BURNER COMPRISING A CONTROL UNIT AND AN IGNITION AND IONIZATION ELECTRODE AND METHOD OF MONITORING AND IGNITING THE FLAME OF A BURNER

Abstract

Example embodiments relate to a burner including a control unit and an ignition and ionization electrode for igniting and monitoring the burner flame, wherein the ignition and ionization electrode is arranged in the flame area of the burner, is electrically coupled to a discharge circuit and provides an ionization signal when the flame of the burner is switched on, wherein the control unit provides an output signal for actuating the burner on the basis of the ionization signal, and wherein the discharge circuit is connected to a DC voltage source. Example embodiments further relate to a method of monitoring and igniting the flame of a burner and to a circuit arrangement for a burner.

Claims

1. A burner comprising: a control unit and an ignition and ionization electrode for igniting and monitoring the burner flame, wherein the ignition and ionization electrode is arranged in the flame area of the burner, is electrically coupled to a discharge circuit and provides an ionization signal when the flame of the burner is switched on, wherein the control unit provides an output signal for actuating the burner on the basis of the ionization signal, and wherein the discharge circuit is connected to a DC voltage source.

2. The burner according to claim 1, wherein the supply voltage provided by the DC voltage source is between 8 and 50 V.

3. The burner according to claim 1, wherein a voltage transformer is provided by means of which the control unit varies the supply voltage of the DC voltage source before the discharge circuit is supplied therewith.

4. The burner according to claim 1, wherein the voltage transformer varies the voltage of the DC voltage source between 100 and 300 V.

5. The burner according to claim 1, wherein the DC voltage source is a battery or an accumulator.

6. The burner according to claim 1, wherein the discharge energy of the discharge circuit can be adjusted by the control unit by means of frequency change of a pulse width modulation.

7. The burner according to claim 1, wherein the discharge circuit comprises a capacitor and/or an ignition transformer.

8. The burner according to claim 1, wherein an operational amplifier is provided which amplifies the ionization signal which is present when the burner flame is switched on.

9. A circuit arrangement comprising: a control unit and an ignition and ionization electrode for igniting and monitoring the burner flame of a burner, wherein the ignition and ionization electrode is arranged in the flame area of the burner, is electrically coupled to a discharge circuit and provides an ionization signal when the flame of the burner is switched on, wherein the control unit provides an output signal for actuating the burner on the basis of the ionization signal, and wherein the discharge circuit is connected to a DC voltage source.

10. A method of monitoring and igniting a flame of a burner, the method comprising: a) providing, by a DC voltage source, a discharge circuit, b) igniting, by a control unit, a flame which releases a fuel supply in the burner and causes a discharge of the discharge circuit via an ignition and ionization electrode, c) an ionization signal generated generating, by an ignition and ionization electrode, an ionization signal, and amplified is detected and monitored by the control unit, d) outputting, by the control unit, an output signal on the basis of the amplified ionization signal as a function of which a gas and/or air supply of the burner is controlled.

11. The method according to claim 10, wherein the supply voltage of the DC voltage source in step a) is varied by the control unit using a voltage transformer as a function of one or more of the following influencing factors: the burner, the burner temperature and the degree of contamination or the deposits on the ignition and ionization electrode which can be estimated on the basis of the service life or the resistance of a protective circuit.

12. The method according to claim 10, characterized in that wherein the discharge energy upon ignition of the flame in step b) is varied by the control unit as a function of the ambient temperature and/or the air humidity.

13. The method according to claim 10, wherein as soon as the control unit detects in step d) that the amplified ionization signal is below a predetermined limit value, the fuel supply is stopped, or after a further discharge of the discharge circuit, it is checked whether an ionization signal above the limit value is detected by the control unit.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0028] The present disclosure is described below with reference to an embodiment which is represented in the accompanying drawing and in which:

[0029] FIG. 1 schematically shows a burner comprising an assembly for igniting and monitoring the burner flame.

DETAILED DESCRIPTION

[0030] FIG. 1 shows a burner comprising a burner nozzle 10 and an ignition and ionization electrode 20.

[0031] The burner serves to heat air and/or water and can be installed in mobile homes and caravans, for example.

[0032] The ignition and ionization electrode 20 is arranged in the flame area of the burner nozzle 10 and generates an ionization signal when the flame is switched on, which is transmitted to a control unit 40 via a protective circuit 22 and an operational amplifier 30. The ignition and ionization electrode 20 and the protective circuit 22 are electrically coupled to a discharge circuit 50.

[0033] The discharge circuit 50 comprises a capacitor 52 and an ignition transformer 54.

[0034] The discharge circuit 50 and the protective circuit 22 are supplied by a supply voltage of a DC voltage source 70 converted by a voltage transformer 60.

[0035] The supply voltage of the DC voltage source 70 can be between 8 and 50 V. It is conceivable to use a battery 72 or an accumulator 74 as a DC voltage source 70. Alternatively, it is possible to use a power supply unit.

[0036] In the illustrated embodiment, the supply voltage of the DC voltage source 70 is variably converted by the control unit 40 by means of the voltage transformer 60. This can be done by pulse width modulation, the frequency of which is in the range of a few kHz to 1 MHz. It is then conceivable that the voltage can be varied between 100 to 300 V, but is usually 180 V.

[0037] Varying the supply voltage of the DC voltage source 70 by means of the voltage transformer 60 can be carried out depending on different influencing factors such as the burner type, the burner temperature and the degree of contamination or the deposits on the ignition and ionization electrode 20. The degree of contamination and the deposits on the electrode are estimated on the basis of the service life and on the basis of the resistance present in the protective circuit 22.

[0038] It is also conceivable to introduce a voltage divider and a low-pass filter to be able to measure the voltage converted by the voltage transformer 60 by means of the control unit 40.

[0039] In addition, the control unit 40 can comprise a proportional-integral-derivative controller or a proportional-integral controller by means of which the converted voltage can be adjusted to a set value.

[0040] To ignite the burner flame, the control unit 40 releases the fuel supply so that the fuel-air mixture flows out at the burner nozzle 10. Simultaneously, ignition takes place by a discharge of the discharge circuit 50 via the ignition and ionization electrode 20.

[0041] The discharge energy of the discharge circuit 50 released upon ignition can be adjusted variably by the control unit 40. The discharge energy can be varied by changing the number of discharges per second. Typically, the discharge frequency is in the range from 8 to 50 Hz.

[0042] In this configuration, it is conceivable to control the discharge energy of the discharge circuit 50 by means of the control unit 40 as a function of external influencing factors such as the ambient temperature and/or the air temperature.

[0043] When the burner flame burns, an ionization signal is generated at the ignition and ionization electrode 20. At the same time, the converted supply voltage of the DC voltage source 70 is applied to the protective circuit 22 as an external voltage. The operational amplifier 30 amplifies the DC voltage component of the ionization signal which is present at the ignition and ionization electrode 20 due to the rectifier property of the flame.

[0044] The control unit 40 detects the amplified ionization signal which is present at the burner nozzle 10 due to the burner flame, and outputs an output signal depending on the ionization signal, which controls the gas supply to the burner nozzle 10. If there is no ionization signal at the control unit 40 or an ionization signal the value of which is below a predetermined limit value when the fuel supply is released, the control unit 40 stops the further fuel supply. This prevents further fuel from flowing out of the burner nozzle which would then not be burned.

[0045] According to an alternative, the control unit 40 reactivates the discharge circuit 50 when the ionization signal falls below a predetermined limit value. In case a stable flame is then generated again at the burner nozzle 10, an ionization signal is again applied to the control unit 40, and the burner can continue to be operated. In case no ionization signal is detected after an ignition attempt, the control unit 40 stops the further supply of fuel.

[0046] While the disclosure has been described with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the disclosure. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the disclosure without departing from the essential scope thereof. While various aspects and embodiments have been disclosed herein, other aspects and embodiments will be apparent to those skilled in the art. The various aspects and embodiments disclosed herein are for purposes of illustration and are not intended to be limiting, with the true scope and spirit being indicated by the following claims.