FIN TUBE HEAT EXCHANGER
A fin tube heat exchanger has heat transfer fins disposed in an air flow and plural heat transfer tubes that are inserted in the heat transfer fins and disposed in a direction substantially orthogonal to a flow direction of the air flow. On the heat transfer fins, a set of guide fins and a set of guide fins arranged straightly from upstream to downstream in the flow direction of the air flow are formed, by cutting and raising, on the heat transfer fin surfaces on both sides of the heat transfer tubes. Straight lines that hypothetically interconnect the guide fins and the guide fins slant with respect to the flow direction of the air flow so as to guide the air flow in the vicinities of the heat transfer tubes to rear sides of the heat transfer tubes in the flow direction.
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1. Field of the Invention
The present invention relates to a fin tube heat exchanger, and in particular to a fin tube heat exchanger having heat transfer fins disposed in an air flow and plural heat transfer tubes that are inserted in the heat transfer fins and disposed in a direction substantially orthogonal to a flow direction of the air flow.
2. Background Information
Conventionally, fin tube heat exchangers (i.e., cross fin and tube heat exchangers) having heat transfer fins disposed in an air flow and plural heat transfer tubes that are inserted in the heat transfer fins and disposed in a direction substantially orthogonal to a flow direction of the air flow have been widely used in air conditioners and the like.
In such fin tube heat exchangers, as a heat transfer promoting technique for the purpose of reducing dead water regions formed in the portions of the heat transfer tubes in the heat transfer fins downstream in the flow direction of the air flow and for the purpose of renewing the boundary layers in the heat transfer fins, a technique of forming, by cutting and raising and in positions on the heat transfer fin surfaces on both sides of the heat transfer tubes, guide fins that become larger and open upstream in the flow direction of the air flow has been employed (see Japanese Patent Application Publication (JP-A) No. 61-110889).
SUMMARY OF THE INVENTIONHowever, when a fin tube heat exchanger in which the aforementioned guide fins are employed is used as an evaporator of a heat medium such as refrigerant which uses air as a heat source such as represented by air conditioners and the like, a problem arises in that drain water occurring due to heat exchange between the air and the heat medium accumulates on the guide fins and increases ventilation resistance. Further, when a fin tube heat exchanger in which the aforementioned guide fins are employed is used as an outdoor heat exchanger configuring an outdoor unit of an air conditioner, a problem arises in that, although sometimes frost occurring on the heat transfer fin surfaces is removed by defrosting operation, water drainability is lowered in this case.
It is an object of the present invention to simultaneously achieve a heat transfer promoting effect and water drainability by guide fins in a fin tube heat exchanger.
A fin tube heat exchanger pertaining to a first invention comprises: heat transfer fins disposed in an air flow; and plural heat transfer tubes that are inserted in the heat transfer fins and disposed in a direction substantially orthogonal to a flow direction of the air flow. On the heat transfer fins, plural guide fins arranged straightly from upstream to downstream in the flow direction of the air flow are formed, by cutting and raising, on the heat transfer fin surfaces on both sides of the heat transfer tubes. Straight lines that hypothetically interconnect the plural guide fins slant with respect to the flow direction of the air flow so as to guide the air flow in the vicinities of the heat transfer tubes to rear sides of the heat transfer tubes in the flow direction of the air flow.
In this fin tube heat exchanger, the guide fins are plurally divided from upstream to downstream in the flow direction of the air flow, and the plural guide fins slant with respect to the flow direction of the air flow so as to guide the air flow in the vicinities of the heat transfer tubes to rear sides of the heat transfer tubes in the flow direction of the air flow, so mainly the effect of renewing the boundary layers can be reliably obtained by the guide fins of the plural guide fins that are disposed on the front sides of the heat transfer fins in the flow direction of the air flow and the effect of reducing dead water regions formed of the rear sides of the heat transfer fins in the flow direction of the air flow can be obtained by the guide fins that are disposed on the rear sides of the heat transfer fins in the flow direction of the air flow, and it can be made easier for drain water occurring on the heat transfer fin surfaces to be drained from gaps between the guide fins. Thus, a heat transfer promoting effect by the guide fins can be obtained without being affected by drain water occurring on the heat transfer fin surfaces.
Moreover, because the plural guide fins are straightly arranged from upstream to downstream in the flow direction of the air flow, the guide fins of the plural guide fins that are disposed on the rear sides of the heat transfer fins in the flow direction of the air flow have the same inclination as the guide fins that are disposed on the front sides in the flow direction of the air flow, so not only do they reduce dead water regions formed in portions on the rear sides of the heat transfer tubes in the flow direction of the air flow, but they can prevent new dead water regions from being formed on the backs of the guide fins.
As described above, in the fin tube heat exchanger pertaining to the present invention, the effect of promoting heat transfer by the guide fins can be obtained without being affected by drain water occurring on the heat transfer fin surfaces, and new dead water regions can be prevented from being formed on the backs of the guide fins, so a heat transfer promoting effect and water drainability by the guide fins can be simultaneously achieved.
A fin tube heat exchanger pertaining to a second invention is the fin tube heat exchanger pertaining to the first invention, wherein the height of each of the guide fins gradually increases downstream in the flow direction of the air flow.
In this fin tube heat exchanger, by giving each of the guide fins a shape whose height gradually increases downstream in the flow direction of the air flow, vertical vortexes can be created on the back of each of the guide fins, so that the heat transfer promoting effect by the guide fins can be further raised.
A fin tube heat exchanger pertaining to a third invention is the fin tube heat exchanger pertaining to the first or second invention, wherein a water drainage promoting portion for causing water accumulating between the guide fins that are mutually adjacent on the straight lines to flow downward is formed in the heat transfer fins.
In this fin tube heat exchanger, the water drainage promoting portion is formed between the guide fins, so the ability of the guide fins to drain water can be further raised.
A fin tube heat exchanger pertaining to a fourth invention is the tin tube heat exchanger pertaining to the third invention, wherein the water drainage promoting portion is a slit formed between the guide fins that are mutually adjacent on the straight lines.
A fin tube heat exchanger pertaining to a fifth invention is the fin tube heat exchanger pertaining to the third invention, wherein the water drainage promoting portion is a cutout formed in end portions of the guide fins that are mutually adjacent on the straight lines, which end portions are portions that become lower end portions of the guide fins.
A fin tube heat exchanger pertaining to a sixth invention is the fin tube heat exchanger pertaining to the third invention, wherein the water drainage promoting portion is a water-conducting rib formed between the guide fins that are mutually adjacent on the straight lines.
Below, embodiments of a fin tube heat exchanger pertaining to the present invention will be described on the basis of the drawings.
First EmbodimentIn
The fin tube heat exchanger 1 is a cross fin and tube heat exchanger and is mainly disposed with plural plate-shaped heat transfer fins 2 and plural heat transfer tubes 3. The heat transfer fins 2 are disposed so as to be arranged in a plate thickness direction in a state where the planar direction thereof is generally along a flow direction of an air flow such as that of air. Plural through holes 2a are formed in the heat transfer fins 2 at intervals in a direction substantially orthogonal to the flow direction of the air flow. Portions around the through holes 2a serve as annular collar portions 23 that project towards one side in the plate thickness direction of the heat transfer fins 2. The collar portions 23 contact surfaces of the heat transfer fins 2 adjacent in the plate thickness direction that are opposite of surfaces where the collar portions 23 are formed, such that a predetermined interval H is ensured between each of the heat transfer fins 2 in the plate thickness direction. The heat transfer tubes 3 are tube members inside of which a heat medium such as refrigerant flows; the heat transfer tubes 3 are inserted in the plural heat transfer fins 2, which are disposed so as to be arranged in the plate thickness direction, and disposed in a direction substantially orthogonal to the flow direction of the air flow. Specifically, the heat transfer tubes 3 penetrate the through holes 2a formed in the heat transfer fins 2 and tightly contact the inner surfaces of the collar portions 23 as a result of tube expansion work during assembly of the fin tube heat exchanger 1.
Further, the fin tube heat exchanger 1 of the present embodiment is used in a state where the arranging direction of the plural heat transfer tubes 3 is in a substantially vertical direction. For this reason, the air flow flows so as to cross through the fin tube heat exchanger 1 in a substantially horizontal direction. It will be noted that in the following description, when language such as “upper side” or “upward” and “lower side” or “downward” is used, this will indicate the arranging direction of the heat transfer tubes 3.
(2) Detailed Shape of Heat Transfer FinsNext, the detailed shape of the heat transfer fins 2 used in the fin tube heat exchanger 1 of the present embodiment will be described.
On the heat transfer fins 2, plural (in the present embodiment, two) a set of guide fins 21a and 21b and a set of guide fins 21c and 21d arranged straightly from upstream to downstream in the flow direction of the air flow are formed, by cutting and raising, on the heat transfer fin 2 surfaces on both sides of each of the heat transfer fins 3 (i.e., the lower side and the upper side of each of the heat transfer fins 3). Straight lines L1 and L2 that hypothetically interconnect the guide fins 21a and 21b and the guide fins 21c and 21d slant with respect to the flow direction of the air flow so as to guide the air flow in the vicinities of the heat transfer tubes 3 to rear sides of the heat transfer tubes 3 in the flow direction of the air flow. Here, attack angles α1 and α2 that the straight lines L1 and L2 form with respect to the flow direction of the air flow are set to be within the range of 10° to 30°.
Further, each of the guide fins 21a to 21d is formed such that its height gradually increases downstream in the flow direction of the air flow. In the present embodiment, each of the guide fins 21a to 21d is substantially trapezoidal or substantially triangular (see
In the fin tube heat exchanger 1 configured as described above, the guide fins formed on both sides of each of the heat transfer tubes 3 are divided into the plural (in the present embodiment, two) the set of the guide fins 21a and 21b and the set of the guide fins 21c and 21d from upstream to downstream in the flow direction of the air flow, and the set of the guide fins 21a and 21b and the set of the guide fins 21c and 21d slant with respect to the flow direction of the air flow so as to guide the air flow in the vicinities of the heat transfer tubes 3 to the rear sides of the heat transfer tubes 3 in the flow direction of the air flow, so mainly the effect of renewing the boundary layers can be reliably obtained by the guide fins 21a and 21c of the guide fins 21a to 21d that are disposed on the front sides of the heat transfer fins 2 in the flow direction of the air flow and the effect of reducing dead water regions formed on portions of the rear sides of the heat transfer fins 3 in the flow direction of the air flow can be obtained by the guide fins 21b and 21d that are disposed on the rear sides of the heat transfer fins 2 in the flow direction of the air flow, and it can be made easier for drain water occurring on the heat transfer fin 2 surfaces to be drained from between the guide fins 21a and 21b and between the guide fins 21c and 21d. Thus, a heat transfer promoting effect by the guide fins 21a to 21d can be obtained without being affected by drain water occurring on the heat transfer fin 2 surfaces.
Moreover, because the guide fins 21a and 21b and the guide fins 21c and 21d are straightly arranged on the straight lines L1 and L2 from upstream to downstream in the flow direction of the air flow, the guide fins 21b and 21d of the guide fins 21a to 21d that are disposed on the rear sides of the heat transfer fins 2 in the flow direction of the air flow have the same inclination as the guide fins 21a and 21c that are disposed on the front sides in the flow direction of the air flow, so not only do they reduce dead water regions formed in portions on the rear sides of the heat transfer tubes 3 in the flow direction of the air flow, but they can prevent new dead water regions from being formed on the backs of the guide fins 21b and 21d.
As described above, in the fin tube heat exchanger 1 of the present embodiment, a heat transfer promoting effect by the guide fins 21a to 21d can be obtained without being affected by drain water occurring on the heat transfer fin 2 surfaces, and new dead water regions can be prevented from being formed on the backs of the guide fins 21b and 21d, so a heat transfer promoting effect and water drainability by the guide fins can be simultaneously achieved.
Further, in this fin tube heat exchanger 1, by giving each of the guide fins 21a to 21d a shape whose height gradually increases downstream in the flow direction of the air flow, vertical vortexes can be formed on the back of each of the guide fins 21a to 21d, so the heat transfer promoting effect by each of the guide fins 21a to 21d can be further raised.
(4) ModificationsIn the aforementioned fin tube heat exchanger 1, slits 32 and 35 (see
First, a case where the slits 32 and 35 are formed in the heat transfer fins 2 will be described using
Next, a case where the cutouts 42 and 43 are formed in the heat transfer fins 2 will be described using
Next, a case where the water-conducting rib 52 is formed on the heat transfer fins 2 will be described using
As described above, in the fin tube heat exchanger 1 of the present modification, the ability of the heat transfer fins 2 to drain water can be further raised because the slits 32 and 35, the cutouts 42 and 43, or the water-conducting rib 52 serving as a water drainage promoting portion are formed between the guide fins 21a and 21b that are mutually adjacent on the straight line L1 of the heat transfer fins 2 and between the guide fins 21c and 21d that are mutually adjacent on the straight line L2.
Second EmbodimentIn
Configuration of Fin Tube Heat Exchanger
The basic configuration of the fin tube heat exchanger 101 is the same as the configuration of the fin tube heat exchanger 1 of the first embodiment except for guide fins 121a to 121f of later-described heat transfer fins 102. For this reason, description in regard to the basic configuration of the fin tube heat exchanger 101 will be omitted by changing the reference numerals that relate to the heat transfer fins 102 from the 10s to the 100s.
Next, the detailed shape of the heat transfer fins 102 used in the fin tube heat exchanger 101 of the present embodiment will be described.
On the heat transfer fins 102, plural (in the present embodiment, three) a set of guide fins 121a, 121b and 121c and a set of guide fins 121d, 121e and 121f arranged straightly from upstream to downstream in the flow direction of the air flow are formed, by cutting and raising, on the heat transfer fin 2 surfaces on both sides of each of the heat transfer fins 3 (i.e., the lower side and the upper side of each of the heat transfer fins 3). Straight lines L1 and L2 that hypothetically interconnect the guide fins 121a, 121b and 121c and the guide fins 121d, 121e and 121f slant with respect to the flow direction of the air flow so as to guide the air flow in the vicinities of the heat transfer tubes 3 to the rear sides of the heat transfer tubes 3 in the flow direction of the air flow. Here, attack angles α1 and α2 that the straight lines L1 and L2 form with respect to the flow direction of the air flow are set to be within the range of 10° to 30°.
Further, each of the guide fins 121a to 121f is formed such that its height gradually increases downstream in the flow direction of the air flow. In the present embodiment, each of the guide fins 121a to 121f is substantially trapezoidal or substantially triangular (see
As described above, in the fin tube heat exchanger 101 of the present embodiment configured as described above, whereas the guide fins of the fin tube heat exchanger 1 of the first embodiment had a two-division structure comprising the set of the guide fins 21a and 21b and the set of the guide fins 21c and 21d, the guide fins here have a three-division structure comprising the set of the guide fins 121a, 121b and 121c and the set of the guide fins 121d, 121e and 121f, so the number of gaps between the guide fins for draining drain water occurring on the heat transfer fin 102 surfaces increases. For this reason, the ability to drain water can be raised in comparison to the fin tube heat exchanger 1 of the first embodiment.
(2) ModificationsIn the aforementioned fin tube heat exchanger 101 also, similar to the fin tube heat exchanger 1 of the first embodiment, slits 132, 133, 136 and 137 (see
It will be noted that, because the shapes and the like of the slits, the cutouts and the water-conducting ribs are the same as those of the slits 32 and 35, the cutouts 42 and 43, and the water-conducting ribs 52 pertaining to the modifications of the first embodiment, description thereof will be omitted. Further, in this fin tube heat exchanger 101 also, similar to the fin tube heat exchanger 1 pertaining to the modifications of the first embodiment, slits 131, 134, 135 and 138, cutouts 141 and 146, or water-conducting ribs 151 and 154 may also be formed in portions other than between the guide fins 121a and 121b, between the guide fins 121b and 121c, between the guide fins 121d and 121e, and between the guide fins 121e and 121f.
Other EmbodimentsEmbodiments of the present invention have been described above on the basis of the drawings, but the specific configurations thereof are not limited to these embodiments and are alterable in a range that does not depart from the gist of the invention.
INDUSTRIAL APPLICABILITYBy utilizing the present invention, a heat transfer promoting effect and water drainability by guide tins can be simultaneously achieved in a fin tube heat exchanger.
Claims
1. A fin tube heat exchanger comprising:
- heat transfer fins disposed in an air flow; and
- plural heat transfer tubes inserted in the heat transfer fins and disposed in a direction substantially orthogonal to a flow direction of the air flow,
- wherein
- the heat transfer fins include a plurality of guide fins arranged straight from upstream to downstream in the flow direction of the air flow formed by cutting and raising on the heat transfer fin surfaces on both sides of the heat transfer tubes, and
- straight lines that hypothetically interconnect the guide fins are inclined with respect to the flow direction of the air flow so as to guide the air flow in the vicinities of the heat transfer tubes to rear sides of the heat transfer tubes in the flow direction of the air flow.
2. The fin tube heat exchanger of claim 1, wherein the height of each of the guide fins gradually increases downstream in the flow direction of the air flow.
3. The fin tube heat exchanger of claim 1, wherein the heat transfer fins include a water drainage promoting portion for causing water accumulating between the guide fins to flow downward.
4. The fin tube heat exchanger of claim 3, wherein the water drainage promoting portion is a slit formed between adjacent ones of the guide fins.
5. The fin tube heat exchanger of claim 3, wherein the water drainage promoting portion is a cutout formed in end portions of mutually adjacent ones of the guide fins.
6. The fin tube heat exchanger of claim 3, wherein the water drainage promoting portion is a water-conducting rib formed between adjacent ones of the guide fins.
Type: Application
Filed: Jun 26, 2006
Publication Date: Jul 15, 2010
Applicant: DAIKIN INDUSTRIES, LTD. (OSAKA-SHI OSAKA)
Inventors: Hirokazu Fujino (Osaka), Hyunyoung Kim (Osaka), Toshimitsu Kamada (Osaka), Kazushige Kasai (Osaka)
Application Number: 11/917,994
International Classification: F28F 1/10 (20060101); F28F 13/06 (20060101); F28F 17/00 (20060101);