ES2625932T3 - Sirocco fan and air conditioning - Google Patents

Abstract

A sirocco fan, which includes: a scroll (6); a fan body (11) which is rotatably disposed in the volute (6) and includes a plurality of blades arranged in a cylindrical manner; a motor (2) for driving the fan body (11) in rotation, and a bell mouth (9) forming a suction opening of the volute (6), in which the volute (6) includes two portions in straight line (12, 13) approximately parallel to each other in an outer spiral-like shape thereof, and a rotation shaft (7) of the motor (2) is located closer to one of the portions in a straight line (12 , 13), which is located closer to a tongue portion (8) of the volute (6), characterized in that a center of rotation (P) of the fan body (11) is offset relative to a center (O) of the bell mouth (9) and the displaced position is adjusted to be closer to the straight line portion (12) located closer to the tongue portion (8) of the volute (6).

Description

DESCRIPTION

Sirocco fan and air conditioning Technical field

The present invention relates to a sirocco fan and an air conditioner in which noise is reduced and an air blowing characteristic is improved.

Background of the technique

Until now, in a sirocco fan, a reverse flow phenomenon is known, in which a part of the air flow that is blown from a spiral-shaped scroll flows from an external part of the sirocco fan to an internal part thereof. When the reverse flow phenomenon occurs, since a reverse air flow collides 10 with a suction air flow, not only a quantity of air blowing is reduced, but also a noise increases. Therefore, it has been devised that a shape of a bell mouth that forms a suction opening of the scroll is changed while dividing into areas in circumferential directions, so that this reverse flow phenomenon, or the like is suppressed ( see, for example, Patent Document 1). In addition, an example is also proposed, in which an auxiliary tongue portion is provided in addition to a tongue portion, so as to protrude from the tongue portion (for example, see Patent Document 2). A sirocco fan that shows all the features of the preamble of claim 1 are known from JP 2000-240594 A.

[Patent Document 1] Japanese Patent Application Not Examined Publication No. 9-126193 (Pages 4 and 5, Figure 1 and Figure 2)

20 [Patent Document 2] Japanese Patent Application Not Examined Publication No. 2006-138268 (Page 4, Figure 1 and Figure 3)

Disclosure of the invention

Problems to be solved by the invention

Meanwhile, in the air conditioner in which the hitherto known sirocco fan is mounted, 25 such problems have occurred, since an amount of blown air that is blown from the sirocco fan at a predetermined noise value is small and the performance of a heat exchanger is reduced, a compressor load is increased and a COP (performance coefficient) is reduced. In addition, if the amount of air blown from the air blown outside the sirocco fan is increased to suppress the decrease of the COP, the noise value is increased and an uncomfortable sensation is given to a user.

In the light of the problems described above, an object of the present invention is to provide a sirocco fan capable of obtaining a large amount of air blowing at a time of a predetermined noise occurrence, in other words, to provide a sirocco fan. capable of reducing a noise value and a number of revolutions of the sirocco fan, when a predetermined amount of air blowing is obtained, and the air conditioner provided with the sirocco fan.

35 Furthermore, another object of the present invention is to suppress a reverse flow phenomenon by designing a form of a volute, and thus reducing! the noise value while maintaining the predetermined amount of air blowing.

Means to solve the problems

A sirocco fan according to the present invention is described in claim 1.

Advantages

In accordance with the present invention, in the sirocco fan as described in claim 1 and including a volute, a fan body that is rotatably disposed in the volute and includes a large number of blades arranged in a cylindrical manner, and a motor for driving the fan body in rotation, the volute includes two straight-line portions that are approximately parallel to each other in an outer spiral-like shape thereof, and a motor rotation shaft is located closer to a of the two portions in straight line 45, which is located closer to a portion of the tongue of the scroll. In this way, the amount of air blowing can be increased at a time of a predetermined occurrence of noise and in a case of an air conditioner, a COP can be improved. Brief description of the drawings

[Fig. 1] Figure 1 is composed of a schematic plan view (a) and a schematic side elevation (b) illustrating an internal construction of an indoor unit of an air conditioner provided with a sirocco fan 50 in a first embodiment of In accordance with the present invention.

[Fig. 2] Figure 2 is a view illustrating a positional relationship between a center of a bell mouth and a

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center of a rotation tree in the first embodiment.

[Fig. 3] Figure 3 is a view illustrating a volute shape in a second embodiment.

[Fig. 4] Figure 4 is a perspective view showing a mounted body of a support that supports the motor, a fan motor and a fan body in a third embodiment.

[Fig. 5] Figure 5 is a perspective view showing the support for supporting the motor in Figure 4.

[Fig. 6] Figure 6 is a perspective view showing a housing in which an air flow duct is provided in the support that supports the engine.

[Fig. 7] Figure 7 is a schematic view illustrating a housing in which a rib is provided at both ends of a tongue tongue portion of the scroll in a fourth embodiment.

[Fig. 8] Figure 8 is a schematic side elevation illustrating a rib of Figure 7.

[Fig. 9] Figure 9 is a view illustrating a speed distribution in a blow opening of the sirocco fan.

[Fig. 10] Figure 10 is a view illustrating a reverse flow phenomenon in the blow opening of the sirocco fan.

Reference Numbers

1: sirocco fan 2: fan motor 3: heat exchanger 4: suction opening 5: blow opening 6: volute

7: rotation shaft 8: tongue portion 9: bell mouth 10: indoor unit 11: fan body 12: straight line portion 13: straight line portion 14: support that supports the motor 15: air flow duct 16: nerve

17: suction opening 18: blow opening 20: reverse flow area 22: flow

Best ways to make the invention

Next, a preferred embodiment of the present invention will be described with reference to the drawings.

First realization

Figure 1 is composed of a schematic plan view (a) and a schematic side elevation (b) illustrating

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an internal construction of an indoor unit of an air conditioner provided with a sirocco fan in a first embodiment in accordance with the present invention.

In figure 1, a reference number 10 indicates an indoor unit that constitutes an indoor air conditioner and is provided with a pair of sirocco fans 1 and 1, a fan motor 2 which rotatably drives these sirocco fans 1 and 1 simultaneously, and a heat exchanger 3 that performs a heat exchange operation with air that is blown from the sirocco fan 1. The sirocco fan 1 is provided with a spiral-shaped scroll 6, and a fan body that includes a large number of blades that are rotatably arranged in scroll 6 and arranged in a cylindrical manner. In the drawing, a reference number 4 indicates a suction opening for air, a reference number 5 indicates a blow opening for cold air or hot air, a reference number 7 indicates a rotation shaft of the fan motor 2 and a reference number 8 indicates a tongue portion.

The indoor unit 10 mentioned above is provided with a refrigeration circuit for a refrigerant, which is composed of a compressor, a condenser, an expansion valve and an evaporator, all of which are not illustrated, and is configured to perform an operation of refrigeration, a heating operation, or similar, in a room. In addition, an example of specifications of the present first embodiment is as follows: the sirocco fan 1 is configured to have a fan diameter $ 160 mm, a width dimension of 190 mm, the number of blades 40 and the heat exchanger 3 is provided with a 12-step heat transmission tube and an overall passage of the heat transmission tube is 12.7 mm and a step of the same is 20.4 mm, a length in an axial direction of the Heat transmission tube is 700 mm and a traction resistance AP1 is 23.1 V1.3 [Pa] (V: speed [m / s]). In addition, the indoor unit 10 is configured to have a depth of 680 mm, a height of 210 mm and a width of 960 mm.

The air in the room is aspirated from the suction opening 4 of the indoor unit 10 and is additionally aspirated from a suction opening of the volute 6 in an axial direction. The air, to which a dynamic pressure and a static pressure is applied by means of a set of cylindrical blades rotated in the volute 6 by means of the fan motor 2, is blown from a discharge opening that opens in an air path of the indoor unit 10. The air is heat exchanged with the heat exchanger 3 installed in the air trunk, and is blown from the blow opening 5 in the room while changing in hot or cold air.

Figure 2 is a view illustrating a positional relationship between a center of the rotation shaft of the fan motor and a center of a bell mouth 9 in the first embodiment of the present invention. A point O indicates the center of the bell mouth 9 and a point P indicates the center of the rotation shaft of the fan motor 2 (a center of rotation of the fan).

The volute 6 of the present first embodiment is provided with two straight-line portions 12 and 13 that are approximately parallel to each other on an outer spiral shape of the volute 6, and the center of the rotation shaft 7 of the fan motor 2 it is moved towards the straight line portion 12 located closer to the tongue portion 8 of the volute 6. That is, the center of rotation P of the fan is displaced with respect to the center O of the bell mouth 9 and the displaced position is adjusted to be closer to the straight line portion 12 located closer to the tongue portion 8.

In Table 1, a noise value and a number of revolutions are shown, under the conditions that an amount of air blowing that blows air from the indoor unit is 16 m3 / min and an OP length is set to be 0 mm and 2 mm.

Table 1: Noise value and speed at 16 m3 / min

 OP Length

 0 mm 2 mm

 Noise value (dB)

 45.8 45.3

 Number of revolutions (rpm)

 1103 1092

According to Table 1, it has been found that when the OP length is set to 2 mm, the noise valve and the number of revolutions can be reduced.

Next, the reason for this result will be explained. In Table 2, a maximum amount of air blowing between the blades is shown, under the conditions in which the length OP is set at 0 mm and the number of revolutions is 1103 rpm and that the length OP is set at 2 mm and The speed is 1092 rpm. Incidentally, the amount of air blowing is 16 m3 / min in both conditions.

Table 2: Maximum amount of air blowing between the blades at 16 m3 / min

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 OP Length

 0 mm 2 mm

 Maximum amount of air blowing between the blades (at 16 m3 / min)

 0.682 0.661

According to Table 2, it has been found that the maximum amount of air blowing between the blades at the OP length of 2 mm is smaller. A sound pressure energy is proportional to the sixth velocity power, and the noise value is expressed by the following mathematical formula:

SPL = l Logic (p / po) 2 [dB]

where p: acoustic pressure energy [Pa]: 2 * 10-5 [Pa], therefore, the noise value is reduced. That is, to reduce the energy of the acoustic pressure, it is effective to reduce the maximum speed, and in the event that a distribution of the amount of air blowing between the blades is uneven as in the sirocco fan, it is preferable to reduce a value maximum of the amount of air blowing between the blades.

Second example

Figure 3 is a view illustrating a form of the scroll in a second example of the present invention. Incidentally, in the present embodiment, the center of the bell mouth 9 is adjusted to the center of rotation of the fan motor 2 (in case the amount of displacement is zero).

The volute 6 is provided with two portions in straight line FH and EB that are approximately parallel to each other on the external spiral-type shape, and the shortest distance between the two portions in straight line that is approximately parallel to each other. as CG, an intersection point of a parallel line that is parallel with the straight line portions FH and EB of the volute and passes through the center O of the bell mouth 9 and the external shape of the volute is defined as a point A, a point of the outer shape of the volute, in which a distance between the external shape of the volute and the center of rotation O of a fan is maximum, is defined as a point B, points of intersection of a perpendicular line, which is perpendicular to the straight line portions FH and EB of the volute and passes through the center of rotation O of the fan, and the straight line portions FH and EB of the volute are defined as a point C and a point G, respectively, a radius of the ve ntilator is defined as R, and an angle formed by an OA segment and an OB segment is defined as 0.

As an FGHABCE curve illustrating a volute shape known so far, it forms a logarithmic spiral and the diameter of the fan is small compared to that of the present embodiment whose R / cG is adjusted to meet the formula of 0.72 <R / Cg <0.82. Therefore, the number of revolutions required to obtain a predetermined amount of air blowing is increased.

On the other hand, when the R / CG is increased, the number of revolutions required to obtain the predetermined amount of air blowing is reduced, but an EB segment is closer to the fan, so that the amount of air blowing is concentrated in a space between the blades that are close to the EB segment. This results in an increase in the noise value.

Therefore, when the R / CG increases and an AB curve is separated from the fan with respect to the logarithmic spiral, the amount of air blowing between the blades in the vicinity of the AB curve and the amount of air blowing between the Blades in the proximity of the EB segment is reduced in this way.

Table 3 shows the noise value and the number of revolutions in the amount of air blowing of 16 m3 / min of the air blown from the indoor unit (CASE 1) and (CASE 2).

Table 3: Noise value and number of revolutions at 16 m3 / min

 Case 1 Case 2

 Noise Value (dB)

 45.3 44.1

 Number of revolutions (rpm)

 1092 1056

As shown in Table 3, the sirocco fan in the present example that includes the volute shape whose condition is set as (OC-R) / R = 0.375 and 0 = 60 ° can reduce the noise value and the number of revolutions compared to the sirocco fan hitherto known to have the volute shape formed by the logarithmic spiral, increasing the R / CG and keeping the AB curve away from the fan.

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By the way, as for an upper limit value of (OC-R) / R, when a distance between the straight line portion EB of volute 6 and an outer circumferential end of the fan becomes 0.45 or more, it is reduced the amount of air blowing and the noise value is increased. Therefore, (OC-R) / R is adjusted to meet the formula of (OC-R) / R <0.45.

Third example

Figure 4 is a perspective view showing a case in which the fan body 11, the fan motor 2 and a support 14 supporting the motor are mounted, Figure 5 is a perspective view showing a case in that an air flow duct 15 is not formed in the support 14 supporting the motor, and Figure 6 is a perspective view showing a case in which the air flow duct 15 is formed in the support 14 It supports the engine.

In addition, Table 4 shows the noise value and the number of revolutions at the amount of air blowing of 16 m3 / min of the air blown from the indoor unit, in a case where the air flow duct It is present in the support that supports the engine and a case where the air flow duct is absent in it.

Table 4: Noise value and number of revolutions at 16 m3 / min

 Air flow hole of the support that supports the engine

 Present Absent

 Noise Value (dB)

 44.8 45.3

 Number of revolutions (rpm)

 1091 1092

According to Table 4, it has been found that although the number of revolutions barely changes, the noise value is further reduced in the event that the air flow duct 15 is present in the support 14 to support the engine. The reason is that although a static pressure fluctuation generated from the fan is transmitted to the support 14 to support the motor and, therefore, the static pressure fluctuation is generated on a wall surface of the support 14 to support the motor and generates the noise in the case where the air flow duct 15 is absent in the support 14 to support the motor, the static pressure fluctuation generated from the fan counteracts mutually in a space in the vicinity of the support 14 that supports the motor in the case where the air flow duct 15 is present in the support 14 that supports the motor and, therefore, the fluctuation of the static pressure on the surface of the wall of the support 14 that supports the motor is suppressed .

In addition, it is observed that there is no change in a suction space of the sirocco fan 1 even when the air flow duct 15 is arranged in the support 14 that supports the motor, because the number of revolutions hardly changes. Incidentally, the constitution, in which the air flow duct 15 is provided in the support 14 that supports the motor as described above, can be combined with the constitution of the first embodiment described above or the second realization.

Fourth example

Figure 7 is a schematic perspective view illustrating a case where a rib 16 is provided at each of the two ends of the tongue portion 8 of the scroll in the present example, and Figure 8 is a schematic side elevation of the same.

The nerve 16 adopts an approximately rectangular parallelepipedic shape and the following formula is satisfied: segment XY <segment XZ, in which a point in the nerve 16 more separated from the fan body 11 is defined as a point X, a point in a circular arc portion of the tongue portion 8 further separated from the fan body 11 is defined as a point Y, and a point on the rib 16 closest to the fan body 11 is defined as a point Z.

Also, in figure 9, a velocity component is shown that is perpendicular to a blow opening 18 in a case where the rib 16. is absent. In figure 9, an area of reverse flow 20 is indicated indicated by a broken line. in the blow opening 18, a flow towards an inner part of the fan from an outer part thereof. In figure 10, current lines are shown, which are formed at a time when smoke is infused from, for example, a segment 21 in the suction opening 17, to demonstrate a reverse flow phenomenon.

Table 5 shows the noise value and the number of revolutions at the amount of air blowing of 16 m3 / min of the air blown outside the indoor unit 10 in a case where the nerve is present and a case in the That the nerve is absent.

Table 5: Noise value and number of revolutions at 16 m3 / min

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 Nerve

 Present Absent

 Noise Value (dB)

 44.4 45.3

 Number of revolutions (rpm)

 1077 1092

As shown in Table 5, the noise value and the number of revolutions can be reduced by providing a nerve. The reason is that in a case where the nerve is absent and a flow-resistant element is present, such as a heat exchanger or the like, the higher the tensile strength of the resistive element, there is more reverse flow phenomenon. , in which the air flow is directed towards the inside of the fan from the blow opening 18, occurs in the blow opening 18 of the sirocco fan 1, as illustrated in Figure 9, and this becomes a cause of increased noise value and number of revolutions. That is, as illustrated in Figure 10, a flow of air blown from the spaces between the blades on one side of the main plate is directed towards both ends of the volute along the volute and in proximity to both ends. from the tongue portion 8, flows within a space between the tongue portion 8 and the fan body 11, without flowing into the blow opening 18. The air flow also flows in the spaces between the blades and is blown out of the spaces between the blades on the side of the main plate, so that a flow 22 is blown towards the outside of the volute. When such a flow occurs, the fluctuation of the static pressure on the surface of the wall increases in the proximity of both ends of the tongue portion and a flow occurs that passes through the spaces between the blades many times, and an amount of air blowing increases in the flow of air circulating inside the fan. In this way, the amount of air blowing of the air flow that passes through the spaces between the blades also increases. This results in the increase in the fluctuation of the static pressure on the surface of the blade and the increase in the noise value.

On the other hand, in a case where the nerve 16 is present, the flow of air blown out of the spaces between the blades on the side of the main plate is directed towards both ends of the volute along the volute. An amount of air flow that flows into the space between the tongue portion 8 and the fan body 11 in the vicinity of both ends of the tongue portion 8 can be reduced, without flowing into the blow opening 18. From this so, compared to the case where the nerve is absent, the noise value and the number of revolutions can be reduced as shown in Table 5. Incidentally, it is appropriate that the nerve 16 has a width in the range of 5 to 10 mm In addition, the constitution, in which the rib 16 of the present example is provided, can be combined with any of the constitutions of the first to third examples described above.

Claims (3)

1. A sirocco fan, which includes: a scroll (6); a fan body (11) which is rotatably disposed in the volute (6) and includes a plurality of blades 5 arranged in a cylindrical manner; a motor (2) for rotating the fan body (11), and a bell mouth (9) forming a suction opening of the volute (6), wherein the volute (6) includes two straight-line portions (12, 13) approximately parallel to each other in an outer spiral-like shape thereof, and a rotation shaft (7) of the motor (2) is located closer to one of 10 the straight line portions (12, 13), which is located closer to a tongue portion (8) of the volute (6), characterized in that a center of rotation (P) of the fan body (11) is offset relative to a center (O) of the bell mouth (9) and the displaced position is adjusted to be closer to the straight line portion (12) located closer to the tongue portion (8) of the scroll (6). The sirocco fan according to claim 1, wherein an air flow duct (15) is provided in a support (14) to support the motor (2). 3. The sirocco fan according to claim 1 or 2, wherein a rib (16) is provided at each end of the tongue portion (8) of the volute (6). 4. An air conditioner comprising a sirocco fan according to any one of claims 1 to 3.