A fin and tube type heat-exchanger having a plurality of 6 mm or smaller heat tubes to allow refrigerant to move therein includes a plurality of cooling fins arranged at predetermined intervals, each cooling fin having a number of joint holes arranged in one or more stages, and a number of slits between the joint holes formed on each stage. Each slit has a projecting segment with an open portion corresponding to the direction of air flow and a pair of standing segments formed at both sides of the projecting segment for guiding the direction of air flow. The projecting segments project in the same direction from the surface of each cooling fin, and the slits are grouped in five rows. The heat tubes pass through and are jointed with the joint holes, respectively. The heat exchanger reduces pressure loss, optimizes heat-exchange efficiency, reduces manufacturing costs, and adapts to alternative refrigerants.

A fin and tube type heat-exchanger having a plurality of 6 mm or smaller heat tubes to allow refrigerant to move therein includes a plurality of cooling fins arranged at predetermined intervals, each cooling fin having a number of joint holes arranged in one or more stages, and a number of slits between the joint holes formed on each stage. Each slit has a projecting segment with an open portion corresponding to the direction of air flow and a pair of standing segments formed at both sides of the projecting segment for guiding the direction of air flow. The projecting segments project in the same direction from the surface of each cooling fin, and the slits are grouped in five rows. The heat tubes pass through and are jointed with the joint holes, respectively. The heat exchanger reduces pressure loss, optimizes heat-exchange efficiency, reduces manufacturing costs, and adapts to alternative refrigerants.

Disclosed is a fin and tube type heat-exchanger, which has a number of heat tubes of 6 mm or smaller to cause a reduction of the pressure loss and to prevent a drop in heat-exchange efficiency. Furthermore, the fin and tube type heat-exchanger can obtain the optimum heat-exchange efficiency, reduce the manufacturing cost and adapt to alternative refrigerants. The fin and tube type heat-exchanger comprises: a plurality of cooling fins arranged at predetermined intervals, each cooling fin having a number of joint holes which are formed on the surfaces thereof and arranged in at least one or more stages and a number of slits disposed at spaces between the joint holes formed on each stage in one surface of the cooling fins, each slit having a projecting segment which has an open portion opened correspondingly to the direction of air flow and a pair of standing segments formed at both sides of the projecting segment for guiding the direction of air flow, the projecting segments of the slits being projected in the same direction from the surface of each cooling fin, the slits being grouped by five rows; and, a plurality of heat tubes passing through the joint holes of each cooling fin and joined with the joint holes respectively, each heat tube having the diameter of 5.about.6 mm or smaller and allowing refrigerant to move therein.

Fin tube heat exchanger including heat exchange tubes each having an inside for flow of fluid therethrough, and sheets of cooling fins stacked at fixed intervals each having the heat exchange tubes passed therethrough in a row pitch L.sub.2, a direction along an air flow, in a range of 1.8 D.sub.0.ltoreq.L.sub.2.ltoreq.2.2 D.sub.0 and in a step pitch S.sub.2, a direction perpendicular to the air flow, in a range of 3.3 D.sub.0.ltoreq.S.sub.2.ltoreq.4.5 D.sub.0, where D.sub.0 denotes a diameter of the heat exchange tube, and projection pieces between the tubes opened for the air flow, thereby reducing a power consumption, noise, to improve reliability of the user, and saving production cost and making the heat exchanger compact.