.0, as is found 25 mixtures which typically have flash points of 15 degrees for Freon refrigerants. Fahrenheit (open cup) which make them unacceptable With the advent of such new refrigerants came new for safe usage for this purpose. Dipentene has an evapo problems associated with their use. One particular prob ration rate of 0.10 (while water is 1). This extremely low lem is that of cleaning of heating, ventilating and air evaporation for Dipentene allows for low inhalation conditioning systems employing these new refrigerants. 30 danger to the user. Dipentene also evaporates leaving When existing systems changed over to the new hydro no residue behind thus leaving the compressor system fluorocarbon and hydrochlorofluorocarbon refriger completely clean and ready for a recharge of appropri ants from the Freon type refrigerants, it was crucial and ate refrigerant. absolutely essential that all of the Freon refrigerant by It has also been determined that cyclohexanone has a complete completely removed before recharging the 35 system with the new refrigerant. Any trace of the old dielectric strength of 42.5 KV, or 42,500 volts, which refrigerant which is left beyond will cause catastrophic makes it a safe solvent to use around electrical equip failure of the compressor system. Thus, it becomes ex ment. Because of this extremely high dielectric value, it tremely necessary to have proper flushing out of these is unlikely that a flashover will occur in most situations. materials. Previously, Freon liquids were used to clean 40 Because of Dipentene's structural characteristics, heating, ventilating and air conditioning systems but namely its cycloaliphatic structure with one double were later determined to have unacceptable side effects bond, it becomes attackable by bacteria found in nature in that such cleaners evaporate quickly but are very and therefore the product is bidodegradable. Unlike destructive to the ozone layer. most aromatic ring structures, such as benzene, which Subsequently, Allied Chemical Company developed 45 are very stable and therefore resistant to biodegrada a flushing solvent called "Genesolve" which is an hy tion. drochlorofluorocarbon liquid that was intended as an Another important property of a flushant is the way ozone safe compressor system flushant. The hydro in which it attacks or for that matter does not attack chlorofluorocarbon liquid is much safer to the ozone gaskets and O-rings found in compressor systems. Di layer but has some serious drawbacks that render it 50 pentene and D-limonene have the ability to dissolve the unacceptable for use as a compressor system flushant. lubricants, moisture and refrigerant but do not dissolve These objections include the extremely powerful sol most gasket materials as demonstrated in the following vent ability of the hydrochlorofluorocarbon liquid. As chart: such, it will attack the gasket materials in any devices used to inject the flushant into the compressor system. 55 SWELL INDEXFORVARIOUS GASKETMATERIALS It also acts as to attack the gasket materials utilized in USING NEW SOLVENTS the refrigerant compressor itself. The hydrochloro D-LEMONENE DIPENTENE fluorocarbon liquid attacks even the most chemically % SWELL %. SWELL resistant gasket materials such as fluoroelastomers, neo NEOPRENE 0.0 0.0. BUTADIENE 0.0 0.2 prene and butadiene. ISOPRENE-NATURAL DISSOLVED DISSOLVED Other solvents, which were experimented with for RUBBER use as a flushant, such as isoppropyl/acetone mixtures BUTACLOR 0.0 0.0 are extremely flammable and non-biodegradable, thus ETHYLENEPROPYLENE- 2.5 .7 making them unacceptable for use as a cleaning aid. DAMINE MONOMER 65 HYCAR 0.0 0.0 Petroleum distillates on the other hand, such as mineral NITRILE 0.0 0.0 spirits, do not evaporate quickly enough and are gener TEFLON 0.0 0.0 ally very flammable and therefore also dangerous to HEXAFLUOROPRO- 0.0 0.0 SC. PYLENE WINYLDIENE 5,174,906 3. 4. -continued quate circulate the solvent through the evaporator SWEL ENDEX FORWARIOUS GASKET MATERALS coils, condensor coils as well as the compressor cham USING NEW SOLVENTS ber of the system to be cleaned. To practice the process, D-LMONENE DIPENTENE place a gallon of mixture as outlined below in the pump SWEL SWE reservoir. This is followed by placing an injector nozzle FLUORDE on the solvent output hose, attaching the injector nozzle at the refrigerant input valve, attach an output hose to Dipentene has a Kauri-butanol value of 67-70 and is the discharge port at the end of the refrigeration circuit a powerful solvent for mineral oil and polyglycols and loop, operate the pump at a flow rate of one gallon per has excellent biodegradability, thus making it usable in O minute, and allow the solvent blend to flow through the this process. The evaporation rate of terpene alcohols refrigeration system, including the evaporator coils and and terpene hydrocarbons can be enhanced by the addi the condensor coils for 1520 minutes while allowing tion of a lower boiling point ketones. Ketones also have the solvent to return to the pump reservoir. As soon as excellent solubility in polyglycol lubricants which fur the solvent has been circulated through the system for ther enhances the cleaning of the lubricant from the 15 the appropriate amount of time, the reservoir is emptied refrigeration system. of solvent. Air is then blown through the system for three to five minutes to evaporate excess solvent from DESCRIPTION OF THE PREFERRED the system. The solvent is disposed of in a landfill where EMBODIMENT it will be degraded by bacteria within 28 days and thus To utilize the solvents described in the foregoing 20 will not be harmful to the environment. Several forms summary, an injection system must be utilized which of the solvent that may be used in the above described can push the solvent through system under pressure. A system are the following examples: simple electric recirculating pump capable of pumping a 1) a solvent containing a 50:50 blend of D-limonene gallon of liquid a minute is utilized to push the solvent and Dipentene. through the evaporator coils and condensor coils as 2) a solvent containing 100% Dipentene. well as the compressor chamber of the heating, ventilat 3) a solvent containing a 50:50 blend of D-limonene ing, air conditioning system. One gallon of Dipentene and terpinolene. or D-limonene should be used to fill the pump reservoir. 4) a solvent containing an 80:20 blend of Dipentene An injector nozzle, which may be fitted into the com and acetone. pressor lubricant reservoir is utilized to push the fluid 30 5) a solvent containing a 50:50 blend of D-limonene through the system and the solvent can be collected at and para-cymene. a discharge port at the end of the refrigeration circuit 6) a solvent blend of 20-90% para-menthadienes (Di loop. After the solvent is pushed through the system, it pentene) and terpene alcohols. is collected and returned to the pump reservoir what is then recirculated through the system until a satisfactory 7) a solvent containing 100% para-cymene. cleaning of all refrigerant and compressor oil and mois While but only selected embodiments of the present ture. It has been found that typically operating the recir invention have been disclosed herein, it will be obvious culating pump for five to ten minutes will remove all the to those skilled in the art that numerous modifications contaminants from the system leaving it clean and ready may be made without departing from the spirit of the for recharging with new refrigerant. The spent solvent 40 present invention which shall be limited only by the may then be discarded and of course because of its scope of the claims appended hereto. biodegradability will be attacked by bacteria and the What is claimed is: environment will not harm the ozone layer. 1. The process of flushing refrigerant from heating, A solvent selected from the terpene hydrocarbon ventilating and air conditioning systems that employ group and terpene alcohol group with best results ob 45 Freon, hydrofluorocarbon or hydrofluorochlorocarbon tained by utilizing Dipentene or D-limonene as a refrig as a refrigerant, comprising the steps of: erant flushant because it contains the following charac preparing a solvent consisting of a mixture of materi teristics for proper cleaning of a heating, ventilating, air als selected from the terpene hydrocarbon group conditioning compressor system which uses Freon re and the terpene alcohol group; frigerant or hydrochlorofluorocarbon or hydrofluoro 50 placing the solvent mixture in the reservoir of a recir carbon as a refrigerant. culating pump; The characteristics of such solvent must be they must connecting an output of said pump to an input of a have good solubility in glycol, ester, and petroleum system to be flushed; based lubricants, as well as good solubility in the above connecting an output of said system to said recirculat described refrigerants. It must also have a 0.2-1% solu 55 ing pump reservoir; bility in water, a flash point above 100 degrees Fahren operating said pump for a predetermined period of heit, it should not attack or dissolve synthetic gasket time; materials, and should also have a dielectric strength of circulating the solvent through said system to cleanse at least 20,000 volts. The product should also have an said system; m evaporation rate of at least 0.10. On evaporation it 60 terminating operation of said pump; should leave no residue to clog the system pumping draining all the solvent and refrigerant and other mechanism. It should also contain no halogens, and be materials contained within said system into said easily degraded by bacteria in the environment. reservoir; To properly utilize the D-limonene or Dipentene as a blowing air through said system to evaporate any of solvent as described, a simple electric recirculating 65 said solvent remaining in said system. pump should be used to provide the necessary pressure 2. The process as claimed in claim 1 wherein: said for the system. The system should be capable of pump solvent contains a 50:50 blend of D-limonene and Di ing approximately one gallon of liquid a minute to ade pentene. 5,174,906 5 6 3. The process as claimed in claim 1 wherein: 8. The process as claimed in claim 7 wherein: said solvent contains 100% Dipentene. said disposal step is followed by disposal of said sol 4. The process as claimed in claim 1 wherein: vent and refrigerant flushed from said system into a said solvent contains a 50:50 blend of D-limonene and land fill to facilitate biodegradability of said dis terpinolene. 5 posed materials. 9. The process as claimed in claim 1 wherein: 5. The process as claimed in claim 1 wherein: Said recirculating pump operates to pump approxi said solvent contains an 80:20 blend of Dipentene and mately one gallon of solvent through said system aCetOne. per minute. 6. The process as claimed in claim 1 wherein: O 10. The process as claimed in claim 1 wherein: said solvent contains a 50:50 blend of D-limonene and said solvent is pumped through said system for a para-cymene. period from 12 to 24 minutes. 7. The process as claimed in claim 1 wherein: 11. The process as claimed in claim 1 wherein: said blowing step is followed by: said blowing of air through said system is for a period emptying said reservoir; 15 of three to five minutes. and disposing of said solvent and said refrigerant. sk sk

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