JPS59173694A - Heat exchanger - Google Patents

Abstract

PURPOSE:To secure an air flow rate at the time of clogging of windward fins by frost to improve the performance by bending both of or either one of the upper and lower ends of fins which are separated for each row of the refrigerant pipe, and by making the bending angle such that it becomes increasingly larger from the leeward side toward the windward side. CONSTITUTION:Fins 2a, 2b, 2c are respectively bent on both ends to make up bent parts 4a, 4b, 4c. Bending angles thetaa, thetab, thetac become increasingly larger within a range of 90 deg. from the leeward of the draft air flow so that they may not overlap in the draft direction. Therefore, the draft air directly hits the bent parts 4a, 4b, 4c and both ends of a fin 2d, and is same for the fins 2a-2b quantatively. Accordingly, as a larger boundary layer leading edge effect is obtained and a nearly even heat exchange can be done with fins 2a-2d, the thermal transmission efficiency can be improved. Even when the windward fin 2a is clogged by frost, drafting is possible through the outside of the top and bottom ends to allow an air flow to the fins 2b-2d, a heat exchanger 1 can maintain the draft air flow rate to maintain the cooling performance.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a fin-tave heat exchanger used in air conditioners, freezers, refrigerators, and the like.

Structure of the conventional example and its problems As shown in Figs. 1 and 2, the conventional fin tube type heat exchanger has a large number of flat plate-shaped fins a and b arranged in parallel, and these fins. In order to improve heat exchange efficiency, each row of refrigerant pipes C is divided into fins A and fins B to reduce the heat transfer coefficient due to the boundary layer leading edge effect. I was trying to improve. However, since fins a and b are all the same shape and size, the leading edge effect of the boundary layer is large because the ventilating air shines directly on fin a in the first row, but from fin b on the second row onwards. 1
Since the fins a in the rows shade the ventilation air, there is a problem in that the ventilation air is not directly affected, and a very large leading edge effect of the boundary layer cannot be obtained. If it is still used as an evaporator and is accompanied by frost, frost will gradually start to form from the first row of fins a, and eventually the frost will spread over the fins 7478 and clog the fins, closing the ventilation passages and increasing the air volume. There were disadvantages in that the cooling performance was also reduced to a large +lJ.

Purpose of the Invention The present invention solves the above-mentioned problems and drawbacks, improves the heat transfer coefficient of the fins of a fin-tube heat exchanger, that is, improves the capacity, and improves the ability of the fin rows on the windward side to avoid frost. The object of the present invention is to provide a device that can ensure ventilation and maintain cooling performance even if clogging occurs.

Structure of the Invention In order to achieve this object, the present invention divides the plate fins into rows with respect to the refrigerant pipes, and bends both or one end of the upper and lower ends of the fins, and this bending angle adjusts the ventilation air flow. By gradually increasing the size from the leeward side to the windward side in the direction,
The improvement in the heat transfer coefficient due to the leading edge effect of the boundary layer, that is, the improvement in capacity, makes it possible to ensure the amount of ventilation and maintain cooling performance even when frost formation progresses.

Description of examples An embodiment of the present invention will be described below with reference to the accompanying drawings.

In FIGS. 3 to 5, reference numeral 1 denotes a fin tube type heat exchanger used as an evaporator for refrigerators, etc., and a large number of plate-shaped fins 2a and 2b are arranged.

2c, 2d, and a refrigerant pipe 3 inserted orthogonally therethrough. Fin 2 a', 2 b,'
2 c has both ends bent and bent piece +a, 4
b.

4C, and the bending angles of the bending pieces 4a, 4b, 4c are θ8. θb, θ. gradually increases within a range of 900 degrees from the lower side of the ventilation airflow (indicated by arrow A), so that the bent pieces 4a, 4b, and 4C do not overlap in the ventilation direction.

In the above configuration, the bending angle θ8. θb, θ. The bending piece 4 is gradually larger than the ventilation side.
A, 4b, 4c and both ends of the fins 2d are directly contacted with ventilation air, and this contact is the same in each row of fins 2a to 2d, so that a larger boundary layer leading edge effect is obtained,
Moreover, substantially uniform heat exchange can be performed in each of the fins 2a to 2d. Furthermore, even when frost is present, the fins 2a
, 2. b, 2c.

2d height or bending angle θ8. θb, θ. are different,
Even if the fins 2a on the windward side become clogged with frost, the upper and lower ends are ventilated on the outside, and the fins 2b, 2c, and 2d (ventilation air flows), and the heat exchanger 1 has a sufficient amount of ventilation.

Therefore, it is possible to improve the heat transfer coefficient due to the leading edge effect of the boundary layer, that is, to improve the capacity, and even if frosting progresses, the amount of ventilation can be ensured and the cooling performance can be maintained.

Effects of the Invention As is clear from the above explanation, the present invention divides the plate fins into rows with respect to the refrigerant pipes, bends both ends or one end of the upper and lower ends of the fins, and adjusts the bending angle. Since the size of each row is gradually increased from the leeward side to the windward side in the direction of the ventilation air flow, each row of fins comes into contact with the ventilation air almost equally, and the heat transfer coefficient due to the boundary layer leading edge effect is reduced. In other words, the ability can be improved, and even if frosting progresses, the amount of ventilation can be ensured and the cooling performance can be maintained.

[Brief explanation of the drawing]

Figure 1 is a perspective view of a conventional fin tube type heat exchanger.
Fig. 2 is a side view of the heat exchanger, Fig. 3 is a perspective view of a heat exchanger according to an embodiment of the present invention, Fig. 4 is a side view of the heat exchanger, and Fig. 5 is a side view of the heat exchanger. It is a front view. 2a, 2b, 2c, 2d...fin, 3...
...refrigerant pipe, 4a, 4b, 4c-.=
-Folded piece, θ8. θb, θ. ...Bending angle.

Claims (1)

[Claims] Consisting of a large number of plate fins arranged and refrigerant pipes passing through the plate fins, the plate fins are divided into rows from the refrigerant pipes, and both or one end of the upper and lower ends of the fins are bent. The bending angle of the heat exchanger gradually increases in each row from the leeward side to the windward side in the direction of ventilation airflow.