JPH0554938U - Air conditioner - Google Patents

Abstract

(57) [Abstract] [Purpose] To improve the static pressure-air volume characteristics during heating and frosting, and also to improve the beat noise due to the interference between blower fans. [Structure] A second blower fan is further arranged in series on a rotary shaft of a first blower fan arranged in parallel, and one of the first and second blower fans is of an axial flow type and the other is of the other. The flow direction of the first blower fan and that of the second blower fan are opposite to each other, and the number of blades of the first blower fan and the number of blades of the second blower fan are changed. Make a difference.

Description

[Detailed description of the device]

[0001]

[Industrial application]

 The present invention relates to an air conditioner in which two or more blower fans are arranged in parallel.

[0002]

[Prior Art]

 In recent years, various demands have arisen with the spread of air conditioners at home. One of them is a demand for improving the interior quality by making the indoor unit built-in, and the other is a demand for improving the exterior quality of the outdoor unit. When hanging the outdoor unit under the eaves or balcony of the home, we want to make the height of the outdoor unit as low as possible. In addition, for multi-type outdoor units that connect multiple indoor units, there is a demand for a slim type to maximize the appearance and appearance. In order to meet these demands, the number of outdoor units of air conditioners, which have a horizontally long configuration or a vertically long configuration by arranging small blowers in parallel, is increasing.

[0003]

[Problems to be solved by the device]

 However, in the outdoor unit of the conventional air conditioner described above, the air volume becomes about twice as much due to the parallel arrangement of the small blowers, but since the static pressure remains almost unchanged, the slope of the characteristic curve of static pressure-air volume becomes gentle. In particular, due to the frosting phenomenon when the heating temperature is low and the outside air temperature is low, there is a disadvantage that the air flow rate is significantly reduced and the heat exchanger performance is degraded even with a small amount of ventilation resistance. In addition, there was a problem of howling noise due to the interference frequency f = N · Z / 60 (Hz) of the rotating sound represented by the product of the number of blades Z and the rotating speed N (rpm).

The present invention solves the above-mentioned conventional problems, and can improve the inconvenience of the static pressure-air volume characteristic curve due to the parallel arrangement of a plurality of blowers, and also improves the beat noise due to the interference between the blowers. The purpose is to provide an air conditioner that can do so.

[0005]

[Means for Solving the Problems]

 In order to solve the above problems, an air conditioner of the present invention includes two or more first blower fans facing a fin-tube heat exchanger, and an electric motor for rotating the first blower fan. In addition to being arranged in parallel, the second blower fan is arranged in series on the same axis as at least one first blower fan of the two or more first blower fans.

In addition, one of the first and second blower fans of the air conditioner of the present invention is configured as an axial flow type and the other is configured as a mixed flow type. Further, in the air conditioner of the present invention, the blower rotation direction of the first blower fan and the blower rotation direction of the second blower fan are fan-shaped so that the blower rotation directions are opposite to each other.

Further, the number of blades of the first blower fan and the second blower fan of the air conditioner of the present invention are made different.

[0008]

[Action]

 With the above configuration, if the second blower fan is further arranged in series on the rotation axis of the first blower fan arranged in parallel, the air flow rate will not change much, but the static pressure will be about twice, and the static pressure-air flow characteristic curve. The slope of the heat exchanger becomes steeper and the air flow rate will not decrease with a small amount of ventilation resistance, and the heat exchanger capacity will no longer decrease due to the frosted state of the outdoor unit during heating, unlike the conventional case. This is a great improvement in ability. Further, if the first blower fan is of axial flow type and the second blower fan is of oblique flow type, the inclination of the static pressure-air volume characteristic curve becomes steeper. Furthermore, if the blowing rotation direction of the first blower fan and the blowing rotation direction of the second blower fan are made opposite to each other, the outlet of the flow of the second blower fan and the inlet of the flow of the first blower are The pressure rises in the vicinity, and the static pressure is further increased at the outlet of the first flow, and the static pressure-air volume characteristic curve becomes steeper. Further, since the number of blades of the first blower fan and the number of blades of the second blower fan are different, it is possible to improve the beat noise due to the interference between the first blower fans arranged in parallel.

[0009]

【Example】

 An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram of an air conditioner showing an embodiment of the present invention. In FIG. 1, a fin-tube heat exchanger 3 is arranged at the suction port 2 of the outer case 1, and the first blower fans 4a and 4b and the blower fan driving electric motors 5a and 5b are opposed to this. They are arranged in parallel. Further, a second blower fan 6a is arranged in series with the first blower fan 4a on the rotating shaft of the first blower fan 4a.

Here, FIG. 2 shows a characteristic diagram of static pressure (P) -air volume (Q). If the blower fan 4a has a characteristic of p1-q1 at a certain rotation speed, for example, N = 750 rpm, and the blower fan 4b has a characteristic of p1 -q2, when the blower fans 4a and 4b are operated, that characteristic is obtained. The curve becomes p1-q4 (q4 <q3 = q1 + q2). In the case of simultaneous operation, as is clear from the characteristic curve, the air volume is about twice as low as that in single operation, but since the static pressure remains almost unchanged, the slope of the curve becomes gentle and with a little ventilation resistance. The air volume will be significantly reduced, and the heat exchanger capacity will decrease at the time of heating operation and low outside air temperature.

However, in the present invention, since the second blower fan 6a is further arranged in series on the rotation axis of the first blower fan 4a, the characteristic curve of the second blower fan 6a is p 2 −q1. Then, when the blower fans 4a, 4b, and 6a are operated simultaneously, the characteristic curve becomes a curve of p3-t1-q4 (p3≈p1 + p2) having the displacement point t1. The slope of the characteristic curve becomes steep on the left side of the displacement point t1, and even if the resistance is slightly increased, the air flow rate is not decreased, and the heat exchanger capacity can be greatly improved.

Further, one of the first and second blower fans 4a and 6a is of an axial flow type in which the blowing direction is forward, and the other is of a diagonal flow type in which the blowing direction is oblique. As a result, when the axial flow type blower fan 4a has a characteristic curve of p1-q1 and the mixed flow type blower fan 6a has a characteristic curve of p4-q5 as shown in FIG. The characteristic curve of is a curve of p5-t2-q4 having the displacement point t2. In this way, in the simultaneous operation of the series, the combined air volume hardly changes and the static pressure is added to it, so that the air volume depends on the axial-flow-type first blower fan 4a, and the static pressure is as high as possible. Use a mixed-flow fan 4b for the second fan to make the combined static pressure as large as possible to make the slope of the curve steeper, so that a slight increase in ventilation resistance does not decrease the air volume. It is the one.

Furthermore, when the blowing direction of the first blower fan 4a and the blowing direction of the second blower fan 6a are opposite to each other, the upstream second blower fan is formed. A pressure rise occurs in the vicinity A between the outlet of the flow of the fan 6a and the inlet of the flow of the first blower fan 4a on the downstream side, and as a result, the blower fan in the same blowing rotation direction at the outlet of the first blower fan 4a. Compared with the serial arrangement of, the combined static pressure becomes larger, the characteristic curve becomes steeper, and the decrease in air volume decreases with increasing ventilation resistance.

Further, even if the same blower fan and the same driving electric motor are used between the first blower fans 4a and 4b, there is a slight difference in the number of revolutions. Therefore, the number of blades Z and the number of revolutions N are different. A roaring sound is generated due to the interference frequency f = N · Z / 60 (Hz) of the rotating sound represented by the product of (rpm). This humming noise is noticeable because the interference frequency f is small, and in order to increase the interference frequency f, specifically, 10 Hz or more, a rotational speed difference is provided or a blade number difference is provided. Therefore, in the present invention, the number of blades of the second blower fan 6a arranged in series to increase the static pressure during the operation of the parallel blower fan is made different from the number of blades of the first blower fan 4a. Further, the driving electric motors 5a and 5b can be shared.

In the present embodiment, the two first blower fans 4a and 4b are provided in parallel, but two or more first blower fans 4a and 4b may be provided in parallel, and in the present embodiment, the first blower fan 4a is coaxial. Although the second blower fan 6a is arranged in series above, the second blower fan may be arranged in series in the first blower fan 4b as well, and two or more first blower fans may be arranged in series. The second blower fan may be arranged in series on the same axis as at least one first blower fan of the fans.

[0016]

[Effect of the device]

 As described above, according to the present invention, the second blower fan is further arranged in series on the rotation axis of the first blower fans arranged in parallel, and one of the first and second blower fans is arranged. The axial flow type and the other type are oblique flow type, and the blower rotation directions of the first blower fan and the second blower fan are opposite to each other, and the first blower fan and the second blower fan are further arranged. By varying the number of blades of the heat exchanger, it greatly contributes to the improvement of the air flow-static pressure characteristics when the ventilation resistance is excessive, such as when the heat exchanger is frosted, and also, the beat noise due to the interference between the blower fans. It also greatly contributes to the improvement.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an air conditioner showing an embodiment of the present invention.

FIG. 2 is an air volume-static pressure characteristic diagram of the air conditioner of FIG.

[Explanation of symbols]

 3 Fin Tube Heat Exchanger 4a, 4b First Blower Fan 5a, 5b Blower Fan Drive Motor 6a Second Blower Fan

Claims (4)

[Scope of utility model registration request] 1. A two or more first blower fans facing a fin-tube heat exchanger, and an electric motor for rotating the first blower fan are arranged in parallel, and
An air conditioner in which a second blower fan is arranged in series coaxially with at least one first blower fan of the two or more first blower fans. 2. The air conditioner according to claim 1, wherein one of the first and second blower fans has an axial flow type and the other has a mixed flow type. 3. A fan shape in which the blow-out rotation direction of the first blower fan and the blow-out rotation direction of the second blower fan are opposite to each other in the blow-out rotation direction.
Air conditioner described. 4. The air conditioner according to claim 1, wherein the number of blades of the first blower fan is different from that of the second blower fan.