CROSS REFERENCE TO RELATED APPLICATION

This application is a U.S. national stage application of International Application No. PCT/JP2018/022575, filed on Jun. 13, 2018, the contents of which are incorporated herein by reference.

TECHNICAL FIELD

The present disclosure relates to a heat exchanger, a heat exchanger unit provided with the heat exchanger, and a refrigeration cycle apparatus, and particularly to a structure of a spacer that maintains an interval between fins installed on heat transfer tubes.

BACKGROUND

Some heat exchanger has been known that is provided with flat tubes, to improve heat exchange performance, that are each a heat transfer tube having a flat sectional shape with multiple holes. One example of such a heat exchanger is a heat exchanger where flat tubes are arranged at predetermined intervals from one another in the up-and-down direction with the direction of pipe axes extending in the lateral direction. In such a heat exchanger, plate-like fins are aligned in the direction of the pipe axes of the flat tubes, and heat is exchanged between air passing through between the fins and fluid flowing through the flat tubes. Some fin has been known that is provided with a fin collar at the rim of an insertion portion for the flat tube. The fin collar ensures a separation between the fins by causing the distal end of the fin collar to be in contact with the next fin. By maintaining an appropriate interval between the fins disposed next to each other, resistance against frost and drainage properties of the heat exchanger are ensured to prevent the reduction of heat exchange performance of the heat exchanger.

In Patent Literature 1, by raising opposite end portions, in the longitudinal direction, of the rim of an insertion portion, into which the flat tube is inserted, from the plate surface of the fin, the opposite end portions are in contact with the next fin. In Patent Literature 2, by raising a portion of the plate surface of the fin, which is a portion other than the rim of an insertion portion, the portion is caused to be in contact with the next fin. In Patent Literature 3, by raising a portion of the rim of an insertion portion for the flat tube, which is a portion that faces the long side of the section of the flat tube, the portion is caused to be in contact with the next fin.

PATENT LITERATURE

Patent Literature 1: Japanese Unexamined Patent Application Publication No. 10-78295

Patent Literature 2: Japanese Patent No. 5177307

Patent Literature 3: Japanese Unexamined Patent Application Publication No. 2017-198440

In Patent Literature 1, by raising the opposite end portions, in the longitudinal direction, of the rim of the insertion portion, a spacer is obtained that maintains the interval between the arranged fins and hence, a standing portion formed at a portion of the rim of the insertion portion that extends along the longitudinal direction is short. The standing portion is joined to the flat tube and transfers heat to the flat tube. A problem, however, is caused in that heat exchange performance is reduced as the standing portion is short.

In Patent Literature 2, another spacer that maintains the interval between the arranged fins is provided to a portion other than the rim of the insertion portion. As the spacer is disposed in an air passage between the fins, a problem is caused in that ventilation resistance increases in the heat exchanger and the ventilation resistance further increases during operation under the condition that outside air has a low temperature, where frost increases from the spacer used as a base point. Not only the spacer prevents drainage of condensation water or meltwater of frost through the air passage between the fins but also a problem is caused in that heat transfer performance of the fins reduces as a hole is provided in the plate surface of the fin.

In Patent Literature 3, by raising the portion of the rim of the insertion portion for the flat tube, which is a portion that faces the long side of the section of the flat tube, the spacer is formed. In recent years, however, as the thickness of the flat tube has been reduced, the width of the insertion portion is small and hence, it is difficult to raise the spacer from the plate surface of the fin up to a required height. In a case where the height of the spacer from the plate surface is insufficient, the interval between the fins disposed next to each other is small. Drainage properties of condensation water may thus reduce and ventilation properties may be reduced by, for example, the clogging of the air passage when frost forms. A problem therefore is caused in that the heat exchanger does not effectively produce heat exchange performance.

SUMMARY

The present disclosure has been made to solve the above-mentioned problems, and it is an object of the present disclosure to provide a heat exchanger, a heat exchanger unit, and a refrigeration cycle apparatus where deterioration in drainage properties and ventilation properties is prevented, an air passage is not easily clogged when frost forms, and both defrosting properties and heat exchange performance are achieved.

A heat exchanger according to one embodiment of the present disclosure includes a flat tube and a plurality of fins that are each a plate having a plate surface extending in a longitudinal direction and in a width direction orthogonal to the longitudinal direction. The plate surface intersects a pipe axis of the flat tube. The plurality of fins are arranged at an interval from one another. The plurality of fins each have an insertion portion in which the flat tube is inserted, a first spacer formed at a rim of the insertion portion and maintaining the interval, and a second spacer formed at a portion of the plate other than the rim of the insertion portion and maintaining the interval. The first spacer is positioned at one end portion in a longitudinal direction of a section of the rim of the insertion portion, and the section is perpendicular to the pipe axis of the flat tube.

A heat exchanger unit according to another embodiment of the present disclosure includes the above-mentioned heat exchanger, and a fan configured to send air to the heat exchanger. The above-mentioned first spacer is positioned upwind of the above-mentioned second spacer in a direction of a flow of air sent to the heat exchanger.

A refrigeration cycle apparatus according to still another embodiment of the present disclosure includes the above-mentioned heat exchanger unit.

According to an embodiment of the present disclosure, with the above-mentioned configuration, the interval between the fins is appropriately maintained. It is therefore possible to prevent the clogging of the air passage when frost forms, and drainage properties of meltwater are ensured during the defrosting process. Further, as the first spacer is positioned at an end portion of the insertion portion in the longitudinal direction of the flat tube, it is possible to prevent the reduction of ventilation properties between the fin and the flat tube. Resistance against frost and drainage properties of the heat exchanger and the heat exchanger unit are therefore enhanced while heat exchange performance is maintained.

