Heat exchange – Flow passages for two confined fluids – Interdigitated plural first and plural second fluid passages
Reexamination Certificate
2000-04-14
2002-01-22
Lazarus, Ira S. (Department: 3743)
Heat exchange
Flow passages for two confined fluids
Interdigitated plural first and plural second fluid passages
C165S164000, C165S158000
Reexamination Certificate
active
06340052
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a heat exchanger for making heat exchange between high temperature fluid and low temperature fluid, and especially to a heat exchanger, which permits to provide economical effects and has a high reliability and safety.
2. Description of the Related Art
In general, a heat exchanger is used as a heat/cooling device, an evaporator or a condenser in a plant of electric generation by temperature difference, steam power, chemistry, food engineering and the like, a refrigerator and a heat pump. Such a heat exchanger can make heat exchange between high temperature fluid and low temperature fluid for the purposes of heating, boiling, evaporating, cooling and condensing fluid.
The conventional heat exchanger may be classified into a shell and tube heat exchanger, a plate type heat exchanger, a spiral type heat exchanger and the like. The plate type heat exchanger is generally used as an evaporator for boiling and evaporating a working fluid having a low temperature by heat of a high temperature fluid and as a condenser for absorbing heat through a low temperature fluid to condense a working fluid having a high temperature in a plant of electric generation by temperature difference, a refrigerator and a heat pump. An example of the conventional plate type heat exchanger used as the evaporator and the condenser is shown in
FIGS. 6 and 7
.
FIG. 6
is an exploded perspective view illustrating essential components of the conventional heat exchanger.
FIG. 7
is a schematic descriptive view of the conventional heat exchanger in an assembled condition.
The conventional plate type heat exchanger
100
as shown in
FIGS. 6 and 7
is provided with plural pairs of plates
101
,
102
. In each pair, the plate
101
is placed on the other plate
102
. Upper and lower guide rods
105
,
106
held between a stationary frame
103
and a support rod
104
support the plural pairs of these plates
101
,
102
. The plural pairs of the plates
101
,
102
are firmly held between the stationary frame
103
and a movable frame
107
that is mounted on the guide rods
105
,
106
. Two heat exchange passages A, B are formed on the opposite surfaces of each of the plates
101
,
102
. A heat-exchanger fluid
108
having a high or low temperature flows in the heat exchange passage A and a working fluid
109
flows in the other heat exchange passage B so as to make heat exchange.
The above-mentioned plates
101
,
102
having a prescribed shape and a surface condition can be obtained by press-forming a plate-shaped material. Openings “a”, “b”, “c” and “d” through which the heat-exchanger fluid
108
or the working fluid
109
can pass, are formed at four corners of each of the plates
101
,
102
. Packing members
111
,
112
are placed on the surfaces of the plates
101
,
102
, respectively, so as to prevent the heat-exchanger fluid
108
and the working fluid
109
from flowing in a mixing condition. The plates
101
,
102
have the same shape, but the plates
102
is placed upside down relative to the normal placement of the plate
101
.
However, in the conventional heat exchanger having the above-described structure, the heat exchange fluid
108
or the working fluid
109
supplied between the plates
101
,
102
in the horizontal direction in
FIG. 7
passes through the openings “a”, “b”, “c” and “d” and turns vertically so as to make a vertical flow between the plates
101
,
102
, thus flowing in a complicated manner and leading to a large pressure loss. Accordingly, it is necessary to increase a supplying pressure of each of the fluids. However, the fluid-tightness of the heat exchange passages A, B can not be obtained unless the packing members
111
,
112
are firmly pressed against the plates
101
,
102
. In view of this fact, it is impossible to increase the pressure of the heat-exchanger fluid
108
or the working fluid
109
over the prescribed limit so as to prevent the leakage due to insufficient pressing of the packing members
111
,
112
. A number and size of the plates
101
,
102
are also restricted, thus causing a problem. In addition, when ammonia or a mixture of ammonia and water is used as the working fluid
109
, a sufficient safety cannot be obtained due to the use of the packing members
111
,
112
.
In order to solve the above-mentioned problems, there have conventionally been developed for practical use plate type heat exchangers as the products of ALFA RAVAL Co. Ltd., in which the plates that have been obtained by press-forming the material plate into a prescribed shape were joined with each other by a brazing method without using packing members to form an integral body, while forming heat exchange passages on the opposite surfaces of each plate, and there is no need for movable frame and stationary frame. However, a specific tool is required to join the plates with each other, leading to complicated manufacturing steps and requiring a high manufacturing cost.
When the conventional heat exchanger has a heat transferring face on which irregular portions are formed in order to improve the heat transferring effect and discharge fluid easily, which is produced through condensation, a remarkable pressure loss occurs. When the pressing accuracy for preparation of the plates
101
,
102
is not so high, the plates
101
,
102
come into contact with each other at their portions, which should not come into contact with each other, so that the pressing condition of the plates
101
,
102
changes to impart an adverse influence to the close contact of the packing members
111
,
112
.
The ratio of area of the openings “a”, “b”, “c” and “d” to the plates
101
,
102
is relatively high and these openings are formed by a removing process such as a punching step. Accordingly, a blanking process for the plates
101
,
102
is carried out to form blanks having such waste portions. When the plates are to be used especially for the electric generation by temperature difference in seawater, they are formed of materials such as expensive titanium or special alloy in view of corrosion resistance, thus leading to occurrence of uneconomic problems in material costs. Japanese Patent Provisional Publication No. S60-80082 discloses the other plate type heat exchanger, in which the above-mentioned problems are taken into consideration. The other plate type heat exchanger has a structure in which a number of passage portions that are obtained by forming openings on the plates is limited to two on the upper and lower sides so as to solve the uneconomic problems in material costs and extremely increase the ratio of area of the heat transferring face to the plate. However, the other plate type heat exchanger has the passage portions, resulting in the occurrence of the uneconomic problems in costs of the material as used. In addition, the passage portions of the plate do not contribute to the heat exchange and it is therefore necessary to use the plate, which is larger than the essential area of the heat transferring face.
SUMMARY OF THE INVENTION
An object of the present invention, which was made in order to solve the above-described problems, is therefore to provide a heat exchanger in which the supporting structure of the heat transferring face is improved to permit the non-use of packing members and the release from the restriction due to the use of them, the heat transferring face has a simple shape to reduce the manufacturing cost and reliability and safety are improved.
In order to attain the aforementioned object, the heat exchanger of the present invention for making heat exchange between high temperature fluid and low temperature fluid, said apparatus comprises:
a shell having a box-shape, an inside of which is divided into at least three zones disposed in a prescribed direction by at least two parallel partition walls; and
a plurality of tubular heat transferring members, said heat transferring members comprising a plurality of tubular bodies each having opposite open ends and two surfaces being opposite in pa
Kananen Ronald P.
Lazarus Ira S.
McKinnon Temell
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