DE3143730C1

DE3143730C1 - Device for switching on and off as required the main burner of a gas burner

Info

Publication number: DE3143730C1
Application number: DE3143730A
Authority: DE
Inventors: Friedrich 7135 Wiernsheim Obermeier
Original assignee: WIELAND FA DR TH
Current assignee: WIELAND FA DR TH
Priority date: 1981-11-04
Filing date: 1981-11-04
Publication date: 1983-02-03

Abstract

In a device for switching on and off as required the main burner of a gas burner with constantly switched-on pilot burner, it is envisaged to bring about the switching on and off by emitting an infrared signal in the appliance, which is at least partially backscattered, by the hand operating the appliance, into an infrared receiver which, when the signal intensity is adequate, opens the solenoid valve of the main burner or, in the absence of reflection, closes the solenoid valve again. This arrangement guarantees actuation of the solenoid valve exclusively to the hand operating the appliance and eliminates environmental influences, which is not possible to this extent in the case of optical appliances operating with existing light.

Description

Ein Ausführungsbeispiel der erfindungsgemäßen Einrichtung wird nun anhand von Zeichnungen näher erläutert. Es zeigt F i g. 1 ein Blockschaltbild der erfindungsgemäßen Einrichtung, Fig.2 ein Detail-Schaltbild der erfindungsgemäßen Einrichtung gemäß Fig. 1. An embodiment of the device according to the invention will now be explained in more detail with reference to drawings. It shows F i g. 1 is a block diagram of the device according to the invention, FIG. 2 a detailed circuit diagram of the inventive device Device according to FIG. 1.

Die wesentlichen Bestandteile der erfindungsgemaßen Einrichtung (Fig. 1) bestehen aus einem Infrarotsender 10 und einem Infrarotempfänger 20, der das Magnetventil 28 öffnet und schließt Ein Netzteil 40 dient über Versorgungsleitungen VL zur Spannungsversorgung der einzelnen Komponenten. The essential components of the device according to the invention (Fig. 1) consist of an infrared transmitter 10 and an infrared receiver 20, the Solenoid valve 28 opens and closes. A power pack 40 is used via supply lines VL for supplying power to the individual components.

Diese Komponenten bestehen im Infrarotsender 10 im wesentlichen aus einer Sendediode 14 für Infrarotlicht und einem diese Sendediode 14 steuernden Oszillator OSZ, im Infrarotempfänger 20 aus einer Empfängerdiode 21 für infrarotes Licht, deren Ausgangssignal von einem Verstärker V ausreichend verstärkt wird, einem Integrierglied IG zugeführt wird und dann eine Schaltstufe S steuert, die schließlich das Magnetventil 28 öffnet oder schließt. These components consist essentially of in the infrared transmitter 10 a transmitting diode 14 for infrared light and an oscillator controlling this transmitting diode 14 OSZ, in the infrared receiver 20 from a receiver diode 21 for infrared light, whose Output signal is sufficiently amplified by an amplifier V, an integrator IG is supplied and then controls a switching stage S, which finally controls the solenoid valve 28 opens or closes.

Die Infrarotstrahlung der Sendediode 14 wird von der schematisch dargestellten Arbeitshand 50 zumindest teilweise in die Empfängerdiode 21 reflektiert und löst dort den Schaltvorgang aus. Solange ein vorherbestimmter Teil der Leistung der Sendediode 14 in die Empfängerdiode 21 gestreut wird, bleibt das Magnetventil 28 geöffnet, wird die Reflexion durch Wegnahme der Arbeitshand 50 unterbrochen, spricht die Schaltstufe San und das Magnetventil 28 schließt. The infrared radiation of the transmitting diode 14 is shown schematically by the shown working hand 50 is at least partially reflected in the receiver diode 21 and triggers the switching process there. As long as a predetermined part of the service the transmitting diode 14 is scattered in the receiving diode 21, the solenoid valve remains 28 opened, the reflection is interrupted by removing the working hand 50, speaks the switching stage San and the solenoid valve 28 closes.

Die Schaltung im einzelnen ist wie folgt aufgebaut (Fig. 2): Der Infrarotsender 10 beinhaltet den Oszillator OSZ (F i g. 1), der aus einem als Schmitt-Trigger geschalteten NAND-Gatter 11 besteht. Der Ausgang dieses Schmitt-Triggers ist über einen Inverter 12 mit der Basis eines Schalt-Transistors 13 verbunden, der im Stromweg der Sendediode 14 liegt Die Funktion des Infrarotsenders 10 ist wie folgt: Liegt keine Versorgungsspannung an, so befindet sich der Eingang 1 des NAND-Gatters 11 im Zustand L (LOW), folglich befindet sich dessen invertierender Ausgang 3 im Zustand H (HIGH), dementsprechend findet sich am Ausgang des Inverters 12 wieder der Zustand L. An der Basis des Schalttransistors 13 liegt daher kein Signal, und der Transistor 13 sperrt den Stromweg der Sendediode 14. The circuit in detail is constructed as follows (Fig. 2): The Infrared transmitter 10 includes the oscillator OSZ (FIG. 1), which consists of a Schmitt trigger switched NAND gate 11 consists. The output of this Schmitt trigger is over an inverter 12 connected to the base of a switching transistor 13 which is in the current path the transmitter diode 14 lies The function of the infrared transmitter 10 is as follows: lies If there is no supply voltage, input 1 of NAND gate 11 is located in state L (LOW), consequently its inverting output 3 is in state H (HIGH), accordingly the state is found again at the output of the inverter 12 L. There is therefore no signal at the base of the switching transistor 13, and so is the transistor 13 blocks the current path of the transmitter diode 14.

Wird nun vom Netzteil 40 die Versorgungsspannung von 9 V am Eingang 1 des NAND-Gatters 11 angelegt, so wird über einen Widerstand 60 ein Kondensator 15 aufgeladen, bis die Kippschwelle des NAND-Gatters an dessen Eingang 2 erreicht ist (die Bedingung also erfüllt ist), das NAND-Gatter schaltet um und sein Ausgang nimmt den Zustand L an. Folglich liegt am Ausgang 4 des Inverters 12 der Zustand Diese Spannung steuert den Schalttransistor 13 durch und schließt somit den Stromweg für die Sendediode 14, die dann ihre Infrarot-Strahlung abgeben kann. The supply voltage of 9 V at the input is now supplied by the power supply unit 40 1 of the NAND gate 11 is applied, a capacitor 60 is then applied via a resistor 60 15 charged until the breakover threshold of the NAND gate at its input 2 is reached is (the condition is fulfilled), the NAND gate switches and its output assumes the state L. As a result, the state is present at output 4 of inverter 12 This voltage controls the switching transistor 13 and thus closes the current path for the transmitter diode 14, which can then emit its infrared radiation.

Inzwischen hat sich der Kondensator 15 entladen, bis sein am Eingang 2 des NAND-Gatters 11 liegendes Ausgangspotential die untere Kippschwelle des NAND-Gatters erreicht hat Dieses schaltet folglich wieder in den Zustand H zurück und über den Inverter 12 sperrt der Schalttransistor 13 wieder. Darauf beginnt der Zyklus von vorne, so daß, abhängig von der Zeitkonstante r = R. C des Widerstandes 60 und des Kondensators 15 ein gepulstes Infrarotsignal von der Sendediode 14 abgestrahlt wird. In the meantime the capacitor 15 has discharged until its at the input 2 of the NAND gate 11 lying output potential is the lower breakover threshold of the NAND gate has reached This consequently switches back to state H and via the Inverter 12 blocks switching transistor 13 again. Then the cycle of front, so that, depending on the time constant r = R. C of the resistor 60 and the Capacitor 15, a pulsed infrared signal is emitted from the transmitter diode 14.

Jeweils in der Sperrzeit des Schalttransistors 13 lädt sich ein Kondensator 16 über einen Widerstand 64 wieder auf, der der Sendediode 14 die nötige Spannung gibt. Im Durchschaltezeitpunkt fließen durch die Sendediode 14 Spitzenströme in der Größenordnung von 1 Ampere. In each case in the blocking time of the switching transistor 13, a capacitor charges 16 through a resistor 64 again, the transmitter diode 14 has the necessary voltage gives. At the time of switching on, peak currents flow in through the transmitting diode 14 of the order of 1 amp.

Der Infrarotempfänger 20 weist in seinem Eingangskreis die Empfängerdiode 21 auf, die über einen Kondensator 30 auf den Eingang 3 eines zweistufigen Verstärkers (Operationsverstärker 22) gegeben wird Dabei arbeitet der erste Operationsverstärker nicht invertierend, der zweite Operationsverstärker invertietrend. Beim gewählten Ausführungsbeispiel wird ein Verstärkungsfaktor in der Größenordnung von etwa 100 000 erreicht. Dadurch ist eine große Empfindlichkeit gegeben, und auch noch kleine, von der Empfängerdiode 21 aufgenommene Signale können ausgewertet werden. The infrared receiver 20 has the receiver diode in its input circuit 21, which via a capacitor 30 to the input 3 of a two-stage amplifier (Operational amplifier 22) is given. The first operational amplifier works not inverting, the second operational amplifier inverting trend. At the chosen In the exemplary embodiment, a gain factor of the order of magnitude of about 100 is used 000 reached. This gives a great sensitivity, and also small, Signals picked up by the receiver diode 21 can be evaluated.

Die weitere Beschaltung des Verstärkers und des Eingangskreises mit Widerständen und Kondensatoren entspricht dem üblichen Aufbau derartiger Schaltkreise und braucht hier nicht näher erläutert zu werden. The further wiring of the amplifier and the input circuit with Resistors and capacitors correspond to the usual structure of such circuits and does not need to be explained in more detail here.

Nach dem Verstärker Gelangt das Eingangssignal über einen Kondensator 33, der Gleichstromanteile fernhält, auf eine Gleichrichterschaltung mit 2 Dioden 23 und 24, die einen weiteren Kondensator 34 auflädt Daran schließt sich ein weiteres NAND-Gatter 25 und ein drittes NAND-Gatter 26 an. Letzteres ist schließlich über einen Optokoppler 77 mit einem Triac 27 verbunden, der das über eine Brückengleichrichterschaltung 29 versorgte Magnetventil 28 schaltet. After the amplifier, the input signal is passed through a capacitor 33, which keeps out direct current components, to a rectifier circuit with 2 diodes 23 and 24, which charges a further capacitor 34. This is followed by another NAND gate 25 and a third NAND gate 26. The latter is finally over an optocoupler 77 is connected to a triac 27, which has a bridge rectifier circuit 29 supplied solenoid valve 28 switches.

Die Funktion des Infrarotempfängers ist wie folgt: Die Empfängerdiode 21 erhält das mit 20 kHz gepulste Infrarotsignal, das von der Arbeitshand reflektiert wird, dieses Eingangssignal wird durch den Kondensator 30 von Gleich-Signalanteilen des Umgebungslichtes entkoppelt und durch den aus den beiden Operationsverstärkern 22 bestehenden Verstärker V auf das ca. 100 000fache verstärkt. The function of the infrared receiver is as follows: The receiver diode 21 receives the infrared signal pulsed at 20 kHz, which is reflected from the working hand is, this input signal is through the capacitor 30 of DC signal components of the ambient light and decoupled from the two operational amplifiers 22 existing amplifier V amplified to about 100,000 times.

In der Gleichrichter-Schaltung wird der Wechselstromanteil des Eingangssignals, also das Infrarot-Signal, gleichgerichtet und lädt den Kondensator 34 auf. In the rectifier circuit, the AC component of the input signal, that is, the infrared signal, rectified and charges the capacitor 34.

Die Spannung des Kondensators 34 schaltet das NAND-Gatter 25 durch, wenn ein entsprechender Schwellenwert erreicht ist. Im dargestellten Ausführungsbeispiel liegt die Spannung am Eingang des NAND-Gatters 25 zwischen 1,8 bis 3,8 V, die Schaltschwellen dieses NAND-Gatters 25 liegen bei 2 V und 3 V, so daß ein sicheres Schalten gewährleistet ist Bei jedem eintreffenden Wechselsignal schaltet daher das NAND-Gatter 25 durch, solange das Signal groß genug ist Um Störungen, wie Lichtblitze, also falsche Lichtwechselanteile auszuschalten, ist das weitere NAND-Gatter 26 über eine als Integrierglied wirkende Kombination von Kondensator 36 und Widerstand 76 angesteuert, deren Zeitkonstante ca 20 ms beträgt Nach dieser zusätzlichen Schaltstufe sind alle nicht auswertbaren Signalanteile, beispielsweise die von Leuchtstofflampen mit Netzbetrieb, eliminiert Sinkt das reflektierte Infrarotsignal unter einen bestimmten Wert, so schaltet der Infrarotempfänger 20 wie folgt: Der Schwellenwert des NAND-Gatters 25 wird nicht mehr erreicht, da der Kondensator 34 sich nicht mehr auflädt Der Triac 27 wird nicht mehr versorgt und schaltet das Magnetventil 18 ab.The voltage of the capacitor 34 switches the NAND gate 25 through, when a corresponding threshold is reached. In the illustrated embodiment the voltage at the input of the NAND gate 25 is between 1.8 and 3.8 V, the switching thresholds this NAND gate 25 is at 2 V and 3 V, so that reliable switching is guaranteed is With every incoming alternating signal, the NAND gate 25 switches through, as long as the signal is large enough To avoid interference such as light flashes, i.e. incorrect light change components to be switched off, the further NAND gate 26 is to act as an integrating element Combination of capacitor 36 and resistor 76 controlled, their time constant approx. 20 ms. After this additional switching stage, none of them can be evaluated Signal components, for example those from fluorescent lamps with mains operation, eliminated If the reflected infrared signal falls below a certain value, the switches Infrared receiver 20 as follows: The threshold value of the NAND gate 25 is not reached more because the capacitor 34 is no longer charged. The triac 27 will not supplied more and switches the solenoid valve 18 off.

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Claims

Claims: 1. Device for switching on and off as required the main burner of a gas burner, in particular a Bunsen burner, with a constantly switched on pilot burner and with a solenoid valve in the gas supply to the main burner, indirectly through the distance between the working hand and the main burner is controlled in its two operating states (open - closed), characterized in that that an infrared receiver (20) is provided to control the solenoid valve (28) and an infrared transmitter (10), the direction of reception or direction of transmission of which has been selected are that at least part of the transmission power of the infrared transmitter (10) from the Working hand holding the object to be heated over the flame of the main burner (50) is reflected in the infrared receiver (20).

2. Device according to claim 1, characterized in that the infrared signal is amplitude modulated.

3. Device according to claim 2, characterized in that the infrared signal is amplitude modulated (pulsed) with a square wave signal.

4. Device according to claim 3, characterized in that the frequency of the square wave signal is 20 kHz.

5. Device according to claim 1-4, characterized in that the Infrared transmitter (10) includes a transmitter diode (14), which via a switching transistor (13) -with-the frequency of the square-wave signal is pulsed, and that the square-wave signal from a first NAND gate (11) controlling the switching transistor (13) from the supply voltage is produced.

6. Device according to claims 1-4, characterized in that the Infrared receiver (20) includes a receiver diode (21) whose output signal Via an amplifier (t 22) and a rectifier (23, 24) to a second NAND gate (25) reaches the solenoid valve via an optocoupler (77) and a triac (27) (28) controls.

7. Device according to claim 6, characterized in that the second NAND gate (25) followed by a third NAND gate (26) via an integrator (36, 76) is.

8. Device according to claims 1-6, characterized in that the sensitive surfaces of the transmitting diode (14) and the receiving diode (21) together the end face of the housing of the gas burner are pivotally arranged.

The invention relates to a device for on-demand and Switching off the main burner of a gas burner, especially a Bunsen burner, with a constantly switched on pilot burner and with a solenoid valve in the Gas supply to the main burner, which is generated indirectly by the distance between the working hand and the Main burner is controlled in its two operating states (open - closed).

Such a device is known from DE-PS 24 60 745 there a photoelectric cell is provided by covering it with the working hand the photoelectric resistance of the cell changes and thereby the switching process of the solenoid valve is triggered.

This arrangement has the disadvantage that by changes the room brightness can result in incorrect switching.

A second remedy has been proposed (DE-PS 26 43 509) to switch the photoelectric cell differently to this photoelectric cell, which compensates for such fluctuations in room light and thus operational safety of the burner improved.

In both known facilities there is an "outside light control" before, whereby the direction of incidence of light (except the position of the working hand) undesirably influence the response of the burner in certain situations can.

So even with the arrangement according to DE-PS 26 43509 with extreme spatial arrangements (e.g. unfavorable positioning of the work table, very shallow incidence of light in the evening or in the morning) or with body movements over the burner cannot rule out the possibility of incorrect switching, i.e. that the main burner is ignited, even if other parts of the body are the photoelectric Influence the control or in the case of unfavorable positioning despite the proximity of the working hand is not ignited relative to the incidence of light.

It is therefore the object of the invention to provide such a device to improve that a control of the solenoid valve exclusively by the movement the working hand takes place and external influences are completely eliminated.

This solves the invention in that to control the solenoid valve an infrared receiver is provided as well as an infrared transmitter, whose direction of reception or transmission direction are chosen so that at least part of the transmission power of the Infrared transmitter of the object to be heated over the flame of the main burner holding working hand is reflected in the infrared receiver.

The invention thus uses in contrast to the two known devices its own light source; the solenoid valve is therefore not controlled at Darkening of the receiver diode, but rather with reflections or scattering of the infrared light of the infrared transmitter into the infrared receiver.

This makes the facility completely free of external influences, especially since the "response range" of the receiver-transmitter arrangement is determined by the choice the appropriate sensitivity or amplification of the components involved on the crucial area, namely the position of the working hand in front of the main burner lets focus.

An advantageous embodiment of the inventive concept consists in that the infrared signal with a square wave signal with a frequency of about 20kHz is pulsed. This has the advantage that environmental influences in the form of radiation with Infrared portion can be eliminated.

Further refinements of the inventive concept are further subclaims refer to.