U.S. patent application number 10/666180 was filed with the patent office on 2005-03-17 for gas flow control for gas burners utilizing a micro-electro-mechanical valve.
This patent application is currently assigned to General Electric Company. Invention is credited to Bessler, Warren Frank, Fortin, Jeffrey Bernard, Haynes, Joel Meier, Seeley, Charles Erklin.
Application Number | 20050058959 10/666180 |
Document ID | / |
Family ID | 34274700 |
Filed Date | 2005-03-17 |
United States Patent
Application |
20050058959 |
Kind Code |
A1 |
Fortin, Jeffrey Bernard ; et
al. |
March 17, 2005 |
Gas flow control for gas burners utilizing a
micro-electro-mechanical valve
Abstract
An electronically controlled gas burner system and method using
a micro-electro-mechanical (MEMS) valve. The system includes at
least one gas burner and MEMS valves comprising an array of
microvalves in fluid communication with the gas burner. The system
also includes a microvalve controller for controlling the opening
of each of the microvalves in the MEMS valve. The MEMS valve may be
positioned remote from, or within, the gas burner. A method for
controlling microvalves in a MEMS valve for firing a gas burner may
include issuing a command for a desired gas flow and controlling an
opening of at least some of the microvalves in the array to provide
the desired gas flow corresponding to the command.
Inventors: |
Fortin, Jeffrey Bernard;
(Niskayuna, NY) ; Bessler, Warren Frank;
(Amsterdam, NY) ; Haynes, Joel Meier; (Niskayuna,
NY) ; Seeley, Charles Erklin; (Niskayuna,
NY) |
Correspondence
Address: |
General Electric Company
CRD Patent Docket Rm 4A59
Bldg. K-1
P.O. Box 8
Schenectady
NY
12301
US
|
Assignee: |
General Electric Company
|
Family ID: |
34274700 |
Appl. No.: |
10/666180 |
Filed: |
September 17, 2003 |
Current U.S.
Class: |
431/12 |
Current CPC
Class: |
F23N 2235/18 20200101;
F23N 1/002 20130101; F23N 2900/01001 20130101; F23C 2900/03001
20130101 |
Class at
Publication: |
431/012 |
International
Class: |
F23N 001/00 |
Claims
1. An electronically controlled gas burner system comprising: at
least one gas burner; a micro-electro-mechanical valve comprising a
plurality of microvalves in parallel fluid communication with the
gas burner; and a microvalve controller for controlling the opening
of each of the microvalves in the micro-electro-mechanical
valve.
2. The system of claim 1, wherein the micro-electro-mechanical
valve is positioned remote from the gas burner.
3. The system of claim 1, wherein the micro-electro-mechanical
valve is positioned within the gas burner.
4. The system of claim 1, wherein the micro-electro-mechanical
valve is coupled to a plurality of gas burners.
5. The system of claim 4, wherein a portion of the plurality of
microvalves in the micro-electro-mechanical valve is coupled to a
respective one of the plurality of gas burners.
6. The system of claim 1, wherein the microvalve controller further
comprises a module to selectively control an opening of each of the
microvalves for controlling a gas output.
7. The system of claim 1, wherein the module comprises a pulse
width modulator.
8. The system of claim 1, wherein the microvalve controller is
further coupled to an electronic interface programmable by a
user.
9. The system of claim 1, wherein the microvalve controller is
further coupled to a sensor positioned proximate the burner.
10. An electronically controlled gas burner system comprising: at
least one gas burner; and a micro-electro-mechanical valve
comprising a plurality of independently controllable microvalves in
parallel fluid communication with the gas burner.
11. (canceled)
12. The gas burner of claim 10, further comprising a microvalve
controller for controlling an opening of each of the
microvalves.
13. The gas burner of claim 12, wherein each of the microvalves is
configured to contribute to a flame when opened by the microvalve
controller.
14. The gas burner of claim 12, wherein the microvalve controller
further comprises a pulse width modulator to modulate the opening
of each of the microvalves for controlling a gas output.
15. The gas burner of claim 14, wherein the pulse width modulator
operates at duty cycle in the range of between 90% and 10%.
16. The gas burner of claim 15, wherein the pulse width modulator
operates at duty cycle in the range of between 60% and 40%.
17. A gas valve comprising a plurality of microvalves in parallel
fluid communication with a gas burner of a cooking appliance.
18. The gas valve of claim 17, further comprising a microvalve
controller for controlling the opening of each of the
microvalves.
19. A method for controlling to a gas burner comprising: issuing a
command for a desired gas flow; and controlling opening of at least
some of a plurality of independently controllable microvalves in
parallel fluid communication to provide the desired gas flow
corresponding to the command.
20. The method of claim 19, further comprising allocating a portion
of the plurality of microvalves to a respective burner of a
multiburner appliance.
21. The method of claim 19, wherein controlling an opening of each
of the microvalves comprises driving the microvalve to be fully
open.
22. The method of claim 19, further comprising: issuing a feedback
command to adjust the gas flow; and adjusting the gas flow by
changing the opening of at least some of the microvalves.
23. The gas valve of claim 17, wherein the plurality of microvalves
are independently controllable.
Description
FIELD OF THE INVENTION
[0001] The present invention is generally related to cooking
appliances, and, more particularly, to a micro-electro-mechanical
(MEMS) valve for providing a variable gas flow control for gas
burners.
BACKGROUND OF THE INVENTION
[0002] Gas cooking ranges typically include a manually operated gas
valve positioned in a gas line between a gas source and a burner to
control gas flow to the burner. Turning of an indicator knob
connected to the gas valve selectively opens or closes an orifice
in the valve to allow gas to flow through the burner. Unlike
electric heating elements that may be electronically controlled and
programmed, a user must directly control gas flow in typical gas
cooking range, and changes to the flow can only be made by
physically moving the knob to adjust the gas flow. To achieve
remote control and programmability of gas burners, advanced gas
burner ranges may incorporate proportional solenoid valves, motor
driven valves, or binary poppet valves, for example, controlled via
an electronic touch pad. However, such electro-mechanical controls
are not suited for appliances because they are complex, require a
relatively large footprint for incorporation in a gas range, may be
less reliable than manual valves, may not be suitable for use in a
high heat environment, and may be prohibitively expensive to
manufacture and maintain. In addition, proportional control at low
gas flows using electro-mechanical controls has been difficult to
achieve. Micro-electro-mechanical system (MEMS) valves have been
proposed for low flow, high-pressure applications. Typical MEMS
valves may include a silicon or polymer based microvalve, and may
be operated by electrostatic, electromagnetic, shape memory alloy
(SMA) or piezoelectric actuation. However, such valves are not
believed to be suited for low pressure, high flow applications.
BRIEF DESCRIPTION OF THE INVENTION
[0003] An electronically controlled gas burner system is presented
that includes at least one gas burner and a
micro-electro-mechanical valve comprising a plurality of
microvalves in fluid communication with the gas burner. The system
also includes a microvalve controller for controlling the opening
of each of the microvalves in the micro-electro-mechanical
valve.
[0004] A method for controlling a plurality of microvalves for
firing a gas burner is presented that includes issuing a command
for a desired gas flow and controlling an opening of at least some
of the microvalves valves to provide the desired gas flow
corresponding to the command.
BRIEF DESCRIPTION OF THE DRAWINGS
[0005] FIG. 1 is an exemplary diagram of a gas burner system
comprising a MEMS valve coupled to a burner.
[0006] FIG. 2 is an exemplary diagram of a gas burner system
comprising a MEMS valve having portions of a plurality of
microvalves coupled to respective burners.
[0007] FIG. 3 is an exemplary diagram of a gas burner comprising an
array of microvalves.
DETAILED DESCRIPTION OF THE INVENTION
[0008] FIG. 1 is an exemplary diagram of a gas burner system 10
comprising a micro-electro-mechanical system (MEMS) valve 12
coupled to a burner 14. The MEMS valve 12 may include one or more
microvalves 16, for example, configured in an array. Each of the
microvalves 16 may be coupled, for example, by an electrical
conductor, to a valve controller 18 for controlling the opening and
closing of each of the microvalves 16 in the MEMS valve 12. An
output 17 of each of the microvalves 16 may be in fluid
communication with the burner 14, and an input 15 to the each of
the microvalves 16 may be in fluid communication with a gas supply
20. Accordingly, each of the microvalves 16 in the MEMS valve 12
may be independently controlled to open or close the microvalves
16, allowing gas to flow from the gas supply 20 to the burner 14 at
a desired rate.
[0009] In the past, it was believed that the low flow
characteristics of conventional MEMS valves precluded their use in
gas burner applications. However, the inventors of the present
invention have innovatively realized that by using an array of
microvalves, improved electronic control of gas burners may be
provided. Moreover, because the microvalves may be individually
operated, proportional control, offering fine control at low burner
powers, may be provided. Furthermore, a MEMS valve incorporating a
number of microvalves in an array configuration offers the
advantages of low cost, reliability, simplicity, small footprints,
and heat resistance. Examples of microvalve devices that were used
in a prototype constructed for experimental purposes include those
as described in U.S. Pat. Nos. 6,149,123 and 6,523,560. It will be
appreciated that the present invention is not limited to the
foregoing devices since the array aspects of the present invention
may be practiced with any type of microvalve devices.
[0010] In an aspect of the invention, the microvalves 16 in the
MEMS valve 12 may be operated in a continuously variable, or
analog, fashion to provide a variable range of microvalve 16
openings, and consequently, variable gas flow from the valve,
depending on a degree of opening of the microvalve 16. In another
aspect of the invention, the microvalves 16 in the MEMS valve 12
may be operated in a binary fashion. For example, the microvalve
controller 18 may provide a two state control signal having a first
state for controlling a microvalve 16 to a closed position, and a
second state for controlling the microvalve 16 to an open position.
Accordingly, different numbers of microvalves 16 in the MEMS valve
12 may be opened or closed to provide variable gas flow. For
example, in an array comprising ten microvalves 16, one of the
microvalves 16 may be opened to provide a lowest setting for gas
flow to the burner 14. Progressively larger numbers of microvalves
16 may be opened to provide increasingly higher gas flows.
Accordingly, all 10 of the microvalves 16 in the MEMS valve 12, may
be opened to provide a highest setting for gas flow. In an aspect
of the invention, the number of microvalves 16 selected for the
MEMS valve 12 may be based on the total gas flow required to fire
the burners 14 at a desired burner rating, and the gas flow
capability of each valve 12. For example, if a burner requires a
total gas flow of 0.18 standard cubic feet per minute (SCFM) to
operate at a desired BTU capability, and each valve in the array
can provide 0.018 SCFM, then ten valves (10.times.0.018=0.18 SCFM)
may be used to control the gas flow to the burner.
[0011] In yet another aspect, the microvalve controller 18 may
include another module, such as a pulse width modulator (PWM) 24,
to sequentially turn each of the microvalves 16 on and off
periodically at a desired duty cycle when the respective microvalve
16 is turned on by the microvalve controller 18. For example, a
duty cycle of from 90% to 10% may be used, while a duty cycle of
60% to 40% is believed to promote most stable burning. By
modulating the opening and closing of each of the microvalves 16 in
this manner, it is believed that combustion in the burner 14 may be
made more efficient.
[0012] In another aspect of the invention, the microvalve
controller 18 may be programmed via an electronic interface 22. For
example, the electronic interface 22 may include a user interface,
such as a touch pad, to allow a user to control a burner 14 gas
flow setting for cooking. The electronic interface 22 may also
provide a programmed gas flow pattern that varies with respect to
time, such as an initial comparatively higher flow rate for first
desired time period and a comparatively lower flow rate for a
second desired time period. In addition, the electronic interface
22 may allow remote control of the gas burners 14 via a
communications interface such as Bluetooth.RTM., registered by
Bluetooth SIG, Inc, compatible interface.
[0013] The system 20 may also include at least one sensor 26 to
monitor a burning condition at the burner 14. For example, the
sensor 26 may be positioned near the burner 14 for monitoring
conditions such as temperature or carbon monoxide formation. The
sensor 26 may provide such information to the microvalve controller
18 in a feedback loop 28. The microvalve controller 18 may then
control the opening of at least some of the microvalves 16 to
adjust the gas flow to the burner 14 according to the information
received from the sensor 26.
[0014] FIG. 2 is an exemplary diagram of a gas burner system 30
comprising a MEMS valve 12 having portions 32, 34, 36, 38 of an
array of microvalves 16 coupled to respective burners 14. For
example, each burner 12 may be fluidically connected to a
respective portion 32, 34, 36, 38, and each portion may be
controlled by the microvalve controller 18. In FIG. 2, gas input
connections for a gas source, such as the gas source 20 shown in
FIG. 1, have been omitted for clarity. As depicted in FIG. 2, the
MEMS valve 12 may be centrally located with respect to a plurality
of burners 14 so that different portions 32, 34, 36, 38 of the MEMS
valve 12 may be used to fire each of the burners 14. For example,
the microvalve controller 18 may be configured to provide
independent control of each portion 32, 34, 36, 38 of the MEMS
valve 12. In addition, each valve 12 in each portion 32, 34, 36, 38
may be controlled independently to provide variable gas flow to the
burner 12. Each portion 32, 34, 36, 38 may include an appropriate
number of microvalves 16 to provide a gas flow required to fire the
respective burner 12 coupled to the portion 32, 34, 36, 38. The gas
burner system 30 may further include the elements described above,
such as a PMW module 24, an electronic interface 22 and a sensor 26
as shown in FIG. 1.
[0015] FIG. 3 is an exemplary diagram of a gas burner 40 comprising
an array of MEMS microvalves 16. In FIG. 3, gas connections to the
inputs 15 of each of the microvalves 16 to a gas source, such as
the gas source 20 shown in FIG. 1, have been omitted for clarity.
In an aspect of the invention, the microvalves 16 may be positioned
integrally or otherwise within the burner 40 to contribute to a
flame produced by the burner 40. For example, the microvalves 16
may be positioned circumferentially in a circular burner so that
the output 17 of each the microvalves 16 is oriented to contribute
to flames around a periphery of the burner 12. Each of the
microvalves 16 may be independently controlled by the microvalve
controller 18 to open or close the microvalves 16 to allow gas to
flow from the microvalves 16 at a desired rate. The gas burner
system 30 may further include the elements described above with
respect to FIG. 1, such as a PMW module 24, an electronic interface
22 and a sensor 26 as shown in FIG. 1
[0016] It is believed that a MEMS valve comprising an array of
microvalves as described above could be constructed as follows. For
example, the MEMS valve may be configured to have a 15.times.15
millimeter (mm) footprint and include 100 microvalves. The
microvalves may be grouped in groups of 10. Each group of 10 valves
may be configured to have a collective binary action, so that
either all valves in the group are fully open, or completely
closed. Accordingly, ten different cumulative flow levels may be
provided. Each group may be configured to provide a flow level of
0.0180 SCFM, so that a flow level of 0.0180 SCFM is provided when
one group is "on" (for example, for a low cooking setting) and 10
times 0.0180 SCFM or 0.180 SCFM when all ten groups are "on" (for
example, for a high cooking setting.) The exemplary MEMS valve may
include microvalves having piezoelectric polymer actuation, and be
a normally closed type microvalve.
[0017] It is believed that a MEMS valve configured as described
above could provide electronically controlled proportional flow and
operate at 2 to 10 inches of water (iwc). The flow variation may be
less than +/-10% at a minimum flow and +/-5% at a maximum flow. The
microvalves may have a 0.25 second response time. It is believed
each of the valves could operate for 100,000 cycles with 95%
confidence level. Furthermore, it is believed the array controller
would use less than 10 watts of electrical power to control the
microvalves in the array.
[0018] While the preferred embodiments of the present invention
have been shown and described herein, it will be obvious that such
embodiments are provided by way of example only. Numerous
variations, changes and substitutions will occur to those of skill
in the art without departing from the invention herein. While an
exemplary embodiment of a cooking appliance for use in stove is
described, the invention may be used any application having a gas
burner. Accordingly, it is intended that the invention be limited
only by the spirit and scope of the appended claims.
* * * * *