US20080245319A1

US20080245319A1 - Heat storage tank

Info

Publication number: US20080245319A1
Application number: US12/080,439
Authority: US
Inventors: Takashi Toyoshima; Yoshio Miyata
Original assignee: Denso Corp
Current assignee: Denso Corp
Priority date: 2007-04-03
Filing date: 2008-04-02
Publication date: 2008-10-09
Also published as: DE102008016639A1; JP2008256241A

Abstract

A heat storage tank 10 comprises a plastic container 11 for storing engine cooling water, an inflow pipe 30 and an outflow pipe 31 communicating with the interior of plastic container 11 and formed to project from plastic container 11, and a heat-insulating layer 13 arranged to cover the whole periphery of plastic container 11 to insulate the heat of the engine cooling water in plastic container 11.

Heat-insulating layer 13 is arranged to cover the roots of pipes 30, 31. Therefore, the heat radiation of the engine cooling water from the bases of pipes 30, 31 can be suppressed thereby preventing a reduction in heat insulation effect.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention
This invention relates to a heat storage tank for storing and insulating a liquid.
2. Description of the Related Art
A cooling system for promoting the warm-up of a water-cooled internal combustion engine of an automotive vehicle has conventionally been proposed in which a heat storage tank for storing and insulating the engine cooling water flowing out of the water-cooled engine is arranged in the cooling water circuit and the high-temperature cooling water stored in the heat storage tank is introduced to the engine to accelerate engine warm-up. This makes it possible to utilize the extraneous heat of the engine effectively and reduce the fuel consumption from the overall viewpoint of the vehicle operation.
Generally, the heat storage tank has a double heat-insulating structure including an inner cylindrical tank of stainless steel making up a heat storage tank body and an outer cylindrical tank of stainless steel, wherein the space between the inner and outer cylindrical tanks is kept substantially in vacuum.

SUMMARY OF THE INVENTION

However, the heat storage tank described above requires two tanks including inner and outer cylindrical tanks which results in increased cost.
In view of the above, the object of this invention is to provide a heat storage tank for reducing cost while at the same time maintaining the insulation effect.
In order to achieve the above object, according to this invention, there is provided a heat storage tank comprising a tank body (11) for storing a fluid, pipes (30, 31) communicating with the interior of the tank body and formed to project from the tank body, and a heat-insulating layer (13) arranged to cover the whole periphery of the tank body including the roots of the pipes and thus to insulate the heat of the fluid in the tank body.
As a result, the use of only a single tank body can reduce the cost without using two tanks, i.e. inner and outer cylindrical tanks.
In addition, since the heat-insulating layer is arranged in such a manner as to cover the whole periphery of the tank body including the bases of the first and second pipes, heat radiation from the bases of the first and second pipes can be suppressed, thereby making it possible to maintain the heat insulation effect.
Incidentally, the reference numerals inserted in the parentheses following the names of the respective means described above represent the correspondence with the specific means, respectively, included in the embodiments described below.
The present invention may be more fully understood from the description of preferred embodiments of the invention, as set forth below, together with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram showing a configuration of a cooling water circuit used for a heat storage tank for automotive vehicles according to this invention.

FIG. 2 shows the external appearance of the vehicle heat storage tank shown in FIG. 2.

FIG. 3 is a sectional view showing the vehicle heat storage tank shown in FIG. 2.

FIG. 4 is a perspective view showing the interior of the vehicle heat storage tank shown in FIG. 2.

FIG. 5 is a diagram showing the flow of the engine cooling water in the vehicle heat storage tank shown in FIG. 2.

FIG. 6 is a diagram showing the assembly steps for the vehicle heat storage tank shown in FIG. 2.

FIG. 7 is a diagram explaining the forming of the film layer shown in FIG. 6.

FIG. 8 is a diagram explaining the forming of the film layer shown in FIG. 6.

FIG. 9 is a diagram explaining the forming of the film layer shown in FIG. 6.

FIG. 10 is a diagram explaining the forming of the film layer shown in FIG. 6.

FIG. 11 is a diagram explaining the forming of the film layer shown in FIG. 6.

FIG. 12 is a diagram explaining the forming of the film layer shown in FIG. 6.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 shows a configuration of the cooling water circuit using the vehicle heat storage tank according to an embodiment of the invention.
The cooling water circuit includes a heat storage tank 10, a four-way valve 20, a heater core 30 and an electrically-operated pump 40. Heat storage tank 10 is for insulating and storing the engine cooling water. Four-way valve 20 connects the outlet side of one of a cylinder head 50 and a cylinder block 51 of the engine to the inlet side of at least one of heater core 30 and heat storage tank 10.
Heater core 30, which makes up a vehicle air conditioning system, is a heat exchanger for heating the air with the engine cooling water. Electrically-operated pump 40 is a circulation pump for supplying the engine cooling water toward the inlet side of each of cylinder head 50 and cylinder block 51.
In the cooling water circuit, a connection is established only between the outlet side of cylinder block 51 and the inlet side of heat storage tank 10 by four-way valve 20 while the temperature of the cooling water is low. As a result, the cooling water stored in heat storage tank 10 can be supplied into cylinder block 51 thereby accelerating the warm-up of cylinder block 51.
In the process, the inlet side of heater core 30 is shut off by four-way valve 20, and therefore the cooling water from heat storage tank 10 flows only to cylinder block 51. Thus, the warm-up of cylinder block 51 can efficiently promoted.
Upon a subsequent temperature increase of the cooling water to a middle level, four-way valve 20 closes the communication between the outlet side of cylinder block 51 and the inlet side of heat storage tank 10, while at the same time connecting the outlet side of cylinder head 50 and the inlet side of heater core 30.
In the process, the engine cooling water (hot water) can be kept in cylinder block 51, and therefore the engine warm-up is accelerated. Further, the engine cooling water heated by cylinder head 50 is circulated between cylinder head 50 and heater core 30, and therefore the air can be heated by heater core 30.
Upon subsequent increase of water temperature to a high level, four-way valve 20 connects the outlet side of cylinder head 50 to the inlet side of heater core 30 and the inlet side of heat storage tank 10. Then, the engine cooling water flows into heat storage tank 10, and therefore the engine cooling water (hot water) for the next warm-up can be stored in heat storage tank 10.
The structure of heat storage tank 10 will be explained. FIG. 2 shows the appearance of heat storage tank 10, and FIG. 3 is a sectional view taken in the plane A in FIG. 2.
Heat storage tank 10, as shown in FIG. 2, is cubic and has an inflow pipe 30 and an outflow pipe 31 projected outward from the lower part of the side wall thereof. Specifically, heat storage tank 10, as shown in FIG. 3, includes a plastic container (tank body) 11 and a heat-insulating member 15 surrounding the whole outer periphery of container 11. Heat-insulating member 15 contains both the exterior of tank body 11 formed as a polyhedron and the base portions of inflow pipe 30 and outflow pipe 31 at the same time. Heat-insulating member 15 includes a plating layer 12 constituting an inner air blocking layer, heat-insulating layer 13 and a film layer 14 constituting an outer air blocking layer.
Plastic container 11 has a cubic structure by combining first and second division casings. Plastic container 11 is connected to inflow pipe 30 and outflow pipe 31 communicating with the interior thereof. Inflow pipe 30 and outflow pipe 31 are formed of a synthetic resin.
Plastic container 11 and pipes 30, 31 are formed of a synthetic resin material, such as PPS, PPA or NY66, mixed with glass fiber. Plastic container 11 and pipes 30, 31 are formed of a member having the thickness of 1 mm to 5 mm.
Plating layer 12 is a thin metal coating (of aluminum, for example) formed by the plating process in such a manner so as to cover the outer surface of plastic container 11. Heat-insulating layer 13 is formed to cover the whole outer surface of plastic container 11 including the bases of inflow pipe 30 and outflow pipe 31. Heat-insulating layer 13 is formed of glass wool, rock wool, urethane foam or polystyrene and the like. Heat-insulating layer 13 has the heat conductivity of not more than 0.01 (kcal/hm ° C.). Film layer 14 is formed of a laminate film and surrounds the whole of heat-insulating layer 13. Film layer 14 and plating layer 12 are formed to prevent the transmission of air.
Plating layer 12 covers the entire outer surface of tank body 11 and the bases of inflow pipe 30 and outflow pipe 31. As a result, the edges of the plating layer 12 is exposed only as two annular edges around the outer periphery of inflow pipe 30 and the outer periphery of outflow pipe 31. On the other hand, film layer 14 is formed in the shape of a cylinder or a bag by folding a tabular film blank and bonding the edges thereof to each other. Film layer 14 has two annular edges around the periphery of inflow pipe 30 and the periphery of outflow pipe 31. Plating layer 12 and film layer 14 are bonded at two points around inflow pipe 30 and the periphery of outflow pipe 31. This configuration is effective for suppressing the heat transfer from plating layer 12 to film layer 14. Joints 21, 23 between plating layer 12 and film layer 14 are referred to as first joints, while joints 20, 22 between film layers 14 are referred to as second joints.
FIGS. 4 and 5 show the internal structure of heat storage tank 10. A plurality of partition plates 40 are arranged in parallel to each other in the vertical direction in heat storage tank 10. Each space between the plurality of partition plates 40 forms a parallel flow path 41. Parallel flow paths 41 are to supply the engine cooling water in vertical direction.
The plurality of partition plates 40 are vertically offset alternately in staggered fashion, and are supported by the bottom surface or the ceiling of heat storage tank 10.
Turn paths 42, 43 for turning the flow of the engine cooling water are formed on the upper or lower side of the plurality of partition plates 40. Turn paths 42, 43 are arranged alternately in the direction in which partition plates 40 are arranged. Turn paths 42 turn the upward flow downward. Turn paths 43 turn the downward flow upward.
The plurality of partition plates 40 are formed of a synthetic resin material integrally with plastic container 11 and pipes 30, 31. The plurality of partition plates 40 are formed of the thickness of 1 mm to 2 mm.
In this configuration, the engine cooling water flows in the plurality of parallel paths 41 and the plurality of turn paths 42 and 43. The engine cooling water thus flows in zigzag as indicated by arrows in FIG. 5. As a result, the engine cooling water flowing in from inflow pipe 30 can flow out from outflow pipe 31 without mixing with the engine cooling water previously existing inside heat storage tank 10.
A method of manufacturing heat storage tank 10 according to this embodiment will be explained.
FIG. 6 is a diagram showing the assembly steps, and FIGS. 7 and 8 are diagrams showing the steps of forming film layer 14.
First, plastic container 11 is formed, as shown in (a) of FIG. 6, by combining first and second division casings 11 a, 11 b.
Next, a thin metal coating is formed, as shown in (b) of FIG. 6, by plating the whole outer surface of plastic container 11. In the process, the thin metal coating is formed in such a manner as to cover the respective roots of pipes 30, 31. Thus, plating layer 12 is formed.
Then, heat-insulating layer 13 is formed on the outside of plating layer 12. Specifically, glass wool (i.e. heat-insulating material) is arranged in such a manner as to cover the whole outer surface of plastic container 11 including the roots of pipes 30, 31 as shown in (c) of FIG. 6.
Next, film layer 14 is formed, as shown in (d) of FIG. 6, on the outside of heat-insulating layer 13.
Specifically, as shown in FIG. 7, a rectangular laminate film 14 a is prepared, and folded back in channel shape as shown in FIG. 8.
Then, as shown in FIG. 9, two end portions 14 b, 14 c of laminate film 14 a are heat sealed to each other. As a result, laminate film 14 a is formed in the shape of a rectangular tube.
Then, as shown in FIG. 10, circular holes 140, 141 are formed in the upper parts of the two opposed side walls of laminate film 14 a in the shape of a rectangular tube.
Then, circular holes 140, 141 are extruded by the heat press process, thereby forming cylindrical portions 140 a, 141 a as shown in FIG. 11.
Next, upper end portions 142, 143 of laminate film 14 a in the shape of a rectangular tube are folded into overlapped form and heat sealed to other. As a result, a heat seal portion 22 (FIG. 3) is formed at the upper end of laminate film 14 a. Heat seal portion 22 represents a part where upper end portions 142, 143 are closely attached to each other by heat sealing.
Laminate film 14 a is formed into the shape of a rectangular tube, and upper end portions 142, 143 thereof are hermetically closed. After that, plastic container 11 with plating layer 12 and heat-insulating layer 13 is inserted into laminate film 14 a in the shape of a rectangular tube as described above.
Then, pipes 30, 31 are inserted into cylindrical portions 140 a, 141 a, respectively. As a result, a first gap is created between cylindrical portion 140 a and pipe 30, and a second gap between cylindrical portion 141 a and pipe 31.
Lower end portions 144, 145 of laminate film 14 a in the shape of a rectangular tube are folded into overlapped form and heat sealed to other ((d) in FIG. 6). As a result, heat seal portion 20 (FIG. 3) is formed at the lower part of laminate film 14 a. Heat seal portion 20 represents a part where lower end portions 144, 145 are heat sealed to other.
Then, vacuum is introduced from the first and second gaps described above. In addition, cylindrical portion 140 a of laminate film 14 a of pipe 30 is heat sealed to plating layer 12. In pipe 31, cylindrical portion 141 a of laminate film 14 a is heat sealed to plating layer 12.
As a result, heat seal portions 21, 23 (FIG. 3) are formed on laminate film 14 a. Heat seal portion 21 represents a part where cylindrical portion 140 a (FIG. 12) of laminate film 14 a is heat sealed to plating layer 12 on the outer surface of pipe 30. Heat seal portion 23 represents a part where cylindrical portion 141 a (FIG. 12) of laminate film 14 a is heat sealed to plating layer 12 on the outer surface of pipe 31. Thus, the space between plating layer 12 and laminate layer 14 a is substantially formed in a vacuum.
According to the embodiments described above, heat storage tank 10 includes plastic container 11 for storing the engine cooling water, inflow pipe (first pipe) 30 and outflow pipe (second pipe) 31 communicating with the interior of plastic container 11 and formed in such a manner as to be projected from plastic container 11, and heat-insulating layer 13 arranged to cover the whole periphery of plastic container 11 and to insulate the engine cooling water in plastic container 11, wherein heat-insulating layer 13 is arranged to cover also the roots of pipes 30, 31.
Thus, the heat of the engine cooling water is prevented from being radiated from the bases of pipes 30, 31. Only one plastic container (tank body) 11 is used, but not two tanks including inner and outer cylindrical tanks, thereby reducing the cost. Therefore, the cost can be reduced while at the same time maintaining the insulation effect.

Other Embodiments

The embodiments described above represent a case in which a thin metal coating is formed as plating layer 12 on the outer surface of plastic container 11. As an alternative for plating layer 12, a thin film made of a synthetic resin material which can shut off the air may be used. The film material may be formed to cover the exterior of plastic container 11 in place of plating layer 12. In this case, the inner film layer replacing plating layer 12 covers the whole tank body 11, and is formed in such a manner as to locate an edge adapted to be bonded with the outer film layer only around pipes 30, 31.
The embodiments described above represent a case in which the space between plating layer 12 and film layer 14 is formed in a vacuum to improve the heat insulation characteristic. Nevertheless, the space may not be formed in a vacuum.
The embodiments described above represent a case in which plastic container 11 is used as a tank body. As an alternative, a metal tank may be used as a tank body.
The embodiments described above represent a case in which inflow pipe 30 and outflow pipe 31 are formed in such a manner as to be projected outward at the lower part of the side wall of plastic container 11. However, the invention is not limited to this configuration, but inflow pipe 30 and outflow pipe 31 may be arranged at any point on plastic container 11. Also, in place of the configuration in which two pipes 30, 31 are extended independently of each other in spaced relation with each other, a configuration may be employed in which pipes 30, 31 are adjacent to each other or provided as a single double pipe.
The embodiments described above represent a case in which the engine cooling water is used as the fluid. As an alternative, other fluids such as the oil may be used.
The embodiments described above represent a case in which heat storage tank 10 is mounted on the vehicle. As an alternative, heat storage tank 10 may be used with any of various devices such as a container for insulating the hot bath water.
While the invention has been described with reference to specific embodiments chosen for purposes of illustration, it should be apparent that numerous modifications could be made thereto by those skilled in the art without departing from the basic concept and scope of the invention.

Claims

1. A heat storage tank comprising:

a tank body for storing a fluid;

pipes communicating with the interior of the tank body and formed to project from the tank body; and

a heat-insulating layer arranged to cover the whole periphery of the tank body including the roots of the pipes and thus to insulate the heat of the fluid in the tank body.

2. The heat storage tank according to claim 1,

wherein the tank body is formed of a synthetic resin material,

wherein an inner air blocking layer is formed on the outer surface of the tank body for preventing the air passage, wherein the heat-insulating layer is arranged on the outside of the inner air blocking layer,

wherein an outer air blocking layer is arranged so as to cover the heat-insulating layer for preventing the air passage, and

wherein the inner and outer air blocking layers are coupled to each other by the edges thereof, and the space between the inner and outer air blocking layers is hermetically closed.

3. The heat storage tank according to claim 2, wherein joints for coupling the inner air blocking layer and the outer air blocking layer to each other are arranged on the outer periphery of the pipes.

4. The heat storage tank according to claim 3, wherein the joints between the inner air blocking layer and the outer air blocking layer are arranged only on the outer periphery of the pipes.

5. The heat storage tank according to claim 1,

wherein the pipes include a first pipe communicating with the interior of the tank body and formed in such a manner as to be projected from the tank body for supplying a fluid into the tank body, and a second pipe communicating with the interior of the tank body and formed in such a manner as to be projected from the tank body for discharging the fluid out of the tank body, and

wherein the tank body comprises a plurality of partition plates arranged therein so that the influent fluid from the first pipe flows out from the second pipe after flowing in zigzag in the tank body.

6. The heat storage tank according to claim 5, wherein the pipes are arranged at the lower part of the tank body.

7. The heat storage tank according to claim 1, wherein the heat-insulating layer has the heat conductivity of not more than 0.01 (kcal/hm ° C.).

8. The heat storage tank according to claim 1, wherein the fluid is the engine cooling water of the automotive vehicle.