DE1263971B - Electronic safety device for burner systems that responds to flame radiation - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

EDITORIAL

Int. Cl .:

F23n

German class: 24m-3

Number: 1263 971

File number: D 490081 a / 24 m

Filing date: December 23, 1965

Open date: March 21, 1968

The invention relates to an electronic safety device which responds to the flame radiation for burner systems that have a vibrator with two triodes and when the flame radiation hits a signal on your flame radiation detector to control a control or safety device, ζ. Β. from an automatic program control for gas or oil burner systems, from gas or oil valves, from alarm devices and the like.

Devices of various types for controlling burner devices as a function of Flame radiation is known, some of which use photocells. Such known devices show a number of evils, especially complex structure, weakness of the sent Signal and unreliability, the latter because of failures in the detector or in the connection lines to the detector (such as breakage or short circuit) are not recognizable as such and so when this occurs Error no alarm, no shut-off or shutdown of the system takes place. Of late or Defective alarms or shutdowns of the system can occur in the case of safety devices for gas burner systems high risk of explosion.

In order to prevent the latter disadvantage, a known safety device uses a pulsating signal; if there is an error or an interruption in the pulse cycle, that is a sign of a malfunction of the safety device, such as failure in the detector or in the connecting lines to the detector. However, there remains the disadvantage that as a flame radiation detector a photocell is used, which serves as a signal generator and only relatively emits a weak signal, which requires relatively complicated signal amplification measures. The output signal The safety device is also placed between the emitter and collector of a transistor removed, which serves as the one triode of the vibrator. The emitters correspond the cathode and the collector of the anode of a tubular triode. The averaged over the pulse train With this known arrangement, the voltage of the output signal does not change polarity, when there is a transition from the irradiated to the non-irradiated state of the flame detector.

Compared to this known safety device, the invention is based on the object that To largely simplify the safety device while at least maintaining the reliability or even to increase.

Electronic, on the flame radiation
appealing safety device for
Burner systems

Applicant:

Duiker Apparatenfabriek N.V.,

Rijswijk (Netherlands)

Representative:

Dipl.-Phys. Dr. rer. nat. J. Schirdewahn,
Patent attorney,
8000 Munich 55, Aichacher Str. 36

Named as inventor:
Rudolf van der Harst, Rijswijk;
Anne Leendert van den Broeke,
The Hague (Netherlands)

Claimed priority:

Netherlands of December 24, 1964 (6415 075)

It is known from control devices for oil-fired heating systems to use an ultraviolet-sensitive gas-filled diode as a radiation detector for the flame radiation, which, in contrast to a photoelectric detector, does not act as a generator, but as a valve permeable in one direction and has the disadvantage that it must be extinguished again after ignition by the flame radiation.
The invention is based on the knowledge that when a gas-filled radiation-sensitive diode is used as a radiation detector in a safety device of the type mentioned, the periodic extinction of the diode can easily be taken over by the vibrator, which is responsible for the

4-5 Generation of the intended for security reasons pulsating output signal of the safety device is provided anyway. In detail is after of the invention provided that a gas-filled diode, which, as is known per se, as the radiation detector serves, is arranged in a circuit which the two anodes of the vibrator triodes are coupled with Cathodes connects, and that the signal on the one hand

809 S19 / 257

3 4

between the coupled cathodes and, on the other hand, if the tube 3 is now replaced by ionizing radiation

the grid of the triode is removed, which development of sufficient strength is hit begins

Then, when the vibrator is in its stable supply- this tube to conduct electricity. The potential of the

is located, conducts electricity. Input side of resistor R ₇ rises and over

The device according to the invention is and the coupling capacitor C ₂ , which is now charged, is complicated and has only a few elements, also the potential of the grid g ₂ , which is not expensive and not vulnerable due to it. Counter triode B _{2 can be} conductive. The potential drop across the known safety device, from which at the anode a ₂ , which is a consequence of the conductive Zudie invention, is different EIe levels of S ₂ , is saved on the grid ^ ₁ over the elements, among other things because io no coupling capacitor C ₁ transmitted. The potential signal amplification of a weak signal generator, drop at the grid of the triode .B ₁ initially results in one like the photoelectric cell, is required. Reduction and finally an interruption of the invention also changes where the signal current flow through this triode B ₁ . As a result, unlike the known device vibrator, the state of the vibrator has changed: B ₂ is conductively blocked between the coupled cathodes of the triodes 15 and JS _1. Here, the terminal 1 of the vibrator on the one hand and the grid of the triode, negative with respect to the terminal 2, which is the final result of the radiation that conducts current when the vibrator is stable, the polarity of the tube 3, if applicable.

medium, output voltage of the safety device. However, this state is not stable. The condensate

tion, whereby a particularly striking difference 20 C ₁ and C ₂ discharge over the with them

resistances connected between the irradiated and non-irradiated state, while the tube 3

of the detector is given. erase is because the potential difference between the

As with the anodes Ci ₁ and a ₂ as a result of the potential increase known control device for oil burners, one of VOnG ₁ and the potential drop of a ₂ below the value type is preferably used as the detector, which has only fallen to the ultraviolet range 25, which is necessary is in order to keep the tube 3 suffering from the flame spectrum (2.0 to 2.8 A), so tend to hold.

that incorrect measurements are caused by visible light from others. The stable initial state of the vibrator is like this

Radiation sources can be safely prevented. restored, however the cycle starts from

The invention will be described in the following on the basis of a new one when the tube 3 is exposed to radiation

Wiring or circuit diagrams at an exit 30 remains. In this way, a permanent beam

management example explained in more detail. a pulsating voltage at the connection

The device is supplied with direct current, terminals 1 and 2 and a pulsating current in the

that by rectifying and smoothing the alternating signal or control circuit, the one with these connections

electricity can be obtained. connected, to the result.

The vibrator has the double triode B ₁ -B ₂ , 35 If one now considers the case in which the for

of which in the stable state B ₁ carries current, whereby tube 3 leading lines 4 and 5 are short-circuited.

the grid S ₁ are sen by means of the resistor or resistor. At first glance, the effect is that

A ₁ with respect to the common cathode k is positively the same as when the tube 3 is conductive: the vibration

power is. In this state of the vibrator the gate B ₁ -B ₂ begins to change its state and

Triode B ₂ non-conductive due to negative grid 40 returns after the capacitors C ₁ and C _{2 are discharged}

potentials, which returns to its stable initial state via a potential divider device, in which

is obtained, which then remains through the adjustable resistance, since in the circuit section 4, 5

stood R ₅ and the resistor R ₉ formed and flows continuously with a current of constant intensity

the anode a _{x is} connected. and so the double triode is not triggered.

A circuit 4, 5, which connects the anodes O ₁ and a _o ver 45 The connection terminals 1, 2 are the same, contains a gas-filled tube or diode 3, situation when the tube 3 is not conductive or its gas is ionized when it is ultraviolet the line section 4, S is interrupted. The irradiation is exposed, and also indicates that the alarm or control device, the high resistance R ₇ . If one is sufficiently connected to the terminals 1, 2, in high potential difference between the electrodes the 50 will react in the same way in such cases, is applied in the tube, this conducts current as soon as it is exposed to the radiation in which there is insufficient radiation is. The tube 3 and the circuit 4, 5 is interrupted (ie the circuit part containing the resistor R ₇ is on by breaking the lines or loosening the grid g ₂ over the capacitor or capacitance tube 3) and in which a short circuit in this C ₂ coupled. As a result, the electric circuit occurs at the electrodes, including a short-circuit tube 3, the same potential difference as between those in the tube itself. In all these cases, the anodes a _x and a _% , this potential difference control device inhibiting the burner device, but not sufficient, in order to switch off a current flow through or in order to generate a maximum of safety to the tube, provided that they do not receive the jet. Defects in lines 4 and 5 can be exposed to development. In this case, the Vi 60 easily occurs when, as is often the case, brator in its stable state, and between the detector 3 with a relatively large distance connecting terminals 1 and 2, which the signal to the rest Part of the device is transmitted to the control or alarm device, is an ordered one.

Potential difference across the interposed As already mentioned, the tube 3 is

resistance R ₁₀ from the potential difference between 65, preferably of a type that is based on ultra-

between the grid g _t and the cathode Zc ₁ , violet radiation derived from it is sensitive, which is particularly

is, the terminal 1 being positive compared to its advantage when used in gas burner systems

terminal 2 is. is. Such a gas-filled tube can internally

be covered with a layer of graphite, which serves as a cathode, with the anode in the center of the Tube is arranged. When the tube is exposed to ultraviolet radiation, the gas is ionized. When a sufficiently high voltage, the ignition voltage, is applied to the tube this conductive. After the end of the radiation, the gas remains in it for a short time ionized state, albeit with a high rate of decrease. When the vibrator is cyclical If the voltage on the detector is interrupted (for example twenty times per second), the tube goes out very much fast.

With a device constructed according to the invention and operation with a supply voltage from 250 V you can get a current of 30 μΑ at the connection terminals 1 and 2 in the normal or safety state received, d. H. when the flame is present. In the unsafe state, this goes Current essentially back to zero.

The sensitivity of the device can be regulated with the adjustable resistor R _5.

If desired, the anodes a _x and a _% can be connected to one another by a high-ohmic resistor so that the detector does not react when the detector is exposed to ultraviolet radiation of very low intensity, such as, for example, the ultraviolet radiation contained in normal daylight.

Of course, you can use two separate triodes instead of a double triode. Furthermore The triodes can be replaced by transistors, with the functions of the anode, the cathode and of the grid can then be met by the collector, the emitter and the base. Triodes and Transistors and their corresponding parts are to be regarded as equivalent in the context of the invention.

Claims (3)

Patent claims: 1. Electronic, responsive to the flame radiation safety device for burner systems, which has a vibrator with two triodes, characterized in that a gas-filled diode (3), which, as known per se, serves as the radiation detector, in a circuit (4.5 ) is arranged, which connects the two anodes (a _v a _s ) of the vibrator triodes (B ₁ , B ₂ ) with coupled cathodes (k) , and that the signal on the one hand between the coupled cathodes (k) and on the other hand the grid (g) the triode (B ₁ ) is removed, which then conducts current when the vibrator is in its stable state. 2. Device according to claim 1, characterized in that the grid (g ₂ ) of the triode (B ₂ ), which is not conductive in the stable state of the vibrator, via a potential divider (R _n , R ₉ ) to the anode (α, ) the other triode (B ₁ ) is connected, and that the resistor (.R ₅ ), which is arranged between the last-mentioned anode (O ₁ ) and the grid (g ₂ ) , is connected in parallel with a circuit which has a high resistance Contains resistor (R ₇ ) in the detector circuit and the capacitor (C ₂ ), which couples the detector circuit to the grid (g ₂ ) of the non-conductive triode (B ₂ ). 3. Device according to claim 1 or 2, characterized in that the gas-filled diode (3) is sensitive in a manner known per se to such ultraviolet radiation as in gas flames is available. Considered publications:
U.S. Patent No. 2,833,938;
Journal: »Die Ölfeuerung«, 1961, pp. 883 to 885. 1 sheet of drawings 809 519/257 3.68 © Bundesdruckerei Berlin