Air conditioner and heat exchanger used therefor

Abstract: A heat exchanger mounted in an air condition is constructed such that at least one row of heat conduction pipe groups are arranged so as to obstruct an air passage. Each heat conduction pipe groups is constructed such that a plurality of heat conduction pipes 22 are arranged in parallel with each other and a fine wire 23 made of a metallic material having excellent heat conductivity is spirally wound around each adjacent heat conduction pipes 22. Thus, performances of the heat exchanger can be improved without a possibility that the air conditioner is designed with larger dimensions. In addition, the heat exchanger includes a plurality of heat conduction pipes 39 arranged in the form of at least one row with a constant distance between adjacent ones and a plurality of twisted wires 40. The twisted wires 40 are arranged so as to alternately come in contact with one side and opposite side of each heat conduction pipe 39 extending at a right angle relative to the row direction of each heat conduction pipe 39, and moreover, alternately come in contact with one side and opposite other side of each heat conduction pipe 39 extending in the longitudinal direction. With this construction, high heat conductivity can be realized, and an occurrence of clogging with dew droplets can be prevented while maintaining a heat conduction area.

Description: BACKGROUND THE INVENTION Field of the invention The present invention relates to an air conditioner comprising the features according to the preamble of claim 1. Description of the Related Art Fig. 25 is a vertical sectional view which shows a conventional air conditioner. Referring to the drawing, a suction grille 2 is formed on the front surface of a housing 1 as an air suction port. An air blow-off port 3 is formed on the lower part of the housing 1. An air passage 4 is formed so as to communicate the suction grille 2 with the air blow-off port 3. A filter 5 is disposed at the rear stage of the suction grille 2 in such a manner as to obstruct the air passage 4. In addition, a heat exchanger 6 is disposed at the rear stage of the filter 5 in such a manner as to obstruct the air passage 4. Further, a blower 7 is arranged at the rear stage of the heat exchanger 6 in the air passage 4, and a drain receiver 8 is disposed below the heat exchanger 6. In the drawing, an arrow mark A shows the flowing of external working fluid, e.g., air. Although illustration is neglected, a plurality of vanes are rotatably disposed in the air blow-off port 3 so as to change the direction of air blowing. Fig. 26 is perspective view of a heat exchanger for the conventional air conditioner, and Fig. 27 is a plan view which shows a plate fin for the conventional heat exchanger. The heat exchanger 6 is constructed such that a single heat conduction pipe 9 is turned several times and a large number of plate fins 10 are fixedly held in parallel with each other with a predetermined pitch in the axial direction of the heat conduction pipe 9. A plurality of cut-up pieces 10a are formed on each plate fin 10. Here, a copper pipe having a circular sectional shape and a diameter of 6 mm to 12 mm is used for the heat conduction pipe 9, and an aluminum plate is used for the plate fin 10. A working fluid B is caused to flow through the heat conduction pipe 9. Next, a mode of operation of the conventional air conditioner will be described below. When the blower 7 is driven, air A in the room is introduced into the housing 1 from the suction grille 2, passes through the air passage 4 and is blown off from the air blow-off port 3 into the room. At this time, when the air A passes through the filter 5 disposed to obstruct the air passage 4, dust is removed from the air A. And then, when the air A passes through the heat exchanger 6, heat exchanging is effected between the air A and the working fluid B flowing through the heat conduction pipe 9 to cool or heat the interior of the room. With the conventional heat exchanger 6, as shown in Fig. 28, an air-temperature boundary layer C is cut attributable to a front edge effect with the aid of the cut-up pieces 10a of the plate fin 10 when the air A passes by it. By cutting the air-temperature boundary layer C, heat conduction performances are elevated, resulting in performances of the air conditioner being improved. Fig. 29 is a vertical sectional view of another conventional air conditioner, and Fig. 30 is a plan view of a plate fin used for the air conditioner. A plurality of holes 11a are formed through the plate fin 11 so as to allow heat conduction pipes 9 to be inserted therethrough, and cutouts 11b are formed on the plate fin 10 at plural locations. The plate fin 11 is bent at the cutouts 11b so that the heat exchanger 6A exhibits a contour having bent parts. In addition, another suction grille 2 serving as an air suction port is formed also through the upper surface of the housing 1, and a filter 5 and a heat exchanger 6A are arranged in the housing 1 to obstruct the flowing of air sucked through the grilles 2 formed through the fore surface and the upper surface of the housing 1. With the conventional heat exchanger 6A, a heat conduction area is increased attributable to the bent contour to enhance performances of the air conditioner. To enhance the performances of the conventional air conditioner, the following measure are hitherto taken. Specifically, one of them is to improve heat conduction performances of the heat exchanger. Other one is to increase an area of the heat exchanger. Another one is to reduce an air pressure loss of the heat exchanger to increase a quantity of air passing past the heat exchanger. With the conventional heat exchanger 6, by cutting the air-temperature boundary layer C attributable to the front edge effect with the aid the cut-up pieces 10a formed from the plate fin 10, heat conduction properties are improved to enhance the performances of the heat exchanger. However, formation of the cut-up pieces 10a from the plate fin 10 leads to the result that an air pressure loss is increased. Thus, in the case that this heat exchanger is incorporated in the air conditioner, a quantity of air flowing is reduced with the same power consumed by the blower 7. Consequently, there arises a problem that an effect for enhancing the performances of the air conditioner is reduced. In addition, since the heat exchanger 6 has high rigidity due to the structure of the heat conduction pipes 9 and the plate fin 10 assembled together, the air conditioner has few degree of designing of the configuration. To increase a conduction surface by bending, the cutouts 11b should be formed by cutting out a part of the plate fin 11 like the heat exchanger 6A. In this case, there arises other problem that the air conditioner is fabricated at an increased cost. Increasing of the conduction area of the heat exchanger leads to the result that the housing 1 is designed with large dimensions, i.e., the air conditioner is designed with large dimensions. In addition, unless a size of the housing 1 is changed, there is a limit for increasing a heat conduction area. With the heat exchangers 6 and 6A, the plate fins 10 and 11 are dimensioned to have width of 10 mm or more to increase a heat condition area. However, widening of the width of the plate fins 10 and 11 leads to the result that the housing 1 is designed with large dimensions. Thus, there arises another problem that the air conditioner is designed with large weight and fabricated at an increased cost. In addition, with the heat exchangers 6 and 6A, since the structure of the whole heat exchanger is uniformly designed, pressure loss on the air side is equalized at the front surface, an air speed is reduced at the lowermost end part of the heat exchanger as well as at the part including no suction grille, and the air speed is fastened at other part rather than the foregoing ones. Consequently, the heat exchanger is not effectively used, performances of the air conditioner are degraded, and moreover, noisy sound is generated from the air conditioner. Fig. 31 is a perspective view of a conventional heat exchanger as disclosed on an official gazette of Japanese Patent Laid-Open Publication NO. 61-153388, and Fig. 32 is a sectional view of the heat exchanger shown in Fig. 31. A plurality of heat conduction pipes 12 are arranged in parallel with each other with a predetermined distance between adjacent ones, and a fine wire 13 is arranged between adjacent heat conduction pipes 12 along the surface of these heat conduction pipes 12 so that the fine wire 13 is knitted like Japanese mat on the assumption that each heat convention pipe 12 serves as a warp and the fine wire 13 serves as a weft. In the drawings, reference character A denotes an external working fluid, while reference character B denotes a internal working fluid. In Fig. 32, the flowing state of the external working fluid A is shown by arrow marks. When the fluid A collides against the fine wire 13, the flowing state of the fluid A is disturbed, and the fluid A located below the fine wire 13 flows in the transverse direction along the fine wire 13 as shown by arrow marks while rising up on the surface of the heat conduction pipe 12. As a result, the time when the fluid A comes in contact with the heat conduction pipe 12 is elongated. In this case, since the fine wire 13 has a very small diameter, it comes in contact with the heat conduction pipe 12 with a small contact area. For this reason, the contact area between the fluid A and the heat conduction pipe 12 is not reducibly affected by the fine wires 13, causing a heat conduction function to be effectively practiced. In this conventional example, since each fine wire 13 has a circular or elliptical sectional shape, the contact part with the heat conduction pipe 12 exhibits an arc-shaped contour so that point contact or line contact occurs between the fine wire 13 and the heat conduction pipe 12. Thus, a contact area between the fluid A and the surface of each heat conduction pipe 12 is not reducibly affected by the fine wire 13. Thus, a heat exchanger having a high heat exchanging efficiency is obtainable. However, since this conventional heat exchanger has a small width of 1 to 3 mm, although it has large heat conductivity compared with the heat exchanger including the plate fin 10 around the heat conduction pipe 9 as shown in Fig. 26, since the heat conducting area is small as represented by 1/10 or less, there arises a problem that a necessary quantity of heat exchanging can not be obtained. In the case that the temperature of the external working fluid (e.g., refrigerant) is lower than a dewing temperature of air, moisture in the air becomes dew droplets. At this time, dew droplets are held between the fine wires so that the space between the fine wires 13 is clogged with dew droplets. Since air does not sufficiently past the fine wires 13, a quantity of air flowing is reduced due to pressure loss. Thus, there arises a problem that a necessary quantity of heat exchanging is not obtained. FR-A-793 344 (published 22 January 1936) discloses a heat exchanger having pipes in which hot water or steam circulates. Wires extending tangentially to the pipes are welded to the pipes. CH-A-375 031 (published 31 March 1964) discloses a heat exchanger with coils of wire in contact with the pipes. DE-C-975 537 (published 2 September 1954) discloses a heat exchanger for a steam boiler in which serpentine coils of wire are welded to the tubes conducting the boiler fluid. EP-A-0 693 666 (published 24 Jan 1996) constitutes part of the state of the art only in accordance with Article 54(3)EPC) and discloses heat exchangers for an air conditioner which is not described. The heat exchangers include embodiments in which fine wires are spirally wound around each pair of adjacent heat conduction pipes in a row of such pipes. SUMMARY OF THE INVENTION The present invention has been made in consideration of the aforementioned problems to be solved. A first object of the invention is to provide an air conditioner which assures that high performance can be realized without any necessity that the air conditioner is designed with large dimensions and fabricated at an increased cost. A second object is to provide an air conditioner with a heat exchanger which assures that heat conduction area per unit area at the front surface of the heat exchanger can be increased, heat exchanging is not reduced even when the heat exchanger is used in a wetted state, and a necessary quantity of heat exchanging can be obtained. Accordingly the invention provides an air conditioner as set forth in claim 1, wherein the heat exchanger has at least one row of heat conduction pipes, which are arranged in parallel with each other with a predetermined distance between adjacent ones, and fine wires made of a metallic material having excellent heat conductivity are spirally wound around each pair of adjacent heat conduction pipes. It is to be noted that, for example, three successive pipes #1, #2, #3 constitute two pairs of adjacent pipes, i.e. pipe #1/pipe #2 and pipe #2/pipe #3. Each of these two pairs is spirally wound with fine wire, with the result that the two spiral windings overlap (since they have pipe #2 in common). It is also to be noted that the preamble of claim 1 is based on the above-mentioned Japanese Patent Laid-Open Publication No. 61-153388. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a vertical sectional view of an air conditioner constructed in accordance with a first embodiment of the present invention. Fig. 2 is a plan view which shows essential components constituting a heat exchanger for the air conditioner constructed in accordance with the first embodiment of the present invention. Fig. 3 is a plan view which shows essential components constituting a heat exchanger for an air conditioner constructed in accordance with a second embodiment of the present invention. Fig. 4 is a plan view which shows essential components constituting a heat exchanger for an air conditioner constructed in accordance with a third embodiment of the present invention. Fig. 5 is a plan view which shows essential components constituting a heat exchanger for an air conditioner constructed in accordance with a fourth embodiment of the present invention. Fig. 6 is a vertical sectional view which shows an air conditioner constructed in accordance with a fifth embodiment of the present invention. Fig. 7 is a horizontal sectional view which shows an air conditioner constructed in accordance with a sixth embodiment of the present invention. Fig. 8 is a vertical sectional view which shows an air conditioner constructed in accordance with a seventh embodiment of the present invention. Fig. 9 is a vertical sectional view which shows an air conditioner in accordance with an eighth embodiment of the present invention. Fig. 10 is a plan view which shows essential components constituting a heat exchanger for the air conditioner constructed in accordance with the eighth embodiment of the present invention. Fig. 11 is a partially exposed plan view which shows essential components constituting a heat exchanger for an air conditioner constructed in accordance with a ninth embodiment of the present invention. Fig. 12 is a side view which shows an air conditioner constructed in accordance with a tenth embodiment of the present invention. Fig. 13 is a exposed perspective view which shows a fine wire for an air conditioner constructed in accordance with an eleventh embodiment of the present invention. Fig. 25 is a vertical sectional view of a conventional air conditioner. Fig. 26 is a perspective view of a heat exchanger for the conventional air conditioner. Fig. 27 is a plan view which shows essential components constituting a plate fin for the conventional heat exchanger. Fig. 28 is a sectional view of the plate fin taken along line XXVIII - XXVIII in Fig. 27. Fig. 29 is a vertical sectional view which shows by way of other example the conventional air conditioner. Fig. 30 is a plan view which shows by way of other example essential components constituting a plate fin for the conventional heat exchanger. Fig. 31 is a perspective view of the conventional heat exchanger which shows by way of other example essential components constituting the heat exchanger. Fig. 32 is a sectional view which shows by way of other example the conventional heat exchanger. DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will now be described below by way of example, with reference to the accompanying drawings. Embodiment 1. Fig. 1 is a sectional view of an air conditioner constructed in accordance with a first embodiment of the present invention, and Fig. 2 is a plan view which shows essential components constituting a heat exchanger for the air conditioner. Similar components in Fig. 1 and Fig. 2 to those shown in Fig. 25 and Fig. 29 are represented by same reference numerals, and repeated description of these components is omitted. Referring to the drawings, a heat exchanger 20 includes a single row of heat conduction pipes (pipe group 21) and is disposed at the rear stage of a filter 5 in such a manner as to obstruct an air passage 4. The heat conduction pipe group 21 is such that a plurality of heat conduction pipes 22 (... 22p, 22q, 22r, 22s, ...) each having a diameter of about 1 mm are arranged in parallel with each other with a pitch of 4 mm between adjacent ones, and a fine wire 23 made of a metallic material e.g., copper or aluminum, having excellent heat conductivity and having a diameter of 0.5 mm or less, is spirally wound about each pair (22p, 22q; 22q, 22r; 22r, 22s; etc.) of adjacent heat conduction pipes 22. The adjacent fine wires 23 are spirally wound in the reverse direction, i.e., the inter-engaging windings are wound in opposite directions. The heat conduction pipe group 21 is constructed such that when the heat exchanger 20 is arranged in a housing 1, each heat conduction pipe 22 orients in the upward/downward direction (in the perpendicular direction in Embodiment 1). Here, a fine wire portion 23a represents that it is located on the upstream side relative to air A passing through the fines wires 23, while a fine wire portion 23b is located on the downstream side relative to the same. Next, a mode of operation of the air conditioner constructed in accordance with the first embodiment of the present invention will be described below. As a blower 7 is driven, air A in the room is sucked from a suction grille 2, passes through a filter 5 and is conducted to the heat exchanger 20. Heat exchanging is effected between the air A and a working fluid B flowing through each heat conduction pipe 22 of the heat exchanger 20, and subsequently the air A is blown off from a blow-off port 3. The air which has reached the heat conduction pipe group 21 of the heat exchanger 20 is conducted to the fine wire portion 23b side past the fine wire portion 23a side. At this time, the flowing of the air is accelerated, and each fine wire portion 23a serves as a turbulence promoting member, causing the flowing of the air A to be three-dimensionally disturbed. Thus, the flowing of air A in the heat conduction pipe group 21 becomes a turbulent flow. As a result, heat conduction is promoted, the surface of the heat conduction pipe group 21 exhibits a high heat conductivity, and air conditioning capability of the air conditioner can be elevated. Since the fine wire 23 is spirally wound around each pair of adjacent heat conduction pipes 22, no intersection occurs with the fine wire 23 in the cross-sectional area extending at a right angle relative to the axial direction of each heat conduction pipe 22 so that the space between the fine wires as viewed in the flowing direction of air A is enlarged. As a result, air pressure loss can be suppressively reduced and a quantity of air flowing per unit driving force of the blower 7 can be increased. Thus, performance of the air conditioner can be elevated. In addition, since the axial direction of each heat conduction pipe 22 is coincident with the perpendicular direction, in the case that the air conditioner operates as a cooler, when water droplets formed by condensation of moisture in the air A adhere to the surface of the heat exchanger 20, they flow toward the heat conduction pipes 22 along the fine wire 23, and subsequently, they are downwardly drained along the heat conduction pipes 22. Even when the heat exchanger 20 is used while its surface is get wetted, there does not arise a malfunction that the air pressure loss is increased. Further, since the heat exchanger 20 is constructed by heat conduction pipes 22 each having a diameter of about 1 mm and fine wires 23 each having a diameter of 0.5 mm or less, it can be dimensioned to have a small thickness of 1 to 2 mm, whereby there does not arise a necessity for enlarging the volume of the housing 1. Since the heat conduction pipe group 21 of the heat exchanger 20 is constructed such that heat conduction pipes 22 are arranged in parallel with each other and fine wire 23 is spirally wound around each pair of adjacent heat conduction pipes 22, the capability of the air conditioner can easily be adjusted by changing the pitch between each adjacent heat condition pipes 22 and the winding pitch of fine wire 23. Thus, productivity of the air conditioner can be improved and the cost of the air conditioner can be reduced. Embodiment 2. In the preceding embodiment, a single fine wire 23 is spirally wound around each pair of adjacent heat conduction pipes 22. In this embodiment, as shown in Fig. 3, two fine wires 23 are spirally wound around each pair of adjacent heat conduction pipes 22, while exhibiting the same advantageous effects as those in the preceding embodiment. In the second embodiment, the spiral winding direction of two fine wires 23 around the same pair of pipes 22 (first pair) is the same but the spiral winding direction of two fine wires 23 around each pair of pipes 22 sharing a pipe with the first pair, is reversed. Embodiment 3. In the first embodiment, a single fine wire 23 is spirally wound around each pair of adjacent heat conduction pipes 22 and the spiral winding direction of adjacent fine wires 23 is reversed. In the third embodiment, as shown in Fig. 4, a single fine wire 23 is spirally wound around each pair of adjacent heat conduction pipes 22 and the spiral winding direction of adjacent fine wires 23 is the same, while exhibiting same advantageous effects as those in each of the aforementioned embodiments. Embodiment 4. In the third embodiment, a single fine wire 23 is spirally wound around each pair of adjacent heat conduction pipes 22 and the spiral winding direction of each fine wire 23 is same. In the fourth embodiment, as shown in Fig. 5, two fine wires 23 are spirally wound around adjacent heat conduction pipes 22 and the spiral winding direction of each fine wire 23 is same, while exhibiting the advantageous effects as those in each of the aforementioned embodiments. Embodiment 5. Fig. 6 is a vertical sectional view of an air conditioner constructed in accordance with a fifth embodiment of the present invention. In this embodiment, another suction grille 2 is disposed on the upper surface of a housing 1 to serve as an air suction port. A filter 5 is disposed at the rear stage of the grilles 2 formed in the front surface and upper surface of the housing 1, and a heat exchanger 24 is arranged at the rear stage of the grilles 2. The heat exchanger 24 includes heat conduction pipe group which is constructed in the same manner as the heat conduction pipe group 21 for the heat exchanger 20 in the first embodiment. The heat exchanger 24 is constructed to include two bent portions 24a and 24b which are formed at two locations by bending respective heat conduction pipes along the plane extending at a right angle relative to the parallel extension surface of the heat conduction pipes inclusive of their center, and is disposed in such manner as to obstruct an air passage 4. Other structure rather than the foregoing one is same to that in the first embodiment. According to the fifth embodiment, since the air conditioner includes the heat exchanger 24 constructed in the same manner as the heat exchanger 20, the same advantageous effects as those in the first embodiment are obtainable. In addition, since the heat exchanger 24 includes two bent portions 24a and 24b, a heat conduction area can be increased and performances of the air conditioner can correspondingly be improved. Since the heat exchanger 24 is constructed by heat conduction pipes each comprising a copper pipe having a diameter of about 1 mm and fine wires each made of a metallic material, e.g., copper or aluminum and having a diameter of 0.5 mm or less, it has a high degree of design configuration. Thus, each heat conduction pipe can easily be bent at a low cost while suppressing enlargement of the volume of the housing 1. In the fifth embodiment, the heat exchanger 24 includes two bent portions 24a and 24b. However, the number of bent portions should not be limited only to two. Alternatively, the heat exchanger 14 may include three or more bent portions. Embodiment 6. Fig. 7 is a horizontal sectional view which shows the structure of an air conditioner constructed in accordance with a sixth embodiment of the present invention. In this embodiment, a heat exchanger 25 is arranged at the rear stage of a filter 5, and a motor 26 for driving a blower 7 is disposed in a housing 1. The heat exchanger 25 includes a heat conduction pipe group constructed in the same manner as the heat conduction pipe group 21 of the heat exchanger in the first embodiment, and the heat conduction pipe group is corrugated in the direction at a right angle relative to the axial direction of each heat conduction pipe as well as in the direction of parallel arrangement of the heat conduction pipes and is disposed in such manner as to obstruct an air passage 4. Other structure rather than the foregoing one is same to that in the first embodiment. According to the sixth embodiment, since the air conditioner includes the heat exchanger 25 constructed in the same manner as the heat exchanger 20, the same advantageous effects as those in the first embodiment are obtainable. In addition, since the heat exchanger 25 exhibits the corrugated configuration, a heat conduction area can be increased and performance of the air conditioner can correspondingly be improved. Since the heat exchanger 25 is dimensioned to have a small thickness of 1 to 2 mm, the air conditioner has a high degree of design of configuration. The heat exchanger 25 is dimensioned to have a thickness of 1/10 to 1/6 of that of the conventional heat exchanger 6. Thus, even when it is corrugated, the thickness of heat exchanger 25 can be reduced to be smaller than that of the conventional heat exchanger 6. Thus, enlargement of the volume of the housing 1 can be suppressed. Embodiment 7. Fig. 8 is a vertical sectional view of an air conditioner constructed in accordance with a seventh embodiment. In this embodiment, a heat exchanger 27 is disposed at the rear stage of a filter 5. The heat exchanger 27 includes heat conduction pipe group constructed in the same manner as the heat conduction pipe group 21 of the heat exchanger 20 in the first embodiment. This heat exchanger 27 is constructed in an arc-shaped configuration by archedly bending respective heat conduction pipes within the plane extending at a right angle relative to the parallel extension surface of the heat conduction pipes inclusive of their center axes, and is disposed in such manner as to obstruct an air passage 4. Other structure rather than the foregoing one is same to that in the first embodiment. According to the seventh embodiment, since the air conditioner includes the heat exchanger 27 constructed in the same manner the heat exchanger 20, the same advantageous effects as those in the first embodiment are obtainable. In addition, since the heat exchanger 27 is formed in the arch-shaped configuration, a heat conduction surface can be increased and performances of the air conditioner can correspondingly be improved. Since the heat exchanger 27 is constructed by heat conduction pipes each comprising a copper pipe having a diameter of about 1 mm and fine wires each made of copper or aluminum and having a diameter of 0.5 mm or less, the air conditioner has a high degree of design of configuration. The respective heat conduction pipes can easily be bent at a low cost, and enlargement of the volume of the housing 1 can be suppressed. Further, since the heat exchanger 27 is formed in the arc-shaped configuration, the gap between the heat exchanger 27 and the blower 7 is uniformalized across the whole length of the heat exchanger 27, and generation of noisy sound can be reduced by uniformalizing the air speed in front of the heat exchanger 27. Embodiment 8. Fig. 9 is a vertical sectional view which shows the structure of an air conditioner constructed in accordance with an eighth embodiment of the present invention, and Fig. 10 is a plan view which shows essential components constituting an heat exchanger for the air conditioner constructed in accordance with the eighth embodiment of the present invention. In the eighth embodiment, a heat conduction pipe group 21 constituting the heat exchanger 28 is constructed such that a winding pitch of a fine wire 23 is changeably determined corresponding to an air speed. In other words, the winding pitch of the fine wire 23 is set to a small value within a portion 28A having a high air speed and it is set to a large value within a portion 28B having a low air speed. Other structure other than the foregoing one is same to that in the first embodiment. Generally, as air is sucked from the suction grille 2 of the air conditioner, there arise two parts depending on the contour of the suction grille 2, one of them being a part having a high air speed and the other one being a part having a low air speed. Since a value representing a magnitude of noisy sound generated by the air conditioner is determined corresponding to the part having a highest air speed, when such speed distribution appears, the value representing a magnitude of nosy sound generated by the air conditioner is elevated. When it is intended to reduce the value representing a magnitude of noisy sound generated by the air conditioner, it is necessary that an air speed is lowered. This leads to the result that a quantity of air required for assuring a necessary quantity of heat exchanging can not be maintained, and performances of the heat exchanger are degraded. With the heat exchanger constructed in accordance with the eighth embodiment, since the fine wire 23 is wound with a small pitch at the part 28A having a high air speed, and the fine wire 23 is wound with a large pitch at the part 28B having a low air speed, an air speed in front of the heat exchanger can be uniformalized, the value representing a magnitude of noisy sound generated by the air conditioner can be reduced, and moreover, performances of the heat exchanger can be improved without any elevating of the value representing a magnitude of noisy sound. Embodiment 9. Fig. 11 is a partially exposed plan view which shows essential components constituting a heat exchanger of an air conditioner constructed in accordance with a ninth embodiment of the present invention. In this ninth embodiment, the heat exchanger is constructed by first, second and third heat conduction pipe groups 21a, 21b and 21c which are successively arranged from the upstream side to the downstream side as viewed in the air flowing direction. A winding pitch of a fine wire 23 is determined to have a large value in accordance with the order of the first heat conduction pipe group 21a, the second heat conduction pipe group 21b and the third heat conduction pipe group 21c. Other structure rather than the foregoing one is same to that in the first embodiment. In this ninth embodiment, as air A is sucked from the suction grille 2 and passes through the filter 5, first, heat exchanging is effected between the air A and a working fluid B passing through respective heat conduction pipes 22 of the first heat conduction pipe group 21a, subsequently, heat exchanging is effected between the air A and the working fluid B passing through respective heat conduction pipes 22 of the second heat conduction pipe group 21b, and moreover, heat exchanging is effected between the air A and the working fluid B passing through respective heat conduction pipes 22 of the third heat conduction pipe group 21c, whereby the temperature of the air A is lowered or raised up to a desired temperature and is blow off via the blow-off port 3. At this time, the most upstream heat conduction pipe group has an especially large quantity of heat exchanging, and a quantity of heat exchanging is increasingly reduced toward the downstream side. In other words, the first heat conduction pipe group 21a contributes mainly to cooling or heating of air. Since a winding pitch of fine wire 23 is set to a small value at the first heat conduction pipe group 21a, and air speed is increased, three dimensional turbulent becomes large, causing heat conduction to be promoted, so that a large temperature difference between before heat exchanging and after heat exchanging is realized. Since a winding pitch of the fine wire 23 is enlarged at the second heat conduction pipe group 21b, a quantity of heat exchanging is correspondingly reduced but pressure loss becomes small compared with the first heat conduction pipe group 21a. Since a winding pitch of the fine wire 23 is further enlarged at the third heat conduction pipe group 21c, a quantity of heat exchanging is further reduced compared with the first heat conduction pipe group 21a. In such manner, according to the ninth embodiment, since heat exchangers are arranged in parallel with each other in the spaced relationship in the form of three rows, a heat conduction area of the heat exchanger can be increased. In addition, a winding pitch of the fine wire 23 is successively increased from the upstream side to the downstream side of air A among three heat conduction pipe groups, increasing of the air pressure loss as the whole heat exchanger can be suppressed, and a quantity of air required for assuring a necessary quantity of heat exchanging can sufficiently be maintained. Embodiment 10. Fig. 12 is a side view of a heat exchanger for an air conditioner constructed in accordance with a tenth embodiment of the present invention. In this tenth embodiment, a lower distributor 30 and an upper distributor 31 are arranged at the lower parts and the upper parts of the first, second and third heat conduction pipe groups 21a, 21b and 21c. The lower distributor 30 includes a feeding port 30a for the working fluid B and a partition plate 30b, while the upper distributor 31 includes a discharging port 31a for the working fluid B and a partition plate 31b. Other structure rather than the foregoing one is same to that in the ninth embodiment. With the heat exchanger constructed in accordance with the tenth embodiment, as the working fluid B is fed to the lower distributor 30 from the feeding port 30a, it reaches the upper distributor 31 while passing through respective heat conduction pipes 22 of the first heat conduction pipe group 21a, then, it reaches the lower distributor 30 while passing through respective heat conduction pipes 22 of the second heat conduction pipe group 21b, subsequently, it reaches the upper distributor 31 while passing through respective heat conduction pipes 22 of the third heat conduction pipe group 21c, and finally, it is discharged from the discharge port 31b. Heat exchanging is executed between the working fluid B and the air A as the working fluid B flows through the respective heat conduction pipes 22. Here, description will be made below with respect to the case that the air conditioner performs cooling operation. While the working fluid B flows through the respective heat conduction pipes 22, it is evaporated by heat exchanging between the working fluid B and the air A. A quantity of heat exchanging between the working fluid B and the air A is increased as the flow passage is elongated more and more, and a quantity of evaporation of the working fluid B is increased. In the worst case, the working fluid B is completely vaporized and gasified at the tail of the heat conduction pipes 22, causing the heat exchanger not to contribute to cooling of the air A because of the dried state. When a part of the heat conduction pipe group constituting the heat exchanger is held in the dried state as viewed in the direction of flowing of the air A, the air A passing past this dried part is delivered to the air passage 4 as it is kept wet at a high temperature. When the air having a high temperature and a high humidity is condensed and liquidized by mixing with the air having a low temperature and a low humidity in the air passage 4, there appears a phenomenon that dew droplets are discharged from the blow-off port 3. Such phenomenon remarkably appears in the case that the air conditioner operates under the moist cooling condition that air has large enthalpy and a quantity of heat exchanging is large. According to the tenth embodiment, since the working fluid B flows from the first heat conduction pipe group 21a on the most upstream side to the third heat conduction pipe group 21c on the most downstream side via the second heat conduction pipe group 21b, the dried state arises in the heat conduction pipes 22 of the third heat conduction pipe group 21c, even if a dried state arises. Therefore, since the air A passing past the range where the third heat conduction pipe group 21c is held in the dried state is transformed into the state having a low temperature and a low humidity attributable to heat exchanging at the first and second heat conduction pipe groups 21 and 21b, an appearance of dew droplets discharging phenomenon can be prevented, resulting in a quality of heat exchanging being elevated. Embodiment 11. Fig. 13 is a exposed perspective view of a fine wire for an air conditioner constructed in accordance with an eleventh embodiment of the present invention. This eleventh embodiment is same to each of the aforementioned embodiments with the exception that the fine wire 33 has a star-shaped polygonal cross-sectional contour. According to the eleventh embodiment, since the fine wire 33 has a polygonal cross-sectional contour, an outer surface area of the fine wire 33 is enlarged compared with the fine wire 23 having a circular cross-sectional view even though it has a same cross-sectional area. Consequently, a heat conduction area can be enlarged, and, moreover, a quantity of heat exchanging can be increased. In the eleventh embodiment, the fine wire 33 has a star-shaped polygonal cross-sectional contour. However, the outermost end of the start-shaped cross-sectional area should not be limited only to a sharpened end. Alternatively, the outermost end may exhibit a semicircular contour. In each of the first to eleventh embodiments, each heat conduction pipe has a circular contour. However, the same advantageous effects are obtainable even when each heat conduction pipe has a polygonal cross-sectional shape. In each of the first to eleventh embodiments, it is assumed that each heat conduction pipe 22 constituting the heat condition pipe group for the heat exchanger has an axial direction which orients in the upward/downward direction. However, the same advantageous effects are obtainable when the heat conduction pipe 22 constituting the heat conduction pipe group has an axial direction which orients in the horizontal direction.

Claims: An air conditioner comprising: a housing (1) having an air suction port (2) disposed on at least one of a fore surface and an upper surface, an air blow-off port (3) disposed on a lower part and air passage (4) formed so as to communicate between the air suction port (2) and the air blow-off port (3); a filter (5) disposed at the rear stage of the air suction port (2) so as to obstruct the air passage (4); a heat exchanger (20;24;25;27;28) arranged at the rear stage of the filter (5) so as to obstruct the air passage; and a blower (7) disposed at the rear stage of the heat exchanger in the air passage (4); wherein the heat exchanger has at least one heat conduction pipe group (21) arranged so as to obstruct the air passage (4), the heat conduction pipe group comprising a row of heat conduction pipes (22) which are arranged in parallel with each other with a predetermined distance between adjacent ones and fine wires (23) made of a metallic material having excellent heat conductivity, the fine wires (23) being in the form of windings in contact with the heat conduction pipes (22); characterised in that the fine wires (23) are spirally wound around each pair (22p,22q; 22q,22r; 22r,22s) of adjacent heat conduction pipes (22). An air conditioner as claimed in claim 1, wherein the sectional contour of the heat conduction pipe group as viewed in a direction of air flowing is bent at plural locations as viewed in the said direction. An air conditioner as claimed in claim 1, wherein the heat conduction pipe group is corrugated in a direction of obstructing air flowing. An air conditioner as claimed in claim 1, wherein a sectional contour of the heat conduction group as viewed in a direction of air flowing is formed in a arc-shaped contour. An air conditioner as claimed in claim 1, wherein there is a reduction of the pitch of parallel arrangement of the heat conduction pipes (22) and/or the pitch of winding of the fine wire (23) at a location of the heat conduction pipe group (21) where a high speed part of air flowing in the air passage (4) is obstructed, and an increase of the pitch of parallel arrangement of the heat conduction pipes (22) and/or the pitch of winding of the fine wire (23) at a location of the heat conduction pipe group (21) where a low speed part of the air flowing in the air passage (4) is obstructed. An air conditioner as claimed in claim 1, wherein a plurality of said heat conduction pipe groups (21a,21b,21c) constituting the heat exchanger are arranged as viewed in a direction of air flowing through the air passage, and there is an increase in the pitch of parallel arrangement of the heat conduction pipes (22) and/or the pitch of winding of the fine wire constituting each of the heat conduction pipe groups successively from the heat conduction pipe group (21a) located at the upstream side in the air passage toward the heat conduction pipe group (21c) located at the downstream side. An air conditioner as claimed in claim 1, wherein a plurality of said heat conduction pipe groups (21a,21b,21c) constituting the heat exchanger are arranged as viewed in a direction of air flowing through the air passage, and a working fluid, which flows in the heat conduction pipes, successively flows from the heat conduction pipe groups (21 a) located at the upstream side toward the heat conduction pipe group (21c) located at the downstream side. An air conditioner as claimed in any preceding claim, wherein the heat conduction pipes and/or the fine wire exhibit a polygonal sectional contour. An air conditioner as claimed in any preceding claim, wherein the axial direction of each of the heat conduction pipes (22) constituting the heat conduction pipe group (21) orients in the upward/downward direction.

Inventors: GOTOH TAKASHI, IIJIMA HITOSHI, TAKESHITA MICHIMASA, TANIMURA YOSHIAKI, YOSHIDA TAKAYUKI, YUMIKURA TSUNEO, GOTOH, TAKASHI, IIJIMA, HITOSHI, TAKESHITA, MICHIMASA, TANIMURA, YOSHIAKI, YOSHIDA, TAKAYUKI, YUMIKURA, TSUNEO, Gotoh, Takashi, c/o Mitsubishi Denki K.K., IIJIMA, HITOSHI, C/O MITSUBISHI DENKI K.K., Takeshita, Michimasa, c/o Mitsubishi Denki K.K., Tanimura, Yoshiaki, c/o Mitsubishi Denki K.K., YOSHIDA, TAKAYUKI, C/O MITSUBISHI DENKI K.K., Yumikura, Tsuneo, c/o Mitsubishi Denki K.K.
Applicants: MITSUBISHI ELECTRIC CORP, MITSUBISHI DENKI KABUSHIKI KAISHA
Application year: 1995
Main classification: F28F1
IPC codes: F28F1, F24F1