Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
CA 02878762 2015-01-16
- 1 -
A POWER OFF DEVICE TO AVOID FIRE ACCIDENTS OF
ELECTRIC COOKING APPLIANCES AND ELECTRIC DRYERS
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to fire prevention of electric cooking
appliances and
electric dryers.
Overheating food on cooking appliances or overdrying clothes in dryers may
cause a
fire accident. According to the statistics of NFPA, nearly 50% of residential
fire accidents were
caused by cooking appliances and dryers. In North America, most of cooking
appliances and
dryers used in residential units are powered by electricity.
2. Description of the Related Art
Currently, there are several kinds of fire prevention devices of electric
cooking
appliances in the market. They are based on the same working principal; and
mainly comprise
of power off switch, control panel, motion sensor as well as connection cable.
During a
cooking time, if people leave cooking area so that the motion sensor can't
receive the motion
signal from people anymore, the power of electric cooking appliances will be
shut off after
a pre-set time. These devices prevent fire accidents of electric cooking
appliances in this way.
Technically speaking, they have two important defects. Firstly, sometimes
shutting power off
is not necessary because during a cooking time people leaving cooking area
does not always
mean that a fire accident will happen inevitably. If cooking is going on
normally, it is not
necessary to shut the power of electric cooking appliances off after a pre-set
time. Secondly
sometimes shutting the power off is not effective. If a fire accident of
electric cooking
appliance happens after people leaving and before the pre-set time of power
off, these devices
can do nothing. In addition, these devices use a cable to transmit control
signal, it restricts
CA 02878762 2015-01-16
-2 -
the installation flexibility of these devices. Users have to often input pre-
set time on these
devices, it brings inconvenience for users.
OBJECTIVE AND ADVANTAGES
The object of this present invention is to provide a power-off device to avoid
fire
accidents of electric cooking appliances and electric dryers necessarily,
effectively and
conveniently. It is practicable to achieve a device of this invention by
directly integrating and
assembling conventional smoke/temperature alarm, wireless remote switch,
wireless remote
control and a few other electronic parts.
SUMMARY OF THE INVENTION
According to the present invention, the power-off device comprises a control-
execution
unit, at least one smoke/temperature detector and at least one power-on reset
controller. The
communication between the control-execution unit and the smoke/temperature
detector is
based on wireless signal transmission. The communication between the control-
execution unit
and the power-on reset controller is based on either wireless signal
transmission or wired
signal transmission.
According to the present invention, the smoke/temperature detector continues
to detect
the smoke and temperature around electric cooking appliances or electric
dryers in every
moment; when the smoke or temperature reaches a dangerous level, the detector
transmits a
wireless alarm signal. Once receiving the wireless alarm signal from the
detector, the
control-execution unit immediately shuts the power supply of electric cooking
appliances or
electric dryers off so that the overheating or overdrying will not happen. At
least one power-on
reset controller is used for restoring the power supply.
The control-execution unit can be separated with electric cooking appliances
or electric
CA 02878762 2015-01-16
- 3 -
dryers; the connection with electric cooking appliances or electric dryers is
achieved through a
power supply cable. For instance, there is a power outlet on the control-
execution unit; the
connection can be achieved by plugging the plug of electric cooking appliances
or electric
dryers into this outlet. The control-execution unit receives electricity from
power output in
room. There still is another way to use the control-execution unit. The
control-execution unit
can be fixed on or inside electric cooking appliances or electric dryers. In
this case, it can be
arranged and used as a component of electric cooking appliances or electric
dryers. For
instance, the power input of electric cooking appliances or electric dryers
can be firstly
introduced to the control-execution unit, and then introduced to electric
cooking appliances or
electric dryers from the unit. When the control-execution unit is equipped
with an appropriate
power connection terminal, the original power connection terminal in electric
cooking
appliances or electric dryers will not be needed.
Besides the parts used for the purposes above-mentioned, the control-execution
unit
comprises at least an electrically operated switching device, typically a
latching relay, used for
executing power on and off, at least a wireless remote switch used for
controlling the
electrically operated switching device, and a power module used for operating
the electrically
operated switching device and wireless remote switch. All these parts used are
conventional
electronic products, which can be purchased from the market or assembled by
oneself
according to prior technology. When adopting a wireless remote switch, make
sure that it uses
the same wireless frequency as the smoke/temperature detector and wireless
power-on reset
controller are using, and it is able to be compatible with the wireless
encoding types used by
the smoke/temperature detector and wireless power-on reset controller.
The smoke/temperature detector in the present invention is conventional smoke
alarm,
and smoke-temperature dual function alarm with wireless alarm signal
transmission function.
These types of alarms have been used in fire protection engineering for many
years. There are
CA 02878762 2015-01-16
-4 -
many such alarm products in the market; some of them can send wireless alarm
signal and
sound alarm at the same time. The smoke/temperature detector used can be
purchased from the
market or assembled by oneself according to prior technology. In order to
ensure an effective
wireless communication with the wireless remote switch in the control-
execution unit, the
both have to work in the same wireless frequency and use the same or
acceptable encoding
type. The detector can be fixed around and above electric cooking appliances
or electric dryers
typically on the ceiling above them. For electric dryers, the detector
especially temperature
detector can be fixed inside the drum of electric dyers.
The power-on reset controller in this invention can be a wireless remote
control. In
order to ensure an effective wireless communication with the wireless remote
switch in the
control-execution unit, the both have to work in the same wireless frequency
and use the same
or acceptable encoding type. Such wireless remote controls can be purchased
from the market
or assembled by oneself according to prior technology. In many cases, such
wireless remote
controls are sold together with the wireless remote switches in pairs. Also,
the power-on reset
controller in this invention can be an electrical switch; it communicates with
the control
-execution unit through a cable.
BRIEF DESCRIPTION OF THE DRAWINGS
The present invention will be described in more detail hereinafter by means of
the
preferred embodiment with reference to the following figures:
Fig. I shows all the components of the preferred embodiment.
Fig. 2 shows power outlet (socket side) and wireless remote switch used in the
preferred embodiment.
Fig. 3 shows power outlet (connection terminal side) and power module used in
the
preferred embodiment.
CA 02878762 2015-01-16
-5 -
Fig. 4 shows power outlet (connection terminal side) and latching relay used
in the
preferred embodiment.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
In Fig. 1, 1 is a control-execution unit. 2 is a wireless remote control,
which is used
as the power-on reset controller here. 3 is a smoke/temperature combined
detector with
wireless alarm signal transmission function. 2 and 3 all work in the wireless
frequency of
433MHZ and use the wireless encoding of EV1527. 4 is a power plug that is
connecting
with the control-execution unit through a power cable; AC power supply is
input to the
control-execution unit by plugging 4 into a power outlet in room. 5 is a power
outlet fixed
on the control-execution unit; power supply is output to electric cooking
appliances through it.
3 is installed on the ceiling above electric cooking appliances; do not
install it too close to
electric cooking appliances so as to reduce false alarms. When the smoke or
temperature
reaches a dangerous level, 3 will transmit a wireless alarm signal. Once
receiving this wireless
Is alarm
signal, 1 will immediately shut off the power output on 5. 2 is used for
restoring the
power supply. Pressing the RESET button on 2 will transmit a wireless signal,
I can restore
the power output on 5 according to this RESET signal.
In Fig. 2, 5 is the power outlet mentioned above. 6 is a wireless remote
switch, it
works in wireless frequency of 433MHZ and is able to compatible with wireless
encoding of
EV1527. 6 has two sets of normally open output channels. The first channel is
connected
with the "Switch Off' controlling coil of the latching relay (8, showed in
Fig. 4); the second
channel is connected with the "Switch On" controlling coil of the relay. When
6 receives the
alarm signal from the detector, its first output channel becomes closed for
several seconds so
that the "Switch Off' controlling coil is powered on for several seconds. When
6 receives the
RESET signal from the power-on reset controller, the second channel becomes
closed for
CA 02878762 2015-01-16
=
- 6 -
several seconds so that the "Switch On" controlling coil is powered on for
several seconds.
In Fig. 3, 5 is the power outlet mentioned above, now it is being shown from
its
connection terminal side. Except for one live wire, other wires used for
inputting AC power
supply are fixed on its connection terminal. 7 is a power module, which is
able to output IA
12VDC to the wireless remote switch and the latching relay as their power.
In Fig. 4, 5 is the power outlet mentioned in the above paragraph. 8 is a
latching
relay with a current-carrying capability of 100A 240 VAC. The latching relay
has one set of
output terminal. The ON/OFF status of this output terminal is controlled by
two controlling
coils inside the relay. When "Switch ON" controlling coil is powered on for
several seconds,
the output terminal will be in and keep "ON" ; when "Switch OFF" controlling
coil is powered
on for several seconds, the output terminal will be in and keep "OFF". The
exceptive live wire
mentioned in the above paragraph is firstly introduced to the output terminal
of 8 and then
introduced to the connection terminal of 5. As a result, the power output on 5
is controlled by
the latching relay, and finally controlled by the smoke/temperature detector
and the power-on
reset controller.
The foregoing descriptions of preferred embodiments of the present invention
have
been presented for purposes of illustration and description only. They are not
intended to be
exhaustive or to limit the present invention. Accordingly, many modifications
or variations
will be possible in light of the above teaching. The scope of the present
invention is defined by
the appended claims.
