WO2010122594A1

WO2010122594A1 - Apparatus for the construction of fan wheels of the double suction type

Info

Publication number: WO2010122594A1
Application number: PCT/IT2010/000195
Authority: WO
Inventors: Franco Collu
Original assignee: Nicotra Gebhardt S.P.A.
Priority date: 2009-04-21
Filing date: 2010-04-19
Publication date: 2010-10-28
Also published as: IT1393947B1; CN102395797B; EP2422095B1; EP2422095A1; ITMI20090666A1; CN102395797A

Abstract

The apparatus comprises an assembly mandrel formed (15) of two cylindrical components (16, 17) displaceable one relative to the other and operable to rotate about a common axis, and a pair of circular plates (18, 19) slidably mounted on the ends of the assembly mandrel. The assembly mandrel carries seats adapted for supporting and holding in position the end rings and the central disk. The cylindrical components of the assembly mandrel are provided with retaining means (20), arranged on the lateral surface thereof, for temporary holding in position the blades of the fan wheel. Rolling (25) and flanging (26) devices are mounted near the seats of the end rings and of the central disk on the assembly mandrel. The cylindrical components of the assembly mandrel are axially displaceable one relative to the other between a spaced apart position for mounting the end rings and the central disk and an approached position for carrying out the rolling and flanging operations of the end rings and the central disk onto the blade ends.

Description

APPARATUSFORTHE CONSTRUCTIONOF FANWHEELSOF THEDOUBLE SUCTIONTYPE

DESCRgTION

Technical field of the invention

The present invention generally relates to the technical field of industrial fans, and in particular concerns an apparatus for the construction of fan wheels of the double suction type.

Background art

According to a conventional embodiment, a fan wheel of the type mentioned above is essentially formed by two arrays of inclined blades arranged on a cylindrical surface, a pair of blade restraining end rings, and at least one central disk supporting the blades and carrying the fan wheel hub.

The fan blades are fastened through a positive locking and non- positive connection to the central disk and to the end rings by shaping the blade ends and securing them with a rolling and flanging operation into suitable grooves or slots of the central disk and of the end rings. The construction method of fan wheels of the type mentioned previously, at present, requires many operations to be performed which, on the one side, concur to complicate the production cycle, and on the other increase the costs of the finished product. Essentially, the known construction method consists of the separate assembling of the two arrays of blades and the subsequent joining of the preassembled array of blades to form a unitary double suction fan wheel.

This construction method has the drawback of being relatively long, complicated and expensive to perform; furthermore, it does not lend itself easily to the production of a fan wheel having high structural stiffness.

This being the background art, an object of the present invention is to provide an apparatus for the construction of fan wheels of the double suction type as previously described which allows the blade ends to be fastened to the central disk and to the end rings in a single assembling operation, thus without requiring the separate assembling of the two arrays of blades and the subsequent joining of the array of blades to form the fan wheel.

Another object of the present invention is to provide an apparatus allowing the mass production of fan wheels as mentioned above, requiring only a minimum number of assembly operations and permitting fan wheels, also large in size and having high structural stiffness, to be constructed with only a minimum use of labour and in the most inexpensive and simple manner as possible. A further object of the present invention is to achieve a particularly suitable positive locking and non-positive connection of the fan blades to the central disk and to the end rings, which can prevent deformation of the fan wheel even at high peripheral speeds. Disclosure of the invention

In order to achieve the above-indicated objects, according to the invention there is provided an apparatus for the construction of fan wheels of the double suction type, comprising a plurality of inclined blades arranged on a cylindrical surface, a pair of blade restraining end rings and at least one central disk supporting the blades and carrying the fan wheel hub, characterised in that said apparatus comprises an assembly mandrel formed of two cylindrical components displaceable one relative to the other and operable to rotate about a common axis, and a pair of circular plates slidably mounted on the ends of the assembly mandrel, said assembly mandrel carrying seats adapted for supporting and holding in position the end rings and the central disk, and said cylindrical components of the assembly mandrel being provided with retaining means, arranged on the lateral surface thereof, for temporary holding in position the blades of the fan wheel during the construction operations thereof, and in that rolling and flanging devices are mounted near said seats of the end rings and the central disk on the assembly mandrel for rolling and flanging said end rings and said central disk onto the blade ends, and in that said cylindrical components of the assembly mandrel are axially displaceable one relative to the other, upon action of said circular plates, between a spaced apart position for mounting said end rings and said central disk and an approached position for carrying out the rolling and flanging operations of said end rings and said central disk onto the blade ends, and in that said cylindrical components are provided on their facing base surfaces with mating coupling elements adapted to establish a connection between the cylindrical components in their approached position, in order to permit an exactly congruent rotation thereof during the rolling and flanging operations.

Brief description of drawings

The invention will be still better understood from the following description of a preferred, although non limitative, embodiment thereof, partially and schematically shown in the accompanying drawings, wherein:

- Figure 1 is a perspective view of the overall structure of a fan wheel made with an apparatus according to the invention. - Figure 2 is a front elevational view of the fan wheel of Figure 1.

- Figure 3 is a sectional view of the fan wheel taken along line HI-III of Figure 2.

- Figure 4 is an enlarged view of the detail A of Figure 3.

- Figure 5 is an enlarged view of the detail A of Figure 3 showing the blades of the fan wheel during the phase of positioning the same on the central disk of the fan wheel.

- Figure 6 is an enlarged view of the detail B of Figure 3.

- Figure 7 is an enlarged view of the detail B of Figure 3 showing the blades of the fan wheel during the phase of positioning the same on the end rings of the fan wheel.

- Figure 8 is a perspective partial view of an apparatus according to the invention for the construction of the fan wheel of Figure 1. - Figure 9 is a longitudinal cross-sectional view of the apparatus of Figure 8 shown in the configuration at the beginning of the production cycle of the fan wheel of Figure 1.

- Figure 10 is a longitudinal cross-sectional view of the apparatus of Figure 8 shown at the end of the phase of approaching of the cylindrical components of the assembly mandrel.

- Figure 11 is an enlarged view of the detail A of Figure 10 showing the positioning of a first end of the blades into the peripheral edge of the central disk. - Figure 12 is an enlarged view of the detail B of Figure 10 showing the positioning of a second end of the blades into the end rings.

- Figure 13 is a longitudinal cross-sectional view of the apparatus of Figure 8 shown during the first phase of the operation of rolling the end rings and the central disk on the blade ends. - Figure 14 is an enlarged view of the detail A of Figure 13 showing the first phase of the operation of rolling the central disk on a first end of the blades.

- Figure 15 is an enlarged view of the detail B of Figure 13 showing the first phase of the operation of rolling the end rings on a second end of the blades.

- Figure 16 is a longitudinal cross-sectional view of the apparatus of Figure 8 showing a second phase of the operation of rolling the end rings and the central disk on the blade ends. - Figure 17 is an enlarged view of the detail A of Figure 16 showing the second phase of the operation of rolling the central disk on a first end of the blades.

- Figure 18 is an enlarged view of the detail B of Figure 16 showing the second phase of the operation of rolling the end rings on a second end of the blades.

- Figure 19 is a longitudinal cross-sectional view of the apparatus of Figure 8 shown during the operation of flanging the end rings and the central disk on the blade ends. - Figure 20 is an enlarged view of the detail A of Figure 19 showing the operation of flanging the central disk on a first end of the blades.

- Figure 21 is an enlarged view of the detail B of Figure 19 showing the operation of flanging the end rings on a second end of the blades.

Description of a preferred embodiment of the invention

With reference to Figs. 1 to 7 of the drawings, the proposed embodiment of the fan wheel of the double suction type consists essentially of a plurality of blades 10 of suitable shape having at their axial end bases or feet 11 which are adapted to be arranged along a circumference and are in contact one with the other for determining the desired pitch between the blades 10. These blades, together with the relevant feet, can be obtained in a known manner by sheet blanking.

The structure of the fan wheel is formed of two groups or arrays 12 of blades, arranged side by side, and each consisting of a predetermined number of blades 10 arranged to form a cylindrical surface. This structure is made self-supporting by means of a pair of end rings 13, each of which being substantially U-shaped (Figure 7) in cross-section so as to form a hollow section for receiving the blade feet 11, with one side of the said U- shaped hollow section of the end rings being bent over the blade feet 11 to constrain the same (Figure 6). The structure of the fan wheel is then completed by a central disk 14 formed of a pair of half-disks 14A and 14B, opposite each other and joined together, carrying the hub of the fan wheel and having a peripheral edge forming in cross-section a substantially U- shaped hollow section (Figure 5), similar to that of the end rings 13, for receiving the blade feet 11 opposite to those constrained by the end rings 13, one side of said U-shaped hollow section of the peripheral edge of the central disk being bent over said blade feet 11 to constrain the same (Figure

4). For the construction of a fan wheel of the illustrated type there is provided, according to the invention, an apparatus whose main components are shown in Figs. 8 and 9 of the drawings. Essentially, this apparatus consists of an assembly mandrel 15 formed of two substantially symmetrical cylindrical components or drums 16 and 17, which are displaceable one relative to the other and are operable to rotate about a common axis, and a pair of circular plates 18 and 19 which are slidably mounted on the opposite ends of the assembly mandrel 15. Drums 16 and 17 are provided with retaining means, e.g. of elastic or magnetic type, arranged on their lateral surface, for temporary holding in position the blades 10 of the fan wheel during the construction operations thereof. Drums 16 and 17 are furthermore provided with mating coupling elements 21 and 22 which are arranged on their facing base surfaces and are adapted to establish a connection between the said drums when these are in an approached position, in order to permit an exactly congruent rotation thereof during the rolling and flanging operations of the fan wheel, as will be described in more detail in the following section in connection with the various operations for the construction of the fan wheel. The assembly mandrel 15 furthermore comprises seats 23 and 24 which are adapted for supporting and holding in position the end rings 13 and the central disk 14, respectively. Proximate said seats on the end rings and the central disk, the apparatus is provided with rolling and flanging devices 25 and 26, respectively, of known type, e.g. consisting of pins and arms carrying rolling and flanging wheels, respectively, which are capable of being lowered, by action of one or more hydraulic actuators, on the end rings 13 and the central disk 14 to bend the edges thereof on the feet 11 of the blades 10.

Before the beginning of the construction cycle of the fan wheel, an operator provides for the assembly of the central disk 14 and the connection of the hub thereto. Thereafter, the operator mounts the central disk 14 on the assembly mandrel 15 and positions it in the corresponding seat 24. The operator then positions the end rings 13 in the corresponding seats 23 of the circular plates 18 and 19 and places the blades 10 on the drums 16 and 17. Finally, the side plates 18 and 19 are mounted on the ends of the assembly mandrel 15 for holding in position the end rings 13. The apparatus is thus ready to begin the construction cycle of the fan wheel which will be described in the following section with reference to Figs. 10 to 21 of the drawings.

The construction cycle begins with the side plates 18 and 19 being moved towards each other into an approached position, wherein the drums

16 and 17 are arranged side by side and the coupling elements 21 and 22 establish a functional connection between said drums 16 and 17. When the drums 16 and 17 are in the approached position, the feet 1 ϊ of the blades 10 are placed inside the U-shaped hollow section of the end rings 13 and of the peripheral edge of the central disk 14 (Figs. 11 and 12).

Thereafter, the drums 16 and 17 are placed in rotation and the rolling devices 25 are positioned on the end rings 13 and on the central disk 14, in order to bend their sides over the feet 11 of the blades 10. The rolling operation generally comprises two phases. In a first phase of the roiling operation, the edges of the end rings 13 and of the central disk 14 are bent inwardly (Figs. 13 to 15). In a second phase of the rolling operation, the edges of the end rings 13 and of the central disk 14 are bent over the feet 11 of the blades 10 (Figs. 16 to 18). During or after this second phase of the rolling operation, also the flanging devices 16 are positioned on the end rings 13 and on the central diskl4 for pressing the edges thereof against the feet 11 of the blades 10 (Figs. 19 to 21).

The construction cycle of the fan wheel ends with the drums 16 and

17 being moved to a spaced apart position in which the fan wheel can be removed from the assembly mandrel 15. In this position, the operator then mounts the end rings 13 and the central disk 14 and places the blades 10 for the beginning of the construction cycle of another fan wheel.

From the foregoing it is apparent that the apparatus can achieve the proposed objects, and in particular it allows the blade feet to be fastened to the end rings and to the central disk in a single assembly operation.

Obviously, many variants which are apparent to the skilled in the art can be applied to the embodiment as described and shown, without departing from the scope and domain of the appended claims.

Claims

1. Apparatus for the construction of fan wheels of the double suction type, comprising a plurality of inclined blades arranged on a cylindrical surface, a pair of blade restraining end rings and at least one central disk supporting the blades and carrying the fan wheel hub, characterised in that said apparatus comprises an assembly mandrel formed of two cylindrical components displaceable one relative to the other and operable to rotate about a common axis, and a pair of circular plates slidably mounted on the ends of the assembly mandrel, said assembly mandrel carrying seats adapted for supporting and holding in position the end rings and the central disk, and said cylindrical components of the assembly mandrel being provided with retaining means, arranged on the lateral surface thereof, for temporary holding in position the blades of the fan wheel during the construction operations thereof, and in that roiling and flanging devices are mounted near said seats of the end rings and the central disk on the assembly mandrel for rolling and flanging said end rings and said central disk onto the blade ends, and in that said cylindrical components of the assembly mandrel are axially displaceable one relative to the other, upon action of said circular plates, between a spaced apart position for mounting said end rings and said central disk and an approached position for carrying out the rolling and flanging operations of said end rings and said central disk onto the blade ends, and in that said cylindrical components are provided on their facing base surfaces with mating coupling elements adapted to establish a connection between the cylindrical components in their approached position, in order to permit an exactly congruent rotation thereof during the rolling and flanging operations. ,

2. Apparatus according to claim 1, characterised in that the blade retaining means are of resilient or magnetic type.

3. Apparatus according to claim 1, characterised in that the coupling means are arranged symmetrically on the facing base surfaces of the cylindrical components.

4. Apparatus according to claim 1, characterised in that the rolling devices are formed of pins carrying rolling wheels capable of being lowered on the end rings and the central disk to bend the edges thereof on the blade feet.

5. Apparatus according to claim 1, characterised in that the flanging devices are formed of arms carrying flanging wheels capable of being lowered on the end rings and the central disk to join together the edges thereof and the blade feet

6. Apparatus according to claim 1, characterised in that the rolling and flanging devices are operable by means of hydraulic actuators.