JPS6365840B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a cylindrical blower used in combustion equipment, household equipment, and the like.

As shown in Figures 1 and 2, a conventional blower of this type has a plurality of impellers b rotatably disposed within a cylindrical casing a between a disc-shaped upper plate b ₁ and a lower plate b ₂ . A number of blades c are fixed in a radial manner, and the upper and lower surface plates b ₁ and b ₂ and the outer end diameter of the blade c are formed to have the same size, and the blades are arranged close to the lower surface plate b ₂ of the impeller b. The upper surface plate _d1 of the return passage d provided is made equal to the outer diameter of the impeller b, and an annular day user space e is formed between the outer peripheral opening end of the impeller b and the return passage d and the inner peripheral surface of the casing a. It has a structure.

However, according to such a structure, the airflow flowing out from the outlet of the impeller b collides with the inner circumferential surface of the casing a and then becomes a flow with a velocity component mostly in the circumferential direction in the day user space e. Since the air circulates within the annular day user space, a large pressure loss occurs when it collides with the inner peripheral surface of casing a, and wall friction loss is caused by the inner peripheral surface of casing a in the circulating air flow. occurs,
Furthermore, when the air flow flows to the return passage d side, the velocity component in the radial direction must be directed in the axial direction, resulting in bending loss.

Furthermore, even when flowing into the return passage d,
A loss occurs due to the mismatch in the direction of the flow with respect to the inlet of the return passage, and the total air blowing pressure of the impeller a decreases significantly by the time it reaches the fan outlet f communicating with the return passage d, resulting in poor air blowing performance. For,
There were drawbacks such as the need to increase the size of the fan in order to obtain the fan pressure necessary to improve the characteristics of the combustion equipment.

In order to eliminate such drawbacks, as shown in FIG. A blower has been proposed in which the upper opening ends of these passages g are provided at predetermined intervals in the direction of the impeller b, and the lower opening ends thereof are connected to the return passage side.

However, according to such a structure, the starting end _g2 of the passage wall _g1 forming the spiral passage g is tangentially close to the outer periphery of the impeller b which rotates at high speed. The air flow starts at the starting end g ₂
When the impeller B is cut off momentarily, a siren sound with a frequency determined by the product of the number of blades and the rotation speed of impeller B is generated, and a silencer is required to suppress the generation of this siren sound. becomes. In addition, if the spiral passages g are formed independently in each of the annular spaces, the structure becomes complicated and the casing a needs to be enlarged, and the area of the passages that can be formed is restricted. The flow velocity increases, and when the air volume exceeds a certain level, the pressure loss increases in the spiral passage g, resulting in a decrease in fan pressure.

In addition, blowers have been devised to solve the above drawbacks by improving the structure of the impeller, but simply changing the shape of the impeller does not allow the pressure of the impeller to flow through without loss. However, since there is no ventilation path in place for this purpose, it is not possible to make any significant improvements.

In order to eliminate these drawbacks of conventional blowers, the present invention converts the dynamic pressure caused by the flow at the impeller outlet into pressure within the passage from the impeller outlet to the fan outlet, thereby reducing most of the kinetic energy of the flow. The present invention provides an air blower characterized by being configured to recover pressure without loss, making it possible to significantly improve fan performance by 150% compared to conventional fans.

The technical means consists of an impeller with an annular outlet opening in the axial direction and a return passage inlet of a return passage arranged downstream of the impeller, the inner end of which is equal to the outer diameter of the lower plate of the impeller; One side end surface is equal to the convex curved surface of the guide vane of the return passage, and the other side end surface is shaped to extend linearly in the radial direction from the outer end of the next guide vane,
Moreover, it has a simple structure in which the booster blade pieces that divide the return passage at the inner end of the return passage inlet are arranged in close contact with the convex curved surface that forms the back surface of the guide vane at the inner end of the return passage inlet. The recirculation loss of the flow in the day user space on the outer periphery of the impeller is improved by using an impeller having an annular outlet in the axial direction, and the annular outlet of this impeller and the return passage inlet are made to face each other, so that the flow loss at the return passage inlet is improved. The purpose is to improve the inflow loss, provide pressure boosting vanes in the return passage, and recover the pressure of the flow in the return passage.

Embodiments of the present invention will be explained with reference to the drawings: 1
is a cylindrical casing, with a top plate 2 integrally provided at its upper end, and an inlet 3 in the center of the top plate 2.
has been drilled. Reference numeral 4 denotes an electric motor disposed above the suction port 3, which is attached to a support fitting 5 fixed to the top plate 2. An impeller 7 disposed inside the casing 1 is attached to the lower end of the rotating shaft 6 by a fixing device. It is fixed by 8.

This impeller 7 includes a top plate 10 provided with an inlet 9 communicating with the suction port 3 in the center thereof;
a plurality of blades 1 which are spaced apart from each other at a constant distance downward from zero and have a blade exit angle of 50 to 110 degrees with a circular lower plate 11 to which the rotating shaft 6 is fixed at the center thereof;
2 are attached radially.

The upper surface plate 10 of the impeller 7 is formed to have a larger diameter than the lower surface plate 11, and is formed in a bowl shape with a gentle slope downward from the inlet 9 toward the outer periphery, and the outer periphery is curved downward. The lower end of the curve is located on the extension of the outer periphery of the lower plate 11 or slightly below, and an annular outlet 13 opening downward is formed between the lower end of the curve and the outer peripheral end surface of the lower plate 11. Further, a small gap is provided between the curved lower end of the upper surface plate 10 and the inner peripheral surface of the casing 1.

The blades 12 are formed in a planar arc shape, an S-shape, or a flat plate shape, and the upper and lower ends thereof are formed in a shape that follows the upper and lower surface plates 10 and 11 of the impeller 7.
0 and 11, and its outer end extends outward from the bottom plate 11 and is located at the annular outlet 13.

Reference numeral 14 denotes a return passage, which includes a circular upper passage plate 15 horizontally arranged below the lower plate 11 of the impeller 7 with a small gap therebetween, and a constant interval below the upper passage plate 15. It is composed of a passage bottom plate 16, a plurality of guide blades 17 radially arranged between the passage top plate 15 and the bottom plate 16, and a booster blade piece.

The return passage upper plate 15 is provided with return passage inlets 18 at a plurality of locations on its outer periphery, facing the annular outlet 13 of the impeller 7 with a gap therebetween and opening in the same axial direction as the annular outlet 13, The inner end circular arc surface 18a of the passage inlet 18 is provided on the outer diameter of the lower surface plate 11 of the impeller 7, that is, on a vertical plane equal to the inner end surface of the annular outlet 13, and the outer end opening is arranged on the upper surface plate 11 of the impeller 7.
0, that is, on a vertical plane equal to the outer end surface of the annular outlet 13, and one side end surface 18b.
is formed on the same curved end surface as the curve on the back side of the guide vane 17, and the other side end surface 18c is slightly inclined in the same direction as the radial direction from the outer end position of the next guide vane 17 adjacent to the guide vane 17. It is formed with a straight end face in the direction. Therefore, the number of the return passage inlets 18 and the guide vanes 17 are the same, and the opening width in the circumferential direction at the outer peripheral end of the return passage inlet 18 is equal to the dimension between the outer ends of the adjacent guide vanes 17, 17. It is something that exists. Further, both side end surfaces 18b and 18c of this passage entrance 18 are formed so as not to coincide with the outer ends of the blades 12 at the outlet of the impeller 7 on a vertical plane, so that the number and rotation of the blades 12 of the impeller 7 can be adjusted. The generation of siren sounds is suppressed by creating a time lag in the generation of siren sounds whose frequency is determined by multiplying the frequency by the number of siren sounds.

The guide vane 17 is connected to the impeller 7 as shown in FIG.
A return passage outlet 19 is curved in a substantially arc shape in the direction of rotation of the return passage outlet 19 and has an inner end located at the center of the passage bottom plate 16.
The guide vanes 17, 17 are located on the upper opening edge, and are closely fixed to the inner circumferential surface of the casing 1, integrally with the outer circumferential end surfaces of the top plate 15 and the bottom plate 16, and are independent between the adjacent guide vanes 17, 17. Return passage 14a
is formed to eliminate circulation and leakage of gas flow.

Further, the passage bottom plate 16 on which these guide vanes 17 are erected is gradually inclined downward from its outer peripheral end toward the return passage outlet 19, and the height of the guide vanes 17 is adjusted inwardly from the outer end according to the inclination. By gradually increasing the height of the return passage 14 toward the end, the flow velocity in the return passage 14 is gradually decelerated, the kinetic energy of the flow is converted into pressure, and the pressure is recovered. It has been done.

The guide vanes 17 and the return passage upper plate 15 are integrated by inserting locking claws 20 protruding from the upper ends of these guide vanes 17 into engagement holes 21 bored in the return passage upper plate 15. Although not shown, the lower end of the guide vane 17 is also fixed to the return passage bottom plate 16 with the same structure.

Reference numeral 22 denotes a booster blade piece, whose upper end is integrally connected to the inner end circular arc surface 18a of each passage inlet 18 of the return passage upper plate 15, and hangs downward at right angles to the return passage upper plate 15. One end surface of the guide blade 17 is brought into close contact with the back surface of the guide vane 17 over the entire height to form a passage concentric with the inner peripheral surface of the casing 1 in a part of the return passage 14, and the passage of the passage upper plate 15 is Entrance 1
This is to perform pressure recovery of the flow from 8.

This booster blade piece 22 is preferably provided at a position with a radius that is approximately equal to the outer diameter of the impeller lower plate 11, and its circumferential length (width) is also 60 to 60 mm larger than the circumferential length of the passage entrance 18. A length of 85% maximizes the pressure recovery effect.

To describe the operation of the embodiment configured as described above, when the electric motor 4 is started and the impeller 7 is rotated, airflow flows from the suction port 3 to the inlet 9 of the impeller 7, and the pressure increase effect of the impeller 12 is achieved. It flows in the centrifugal direction while increasing the pressure, and the flow is smoothly changed downward (in the axial direction) by the curved outer circumference of the upper surface plate 10 of the impeller 7 and flows out from the impeller outlet 13.

The flow velocity distribution at the impeller outlet 13 is approximately uniform because the inner and outer circumferential edges of the outlet 13 are on the same plane, and the unopened portions of the return passage upper plate 15 are disposed close to each other in parallel. The flow is divided into a plurality of passage entrances 18 formed in the return passage upper plate 15 and flows into the divided return passages 14a communicating with each passage entrance 18.

Since a booster blade piece 22 protruding from the outer surface of the guide blade 17 is provided at the entrance of each return passage 14a, the outer circumferential space of this booster blade piece 22 functions like a pressure air chamber, and the return passage The velocity of the flow from the inlet 18 is reduced once, and the static pressure is converted to increase the pressure. In other words, the pressure will be increased. Also,
By providing this pressure-boosting blade piece 22, the turbulent flow or fluctuation of the flow from the return passage inlet is made uniform, and the loss is improved. This results in a homogenized flow, which makes it possible to efficiently recover the pressure corresponding to the decrease in flow velocity after the booster vane piece, resulting in a higher pressure.

Furthermore, in this embodiment, the passage bottom plate 16 is inclined downward from the outer end toward the center in the flow direction, so that the flow can smoothly exit the passage without colliding strongly with the passage bottom plate 16 or being greatly restricted. 19
It is possible to reduce pressure loss.

Fig. 6 shows a comparison between the blower of the present invention shown in Fig. 4 and the conventional blower shown in Figs.
This shows a comparison of the pressure-airflow characteristics when the return passages were manufactured with the same number of guide vanes and each was operated at the same rotation speed of 2400 rpm, and the solid line represents the characteristics of one embodiment of the present invention. The broken line represents the fan characteristics of a conventional blower.

As is clear from this figure, according to the blower of the present invention, the impeller 7 has an annular outlet 13 in the axial direction, the shape of the return passage inlet 18 facing the annular outlet 13, and the shape of the return passage inlet 18. Due to the synergistic effect with the booster blade piece 22 arranged on the inner arcuate surface, the fan pressure is 1.5 times that of a conventional blower.
This makes it possible to achieve high pressure.

As described above, the present invention includes an impeller rotatably disposed within a casing, and a plurality of guide vanes curved in an approximately arc shape between a passage top plate and a passage bottom plate, which are placed close to the bottom of the impeller. A return passage formed in a radial manner is fixedly installed, a passage entrance communicating with the outlet of the impeller is opened at the outer periphery of the upper plate of the return passage, and a fan outlet is opened at the center of the passage bottom plate,
Furthermore, since this relates to a blower in which a booster blade piece is arranged on the convex curved surface side of the guide vane of the return passage, a passage upper plate is arranged close to the impeller, and the blades are placed on the outer periphery of this passage upper plate. Since the passage entrance is provided to communicate with the car outlet, the flow from the impeller quickly and smoothly flows into the passage entrance, preventing flow leakage or circulation, and preventing the flow from forming on the inner peripheral surface of the casing. It does not cause collision or friction loss with the wall surface, and therefore can greatly reduce pressure loss and enable efficient air blowing.

In addition, since the outlet of the impeller is parallel to and faces the entrance of the return passage and the starting end of the passage can be eliminated, the generation of siren noise can be almost completely eliminated. The structure can be formed so that leakage of flow can be prevented by the narrow gap between the two, which can simplify the structure.

Further, in the present invention, the guide vanes arranged radially in the return passage are curved in a substantially arc shape, and the booster vane piece is arranged on the convex curved surface side, so that the airflow flowing into the return passage is directed to the booster vane. The flow is rectified into a uniform flow by the piece, and the flow velocity is reduced, making it possible to increase the pressure by recovering pressure, and by guiding it smoothly to the passage outlet by the guide vane, it is possible to greatly increase the fan pressure. It is something.

[Brief explanation of drawings]

FIG. 1 is a partially cutaway perspective view of a conventional blower, FIG. 2 is a simplified sectional view thereof, FIG. 3 is a partially cutaway perspective view of another conventional blower, and FIG. 4 is an embodiment of the present invention. FIG. 5 is a partially cutaway perspective view showing an example, FIG. 5 is an exploded perspective view showing the constituent parts of the return passage, and FIG. 6 is a P-Q characteristic diagram of the present invention and a conventional blower. 1 is the casing, 3 is the intake port, 4 is the electric motor, 7
is an impeller, 9 is an inlet, 12 is a blade, 13 is an annular outlet, 14 is a return passage, 15 is a passage top plate, 16 is a passage bottom plate, 17 is a guide vane, 18 is a passage entrance, 19
is the passage exit.

Claims (1)

[Scope of Claims] 1. An impeller 7 having an upper plate 10 having a larger diameter than a lower plate 11 and an annular outlet 13 opening in the axial direction is rotatably disposed in a cylindrical casing 1, A return passage 14 in which a plurality of guide vanes 17 curved in the rotational direction of the impeller 7 are provided radially between a passage top plate 15 and a passage bottom plate 16 in close proximity to the lower side of the impeller 7.
A return passage inlet 18 communicating with the annular outlet 13 of the impeller 7 is opened at the outer periphery of the upper passage plate 15 of the return passage 14, and a return passage outlet 19 is opened at the center of the passage bottom plate 16. The blower is further provided with a booster blade piece 22 which is closely attached to the back surface of the guide blade 17 of the return passage 14 and hangs down approximately at right angles to the passage upper plate 15. 2 Return passage entrance 18 that opens in the passage upper plate 15
has a shape in which the inner circular arc surface 18a is equal to the outer diameter of the lower plate 11 of the impeller 7, and the outer end surface is equal to the inner diameter of the casing 1, and one side end surface 18b is the same as the convex side of the curved surface of the guide vane 17. 2. The blower according to claim 1, wherein the other side end surface 18c is equal to the curved surface and extends linearly in the radial direction from the outer end position of the next guide vane 17 in the rotational direction. 3. The blower according to claim 1 or 2, wherein the length in the circumferential direction of the booster blade piece 22 disposed in the return passage 14 is shorter than the minimum opening width in the circumferential direction of the return passage entrance 18.