Compositions and methods for cleaning vapor compression systems

Inactive Publication Date: 2006-08-17
HONEYWELL INT INC
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Failure to remove these types of contaminants from the system may lead to decreased efficiency or even to the failure of one or more components.
In addition, a vapor compression system may require cleaning after a catastrophic event, such as a compressor blowout.
This type of event can create contaminants, such as acids, sludge, and particulates, within the sealed system.
Failure to remove these types of contaminants from the system may also lead to decreased efficiency or failure of one or more components.
Although effective, CFC's are now considered environmentally unacceptable because of their contribution to the depletion of the stratospheric ozone layer.
Many environmentally acceptable flushing compositions and methods have been proposed, but their use has met with limited success.
However, many of

Method used

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Examples

Experimental program
Comparison scheme
Effect test

example 1

[0025] Eighteen grams of HFC-134a were added to an ebulliometer at atmospheric pressure. It was determined that the compound boiled at about −25° C. HFC-245fa was added to the ebulliometer in increments until there was 7.04 weight percent (wt. %) of HFC-245fa. Surprisingly, the boiling point remained at about −25° C. to about −26° C., indicating that an azeotrope-like composition had formed.

example 2

[0026] A composition comprising 93 wt. % HFC-134a and 7 wt. % HFC-245fa was produced and then transferred into a cylinder having a dip tube. To test the cleaning efficacy of this azeotrope-like composition, a flushing apparatus was assembled that included a cylinder to hold an initial charge of the azeotrope-like composition, a vaporizing expansion device, an oil separator, and a compressor. An article representing a typical vapor compression component, such as a condenser, was weighed and then soiled by depositing approximately 15 grams of polyalkylene glycol (PAG) oil onto its interior surface. The article was then attached to the dip leg of the cylinder containing the azeotrope-like composition so that it could be cleaned.

[0027] The azeotrope-like composition, while in liquid phase, was transferred from the cylinder and through the article. As it passed through the article, it contacted the soiled surface. As a result of this contact, the PAG oil was dissolved by the azeotrope-l...

example 3

[0029] This example illustrates the formation of an azeotrope-like composition according to the present invention and the cleaning efficacy of that composition. For this example, a mixture of 10 wt. % of HFC-134a and 90 wt. % of HFC-245fa was formulated and utilized.

[0030] The procedure specified in Example 1 was followed to prepare the composition, except that a mixture of 10 wt. % of HFC-134a and 90 wt. % of HFC-245fa was formed. Surprisingly, this composition also exhibited azeotrope-like characteristics.

[0031] The cleaning efficacy of this composition was tested using the same procedure specified in Example 1. After this azeotrope-like composition had circulated through the article for 45 minutes, it was found that the substantially all of the PAG oil was removed from the article. The apparatus was turned off and the article was weighted and found to be approximately at its original weight. Thus, none of the azeotrope-like composition or PAG oil remained in the article.

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PUM

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Abstract

Disclosed are azeotrope-like compositions comprising HFC-134a and at least one of HFC-245fa, HFC-365, and HFC-43-10 and methods for using the same to remove contaminants from a vapor compression system.

Description

FIELD OF INVENTION [0001] The present invention relates to non-azeotrope, azeotrope, and azeotrope-like compositions. More specifically, this invention relates non-azeotrope, azeotrope, and azeotrope-like mixtures of hydrofluorocarbons and methods of using the same for removing contaminants from vapor compression systems. BACKGROUND OF THE INVENTION [0002] There exists a need to remove contaminants from vapor compression systems and their ancillary components when these systems are manufactured and serviced. As used herein, the term “contaminants” refers to processing fluids, lubricants, particulates, sludge, and / or other materials that are used in the manufacture of these systems or generated during their use. In general, these contaminants comprise compounds such as alkylbenzenes, mineral oils, esters, polyalkyleneglycols, polyvinylethers and other compounds that are made primarily of carbon, hydrogen and oxygen. [0003] Vapor compression systems are used in a wide variety of appli...

Claims

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Application Information

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IPC IPC(8): F25B47/00F25B43/00
CPCC09K5/04C11D7/505C11D11/0041
Inventor THOMAS, RAYMOND H.PHAM, HANG T.SINGH, RAJIV R.COOK, KANE D.
Owner HONEYWELL INT INC
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