JP2000145698A - Blower for cooling tower - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a blower for a cooling tower, capable of easily increasing air capacities by using a centrifugal fan without increasing noise, capable of improving efficiency and miniaturizing the cooling tower and capable of drastically reducing noise. SOLUTION: A centrifugal fan 2 is arranged on the downstream of a heat exchanging part of a cooling tower 10, and a casing 7 is arranged around the centrifugal fan 2. Since air capacities can be increased by increasing the total blade area through a process of increasing the number of blades in the centrifugal fan 2 and axially extending the width of each blade without increasing the peripheral velocity, air capacities can be increased without restraining the generation of noise, dynamic pressure of air to be discharged sideways from the centrifugal fan 2 can be converted into static pressure while being changed to the axial direction by the casing 7, both the improvement of cooling efficiency of the cooling tower 10 and the restraint of noise are achieved, and a short circuit can reliably be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a blower for a cooling tower, which blows air through a cooling tower, and more particularly to a blower for a cooling tower capable of obtaining a large amount of air with low noise.

[0002]

2. Description of the Related Art Generally, a cooling tower installed outdoors for the purpose of cooling water circulated in a factory or an air conditioner has a direct contact between air and water inside the cooling tower, and a temperature of water and air. It has an open-type cooling tower that combines the heat transfer utilizing the difference, ie, the cooling action by sensible heat, and the evaporation action of water itself, ie, the cooling action by latent heat (evaporation heat), and a heat exchanger, so that air and water do not come into direct contact. There is a closed cooling tower. In all cooling towers, forced ventilation, in which air is forced into contact with water or a heat exchanger using a blower, is generally used, and the ventilation system is a push-in type in which air is pushed in from the bottom of the cooling tower by a blower. ,
There is a suction type in which air is sucked from the lower part of the cooling tower by suction of a blower installed in the upper part of the cooling tower.

The required air pressure of a blower used for such a cooling tower is as low as about 7 to 15 mmAq. However, since a large air volume is required, an axial fan has been generally used as a blower. FIG. 8 shows a conventional example of such an axial flow fan. FIG. 8 is a schematic sectional view of a conventional cooling tower blower.

FIG. 8 shows a conventional cooling tower blower 100.
A hub 101b is rotatably supported at an upper position on the downstream side of the ventilation path of the cooling tower 10 and has a plurality of blades 101a as a center.
, A shaft 102 connected to the hub 101b and supporting the impeller 101, a motor 103 for rotating the impeller 101, and a motor 103
Belt 104 for linking the shaft 102 with the shaft 102, and the impeller 10
1 and a casing 105 surrounding the periphery of the casing 1.

[0005] The above-mentioned conventional cooling tower blower 100 has a feature that a large flow rate of gas can be pumped in spite of the cross-sectional area of the flow channel, and the efficiency is higher than other types of blowers.

[0006]

Since the conventional blower for a cooling tower is constructed as described above, it is necessary to increase the amount of air flowing to the cooling tower 10 to increase the cooling efficiency.
It was necessary to increase the total area of 01a and increase the rotation speed of the impeller 101 to increase the blowing capacity.

In order to increase the total area of the blades in the axial fan, there are methods such as increasing the number of blades and increasing the diameter of the impellers. In addition, it is difficult to increase the total area of the blades because noise must be increased due to an increase in the peripheral speed of the impeller if the diameter is increased. In addition, when trying to increase the air volume by increasing the rotation speed, the noise increases due to the increase in the peripheral speed of the impeller.Therefore, the rotation speed cannot be increased so much. For example, it is difficult to achieve both high efficiency of cooling by increasing the air volume and suppression of noise.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and the centrifugal fan can be used to easily increase the air volume without increasing the noise, so that the cooling tower can be made more efficient and smaller, and the noise can be reduced. It is an object of the present invention to provide a fan for a cooling tower, which can significantly reduce itself.

[0009]

A cooling tower blower according to the present invention is a cooling tower blower for performing forced ventilation in a cooling tower, wherein the blower is disposed downstream of a heat exchange portion of the cooling tower in a ventilation path. A centrifugal fan that sucks air from the axial direction through the heat exchange portion and sends out the air in a substantially centrifugal direction, and is formed of a substantially rectangular or rectangular opening-shaped substantially cylindrical body surrounding the periphery of the centrifugal fan. A casing having an end opening on the opposite side to the cooling tower heat exchange part side serving as an air discharge port, and a substantially plate-like body closing an upstream end of a ventilation path of the casing; And an airflow guide plate having an opening having a lip adjacent to the air suction side end portion with a predetermined gap therebetween at substantially the center of the substantially plate-shaped body. As described above, according to the present invention, the centrifugal fan is disposed downstream of the heat exchange portion, and the casing is disposed around the centrifugal fan. In the centrifugal fan, the number of blades is increased and the width of the blades is increased in the axial direction. By extending and increasing the total blade area to increase the air volume without increasing the peripheral speed, it is possible to increase the air volume while suppressing the generation of noise, and to reduce the dynamic pressure of the air discharged from the centrifugal fan to the side. The casing can convert the pressure to static pressure while changing its direction in the axial direction, improving both the cooling efficiency of the cooling tower and suppressing noise, and ensuring that the released air returns to the heat exchange section again (short circuit). Can be prevented.

The blower for a cooling tower according to the present invention may be provided, if necessary, at an intermediate portion of each side surface of the casing away from a corner portion thereof, protruding toward the outer periphery of the centrifugal fan, and having a tip portion of the centrifugal fan. It is provided with a substantially plate-shaped partition plate which is close to the outer periphery via a predetermined gap. As described above, according to the present invention, the space between the centrifugal fan and the casing side is divided into four by disposing the partition plate protruding from the casing, and the air gradually expanding between the centrifugal fan and the casing side is provided. By reliably configuring the passage, the airflows coming out of the centrifugal fan and going to the corners do not interfere with each other, the airflow direction is smoothly deflected from the centrifugal direction to the downstream side of the ventilation path, and The flow in the casing that goes is smoother, so that the loss can be reduced and the air can be discharged efficiently.

In the blower for a cooling tower according to the present invention, the casing is formed so as to expand from the air suction side of the centrifugal fan to the downstream side of the ventilation path as required. As described above, according to the present invention, the casing is formed in an expanded shape toward the downstream side of the ventilation path, and the air passage between the centrifugal fan and the side surface of the casing has a more smoothly expanded shape toward the discharge port. Thus, the air blown from the centrifugal fan can be discharged from the dynamic pressure to the static pressure while minimizing the energy loss.

In the blower for a cooling tower according to the present invention, if necessary, the centrifugal fan is formed by inclining an internal air passage at a predetermined angle to the downstream side of the ventilation path with respect to the centrifugal direction. As described above, according to the present invention, the direction in which the air is sent from the centrifugal fan is deflected in the direction inclined to the downstream side of the ventilation path with respect to the centrifugal direction, so that the inside of the casing facing the discharge port on the downstream side of the ventilation path. The flow becomes smooth,
The loss can be reduced and the air can be discharged efficiently.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A cooling tower blower according to an embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is a front view of an installation state of a cooling tower blower according to the present embodiment, FIG. 2 is an explanatory view of an installation state of the cooling tower blower according to the present embodiment, and FIG. 3 is a cooling tower according to the present embodiment. FIG. 4 is a vertical cross-sectional view of a cooling tower blower according to the present embodiment, and FIG. 5 is a schematic configuration diagram of an impeller of the cooling tower blower according to the present embodiment.

As shown in the drawings, the cooling tower blower 1 according to the present embodiment is disposed at the uppermost part of the cooling tower 10, and sucks air inside the cooling tower 10 and discharges the air to the outside. An impeller 2, which is a centrifugal fan, and a shaft portion 3 having one end fixed to the center of the impeller 2 and the other end provided with a pulley 3a.
A bearing 4 for rotatably supporting the shaft 3, and a pulley 3 disposed on the bearing 4,
a, a motor 6 for rotating the impeller 2, a casing 7 surrounding the impeller 2 and supporting the impeller 2 with the bearing 4 attached thereto, and an airflow guide plate disposed between the casing 7 and the cooling tower 10. 8 is provided.

The impeller 2 has a hub 2a to which the shaft 3 is fixed and which forms a central axis, and a main plate 2b which is formed in a substantially disk shape with an outer peripheral portion inclined upward and bolted to the hub 2a. A side plate 2c disposed substantially parallel to the main plate 2b, formed substantially disk-shaped like the main plate 2b with an outer peripheral portion inclined upward, and having an opening at the center serving as an air suction port; and a main plate 2b and a side plate. A plurality of blades 2d mounted in the middle of the center 2c so as to face backward in the rotation direction, a side plate 2c and a hub 2a.
And four stays 2e for connecting and reinforcing them. The impeller 2 has a configuration in which the outer peripheral portions of the main plate 2b and the side plate 2c are inclined upward, that is, on the downstream side of the ventilation path, and the air passage from the inside of the impeller 2 toward the outer periphery is inclined upward, so that air is centrifuged. It is sent out after being deflected in a direction inclined upward with respect to the direction, and can smoothly enter the casing 7.

The blades 2d are formed to be lightweight and strong by covering the outer periphery of the urethane foam core with FRP, and the blades have a wing-shaped bulge like an airplane wing. The blade strength is higher than that of a plate-like blade of equal thickness formed into a curved surface.

The casing 7 is formed of a cylindrical body having a square opening shape surrounding the impeller 2 at its center, the upper opening of the cylindrical body being an upward discharge port 7c, and each side wall 7a of the cylindrical body. Are arranged at a predetermined interval from the outer periphery of the impeller 2,
The configuration is such that four enlarged passage portions 7b whose cross-sectional areas gradually increase as the impeller 2 moves in the rotational direction from the position of the side wall 7a nearest the impeller 2 are formed. The casing 7 has a role of a scroll (swirl chamber) that collects the swirling flow of air from the outer periphery of the impeller 2 and discharges the swirling air to the outside.
The positions of the side walls 7a closest to the impeller are cutoff points.

The air flow guide plate 8 is formed of a substantially plate-like body that closes the upstream end of the ventilation path of the casing 7, and has a circular opening having a predetermined diameter in the center. While the rim of the blade is protruding upward, it comes close to the periphery of the air suction side end of the impeller 2 via a predetermined gap to prevent airflow from flowing from the cooling tower 10 to the casing 7 without passing through the impeller 2. is there.

Next, the ventilation operation of the cooling tower blower based on the above configuration will be described. When the impeller 2 is rotated by the motor 6, the side plate 2c facing the inside of the cooling tower 10 is formed.
The air inside the cooling tower 10 is sucked through the opening of the cooling tower 10. Here, by sucking the air inside the cooling tower 10, outside air is newly sucked into the cooling tower 10 from the side. The air sucked into the impeller 2 flows in the centrifugal direction along the blade 2d and is sent out of the impeller 2. Since the arrangement of the blades 2d in the impeller 2 is rearward, the flow in the impeller 2 is easy, and the blade 2d, which is a streamlined airfoil, has high lift and low resistance to the flow, so that the efficiency is improved. Good and low noise. Since the air flows out from the impeller 2 at a speed close to its peripheral speed, if the air is discharged from the discharge port 7c at a high speed as it is, the wasted kinetic energy becomes large, resulting in a large loss. In the embodiment, the kinetic energy of the air discharged from the impeller 2 can be converted into pressure energy and effectively recovered by turning the air in the enlarged passage portion 7b of the casing 7 while turning the air, thereby recovering the pressure. As a result, the discharge can be performed with less loss. The air that has been decelerated to recover the static pressure is smoothly discharged from the discharge port 7c into the outside air. Since the discharge port 7c is directed upward, the phenomenon that the discharged air is sucked into the cooling tower 10 again (short circuit) hardly occurs, and the outside air having a low temperature is always taken into the cooling tower 10.

As described above, the cooling tower blower according to the present embodiment uses the backward-facing blade fan, which is one of the centrifugal fans, and increases the number of blades and the width of the blades as compared with the axial-flow fan. Since it is possible to increase the blade area by extending in the direction, it is possible to greatly increase the air volume without increasing the peripheral speed, thereby realizing both improvement in cooling efficiency of the cooling tower and low noise. Further, the shape of the casing can be simplified, and the casing can be easily manufactured and the cost can be reduced.

In the blower for a cooling tower according to the above-described embodiment, the casing 7 is formed in a simple rectangular-opening cylindrical body. In addition, as shown in FIG. 7 may be formed as a truncated inverted pyramid-shaped cylindrical body whose upper part is widened with respect to the lower part, and the air passage between the impeller 2 and the side surface of the casing 7 is smoother toward the discharge port 7c. Because of the widened shape, the air delivered from the impeller 2 can be discharged from dynamic pressure to static pressure while minimizing energy loss. In addition to the casing 7, as shown in FIG. 7, four partition plates 9 protruding from the inner surface of the casing 7 toward the impeller 2 are provided, and a space between the impeller 2 and the inner surface of the casing 7 is provided. It is also possible to adopt a configuration in which the air passage is gradually divided between the impeller 2 and the inner surface of the casing 7 so that the air passage extending from the impeller 2 to each corner portion side of the casing 7 can be formed. The airflows to be directed do not interfere with each other, and the direction of the airflow is smoothly deflected from the centrifugal direction to the downstream side of the ventilation path, so that the loss can be reduced and the air can be efficiently discharged.

In the cooling tower blower according to the above-described embodiment, the impeller 2 is configured as a backward-facing blade fan. The impeller has an arc-shaped cross section and is short in the radial direction and long in the axial direction. A large number of blades (usually 36 to 64 blades) may be configured as a multi-blade fan mounted to face forward with respect to the rotation direction.
The blower can be made the smallest under the same air volume and pressure conditions. In addition, a radial fan consisting of a plurality of flat blades attached in the radial direction can be used.This makes it possible to simplify the blade structure, reduce costs, and increase blade strength and durability. It will be excellent.

[0023]

As described above, according to the present invention, a centrifugal fan is provided downstream of the heat exchange part and a casing is provided around the centrifugal fan. By extending the width in the axial direction and increasing the total blade area, it is possible to increase the air volume without increasing the peripheral speed, thereby increasing the air volume while suppressing the generation of noise, and discharging it to the side from the centrifugal fan The dynamic pressure of the air can be converted to static pressure while changing the direction in the axial direction by the casing. This improves the cooling efficiency of the cooling tower and suppresses noise, while returning the released air to the heat exchange section again (short circuit). (Circuit) This has the effect of reliably preventing the phenomenon.

Also, in the present invention, a partition plate protruding from the casing is provided to divide the space between the centrifugal fan and the casing side into four parts, and the space is gradually expanded between the centrifugal fan and the casing side. By reliably configuring the air passage, the airflows coming out of the centrifugal fan and going to the corner portions do not interfere with each other, and the airflow direction is smoothly deflected from the centrifugal direction to the downstream side of the ventilation path, and the discharge port This has the effect that the flow in the casing toward the air becomes smooth, the loss can be reduced, and the air can be discharged efficiently.

Further, in the present invention, the casing is formed so as to expand toward the downstream side of the ventilation path, and the air passage between the centrifugal fan and the side surface of the casing has a more smoothly expanded shape toward the discharge port. Accordingly, there is an effect that the air blown from the centrifugal fan can be discharged from the dynamic pressure to the static pressure while minimizing the energy loss.

In the present invention, the direction in which the air is sent from the centrifugal fan is deflected in a direction inclined to the downstream side of the ventilation path with respect to the centrifugal direction, so that the casing facing the discharge port on the downstream side of the ventilation path. Inside flow becomes smooth,
There is an effect that the air can be efficiently discharged by reducing the loss.

[Brief description of the drawings]

FIG. 1 is a schematic front view of an installation state of a cooling tower blower according to an embodiment of the present invention.

FIG. 2A is a left side view of an installed state of a cooling tower blower according to one embodiment of the present invention. (B) is a top view of the installation state of the cooling tower blower which concerns on one Embodiment of this invention.

FIG. 3 is a schematic configuration plan view of a cooling tower blower according to one embodiment of the present invention.

FIG. 4 is a sectional view taken along line AA of FIG. 3;

FIG. 5A is a longitudinal sectional view of an impeller of a cooling tower blower according to one embodiment of the present invention. (B) is a view on arrow B in FIG. 5 (A).

FIG. 6 is a longitudinal sectional view of a blower for a cooling tower according to another embodiment of the present invention.

FIG. 7 is a schematic configuration plan view of a cooling tower blower according to another embodiment of the present invention.

FIG. 8A is a schematic configuration plan view of a conventional cooling tower blower in an installed state. FIG. 7B is a cross-sectional view taken along the line CC of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1, 100 Cooling tower blower 2, 101 Impeller 2a, 101b Hub 2b Main plate 2c Side plate 2d, 101a Blade 2e Stay 3, 102 Shaft 3a Pulley 4 Bearing 5, 104 Belt 6, 103 Motor 7, 105 Casing 7a Side wall 7b Enlarged passage 7c Discharge port 8 Air flow guide plate 9 Partition plate 10 Cooling tower

Continued on the front page (51) Int.Cl. ⁷ Identification code FI Theme coat II (reference) F04D 25/08 304 F04D 25/08 304E 29/00 29/00 A 29/30 29/30 A C 101 101 29/42 29/42 HF term (reference) 3H022 AA02 BA01 BA02 CA50 DA03 DA11 DA19 DA20 3H032 AA10 3H033 AA02 AA18 BB02 BB06 CC01 CC03 CC04 DD03 DD04 DD05 DD06 DD09 DD26 EE03 EE06 EE08 EE11 EE19 3H034 AA02 CB03 DD03 EE06 EE08 EE11 EE12 EE18

Claims (4)

[Claims] 1. A cooling tower blower that performs forced ventilation in a cooling tower, wherein the cooling tower blower is disposed downstream of a heat exchange part of the cooling tower in a ventilation path, and sucks air from the axial direction through the heat exchange part.
A centrifugal fan that sends out in a substantially centrifugal direction, and is formed of a substantially rectangular or rectangular opening-shaped substantially cylindrical body surrounding the periphery of the centrifugal fan, and is opposite to the cooling tower heat exchange part side of the substantially cylindrical body. A casing having an end opening serving as an air outlet, and a substantially plate-like body closing an upstream end of the ventilation path of the casing, and a predetermined clearance around an air suction side end of the centrifugal fan. And an airflow guide plate having an opening having an edge adjacent to the plate-like member formed substantially at the center of the substantially plate-shaped body. 2. The cooling tower blower according to claim 1, wherein an intermediate portion of each side surface of the casing remote from a corner portion protrudes toward the outer periphery of the centrifugal fan, and a tip end portion of the blower has an outer peripheral portion. A cooling plate blower, comprising a substantially plate-shaped partition plate adjacent to the cooling tower via a predetermined gap. 3. The cooling tower blower according to claim 1, wherein the casing is formed so as to expand from the air suction side of the centrifugal fan toward the ventilation path downstream. Blower for cooling tower. 4. The blower for a cooling tower according to claim 1, wherein the centrifugal fan is formed by inclining an internal air passage at a predetermined angle downstream of the ventilation path with respect to a centrifugal direction. A blower for a cooling tower.