The present invention relates to a fin-tube type heat exchanger, and more particularly, to a heat exchanger applied to a refrigerator for producing cold air to be supplied to a refrigerating chamber and a freezing chamber.
In addition to the refrigerating chamber and the freezing chamber separated from each other, the refrigerator is provided with a so called machine room in a lower part thereof, and air passages in a rear part of the refrigerating chamber and the freezing chamber connected thereto. The heat exchanger (evaporator) is fitted on the air passages, together with a fan, for supplying cold air to the refrigerating chamber and the freezing chamber in association with a compressor and condensers in the machine room. That is, high temperature and high pressure refrigerant supplied through the compressor and the condensers is evaporated in the heat exchanger, to cool down environmental air by a latent heat of the vaporization. The fan circulates air throughout the refrigerator for supplying the air cooled down through the heat exchanger to the refrigerating chamber and the freezing chamber, continuously.
A related art heat exchanger for the refrigerator is illustrated in FIGS. 1 and 2, referring to which the related art heat exchanger will be explained.
As shown, the heat exchanger is provided with refrigerating tube 1 for flow of the refrigerant, and a plurality of fins 1 fitted at fixed intervals parallel to one another along the refrigerating tube 1.
In more detail, the refrigerating tube 1 is coupled with the fins 2 while one line of the refrigerating tube 1 forms one column in the heat exchanger. FIG. 2 illustrates two columns formed by two lines of refrigerating tube 1.
As shown in FIG. 2, the fin 2, actually in a form of small plate, has through holes 2a for coupling with the refrigerating tube 1. That is, the related art heat exchanger has discrete fins 2, to form discrete heat exchange surfaces along a length of the heat exchanger.
Moreover, during operation, much moisture in the air in the refrigerator is frosted on surfaces of the heat exchanger owing to a subzero environmental temperature, to impede circulation of the air. Therefore, in general, there is defroster 3 provided to the heat exchanger for defrosting, for which separate defrosting process is conducted.
The heat exchanger is fitted to stand upright in the air flow passage, and the air in the refrigerator is introduced into the heat exchanger from below and exits from a top of the heat exchanger as shown in arrows.
Currently, despite the foregoing heat exchangers are applied to most of the refrigerators, the heat exchangers have the following structural problems, actually.
For an example, the fins 2 are fitted to the refrigerating tube 1 one by one because the fins 2 are discrete and have individual shape characteristics. The fins 2 are fitted along the refrigerating tube at intervals different from each other between an upper part and a lower part thereof. That is, as a flow resistance caused by the growth of the frost deteriorates a heat exchanger performance, the fins 2 are fitted in the lower part, an air inlet side, that has more frosting at intervals larger than the upper part.
Water from the defrosting stays at lower edges 2b of the fins 2 in a form of a relatively big water drop by surface tension, and acts as nuclei of frost growth in a subsequent operation of the refrigerator (cooling process), again. Therefore, in order to suppress the growth of the frost, as shown, it is required that the defroster is arranged so as to be in contact with every lower edge 2a. 
At the end, the use of the discrete type of fins makes a structure of the related art heat exchanger complicate actually, that makes assembly difficult. Moreover, it is preferable that the heat exchanger is small sized and has a high efficiency because the heat exchanger is placed in the comparatively small air flow passage. However, the foregoing structural problem impedes design change of the related art heat exchanger, for optimization of the heat exchanger.
The object of the present invention, devised for solving the foregoing problems, lies on providing a heat exchanger for a refrigerator, which has a simple structure, and is easy to fabricate.
Another object of the present invention is to provide a heat exchanger for a refrigerator having an improved heat exchange performance.
To achieve the objects of the present invention, there is provided a heat exchanger for a refrigerator including refrigerating tubes for flow of refrigerant, and a plurality of straight fins having lengths different from one another for coupling with the refrigerating tubes in parallel to each other at fixed intervals through pass through holes formed therein, to form sections with fin spaces different from one another, wherein a section with the smallest fin spaces is below 75% of an entire size.
The section with the smallest fin space is more than 5% of the entire size, and the smallest fin space is 1 mm-13 mm.
Preferably, the section with the smallest fin space is 5%-65% of the entire size, and the smallest fin space is 2 mm-12 mm. It is more preferable that the section with the smallest fin space is more than 15%-55% of the entire size, and the smallest fin space is 4 mm-10 mm.
In the set up section ratios, the fin space increases by 2xc2x72(nxe2x88x921) times of the smallest fin space, where nxe2x89xa71.
The generalized fin spaces are formed by an arrangement pattern having the longest one pair of fins. Fins with intermediate lengths arranged between the one pair of the longest fins, and the shortest fins arranged in every space between the one pair of the longest fins and the fins with intermediate lengths, wherein the spaces between adjacent fins have a ratio of 1:2:4.
The fin space increases by 3xc2x72(nxe2x88x921) times of the fin space of the section with the smallest fin spaces, and the section with the smallest fin spaces is 15%-75% of the entire size, where nxe2x89xa71, and the smallest fin space is 3 mm-13 mm.
Preferably, the section with the smallest fin space is 25%-65% of the entire size, and the smallest fin space is 5 mm-12 mm.
The fin spaces are formed by an arrangement pattern having the longest one pair of fins, fins with intermediate lengths arranged between the one pair of the longest fins, and the shortest two fins arranged in every space between the one pair of the longest fins and the fins with intermediate lengths, wherein the spaces between adjacent fins have a ratio of 1:3:6.
The fin space increases by 4xc2x72(nxe2x88x921) times of the fin space of the section with the smallest fin spaces, and the section with the smallest fin spaces is 25%-75% of the entire size, where nxe2x89xa71, and the smallest fin space is 5 mm-15 mm.
Preferably, the section with the smallest fin spaces is 35%-75% of the entire size, and the smallest fin space is 6 mm-13 mm.
The fin spaces are formed by an arrangement pattern having the longest one pair of fins, fins with intermediate lengths arranged between the one pair of the longest fins, and the shortest two fins arranged in every space between the one pair of the longest fins and the fins with intermediate lengths, wherein the spaces between adjacent fins have a ratio of 1:4:8.
When the section with the smallest fin spices is 5%-75%, 5%-65%, and 15%,-55% of the entire size, the section with the largest fin space is 18% of the entire size, and the smallest fin space is 5.5 mm-10 mm, and more preferably, 6.1 mm-9.1 mm.
When the section with the smallest fin spaces is 5%-75%, the section with the largest fin space may be 18%-25% of the entire size, and the smallest fin space is 6.0 mm-8.5 mm, and more preferably, 6.2 mm-7.7 mm.
When the section with the smallest fin spaces is 5%-65%, and 15%-55%, the section with the largest fin space may be 18%-35% of the entire size, and the smallest fin space is 6.1 mm-8.2 mm, and more preferably, 6.5 mm-7.7 mm.
Preferably, the fin has a top edge and a bottom edge, both are sloped at an angle, and, more preferably, the top and bottom edges are sloped in the same directions.
In more detail, the bottom edge may include a single slope or a plurality of slopes. The slope may have one bottom, or one peak, or a plurality of peaks and bottoms.
More preferably, the fins are arranged such that no tips of the bottom edges with the slope or slopes face each other. The bottom edges with single slopes may be arranged to cross each other, alternately. Or, the bottom edge with a single peak and the bottom edge with a single bottom may be arranged; alternately.
Preferably, the slope angle of the bottom edge may be within 20xc2x0-30xc2x0, and more preferably within 23xc2x0.
More preferably, the fin includes a plurality of slits and louvers formed along a length direction thereof. The slits and louvers are on either face of the fin, or both faces of the fin, alternately. In the foregoing cases, it is preferable that slits and louvers on adjacent fins are arranged, alternately.
In the meantime, preferably, the heat exchanger of the present invention further includes one pair of reinforcing plates coupled to opposite ends of straight parts of refrigerating tube in parallel to the arranged fins. The reinforcing plate includes at least one slit for communication with the slits in the fins, and the bottom edge sloped at an angle.
The heat exchanger of the present invention further includes a defroster fitted to the heat exchanger spaced a fixed distance from the bottom edges of the fins for removal of frost on the refrigerating tube and the fins. The defroster is arranged to keep in contact with middle parts of the fins and the reinforcing plates. To do this, the fins and the reinforcing plates include notches for receiving the defroster.
The present invention actually simplifies a structure and assembly of the heat exchanger, and improves a heat exchange performance. Accordingly, the heat exchanger of the present invention is optimized to suit to a refrigerator.