Electric resistance heating devices – Heating devices – Radiant heater
Reexamination Certificate
2002-12-16
2004-06-01
Jeffery, John A. (Department: 3742)
Electric resistance heating devices
Heating devices
Radiant heater
C392S426000, C392S376000
Reexamination Certificate
active
06744977
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an electric heater with a heat shield plate for preventing heat heating rays of the heater and introduction of foreign materials into the heater. More particularly, the present invention relates to an electric heater in which a heat shield plate formed with a plurality of through-holes is installed on a curved plate serving as a reflector to prevent overheat of the electric heater and perform a heat shielding function.
2. Description of the Prior Art
As living standards are improved, a heater as a dominant one of room heating apparatuses has been generally changed from a conventional oil heater to an electric heater. It goes without saying that various kinds of electric heaters have been developed as social demands for the heaters are increased.
As well known in the art, a fundamental operating principle of the electric heater is that ambient air is heated with heat generated when an electric current flows through a heating wire which is placed within a specific space and protected by a safety net. Furthermore, additional means for radiating the heat more efficiently from the heating wire are further installed in the electric heater. As a typical example thereof, a type of electric heater in which a reflector manufactured by curving a substantially rectangular metal sheet to a certain extent is installed behind the heating wire has been spread. However, this electric heater hardly obtains an effect of efficient heat radiation. Such a conventional electric heater has a problem in that a sufficient amount of heat cannot be fully transferred up to a desired distance. In fact, in a case where an amount of electric current is increased so as to increase the amount of heat generated from the heater, there is a risk of overheating and fire. However, if the amount of electric current is reduced in consideration of a safety accident due to the increase of the electric current, it is difficult to obtain the sufficient amount of heat to a desired extent.
In order to solve the problems in the conventional electric heater, a radiant electric heater capable of fully heating room air by transferring an adequate amount of heat as far as possible has been developed and disclosed in Korean Laid-Open Utility Model Publication No. 98-61527.
Such a radiant electric heater is configured in such a manner that a spherical reflector is installed behind a heating wire and a portion to which the heating wire is attached is reduced in diameter in a rearward direction so that heat cannot be diffused in all directions and can be concentrated within a narrow range. Therefore, the heat can be transferred as far as possible. Referring to
FIGS. 1 and 2
, the electric heater
10
comprises a heat generating unit
10
including a heating wire, and a supporting unit
20
for supporting the heat generating unit.
First, the supporting unit
20
will be described below. A main circuit for operating and controlling the radiant electric heater
1
is installed within a stand
21
. Further, a power switch
22
for turning electrical power on or off, a temperature control switch
23
for intermittently turning the electrical power off at a predetermined temperature so that the temperature of the heating wire can be kept to be optimal, a power lamp
24
for indicating whether the electrical power is turned on or off, a safety switch
29
for intermittently turning the electrical power off in accordance with whether the electric heater is tilted, a warning lamp
25
for warning a user when the electric heater is excessively tilted, and the like are arranged at the top and bottom of the stand
21
.
Furthermore, the heat generating unit
10
and the stand
21
are connected with each other via first and second posts
26
,
27
constructed in such a manner that the second post
27
can be inserted into or put out from the first post
26
after unlocking a control knob
28
. That is, a height of the heat generating unit
10
can be arbitrarily adjusted.
In addition, referring to
FIG. 2
in which the heat generating unit of the radiant electric heater is shown in an enlarged scale, the heat generating unit
10
comprises the heating wire
12
wound around a heating wire mount
11
of a predetermined shape, the reflector
13
placed behind the heating wire, a safety net
14
connected to the reflector for defining a front contour of the whole heat generating unit
10
, and a supporting case
15
connected to a rear end of the reflector
13
for supporting the reflector. Furthermore, the heating wire
12
is connected to the reflector
13
via a bracket
16
, and rods
17
for sensing the heat are attached to the front of the reflector at desired positions thereof.
Accordingly, heat rays a from the heating wire
12
are concentrated within the predetermined range by the reflector
13
, contrary to the conventional structure in which the heat rays are diffused in all directions. Consequently, the heat generated from the heating wire can reach a position to be heated across a considerable distance. At this time, the heat rays a do not remain in the vicinity of the heat generating unit
10
including the heating wire
12
, but are immediately emitted from the heat generating unit through a reflecting process of the reflector
13
. Thus, overheating of the safety net
14
can also be prevented.
Here, a phenomenon that the heat rays are concentrated to the utmost can be obtained in a case where the reflector
13
is configured to have a parabolic surface with a central portion thereof being concave and to include a regular spherical surface such as in a general concave mirror.
Moreover, the heating wire mount
11
, which is generally made of a heat-resistant material such as ceramic and around which the heating wire
12
is wound, is configured in the form of a truncated cone or a circular cone of which diameter is decreased in a rearward direction so that all the heat rays a from the heating wire
12
are caused to be directed toward the reflector
3
and can thus be prevented from being diffused out of the predetermined range C. At this time, even though the mount
11
is configured in the form of a triangular pyramid or polygonal pyramid rather than the truncated cone, the object of the invention can be sufficiently achieved. That is, any types of mounts
11
of which sectional areas are reduced in the rearward direction may be employed in the invention.
It is apparent that such an electric heater has superior thermal efficiency. However, since the heating wire of the electric heater is made in the form of a coil, the coil may be corroded if it is used for a long time. Thus, there is another problem in that durability in use is deteriorated and risk of fire is increased.
Accordingly, an electric heater disclosed in Korean Utility Model Registration No. 214840 has been developed. The electric heater is configured such that a halogen lamp is used as a heat generating means and a reflector is installed in front of the halogen lamp and fixed to a safety net.
FIG. 3
is a front view of the electric heater of the utility model registration, and
FIG. 4
is an enlarged sectional view taken along line A—A of FIG.
3
. The electric heater of the '840 utility model registration includes a reflector with a heat generating means added thereto and a safety net installed in the formed of the reflector. The electric heater further comprises a halogen lamp fixing plate
50
with a fixing hole
51
(not shown) for allowing electrical power to be supplied to the halogen lamp
40
and fixing the halogen lamp
40
horizontally, an auxiliary reflector
60
installed to correspond to a central bent portion of the halogen lamp
40
for causing heat therefrom to be reflected onto the reflector
30
, and a reflector fixture
32
of which one end is connected to the auxiliary reflector
60
and the other end is fixed to a central portion of the safety net
31
.
Preferably, the halogen lamp
40
is fixed to the halogen lamp fixing plate
50
with a ceramic materi
Jeffery John A.
Smith Patent Office
Solartech Co., Ltd.
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