JPH02106697A - Lamination type heat exchanger - Google Patents

Abstract

PURPOSE:To enable execution of high-efficient heat exchange between a refrigerant and air by a method wherein a slit part extending at right angles with the direction of the flow of air to be cooled is formed in the middle part of the U-shaped recessed part of each heat transfer tube plate with which a flat heat transfer tube is formed. CONSTITUTION:A heat transfer tube plate 4a with which a flat heat tube 4 is formed has structure in which an U-shaped recessed part 9 adapted to form a refrigerant passage is extruded in a state that a joint rib part 11 with which a closed passage is formed in a plate being a raw material is left as it is and an inlet tank part and an outlet tank part 3 for a refrigerant are extruded deeper than the recessed part 9 and a slit part 10 is blanked in the middle part of the U-shaped recessed part 9. Namely, the tube wall extending in the direction of the flow of air of the heat transfer tube 4 is divided by the slit part 10. Thus, since transmission of heat from the air upper stream side to the downstream side through the tube wall is blocked, cooling capacity can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a laminated heat exchanger used in air conditioners and the like, and particularly to a laminated heat exchanger suitable for an evaporator for a car air conditioner.

[Conventional technology]

The conventional stacked heat exchanger used as an evaporator is
As described in Japanese Utility Model Publication No. 56-45035, a flat heat exchanger plate in which a U-shaped refrigerant passage is formed by combining two heat exchanger tube plates each having a U-shaped recess, and a heat exchanger on the air side to be cooled. It has a structure in which many fins are laminated alternately.
A passage partition portion is provided to protrude from the middle portion of the U-shaped recess. At both ends of the U-shaped refrigerant passage, there are provided an inlet and an outlet tank section that communicate with adjacent heat transfer tubes, and a refrigerant inlet vibrator and outlet vibrator are connected to the inlet and outlet tank sections, respectively.

[Problem to be solved by the invention]

In the conventional laminated heat exchanger, the refrigerant that flows in from the inlet vibrator is distributed into the flat heat transfer tubes via the inlet tank located on the downstream side of the air, and first the refrigerant is distributed into the flat heat transfer tubes located on the downstream side of the air with respect to the passage partition. The refrigerant flows through the heat exchanger tube, exchanging heat with the air, then makes a U-turn along the U-shaped refrigerant path, and reaches the air upstream heat exchanger tube.

On the air upstream side, there is a large temperature difference between the evaporation temperature of the refrigerant and the air, so there is a large amount of heat exchange, and the liquid refrigerant completely evaporates, becoming a high-temperature gas refrigerant and flowing from the outlet vibrator through the outlet tank. leak. For this reason.

High-temperature refrigerant gas and low-temperature gas-liquid two-phase refrigerant are placed next to each other across the passage partition of the U-shaped refrigerant passage, and the air upstream refrigerant and downstream refrigerant exchange heat through the heat transfer tubes. There was a problem in that the performance of the heat exchanger deteriorated.

An object of the present invention is to provide a laminated heat exchanger capable of efficiently exchanging heat between a refrigerant and air by preventing heat exchange between a high-temperature refrigerant on the upstream side of the air and a low-temperature refrigerant on the downstream side. Our goal is to provide the following.

[Means to solve the problem]

In order to achieve the above object, the present invention provides a slit section in a direction perpendicular to the flow direction of the air to be cooled, in the middle part of the U-shaped recess in each heat exchanger tube plate that constitutes a flat heat exchanger tube. It is something.

[Effect]

In the present invention, the refrigerant flowing from the inlet tank located on the downstream side of the air flows through the air downstream heat transfer tube of the slit provided in the middle part of the U-shaped refrigerant passage, and the heat of vaporization of the refrigerant causes the refrigerant to flow into the air. It flows along the refrigerant passage while increasing the proportion of gas refrigerant, makes a U-turn, and reaches the air upstream heat exchanger tube.

The air temperature on the upstream side is higher than that on the downstream side, so there is a large temperature difference with the refrigerant, and there is a large amount of heat exchange, so evaporation of the liquid refrigerant is promoted, and as the liquid refrigerant decreases, the temperature of the gas refrigerant increases. However, compared to the evaporation temperature based on the refrigerant pressure,
The temperature of the gas refrigerant increases by 5 to 10°C and reaches the outlet of the heat exchanger tube. Here, the flat heat exchanger tube is thermally divided into the air upstream side and the downstream side by the slit part provided in the middle part of the U-shaped refrigerant passage. It is possible to prevent heat exchange loss due to heat exchange between the high-temperature gas refrigerant on the upstream side of the air and the gas-liquid two-phase low-temperature refrigerant on the downstream side of the air through the tube wall of a heat transfer tube such as an exchanger.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 to 3.

FIG. 1 is a front view of a heat exchanger tube plate constituting a flat heat exchanger tube of a laminated heat exchanger according to the present invention, and FIG.
FIG. 3 is a perspective view showing the overall structure of the laminated heat exchanger according to the present invention.

The heat exchanger tube plate 4a for configuring the flat heat exchanger tube 4 has a U-shaped recess for forming a refrigerant passage, leaving a joining rib portion 11 for forming a sealed passage in the flat plate serving as the material. The refrigerant inlet tank part 2 and the outlet tank part 3 are formed by extruding the refrigerant inlet tank part 2 and the outlet tank part 3 deeper than the recess part 9, and a slit part of 1 degree is punched in the middle part of the U-shaped recess part 9. It has become.

A refrigerant inlet 6a and an outlet 6b are punched out at the bottoms of the refrigerant inlet tank part 2 and outlet tank part 3, respectively. Further, on the opposite side of the refrigerant inlet and outlet tank parts 2 and 3, a folded part 12 bent at a right angle is formed as shown in FIG.

As can be seen from FIG. 3, the heat exchanger tube 4 is made of two heat exchanger tube plates 4a, which are assembled into a flat shape by connecting the refrigerant inlet 6a and the outlet lower a to each other, and joining the joint rib portions 11 to each other. It is structured like this. Further, inside the heat exchanger tube 1, a U-shaped refrigerant passage is formed by combining the U-shaped recesses 9 of the two heat exchanger tube plates 4a. A refrigerant inlet tank portion 2 communicates with the end of the downstream refrigerant passage 9b for the air to be cooled in the refrigerant passage, a refrigerant outlet tank portion 3 communicates with the upstream refrigerant passage 9a, and the refrigerant inlet tank portion 2 A refrigerant inlet 6a and an outlet lower a are open in the outlet tank portion 3, and a refrigerant inlet vibrator 6 and an outlet vibrator 7 are connected to the refrigerant inlet 6a and outlet lower a.

As shown in FIG. 3, the laminated heat exchanger 1 is constructed by alternately stacking a plurality of the flat heat transfer tubes 4 and heat transfer fins 5.

In the laminated heat exchanger 1 of the embodiment, the refrigerant flowing from the inlet vibrator 6 provided at the end of the downstream refrigerant passage 9b for the air to be cooled flows through the inlet 6 provided in the inlet tank portion 2.
a into the heat exchanger tubes 4. Evaporation temperature is approximately 0℃
In the downstream refrigerant passage 9b of the air to be cooled, the air is heated to about 5°C via the heat transfer fins 5 provided on the outside.
It cools down to a certain point and flows down. The liquid refrigerant evaporates due to heat exchange with the air, and reaches the opposite end of the inlet tank part 2 while increasing the proportion of gas refrigerant, where it makes a U-turn and flows into the upstream refrigerant passage 9a of the cooled air. It flows downward from the top of Figure 1.

The inlet temperature of the air flow A shown in Fig. 1 is normally 25°C, and the difference from the refrigerant evaporation temperature is larger than that on the downstream side, so the refrigerant rapidly evaporates and becomes a high-temperature gas refrigerant G. It joins at a and flows out from the exit vibe 7.

In FIG. 1, on the downstream side of the air, the refrigerant in the heat transfer tubes 4 is in a gas-liquid two-phase flow, and has a high heat transfer coefficient.

Since the air temperature is low, the wall temperature of the heat exchanger tube plate 4a is 2 to 3°C, which is close to the refrigerant evaporation temperature. On the other hand, on the air upstream side, the refrigerant in the heat transfer tubes 4 is a gas refrigerant and a single-phase flow, and the heat transfer coefficient is reduced to about 1/10 or less compared to the two-phase refrigerant on the air downstream side. The temperature becomes close to the air temperature, and the wall temperature of the heat exchanger tube plate 4a rises to 10 to 15°C, creating a temperature difference of about 10°C from the downstream side tube wall temperature.

Therefore, in the case of conventional stacked heat exchangers, the temperature gradient in the heat transfer tube sheets caused by this tube wall temperature difference prevents heat transfer from the high temperature gas refrigerant on the upstream side to the lower temperature refrigerant on the downstream side. This causes a problem in that the liquid refrigerant necessary for air cooling is wasted and evaporated, resulting in a reduction in cooling capacity.

On the other hand, in this embodiment of the present invention, in the middle part of the U-shaped recess 9 of each heat exchanger tube plate 4a provided to form a U-shaped refrigerant passage, Since the slit parts 1 to 10 are punched out in the orthogonal direction, the tube wall of the heat transfer tube 4 in the air flow direction is formed by punching out the slit parts 10.
divided by Therefore, heat conduction from the upstream side of the air to the downstream side through the pipe wall is blocked.
Cooling capacity can be improved without causing the problems encountered with conventional stacked heat exchangers.

In addition, in the present invention, the above-mentioned effect is further improved by dividing the heat transfer fins 5 into two parts on the upstream side and the downstream side with the slit portion 10 as a boundary.

〔Effect of the invention〕

According to the present invention described above, a slit portion is provided in the middle portion of the U-shaped recess in each heat exchanger tube plate constituting the flat heat exchanger tube in a direction perpendicular to the flow direction of the air to be cooled. In addition, since the tube wall of the heat transfer tube in the air flow direction is thermally divided into the air upstream side and the downstream side by the slit section, the air upstream side high temperature gas refrigerant and the air flow through the tube wall of the heat transfer tube. , it is possible to prevent heat exchange loss due to heat exchange with the gas-liquid two-phase low-temperature refrigerant on the downstream side of the air, and therefore, it has the effect of efficiently performing the heat exchange action between the refrigerant and the air, which in turn improves the cooling capacity. There are benefits to be gained.

[Brief explanation of drawings]

Figure 1 shows '!' according to the present invention. ! Figure 2 is a front view of the heat exchanger tube plate that constitutes the flat heat exchanger tubes of the layered heat exchanger.
FIG. 3 is a side cross-sectional side view taken along the line ■-■ in the figure. FIG. 3 is a perspective view showing the overall structure of the laminated heat exchanger according to the present invention. 1... Laminated heat exchanger, 4a - Heat exchanger tube plate, 4... Flat heat exchanger tube, 5... Heat transfer fin, 9... U-shaped depression, 9a... Air to be cooled Upstream refrigerant passage, 9b
... Similarly, downstream refrigerant passage, 1-0... Slit portion, A... Air flow, G... Gas refrigerant, L... Liquid refrigerant. Agent Patent Attorney Katsuma Ogawa 1. −′) r times 1=−,,. Tomizu Diagram

Claims (1)

[Claims] 1. a U-shaped recess for forming a refrigerant passage;
Two heat exchanger tube plates having a refrigerant inlet and an outlet provided at both ends of the U-shaped recess are connected to each other so that the refrigerant inlet and outlet are communicated with each other, and the surface side having the U-shaped recess is are joined and combined to form a flat heat transfer tube with a U-shaped refrigerant passage inside, and a laminated heat exchanger is constructed by alternately stacking a plurality of these flat heat transfer tubes and heat transfer fins. 1. A laminated heat exchanger, characterized in that a slit portion is provided in the middle portion of the U-shaped depression in each of the heat exchanger tube plates in a direction perpendicular to the flow direction of the air to be cooled.