Note: Descriptions are shown in the official language in which they were submitted.
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S7<NGLE-STAGY GAS 'VAL'VE
$aclcaroand of tlae 1<nvention
Field oCthe Invention
The present invention generally relates to gas valves and burner
assemblies, and more specif tally relates to a single stage gas valve that is
regulated
based on flame conditions at the burner assembly.
Related Art
Gas burners are used in a variety of applications including, for
example, fireplaces, boilers, hot water heaters, furnaces, gas grills, cooking
stoves
and ovens, lanterns, etc. In each application, the gas btuzzer must meet
specifications
related to, for example, available power, efficiency ratings, safety, etc.
that are often
unique to that application. Most gas burners are used in combination with an
ignition system and a gas valve that controls the flow of gas fuel to the
burner for
ignition into a flame by the ignition system.
One important safety concern related to gas burners is the inadvertent
release. of unburned gas via the burner. This situation may occur if, for
example, the
ignition system fails to propezly ignite the flame and the gas valve remains
open,
resulting in the release of gas through the burner. If the ignition then
engages, that
can cause dangerous ignition of the gas. Tlus is sometimes called delayed
ignition.
Scone ignition systems and related burner control systems include sensors that
monitor a flame condition at the burner to ensure that a flame is present
within a
predetermined time period of the gas valve being open and the ignition system
generating a spark to ignite a flame.
Other systems include a pilot light that provides a constant
spark/flame at the burner to ensure that any gas flow that is provided to the
burner
will result in the generation of a flame that bw~ns the gas flow. The addition
of a
pilot light can add additional cost, complexity, and inefficiency to a gas
burner and
its related gas valve, ignition and control systems.
Gas burner systems used with light fixtures such as gas lanterns have
historically been at least partially manually operable. In one configuration,
such
manual systems include a manual valve that must be turned on and off, and a
separate igniter that must be activated to ignite the gas into a flame. In
other
configurations, the igniter, gas valve, or other features may at least
partially
automatically function. However, no known configurations provide automated
features that provide both safety and efficiency required to meet some types
of
CA 02501252 2005-03-17
certifications, such as CSA certificates of compliance. As a Nationally
Recognized
Testing Laboratory (NRTL) accredited by OSI-IA, CSA International can test and
certify products following standardi2ed test protocols in laboratories across
the
United States. CSA International tests to applicable U.S. standards, including
ANSI,
UL, CSA, NSF, and many others.
A gas burner that can operate without a pilot light while addressing
the safety and efficiency issues noted above would be an advance in the art.
Summary of the llnvention
The present invention relates to gas valves and burner assemblies that
are functional without the use of a pilot light. One objective of the present
invention
is to provide a gas valve, wherein an electromagnetic valve is used to control
the
output of gas to a gas burner. The electromagnetic valve is regulated based on
sensor feedback at the gas burner. The electromagnetic valve is closed if a
flame is
not sensed at the burner when the flame is intended to be present, and
maintains an
open position if the flame is sensed when intended to be present.
One aspect of the invention relates to a combustion assembly that
includes a single stage gas valve, a burner member having a flame end, a spark
generating member, a flame sensing member, and a controller. The spark
generating
member generates a spark in response to a spark signal and is positioned
adjacent to
the flame end ofthe brunet member. The flxtne sensing member senses the
presence
of a flame and is also positioned adjacent to the flame end. The controller
provides
a valve open signal to the valve to control a flow of gas to the burner
member,
provides a spark sisal to the spark generating member to generate a spark that
ignites the flow of gas, receives a flame sense signal from the flame sensing
member
related to the state of the flame, and provides a valve closed signal to stop
the flow
of gas when the flame sense signal indicates no flame is present.
Another aspect of the invention relates to a gas burner assembly that
includes a single stage gas valve, a burner device, a flame sense device, and
an
ignition device. The burner device of the combination includes a gas outlet at
a
flame end of the burner device and is configured to generate a flame that
extends
from the flame end. The gas valve of the combination is a single stage gas
valve
that is movable between a closed position wherein no gas flow is provided to
the
burner device and an open position wherein a gas flow is provided to the g~
outlet
of the burner device. The flame sense device of the combination is positioned
adjacent to the flame end of the burner device and is configured to provide a
flame
signal indicative of the presence of the flame. The ignition device of the
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CA 02501252 2005-03-17
combination is also positioned adjacent to the flame end of the burner device
and is
configured to provide a spark when the gas valve is open, the spark igniting
the flow
of gas out of the gas outlet of the burner device to generate the flame. The
gas valve
closes when the flame signal indicates that no flame is present.
A further aspect of the inv ention relates to a method of generating
and monitoring a flame with a combustion assembly, the combustion assembly
including a gas valve, a borne- device, an ignition system, and a flame sense
member. The gas valve includes a regulator member that controls the flow of
gas
out of the gas valve. The burner device includes a gas outlet at a flame end
of the
burner device. The method includes opening the gas valve with the regulator to
provide a flow of gas from the gas valve to the gas outlet of the burner
device,
generating a spark with the ignition system for igniting the flow of gas into
a flame
at the flame end of the burner device, sensing the state of the flame with the
flame
sense member, and closing the gas valve when the presence of the flame is not
sensed by the flame sense member.
A still further aspect of the invention relates to a lantern single stage
gas valve and burner assembly that includes a valve housing, a moveable plate,
a
magnetoresistive member, a power source, and a burner assembly. The valve
housing includes a gas inlet and a gas outlet and the moveable plate is
positioned
between the gas inlet a~.~d the gas outlet to control gas flow through the
valve
housing. The magnetoresistive member is configured to move the moveable plate
upon activation by a power input. The power source provides the power input in
the
range of about 1 to 6 volts DC. The burner assembly is coupled to the housing
and
configured to produce a flame. The magnetoresistive member automatically moves
the moveable plate to stop gas flow when no flame is present at the burner
assembly.
The above summary of the present invention is not intended to
describe each disclosed embodiment or every implementation of the present
invention. The Figures and the detailed description that follow more
particularly
exemplify certain embodiments of the invention. While certain embodiments will
be illustrated and describe embodiments of the invention, the invention is not
limited
to use in such embodiments.
Brief Description of the Drawings
The invention may be more completely understood in consideration
of the following detailed description of various embodiments of the invention
in
connection with the accompanying drawings, in which:
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Figure 1 is a perspective view of an assembly in a possible
embodiment of the present invention;
Figure 2 is an exploded perspective view of the assembly of Figure 1;
Figure 3 is a front view of the assembly of Figure 1;
Figure 4 is a side view of the assembly of Figure 1;
Figure 5 is a top view of the assembly ofFigtu-a 1;
Figure 6 is a cmss-sectional view of the assembly shown in Figure 5
taken along cross-sectional indicators 6-6;
Figure 7 is a schematic circuit diagram for the assembly of Figure I;
Figure 8 is an example gas lantern that includes the assembly of
Figure 1;
Figure 9 is a cross-sectional view of the gas lantern shown in Figure
8; and
Fi~ure 10 is a flow diagram illustrating steps of an example method
of using the assembly shown in Figure I .
While the invention is amenable to various modifications and
alternate forms, specifics thereof have been shown by way of example and the
drawings, and will be described in detail. It should be understood, however,
that the
intention is not to limit the invention to the particular embodiments
described. On
the conuary, the intention is to cover all modifications, equivalents, and
alternatives
falling within the spirit and scope of the invention.
Detailed Descriui~on of the )Preferred Embodiment
The present invention generally relates to gas valve and burner
assemblies and related sensing, ignition, and control systems. More
specifically, the
present invention relates to a combustion system or assembly that includes a
single
stage valve, a bunter member having a flame end, a spark generating member, a
flame sensing member, and a controller. The controller sends and receives
signals
related to the flow of gas from the gas valve to the burner member, the
generation of
a spark to ignite a flame at the flame end of the burner member, and a sensed
state of
the flame provided by the flame sensing member. This example conficuration
provides generation and monitoring of a flame without the use of a pilot flame
or
pilot valve, thus reducing the complexity and cost of the combustion system as
compared to some known combustion systems. In some embodiments, this example
configuration is operable using solely a DC power input, making it possible to
operate the system use a low voltage battery pack rather than an AC power
input.
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CA 02501252 2005-03-17
As used herein, the terms "combustion system" and "combustion
assembly" relate to a system or device that is configured to combust a
combustible
material such as natural gas or liquid propane in a controller manner. A
"controller"
as used herein may be any control device such as a microprocessor or assembly
of
circuit components that sends and receives signals. A "single stage valve" is
defined
as a valve having valve components that controls a single input and output
flow of
fluid through the valve.
Referring now to Figures 1-6, an example combustion assembly 10 is
shown and described. Assembly 10 includes a single stage valve 12, a burner
member 14, an ignition member 16, a flame sense member 18, a mounting bracket
20, a gas conduit 22, and a controller 24. The controller 24 controls the
generation
of a flame at the burner 14 in response to an open or closed position of the
valve 12,
sparks generated by the ignition member 16, and a state of the flame
deterniined by
the flame sense member 18.
The single stage valve 12 includes a base 30, a cover 32, a seal 34, a
regulator 36, an electzomagnetic member 50, a movable valve plate 52, a
conduit 54,
a shield 56, and a valve connector cable 58. The base 30 includes an inlet
collar 40;
an outlet collar 42, an inlet channel 44, and an outlet channel 46. The
regulator 36
controls a position of th.e moveable valve plate 52 in response to open and
close
valve signals from the controller 24. The regulator 36 applies an electric
charge to
the electromagnetic member 50 that creates an axial force, which when applied
to
the plate 52 can move the plate 52 relative to an opening 55 into the conduit
54. The
shield 56 provides both physical and electrical shielding of the plate 52 to
ensure
that the plate maintains the open or closed position. When the plate 52 is in
the open
position relative to opening 55, gas flows through the inlet channel 44,
through the
opening 55 into the conduit 54, and through the outlet channel 46 into the gas
conduit 22 'for combustion at the burner member 14.
While the valve 12 is well suited for providing precise control of
fluid flow through the valve in response to an incoming signal from the
controller
3U 24, other valve embodiments may be used. For example, a m.agn.etic motor, a
stepper motor, or a linear actuator could be used to control gas flow to the
burner
member 14.
The burner member 14 includes a flame opening 60 at a flame end
61, and a grounding member 62 having an end tip 64. The burner member 14 has a
generally elongate body with a conduit 65 extending along the length of the
burner
mEmber 14 (see Figure 6). The conduit 65 is oriented substantially coaxially
with
the gas conduit 22 and the inlet and outlet collars 40, 42 of the valve 12. As
a result,
CA 02501252 2005-03-17
the combustion assembly 10 has a generally elongate configuration, which makes
it
possible for the combustion assembly 10 to fit within an elongate structure
such as,
for example, a cylinder having a diameter no smaller than a maximum width W
(see
Figure 3) of the combustion assembly 10. One application for a combustion
assembly having the elongate construction shown in Figures 1-6 is useful with
a gas
lantern, wherein the combustion assembly 10 is positioned within a cylindrical
post
that supports the lamp. An example lamp assembly is shown and described in
~(J.S.
Patent Application Serial No. 10/803,535 filed on March I7, 2004, and entitled
Gras
Light Systems and Methods of Operation.
The ignition member 16 includes a sparking tip 70 and a connector
cable 72. The ignition member 16 is structured and mounted to the mounting
bracket 20 at a position so as to orient the spark tip 70 at a preferred
distance from
the flame opening 60 of the burner member 14. Due to the spacing between the
spark tip 70 and the flame end 61 of the burner member 14 that is preferred
for
1 S minimizing obstntction of the flame, the ignition member 16 may have
difficulty
generating a spark when using the flarne end 61 as an electrical ground
member.
Typically, the burner member 14 provides the ground through which the spark
tip 70
creates a spark. To reduce the distance between the grounding member and the
spark tip 70, the grounding member 62 bas been added to the burner member 14.
The grounding member 62 may include a pointed end tip 64 that provides minimal
interruption of the flame shape while still providing the desired grounding
function.
In some embodiments, grounding can be provided with a two-wire system that
sends
power and ground co the desired sight using two or more conductors. In some
embodiments, the ignition member may function via a thermocouple-voltage
response or via a thermopile-voltage generation.
The flame sense member 18 includes a sensor tip 80 and a conductor
cable 82. The flame sense member 18 is also mounted to the bracket 20 and is
shaped so as to position the sensor tip 80 at a desired distance from the
flame end 61
of the burner member 14. The flame generated by the burner member 14 is an
ionised flame and requires grounding in order for the flame sense member 18 to
determine whether the flame is in existence. Therefore, the grounding member
62
has been included as an extension of the burner member 14 to provide a
Bounding
member in contact with the flame so as to activate sensing of the flame by the
flame
sense member I8.
Both the spark tip 70 and sensor tip 80 are sized and positioned
relative to the flame end 61 of the burner member 14 so as to provide minimal
disruption of the flame generated by the burner member. This minimized
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CA 02501252 2005-03-17
obstruction of the flame is especially important when the combustion assembly
10 is
used solely for generating light in a lantern application. 1n other
applications,
obstruction or disruption of the !lame may be less important.
Referring now to Figure 2, the bracket 20 may include first and
second members 90, 92. The members 90, 92 are configured for mounting the
valve
12 relative to the burner member 14, ignition member 16, and flame sense
member
18, and for mounting the bracket 20 to a mounting surface to wluch the
combustion
assembly 10 is secured. In other embodiments, different bracket configurations
or
additional bracket members may be used for mounting various features of the
assembly 10.
Tlte valve 12, btuner member 14, ignition member 16, flame sense
member 18, and controller 24 are operable using a relatively low power input,
and
may function using a DC voltage input. A system that requires only DC power
makes it possible to operate the system using a battery pack (e.g., battery
pack 25
shown in Figure 1) rather than an AC power source. A system that can operate
using DC battery power may be particularly useful with a gas Iantexn, wherein
the
gas lantern can be positioned at any location around a living structure or
yard
without the need for an AC power connection. Positioning of such a gas lantern
may be further unrestricted if the gas lantern uses a portable fuel source,
such as
described in U.S. Patent Application Serial No. 10/803,535. Other embodiments
may be configured for using AC power or may include a converter or other
capabilities that permit the system to function using either AC or DC power.
The controller may be a separate controller that is positioned
remotely from the valve 12, burner 14, ignition member 16; and flame sense
member 18 as shown in Figures 1, 4 and 5. However, other embodiments may
include the controller mounted directly to the valve (e.g., adjacent to the
regulator 36
on the cover 32 of the valve), or to the mounting bracket 20 or other space
interposed between various features of the combustion assembly 10. Example
devices for use as the controller include a micro-based controller arid a
series of
amplifying transistors.
Figures 8 and 9 illustrate an example gas lantern 100 that includes the
example combustion assembly L0. Some portions of the assembly 10 (e.g., the
valve 12) may be positioned within a cylindrical post 102 of the lantern 100
while
other portions of the assembly IO (e.g., the burner member 14, the io ition
mexnber
16, and the flame sense member 16) may be positioned within a light housing
104 of
the lantern 100. The lantern 100 includes an onloff switch 106 that is coupled
to the
controller 24 of the combustion assembly 10.
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Referring now to Figure 7, a schematic circuit diagram representing
the control functions ofthe combustion assembly 10 i.s shown. The specific
values
for the various components can vary depending on the system requirements.
Further, the scheazatic of Figurc 7 is only one of many configurations
possible for
providing the desired control of the combustion assembly 10. The diagram shown
in
Figure 7 functions generally to provide the method steps described with
reference to
Figure 10 given the inputs and outputs shown. '
According to a first step of the example method shown in Figure 9, a
gas valve is opened with a regulator to provide a flow of gas from the gas
valve to
the gas outlet for the burner device. As discussed above, the regulator of the
gas
valve is controlled by an open valve control signal provided by the
controller. In
some embodiments, the open valve control signal may come directly from a user
input such as, for example, by a manual activation of the valve into an open
position.
As noted above, the gas valve may include an electromagnetic member, a
moveable
valve plate, and a plurality of conduits and openings that provide for gas
flow
through the gas valve and to the outlet of the burner device for combustion
into a
flame.
Another method step includes generating a spark within as ignition
system for igniting the flow of gas into a flame at a flame end of the burner
device.
The ignition system may generate a spark between a spark tip of an ignition
member
of the ignition system and a grounding member that extends from the flame end
of
the burner member.
Another method step includes sensing the state of the flame with a
flame sensing member. The flame sensing member may include a sensor tip that
is
spaced apart from a dame end of the burner member. The Bounding member that
extends from the flame end of the burner member may provide the necessary
grounding required for the ionised flame to be sensed by the sensor tip of the
flame
sensing member. In the event that a flame has not been ignited after the gas
valve
has been opened and a spark has been generated, the flame sensing member will
provide a flame sense signal that indicates that a flame is not present. In
response to
such a flame sense signal, the gas valve is automatically closed.
In alt of the above-described steps, the controller may be used to send
and receive the various signals related to opening and closing of the gas
valve,
generating a spark, and sensing the state of the flame. The controller may
also be
used to generate the sequence of events related co the method steps, the
controller
may also be used to interpose predetermined time periods in between the
various
method steps. For example, after the controller sends a valve open signal to
open
CA 02501252 2005-03-17
the valve, the controller may wait a predetermined time period (e.g., about 1
to 2
seconds) before sending a spark signal to the ignition system for generating a
spark.
After sending the spark signal, the controller may wait another predetermined
time
period before activating the sensing member at which time the sensing member
senses the state of the flame. If a controller does not immediately receive a
sensing
signal from the flame sense member that a flame exists, the controller may
again
activate the flame sense member to sense for the state of the flame, or may
first send
another spark sio zal to the ignition system for generation of a spark prior
to
activating the sensing member again. The controller may also wait a
predetermined
time period between the time at which the controller determines that a flame
is not in
existence and when the gas valve is closed, although it is preferable for the
gas valve
to be closed immediately upon the controller determining that the flame is not
in
existenc e.
According to the above description, the system can be ~ul ly
automated during the process of igniting the flame once activated (typically
6y a
user) to start the ignition sequence) and ensuring that the flame is present
when
intended to be present. This automated system provides a relatively high level
of
safety for the system with respect to minimizing the occurrence of an
inadvertent
release of unburned gas from the burner. Furthermore, this automated system
makes
it possible to generate a controlled flame without the need for a pilot light,
thus
increasing the fuel efficiency and minimizing the complexity and cost of the
system.
The present invention should not be considered limited to the
particular examples or mzterials described above, but rather should be
mderstood to
cover all aspects of the invention as fairly set out in the attached claims.
Various
modifications, equivalent processes, as well as numerous structures to which
the
present invention may be applicable will be readily apparent to those of
sltill in the
art to which the present invention i.s directed upon review of the instant
specification.
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