HK1117565A - Vapor compression air conditioning or refrigeration system cleaning compositions and methods - Google Patents

Description

Vapor compression air conditioning or refrigeration system cleaning compositions and methods

Cross Reference to Related Applications

This application claims priority to U.S. provisional application 60/538009 filed on 20/1/2004.

Technical Field

The present invention relates to compositions and methods for cleaning lubricated vapor compression systems.

Background

The lubricated vapor compression system and its components need to be cleaned during manufacture and maintenance.

Vapor compression air conditioning and refrigeration systems are well known in the art. They are widely used in applications such as heating, air conditioning and refrigeration. These systems absorb and reject heat as required by the particular application by compressing and expanding a heat transfer agent or refrigerant. Common components of vapor compression systems include: a steam or gas compressor; a liquid pump; heat transfer devices such as gas coolers, intercoolers, aftercoolers, heat exchangers, economizers; vapor compressors such as reciprocating piston compressors, rotary screw compressors, centrifugal compressors, and worm compressors; an evaporator; a liquid cooler and receiver; an expander; control valves and pressure drop restrictions such as capillary and orifice tubes; a refrigerant mixture separation chamber; and a connection pipe and an insulating layer. These components are typically made of aluminum, copper, brass, steel, various plastics, and conventional gasket and O-ring materials.

Most vapor compression systems require the use of a lubricant mixed with the refrigerant due to sliding, rotating, or other moving parts. It is often necessary to clean these systems and their components by removing lubricant and other dirt and debris from their surfaces. Such a requirement is posed, for example, during the retrofit of chlorofluorocarbons (CFCs) to Hydrochlorofluorocarbons (HCFCs) or Hydrofluorocarbons (HFCs), or the retrofit of HCFC refrigerants to HFC refrigerants, as well as during maintenance, particularly after catastrophic events such as compressor burn-out or mechanical failure.

Heretofore, CFCs such as trichloromethane (R-11) and HCFCs such as 1, 1-dichloro-1-fluoroethane (HCFC-141b) have been used as cleaning agents for such systems. Although effective, CFCs and HCFCs are now considered environmentally unacceptable because they are thought to be responsible for the depletion of the stratospheric ozone layer. With the diminishing use of CFCs and HCFCs and the eventual phase-out, there is a need for new cleaning agents that not only work well, but also pose no threat to the ozone layer.

Various environmentally acceptable solvents have been proposed, but their use has met with only limited success. For example, organic solvents such as hexane have good cleaning properties and do not deplete the ozone layer, but they are flammable. Aqueous-based cleaning compositions have no ozone depletion potential and are non-flammable, but tend to be difficult to remove from the surface being cleaned due to their low volatility and the presence of additives therein that leave a residue. In addition, water-based cleaning compositions tend to be inadequate for cleaning typical organic soils found in vapor compression systems. Terpene-based solvents are also difficult to remove from the system, as are water-based cleaning compositions.

Accordingly, there is a need to identify environmentally acceptable cleaning agents that are effective in cleaning vapor compression systems. The present invention satisfies this need.

Summary of The Invention

Disclosed herein are compositions for reducing and removing residue from a vapor compression air conditioning or refrigeration system, said compositions consisting essentially of 1, 1, 1, 2, 2, 3, 4, 5, 5, 5-decafluoropentane and a polyol ester, wherein said polyol ester is selected from the group consisting of neopentyl glycol, glycerol, trimethylolpropane, pentaerythritol and esters of the general formula hoc (o) R¹Esters of carboxylic acids represented by the general formula (I) wherein R¹Is C_6-12Saturated, cyclic, linear or branched hydrocarbon groups.

Also disclosed is a method of reducing residue in a vapor compression air conditioning or refrigeration system, the method comprising: removing substantially all refrigerant and lubricant from the vapor-compression air conditioning or refrigeration system, contacting the vapor-compression air conditioning or refrigeration system with the composition of the present invention for a time sufficient to reduce the amount of residue in the system, and removing the composition from the system.

The invention also includes a method of cleaning a component of a vapor compression system, the method comprising the steps of: rinsing the part with a composition of the invention; and removing the composition from the part.

Detailed Description

Vapor compression air conditioning or refrigeration systems, as used herein, refers to an entire system, a combination of system components, a single component of a system, or portions of a single component of a system. The compositions and methods of the present invention are useful for removing materials including, for example: a steam or gas compressor; a liquid pump; heat transfer devices such as gas coolers, intercoolers, aftercoolers, heat exchangers, economizers; vapor compressors such as reciprocating piston compressors, rotary screw compressors, centrifugal compressors, and worm compressors; an evaporator; a liquid cooler and receiver; an expander; control valves and pressure drop restrictions such as capillary and orifice tubes; a refrigerant mixture separation chamber; and remnants of common compression refrigeration systems that connect components of the tubes and insulation. These components are typically made of aluminum, copper, brass, steel, various plastics, and conventional gasket and O-ring materials.

The residue removed by the compositions and methods of the present invention may include compressor lubricants and particulates, including decomposed lubricants, metals (e.g., aluminum, copper, brass, steel particles from system components), rubber, and plastics (e.g., from system piping and O-rings).

A rinsing or cleaning composition for removing residue from a vapor compression air conditioning or refrigeration system, said composition consisting essentially of 1, 1, 1, 2, 2, 3, 4, 5, 5, 5-decafluoropentane and a polyol ester. The composition may be used as a rinsing composition with a rinsing kit, in a closed loop system, or in any suitable manner to achieve rinsing of a component with the composition of the invention.

1, 1, 1, 2, 2, 3, 4, 5, 5, 5-decafluoropentane (HFC-43-10mee, CF)₃CF₂CHFCHFCF₃) Is a commercial product of e.i. du Pont de Nemours and Company, Wilmington, Delaware, USA.

Polyol esters of the present invention are commercially available from Hatco, New Jersey, USA. The polyol esters of the present invention are the reaction product of a carboxylic acid and at least one polyol selected from the group consisting of neopentyl glycol, glycerol, trimethylolpropane and pentaerythritol. The preferred polyol is neopentyl glycol.

The carboxylic acids used to prepare the polyol esters of the present invention are of the general formula HOC (O) R¹Is represented by, wherein R¹Is C_6-12Saturated, cyclic, linear or branched hydrocarbon groups. Examples of the carboxylic acid include 2, 2-dimethylpentanoic acid, 2-ethylpentanoic acid, 3-ethylpentanoic acid, 2-methylhexanoic acid, 3-methylhexanoic acid, 4-methylhexanoic acid, 5-methylhexanoic acid, cyclohexanecarboxylic acid, cyclopentylacetic acid, 2-ethylhexanoic acid, 3, 5-dimethylhexanoic acid, 2-dimethylhexanoic acid, 2-methylheptanoic acid, 3-methylheptanoic acid, 4-methylheptanoic acid, 2-propylpentanoic acid, 3, 4-dimethylhexanoic acid, cyclohexylacetic acid, 3-cyclopentylpropionic acid, 2-dimethylheptanoic acid, 3, 5, 5-trimethylhexanoic acid, 2-methyloctanoic acid, 2-ethylheptanoic acid, 3-methyloctanoic acid, 2-ethyl-2, 3, 3-trimethylbutanoic acid, 2, 2, 4, 4-tetramethylpentanoic acid and2, 2-diisopropylpropionic acid, 2-methylhexanoic acid, 2-ethylhexanoic acid, 3, 5-dimethylhexanoic acid and 3, 5, 5-trimethylhexanoic acid are preferred. The preferred carboxylic acid is 2-ethylhexanoic acid.

The preferred polyol ester of the present invention is C (CH)₃)₂(CH₂OC(O)R¹)₂Neopentyl glycol ester of wherein each R is¹Independently selected from C_6-12Saturated, cyclic, linear or branched hydrocarbon groups. R¹Preferably saturated, branched C₇Hydrocarbyl, most preferably 1-ethylpentyl. A preferred neopentyl glycol ester is neopentyl glycol di-2-ethylhexanoate (C (CH)₃)₂(CH₂OC(O)CH(C₂H₅)(CH₂)₃CH₃)₂)。

The 1, 1, 1, 2, 2, 3, 4, 5, 5, 5-decafluoropentane and polyol ester composition of the present invention comprises 1, 1, 1, 2, 2, 3, 4, 5, 5, 5-decafluoropentane in an amount of from about 5 to about 25 weight percent, preferably about 15 weight percent, based on the total weight of 1, 1, 1, 2, 2, 3, 4, 5, 5, 5-decafluoropentane and polyol ester, the balance being polyol ester.

Preferred compositions of the present invention consist essentially of about 15 weight percent 1, 1, 1, 2, 2, 3, 4, 5, 5, 5-decafluoropentane and about 85 weight percent neopentyl glycol di-2-ethylhexanoate.

The compositions of the present invention are prepared by adding the weight percentages of each component in a common vessel (optionally with agitation). After mixing, the composition of the invention is obtained.

The present invention also includes a method for reducing or removing residue in a vapor compression refrigeration system comprising: removing substantially all refrigerant and lubricant from the vapor compression refrigeration system, contacting the vapor compression refrigeration system with the above-described 1, 1, 1, 2, 2, 3, 4, 5, 5, 5-decafluoropentane and polyol ester composition for a time sufficient to reduce the amount of residue in the system, and removing the composition from the system.

The present invention also includes a method of cleaning a component of a vapor compression system comprising the steps of: rinsing the part with the above 1, 1, 1, 2, 2, 3, 4, 5, 5, 5-decafluoropentane and polyol ester composition and removing said composition from said part.

In practice, the composition of the present invention may first be applied to a lubricated vapor compression system component surface. Application techniques are well known in the art and include exposing the composition in liquid form to the part or system. The cleaning composition is then removed from the component or system with compressed air or nitrogen.

Suitable cleaning techniques include degreasing specific parts or flushing the system. Degreasing a particular part may be performed in an open or closed degreaser. Such cleaning devices are well known in the art. Various processes for flushing components are known in the art. For example, a part or series of parts may be rinsed by pumping the cleaning composition through the part. After the part is rinsed, the part may be purged with nitrogen or other gas to remove the cleaning composition from the part. Other suitable cleaning methods may also be used to contact the cleaning composition of the present invention with the surface to be cleaned. In practice, the methods of the invention may be carried out as described herein.

A method using a washing method can be used. In this method, the refrigerant and lubricant will be recovered from the air conditioning or refrigeration system and the inlet and outlet of the component to be flushed or cleaned will be disconnected from the system. The method is carried out by injecting a suitable composition such as the composition of the present invention with a rinsing tool. Generally, the flushing means comprises a pressure vessel containing the flushing composition, a nozzle for supplying the composition to the component to be flushed, and a suitable connecting tube, and air or nitrogen or other suitable gas for facilitating the dispensing of the flushing composition from the vessel. Such irrigation tools are commercially available from FJC, inc., moore ville, North Carolina, USA. Alternatively, a closed loop approach may be employed. In this method, the refrigerant and lubricant will be recovered from the air conditioning or refrigeration system and the inlet and outlet of the component to be cleaned or flushed will be disconnected from the system. When a closed loop process is employed, cleaning is accomplished with a suitable closed loop apparatus. Generally, these closed loop devices comprise a reservoir of suitable volume (operated by air, electricity or other suitable means), tubing, filters, etc. fitted with a pump. Such closed loop devices are commercially available from Cliplight co. The pipe connecting the closed-loop device is connected to the inlet/outlet of the component to be cleaned or flushed. The circulation of the rinse composition from the reservoir to the component takes about 30 minutes, or a time sufficient to reduce or remove residue from the component. The part is then purged with dry air or nitrogen for about 30 to about 60 minutes to remove any rinse composition that may remain in the part. The flushing composition can be used several times if the closed loop system is equipped with suitable filters and/or separators etc.

Claims (10)

1. A composition for removing residue from a vapor compression air conditioning or refrigeration system, said composition consisting essentially of 1, 1, 1, 2, 2, 3, 4, 5, 5, 5-decafluoropentane and a polyol ester.

2. The composition of claim 1, wherein the polyol ester is the reaction product of a carboxylic acid and at least one polyol selected from the group consisting of neopentyl glycol, glycerol, trimethylolpropane, and pentaerythritol.

3. The composition of claim 1 wherein said polyol ester is of the formula C (CH)₃)₂(CH₂OC(O)R¹)₂Neopentyl glycol ester of wherein each R is¹Independently selected from C_6-12Saturated, cyclic, linear or branched hydrocarbon groups.

4. The composition of claim 3 wherein each R is¹Is saturated, branched C₇A hydrocarbyl group.

5. The composition of claim 4 wherein each R is¹Is 1-ethylpentyl group.

6. The composition of claim 1 consisting essentially of from about 5 to about 25 weight percent 1, 1, 1, 2, 2, 3, 4, 5, 5, 5-decafluoropentane and from about 75 to about 95 weight percent polyol ester.

7. The composition of claim 1 consisting essentially of about 15 weight percent 1, 1, 1, 2, 2, 3, 4, 5, 5, 5-decafluoropentane and about 85 weight percent polyol ester.

8. A composition for removing residue from a vapor compression air conditioning or refrigeration system, said composition consisting essentially of about 15 weight percent 1, 1, 1, 2, 2, 3, 4, 5, 5, 5-decafluoropentane and about 85 weight percent neopentyl glycol di-2-ethylhexanoate.

9. A method of removing or reducing residue in a vapor compression air conditioning or refrigeration system, the method comprising:

removing substantially all refrigerant and lubricant from the vapor compression system,

contacting the vapor compression system with the composition of any of claims 1 to 8 for a time sufficient to reduce the amount of residue in the system, and

removing the composition from the system.

10. A method of cleaning a component of a vapor compression air conditioning or refrigeration system comprising the steps of:

rinsing the part with a composition according to any one of claims 1 to 8; and

removing the composition from the part.