High pressure header and heat exchanger and method of making the same

Abstract

A method of providing volume production of highly pressure resistant headers (10), (12) is provided and allows the headers (10), (12) to be formed of a header structure (10), (12) with a relatively thin wall portion (32) and a relatively thick wall portion (30). A strip (40) is utilized to provide the desired thickness at the thin wall portion (32) while allowing both the thin wall portion (32) and the strip (40) to have tube slots (34), (42) formed therein by a one step punching operation.

Description

FIELD OF THE INVENTION [0001] This invention relates to headers for heat exchangers, and more particularly, to headers and heat exchangers incorporating such headers which are designed for extremely high pressure applications. BACKGROUND OF THE INVENTION [0002] Concern for global warming and the deterioration of the ozone layer as a result of the escape of fluorine containing refrigerants from refrigeration systems, including air conditioning systems, has prompted a new look at refrigeration systems utilizing more environmentally friendly refrigerants. One such system under study is a carbon dioxide (CO2) based system wherein CO2 is employed as the refrigerant. CO2 systems operate at significantly higher internal pressure than do conventional systems employing fluorine based refrigerants and as a consequence, there is a need to improve the pressure resistance of heat exchangers used in such applications as, for example, the gas cooler and the evaporator of such systems. [0003] At th...

AI Technical Summary

Benefits of technology

[0007] It is the principal objects of the invention to provide a) a new and improved method for making a header for a high pressure heat exchanger, b) a new and improved header with high pressure resistance for use in high pressure

Problems solved by technology

At the same time, these systems have the potential for extensive use in vehicular air conditioning systems where weight, because of its impact on fuel economy, is of considerable concern.

This consideration makes it impossible to achieve the desired pressure resistance simply by expanding wall thickness of conventional heat exchangers used in such systems without other major changes because of the added weight of thicker walled elements.

Furthermore, this solution is not an economically viable one because taking existing components without changing their size other than to increase wall thickness to achieve pressure resistance means more material will have to go into the heat exchanger, most notably in the headers, thereby increasing the cost of the resulting heat exchanger.

One primary difficulty in this approach is that with smaller diameter headers, the process of forming the tube slots in the headers has become increasingly difficult.

Unfortunately, these machining operations are time consuming and expensive and are particularly more costly than the various punching techniques that have been used to form transverse tube slots in cylindrical headers in conventional heat exchangers utilizing conventional refrigerants.

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