SU1098146A2 - Device for arc welding with short circuits of arc gap - Google Patents

Abstract

DEVICE FOR ARC WELDING WITH SHORT CIRCUITS ARC SPRAY IO auth.St. No. 1058169, characterized in that, in order to improve the quality of the welded joint by excluding the electrode being immersed in the weld pool, a series-connected diode, a sectioned resistance and a voltage relay connected in parallel to the arc gap are introduced into it, a parallel-connected relay and partitioned resistance, and the sensor for continuous monitoring of jumper dimensions is provided with an additional forced excitation output, which through a normally closed contact The voltage is connected to the input of the thyristor key. (O from 00 4 O)

Description

The invention relates to the field of technological processes, in particular, to direct current welding with short-circuits of the arc gap.

It is known device auth.St. No. 1058169, containing a welding head connected to a power source through inductive resistance, a thyristor / -k switch with forced commutation and shunting its variable resistance, included in the welding circuit, as well as a control circuit containing a jumper size sensor, lin1t delays, defining a pause in the flow of the welding current, and a delay line metering the energy used to determine the electrode metal.

The main disadvantage of this device is the poor quality of welding due to the violation of the process due to the possible freezing of the electrode of the weld pool, which occurs during the operation of switching off - turning on the thyristor key.

The purpose of the invention is to improve the quality of the welded joint due to the failure of the electrode to be immersed in the weld pool.

The goal is achieved by the fact that in the arc-welding device with short-circuits of the arc gap, according to ed. No. 1058169 introduced a series-connected diode, a sectioned resistance and a voltage relay connected in parallel to the arc gap, a capacitor connected in parallel to the voltage relay and a sectioned resistance, and the continuous size control sensor nepehjbi4KH provides an additional output forcing the south excitation through a normally closed contact A voltage relay is connected to the on input of a shooting star key.

The drawing shows a diagram of the device.

An arc welding device with short arc gap knobs contains a welding head 1, connected (1 to source 2 of the power supply through a capacitive resistance 3, a thyristor switch with forced switching 4 and shunting its variable resistance 5, connected in series to the welding circuit, and also

a control circuit comprising a sensor for continuous monitoring of the dimensions of jumper 6, a delay line defining a pause in the flow of the welding current 7, and a delay line,

the metering energy for melting the electrode metal 8, while parallel to the arc gap there is a prey-chain, consisting of series-connected blocking

a diode 9, a partitioned resistance 10, and a voltage relay 11, of which the last two elements are shunted by a capacitor 12, the sensor 6 comprising four

0 output channels, namely, the return channel of lines 7 and 8 delays to the initial state of the TNG in case of an accidental short circuit, the channel of the end of a short circuit, the channel

5 start of the short circuit and the channel of the forced excitation, which through the normally-closed contact 13 of the voltage relay 11 is connected to the switching input of the thyristor-key 4.

The device works as follows.

In the process of welding, at the beginning of a short circuit, the sensor 6 generates a pulse to turn on the thyristor switch 4. At the same time, a short circuit current Egi flows in the welding value,

At the moment of rupture nepeND) i4KH, sensor 6 generates pulses to turn off the thyristor switch 4 and to turn on the delay line 7, a pause current flows in the circuit, the magnitude of which is determined by the parameters of the variable active resistance 5. After the delay line 7 ends, it generates the control impulses to turn on the delay line 8 and the thyristor switch 4. From this moment, the energy going to the pressure of the electrode metal is dispensed. After the end of operation of the delay line 8, a control pulse is applied to the switching-off input of the thyristor switch 4. Wherein

5 thyristor 1Y key 4 turns off and

a pause current flows in the welding circuit. Further, at the beginning of the next short jam, the sensor 6 is abacted.

the control pulse to turn on the thyristor switch 4 and the whole cycle repeats again.

A feature of the operation of this device is that the thyristor switch 4 has an insensitivity zone, namely, there is a probability of its non-switching on during the interval of the switching processes in it. Therefore, if the delay line 8 generates a control pulse to turn off the thyristor key 4 and immediately the sensor 6 generates a control pulse at the beginning of a short circuit to turn on the thyristor key 4, then this command will not pass due to the unavailability of the thyristor key 4 to turn on. The current in the welding circuit in this case will be limited at the level of the pause tokh and freezing of the electrode to the weld pool will occur, which will lead to disruption of the process, its stopping and deterioration.

This disadvantage is eliminated due to the presence of a forced excitation unit. When the arc of the relay is energized, the voltage triggers and opens its normally closed contact 13, which opens the forced excitation channel. The capacitor 12 is thus charged with the polarity indicated in the drawing. When the electrode freezes or long-term short-circuits, the circuit of series-connected elements 9-1011 becomes short-circuited. The capacitor 12 begins to discharge by the total value of the variable resistance 10 and the ohmic resistance of the coil of the voltage relay 11. In this case, there is a constant discharge, depending on the magnitude

0981464

total resistance. As soon as capacitor 12 is discharged to the voltage at which relay 11 trips on release, its normally closed contact 13 closes and forced arcing of the arc occurs, which is energized, and the arc voltage applied to charge the capacitor 12, relay 11 trips. and opening his contact 13.

In other words, by changing the parameters of the partitioned resistance 10, it is possible to regulate the discharge time of the capacitor 11, and consequently, the delay time of its response to release.

Therefore, the condition for the normal operation of the forspring excitation unit will be the following condition:

BUT. ,

I OTP L k. J MCvKC

delay time

Where

- OTP. tripping of the release voltage relay,

. t maximum possible

K.j-McxKc short circuit time, which depends on the wire diameter, process speed, idling voltage, etc.

The proposed device has great advantages over the known. So, for example, the use of this device during the installation of main pipelines allows to exclude the stoppages of the technological cycle, as well as to exclude the lack of penetration due to process disturbances. All this provides the best quality indicators. welding process.

Claims (1)

ARC WELDING DEVICE WITH SHORT ARC INTERVAL CLOSES No. 1058169, characterized in that, in order to improve the quality of the welded joint by eliminating the freezing of the electrode to the weld pool, series-connected diode, sectioned resistance and voltage relay connected in parallel to the arc gap, a capacitor connected in parallel to the voltage relay and sectioned resistance are introduced into it and continuous monitoring of sensor sizes webs provided with a further output of the forced driving, which via a normally closed relay contact voltage _Q eniya vklyuchayu- connected to the S input of the thyristor present key. SU „, 1098146