SU916083A1 - Apparatus for controlling liquid metal metering process - Google Patents

Description

The invention relates to the automation of foundry processes, in particular to the management of the dosing of liquid metals by electromagnetic pumps of alternating current.

Known dispenser containing a dispensing bath, a steeply ascending metal pipeline, a contact sensor for the start of pouring, electrically connected with a time relay that performs metering [1].

It is also known a device for controlling the batching process of a metal, consisting of a unit for measuring the amount of metal produced by a dose * tory made using a multiplying device, a root-extracting and integrating device (blocks) and a dosing control unit (control circuits, reference circuits, · metal appearance sensor at the exit of the metallotrakt, dose adjuster) G2].

The disadvantage of this device is that the dosing time is kor2

; It is corrected only when the supply voltage changes and does not depend on the level of the metal in the crucible and on the hydrostatic resistance of the metal tract, which significantly affects the accuracy of dosing.

The closest to the invention is the control unit of the dosing process, consisting of a force measuring unit acting on a metal ¹⁰ tal, which contains two measuring windings, a multiplying device, a voltage to frequency converter and a dosing control unit containing a dose setter, a key, a control circuit and connected to it sensors of the appearance of metal at the exit from the metal tract and the appearance of metal in the metal tract NW]. .

A disadvantage of the known device is that it does not take into account the change in hydrostatic resistance of the metal tract and the level of the metal in the tee! le at the time of issuance of the dose, which turned out to be 916683

It has a great influence on the accuracy of dosing, especially when casting doses larger than 1.5 kg.

The purpose of the invention is to improve the accuracy of dosing of liquid metals transported using a magnetodynamic type pump.

This goal is achieved by the fact that the proposed device contains a unit for measuring the force acting on 1 metal, consisting of two measuring windings, a multiplying unit and a voltage-to-frequency converter, a control unit for the dosing process, consisting of a key, the first ι reversing pulse counter, a control circuit and sensors connected to it of the presence of metal in the metal "tract and the presence of metal at the outlet of the metal tract, and the control unit; The process of dosing additionally contains a second reversing counter, the output of which is connected to the control input of the voltage-to-frequency converter via the key and the control-; The meter input is connected to a metal volume sensor in the mold.

FIG. 1 shows a block diagram of the proposed device; in fig. 2 - placement of measuring ι windings and metal presence sensors on the metal tract.

The device consists of a unit 1 for measuring the force acting on the metal in the core of the metering pump, and a unit 2 for controlling the dosing process, which turns off the power supply to the transformer h. The unit includes a current 4 winding placed on the metal path outside the core, measuring ₄ winding 5, multiplying block 6, voltage-to-frequency converter 7 (FNP). The dosing process control unit 2 consists of a control circuit 8, a first reversible counter ₄ 9 pulses, a second reversible counter 10 pulses, a metal appearance sensor 11 at the exit of metal trap; ha, a metal presence sensor 12 in the metal tract 13-15 and a metal volume sensor 16 in form.

The device works as follows.

When the magnetodynamic pump is filled with metal and switched to storage mode, winding 4, which is the winding of the current transformer (primary - liquid metal), is induced by EMF

1k, proportional to the current induced by the liquid metal inductors 17 (Fig. 2). When you turn on the trans. Matora 3 (pouring mode) creates a magnetic field, interacting with a current induced in a liquid metal and causing the appearance of an electromagnetic force, under the action of which the liquid metal enters the metal receiver. At the same time in the windings 5 induced EMF and ₂ . - proportional to the magnetic field. The voltage is 1C and is fed to the inputs of the multiplying device 6, at the output of which we receive a signal proportional to the electromagnetic force acting on the metal in the active zone of the pump. This signal is fed to the input of the FNC 7, at the output of which we receive pulses that follow with a frequency proportional to the electromagnetic force acting on the metal. When the electromagnetic pump is turned on in the pouring mode, the metal rises along the metal tract under the action of electromagnetic force. When the front of the metal jet reaches the control zone of the sensor 12 (time instant), a signal is sent to the control circuit (for example, in the form of a pulse). The control circuit 8 opens the key 13 and on the counting input of the first reversible counter (DMC)

9 there are pulses from the output of the NPS 7.

When reaching the front of the metal stream of the sensor 11 (time

The control circuit 8 sends a signal to the control inputs of the first control panel 9 · The distance between the sensors 11 and 12 is constant.

At time xd. the key 14 is opened and the conversion coefficient of the PNCh7 varies in proportion to the number N, depending on the desired dose set by the operator. During the time ai = ίχ ~ Ts at the control input of the PSI 9 there is no signal, the counter 9 operates in the recording (summing) mode of pulses. When a signal arrives at the control input of the SRCh 9 (Hy.), The counter switches from the recording mode to the mode of writing off (subtracting) pulses. When the counter 9 takes the zero state (all pulses are written off), it sends a signal to the control circuit 8, which disconnects the transformer '3 and thus stops pouring (£ _δ ). After issuing the dose (-L ₃ ), the key 15 is opened and a signal is sent to the counting input of the second SPM 10.

5 916083

in the form of pulses, which is subtracted or added together depending on the mode of operation of the PSD counter 10. If the control input of the second PSU 10 receives a signal from a metal volume sensor 5 in a mold 16, for example, from a contact sensor installed in a die, it means that the dose more than the norm, the PSD 10 switches to the pulse subtraction mode. The number, 0 lo, recorded in the SDCU 10, will become Ν-ό. Thus, the next dose will be reduced by changing the conversion factor of the FNP 7 proportional to the number Ν-a. If at the control-15 of the second input of the SRCh 10 there is no signal (which means the dose is less than the norm), the number Ν + a (summation mode) will be recorded in the counter and the next dose will be increased. The number a varies from 20 to dosage additionally in the range of 0.5 + 1% of the dose.

When changing hydrostatic

resistance of the metallotrakt or the level of the metal in the crucible will change the speed of the metal and, therefore, Δΐ <.

25

Thus, the proposed device for controlling the dosing process can improve the accuracy

dosing due to the correction of the next 30 mini and zinc alloys in the car

dose, i.e. take into account the change in hydrostatic resistance of the metallotrakt and the level of the metal in the crucible during

The above advantages make it possible to improve dosing accuracy.

by 20-30%.

35

Claims (1)

A device for controlling the process of dosing a liquid metal is electromagnetic, ·: a dosing device containing a unit for measuring the force acting on a metal, consisting of two measuring windings, a multiplying unit and a voltage-to-frequency converter, a control unit for dosing press consisting of a key, a first reversible counter pulses, control circuits and sensors of metal presence in the metal tracts connected to it, the presence of metal at the exit from the metal tract, characterized in that, in order to increase the For metering of liquid metals transported using a magnetodynamic type pump, the unit will control the second reversible pulse counter, the output of which is connected to the control input of the voltage-to-frequency converter via a key, and the control input of the counter is connected to the volume-sensing metal sensor.