Heat exchange – Side-by-side tubular structures or tube sections – With manifold type header or header plate
Patent
2000-02-07
2000-12-05
Leo, Leonard
Heat exchange
Side-by-side tubular structures or tube sections
With manifold type header or header plate
165176, 165173, 165153, F28F 904
Patent
active
061553409
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
The invention relates to a heat exchanger comprising a plurality of flat tubes for heat exchange between a first fluid inside said tubes and a second fluid flowing outside of said tubes, a pair of hollow headers connected to the ends of the flat tubes, an inlet and an outlet being provided in the headers for introducing the first fluid into the tubes and discharging it therefrom, each header being composed of at least two parallel tubes with circular cross-sections two adjacent tubes having common wall portions and all tubes of each header constituting a substantially flat array of tubes.
Such a heat exchanger is known from EP-A-0 608 439.
In conventional heat exchangers, such as e.g. disclosed in EP-A-0 359 358, the header consists of a tube with circular cross-section. These tubes have been provided with holes with a shape corresponding to the cross-section of the heat transfer tubes so as to accept the tube ends. This design proves to be very satisfactory with the traditional pressures used in this type of heat exchanger. Commonly at the low pressure side a pressure of 2,5-6 bar has been used, whereas at the high pressure side pressures between 15 and 30 bar are used. With the introduction of higher pressures, the wall thickness of the header has to be increased. This is especially true for heat exchangers using CO.sub.2 at high pressure, where the low pressure is between 35-80 bar and the high pressure between 80 and 170 bar.
This increase in size of the headers has resulted in heat exchangers with large size and weight, which constitutes especially a disadvantage in heat exchanger to be used in mobile equipment such as passenger cars and the like.
The problem with respect to the strength of the header has been overcome by constructing the header as disclosed in EP-A-0 608 439.
In this header a number of parallel tubes has been provided each communicating with a number of heat exchanging tubes. A parallel flow is occurring between the different tubes of the header and the different heat exchanging tubes. A disadvantage of this system is that the pressure drops and therefor the flow patterns in the different available flow paths are all different. This leads to additional losses in pressure and irregularities in the flow which negatively influences the heat exchange.
SUMMARY OF THE INVENTION
It is therefore an object of the invention to provide a heal: exchanger which does not show the disadvantages mentioned above.
This and other objects are achieved in that a number of holes each with a dimension corresponding to the cross-sections of the flat tube is made in the flat surface of each header, and in that the ends of the flat tubes are only inserted in so far into the circular tubes that a communication passage is left between the parallel tubes constituting the header.
BRIEF DESCRIPTION OF THE DRAWINGS
In this way it becomes possible to ensure a cross-flow between the different flat tubes whereby the pressure between the different flow paths is equalised as will as the flow pattern.
FIG. 1 is schematic view of a heat exchanger according to the invention,
FIG. 2 is a cross-section according to the line II--II of the header, shown in FIG. 1,
FIG. 3 is a front view of the header used in the heat exchanger of FIG. 1,
FIG. 4 is a side view of the header of FIG. 3 and
FIG. 5 a front view of the header on enlarged scale according to FIG. 3, showing one hole in more detail.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to FIGS. 1 to 4, the illustrated heat exchanger includes a plurality of flat heat transfer tubes 1 stacked in parallel and corrugated fins 2 sandwiched between the flat tubes 1. The ends 1a of the tubes 1 are connected to headers 3 and 4. Each heat transfer tube may be made of extruded aluminium, having a flat configuration. Alternatively, the flat tubes can be multi-bored flat tubes, commonly called multiport tubes or else, electrically seamed tubes can be used. Multiport tubes may be made by extrusion, but otherwise it is possible to make such tubes by
REFERENCES:
patent: 4386652 (1983-06-01), Dragojevic
patent: 4770240 (1988-09-01), Dawson et al.
patent: 4829780 (1989-05-01), Hughes et al.
patent: 5009262 (1991-04-01), Halstead et al.
patent: 5172761 (1992-12-01), Lyon
patent: 5174373 (1992-12-01), Shinmura
patent: 5307871 (1994-05-01), Jalilevand et al.
Folkedal Leif
Grundlach Peter
Pettersen Jostein
Xu Liming
Hartman Domenica N. S.
Hartman Gary M.
Leo Leonard
Norsk Hydro
LandOfFree
Heat exchanger does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Heat exchanger, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Heat exchanger will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-952339