# Patent

## Title
Blower capable of reducing secondary flow

## Abstract

A blower capable of reducing secondary flow comprises a frame and a wheel blade part. The wheel blade part is mounted in the frame. The wheel blade part is composed of a hub and a plurality of blades surrounding the hub. The frame is composed of a base and an upper lid plate with a projection part being provided at inner side of the base. The projection part corresponds to the blades on the wheel blade part. A first guide part and a second guide part are provided at an air passage of the base near an opening thereof. The secondary flow produced in the blower can be reduced by way of the projection at the inner side of the base and the first and second guide parts at the air passage of the base near the opening thereof.

## Background
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention is related to a blower capable of reducing secondary flow and particularly to a frame device used in a blower.
2. Brief Description of the Related Art
Referring to FIGS. 1 and 2, the conventional blower 1 includes a frame 11 and a wheel blade part 12 disposed in the frame 11. The frame 11 is composed of a base 111 and an upper lid plate 112. The wheel blade part 12 is composed of a hub 121 and a plurality of blades 122 surrounding the hub 121.
Referring to FIG. 3, a distance results between the lower edges 122a of the blade 122 and the inner side 111a of the base 111 to produce a secondary flow at a space formed by the distance. The secondary flow can result in loud noise and block the airflow so as to reduce the overall air pressure and amount of the airflow.
Although the base 111 of the conventional blower 1 can be lifted the inner side 111a thereof to decrease the distance to the lower edges 122a of the blades 122 in order to reduce occurring the secondary flow, the inner space of the base 111 becomes smaller too to lead reduction of the overall air pressure and the amount of airflow.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a blower capable of reducing secondary flow.



BRIEF DESCRIPTION OF THE DRAWINGS
The detail structure, the applied principle, the function and the effectiveness of the present invention can be more fully understood with reference to the following description and accompanying drawings, in which:
FIG. 1 is an exploded perspective view of a conventional blower;
FIG. 2 is an assembled perspective view of the conventional blower;
FIG. 3 is a sectional view along line 3-3 shown in FIG. 2;
FIG. 4 is an exploded perspective view of the blower according to the present invention;
FIG. 5 is an assembled perspective view of the blower according to the present invention; and
FIG. 6 is a sectional view along line 6-6 according to the present invention.



DETAILED DESCRIPTION OF THE INVENTION
Referring to FIGS. 4 and 5, a blower 2 according to the present invention comprises a frame 21 and a wheel blade part 22. The wheel blade part 22 is composed of a hub 221 and a plurality of blades 222 surrounding the hub 221. The frame 21 is composed of a base 211 and an lid plate 212 and base 211 has a circular sham, periphery wall 211 and a base part at 211a. The base part 211a is disposed at the bottom of the periphery wall 211 and an axial barrel extends from the base part 211a to fit with the hub 221 such that an elevation space is formed between the wheel blade part 22 and the base part 211a. An annular projection part 211b is disposed at the base part 211a surrounding the axial barrel to extend toward the elevational space such that a clearance is formed between the annular projection the lower edges 222a of the blades 222 on the wheel blade part 22.
Referring to FIG. 6, the projection part 211b reduces the distance between the lower edges 222a and the inner side 211a to the least extent and partitions the distance. When the wheel blade part 22 rotates, the airflow introduced by the blades 222 can be restricted by the projecting part 211b to allow the airflow being not easy to constitute secondary flow in the elevational space between the wheel blade part 222 and base part 211a of the base 211.
Referring to FIGS. 3 to 6, the projection part 211b at the inner side of the base 211 can overcome the deficiency of excessive large distance between the lower edges 122a of the blades 122 producing the secondary flow. In addition, the air pressure and airflow are increased at the opening 211d provided at the base 211.
Besides, a first guide part 211e and a second guide part 211f can be provided at two lateral sides of the opening 211d of the periphery wall of the base 211. The respective guide part 211e. 211f has a shape similar to a wedge to guide the air so as to reduce noise created by the wheel blade part 22 of the blower 2 during running.
While the invention has been described with referencing to the preferred embodiment thereof, it is to be understood that modifications or variations may be easily made without departing from the spirit of this invention, which is defined by the appended claims.

## Claims

1. A blower capable of reducing secondary flow comprising:
a frame, providing a base with a periphery wall and an upper lid plate covering the base, an axial barrel extending from the base and having an opening at the periphery wall; and
a wheel blade part, being received in the frame, providing a hub to fit with the axial barrel and having a plurality of blades surrounding the hub such that an elevational space is formed between the base and the fan blade part;
characterized in that the inner side of the periphery wall next to two opposite sides of the opening is attached to a first guide part and a second guide part respectively and the first guide part provides a long-curved-wedge shape and the second guide part provides short-curved-wedge shape for reducing noise during the wheel blade part running.