JPH0419396A - Multiblade fan - Google Patents

Abstract

PURPOSE:To reduce noises by providing a semi-circular part and a circularly bent part in an outer diameter direction on a section of a suction port of a suction casing, also providing a truncated conical side plate of an impeller, and reducing deviation of suctioned air to the side of a main plate of a blade. CONSTITUTION:In a multiblade fan, an impeller 4 is surrounded by a casing 7 made up of a volute casing 102, a main casing 103, a suction casing 6 having a suction port 5 whose section is determined by a semi-curcular part 10 and a bent part 12. The impeller 4 is composed by a blade 8, a disc-shaped main plate 13 having a circularly bent part 14 on the peripheral part thereof, and a truncated conical side plate 9. The blade 8 is truncated conical shape on its side of the side plate 9. When the impeller 4 is rotated, accordingly, air suctioned from a suction part (g) is abruptly changed in its direction forcibly from axial to radial direction, flowed along the sectional surface to the side of the side plate 9 against the tendency of deviating to the side of the main plate 13, and the deviation of air flow to the side of the main plate 13 is reduced. Air returning from an inner part (d) of the casing 7 to the suction part (g) is decreased.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to multi-blade fans used in air conditioning equipment and ventilation blowing equipment.

2. Description of the Related Art Conventionally, as shown in FIGS. 5 and 6, a multi-blade fan of this type includes a blade 110, an impeller 101 having a disk-shaped main plate 111 and an annular side plate 112, and this impeller. 1
01, a main casing 103, and a suction port 104 with a semicircular section and a straight section.
A casing 1 consisting of a suction casing 105 having
It was configured with 06.

Problems to be Solved by the Invention During operation, the conventional multi-blade fan sucks air from the suction port 104 when the impeller 101 rotates.
01, and is discharged from the discharge port 107 through the interior d of the casing 106. The air sucked through the suction port 104 is forced to make a sudden change in direction from the axial direction to the radial direction, but the direction cannot be completely changed, and the suction air is forced into the main plate 1 of the blade 110.
11 side, and the blade 110 on the side plate 112 side does not work effectively. On the other hand, when the rotation speed is increased to obtain the desired performance, the noise increases. Further, the backflow air A tries to return to the suction side a through the gap t between the suction port 104 and the impeller 101, and when it collides with the forward flow air B, a buzzing noise is generated. Further, there was a problem in that the flow was disturbed at the outlet of the impeller 101 on the main plate 111 side, resulting in a decrease in efficiency and generation of noise.

The present invention has been made with the above-mentioned problems in mind, and an object of the present invention is to reduce noise and improve efficiency in a multi-blade fan.

Means for Solving the Problems In order to achieve the above objects, the present invention provides a casing in which an impeller having blades, a main plate, and a side plate is formed, and a discharge port is formed by a spiral casing, a main casing, and a suction casing having a suction port. The suction port has a semicircular section and a bent section in the outer diameter direction, the side plate has a truncated conical shape, and the main plate has a diameter larger than the outer diameter of the blade on the outer periphery of the disc part. This is a multi-blade fan with a circular section on the main casing side.

Moreover, a plurality of openings are provided in the disk portion of the main plate, and a sound absorbing material is pasted on the main casing side so as to block the openings, thereby creating a multi-blade fan.

Effect: With this configuration, the deviation of the suction air blades toward the main plate side is reduced, the blades on the side plate side work more effectively than before, and the backflow air that returns to the suction side from the gap between the suction port and the impeller is reduced, and the impeller Turbulent flow on the outlet main plate side is reduced, and noise is reduced. In addition, the bias of the intake air blades toward the main plate side is reduced, and the side plate side blades work more effectively than before.
Backflow air returning to the suction side from the gap between the suction port and the impeller is reduced, turbulence on the main plate side of the impeller outlet is reduced, and the main plate also absorbs sound, reducing noise.

Embodiment First, an embodiment of the multi-blade fan of the present invention is shown in FIGS. 1 and 2.
This will be explained based on the diagram. Note that the same parts as in FIGS. 5 and 6 showing the conventional example are given the same numbers and detailed explanations are omitted. In the figure, 4 is an impeller, and this impeller 4 has a casing 7 consisting of a spiral casing 102, a main casing 103, and a suction casing 6 having a suction port 5 whose cross section is formed by a semicircular part 10 and a bent part 12. being surrounded. The impeller 4 has blades 8 and a circular portion 14 on the outer periphery.
The main plate 13 has a disc shape, and the side plates 9 have a truncated cone shape, and the end surfaces of the nine side plates of the blade 8 are also shaped like a truncated cone.

In the above configuration, when the impeller 4 rotates, air is sucked from the suction part g and the pressure is increased by the impeller 4, and the casing 7
The liquid is discharged from the discharge port 107 through the interior d. The air sucked in from the suction part g is forced to change direction rapidly from the axial direction to the radial direction, so it tends to be biased toward the main plate 13, but the suction port 5 has a cross section that is connected to the semicircular part 10 in the outer radial direction. Bend section 1
2, the flow also tends to flow toward the side plate 9 along the cross section, which reduces the bias of the flow toward the main plate 13g4, making the blade 8 work more effectively (the axial length increases. The air in the interior d has a higher pressure than the suction part g of the impeller 4 due to the pressure increasing action of the impeller 4, and tries to return to the suction part g through the gap f between the impeller 4 and the suction port 5. However, since the cross section of the suction port 5 has a bent portion 12 in the outer diameter direction, the backflow air e in the interior d of the casing 7 is carried away from the gap f along the inner surface of the bent portion 12. In addition, the nine side plates of the impeller 4, the end surfaces of the blades 8, and the side plates 9 are connected to the bent portion 12 of the suction port 5.
Since the truncated conical shape is parallel to the casing 7, the amount of backflow air returning from the interior d to the casing g is considerably reduced. In addition, since the raw board 13 has a circular portion 14,
The flow at the outlet of the main plate 13 of the impeller 4 is not disturbed.

Therefore, the desired performance can be achieved at low rotation speeds, the passing wind speed at the blades 8 is reduced, turbulent noise due to backflow air is reduced, and as shown in FIG. 7, noise can be lowered compared to the conventional multi-blade fan.

Next, another embodiment of the multi-blade fan of the present invention will be described based on FIGS. 3 and 4. Note that the same parts as in FIGS. 1 and 2 are given the same numbers and numerals, and detailed explanations are omitted. In the figure, 4 is an impeller, and this impeller 4 has a casing 7 consisting of a spiral casing 102, a main casing 103, and a suction casing 6 having a suction port 5 whose cross section is formed by a semicircular part 10 and a bent part 12. surrounded by The impeller 4 has a blade 8, a circular plate 14 on the outer periphery, a plurality of openings 15, and a sound absorbing material 16 attached to the main casing 103 so as to close the openings 15. It is formed by a main plate 13 and a truncated conical side plate 9, and the end of the side plate 9 of the blade 8 is also configured in a truncated conical shape.

In the above configuration, when the impeller 4 rotates, air is sucked from the suction part g, the pressure is increased by the impeller 4, and the air is discharged from the discharge port 107 through the interior d of the casing 7. The suction part g
Since the more sucked air is forced to change its direction rapidly from the axial direction to the radial direction, it tends to be biased towards the main plate 13 side.
2, the flow also tends to flow toward the side plate 9 along the cross section, which reduces the bias of the flow toward the main plate 13 and increases the effective axial length of the blade 8. Moreover, the pressure of the air in the interior d of the casing 7 is higher than that in the suction part g of the impeller 4 due to the pressure increasing action of the impeller 4. trying to go back to However, since the cross section of the suction port 5 has a bent portion 12 in the outer diameter direction, the backflow air e in the interior d of the casing 7 is carried away from the gap f along the inner surface of the bent portion 12. In addition, since the end face of the blade 8 on the side plate 9 side of the impeller 4 and the side plate 9 are configured in a truncated conical shape so as to be parallel to the bent portion 12 of the suction port 5, the inside d of the casing 7 is connected to the inside g. Returning backflow air is significantly reduced.

Further, the main plate 13 has a circularly curved portion 14, and a sound absorbing material 16 provided with a plurality of openings 15 is attached to the circular plate portion of the main plate 13, so that the main plate 14 of the impeller 4
The flow at the side outlet is undisturbed and sound is absorbed.

Therefore, the desired performance can be achieved at low rotation speeds, the passing wind speed at the blade 8 is reduced, turbulent noise due to backflow air and vortices is reduced, and as shown in Figure 8, noise is lower than that of conventional multi-blade fans. .

Effects of the Invention As is clear from the description of the embodiments above, according to the multi-blade fan of the present invention, the bias of the intake air toward the main plate side of the blades is reduced, and the side plate side blades work more effectively than before.
Therefore, noise is reduced. In addition, backflow air returning to the suction side from the gap between the suction port and the impeller is reduced, and turbulent noise at the main plate and outlet of the main plate is also reduced, improving efficiency and reducing noise. Effects can be obtained.

[Brief Description of the Drawings] Fig. 1 is a side sectional view of a multi-blade fan according to an embodiment of the present invention, Fig. 2 is a front view of the multi-blade fan, and Fig. 3 is a multi-blade fan of an embodiment of the present invention. FIG. 4 is a front view of the multi-blade fan, FIG. 5 is a side sectional view of the conventional multi-blade fan, FIG. 6 is a front view of the same multi-blade fan, and FIG. 7 is the invention of the present invention. FIG. 8 is a noise characteristic diagram of an embodiment of the same site and a conventional multi-blade fan. FIG. 4... impeller, 5... suction port, 6...
...Suction casing, 7...Casing,
8...Blade, 9...Side plate, 10.
...Semicircular part, 12, old...bent part, 13...
・・Main plate, 14・・Curved portion, 15・Old・・Opening, 16・・Sound absorbing material, 102・・Vircular casing, 103・・・Main casing, 1
07.Old...Discharge port. Agent's name: Patent attorney Shigetaka Awano, 1st name, 1st figure, 0G, 111th u0, 16th paste. Amount of contact (m'/hour) Figure 111 Jj. A completely familiar J. Counterfeit (quantity (lγhIur)

Claims (2)

[Claims] (1) An impeller having a blade, a main plate, and a side plate is surrounded by a casing in which a discharge port is formed by a spiral casing, a main casing, and a suction casing having a suction port, and the suction port has a semicircular cross section and an outer diameter direction. The side plate has a truncated cone shape, the end surface of the side plate side of the blade also has a truncated cone shape, and the main plate has a curved part on the outer periphery of the disc part, which is larger than the outer diameter of the blade, and has a curved part on the main casing side. A multi-blade fan with parts. (2) The multi-blade fan according to claim 1, wherein a plurality of openings are provided in the disk portion of the main plate, and a sound absorbing material is pasted on the main casing side so as to close the openings.