SU1488149A1 - Installation for controlling the process of welding of non-rotatable pipe joints - Google Patents

Abstract

The invention relates to a welding technique, is intended for programmed control of the process of arc welding of pipe sleeves, and can be used in mechanical engineering in the manufacture of critical products and main pipelines. The purpose of the invention is to increase reliability, expand the functionality of the installation and improve the quality of welded joints of non-rotary joints of pipes. The installation contains stabilization units, overload protection, logical control of welding mode parameters, an electric motor control unit. The rotational speed of the welding head is stabilized at each weld spot. The presence of a software block allows software regulation and solves the problem of the complex automation of welding of non-rotary pipe joints on products under installation conditions. 5 il.

Description

The invention relates to the welding technique and is intended for the integrated automation and software control of the gas-electric welding process of non-rotary pipe joints (none) with a non-consumable tungsten electrode.

The aim of the invention is to increase the reliability of the installation and the quality of the NST welding joints.

Figure 1 presents the functional diagram of the installation; figure 2 is a functional diagram of the software block; in FIG. 3, a functional diagram of the block of admissible logical control of the supply of gas, water and electric motor overload; Fig. 4 shows a control unit indicating inputs and outputs; Fig. 5 shows timing charts of operation of the control unit.

The installation includes (Fig. 1) software block 1, block 2 of the functionally varying: voltage, block 3 of the admissible logic control of gas supply, water and motor overload, block 4 of controlling the motor speed to the parameters of the current and voltage of the power supply, universal welding arc power source 5, voltage stabilization unit 6 on the electric motor, outboard welding head 7, overload and voltage protection block 8, direct current electric motor 9.

The main block of the setup is software block 1, in which the setting of the duration of the NST welding cycle and its breakdown into four time sections, in each of which

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The speed of the welding head gradually increases.

This unit is connected to unit 2 by a functionally varying voltage, which, at the time of transition of the welding head from site to site, gradually changes its speed and eliminates burn-through on the pipe.

The output linearly varying voltage from this block through the key elements of the control unit 4 is supplied to the voltage stabilizing unit 6 on the electric motor. From this unit, the voltage enters the protection and overvoltage protection unit 8. The unit 8 is connected via a feedback circuit to the unit 6, the unit 3 of the logic control, and the power source 5 of the welding arc. The protection unit 8 causes the control signal in case of an emergency to shut off the arc power source 5 and turn off the stabilization unit 6. Through block 8

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Tel (MB), Smoothing Filter (FS), Semiconductor Voltage Regulator (PS), Voltage Amplifier (UN), Inverting Cascade (IR), Waiting Multivibrator (MF), Symmetric Trigger (CT), Logic device overload a coincidence circuit (CC) and a relay amplifier (RU) with indication of output parameters. When the protective gas is supplied, the float of the rotameter crosses the luminous flux from the bulb to the photodiode of the sensor. At the output of the voltage amplifier, a pulse with smooth front and rear rising edges appears, which is fed to the input of the inverter, and from there to the waiting multivibrator. The multivibrator converts the input signal into a square pulse and flips the trigger. The latter delivers a control signal to one of the inputs of the coincidence circuit, to the other two inputs of which a control is also supplied.

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voltage is applied to the electric motor 25 signals from the reed sensor

9, and from it to the welding head 7, where the arc voltage from the power source 5 is applied.

The tolerance logic control unit 3 is connected with the control unit 4 and the protection unit 8 and controls the flow of gas, water to the welding head and the overload of the electric motor by signals from the sensors.

Software block 1 (FIG. 2) includes a bridge rectifier (MB), a smoothing filter (FS), a parametric voltage regulator (PS), a composite compensatory voltage regulator (CS), a thyristor switch (TC) and a time relay ( RV). Block 1 is a program-time device and sets the required rigid program for the NST welding cycle.

Unit 2 is a functionally changing 45 Mpulsov stabilizer. The power source provides NST welding. Post-voltage includes resistive voltage dividers, a linearly-varying voltage generator and an emitter follower with feedback. Using voltage dividers, setting Q gives the required welding speed at each programmable section depending on the diameter of the pipes.

The unit 3 for the admission logic control of gas supply, water and motor overload (Fig. 3) consists of a tolerance control device for the supply of protective gas containing a photo sensor (PD) and a bridge rectified alternating current in a pulsed and continuous mode, the welding arc .

The input voltage stabilization unit 6 of the electric motor is a transistor compensating stabilizer with a series-connected component regulating element, a single-stage UPT, a comparison element and a reference voltage source made according to the parametric stabilizer circuit. the EU has significant

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and block 8 protection. The coincidence circuit includes a relay amplifier, which supplies the enable signal to control unit 4,

The motor speed control unit 4 and the parameters of the current and voltage of the power supply comprises a bridge rectifier, a filter, key elements for supplying control voltage from block 2 to the voltage stabilizing unit 6 on the electric motor, switching relays to control the arc power source 5 and switch ElectroUniversal power source of the welding arc contains a step-down transformer, a thyristor current switch, a choke coil, a generator

and alternating current in pulsed and continuous modes, the welding arc.

The input voltage stabilization unit 6 of the electric motor is a transistor compensating stabilizer with a series-connected component regulating element, a single-stage UPT, a comparison element and a reference voltage source made according to the parametric stabilizer circuit. the EU has significant

Efficiency, has a high coefficient of stabilization and compensates for the effects of various destabilizing factors. The hinge welding head 7 consists of a removable electric rotation drive, a water-cooled burner and a faceplate,

The collector current and gas supply and the minimum dimensions of the rotating parts of the welding head allow automatic welding of the NST under mounting conditions at any position of the product in space.

The overvoltage and overvoltage protection unit 8 consists of an electronic circuit with a speed of 10 MKS, made on the overload signal sensor and an amplifier, as well as a relay amplifier with a speed of 500 ms. BZ eliminates unacceptable overload of the circuit elements and locks the regulating transistor of the stabilization unit 6 when the current reaches the maximum load value. The installation works as follows.

When applied to a voltage installation of 220 V, power is supplied to all the functional blocks of the circuit, with the exception of the welding head 7 and the electric motor 9 (Fig. 1). .

If there is water in the cooling system of the welding torch, a reed sensor is activated, which, through normally open contacts, delivers a control enable signal to one of the inputs of the coincidence circuit of control unit 3. The presence of protective gas in the welding torch is monitored by the photoelectric sensor of unit 2, from the output of which the control signal is fed to the second input of the circuit coincides. The third input of the coincidence circuit is open, and a constant level is applied to it via the overload relay contacts of the protection unit 8. This condition of the coincidence circuit allows the motor to start and turn on by motor 4 when pressing the Start button located on the control panel turns on software block 1, which is a temporary device with key elements that starts block 2 of the functionally varying voltage. In this block, the variable control voltage is integrated, the level of which is

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Secondly set by variable resistors depending on the required welding speed, this voltage through the key elements of the control unit 4 is fed to the control input of the motor voltage stabilizing unit 6, from the output of which the voltage stabilized in the temporary section goes to the overload protection unit 8 electric motor. In the event of an electric drive jamming and overloading, the protection unit 8 causes the required level of control voltage and locks the feedback transistor of the stabilization unit 6 along the feedback circuit, and also outputs the signal from the relay amplifier to the emergency shutdown of the power source 5 of the welding arc. In addition, the protection unit 8 removes the control signal in the coincidence circuit of the control unit 3. This block outputs a inhibitory signal to control block 4, which stops the process, i.e. movement of the welding head around the joint of the pipe, and turns off the arc power source,

In the absence of an overload, the welding torch rotates from the electric motor around the pipe with the speed set at each section, determined by the program block 1 and block 2 of the functionally varying voltage.

The technological process of welding fixed pipe joints is carried out in the following sequence,

On the pipe being welded install-. welding head so that NST welding starts at zenith. From the network, the installation, the arc power source is turned on, the required welding current is set on the remote control panel,

In accordance with the NST welding mode map, the required welding time for each pipe section is set on the program block.

Water is supplied from the plumbing network through a hydraulic reed sensor to cool the welding torch. A rotameter uses a photo sensor to determine the required flow rate of protective gas for NST welding, which is indicated by the light indication. The Start button is pressed, located on the remote control unit of the installation, Curtain arc welding, and after 71

for 3-5 s, the welding head begins to rotate smoothly around the pipe at the required speed. After the seam overlaps, the welding current automatically decreases after a certain time, and the head stops: the welding process is completed

Consider the operation of the control unit (Fig. 4).

When the protective gas is supplied to the welding zone and water, a long-lasting permitting signal appears at the 3rd inlet of the control unit (Fig. 4) into the cooling system of the welding head.

tu (figure 5), coming from the unit of logical control of the installation. The automatic start of the pipe welding cycle is performed by pressing the Start button located on the remote control. In this case, the 1st input of block 4 receives a control signal from block 1 (block 1 of the rear programs determines the duration of the entire cyst 1sh welding pipe and conditionally breaks the perimeter of the joint into four temporary regulated sections I-IV), OT joint influence of two signals The heats, and at the 1st output of block 4, a signal t appears to control the source 5 and turn on the welding arc. The arc ignites, the current of which is set by the welder on the remote control of unit 4.

The 2nd input of block 4 is supplied from block 2 by a control voltage, the level of which is set by variable resistors depending on the required speed of pipe welding. This is a functionally varying voltage. Duration ta through transis0

a switch that is controlled from block 3, and a delay line appears at the 2nd output of the control unit with a time delay t, after ignition of the welding arc. Voltage Uau.v о is supplied to block 6 to regulate the reference voltage (setpoint) of the compensation stabilizer and the rotation of the electric motor 9. The electric motor picks up speed and the welding head 7 starts to rotate around the pipe at a given speed.

After block 1 stops driving control voltage

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t, the current is automatically reduced and the welding head gradually slows down its movement over time, around the pipeline, the welding process ends.

In the absence of protective gas or water in the welding head cooling system, there is no control voltage at the 3rd inlet of the pressure block, and for this reason the welding arc from source 5 and electric motor from block 6 are not turned on. Thus, the welding cycle control block control device and affects the operation of the power source of the welding arc and electric drive heads.

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The control unit includes a rectifier made by a bridge circuit, a transistor filter that reduces the level of current ripples to power the stabilization unit 6, a delay line, a transistor key element, a coincidence circuit, high-speed electromagnetic relays, signal elements that allow the operator to visually observe the sequence of passage commands when welding the pipeline.

Claims (1)

Invention Formula The installation for controlling the welding process of the non-rotating pipe joints, containing a series-connected software unit, a functionally varying direction unit, a control unit for the electric motor and parameters of the welding arc, the input of which is connected to the output of the software unit, and the power supply. so that, in order to increase the reliability of the installation and the quality of the pipe welding joints, it contains, in series, a motor voltage stabilization unit, an overload protection unit and voltage drop, logic control unit and motor control unit, the second output of which is connected to the first input of the voltage stabilization unit of the electric motor, the second input of which is connected to the first output of the overload protection unit. Network login Vision 7 KSM.sy You) n) d2 VHOZ "" Cfm Output 1 P O / P Gecko From S5 VP-1 Fig.g entrance ffx-y FU9.U. % Xf one QxodS FIG L FIG. five