ADJUSTABLE IMPELLER FOR AXIAL FLOW FAN

Abstract

A fan assembly has a plurality of blades received on a rotatable hub and held on the hub with a retainment mechanism. The hub has a plurality of hub stations located thereon, each hub station having a plurality of radially extending hub cogs and a hub indexing mark. Each blade in the fan assembly has a blade end having a plurality of radially extending blade cogs configured to interface with the hub cogs. The blade end also has a blade positioning mark adjacent one of the blade cogs. The blade may be rotated with respect to the hub to a plurality of different orientations and still have the blade cogs mesh with the hub cogs.

Description

BACKGROUND OF THE INVENTION

Field of Invention

This invention relates to axial flow fans in ventilation systems for animal buildings, and more particularly to a fan with a hub that permits the angle of an impeller blade to be adjusted.

Description of Related Art

Achieving optimal performance from animals raised in commercial animal house buildings (such as a poultry house) depends in part on providing ventilation as correctly and efficiently as possible. Proper ventilation improves overall over air quality, air temperature, and energy usage. Improper ventilation levels can lead to incorrect moisture levels, unsuitable temperatures, and poor air quality.

Ventilation fans are often used as part of the ventilation system for animal houses. Many factors affect the amount of air a fan can move. The power of the motor, size and shape (aerodynamics) of the blades, the material of which the blades are made, the RPM at which the blades spin, and the blade pitch are all factors that contribute to airflow and the performance of the fan.

Other factors being equal, the steeper the blade pitch, the more air the fan will move. At present, the pitch angle of some agriculture fan impellers can't be changed. Others require a time intensive and imprecise method of loosening and repositioning of the fan blade. Some others can be changed, but an additional angle block component must be added. Because of the part and assembly deviations, problems such as impeller vibration often result when trying to change the pitch angle of the fan.

Accordingly, a need exists for a ventilation fan assembly that allows for better adjustment of the fan blades.

BRIEF SUMMARY

In one aspect, the invention is directed to a fan assembly having an impeller with a plurality of blades configured to move air as the impeller is rotated each blade is received on a rotatable hub and held on the hub with a retainment mechanism. The hub has an outward surface with a plurality of hub stations located thereon, each hub station having a plurality of radially extending hub cogs. The hub has a hub indexing mark located adjacent one of the hub cogs. Each blade in the fan assembly has a blade end having a plurality of radially extending blade cogs configured to interface with the hub cogs. The blade end also has a blade positioning mark adjacent one of the blade cogs. The blade cogs and hub cogs are configured so that when the blade is brought into position such that the blade end mates with one of the plurality of hub stations, the hub cogs mesh with the blade cogs. The blade may be rotated with respect to the hub to a plurality of different orientations and still have the blade cogs mesh with the hub cogs.

These and other features and advantages of this invention are described in, or are apparent from, the following detailed description of various exemplary embodiments of the systems and methods according to this invention.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

To easily identify the discussion of any particular element or act, the most significant digit or digits in a reference number refer to the figure number in which that element is first introduced.

FIG. 1 illustrates is a perspective view of a fan assembly in accordance with one embodiment of the invention;

FIG. 2 illustrates an exploded perspective view of the fan assembly of FIG. 1;

FIG. 3 illustrates a perspective view of a hub of the fan assembly of FIG. 1;

FIG. 4 illustrates a perspective view of a portion of the impeller blade of the fan assembly of FIG. 1; and

FIG. 5 illustrates an exploded perspective view of the hub and impeller blades of the fan assembly of FIG. 1.

Corresponding reference characters indicate corresponding parts throughout the views of the drawings.

DETAILED DESCRIPTION

The invention will now be described in the following detailed description with reference to the drawings, wherein preferred embodiments are described in detail to enable practice of the invention. Although the invention is described with reference to these specific preferred embodiments, it will be understood that the invention is not limited to these preferred embodiments. But to the contrary, the invention includes numerous alternatives, modifications and equivalents as will become apparent from consideration of the following detailed description.

FIG. 1 illustrates a fan assembly 102 such as one to be installed in a sidewall of an animal house (not shown). As is known in the art, fan assemblies 102 are used as part of an overall ventilation system for the animal houses to enable adequate and efficient airflow and circulation within the animal house. The fan assembly 102 comprises an impeller 104 attached to a suitable motive force (not shown) which turns impeller 104. The motive force of the fan assembly 102 may be of any suitable design known to one skilled in the art and need not be discussed further herein. The impeller 104 has a plurality of blades 106 configured to move air as the impeller 104 is rotated by the motive force. In the illustrated embodiment, the fan assembly 102 has three blades 106, however, may have other number of blades 106, such as four, five, or six, without departing from the scope of the invention.

As best seen in FIG. 2, each blade 106 is received on a rotatable hub 202 and held on the hub with a retainment mechanism 204. In the illustrated embodiment, the retainment mechanism 204 includes a front cover 206 and a rear cover 208 held together with a plurality of bolts 210 and nuts 212 that mechanically secure the blades 106 on the hub 202. However, other means may be used to hold the blades 106 on the hub 202 may be used using sound engineering judgement without departing from the scope of the invention.

Turning also now to FIG. 3, the hub 202 has an outward surface 302 with a plurality of hub stations 304 located thereon. The hub 202 has at least one hub station 304 for each of the blades 106 on the fan assembly 102. In the illustrated embodiment, the hub 202 has six hub stations 304 but only three of the hub stations 304 have a blade 106 mounted to it. Thus, the hub 202 in the illustrated embodiment could also be used with a fan assembly 102 that has six blades 106. Each hub station 304 has a series of radially extending teeth or hub cogs 306. The purpose of the hub cogs 306 will be explained below. A hub indexing mark 308 is located next to one of the hub cogs 306.

As best seen in FIG. 4, each blade 106 has a blade end 402. The blade end 402 has a plurality of radially extending teeth or blade cogs 404 configured to interface with the hub cogs 304. When the blade 106 is brought into position with the hub 202 such that the blade end 402 mates with the hub station 304 and held together with the retainment mechanism 204, the hub cogs 306 interact with the blade cogs 404 so that the blade 106 rotates with the hub 202. The blade 106 may be rotated with respect to the hub 202 to a plurality of different orientations and still have the blade cogs 404 mesh with the hub cogs 306. The blade end 402 has a blade positioning mark 406.

Turning also now to FIG. 5, when the blade 106 is brought against the hub 202 with the blade positioning mark 406 aligned with the hub indexing mark 308, the blade 106 has a blade pitch angle that is a benchmark blade angle. The blade 106 can be rotated with respect to the hub 202 in a first direction, for example a clockwise direction, to decrease the blade angle of the blade 106 relative to the benchmark blade angle. The blade 106 can be rotated with respect to the hub 202 in a second direction opposite the first direction to increase the blade angle of the blade 106 relative the benchmark blade angle. Accordingly, the blade angle of the blade 106 can be selected or changed by the operator to any one of a plurality of different blade angles to meet the ventilation needs of the animal house. To change the blade angle, one must simply operate the retainment mechanism 204 so that the blade 106 is no longer held on the hub 202, rotate the blade end 402 relative the hub station 304 using the blade positioning mark 406 and hub indexing mark 308 as guides to achieve a desired blade angle, and then operate the retainment mechanism 204 so that the blade 106 is once again firmly held on the hub 202.

The foregoing has broadly outlined some of the more pertinent aspects and features of the present invention. These should be construed to be merely illustrative of some of the more prominent features and applications of the invention. Other beneficial results can be obtained by applying the disclosed information in a different manner or by modifying the disclosed embodiments. Accordingly, other aspects and a more comprehensive understanding of the invention may be obtained by referring to the detailed description of the exemplary embodiments taken in conjunction with the accompanying drawings.

Claims

1. A fan assembly having an impeller with a plurality of blades configured to move air as the impeller is rotated each blade is received on a rotatable hub and held on the hub with a retainment mechanism, wherein the hub has an outward surface with a plurality of hub stations located thereon, each hub station having a plurality of radially extending hub cogs, and a hub indexing mark located adjacent one of the hub cogs, wherein each blade has a blade end having a plurality of radially extending blade cogs configured to interface with the hub cogs and a blade positioning mark adjacent one of the blade cogs, the blade cogs and hub cogs configured so that when the blade is brought into position such that the blade end mates with one of the plurality of hub stations, the hub cogs mesh with the blade cogs, and wherein the blade may be rotated with respect to the hub to a plurality of different orientations and still have the blade cogs mesh with the hub cogs.

2. The fan assembly of claim 1 wherein the retainment mechanism includes a front cover and a rear cover held together with a plurality of bolts and nuts that mechanically secure the blades on the hub.

3. The fan assembly of claim 1 wherein the hub has at least one hub station for each of the blades on the fan assembly.

4. The fan assembly of claim 1 when the blade is brought against the hub with the blade positioning mark aligned with the hub indexing mark, the blade has a blade pitch angle that is a benchmark blade angle.

5. The fan assembly of claim 4 wherein the blade can be rotated with respect to the hub in a first direction to decrease the blade angle of the blade relative to the benchmark blade angle, and the blade can be rotated with respect to the hub in a second direction opposite the first direction to increase the blade angle of the blade relative the benchmark blade angle such that the blade angle of the blade can be selected or changed by the operator to any one of a plurality of different blade angles