JP6673702B2 - Cooling tower with axial blower - Google Patents

Description

  The present invention relates to a cooling tower equipped with an axial blower, and in particular, a plurality of blades formed respectively on the rotating shaft, the front surface of the blade on the positive pressure side having a concave shape, and the back surface of the blade on the negative pressure side having a convex shape. The present invention relates to a cooling tower provided with an axial blower arranged and configured.

  Conventionally, as shown in FIG. 4, a cooling tower 1 includes a filler 2 configured by arranging a number of plate members 20 in parallel, a water supply tank 4 for supplying treated water to the filler 2 from above, and a side of the filler 2. And a drainage tank 5 into which treated water cooled by air flowing in the filler 2 flows, and is adjacent to an upper end of the filler 2. The air seal material 3 is disposed in a gap, specifically, in a gap between the upper end of the filler 2 serving as a passage for outside air and the water supply tank 4.

  The gantry 10 of the cooling tower 1 in which the filler 2 is disposed guides the outside air to a side surface (a side surface orthogonal to the plate 20) serving as an outside air intake, and also supplies the outside of the treated water supplied to the filler 2. A louver 11 for preventing scattering into the air and entry of foreign matter is attached.

  A water supply tank 4 is disposed above the filler 2 above the gantry 10, and an axial blower 6 as a suction fan is disposed above the opposed fillers 2, 2. Is disposed, and a drainage tank 5 common to the fillers 2 and 2 is disposed below (see, for example, Patent Document 1).

JP 2013-11400 A

  By the way, conventionally, as shown in FIG. 5, a blade front surface 61a on the positive pressure side is formed in a substantially planar shape, and a blade back surface 61b on the negative pressure side is formed in a convex shape, as shown in FIG. An axial blower configured by disposing a plurality of blades 61X on the rotating shaft 60 has been used.

As a result of analyzing the air flow around the blade 61X of the axial blower 6 of the cooling tower 1, on the blade back surface 61b on the negative pressure side, the air flow past the convex top of the blade back surface 61b is The wings 61X are separated from the surface of the wing rear surface 61b and flow as they are at the rear end of the wing rear surface 61b in the rotational direction of the wing 61X. At the position of the rear end, a vortex is generated, resulting in turbulence.

  Then, when the turbulent flow occurs, the substantial negative pressure surface area of the blade back surface 61b of the blade 61X is reduced, which is a factor for reducing the static pressure of the axial blower 6.

  The present invention focuses on the separation phenomenon of the air flow on the blade back side which is the suction side of the blade of the conventional cooling tower axial flow blower, and reduces the reduction due to the separation of the substantial suction surface area of the blade back surface of the blade. It is an object of the present invention to provide a cooling tower provided with an axial blower capable of reducing the static pressure value and increasing the static pressure value.

  In order to achieve the above object, a cooling tower provided with an axial blower of the present invention is an axial blower configured by arranging a plurality of blades having a convex back surface on the negative pressure side on a rotating shaft. In the cooling tower provided with the first blade, the first convex portion is formed such that the convex shape on the back surface of the blade, which is the negative pressure side of the blade, is located at a position 20 to 45% of the width of the blade from the tip in the rotational direction of the blade. %, A second convex portion is formed, a concave portion is formed between the first convex portion and the second convex portion, and an imaginary line connecting both ends of the blade in the width direction with respect to the width of the blade. The thickness of the wing in the direction orthogonal to the direction of the first convex portion is 6 to 20%, and the thickness of the wing is 2 to 10% at the position of the second convex portion.

  In this case, the thickness of the blade in a direction orthogonal to an imaginary line connecting both ends in the width direction of the blade with respect to the width dimension of the blade is the position of the concave portion between the first convex portion and the second convex portion, It can be formed to be thinner than the thickness at the position of the first protrusion, thicker than the thickness at the position of the second protrusion, and 4 to 15%.

  Further, the wings may have the same cross-sectional shape.

  Further, the wing may be made of FRP or aluminum.

  Further, the wing may be formed in a hollow shape.

  Further, the wing may have a surface coated with a wear-resistant material.

According to the cooling tower provided with the axial blower of the present invention, disposed on the rotating shaft of the axial blower provided in the cooling tower, a plurality of blades having a convex back surface on the negative pressure side, the said blade, The convex shape on the back surface of the wing is formed such that a first convex portion is formed at a position of 20 to 45% of a width dimension of the wing from a tip in a rotational direction of the wing, and a second convex portion is formed at a position of 65 to 85% of the wing. A concave portion is formed between the first convex portion and the second convex portion, and the thickness of the wing in a direction orthogonal to an imaginary line connecting both ends in the width direction of the wing with respect to the width dimension of the wing is equal to the first thickness. 6 to 20% at the position of the convex portion, and 2 to 10% at the position of the second convex portion, so that the position of the top of the first convex shape on the back surface of the wing can be changed. The air flow separated from the surface of the wing rear surface is reattached by the second convex shape, so that the position of the rear end of the wing rear surface in the rotational direction is changed. Vortex does not occur, it can be prevented from becoming turbulent. As a result, it is possible to reduce the reduction of the substantial negative pressure surface area on the back surface of the blade due to peeling, increase the static pressure value, make the twist angle smaller than that of the conventional blade, and make the rotation speed of the axial blower Therefore, it is possible to provide a cooling tower provided with an axial blower with low energy consumption and low noise.

  Further, the thickness of the wing in a direction orthogonal to an imaginary line connecting both ends in the width direction of the wing with respect to the width dimension of the wing is the first position at the position of the concave portion between the first convex portion and the second convex portion. Is formed to be thinner than the thickness at the position of the convex portion, thicker than the thickness at the position of the second convex portion, and 4 to 15%, so that the air flow on both surfaces of the wing becomes turbulent. Can be prevented.

  Further, by making the blades have the same cross-sectional shape, the blades can be easily manufactured by a pultrusion molding method or an extrusion molding method. Towers can be provided.

  Further, by making the wings made of FRP or aluminum, it is possible to easily manufacture a lightweight, high-strength wing by a pultrusion molding method or an extrusion molding method.

  In addition, since the blades are formed in a hollow shape, the weight of the blades can be reduced, so that it is possible to provide a cooling tower including an axial blower with low energy consumption.

  Further, by providing a surface of the blade with a wear-resistant material, a cooling tower having a durable axial blower can be provided.

It is a perspective view showing one example of an axial fan used for a cooling tower provided with an axial fan of the present invention. It is a cross-sectional view of the blade of the coaxial blower. It is a schematic diagram which shows the flow of the air around the blade | wing of a coaxial flow blower. It is explanatory drawing of the cooling tower provided with the axial blower. It is a schematic diagram which shows the flow of the air around the blade | wing of the conventional axial flow fan.

  Hereinafter, an embodiment of a cooling tower provided with an axial blower of the present invention will be described with reference to the drawings.

  1 to 3 show an embodiment of a cooling tower provided with the axial blower of the present invention.

  This cooling tower 1 is, like the conventional cooling tower 1 shown in FIG. 4, an upper part of the gantry 10, more specifically, above the space between the packing materials 2, 2 disposed opposite to each other, as a suction fan. An axial blower 6 is provided.

  The axial flow blower 6 is configured by arranging a plurality of (four in the present embodiment) blades 61 on a rotating shaft 60 that is rotated by an electric motor via a boss member 60a. .

  The wing 61 is configured such that a shaft member (not shown) extending radially from the boss member 60a is inserted into the inside of the wing 61 from an end face on the center side, and the wing 61 is fixed to the shaft member using a screw member 60b. .

Further, the wing 61 has an end face plate 62 slightly larger than the end face shape of the wing 61 provided on the outer end face of the wing 61.
By disposing the end face plate 62, it is possible to prevent air from escaping to the outer peripheral side of the blade 61, and to increase the efficiency of the axial blower 6.

  In the present embodiment, the blade 61 has a cross-sectional shape, as shown in FIG. 2, in which a blade front surface 61a on the positive pressure side is combined with a convex shape and a concave shape, and a blade rear surface 61b on the negative pressure side. Are formed in a convex shape, respectively.

  More specifically, the convex shape of the blade back surface 61b, which is the negative pressure side of the blade 61, is set to 20 to 45%, more preferably 25 to 35% of the width dimension W of the blade 61 from the tip in the rotation direction of the blade 61 ( In this embodiment, the first convex portion is located at a position (approximately 30%) (L1 / W) (the position of the apex; the same in the present specification). 80% (about 75% in this embodiment) (L3 / W) position (the position of the vertex; the same in the present specification), the second convex portions are formed, and the first convex portion is formed. 45 to 65%, more preferably 50 to 60% (about 55% in this embodiment) (L2 / W) between the portion and the second convex portion (refers to the position of the valley. The same applies in the specification.), A temporary portion connecting both ends in the width direction of the wing 61 with respect to the width dimension W of the wing 61. The thickness of the wing 61 in the direction perpendicular to the line L is 6 to 20% at the position of the first convex portion, more preferably 10 to 15% (about 14% in the present embodiment) (T1 / W). 2 to 10% at the position of the second convex portion, more preferably 4 to 8% (in this embodiment, about 7%) (T3 / W), 4 to 15% at the position of the concave portion, More preferably, they are formed at 6 to 10% (about 8% in this embodiment) (T2 / W), respectively.

  In this case, the thickness of the wing 61 in the direction orthogonal to the imaginary line L connecting both ends of the wing 61 in the width direction with respect to the width dimension W of the wing 61 is such that the thickness of the concave portion between the first convex portion and the second convex portion. At the position, the thickness is smaller than the thickness of the first convex portion (T1 / W> T2 / W), and larger than the thickness of the second convex portion (T2 / W> T3 / W).

  The distance from the virtual line L in the direction orthogonal to the virtual line L connecting both ends of the blade 61 in the width direction with respect to the width dimension W of the blade 61 to the blade front surface 61a of the blade 61 is 2 at the position of the first protrusion. -10 to 10% (about 5% in this embodiment) (Da1 / W), -2 to 0% (about -1% in this embodiment) at the position of the second convex portion (Da3 / W). ), The distance to the blade back surface 61b is 0 to 5% (approximately 2% in this embodiment) (Da2 / W) at the position of the concave portion, and 5 to 20% (Da2 / W) at the position of the first convex portion. In this embodiment, about 10%) (Db1 / W), at the position of the second convex part 3-12% (about 7% in this example) (Db3 / W), at the position of the concave part At 4 to 15% (about 6% in this embodiment) (Db2 / W).

FIG. 3 shows the result of analyzing the flow of air around the blades 61 of the axial blower 6 of the cooling tower 1.
As apparent from FIG. 3, past the position of the top of the first convex of the blade suction surface 61b of the blade 61, the flow of air that has peeled off from the surface of the blade suction surface 61b is reattached by a second convex Thus, unlike the conventional blade 61X shown in FIG. 5, a vortex does not occur at the rear end of the blade 61 on the blade rear surface 61b in the rotational direction, and turbulence can be prevented.
Thereby, the reduction of the substantial negative pressure surface area of the blade back surface 61b of the blade 61 due to separation can be reduced, the static pressure value can be increased, the twist angle can be made smaller than that of the conventional blade 61X, and the axial blower can be used. 6, the number of rotations can be reduced, so that low energy consumption and low noise can be realized.

  Further, the thickness of the wing 61 in a direction orthogonal to the imaginary line L connecting both ends of the wing 61 in the width direction with respect to the width dimension W of the wing 61 is determined by the position of the concave portion between the first convex portion and the second convex portion. In this case, the thickness at the position of the first convex portion is thinner (T1 / W> T2 / W), the thickness at the position of the second convex portion is thicker (T2 / W> T3 / W), and 4 to 15% By forming (T2 / W), it is possible to prevent the air flow on both surfaces of the blade 61 from becoming turbulent.

The wings 61 can be manufactured to have the same cross-sectional shape.
Accordingly, the blade 61 can be easily manufactured by a pultrusion molding method (FRP) or an extrusion molding method (aluminum (including aluminum alloys; the same applies in the present specification)). 6 can be realized at low cost.

In the pultrusion molding method (made of FRP), a reinforcing fiber base mainly composed of glass fiber roving or the like is passed through a resin tank (a tank storing a thermosetting resin such as a liquid unsaturated polyester, epoxy resin, or phenol resin). After performing the impregnation step, then squeeze and defoam the excess resin, introduce it into the mold, heat it in the mold to cure the thermosetting resin, and pull it out with a drawing device to remove it. This is a method for obtaining a molded article formed in the shape of.
Since the molded article is continuously formed endlessly and pulled out, a product can be manufactured by cutting the molded article to an appropriate length.

  The FRP blades 61 can be manufactured by a method other than the pultrusion molding method, for example, a hand lay-up method (in the case of small-quantity production of other products), a spray-up method, or the like.

The extrusion molding method (made of aluminum) is a method of obtaining a molded article formed into a predetermined shape by applying pressure to a die (die) and passing through and extruding a die hole.
Since the molded product is continuously extruded and formed endlessly, the product can be manufactured by cutting the molded product to an appropriate length.

  The aluminum wings 61 can be manufactured by a method other than the extrusion molding method, for example, by using a die casting method.

  Further, by making the wing 61 made of FRP or aluminum, it is possible to obtain a wing that is lightweight and has high strength.

The inside of the blade 61 can be formed in a hollow shape by manufacturing the blade 61 by a pultrusion molding method (made of FRP) or an extrusion molding method (made of aluminum (including an aluminum alloy)). In this case, in addition to the purpose of reinforcement, ribs and thick portions can be formed as necessary to support and fix the shaft member and the end plate 62 extending radially from the boss member 60a.
Thus, the weight of the blades 61 can be reduced, so that low energy consumption of the axial blower 6 can be realized.

The surface of the wing 61 can be coated with a wear-resistant material.
As the wear-resistant material to be coated, in the case of the FRP blade 61, for example, a gel coat material containing white alundum (WA (Al ₂ O ₃ )) and green carborundum (GC (SiC)) is preferably used. Can be used.
Thereby, wear resistance (corrosion resistance) can be improved, and durability can be improved.

  As described above, the cooling tower provided with the axial blower of the present invention has been described based on the embodiment, but the present invention is not limited to the configuration described in the above embodiment, but within a scope that does not depart from the gist thereof. The configuration can be appropriately changed.

  The cooling tower provided with the axial blower of the present invention has a characteristic that the reduction of the substantial suction surface area on the back surface of the blade due to separation can be reduced and the static pressure value can be increased. It can be suitably used for a cooling tower provided with an axial blower.

DESCRIPTION OF SYMBOLS 1 Cooling tower 2 Filling material 20 Plate material 3 Air seal material 4 Water supply tank 5 Drainage tank 6 Axial blower (suction fan)
Reference Signs List 60 rotation axis 60a boss member 61 blade 61a blade front 61b blade back 62 end plate

Claims (7)

In a cooling tower provided with an axial blower configured by arranging a plurality of blades on the suction side on the back side of the blade in a convex shape, the convex shape of the blade back side on the suction side of the blade is provided. The first convex portion is 65 to 85% at a position 20 to 45% of the width of the wing from the tip in the rotation direction of the wing with reference to an imaginary line connecting both ends of the wing in the width direction with respect to the width of the wing. And a concave portion is formed between the first convex portion and the second convex portion, and an imaginary line connecting both ends of the blade in the width direction with respect to the width of the blade. An axial flow blower, wherein the thickness of the blades in the direction orthogonal to each other is formed to be 6 to 20% at the position of the first protrusion and 2 to 10% at the position of the second protrusion. With cooling tower.   The thickness of the wing in a direction orthogonal to an imaginary line connecting both ends in the width direction of the wing with respect to the width dimension of the wing is the first protrusion at the position of the recess between the first protrusion and the second protrusion. The cooling tower provided with an axial blower according to claim 1, wherein the cooling tower is formed to be thinner than the thickness at the position of the portion, thicker than the thickness at the position of the second convex portion, and 4 to 15%. .   The cooling tower provided with an axial blower according to claim 1 or 2, wherein the blades have the same cross-sectional shape.   4. The cooling tower according to claim 1, wherein the blade is made of FRP.   4. The cooling tower according to claim 1, wherein the blade is made of aluminum.   The cooling tower according to claim 1, 2, 3, 4, or 5, wherein the blade is formed in a hollow shape.   The cooling tower according to claim 1, 2, 3, 4, 5, or 6, wherein the blade has a surface coated with a wear-resistant material.

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