DE2424711A1 - OIL BURNER CONTROL ARRANGEMENT - Google Patents

Description

Patent Attorneys Dlpt.-Ing. R. BEETZ sen. '
Dlpl-Ing. K. LAMPRECHT

Dr.-Ing. R. B Ξ ETZ Jr.
• MOnohen 22, Stelnedorfstr. IS

572-22.65OP 21-5 1974

SUNDSTRAND CORPORATION, Rockford, Ill. V. St. A.

Oil burner control arrangement

The invention relates to the control or regulation of a heating arrangement, e.g. B. an oil burner, for example in residential buildings is used, with the burner responding to a heating signal or a heating command from a thermostat, which has a fuel supply and actuates an igniter to ignite the fuel.

In such an arrangement there is usually a proportionate delicate balance between fuel supply and air supply where clean, efficient combustion can be expected is. If the fuel is supplied without immediate ignition, or

572- (B 00739) -DW-r 4 ^ Q 8 5 1/0 7 5 0

when the combustion is initiated and thereafter accidentally or unexpectedly is interrupted, it is important that the fuel supply is interrupted immediately so that nothing is harmful to the device or dangerous situation for the personnel can arise. Accordingly, safety measures are important for a burner arrangement to be provided in the event that the flame does not ignite as required or goes out after ignition.

Control arrangements of the type mentioned that have already been developed use electromechanical regulators with moving parts that wear out. With more complicated controllers, numerous moving parts lead to a relatively short service life and costly maintenance problems. In addition, the regulators are often in mains voltage circuits which can be dangerous in the event of malfunctions and damage the components of the circuit.

In order to improve safety and reliability, regulators were also developed, the electronic components in low-voltage circuits use. U.S. Patent No. 3,624,407, for example, relates to a furnace control with electronic components in a low voltage circuit, a protective tube switch (reed relay) to control the burner depending on various excitation and holding windings provides. The US-PS 3,672,811 relates to a burner control, in which all control components are in a mains voltage circuit; the fuel supply is through a photosensitive Relay controlled, which is responsive to both an activation lamp and a stop lamp. Finally, U.S. Patent 3,463,600 relates to a burner control with two Flam men sensors and a fault indicator that indicates when one of the sensors is not works properly.

409851/0750

A burner control arrangement developed internally by the inventor has control components in a reliable low-voltage circuit that has an electronic switch to control a Contains burner control relay and remains energized for the duration of the thermostat heating command without separate excitation and holding devices required for the relay.

The object of the invention is to provide an improved burner control arrangement indicate with control components in a low-voltage circuit, with a device that works when the mains voltage is insufficient prevents operation, and with a device that indicates a shutdown of a flame sensor circuit.

The invention provides an improved burner control arrangement is provided in which a thermostat, a flame sensor and a safety switch are interconnected in a low-voltage semiconductor circuit, completely separate from the 110 V AC network. A mains voltage circuit contains only one burner motor for supplying air and fuel and one Igniter, along with a control switch for the engine and the igniter. When the thermostat switch closes in response to a heating command, run the control processes in the low-voltage control circuit from one another to the operating state of a flame sensor cell and the Safety switch before operating the fuel supply and igniter. If no flame is generated in a short time, the safety switch opens the control circuit to prevent the fuel supply and the actuation of the igniter; the arrangement can then only resume operation when the safety switch is reset manually.

409851/0750

In an advantageous embodiment, the flame sensor contains circuit an indicator lamp that is normally energized as long as the safety switch heater is energized to indicate that no flame was formed, or that insufficient light intensity was measured by the flame sensor, or that the Flame sensor circuit is interrupted. If a flame occurs, the indicator lamp is extinguished when the safety switch heater is not fed.

It is advantageous to use a forward breakdown diode or switching diode as an electronic switch, together with a Control relay, wherein a predetermined minimum voltage is required for operation, so that the control arrangement can not work when the mains voltage is not sufficient to ensure that the burner igniter and the burner motor function properly.

The invention thus provides a control arrangement for an oil burner with a motor for pumping fuel into the burner, with an igniter to ignite the fuel and with an electronic switch to control the energy supply to the engine and to the detonator, these devices being in a mains voltage circuit, further with a low voltage circuit for controlling the operation of the engine and the ignition switch, consisting of a relay for controlling the switch electrode, consisting of one second electronic switch and a thermostat connected to this for energizing the relay, from a third electronic Switch for operating the second switch, from a gate circuit for controlling the third switch, with a light-sensitive one Flame sensor cell and a lamp to display the operability the flame sensor circuit.

409851/0750

The invention will be illustrated by means of which consists of a single figure Drawing explained in more detail.

The figure shows a burner control arrangement constructed in accordance with the invention consisting of an opto-coupler between a low voltage control circuit and a mains voltage burner circuit, together with an indicator lamp for indicating a fault in the flame sensor circuit.

According to the figure, the mains voltage circuit consists of Lines 20 and 21 which are connected to the primary winding of a transformer 22. A burner motor 24 for supplying oil and Air in a combustion chamber is connected to line 20 via a connection 25 and to the line 21 via a connection 27 and a triac switch T connected. An igniter 28 is parallel to the engine 24 so that the engine and the igniter are actuated simultaneously.

The triac switch T contains a main connection MT connected to the connection 27, a main connection MT connected to the line 21, and a gate G which is connected to a control arrangement which actuates the switch when a heating command is issued by a thermostat. A resistor R lies between the triac connections G and MT and serves to prevent incorrect actuation of the triac, which can be caused by strong residual currents or leakage currents at high temperatures or by electrical stray interference signals. A resistor R ₁ and a capacitor C are located between the triac terminals MT and MT in order to limit the rate of change of the voltage rise on the triac T to a safe value when the triac switches from the on to the off state.

409851/0750

G -

The triac T is normally in its off or locked state when the thermostat does not issue a heating command. The gate G of the triac T is biased so that the triac remains conductive due to a collector current from a driver transistor T. The collector of the transistor T is connected to the triac gate G via a line 30 and a resistor R. The resistor combination R and R ₀ ensures that the door is correctly preloaded and

<3 German

with for the current of the Triac T. The base of the transistor T is connected to the emitter of a phototransistor T via a line 31

German

closed, and the emitter of the tra
32 connected to a line 33.

closed, and the emitter of transistor T is on a line

The base of the transistor T _n is through a capacitor C_ and

ζ 5

a capacitor C is connected to the line 33. The capacitors serve to stabilize the high-gain transistor pair T and T. The line 33 is via a line 36 and a Diode D connected to a tap on the primary winding of transformer 22. The collector of the transistor T is connected to a Wi-

German

derstand R connected. The phototransistor T speaks on light

4 German

a light emitting diode or light emitting diode or light emitting diode D the low voltage control circuit that responds to the thermostat. The light falling from the diode D onto the transistor T. causes a base current in transistor T, causing the phototransistor conducts and amplifies the small base current generated by the light to a much larger emitter current. Of the Emitter current from transistor T flows into the base of the driver

German

transistor T, so that this comes into saturation and a collector current to control the triac T pulls.

A09851 / 0750

The diode D and a capacitor C in the line 33 act as a one-way voltage source for the transistors T and T formed gate control circuit. The resistor R serves as a Current limiter for the transistors T and T.

_{A resistor R and a resistor R 14} are located between the conductors 31 and 33 - the resistors represent a shunt with a finite resistance value to the base-emitter path of the transistor T in order to divert the reverse current at high temperatures.

On the secondary side of the transformer 22 is the low-voltage control circuit connected. This circuit includes a thermostat with a normally open thermostat switch 40, the closes when the ambient temperature drops and triggers a heating command. The low voltage circuit also includes a flame sensor cell 42 from a photosensitive cadmium photoresistor next to a burner 43, so that the cell for the presence or The absence of a burner flame responds. Cell 42 is in the dark; H. without flame in burner 43, relatively high resistance, on the order of 50 k-Q. , and relatively low resistance (300 to 2000 jQ, depending on the distance of the cell from the flame), when the burner ignites.

The burner control arrangement is advantageously accommodated in a suitable housing 45, and only the burner motor 24, the igniter 28, the thermostat 40 and the cadmium cell 42 are outside of the housing 45. In order that the control arrangement can be correctly connected to the external components of the device, the Housing 45 has a connection L for connecting the mains voltage line

409851/0750

-S-

device 20, a connection L for connecting the mains voltage line 21, and a connection M for connecting the motor 24 and the igniter 28. In addition, the housing 45 contains connections T for connecting the thermostat and connections F for connecting the flame sensor cell 42.

The light emitting diode D and the phototransistor T can be used as one light relay 46 are understood, in which the diode D a control

of the relay element or switching element and the transistor T a controlled Form relay element or switching element.

In the low-voltage control circuit, the light-emitting diode D actuated depending on the closing of the thermostat switch 40, provided that certain other conditions are met, as can be seen from the description of the arrangement.

The low voltage circuit includes a safety switch with a normally closed switch contact 47 and one Heating coil 48, which causes the contact 47 to open after a predetermined period of about 15 to 45 seconds. After opening of the switch contact 47 this is held in the open position and must with the help of a button 49, which is from outside the housing 45 is accessible, can be reset manually. The size of the safety switch can be compared to that in U.S. Patent 3,624,407, but the present invention does not require a temperature compensated switch which is normally the case is required.

In order to provide the LED D with energy in the event of a heating command

A09851 / 0750

ensure, the diode is connected to the secondary winding of the transformer 22 via a circuit that includes: a line 50 between the grounded end of the secondary winding of the transformer and the safety switch 47, a line 51 between the safety switch 47 and the diode D, a line 52 leading away from the diode, a line 54 between the line 52 and an electronic switch T, a resistor R _1n , a diode D, a line 55 with a resistor R _Q between the diode D and the thermostat -40, and also one Line 56, which leads back from the electronic switch T to the secondary winding of the transformer. The electronic switch T is a breakdown switch, e.g. B. a controlled silicon switch. The switch T is preferably an asymmetrical silicon alternating current switch which is available for purchase as ST4. However, other switches can also be used, e.g. B. a unilateral silicon switch such as 2N4988.9 and a bilateral silicon switch such as 2N4991.

The thermostat 40, as usual, includes an anticipatory heating element in the form of a very small resistor 58. When the thermostat 40 closes due to a heating command, becomes the transformer secondary winding (+ 12V) Energy fed through the thermostat contact into the line 55, which contains the resistors R and R_. The wi-

o 7

resistors are thereby connected to the transformer secondary winding via the safety switch contact 47, which is a break contact (normally closed). In this condition, the resistors draw approximately 200 mA AC to operate the heating element 58 of the thermostat, which is usually present, - to prevent the thermostat from overshooting.

409851/0750

- OK -

The resistors R and R together with the diode 7 produce ο

D a predetermined bias and form a charging path for one Capacitor C in a line 59 for the negative power supply. Successive negative half-wave signals on the transformer secondary winding cause the capacitor C to charge in stages and controlled by the ratio of the resistors R and R

7th

to a negative steady-state voltage that is slightly below the breakdown voltage of the asymmetrical switch T. Assuming that the switch T blocks at a terminal voltage of less than 7 V, the capacitor C can generate a negative voltage of 6.5 V across the switch T. . >

The switching through or triggering of the asymmetrical switch T is controlled by a silicon rectifier (thyristor) T controlled to that of the transformer secondary winding incoming line 56 is connected. The thyristor T blocks normally and is connected to the heater 48 for the safety switch contact 47 connected. When the thyristor T turns on, the cathode voltage is applied to a resistor R _ and a potentiometer R. The tap of the potentiometer R transmits part of the rising Cathode voltage to one connection of the unbalanced

Switch T .. The other connection of switch T _A is set to a 4 4

negative supply voltage placed through the capacitor C

is formed during the negative half-waves of the transformer. When the superposition of these two voltages is the breakdown voltage of the switch exceeds T, it switches from its normal Au's state to its on or on state. Consequently at least one oscillation of both the positive and the negative transformer voltage is necessary in order to conduct T

409851/0750

act, with transient effects when closing the thermostat contact are prevented. A capacitor C is parallel to the unbalanced switch T and the resistor R, and a capacitor C is connected to the thyristor T and the heater 48 in order to prevent glitches and false triggering of the unbalanced switch T.
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When the thermostat 40 closes and there is still no flame on the burner 43, the cadmium cell 42 remains in its "dark" or high-resistance state. During the positive half-waves on the secondary winding of the transformer, the high resistance of the cell 42 causes the gate-cathode path of the thyristor T to be forward-biased by a bias network consisting of a resistor R _ft , a resistor R and a diode D. A sufficiently high gate current and a gate voltage occur at the thyristor T to switch T through so that it conducts a sufficient holding current through the heater 48 of the safety switch so that the thyristor remains conductive for the duration of the positive half-waves of the transformer voltage.

When the thyristor T turns on, it does three things: (l) It feeds a heating current into the safety switch heater 48, which ultimately causes the safety switch contact 47 to open, if within a time of about 15 to 45 s, depending on the distance between the cell ^: 42 from burner 43, no flame is formed on burner 43; (2) via the resistors R and R in the asymmetrical

X 3 Xo

see switch T fed in causes increasing cathode voltage, that T turns on and a current through the light emitting diode D and the resistor R conducts so that the burner motor 24 and the ignition

A09851 / 0750

the 28 are supplied with energy5 (3) the increasing cathode voltage causes the gate-cathode path from T to "break through backwards", with a limited current being passed through the resistor R and the light-emitting diode D., whereby the diode D sees ₁ -

4 4

emits clear light and indicates that there is no flame is, and that the control arrangement is in the test phase in which the safety switch heating element 48 is supplied with energy will.

The ohm see heater 48 in the safety switch heats after the Consumption of current from the thyristor T a bimetal in the safety switch that opens the safety switch contact after a predetermined time. The switch is usually set to that he has the safety contact 47 after 15 to 45 s of continuous heating of the Heater 48 opens. If no flame occurs during this time as long as the thermostat 40 is closed and issues a heating command, opens contact 47 to control the energy from the low voltage remove circuit, whereby the entire burner control arrangement is blocked. When the safety switch contact is opened once it remains open and must be reset by hand.

When the unbalanced switch T is in the conductive state has switched through, it remains in this conductive state, so that a current flows through the light emitting diode D and the current limiting resistor R.

O J. U

flows through until the mains voltage is switched off or until the safety switch contact 47 or the thermostat contact 40 is opened. As long as T is conducting, the light-emitting diode D also conducts and emits light to the base of the phototransistor T to operate the burner motor 24 and detonator 28. The tap of the potentiometer R is

409851/0750

preferably set such that the unbalanced switch T does not switch through and conducts for voltages lower than about 90 V. Thus, the low-voltage control circuit cannot be supplied with energy when the mains voltage is lower than the voltage suitable for operating the burner motor 24 and the igniter 28. Before setting the potentiometer R, the resistor R is used to protect the unbalanced switch T from an excessively strong current, if the tap of the potentiometer R is set accidentally is e.g. B. on an extreme position of the potentiometer.

If the flame at burner 43 occurs during the 15 to 45 s test phase before the safety switch contact 47 opens, which is normally the case when the control arrangement is working properly, the resistance in the flame sensor cell 42 is set to a low value between 300 and 2000 / 1 is reduced, depending on the distance between the cell and the flame. The low resistance of the flame sensor cell biases the gate-cathode path of the thyristor T in the reverse direction, so that T switches off. If the switch T does not conduct, the heater 48 in the safety switch 47 is not operated, so that it cools down and the contact 47 remains in the normally closed position. As a result, the burner continues to work until the thermostat issues a heating command and the Flammensensorzel le detects a corresponding flame condition.

The diagnostic display, the light-emitting diode D, lights up as long as the heater 48 is supplied with energy. The flame sensor circuit is thus monitored during this time. The excitation of the diode D indicates that the safety switch heater 48 is being supplied with energy and the test phase is over. During this trial

409851/0750

phase, when the diode D is not energized, indicates the absence of the borrowed

tes that no flame was formed, or that the light was not for the flame sensor cell 42 is sufficient, or that the flame sensor circuit is open. Thus, at the time of the test phase, an operator can Immediately determine what is going on in the flame sensor circuit. If during the test phase, a flame in suitable Way was produced in the burner 43, the light-emitting diode D is switched off when the safety switch heater 48 is switched off is.

The light emitting diode D and the phototransistor T are advantageous in

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combined into a single, commercially available integrated circuit, z. B. in the opto-coupler MCT 26 from Monsanto.

The switches T and T to T can, for example, be as follows Bear manufacturer designations:

T - 64149 special

T - 2N5305

T - ST-4

T - C103Y, TIC-44

The following types can be used as diodes D , D and D:

L. German 4th

- 1N4002

D-1N4148

German

D, - RL-50 4

409851/0750

'- 15 -

The values of the capacitors C -C generally have the following values:

C - 0.1 uF, 400 V

C - 200 uF, 25 V

C - 220 jiF, 16 V

C - 0.1 uF, 25 V.

C ₅ - 270 pF to 390 pF, 25 V

C - 270 pF to 390 pF, 25 V.

C ₁₇ - 0.1 ^ uF, 50 V

The resistances R - R have approximately the following values:

- X X3

R - 100 ohms, 1/2 W.

R - 820 ohms, 1/2 W.

R - 68 ohms, 1 W.

R - 1.8 kOhm, 1/2 W.

R - 33 kOhm, 1/2 W.

R, - 18 kOhm, 1/2 W ο

R - 22 ohms, 3 W, 5%

R ₀ - 40 Ohm, 3 W, 5% ο

R - 390 Ohm, 1/2 WR ₁₀ - 150 Ohm, 1/2 W R ₁₁ - 820 Ohm, 1/2 W.

40985 1/0750

R- 820 ohms, 1/2 V
R - 100 kOhm, POT
R - 33 kOhm, 1/2 W.
R - 4.7 kOhm, 1/2 W.

In summary it can be said: If there is no heating command, the thermostat switch contact 40 is normally open, and the elements of the arrangement are in the rest position. When the thermostat switch closes, an electrical circuit is made to the gate of the thyristor T connected. When the flame sensor cell 42 is correct works and there is no flame, the high resistance of the cell causes the thyristor T to conduct. When T leads a circuit is formed by the safety switch heater 48, which starts the test phase. At the same time the indicator diode D excited. Conducting the thyristor T causes the unbalanced Switch T turns on, so that a circuit for energizing the light emitting diode D is formed, whereby light to the phototransistor T is transmitted. The output from the phototransistor T. Current causes transistor T to conduct. The collector current

of the transistor T biases the gate G of the triac T in such a way that this remains conductive and supplies the burner motor 24 and the igniter 28 with energy. The motor drives a pump for supplying heating oil to burner 43, and the igniter causes the fuel to ignite. The presence of a flame reduces the resistance in the flame sensor cell 42, so that the thyristor T remains blocked.

The indicator diode D is not energized. The heating coil 48 is also not fed, and the safety switch contact 47 remains closed.

409851/0750

If for any reason the normal operating cycle described above is not completed, there will be no flame in the burner educated; the high resistance in the unlit flame sensor cell 42 causes the thyristor T to remain conductive until the heater 48 opens the safety switch contact 47, whereby the arrangement is switched off until it is operated by hand.

The arrangement provides for security measures. If a fault occurs, e.g. B. when the thermostat connections T short-circuited and the flame sensor connections F are open, the burner control can start, but it is not maintained longer than for the time the one for the heater to open the safety switch contact 47 is required since there is no reduction in resistance to leave the thyristor T in the blocked state. If the flame sensor connections F are short-circuited, the Never start the burner control as the thyristor T blocks. if the safety switch heater 48 is interrupted, the thyristor T does not receive sufficient holding current to conduct, whereby the unbalanced switch T remains off and the controller cannot use.

409851/0750

Claims (13)

Claims / 1. j burner control arrangement,
marked by: a) a device (22) for a low voltage source with a normally closed safety switch (47); b) a control switching component connected to the low voltage source (D); c) a thermostat switch connected to the control switching component (40), which makes the arrangement responsive to a heating command by closing; d) a heater (48) for the safety switch; _{e) a normally locked electronic switch (T 5} ) connected to the low voltage source and the safety switch heater; _{f) a trigger circuit (R 11} ) connected to the low voltage source and the thermostat switch for triggering the electronic switch; g) a light-sensitive flame sensor (42) in the trigger circuit for the electronic switch, which is normally relatively high-resistance in order to bias the electronic switch in such a way, that without the burner flame and with the thermostat 409851/0750 mostat switch conducts, and that in the presence of a burner flame is relatively low resistance to bias the electronic switch in the locked state when the burner is ignited Has; and h) one on the trigger circuit for the electronic switch Indicator (D,) that can be excited during excitation of the safety switch heater 2. burner control arrangement,
marked by: a) a device (22) for a low voltage source with a normally closed safety switch (47); b) a control switching component connected to the low voltage source (D) 5 c) a thermostat switch connected to the control switching component (40), which makes the arrangement responsive to a heating command by closing; d) a first, normally locked electronic switch (T) connected to the control switching component and the thermostat switch is connected to energize the control switching component; e) a trigger circuit connected to the low voltage source (R) for triggering the first electronic switch including a second normally disabled electronic switch (T); f) a heater connected to the second electronic switch (48); A098B1 / 0750 r 20- g) one connected to the low voltage source and the thermostat switch Trigger circuit (R) for controlling the second electronic switch; h) a light-sensitive flame measuring sensor (42) in the control circuit for the second electronic switch, which is normally relatively high-resistance, to the second electronic switch biased so that it is without the burner flame and with the Thermostat switch conducts, so that the safety switch heater is energized, and that in the presence of a burner flame is relatively low resistance in order to bias the second electronic switch in the blocking state when the burner is ignited has so that the heater is turned off; and i) one on the trigger circuit for the second electronic switch visual indicator (D) that can be excited while the safety switch heater is excited 3. burner control arrangement according to claim 2, characterized in that that the visual indicator is a light emitting diode. 4. burner control arrangement according to claim 2, characterized in that that the second electronic switch is an asymmetrical switch that depends only on a minimum breakdown voltage remains conductive. 5. burner control arrangement according to claim 2, characterized in that that the unbalanced switch is an unbalanced silicon trigger element. 409851/0750 6. burner control arrangement,
marked by: a) a device (22) for a low voltage source with a normally closed safety switch (47); b) a control switching component connected to the low voltage source ent (D); c) a thermostat switch connected to the control switching component (40), which makes the arrangement responsive to a heating command by closing; d) an asymmetrical switch (T) which is connected to the control switching component and the thermostat switch for energizing the control switching component depending on a predetermined breakdown voltage; e) an actuator (48) for the safety switch; f) an actuator circuit (T) for energizing the actuator after closing the thermostat switch; and g) a Flam men sensor (42) in the actuator circuit for Switching off the actuator after the formation of a burner flame. 7. burner control arrangement,
marked by: 409851/0750 a) a device (22) for erne low voltage source with a normally closed safety switch (47); b) a control switching component connected to the low voltage source (D); c) a thermostat switch connected to the control switching component (40), which makes the arrangement responsive to a heating command by closing; d) a passage breakdown switch (T) which is connected to the control switching component and the thermostat switch for energizing the control switching component depending only on a predetermined minimum breakdown voltage; e) a trigger circuit connected to the low voltage source (R) to trigger the breakdown switch, including a two- th, normally locked electronic switch (T); f) a heater connected to the second electronic switch (48) for the safety switch; _{g) a trigger circuit (R 11} ) connected to the low-voltage source and the thermostat switch for triggering the second electronic switch; and h) a light sensitive flame sensor (42) in the trigger circuit for the second electronic switch, which is normally relatively high-resistance, to the second electronic switch biased so that it conducts without a burner flame and with the thermostat switch closed, and that when it is present 409851/0750 '- 23 - a burner flame is relatively low resistance to the second to bias the electronic switch in the locked state when the burner has ignited. 8. burner control arrangement according to claim 7, characterized in that that the breakdown switch is an unbalanced silicon trigger element. 9. burner control arrangement according to claim 7, characterized by an indicator which is dependent on the trigger circuit for the second electronic switch during energization of the safety switch heater is excitable. 10. burner control arrangement,
marked by a) a mains voltage source (20, 21) with a selectively excitable Burner device (24, 28) 5 b) a first electronic device connected to the burner device Switch (T) with a gate (G) for triggering the switch; c) a light-sensitive component (T) connected to the gate, to let the gate guide; d) means (22) for a low voltage source; e) a luminous component (D) for transmitting light to the light-sensitive Component; 409851/0750 f) a thermostat (40) connected to the low voltage source and the light-emitting component to make the arrangement responsive to a heating command; g) a forward breakdown circuit (T) connected to the light-emitting device and the thermostat to excite the light-emitting device in response to a predetermined breakdown voltage; h) a third, normally connected to the low voltage source locked electronic switch (T) to the forward breakdown circuit to leave leading; i) one connected to the low voltage source and the thermostat Trigger circuit (R) for triggering the third electronic switch; and j) one to the trigger circuit for the third electronic switch connected light-sensitive flame sensor cell (42), which is normally is relatively high resistance to trigger the third switch without a burner flame and with the thermostat closed, and which is relatively low resistance in the presence of a burner flame in order to leave the third switch blocked when the burner has ignited. 11. burner control arrangement according to claim 10, characterized in that that the forward breakdown circuit is an unbalanced silicon trigger element. 409851/0750 12. burner control arrangement,
marked by a) a mains voltage source (20, 21) with a selectively excitable Burner means (24, 28); b) a first electronic device connected to the burner device Switch (T) with a gate (G) for triggering the switch; c) a light-sensitive component (T) connected to the gate, to let the gate guide; d) a device (22) for a low voltage source with a normally locked safety switch (47); e) a luminous component (D) for transmitting light to the light-sensitive Component; f) a thermostat (40) which is connected to the low voltage source and the light-emitting component to make the arrangement addressable to make a heat command; g) a second electronic switch (T.) which is connected to the lighting component and the thermostat in order to excite the lighting component, including a gate (R _1n ) for triggering the second electronic switch; h) a third, normally blocked electroni connected to the low voltage source
to let said gate lead: sometimes locked electronic switch (T) to the last 40 9851/0750 i) a heater connected to the third electronic switch (48) for the safety switch; _{j) a gate (R 11} ) connected to the low voltage source and the thermostat for triggering the third electronic switch; k) one connected to the gate for the third electronic switch, light-sensitive flame sensor cell (42), which is normally is relatively high resistance to trigger the third switch without a burner flame and with the thermostat closed, and the is relatively low resistance in the presence of a burner flame, in order to leave the third switch blocked when the burner is ignited; and l) a visual indicator (D) that depends on the gate circuit for the second electronic switch can be excited while the third switch is conducting. 13. burner control arrangement,
marked by a) a mains voltage source (20, 21); b) a selectively excitable burner device (24, 28) in the mains voltage source ; c) a first electronic device connected to the burner device Switch (T) | d) a trigger circuit (G) for triggering the switch, including a controlled switching component (T_); 409851/0750 - 27 - e) a device (22) for a low voltage source with a normally closed safety switch (47); f) a control switching component (D) which is connected to the low voltage source is connected for controlling the controlled switching component; g) a thermostat connected to the control switching component (40) to make the assembly responsive to a heating command; h) a forward breakdown circuit (T) connected to the control switch component and the thermostat to the control switch component to excite; i) a trigger circuit connected to the low voltage source (R ₀ ) to trigger the breakdown circuit, including a third o th electronic switch (T); j) a heater connected to the third electronic switch (48) for the safety switch; _{k) a gate circuit (R 11} ) connected to the low voltage source and the thermostat for triggering the third electronic switch; l) a light-sensitive flame sensor in the gate circuit for the third electronic switch, which is normally relatively high-resistance, the third switch and the heater without a burner flame and to trigger with the thermostat closed, and relatively low resistance when a burner flame is present 409851/0750 is to keep the third switch and the heater locked when the burner has ignited; and m) a light-emitting diode (D.) which can be excited during the excitation of the third switch.
4th 409851/0 750