RU1809248C - Flame control device - Google Patents

Abstract

Usage: automatic control of the presence of flame in the combustion chambers of heat engineering units. The inventive flame control device comprises a power supply unit 1, an ultraviolet sensor 2 connected by a cathode output to the first input of the standby multivibrator 3, the first output of which is connected to a signal conditioner 4, a signal conditioner 4 is connected to an electronic key 5, an electronic key 5 is connected to a switching unit 6 and flame indicator 7. The device is additionally equipped with a second signal conditioner 8 and a second electronic key 9, and the second signal conditioner 8 is connected by an input to the second output, I wait it multivibrator 3 and -c output control input of the second electronic switch 9 and the second electron ronny key 9 is connected to the anode of the ultraviolet sensor 2 and a second input of monostable multivibrator 3. 2 yl. THX

Description

The invention relates to metallurgy and heat engineering, in particular to devices for monitoring the presence of flame in combustion chambers

An object of the invention is to increase the reliability of a flame control device.

In the proposed device, the second output of the standby multivibrator directly generates such an output signal that occurs only in the presence of a shorted state of the sensor. This signal controls the operation of the additional driver and the electronic key. The joint functioning of these blocks leads to the fact that these blocks disconnect the supply voltage, which is applied to the sensor at the moment of its shorted state. This provides increased reliability of the proposed device.

Figure 1 shows a functional diagram of a flame control device; figure 2 is a timing diagram of its operation.

The flame control device contains a power supply unit 1, an ultraviolet sensor 2 connected to the cathode output with the first input of the standby multivibrator 3, the first output of which is connected to the signal conditioner 4, the signal conditioner 4 is connected to the electronic key 5, the electronic key 5 is connected to the switching unit b and an indicator flame 7, an additional signal conditioner 8 is connected to the input of the second output of the standby multivibrator 3, and the output to the control input of the electronic key 9 ,. the electronic key 9, the first output is connected to the anode output of the ultraviolet sensor 2, and the second output is connected to the second input of the standby multivibrator 3.

The time diagram (Fig. 2) of the device operation shows:

Ui is the voltage at the first input of the standby multivibrator 3;

U2 voltage at the second input of the standby multivibrator 3;

1) h - voltage at the second output of the waiting multivibrator 3 ;. .

U4 — voltage at the output of signal former 8;

Us- voltage at the first output of the standby multivibrator 3.

The flame control device operates as follows.

The following supply voltages are supplied to the ultraviolet sensor 2 from the power supply 1 through the standby multivibrator 3 circuit:

- constant voltage to the anode of sensor 2;

- pulsed voltage to the cathode of the sensor 2, - and for the normal operation of the sensor 2 it is necessary that the electronic switch 9 in the initial state was open.

In the presence of a flame, the ultraviolet sensor 2 gives a pulse signal to the standby multivibrator 3 and starts the latter. Formed output multivibrator 3 output signals

sequentially ensure the operation of the signal driver 4, the electronic key 5, the switching unit 6 and the flame indicator 7. In Fig.2, this corresponds to the first and second half-periods of the time diagram,;

. The shorted state of the ultraviolet sensor 2 corresponds in FIG. 2 to the third and fourth half-cycles.

In the presence of a shorted state

sensor 2 at the second output of the standby multivibrator 3, a signal Uz is generated, which is input to the signal conditioner

8. ; ..; :.

At the output of the shaper 8, a pulse signal of duration (T) is generated, the value of which is determined by the formula

thirty

Tt T | Ti,

ABOUT)

where Ti is the duration of the half period of pulses generated by the sensor 2 and controlling the operation of the standby multivibrator 3 through its second input.

The generated signal 1M controls the operation of the electronic key 9, closing it for the entire duration of this generated signal. Closing the electronic key 9 in the presence of a shorted state

sensor 2 significantly increases the reliability of the device, since at the time of this condition the supply of voltage is temporarily stopped, and sensor 2 temporarily stops

functioning, while restoring its performance,

Example (specific implementation). As shaper 8, we use a differentiating RC chain for which the parameter Ti 10 (ms) (milliseconds) is known. Taking into account that the duration of the forming pulse (T) of the differentiating RC chain is determined by the formula

. T RC, (2)

 where R is the active resistance of the RC chain ;;

C is the capacity of the RC chain,

we select the values of the parameters R and C so that the duration of the generated pulse is determined in the range from 10 to 14 ms (formula 1). For example, we select the parameters R 10 (com) C 120 (μF), for which the duration T is 12 ms, i.e. the generated pulse falls within the range of its variation defined by Formula 1, increasing the reliability of the above device.

The proposed device in comparison with the prototype provides more reliable flame control due to the quick and stable response of this device to the shorted state of the ultraviolet sensor 1 and protection of the latter from this shorted state by blocking the supply voltage supplying to its cathode, which increases the safety of operation fuel-burning devices.

Claims (1)

SUMMARY OF THE INVENTION A flame monitoring device comprising a power supply unit, an ultraviolet sensor whose cathode is connected to a first input of a standby multivibrator, the first output of which is connected to a signal driver, the output of which is connected to an input of an electronic key connected to a switching unit and a flame indicator, characterized in that, in order to increase reliability, it contains a second signal driver and a second electronic key, and the input of the second signal driver is connected to the second output of the waiting mul tivibrator, and the output is with the first input of the second electronic key, the first output of which is connected to the anode of the ultraviolet sensor, and the second with the second input of the standby multivibrator.