Stack type evaporator

Details Stack type evaporator Stack type evaporator

1999-11-09

2001-05-15

Leo, Leonard (Department: 3743)

Heat exchange

With vehicle feature

C165S144000, C165S153000, C165S176000

Reexamination Certificate

active

06230787

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates in general to heat exchangers for use in automotive air conditioners, and more particularly to evaporators of a stack type.
2. Description of the Prior Art
In order to clarify the tasks of the present invention, two conventional stack type evaporators
1
and
1
′ for automotive air conditioners will be described with reference to
FIGS. 24
to
26
and
FIGS. 27
to
30
.
One of them is shown in
FIGS. 24
to
26
, which is described in for example Japanese Patent First Provisional Publication 62-798 and Japanese Patent 2,737,286.
As is seen from
FIGS. 24 and 25
, the first conventional evaporator
1
comprises a core unit
5
. Refrigerant inlet and outlet pipes
3
and
4
are fluidly connected to the core unit
5
, which are held by a coupler
2
. Under operation, a liquid-gaseous refrigerant is led into the core unit
5
through the inlet pipe
3
and evaporates to cool the core unit
5
. With this, air flowing through the core unit
5
is cooled. Gaseous refrigerant produced as a result of the evaporation is led into the outlet pipe
4
and into a compressor (not shown). The evaporator
1
is of a so-called “stack type” which comprises a plurality of elongate flat tubes or heat exchanging elements which are stacked, each including two mutually coupled elongate shell plates. Japanese Patent 2737286 shows an alternate arrangement of two areas for the refrigerant, one being a lower temperature area mainly occupied by a liquid refrigerant and the other being a higher temperature area mainly occupied by a gaseous refrigerant. With this alternate arrangement, the evaporator can exhibit a desired temperature distribution thereon.
As is seen from
FIG. 25
, in assembly of the air conditioner, the evaporator
1
and a heater core
9
are arranged perpendicular to a dash panel
8
by which an engine room
6
and a passenger room
7
are partitioned, and air for conditioning the passenger room is forced to flow in the direction of the arrow “a”, that is, in a direction parallel with the dash panel
8
. Although not shown in the drawing, a duct is provided in the passenger room
7
to assure such air flow. That is, the evaporator
1
and the heater core
9
are installed in the duct. The coupler
2
is exposed to the engine room
6
through an opening
10
formed in the dash panel
8
, so that the evaporator
1
is fluidly connected through pipes to a compressor (not shown) and a condenser (not shown) which are arranged in the engine room
6
.
Nowadays, for improving air flow in the passenger room
7
, there has been proposed an arrangement wherein, as is seen from
FIG. 26
, the evaporator
1
and the heater core
9
are arranged in parallel with the dash panel
8
, and the air for conditioning the room
7
is forced to flow in the direction of the arrow “b”. However, in this case, it becomes necessary to use much longer and complicated pipes as the inlet and outlet pipes
3
and
4
as is easily understood from the drawing. Of course, such arrangement brings about increase in cost of the air conditioner. Furthermore, due to usage of such complicated and longer pipes
3
and
4
, the flow resistance of the refrigerant becomes marked and thus the air conditioner fails to exhibit a satisfied performance.
The other conventional stack type evaporator
1
′ is shown in
FIGS. 27
to
30
, which is described in for example Japanese Patent First Provisional Publication 62-798 and Japanese Utility Model First Provisional Publication 7-12778.
As is seen from the drawings, the second conventional evaporator
1
′ comprises a core unit
3
′. The core unit
3
′ comprises a plurality of elongate flat tubes
10
′ (or heat exchanging elements) which are stacked, each including two mutually coupled elongate shell plates. Each elongate flat tube
10
′ has two mutually independent flow passages
2
′ and
2
′ defined therein. A plurality of heat radiation fins
11
′ are alternatively disposed in the stacked elongate flat tubes
10
′. The two passages
2
′ and
2
′ defined in each flat tube
10
′ have upper and lower tank spaces. By connecting or communicating adjacent flat tubes
10
′ at the respective upper and lower tank spaces, there are formed a plurality of tank portions
4
′,
5
′ and
6
′. As is seen from
FIGS. 28
to
30
, at one end of the core unit
3
′, there is provided a side tank portion
7
′ by which the two tank portions
4
′ and
4
′ are connected. Under operation, a liquid-gaseous refrigerant is led through an inlet pipe
8
′ and the inlet tank portion
5
′ (see
FIG. 28
) into the core unit
3
′. The refrigerant flows in the passages
2
′ and
2
′ of the core unit
3
′ while evaporating to cool the core unit
3
′. During this, the refrigerant flows also in the side tank portion
7
′. Thus, air flowing through the core unit
3
′ in the direction of the arrow “&agr;” (see
FIGS. 28
to
30
) is cooled. Gaseous refrigerant produced as a result of the evaporation is led to an outlet pipe
9
′ and to a compressor (not shown).
However, the above-mentioned other conventional stack type evaporator
1
′ has the following drawbacks due to its inherent construction.
First, actually, the side tank portion
7
′ does not contribute anything to the air cooling because the portion
7
′ is positioned away from the air passing path. This brings about unsatisfied performance of the air conditioner.
Second, as is seen from
FIG. 29
, under operation of the evaporator
1
′, due to the nature of the gravity, the liquid-gaseous refrigerant flowing in the upper tank portions
5
′ and
4
′ of the core unit
3
′ is forced to feed a larger amount of refrigerant to upstream positioned flow passages
2
′ and
2
′ and a smaller amount of refrigerant to downstream positioned flow passages
2
′ and
2
′. The amount of the refrigerant in each area of the flow passages
2
′ and
2
′ is indicated by the down-pointed arrows in the drawing. While, due to inertia of the refrigerant, the refrigerant flowing in the lower tank portions
4
′ and
4
′ of the core unit
3
′ is forced to feed a smaller amount of refrigerant to upstream positioned flow passages
2
′ and
2
′ and a larger amount of refrigerant to downstream positioned flow passages
2
′ and
2
′. The amount of the refrigerant in each area of the flow passages
2
′ and
2
′ is indicated by the up-pointed arrows in the drawing. That is, the refrigerant flow rate in the core unit
3
′ is smaller in the inside portion than the outside portion. Thus, as is seen from
FIG. 31
, the core unit
3
′ fails to have a uniformed temperature distribution therethroughout. That is, in the drawing, the outside portions of the core unit
3
′ indicated by grids are forced to show a low temperature as compared with the inside portions thereof. This means that the air passing through the core unit
3
′ fails to have a uniformed temperature distribution, which tends to make passengers in the passenger room uncomfortable.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide a stack type evaporator which is free of the above-mentioned drawbacks.
According to a first aspect of the present invention, there is provided a stack type evaporator which comprises a first mass including first heat exchanging elements, each first heat exchanging element having mutually independent first and second passages; a second mass including second heat exchanging elements, each second heat exchanging element having a generally U-shaped third passage which has first and second ends, the second mass being arranged just beside the first mass in such a manner that the first and second heat exchanging elements are aligned on a common axis; an inlet tan

Affiliated with

Also associated with

Rating

Stack type evaporator does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Stack type evaporator, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Stack type evaporator will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2445843