JPH05126478A - Plate type heat exchanger - Google Patents

Abstract

PURPOSE:To improve the heat exchanging efficiency of a plate type heat exchanger by contriving the effective utilization of the heat transfer surface of the heat exchanger. CONSTITUTION:A plate type heat exchanger is made by laminating plates A and plates B alternately while laying respective plates horizontally while the vapor of fluorocarbon, entered from a passage hole 2a on the plates A into the heat transfer surfaces 4a of the same, is condensed and produces liquid drops. The liquid drops are grown to a liquid film while flowing down the heat transfer surfaces 4a, however, the flow down distance of the liquid drops is reduced by laying the plates horizontally whereby the drops arrive at the lower ends of the plates A before the liquid film is grown to a thick film. Accordingly, the heat transfer surface 4a will never be covered by a thick liquid film whereby the vapor is condensed efficiently.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a plate heat exchanger used as a condenser, an evaporator or the like.

[0002]

2. Description of the Related Art A condenser and an evaporator are important elements in a refrigeration cycle system using a refrigerant such as CFC.
As these elements, a small plate type heat exchanger with excellent performance is used. The plate heat exchanger includes a plurality of heat transfer plates (hereinafter, referred to as “heat transfer plates”) having four passage holes and heat transfer surfaces.
It is called a plate. ) Are laminated and the flow paths of the heating medium and the cooling medium are alternately formed between the plates, so that heat exchange between the two media is performed via the heat transfer surface of the plates.
Generally, as shown in FIG. 4, two types of rectangular plates 11 and 14 are vertically placed and alternately stacked. Therefore, for example, the heating medium flows into the heat transfer surface 13 of the plate 11 from the upper left passage hole 12a (inlet side passage hole) side, and then flows out from the lower left passage hole 12b (outlet side passage hole). On the contrary, after the refrigerant flows into the heat transfer surface 13 ′ of the plate 14 from the lower right passage hole 12 c (inlet side passage hole) side,
It flows out from the upper right passage hole 12d (outlet side passage hole). Therefore, the passage hole on the inlet side and the passage hole on the outlet side of each working medium are aligned with one long side of the plate.

[0003]

When the plate type heat exchanger having the above structure is used as, for example, a condenser, as shown in FIG. 5, CFC vapor is introduced into the heat transfer surface 13 from the passage hole 12a on the inlet side. Then, the vapor immediately begins to condense, forming a thick liquid film 15 and covering most of the heat transfer surface 13. As will be described later, the thick liquid film 15 is interposed between the fluorocarbon vapor and the heat transfer surface 13, so that the heat exchange between the vapor and the refrigerant is hindered, and the heat exchange efficiency is reduced accordingly.
In order to prevent this, for example, the plates 11 are placed horizontally and stacked, and as shown in FIG. 6, steam is allowed to flow in from the lower left passage hole 12a side and then to flow out from the lower right passage hole 12b. Alternatively, as shown in FIG. 7, it is conceivable that steam is caused to flow in through the upper left passage hole 12a and then flow out through the upper right passage hole 12b. However, in the structure shown in FIG. 6, uncondensed gas is likely to accumulate on the upper side of the heat transfer surface 13, and the gas reservoir 16 impedes the flow of steam. Further, in the structure shown in FIG. 7, the condensate is not discharged and is accumulated on the lower side of the heat transfer surface 13.
But still hinders the flow of steam. Heat exchange is not performed in the portion where the flow of steam is obstructed, and the effective area of the heat transfer surface is substantially reduced accordingly. Alternatively, FIG.
As shown in FIG. 2, a means using an oblique AC type plate 11 ′ in which the inlet-side passage hole 12a and the outlet-side passage hole 12b are located on a diagonal line and the working medium is made to flow in a diagonal line can be considered. , Heat transfer surface 13 similar to that shown in FIG.
Is covered with a thick liquid film 15. Thus, in the conventional plate heat exchanger, the liquid film 15,
The uncondensed gas pool 16 and the liquid pool 17 hindered the effective use of the heat transfer surface, which was one of the causes for lowering the heat exchange efficiency.

Therefore, an object of the present invention is to improve the heat exchange efficiency of the plate heat exchanger by making effective use of the heat transfer surface.

[0005]

In the present invention, as the heat transfer plate, an oblique alternating current type heat transfer plate having a structure in which a working medium flows diagonally along a heat transfer surface is used, and the heat transfer plate is laterally moved. It was set aside and laminated.

[0006]

The function of the Freon vapor flowing into the heat transfer surface of the plate through the passage hole on the inlet side releases heat and condenses. And
The droplets generated by the condensation flow down the heat transfer surface and flow out from the passage hole on the outlet side. Since vapor flows diagonally through the plate, uncondensed gas pools and liquid pools do not easily form on the heat transfer surface. In addition, since the plate is used horizontally, the vapor can be efficiently condensed. Explaining with reference to FIG. 3, when vapor releases heat of condensation on the heat transfer surface and condenses, droplets are generated, and when the droplets start to flow down and grow, they become a liquid film. When the liquid film cools and is ready to accept the heat of condensation, the vapor condenses on it. In this way, the liquid film gradually thickens as it flows down. However, since it takes a considerable amount of time for the portion where the liquid film is thick to be able to receive the heat of condensation, it is difficult to condense at this portion. That is, the thickened portion of the liquid film on the heat transfer surface contributes little to the heat exchange, and the heat exchange is mainly performed in the thin portion of the liquid film. In other words, it can be said that the thickened portion of the liquid film in the entire area of the heat transfer surface is not effectively used. The reason for laterally placing the plate in the present invention is to reduce this unused portion.
In other words, the liquid film grows as it flows down and its thickness increases, so by placing the plate horizontally to reduce the distance that the liquid film can flow down, the heat transfer surface before the liquid film grows thick Can be drained from. Therefore, as a result of reducing the portion that does not contribute to heat exchange in the entire area of the heat transfer surface, the heat transfer surface is effectively used, and thus the overall heat exchange efficiency is improved.

[0007]

EXAMPLES Examples of the present invention will be described below.

FIG. 1 shows plate A. The plate A is provided with a passage hole 2a on the inlet side and a passage hole 3a on the outlet side on a diagonal line of the plate A having a relatively horizontal rectangle.
A medium such as CFC vapor flowing into the heat transfer surface 4a from the passage hole 2a side flows through the heat transfer surface 4a and is condensed, and then the passage hole 3a.
It is structured to flow out from. Incidentally, 2b and 3b are passage holes for the other medium.

FIG. 2 shows plate B. The plate B is provided with a passage hole 2b on the inlet side and a passage hole 3b on the outlet side on a diagonal line of the plate B having a relatively horizontal rectangle.
The other medium flowing into the heat transfer surface 4b from the passage hole 2b side is
The structure is such that heat is exchanged with the CFC vapor flowing on the heat transfer surface 4a of the plate A, the temperature rises, and then the gas flows out from the passage hole 3b. Incidentally, 2a and 3a are passage holes for Freon vapor.

Plates A and B are alternately laminated to form a heat exchanger. The stacked plates are joined or brazed to ensure external leakage and channels of media.

When the heat exchanger thus constructed is used as a condenser, CFC vapor is caused to flow into the flow path of plate A and another medium is caused to flow into the flow path of plate B. Freon vapor flows into the heat transfer surface 4a through the passage hole 2a. When the chlorofluorocarbon touches the heat transfer surface 4a, it releases the amount of heat and begins to condense, thereby producing a suitable liquid. This liquid suit grows while flowing down on the heat transfer surface 4a and becomes a liquid film, but since the plates A and B are placed horizontally in this heat exchanger to reduce the downflow distance, the liquid film grows. Before reaching the bottom, it reaches the lower end of the plate A and flows out from the passage hole 3a. Therefore, in this heat exchanger, the heat transfer surface 4a is not covered with a thick liquid film, so that it is possible to have a compact structure having excellent heat transfer properties and a small heat transfer area.

On the other hand, the flow path of the plate B becomes a flow path of another medium, but water is generally used as the other medium. Water flows into the heat transfer surface 4b of the plate B through the passage hole 2b. When the water comes into contact with the heat transfer surface 4b, the amount of heat absorbed from the fluorocarbon vapor increases the temperature, and the water flows out from the passage hole 3b.

When this heat exchanger is used as an evaporator, contrary to the above, the medium to be evaporated is made to flow into the heat transfer surface 4a from the passage hole 3a of the plate A and is discharged from the passage hole 2a. Let On the other hand, the other medium is the passage hole 3 of the plate B.
It is made to flow into the heat transfer surface 4b from b and to flow out from the passage hole 2b.

[0014]

As described above, according to the present invention,
Since a diagonal AC heat transfer plate is used and the plates are stacked horizontally, a thick liquid film, uncondensed gas pool, and liquid pool hardly occur on the heat transfer surface, and the heat transfer surface can be effectively used. As a result, the heat exchange efficiency is improved.

[Brief description of drawings]

FIG. 1 is a plan view showing a heat transfer plate A of an oblique AC type.

FIG. 2 is a plan view showing a heat transfer plate B of an oblique AC type.

FIG. 3 is a diagram for explaining a vapor condensation cycle.

FIG. 4 is a perspective view showing a conventional plate heat exchanger.

FIG. 5 is a plan view showing a heat transfer plate of a conventional plate heat exchanger.

FIG. 6 is a plan view showing a heat transfer plate of a conventional plate heat exchanger.

FIG. 7 is a plan view showing a heat transfer plate of a conventional plate heat exchanger.

FIG. 8 is a plan view showing a heat transfer plate of a conventional plate heat exchanger.

[Explanation of symbols]

 A heat transfer plate B heat transfer plate 2a passage hole 3a passage hole 2b passage hole 3b passage hole 4a heat transfer surface 4b heat transfer surface

Claims (1)

[Claims] 1. A plate-type heat exchange in which a plurality of rectangular heat transfer plates having passage holes and heat transfer surfaces are laminated, and flow paths of different working media are alternately formed between adjacent heat transfer plates. Plate-type heat exchanger characterized by using an oblique alternating-current type heat transfer plate having a structure in which the working medium flows diagonally on the heat transfer surface, and stacking the heat transfer plates horizontally ..