SU1154039A1 - Apparatus for metering melt material - Google Patents

Abstract

A DEVICE FOR DOSING A MOLTED METAL containing a crucible for a melt, an electromagnetic pump, a monitoring pipeline, a chamber, a safety pipeline, a starter, a metal level sensor and a time relay, which lack TeMj, to improve performance. . equipped with a power amplifier, a pre-amplifier and a relay element, the output of the metal level sensor connected to the preamplifier input, the first output of which is connected to the first input of the power amplifier, the output of which is connected to an electromagnetic pump, the second input of the power amplifier connected to the first output of the relay element, the input of which is connected to the second output of the preamplifier, the second output of the relay element - to the input of the time relay, the output of which is connected to the input of the actuator, the output D which is connected to the third input of the power amplifier and an electromagnetic pump.

Description

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The invention relates to the automation of casting processes, and the name refers to the dosing of liquid metals by electromagnetic and magnetodynamic pumps.

A device for metering liquid metals is known, comprising a crucible for the melt, a magnetodynamic pump, a drain metal pipeline ill,

When dosing over time, errors arise related to the change in the level of the metal in the crucible, possible colourations of the supply voltage in the network, overgrowth of the metal pipe with oxides, as well as the presence of gaps at the junction of the metal pipe with the channel mouth.

The closest to the invention to the technical essence is a molten metal zincing device containing a melt crucible, an electromagnetic pump, a monitoring pipeline, a chamber, a safety pipeline, a starter, a metal level sensor and a time relay 2},

The operation of the device is based on a slow increase in power. pump, which reduces performance.

The purpose of the invention is to increase productivity.

The goal is achieved by the fact that a device for metering molten metal containing a crucible for a melt, an electromagnetic pump, a monitoring pipeline, a chamber, a safety pipeline, a starter, a metal level sensor and a time relay are equipped with a booster amplifier, a preamplifier and a relay element, and the sensor output The metal level is connected to the input of the preamplifier, the first VIDEO of which is connected to the first input of the power amplifier, the output of which is connected to the electromagnetic The secondary input of the power amplifier is connected to the first output of the relay element, the input of which is connected to the second output of the preamplifier. The second output of the relay element is connected to the input of the time relay, the output of which is connected to the input of the actuator, the output of which is connected to the third input.

power amplifier and electromagnetic pump.

A metal level sensor, used as a photodiode placed in the focal plane of the lens, is mounted above the hole of the monitoring pipeline.

To ensure time dosing, a pump start and stop device, time relays associated with a relay element and a pump are introduced.

The outlet pipe is connected to the outlet: / opening of the control piping.

FIG. t is a block diagram of a device for metering molten metal; in fig. 2 is a circuit diagram of a preamplifier with a photodiode of a metal level sensor in FIG. 3 is a schematic diagram of a relay element; FIG. 4 is a circuit diagram of a power amplifier.

A device for metering molten metal contains a crucible with a magnetodynamic pump 2, including an inductor 3, an electromagnet 4, channel 5, into the mouth of which 6 a monitoring pipeline 7 is inserted, which is connected in the upper part to the safety pipe 8 by means of chamber 9. To the discharge hole c, located below the working level 8, which controls the pipeline 7, the directions 10 of the pipe 10 are connected.

In the upper part of the monitoring pipeline 7, a metal level sensor 11 is installed, comprising a lens 12, a pipe 13, a photodiode 14 installed in the focal plane of the lens 12. To implement negative feedback, the device is equipped with a preamplifier 15, a power amplifier 16, a relay element 17. For time metering, time relays 18, starter 19, for example, type PA-512 with Start and Stop buttons, are entered into the device. The time relay can be of type VL-27U4.

Preamplifier 15 is a DC amplifier assembled on four transistors in a differential circuit (FIG. 2). The input of the preamplifier 15 is the photodiode 14 of the metal level sensor 11, connected to the base circuit of the transistor VT1. To compensate and dark resistance of the photodiode UD1 in the circuit of the base of transistor VT4, the photodiode UD2 is turned on. The voltage taken from the part of the resistance P2 serves as the first output of the pre-amplifier, and the potential difference across the collectors of the transistors T2 and TZ is the second output of the pre-amplifier.

The relay element (Fig. 3) is a DC amplifier on a transistor assembled according to a common emitter circuit, the collector circuit of which includes the relay coil P1. The normally closed contacts of the relay P1 are the first output of the relay element. The second output of the relay element are the contacts of the relay P2, the winding of which is connected in series with the contacts of the relay P1 and the time relay (the power supply of the time relay is not shown)

As a power amplifier, a magnetic amplifier was used that was built in a differential circuit (Fig. 4).

A device for metering molten metal works as follows.

Using the start and stop device 19, the magnetodynamic pump 2 is turned on through the power amplifier 16 and is supplied with power (not shown) to the amplifiers 15, 16 and the relay element 17; At this point in time, the metal mirror in the monitoring pipeline 7, being the source of infrared radiation, is at a maximum distance from the lens 12 of the metal sensor 11. Pump 2 is turned on for maximum power through negative feedback: metal surface in a controlled pipeline as a source of radiation Photodiode 14 of a sensor It’s level of a metal as a converter of radiation intensity to a proportional amount of current flowing through it, preamplifier 15, power amplifier 16, electromagnet 4 of a magnetodynamic pump 2

With existing negative feedback, pump power is inversely proportional to the square of the distance between the metal mirror.

in the control pipeline 7 and lens. 12 gauge and metal level.

Therefore, as the molten metal in the control line 7 approaches the lens 12 of the metal level sensor 11, the pump power is limited. Thus, maximum speed is ensured.

lifting the metal in the control pipeline 7 with its automatic limitation when the metal mirror approaches the working level 6, which eliminates the harmful effect of the inertial period of the metal movement.

At the intersection of the molten metal of the working level, the voltage at the second output of the preamplifier 15 reaches the value

actuation of the relay element 17, as a result of which the pump power is discretely limited by the second negative feedback: the radiation of a metal mirror

in the control pipeline 7, metal level sensor 11, preamplifier 15, relay element 17, power amplifier 16, electromagnet 4 magnetodynamic

pump 2. The overpressure of the magnetodynamic pump 2 decreases sharply. By inertia, the metal rises somewhat up to level C, after which, lowering down, again

crosses the operating level 8, the relay element 17 under the influence of the changed voltage from the second code of the preamplifier 15 becomes in the initial state

break negative feedback. The power of pump 2 increases. By inertia the metal descends somewhat down to the level ei and again rises upwards, crossing

working level Again, under the influence of an increase in the signal from the second output of the preamplifier 15, the relay element 17 is triggered, discretely forming negative feedback.

The power of pump 2 decreases, the overflow pressure at its outlet drops, the cycle repeats.

Discretely limiting the pump power during the passage of the metal mirror through the working level 6, in the control pipeline 7, the second “is negative; feedback

It makes it possible to maximize the effect of the first negative feedback, which is aimed at reducing the time of metal lifting, except for TorOj, with its help over the above-said hole, it is maintained at a constant level of the metal. The amplitude and frequency of oscillations of the metal mirror in the controlled pipeline 7 depends on the parameters of the pump and the feedback, thus the level of the metal can be maintained with any predetermined accuracy by changing the feedback parameters.

When the device is operated to doze the molten metal over time, the signal from the second output of the relay element 17 is fed to a time relay 18, which, after the set time has elapsed, sends a signal to the starter 19 which disconnects the pump from the mains. The amount of metal poured through the outlet a will be proportional to the pump time j5a6oTM.

Compared with dosing in terms of level, dosing in time is characterized by higher productivity, since in the latter case there are no transients associated with the establishment of the metal level in the injection chamber.

The use of a metal level sensor with two negative feedbacks allows an increase in productivity due to the shortening of the time it takes for the metal to rise to the bulge hole. In addition, in the device, thanks to new connections and elements, a single sensor was used, which was removed from the high temperature zone, which simplifies the design of the monitoring pipeline, and increases the reliability of the device as a whole.

Claims (1)

DEVICE FOR DISPENSING molten metal comprising a crucible for molten metal, an electromagnetic pump controlling conduit, the chamber, the safety line, the starter, the metal level sensor th time relays, of Whitlock ichayuscheesya _those} that, in order povvveniya performance, it is provided with a power amplifier, preliminary an amplifier and a relay element, and the output of the metal level sensor is connected to the input of the pre-amplifier, the first output of which is connected to the first input of the power amplifier, the output of which is dynamo with an electromagnetic pump, the second input of the power amplifier is connected to the first output of the relay element, the input of which is connected to the second output of the pre-amplifier, the second output of the relay element is connected to the input of the time relay, the output of which is connected to the input of the starter, the output of which is connected to the third input of the power amplifier and electromagnetic pump. 'бё0НП’Ж