U.S. patent application number 09/846534 was filed with the patent office on 2002-09-19 for induced-draft fan for hot air gun/air dryer.
Invention is credited to Cheng, Chuan-Hsin.
Application Number | 20020131863 09/846534 |
Document ID | / |
Family ID | 21682037 |
Filed Date | 2002-09-19 |
United States Patent
Application |
20020131863 |
Kind Code |
A1 |
Cheng, Chuan-Hsin |
September 19, 2002 |
Induced-draft fan for hot air gun/air dryer
Abstract
An induced-draft fan for hot air gun/air dryer includes a
casing, the casing having a motor mount and a plurality of spiral
wing guides radially arranged around the fan mount, a fan blade
unit, and a fan motor mounted in the motor mount and controlled to
rotate the fan blade unit, the fan blade unit having a
semispherical body coupled to the fan motor, and a plurality of
blades radially spirally arranged around the semispherical
peripheral surface of the semispherical body, the blades being
curved in direction reversed to the spiral wing guides, each blade
having a top wind cut face and a bottom side edge disposed in flush
with the bottom edge of the semispherical peripheral surface of the
semispherical body.
Inventors: |
Cheng, Chuan-Hsin;
(San-chung City, TW) |
Correspondence
Address: |
Keith Kline
PRO-TECHTOR INTERNATIONAL SERVICES
20775 Norada Court
Saratoga
CA
95070-3018
US
|
Family ID: |
21682037 |
Appl. No.: |
09/846534 |
Filed: |
April 30, 2001 |
Current U.S.
Class: |
415/219.1 |
Current CPC
Class: |
F04D 19/002 20130101;
F04D 29/544 20130101 |
Class at
Publication: |
415/219.1 |
International
Class: |
F04D 029/38 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 14, 2001 |
TW |
90203800 |
Claims
What the invention claimed is:
1. An induced-draft fan for hot air gun/air dryer comprising a
casing, a fan motor mounted in said casing, said fan motor
comprising a motor shaft, and a fan blade unit coupled to said
motor shaft of said fan motor and driven to induce currents of air
upon operation of said fan motor, wherein said fan blade unit
comprises a semispherical body coupled to said motor shaft of said
fan motor, said semispherical body having a semispherical
peripheral surface and a bottom edge, and a plurality of blades
radially spirally arranged around the semispherical peripheral
surface of said semispherical body, said blades each having a top
wind cut face and a bottom side edge disposed in flush with the
bottom edge of the semispherical peripheral surface of said
semispherical body.
2. The induced-draft fan of claim 1 wherein said casing comprises a
cylindrical peripheral wall, a motor mount suspended inside said
cylindrical peripheral wall and adapted to hold said fan motor, and
a plurality of wing guides radially connected between said motor
mount and said cylindrical peripheral wall, said wing guides being
spirally curved in direction reversed to said blades of said fan
blade unit.
Description
BACKGROUND OF THE INVENTION
[0001] The present invention relates to hot air guns/air dryers
and, more specifically, to an induced-draft fan for hot air gun/air
dryer.
[0002] A conventional fan for hot air gun/air dryer, as shown in
FIGS. 1 and 2, is generally comprised of a casing B, a fan motor A
mounted in the casing B at one side, and a fan blade unit C coupled
to the output shaft of the fan motor A. When starting the fan motor
A, the fan blade unit C is rotated to induced currents of air. This
structure of fan is still not satisfactory in function, and has
numerous drawbacks as outlined hereinafter.
[0003] 1. The fan blade unit C has a cylindrical profile with a
smooth periphery. When rotating the fan blade unit C to induce
currents of air, currents of air directly impact the smooth
peripheral surface of the fan blade unit C, thereby producing much
wind resistance that reduces the induced volume of currents of
air
[0004] 2. Because the blades D of the fan blade unit C are radially
extended from the smooth peripheral surface of the cylindrical body
of the fan blade unit C, the fan blade unit C occupies much
installation space. Increasing the size of the blades D in order to
increase the capacity of the fan blade unit C simultaneously
increase the dimensions of the fan blade unit C. In the limited
space of the hot air gun/air dryer, the size of the fan blade unit
C is limited.
[0005] 3. Because the body of the fan blade unit C has a
cylindrical shape, much wind resistance is produced during rotary
motion of the fan blade unit C, resulting in back turbulent flow of
air and resonance noises.
SUMMARY OF THE INVENTION
[0006] It is one object of the present invention to provide an
induced-draft fan for hot air gun/air dryer, which produces less
wind resistance and turbulent flow of air. It is another object of
the present invention to provide an induced-draft fan or hot air
gun/air dryer, which induces a big volume of wind when operated. It
is still another object of the present invention to provide an
induced-draft fan for hot air gun/air dryer, which produces little
noise during operation. According to one aspect of the present
invention, the fan blade unit comprises a semispherical body, and a
plurality of blades spirally radially arranged around the
semispherical peripheral surface of the semispherical body and
turned with the semispherical body to induce currents of air
without causing much wind resistance. According to another aspect
of the present invention, the casing of the induced-draft fan
comprises a plurality of spiral wing guides radially arranged
around the motor mount, which supports the fan motor. The spiral
wing guides are curved in direction reversed to the radially
spirally arranged blades of the fan blade unit, for causing induced
currents of air to form an eddy blow of air.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] FIG. 1 is an exploded view of a fan for hot air gun/air
dryer according to the prior art.
[0008] FIG. 2 illustrates the path of induced currents of air
according to the prior art.
[0009] FIG. 3 is an exploded view of an induced-draft fan for hot
air gun/air dryer according to the present invention.
[0010] FIG. 4 illustrates the path of induced currents of air
according to the present invention.
[0011] FIG. 5 is a side view in an enlarged scale of the fan blade
unit according to the present invention.
[0012] FIG. 6 is an applied view of the present invention, showing
the induced-draft fan installed in a hot air gun.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0013] Referring to FIGS. 3 and 4, an induced-draft fan for hot air
gun/air dryer in accordance with the present invention is shown
comprised of a casing 1, a fan motor 2, and a fan blade unit 3. The
casing 1 comprises a motor mount 11 on the inside at the center,
and a plurality of wind guides 12 radially connected between the
periphery of the motor mount 111 and the inside wall of the casing
1. The fan motor 2 is mounted in the motor mount 11 inside the
casing 1. The fan blade unit 3 is coupled to the motor shaft 21 of
the fan motor 2.
[0014] Referring to FIGS. S and 6 and FIGS. 3 and 4 again, the fan
blade unit 3 comprises a body 31 and a plurality of blades 32. The
body 31 has a semispherical profile and a center-mounting rod 311
disposed on the inside. The blades 32 are radially spirally
arranged around the semispherical peripheral surface of the body
31, each having a top wind cut face 321 and a bottom side edge
disposed in flush with the bottom edge of the semispherical
peripheral surface of the body 31. After installation of the fan
motor 2 in the motor mount 11 inside the casing 1, the fan blade
unit 3 is inserted into the casing 1 to force the center-mounting
rod 311 of the semispherical body 31 of the fan blade unit 3 into
engagement with the motor shaft 21 of the fan motor 2. When
starting the fan motor 2, induced currents of air are smoothly
guided forwards through the semispherical peripheral surface of the
semispherical body 31. Because the blades 32 are radially spirally
arranged around the semispherical peripheral surface of the
semispherical body 31, less wind resistance and turbulent flow of
air is produced during the operation of the induced-draft fan.
Because the wind cut face 321 cuts through the induced currents of
air at a small angle, low noise is produced when currents of air
are induced and guided out of the hot air gun 4 in which the
induced-draft fan is installed.
[0015] Referring to FIG. 5 again, the wing guides 12 are spirally
curved in direction reversed to the curving direction of the blades
32 of the fan blade unit 3. When rotating the fan blade unit 3 to
induce currents of air, the spirally curved wing guides 12 guide
the induced currents of air forwards, forming an eddy flow of
air.
[0016] A prototype of induced-draft fan has been constructed with
the features of FIGS. 3 and 4. The induced-draft fan functions
smoothly to provide all of the features discussed earlier.
[0017] Although a particular embodiment of the invention has been
described in detail for purposes of illustration, various
modifications and enhancements may be made without departing from
the spirit and scope of the invention. Accordingly, the invention
is not to be limited except as by the appended claims.
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