JPH053760Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Field of Industrial Application) The present invention relates to an improvement of an axial flow blower.

(Conventional technology) In recent years, in outdoor units for air conditioning, etc. that use axial flow blowers, there has been a demand for higher static pressure in the internal axial flow blowers in order to withstand high internal resistance, and at the same time, it has also been required to significantly reduce noise during operation. This is becoming an issue. To solve these problems, as shown in FIG. 8, a differential user 8' is provided on the discharge side of the fan 1' and opens in a direction perpendicular to the fan rotation axis 6', thereby reducing the dynamic pressure of the fan 1'. A system that recovers static pressure has been proposed (Japanese Patent Application Laid-Open No. 1977-77200).
(see publication).

(Problems to be Solved by the Invention) In the case of the above-mentioned known example, since the discharge port 7' of the differential user 8' is opened in a direction perpendicular to the fan rotating shaft 6', it is difficult to adapt it to a floor-standing type. Since the fan guide 2' on the exit side of the fan 1' is bent at right angles to the centrifugal direction, separation of the blown air flow tends to occur, and the differential user 8'
The velocity distribution within the area also tends to be non-uniform.

This invention was made in view of the above points,
The aim is to achieve high static pressure and low noise in an axial flow blower by configuring it to smoothly guide the blowing airflow on the rotor blade outlet side and to expect the most effective differential user effect. This is the purpose.

(Means for solving the problem) In the present invention, as a means for solving the above problem, as shown in FIG.
..., a front fan guide 2 on the outer periphery of the fan 1 that partitions an inflow region and an outflow region, and a flat plate-shaped fan guide 2 located near the rear of the outlet of the fan 1 and perpendicular to the fan rotation axis 6. The rear fan guide 3 constitutes an axial blower, and the front fan guide 2 has a suction side guide portion 2b upstream of its minimum diameter portion 2a whose diameter gradually decreases in the flow direction,
Discharge side guide part 2 downstream from the minimum diameter part 2a
c becomes a diameter that gradually increases in the flow direction, and the minimum diameter portion 2a is located between the midpoint position 5a of the axial height of the rotor blade 5 and the tip side trailing edge position 5b. , the discharge side guide portion 2c
is provided at the rear in the flow direction and extends outward toward a discharge port 7 that opens in a direction substantially parallel to the fan rotation axis 6, while the outer peripheral edge of the rear fan guide 3 is connected to the front fan guide 2. The passage area is gradually expanded from the blowing side of the rotor blade 5 between the front and rear fan guides 2 and 3 to reach the discharge port 7 in a direction substantially parallel to the extending portion of the discharge side guide portion 2c. A differential user 8 is formed, and the diameter of the fan 1 is D, and the minimum diameter portion 2 of the front fan guide 2 is formed.
When the axial distance between a and the rear fan guide 3 is L, the outer diameter of the discharge port 7 is D', and the opening width of the discharge port 7 in the direction perpendicular to the fan rotation axis 6 is H, 0.15D≦ The settings are such that L≦0.3D, 1.2D≦D′, and 0.2D≦H.

(Function) In the present invention, the following effects can be obtained by the above means.

(1) Air flow W flowing centripetally from the suction side along the suction side guide portion 2b of the front fan guide 2
flows smoothly outward toward the discharge side along the discharge side guide portion 2c due to the Coanda effect. Therefore, the separation that occurs in the conventional example does not occur, and the tip side of the rotor blade 5, which performs a large amount of work, works effectively.

(2) When the minimum diameter portion 2a of the fan guide 2 is located between the midpoint position 5a of the axial height of the blade 5 and the tip side trailing edge position 5b, the Coanda effect is effectively exhibited. Ru.

(3) The discharge side guide portion 2c is extended toward the discharge port 7, and the outer peripheral edge of the rear fan guide 3 is extended approximately parallel to the front fan guide 2 to the discharge port 7, thereby forming a differential user 8 between the two. Furthermore, by defining the dimensional range of each part of the blower as described above, dynamic pressure recovery by the differential user 8 can be effectively performed.

(Embodiment) Hereinafter, an axial blower according to an embodiment of the present invention will be described with reference to FIGS. 1 to 7.

This axial flow blower includes a fan 1 formed of four rotor blades 5, 5... formed on the outer periphery of a circular hub 4, and a front surface provided on the outer periphery of the fan 1 to partition an inflow area and an outflow area. It is composed of a fan guide 2 and a flat plate-shaped rear fan guide 3 located at the rear of the discharge side of the fan 1 and perpendicular to the fan rotation axis 6.

The front fan guide 2 includes a suction side guide portion 2b whose diameter gradually decreases from the upstream side to the minimum diameter portion 2a in the flow direction, and a discharge side guide portion 2c whose diameter gradually increases from the minimum diameter portion 2a to the downstream side. The discharge side guide portion 2c is provided at the rear in the flow direction and extends in the centrifugal direction toward the discharge port 7 that opens in a direction substantially parallel to the fan rotation axis 6. The minimum diameter portion 2a of the front fan guide 2 is located at a distance of about 0.35H from the midpoint 5a of the axial height dimension H of the rotor blade 5 toward the tip side trailing edge position 5b. Note that the position of this minimum diameter portion 2a is
The position is not limited to the illustrated position, but may be between the midpoint position 5a of the rotor blade 5 and the tip side trailing edge position 5b. Further, the outer peripheral edge of the rear fan guide 3 has a discharge port 7 approximately parallel to the front fan guide 2.
A diff user 8 extending to the discharge port 7 is formed between the front and rear fan guides 2 and 3.

The diameter of the fan 1 is D, the axial distance between the minimum diameter portion 2a of the front fan guide 2 and the rear fan guide 3 is L, and the outer diameter of the discharge port is
D' and the opening width of the discharge port 7 in the direction perpendicular to the fan rotation axis 6 are set to H, 0.15D≦L≦0.3D 1.2D≦D' 0.2D≦H.

The reason why the above size range is required will be described below.

In FIG. 2, the axial distance L between the minimum diameter portion 2a of the front fan guide 2 and the rear fan guide 3 is plotted on the horizontal axis.
(based on the diameter D of fan 1), and the static pressure at the design air volume point (air volume Q = 24.5 m ³ /min) on the vertical axis.
A characteristic diagram showing Ps is shown. here,
The opening width H of the discharge port 7 in the direction perpendicular to the fan rotation axis 6 is 0.3D, and the outer diameter D' of the discharge port 7 is 1.8D. Therefore, in the case of L<0.15D, as shown in FIG. Due to the narrow axial width,
Since the air flow W blown out from the fan 1 has a high velocity, the bending loss due to bending in a substantially right angle direction becomes large, and the resulting static pressure Ps is extremely low because the differential user effect due to deceleration cannot be obtained. It's summery. Conversely, L>0.3D
In this case, as shown in FIG. 3B, since the axial width of the flow path 8a is wide, the rear fan guide 3 has an effect of preventing peeling near the front fan guide 2 in an appropriate size range; When the area is wide, this effect is lost and the static pressure Ps decreases. From this, the range of L in which the differential user effect can be expected is:
0.15D≦L≦0.3D, and within this range, the air flow W discharged from the fan 1 becomes a moderate contraction flow, and is smoothly discharged without separation within the diff user 8.

Figure 4 shows a characteristic diagram in which the horizontal axis shows the outer diameter D' of the discharge port 7 (based on the diameter D of the fan 1), and the vertical axis shows the static pressure Ps at the design air volume point. . Here, H=0.3D and L=0.25D. In the case of D′<1.2D, as shown in FIG. , diff user) 8, the flow direction is changed in the axial direction without being decelerated, resulting in a large bending loss and a low static pressure Ps.
Therefore, the range of D′ in which the differential user effect is recognized is
1.2D≦D′.

In FIG. 6, the horizontal axis is the fan rotation axis 6 of the discharge port 7.
A characteristic diagram is shown in which the opening width H in the direction perpendicular to , and the static pressure Ps at the design air volume point are plotted on the vertical axis.
Here, L=0.25D and D'=1.8D. However, in the case of H<0.2D, as shown in Figure 7,
The actual discharge width of the discharge port 7 becomes smaller, and as a result,
Both the velocity and the dynamic pressure of the air flow W at the discharge port 7 have increased, and the resulting static pressure Ps has decreased. Therefore, the range of the opening width H of the discharge port 7 is
0.2D≦H.

The operation of the axial blower constructed as described above will be explained.

The air flow W flowing centripetally from the suction side flows smoothly outward from the fan 1 along the discharge side guide portion 2c due to the Coanda effect.
The separation that conventionally occurs near the discharge side of the fan guide 2 and the trailing edge of the rotor blade 5 on the tip side is eliminated.

In addition, a differential user 8 is formed on the discharge side of the fan 1 and extends to the discharge port 7, and the dimensional range of each part of the blower is defined as 0.15D≦L≦0.3D 1.2D≦D′ 0.2D≦H Therefore, by appropriately exerting the differential user effect, it is possible to increase the static pressure and reduce the noise of the axial flow blower.

In addition, when extending the discharge side guide portion 2c in the front fan guide 2, as shown in FIG. However, even if the shape expands outward toward the discharge port 7 in a conical shape, the same effects as described above can be expected.

(Effect of the invention) As described above, according to the invention, the shapes of the front fan guide 2 and the rear fan guide 3 are devised, and the dimensional range of each part of the differential user 8 formed between the fan guides 2 and 3 is reduced. By specifying the optimum dimensions, the air flow W blown out from the fan 1 does not separate within the diff user 8, and
The air is smoothly discharged from the air, and a sufficient differential user effect can be expected, which has the practical effect of achieving higher static pressure, higher efficiency, and lower noise in the axial blower.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an embodiment of the axial flow blower of the present invention, and FIG.
Ps characteristic diagram, Fig. 3 A and B are explanatory diagrams showing the state of air flow outside the dimensional limited range in the P-Ls characteristic diagram of Fig.
D'-Ps characteristic diagram, FIG. 5 is an explanatory diagram showing the state of air flow outside the dimension limited range in the D'-Ps characteristic diagram of FIG. 4, and FIG.
Ps characteristic diagram, FIG. 7 is an explanatory diagram showing the state of air flow outside the dimensional limited range in the H-Ps characteristic diagram of FIG. 6, and FIG. 8 is a cross-sectional view of a conventional axial flow blower. . 1...Fan, 2...Front fan guide, 2a
...Minimum diameter part, 2b...Suction side guide part, 2c...
...Discharge side guide part, 3...Rear fan guide, 5
... Moving blade, 5a ... Middle point position, 5b ... Chip side trailing edge position, 6 ... Fan rotation axis, 7 ... Discharge port,
8...Deaf user.

Claims (1)

[Scope of claims for utility model registration] A fan 1 having a plurality of moving blades 5, 5...
a front fan guide 2 that is located on the outer periphery of the fan 1 and partitions an inflow region and an outflow region;
and a flat plate-shaped rear fan guide 3 located near the rear of the outlet and perpendicular to the rotation axis 6. It becomes a reduced diameter,
Discharge side guide part 2 downstream from the minimum diameter part 2a
c is made to gradually increase in diameter in the flow direction, and the minimum diameter portion 2a is located between the midpoint position 5a of the axial height of the rotor blade 5 and the tip side trailing edge position 5b. , the discharge side guide portion 2c
is provided at the rear in the flow direction and extends outward toward a discharge port 7 that opens in a direction substantially parallel to the fan rotation axis 6, while the outer peripheral edge of the rear guide section 3 is connected to the front fan guide 2. The passage area is gradually expanded from the blowing side of the rotor blade 5 between the front and rear fan guides 2 and 3 to reach the discharge port 7 in a direction substantially parallel to the extending portion of the discharge side guide portion 2c. An axial blower configured to form a differential user 8, wherein the diameter of the fan 1 is D, the axial distance between the minimum diameter portion 2a of the front fan guide 2 and the rear fan guide 3 is L, and the discharge port When the outer diameter of the discharge port 7 is D', and the opening width of the discharge port 7 in the direction perpendicular to the rotation axis 6 is H, the settings were set so that 0.15D≦L≦0.3D 1.2D≦D' 0.2D≦H An axial flow blower characterized by: