U.S. patent application number 16/972115 was filed with the patent office on 2021-07-29 for indication apparatus to indicate the output level of a pilot flame and method.
This patent application is currently assigned to SIT S.P.A.. The applicant listed for this patent is SIT S.P.A.. Invention is credited to Michele Benvenuto, Massimo Giacomelli, Nicola Lovison, Federico Rattin.
Application Number | 20210231305 16/972115 |
Document ID | / |
Family ID | 1000005539855 |
Filed Date | 2021-07-29 |
United States Patent
Application |
20210231305 |
Kind Code |
A1 |
Lovison; Nicola ; et
al. |
July 29, 2021 |
INDICATION APPARATUS TO INDICATE THE OUTPUT LEVEL OF A PILOT FLAME
AND METHOD
Abstract
The present invention concerns an indication apparatus and
corresponding method to indicate the output level of a pilot flame
in a gas appliance provided with a thermocouple suitable to convert
the energy generated by a pilot flame, which receives gas from a
pilot valve, into electric voltage to power an electro valve of the
pilot valve and to keep the latter open. The apparatus comprises a
first and a second connector suitable to be coupled with a positive
terminal and with a negative terminal of the thermocouple, a
voltage measurement circuit connected to the first and the second
connector, a lighting device configured to provide a light signal,
a controller device coupled with the voltage measurement circuit
and with the lighting device and configured to determine the
switching on of the lighting device on the basis of the output
supplied by the voltage measurement circuit to provide a user with
an indication of when the voltage generated by the thermocouple is
greater than or equal to a predefined value sufficient to power the
electro valve.
Inventors: |
Lovison; Nicola; (Padova,
IT) ; Rattin; Federico; (Canal San Bovo, IT) ;
Benvenuto; Michele; (Maserada Sul Piave, IT) ;
Giacomelli; Massimo; (Venezia, IT) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
SIT S.P.A. |
Padova |
|
IT |
|
|
Assignee: |
SIT S.P.A.
Padova
IT
|
Family ID: |
1000005539855 |
Appl. No.: |
16/972115 |
Filed: |
June 11, 2019 |
PCT Filed: |
June 11, 2019 |
PCT NO: |
PCT/IT2019/050132 |
371 Date: |
December 4, 2020 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F23N 2229/02 20200101;
F23N 2231/08 20200101; F23N 2231/02 20200101; F23N 2241/08
20200101; F23N 5/102 20130101; F23N 5/107 20130101; F23N 5/242
20130101; F23N 2231/22 20200101; F23N 2223/08 20200101; F23N
2227/22 20200101 |
International
Class: |
F23N 5/10 20060101
F23N005/10; F23N 5/24 20060101 F23N005/24 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 11, 2018 |
IT |
102018000006215 |
Claims
1. An indication apparatus to indicate the output level of a pilot
flame in a gas appliance provided with a thermocouple suitable to
convert the energy generated by a pilot flame, which receives gas
from a pilot valve, into electric voltage to power an electro valve
of the pilot valve and to keep the latter open, characterized in
that said apparatus comprises: a first and a second connector
suitable to be coupled with a positive terminal and with a negative
terminal of the thermocouple; a voltage measurement circuit
connected to said first and second connectors and configured to
calculate the difference in electric voltage at the heads of the
terminals to determine the electric voltage generated by the
thermocouple and to provide an output correlated to the difference
in voltage calculated; a lighting device configured to provide a
light signal; a controller device coupled with the voltage
measurement circuit and with the lighting device and configured to
determine the switching on of said lighting device on the basis of
the output supplied by the voltage measurement circuit to provide a
user with an indication of when the voltage generated by the
thermocouple is greater than or equal to a predefined value
sufficient to power the electro valve; a battery connected to said
controller device, and configured to power the latter and the
voltage measurement circuit, and a power circuit connected between
said connectors and said lighting device, and comprising a
capacitor configured to accumulate a quantity of electric charge
supplied by the thermocouple at least sufficient to allow the
switching on of said lighting device, said power circuit being
configured to power the latter with the electric voltage supplied
by said capacitor on the basis of commands received from said
controller device in such a way as to switch on said lighting
device in a flashing manner when the voltage generated by the
thermocouple is greater than or equal to said predefined value.
2. The indication apparatus of claim 1, wherein said power circuit
comprises a second switch connected in series to said lighting
device, which can be selectively activated/deactivated by said
controller device in order to respectively allow/prevent the
electric charge accumulated in said capacitor being discharged
through said lighting device.
3. The indication apparatus of claim 2, wherein said indication
apparatus comprises a transformer configured to raise the electric
voltage generated by the thermocouple and provided with a primary
coil connected to the first and to the second connector, and with a
secondary coil connected to the heads of said lighting device,
wherein said capacitor is connected in parallel between said
secondary coil and said lighting device, and is configured to
accumulate the electric voltage supplied by said transformer.
4. The indication apparatus of claim 3, wherein said power circuit
comprises a first switch connected in series to said primary coil,
which can be selectively activated/deactivated by said controller
device in order to respectively allow/prevent the passage of
current through it to provide the transformer with an alternating
electric current.
5. The indication apparatus as in any of claim 1, wherein said
capacitor is connected to said battery by means of a resistor
having a resistance value such as to prevent the switching on of
said lighting device only by means of said battery.
6. The indication apparatus of claim 1, wherein said voltage
measurement circuit comprises an operational amplifier connectable
by means of the first connector and the second connector to the
positive and negative terminals of the thermocouple, and is
configured to calculate the difference in electric voltage between
the two terminals, and to supply said controller device with an
output signal correlated to the difference in electric voltage
calculated.
7. The indication apparatus of claim 1, wherein said controller
device is connected by means of a first circuit branch to said
battery and by means of a second circuit branch to said power
circuit, wherein said first branch and said second branch are
connected in a common node.
8. A gas appliance comprising a valve device configured to supply a
flow of gas to a main burner and to a pilot burner, and provided
with a pilot valve which can be driven manually with a manual drive
device by means of which a user can take it to an open condition to
allow the passage of the gas through it, and a electro valve
configured to keep it in the open condition when it is powered with
sufficient voltage, and with a thermocouple configured to convert
the heat supplied by a pilot flame of the pilot burner into an
electric voltage suitable to power the electro valve to keep the
pilot valve open, characterized in that said gas appliance
comprises the indication apparatus of claim 1 connected to the
terminals of said thermocouple.
9. A method to indicate the output level of a pilot flame in a gas
appliance provided with a thermocouple suitable to convert the
energy generated by a pilot flame, which receives gas from a pilot
valve, into an electric voltage suitable to power an electro valve
of the pilot valve and to keep the latter open, characterized in
that said method comprises: detecting an electric voltage at the
terminals of the thermocouple by means of a voltage measurement
circuit; calculating the difference in electric voltage between the
two terminals, and providing a controller device with an output
signal correlated to the difference in electric voltage calculated
in order to determine the electric voltage generated by the
thermocouple; comparing the electric voltage generated by the
thermocouple with predefined reference values and, when said
electric voltage is equal to or greater than a first predefined
value, insufficient to power the electro valve, accumulating in a
capacitor of a power circuit connected between said thermocouple
and said lighting device a quantity of electric charge, supplied by
said thermocouple, and suitable to switch on a lighting device;
keeping monitored said electric voltage generated by the
thermocouple and said quantity of electric charge accumulated in
the power circuit, wherein the method provides to: power said
voltage measurement circuit and said controller device by means of
a battery; command, by means of said controller device, said power
circuit in order to supply said lighting device with said quantity
of accumulated electric charge so that it flashes, when the
electric voltage generated by the thermocouple is greater than or
equal to a second predefined value, sufficient to power the electro
valve, and the quantity of electric charge accumulated is
sufficient to switch on said lighting device.
10. The method of claim 9, said method provides to accumulate said
electric charge in said capacitor by means of a transformer
connected between the thermocouple and the capacitor, wherein the
method provides to selectively activate and/or deactivate a first
switch connected in series to a primary coil of said transformer by
means of said controller device in order to respectively allow
and/or prevent the passage of current through it to provide the
transformer with an alternating electric current when the voltage
generated by the thermocouple is greater than or equal to the first
predefined value.
11. The method in of claim 10, wherein, in order to switch on the
lighting device (22) with said quantity of accumulated electric
charge, the method provides to activate a second switch, connected
in series to said lighting device, by means of said controller
device, to allow the electric charge accumulated in said capacitor
to discharge through said lighting device and switch on the
latter.
12. The method claim 10, wherein said method provides to pre-charge
said capacitor with a quantity of charge provided by said battery
at the moment said battery is installed.
13. The method of claim 9, further comprising powering said
controller device by means of the power circuit with the energy
supplied by said thermocouple, when, under normal working
conditions, the electric voltage of said power circuit is greater
than the electric voltage of said battery.
Description
FIELD OF THE INVENTION
[0001] The present invention concerns in general an apparatus to
indicate an output level of a pilot flame used in gas appliances
provided with manual valves and thermoelectric safety valve
devices. In particular, the gas appliances in question can comprise
boilers, storage water heaters, stoves, ovens, fireplaces, or
similar or comparable appliances, provided with a gas burner.
[0002] The invention also concerns the connected method to indicate
the output level of a pilot flame in a gas appliance.
BACKGROUND OF THE INVENTION
[0003] Gas heating appliances are known, for example boilers, or
water heaters, generally provided with a main burner and a pilot
burner. Normally, also for safety reasons, these gas appliances
have sealed combustion chambers, and are provided with a pilot
valve, manually drivable by a user, to supply a flow of gas to the
pilot burner.
[0004] The opening of the pilot valve allows to switch on the pilot
flame of the pilot burner by means of an ignition device, for
example a piezoelectric element. The pilot flame then powers a
thermocouple, which converts the heat into electric energy suitable
to power an electro valve that keeps the pilot valve open. The
pilot burner therefore remains switched on and burns continuously
to keep the pilot flame ignited to supply the ignition source for
the main burner.
[0005] The gas valves and pilot burners function independently of
any connection to the electric power inside the building in which
they are installed.
[0006] In gas appliances of this type it is normally difficult to
control the functioning of the pilot valve and the ignition device
since the pilot flame is positioned in places that are not easily
accessible to the user and is therefore difficult to see from
outside the gas appliance.
[0007] When the pilot flame is first ignited, or re-ignited
following a malfunctioning of the appliance, or a maintenance
operation, the user has to manually open the pilot valve, to supply
gas to the pilot burner, and subsequently drive the ignition device
to ignite the pilot flame, continuing to keep the valve open
manually until the thermocouple is able to generate an electric
voltage of sufficient value to keep the pilot valve open.
[0008] Since the pilot flame is not normally visible to the user,
the user cannot understand whether the pilot flame is correctly
ignited, or whether it is supplying sufficient energy to keep the
pilot valve open, so he does not know if/when he can release the
manual drive.
[0009] In order to at least partly solve this problem, indication
apparatuses are known, associated with the gas appliances, suitable
to provide an output level of the pilot flame to indicate to the
user when he can release the manual drive of the pilot valve.
[0010] For example, from U.S. Pat. No. 9,080,769 an apparatus is
known to indicate an output level of a pilot flame for heating
appliances, comprising a voltage measurement circuit which provides
an output indicative of a quantity of the voltage generated by the
thermocouple, a lighting device and a controller coupled with the
thermocouple and with the lighting device. The controller, based on
the output provided by the voltage measurement circuit, determines
a switching sequence to switch on and switch off the lighting
device with a defined frequency, and provides an indication of when
the voltage generated by the thermocouple is growing toward a value
sufficient to keep the pilot valve open. In the solution described
in U.S. Pat. No. 9,080,769 the controller and the lighting device
are both powered by a battery. This known solution has the
disadvantage that the battery, having to power the two components,
has a limited duration, so that it is not possible to continuously
maintain the flashing of the lighting device.
[0011] Another known solution, described for example in U.S. Pat.
No. 4,770,629, describes a control system for a burner provided
with a pilot flame which powers a thermoelectric generator, which
supplies energy to an oscillator. The oscillator has an output that
is increased to a voltage level and converted to a regulated direct
current potential, which is in turn used to operate a solid state
controller. The controller has a sampling frequency which is
visually indicated by a light-emitting diode when a suitable
electric voltage is present. This known solution has the
disadvantage that it entails an increase in the time required to
activate the electro valve due to the fact that part of the energy
supplied by the pilot flame is used to power the controller and the
emitter diode.
[0012] Document DE-A-199 17 488 describes an indication device for
a gas burner that provides to use the thermocouple as a sensor to
signal to a user the actual functioning state of the burner after
the initial start-up step.
[0013] Further indicator devices are known from JP-U-S56 18984 and
JP-A-S63 286619.
[0014] There is therefore a need to perfect and provide an
apparatus to indicate an output level of a pilot flame which
overcomes at least one of the disadvantages of the state of the
art.
[0015] One purpose of the present invention is to provide an
apparatus to indicate an output level of a pilot flame which does
not entail an extension of the time required to power the electro
valve with a sufficient electric voltage and which, at the same
time, can provide the user with a reliable and immediate signal of
when the manual drive can be released.
[0016] A further purpose of the invention is to provide an
apparatus to indicate the output level of the pilot flame that
allows to increase the life of a battery without the need to
provide downtimes of the apparatus.
[0017] The Applicant has devised, tested and embodied the present
invention to overcome the shortcomings of the state of the art and
to obtain these and other purposes and advantages.
SUMMARY OF THE INVENTION
[0018] The present invention is set forth and characterized in the
independent claims, while the dependent claims describe other
characteristics of the invention or variants to the main inventive
idea.
[0019] Embodiments described here concern an indication apparatus
to indicate the output level of a pilot flame in a gas appliance,
which is provided with a thermocouple suitable to convert the
energy generated by a pilot flame, which receives gas from a pilot
valve, into an electric voltage suitable to power an electro valve
of the pilot valve in order to keep the latter open. The indication
apparatus comprises:
[0020] a first and a second connector suitable to be coupled with a
positive terminal and with a negative terminal of the
thermocouple;
[0021] a voltage measurement circuit connected to the first and
second connector and configured to calculate the difference in
electric voltage at the heads of the terminals so as to determine
the electric voltage generated by the thermocouple, and provide an
output correlated to the difference in voltage calculated;
[0022] a lighting device configured to provide a light signal;
[0023] a controller device, coupled with the voltage measurement
circuit and with the lighting device, and configured to determine
the switching on of the lighting device on the basis of the output
supplied by the voltage measurement circuit to provide a user with
an indication of when the voltage generated by the thermocouple is
greater than or equal to a predefined value, sufficient to power
the electro valve, that is, such that a user can stop keeping the
pilot valve open manually;
[0024] a battery, connected to the controller device, and suitable
to power the latter and the voltage measurement circuit, and
[0025] a power circuit, connected between the connectors and the
lighting device, and configured to supply the latter with the
electric voltage supplied by the thermocouple on the basis of
commands received from the controller device, in such a way as to
switch on the lighting device in a flashing manner when the voltage
generated by the thermocouple is greater than or equal to the
predefined value.
[0026] When the lighting device is switched on, therefore, the user
can release the manual drive of the pilot valve, which is kept open
by the electro valve powered by the thermocouple.
[0027] In the indication apparatus according to the invention,
therefore, a part of the components is powered by a specific
battery, in this case the voltage measurement circuit and the
controller device, while another part of the components, in this
case the lighting device, is powered by the thermocouple.
[0028] This particular configuration allows to obtain at least the
following advantages:
[0029] the life of the battery is increased, therefore requiring
few, or no, interventions to replace it throughout the life span of
the indication apparatus;
[0030] it is possible to keep the lighting device switched on in a
flashing manner continuously without needing to provide for
temporary deactivation intervals of the indication apparatus;
[0031] the level of electric voltage sufficient to keep the electro
valve open is reached more quickly, as the controller device is
powered only by the battery;
[0032] it is possible to quickly provide the user with an
indication of when the electric voltage supplied by the
thermocouple is sufficient to keep the electro valve open
autonomously.
[0033] According to some embodiments, the power circuit comprises a
capacitor connected to the lighting device and configured to
accumulate a quantity of electric charge supplied by the
thermocouple sufficient at least to allow the switching on of the
lighting device.
[0034] According to further embodiments, the power circuit
comprises a second switch connected in series to the lighting
device, which can be selectively activated and/or deactivated by
the controller device in order to respectively allow and/or prevent
the electric charge accumulated in the capacitor being discharged
through the lighting device.
[0035] At the end of the charge transient of the thermocouple, as
long as the pilot flame remains ignited, the lighting device can
continue to flash with a frequency correlated to the
charging/discharging time of the capacitor, to indicate the correct
functioning of the gas appliance, without consuming the battery.
Embodiments described here also concern a gas appliance, provided
with a thermocouple suitable to convert the energy generated by a
pilot flame, which receives gas from a pilot valve, into electric
voltage to power an electric valve of the pilot valve and to keep
the latter open in order to allow a pilot flame in a pilot burner
to be powered, and with an indication apparatus according to the
invention connected with the thermocouple.
[0036] A purpose of the present invention is also a method to
indicate the output level of a pilot flame in a gas appliance
provided with a thermocouple suitable to convert the energy
generated by a pilot flame, which receives gas from a pilot valve,
into electric voltage to power an electro valve of the pilot valve
and to keep the latter open, wherein the method comprises:
[0037] detecting an electric voltage at the terminals of the
thermocouple by means of a voltage measurement circuit;
[0038] calculating the difference in electric voltage between the
two terminals, and providing a controller device with an output
signal correlated to the difference in electric voltage calculated
in order to determine the electric voltage generated by the
thermocouple;
[0039] comparing the electric voltage generated by the thermocouple
with predefined reference values and, when the electric voltage
generated by the thermocouple is equal to or greater than a first
predefined value, insufficient to power the electro valve,
accumulating in a power circuit a quantity of electric charge,
supplied by the thermocouple, suitable to switch on a lighting
device;
[0040] keeping monitored the electric voltage generated by the
thermocouple and the quantity of electric charge accumulated in the
power circuit, wherein the method provides to:
[0041] power the voltage measurement circuit and the controller
device by means of a battery;
[0042] command the power circuit, by means of the controller
device, in order to supply the lighting device with the quantity of
accumulated electric charge so that it flashes when the electric
voltage generated by the thermocouple exceeds a second predefined
value, sufficient to power the electro valve, and the quantity of
electric charge accumulated is sufficient to switch on the lighting
device.
BRIEF DESCRIPTION OF THE DRAWINGS
[0043] These and other characteristics of the present invention
will become apparent from the following description of some
embodiments, given as a non-restrictive example, with reference to
the attached drawings wherein:
[0044] FIG. 1 is a schematic view of a gas appliance provided with
an apparatus to indicate the output level of the pilot flame
according to embodiments described here;
[0045] FIG. 2 is a schematic diagram of an apparatus to indicate
the output level of the pilot flame according to embodiments
described here;
[0046] FIG. 3 is a schematic diagram of an apparatus to indicate
the output level of the pilot flame according to variant
embodiments described here;
[0047] FIG. 4 is a schematic diagram of an apparatus to indicate
the output level of the pilot flame according to further variant
embodiments described here.
[0048] To facilitate comprehension, the same reference numbers have
been used, where possible, to identify identical common elements in
the drawings. It is understood that elements and characteristics of
one embodiment can conveniently be incorporated into other
embodiments without further clarifications.
DETAILED DESCRIPTION OF SOME EMBODIMENTS
[0049] Embodiments described here with reference to the drawings
concern an apparatus 10 to indicate the output level of a pilot
flame in a gas appliance 11.
[0050] Examples of gas appliances 11 of the type in question can
comprise boilers, storage water heaters, stoves, ovens, fireplaces
or similar or comparable appliances.
[0051] With reference to FIG. 1, the gas appliance 11 comprises a
valve device 12 configured to supply a flow of gas coming from a
source of gas respectively to a main burner 13 and to a pilot
burner 14.
[0052] The valve device 12 comprises a pilot valve 15 which, in an
open condition, allows the passage of a gas flow toward the pilot
burner 14.
[0053] The valve device 12 also comprises a main valve, not shown,
which allows the passage of a flow of gas toward the main burner
13.
[0054] The pilot valve 15 is provided with a manual drive device 16
by means of which a user can take it into an open condition in
which the gas can flow through it, and with an electro valve 17
configured to keep it in the open condition when it is powered with
a sufficient voltage. The electro valve 17 can comprise, for
example, a magnetic unit, or a solenoid coil which generates a
magnetic field suitable to keep the pilot valve 15 open.
[0055] The gas appliance 11 also comprises an ignition device 18,
for example a piezoelectric device, which can be pressed or
activated by the user to ignite a pilot flame in the pilot burner
14 while the pilot valve 15 is kept open by means of the manual
drive device 16 driven by the user.
[0056] The valve device 12 also comprises a thermocouple 19,
configured to convert the heat provided by the pilot flame into
electric voltage, which, upon reaching a sufficient value, can be
applied to the electro valve 17 to keep the pilot valve 15
open.
[0057] The apparatus 10 to indicate the output level of the pilot
flame can be connected with, or integrated, in the gas appliance
11. For example, it can be provided that the indication apparatus
10 is made integrated in a gas appliance 11 directly during the
step of making the latter, or that it is made as a separate
component, connectable to newly made or already existing gas
appliances 11.
[0058] According to some embodiments, the indication apparatus 10
is configured to receive at input information on the value of the
voltage generated by the thermocouple 19 and to provide the user
with an indication correlated to the voltage value received, in
particular to indicate to the user when he can release the manual
drive 16.
[0059] The indication apparatus 10 (FIG. 2) can comprise a first
connector 20a and a second connector 20b configured to be connected
respectively to a first terminal T1 and a second terminal T2 of the
thermocouple 19, for example the positive terminal and the negative
terminal respectively.
[0060] According to embodiments described with reference to FIG. 2,
the indication apparatus 10 comprises a voltage measurement circuit
21 configured to measure the electric voltage generated by the
thermocouple 19 and supply an output correlated to the value of the
electric voltage measured.
[0061] The indication apparatus 10 also comprises a lighting
device, for example a LED (Light Emitting Diode) 22, and a
controller device 23 coupled with the voltage measurement circuit
21 and the LED 22.
[0062] The controller device 23 is configured to control the
switching on of the LED 22 on the basis of the output supplied by
the voltage measurement circuit 21.
[0063] According to some embodiments, the indication apparatus 10
also comprises a battery 24 connected to the controller device 23
and configured to power the controller device 23 and the voltage
measurement circuit 21 with the electric energy necessary for their
functioning.
[0064] According to some embodiments, the voltage measuring circuit
21 and the controller device 23 can be made on the same electronic
board, not shown, which is connected and powered by the battery
24.
[0065] According to some embodiments, the voltage measurement
circuit 21 is powered by the electric energy supplied by the
battery 24 by means of an output Out3 of the controlling device
23.
[0066] The thermocouple 19, therefore, at least in an initial
transitional heating step, does not power either the voltage
measurement circuit 21 or the controller device 23. These therefore
do not risk interrupting or influencing in any way the electric
voltage generated by the thermocouple 19.
[0067] Furthermore, the battery 24 does not power any component of
the valve device 12, which therefore functions independently of the
state of charge of the battery 24.
[0068] According to one aspect of the present invention, the
indication apparatus 10 comprises a power circuit 25 coupled with
the thermocouple 19 and the LED 22 and configured to power the
latter with the electric voltage supplied by the thermocouple
19.
[0069] According to some embodiments, the voltage measurement
circuit 21 comprises an operational amplifier 26, which acts as a
comparator to calculate the difference between two values of
electric voltage. The operational amplifier 26 is connected, by
means of the first connector 20a and the second connector 20b, to
the positive T1 and negative T2 terminals of the thermocouple 19,
and is configured to calculate the difference in electric voltage
between the two terminals T1, T2, and supply an output signal
correlated to the difference in electric voltage calculated.
[0070] According to possible embodiments, the non-inverting input
27 of the operational amplifier 26, during use, is connected to the
positive terminal T1, while the inverting input 28 is connected, by
means of one or more resistances R, to the negative terminal T2, in
this example case with a common connection to earth.
[0071] According to some embodiments, the operational amplifier 26
is connected, by means of its own output 29, to the controller
device 23 to supply the latter with the output signal correlated to
the difference in electric voltage calculated.
[0072] According to some embodiments, the controller device 23 can
be a microcontroller, a microprocessor, or other similar device
suitable to receive input signals/data, process them and provide
output signals/data correlated to the input signals/data.
[0073] According to some embodiments, a program, or a sequence of
instructions, can be stored in the controller device 23 to control
the power circuit 25 and determine the switching on of the LED 22
based on the input signals/data received.
[0074] According to some embodiments, the power circuit 25
comprises a transformer 30 provided with a primary coil 31 and a
secondary coil 32, and configured to raise the voltage generated by
the thermocouple 19.
[0075] According to some embodiments, the ratio between the primary
coil 31 and the secondary coil 32 is 1:n, where n can be comprised
between about 50 and about 150.
[0076] The primary coil 31 is connected to the terminals T1, T2 of
the thermocouple 19, while the secondary coil 32 is connected to
the clips of the LED 22.
[0077] According to some embodiments, the power circuit 25
comprises a capacitor 33 configured to accumulate the electric
energy supplied by the thermocouple 19.
[0078] In particular, the capacitor 33 is configured to accumulate
a quantity of electric charge at least sufficient to allow to
switch on the lighting device 22.
[0079] According to some embodiments, the capacitor 33 is connected
in parallel between the secondary coil 32 and the LED 22, and is
configured to accumulate the electric energy supplied by the
thermocouple 19 and raised by the transformer 30.
[0080] According to some embodiments, the secondary coil 32, the
capacitor 33 and the LED 22 can have a common connection to
earth.
[0081] According to some embodiments, the capacitor 33 is also
connected to the controller device 23 by means of an input In1 of
its own, so that the latter can monitor the electric voltage at the
heads of the capacitor 33 and therefore the quantity of charge
accumulated therein.
[0082] According to some embodiments, the power circuit 25
comprises a first switch 34 connected in series to the primary coil
31, which can be selectively activated/deactivated by the
controller device 23 to respectively allow/prevent the passage of
current through it and supply the transformer 30 with an alternate
electric current.
[0083] In particular, when the first switch 34 is active, it allows
the passage of an electric current through the primary coil 31,
while when it is inactive it behaves like an open circuit,
preventing the passage of the electric current.
[0084] The power circuit 25 can further comprise a second capacitor
35, connected in parallel between the thermocouple 19 and the
primary coil 31 and configured to accumulate electric energy when
the first switch 34 is inactive.
[0085] According to some embodiments, the power circuit 25 further
comprises a second switch 36 connected in series with the LED 22,
which can be selectively activated/deactivated by the controller
device 23 to respectively allow/prevent the electric energy
accumulated in the capacitor 33 being discharged through the LED
22.
[0086] In particular, when the second switch 36 is active it allows
the passage of an electric current through the LED 22, so as to
switch on the latter, while when it is inactive it behaves like an
open circuit, and prevents the passage of an electric current.
[0087] According to some embodiments, the first switch 34 and/or
the second switch 36 can be, for example, semiconductor transistor
devices, for example of the MOSFET (Metal Oxide Semiconductor
Field-Effect Transistor) type, or other similar devices.
[0088] According to further embodiments, in the power circuit 25
there is also a diode D connected between the secondary coil 32 and
the LED 22 and configured to straighten the electric current at
output from the secondary coil 32 toward the capacitor 33 and the
LED 22.
[0089] The functioning of the indication apparatus 10 at the moment
of ignition of the pilot flame is described below.
[0090] The controller 23 performs a detection of the electric
voltage generated by the thermocouple 19 at intervals with a
defined sampling frequency.
[0091] According to some embodiments, the sampling frequency can be
fixed or vary according to the conditions.
[0092] For example, the controller device 23 can be configured to
detect the electric voltage with a first frequency when the pilot
flame is off or the electric voltage Vt generated by the
thermocouple 19 is lower than a first predefined value Voff,
insufficient to keep the electro valve 17 open.
[0093] The first frequency can be, for example, 0.3 Hz.
[0094] The controller device 23 can be configured to detect the
electric voltage with a second frequency when the pilot flame is
on, or when the electric voltage Vt generated by the thermocouple
19 is greater than or equal to a second predefined value Von,
sufficient to keep the electro valve 17 open.
[0095] The second frequency can be lower than the first frequency,
for example 0.1 Hz.
[0096] When the controller device 23 detects that the electric
voltage Vt generated by the thermocouple 19 is higher than a first
threshold value V1, it commands the first switch 34 by means of a
first output Out1 to activate/deactivate it in a controlled
manner.
[0097] In this way, the transformer 30 is powered, which raises the
voltage generated by the thermocouple 19 which is accumulated in
the capacitor 33 disposed downstream.
[0098] During the charge transient of the thermocouple 19, the
second switch 36 is in an inactive state, therefore no electric
current flows through it and all the energy is accumulated in the
capacitor 33.
[0099] According to some embodiments, the controller device 23 can
command the first switch 34 by means of a PWM (Pulse Width
Modulation) command with a desired duty cycle.
[0100] Furthermore, the controller device 23 keeps the electric
voltage at the heads of the capacitor 33 monitored by means of the
first input In1.
[0101] When the electric voltage Vt generated by the thermocouple
19 exceeds the second predefined value Von, that is, it is
sufficient to keep the electro valve 17 open, and the quantity of
electric charge stored in the capacitor 33 is equal to or greater
than a predefined threshold value C*, sufficient to allow the
switching on of the LED 22, then the controller 23 activates the
second switch 36 by means of a second output Out2.
[0102] In this way, the circuit branch of the LED 22 is earthed,
and the charge stored in the capacitor 33 can be discharged through
the LED 22, which switches on with a single flash.
[0103] When the LED 22 is switched on, the user can release the
manual drive device 16 and the pilot valve 15 is kept in the open
state by the electro valve 17.
[0104] Once the capacitor 33 is discharged, the second switch 36 is
deactivated again to allow a new accumulation of electric charge in
the capacitor 33.
[0105] Following the transitional step of starting and igniting the
pilot flame, the LED 22 can continue to flash with a frequency
correlated to the charge/discharge speed of the capacitor 33.
[0106] By way of example, the frequency can be about 0.5 Hz, that
is, one flash approximately every 2 seconds.
[0107] In fact, as long as the electric voltage Vt generated by the
thermocouple 19 remains higher than the first threshold value V1,
the controller device 23 continues to activate/deactivate the first
switch 34 to charge the capacitor 33 and, when the accumulated
electric charge reaches the predefined threshold value C*, it
commands the activation of the second switch 36.
[0108] According to further embodiments, described with reference
to FIG. 3, the power circuit 25 can be connected to the battery
24.
[0109] According to these solutions, the power circuit 25 can
comprise a resistor 37 connected between the battery 24 and the
capacitor 33.
[0110] In this case, the capacitor 33 can be pre-charged directly
by the battery 24 when it is installed, therefore the execution of
the first flash of the LED can occur as soon as the controller
device verifies that the electric voltage Vt is equal to or greater
than the second predefined value Von, without needing to wait for a
charge transient of the capacitor 33 with the electric energy
supplied by the thermocouple 19.
[0111] According to some embodiments, the resistance value of the
resistor 37 can be defined in the design step so as to satisfy the
following requirements:
[0112] it must be high enough to prevent the LED 22 from switching
on by means of the battery 24;
[0113] it must be low enough to allow the capacitor 33 to charge in
a limited period of time after the battery 24 has been
installed.
[0114] By way of example, this period of time can be comprised
between a few seconds and a few minutes, for example less than five
minutes.
[0115] According to this variant embodiment, therefore, the energy
required for the first switching on of the LED 22 at the end of the
charge transient of the thermocouple 19 is supplied to the power
circuit 25 by the battery 24.
[0116] Subsequently, once normal working conditions have been
reached, as long as the pilot flame remains on, the energy required
to switch on the LED 22 is supplied almost completely by the
thermocouple 19 by means of the transformer 30 and the capacitor
33, since the energy transfer from the battery 24 is limited by the
resistor 37.
[0117] Furthermore, when the pilot flame is switched off, the
lighting device stops flashing, and the power circuit 25 only takes
from the battery 24 the energy necessary for the charge transient
of the capacitor 33, since the diode D on one side and the second
switch 36 on the other prevent the passage of the electric current
to the earth.
[0118] It is clear that modifications and/or additions of parts may
be made to the apparatus 10 and method to indicate the output level
of a pilot flame as described heretofore, without departing from
the field and scope of the present invention.
[0119] For example, according to a further embodiment described
with reference to FIG. 4, it can be provided that the controller
device 23 is also connected, in addition to the battery 24, to the
power circuit 25.
[0120] According to these embodiments, the controller device 23 can
be provided with two distinct power branches, of which a first
branch 38 is connected to the battery 24, and a second branch 39 is
connected to the power circuit 25, and in particular to the
secondary coil 32.
[0121] According to some embodiments, the two branches 38, 39 are
connected in a common node 45, so that the controller device 23 is
powered by the branch 38, 39 which on each occasion has the
greatest electric voltage.
[0122] According to some embodiments, a capacitor 42 can be present
between the common node 45 and the earth, having the function of a
filter and configured to stabilize the electric voltage supplied to
the controller 23.
[0123] During the initial transitional step of heating the
thermocouple 19, the electric voltage supplied by the power circuit
25 is lower than the electric voltage supplied by the battery 24,
therefore the controller device 23 is powered by the latter by
means of the first branch 38.
[0124] During the functioning under normal working conditions, when
the thermocouple 19 has heated up, the electric voltage at the
heads of the secondary coil 32 of the power circuit 25 is generally
greater than that supplied by the battery 24, therefore the
controller device 23 is powered by the power circuit 25 by means of
the second branch 39.
[0125] This embodiment allows to further increase the duration of
the battery 24, since, under normal working conditions, when the
pilot flame is ignited, the entire apparatus 10 is powered only by
the thermocouple 19.
[0126] In the event that the pilot flame goes out, and/or the
electric voltage of the second branch 39 in the common node 45
falls below the electric voltage of the battery 24, the functioning
of the controlling device 23 is in any case guaranteed by the
battery 24.
[0127] According to some embodiments, the first branch 38 and the
second branch 39 comprise respective diodes 40, 41 which perform a
protective function. In particular, the diode 40 in the first
branch 38 prevents the electric voltage supplied by the power
circuit 25 from damaging the battery 24, while the diode 41 in the
second branch 39 prevents the electric energy supplied by the
battery 24 from flowing in the form of electric current toward the
power circuit 25 and toward the LED.
[0128] According to some embodiments, the apparatus 10 comprises a
voltage limiting circuit 46 connected between the controller device
23 and the common node 45 and configured to limit the voltage at
input to the controller device 23 so as to prevent possible damage
to the latter.
[0129] According to possible embodiments, the voltage limiting
circuit 46 can comprise a resistor 43 and a third switch 44, which
can be selectively activated by the controller device 23, disposed
in series one after the other.
[0130] According to some embodiments, the third switch 44 can be
activated by the controller device 23 by means of an output Out4 of
its own, when it detects that the electric voltage at the input Vcc
exceeds a predetermined voltage value, so as to allow the passage
of an electric current through the resistor 43 to the earth, thus
reducing the electric voltage at input to the controller device
23.
[0131] It is also clear that, although the present invention has
been described with reference to some specific examples, a person
of skill in the art shall certainly be able to achieve many other
equivalent forms of apparatus 10 and method to indicate the output
level of a pilot flame, having the characteristics as set forth in
the claims and hence all coming within the field of protection
defined thereby.
* * * * *