JPS5995427A - Method and apparatus for detecting surface of molten metal automatic feeder and breaking of wire - Google Patents

Abstract

PURPOSE:To obtain an apparatus having simple construction and easy fabrication and to detect surely the surface of a molten metal and the breaking of wire by providing a thermosensitive element in the neighborhood of a ladle and fetching a signal of this thermosensitive element to a thermometer having setting device. CONSTITUTION:A thermoelectric thermosensitive element 11 is attached to a holder 6 provided to a supporting arm 2 and a contact 12 is placed at a position capable of contacting with the surface of a molten metal 4. For example, the contact 12 is made of thin cast iron and has high sensitivity and thermoelectromotive force generating member made of highly sensitive chromel-alumel (CA) is used for the thermoelectric thermosensitive element 11. The element 11 is connected to a temperature indicator having a setting device 13 by a CA compensation lead wire 14 having a little smaller resistance for transmitting the thermoelectromotive force. This temperature indicator 13 is incorporated in e.g. a control board arranged near a dicast machine main body. The temperature indicator 13 adopts a burnout construction and the temperature is raised by the breaking of wire.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method and apparatus for detecting hot water level and disconnection in an automatic water heater in a molding machine such as a die casting man.

DESCRIPTION OF THE PREFERRED EMBODIMENTS A method and apparatus for detecting hot water level and wire breakage in a conventional automatic water heater will be described with reference to FIGS. 1 and 2.

In Fig. 1, the symbol 1 is a ladle.

It is rotatably attached to the lower end of the ladle support arm 2. The support arm 2 has a structure that scoops molten metal from the molten metal crucible shown in the figure and moves it to a hot water supply point of a growth apparatus not shown in the figure. The crucible is attached to a holding furnace 5 that maintains the temperature of a molten metal 4 of aluminum or the like, and is configured to maintain an appropriate temperature of the molten metal. A holder 6 is provided protruding from the support arm 2, and two electrodes 7 and 8 are attached to the holder 6.

Since the molten metal 4 is conductive, when the electrodes 7 and 8 come into contact with the molten metal surface, conduction occurs between the two electrodes, and the molten metal surface is detected. That is, when the electrodes 7 and 8 are electrically connected in FIG. 2, the hot water level detection relay 9 is activated and the lowering of the ladle 1 is stopped.

On the other hand, when the lead wires 7a+7b of the electrode 7 are disconnected,
The relay 10 for detecting wire breakage is activated and notifies the wire breakage accident.
Dangerous movement of the ladle 1 can be stopped.

However, if we adopt the structure described above.

There are two detection electrodes, which means that there are many parts per unit, and the mounting process requires a lot of man-hours for processing and assembly.

Further, the voltage applied to the electrode circuit needs to be about 24 volts so as to have little effect on the human body. This is because a portion of the lead wire 8a on the electrode 8 side uses the automatic water heater itself as a conductor. Therefore, when two workers touch the main body of the device, if the operating voltage is too high, it may lead to an electric shock accident.

On the other hand, as mentioned above, the lead wire 8a on the electrode 8 side uses the main body of the device as a conductor, so no disconnection will occur, but a disconnection will occur in the wiring from the automatic water heater to the relay 9 for detecting the hot water level. If that occurred.

There is a risk that relay 9 will not operate at all.

The present invention has been made to eliminate the above-mentioned drawbacks of the conventional technology.It has a simple structure, can reliably detect hot water level and disconnection, and is capable of detecting hot water level and disconnection in an automatic water heater that is easy to assemble. The present invention aims to provide a detection method and device.

FIG. 6 and subsequent figures are for explaining one embodiment of the present invention, and in FIG. 2, the same or corresponding parts as those in FIG.

In this embodiment, a thermoelectric temperature sensing element 11 is attached to a holder 6 provided on a support arm 2, and its contact 12 is placed at a position where it can come into contact with the surface of the molten metal 4. contact 1
For example, 2 is made of thin cast iron and has high sensitivity as the thermoelectric temperature sensing element 11.

For example, a thermoelectromotive force generating member made of highly sensitive chromel alumel (C!A) was used. The thermoelectric temperature sensing element 11 is.

As shown in FIG. 4, it is connected to the temperature indicator 13 with a setting device by a CA compensating conductor 14 having a slightly lower resistance for transmitting thermoelectromotive force. The temperature indicator 13 is installed, for example, in a control panel located near the main body of the die-casting machine.

The temperature indicator 13 has a pan-out structure.

When the wire breaks, the temperature will rise. That is,
The temperature indicator 13 includes a digital or analog display setting device 15 for detecting the hot water level and a setting device 16 for detecting disconnection. An input terminal 17 from the thermoelectric temperature sensing element 11, a comparator 18 for detecting the hot water level, and a setting device 19 for detecting disconnection are provided. Switch 20 for hot water level detection and switch 2 for disconnection detection
1 is provided, and the temperature sensed by the thermoelectric temperature sensing element 11 is sent to the setting device 15. When the temperature set by '1' and '6' is reached, each switch 20. Activate '21, switch 20
is switched, the lowering of ladle 1 is stopped, and switch 21 is turned on.
When the system switches, the automatic water heater will stop operating. 22 is a 100cm AC power supply.

Next, the operation of this embodiment configured as described above will be explained.

The curve indicated by the symbol A in FIG. 5 is a normal temperature curve,
What is indicated by symbol B is a pseudo temperature gradient curve within the thermometer when the temperature sensing element wiring is disconnected.

In FIG. 5, the normal hot water level detection set temperature is taken as point X, and when the temperature when the temperature sensing element 11 comes into contact with the molten metal 4 is at least 7 points 1, for example, 650° C. or more.

When the hot water level detection signal switch 20 is turned ON or N, a hot water level detection signal (electrical signal) is outputted to the temperature indicator 13, and the operation of the ladle 1 is stopped.

On the other hand, if the wire breakage detection set temperature is set to y, y', y"...2, for example, 800° C., and the wire of the temperature sensing element 11 is broken.

A pseudo temperature signal similar to when the maximum temperature is generated in the temperature indicator 13 is generated, the switch 21 is turned OFF, a disconnection detection signal (signal to electric) is output from the temperature indicator 13, and the operation of the ladle is stopped. can be done. In addition, Y, Y
A diagonal line that intersects with 'lY'+ indicates a temperature increase state before the temperature sensed by the temperature sensing element 11 starts to rise or when the wire is disconnected during the rise.

This is because the present embodiment is configured as described above.

Since the detection means is only the temperature sensing element 11, its installation is easy, requires less man-hours for assembly, and the structure can be simplified.

Further, the wiring of the temperature sensing element 11 has no exposed portion.

Not only is the wire less likely to be disconnected, but even if it does occur, the disconnection can be detected regardless of the location of the disconnection, and there is no need for a special circuit for detecting disconnection.

Note that by adding a temperature indicator to the temperature indicator with setting device 13, it becomes easier to control the temperature of the molten metal immediately before casting, and stable casting becomes possible.

If this temperature immediately before casting is fed back to the injection mechanism of the molding machine, it can be used to control the injection speed, pressure, etc., and a stable cast product can be obtained.

As is clear from the above description, according to the present invention, a temperature sensing element is provided near the ladle, a signal from the temperature sensing element is input to a thermometer with a setting device, and the temperature sensed by the temperature sensing element is set to a predetermined value. The structure uses a structure that can detect the hot water level and disconnection when the temperature exceeds the set temperature, so the number of two parts is small, the structure is simple and easy to assemble, and the hot water level can be detected reliably. and disconnection detection can be performed.

[Brief explanation of drawings]

1 and 2 are longitudinal cross-sectional views showing conventional structures and block diagrams of control circuits, and FIG. 6 and subsequent figures show an embodiment of the present invention. Control circuit diagram, 5th
The figure is a diagram showing the relationship between time and temperature. DESCRIPTION OF SYMBOLS 1... Ladle, 2... Support arm, 3... Crucible, 5... Holding furnace, 6... Holder, 11... Temperature sensing element, 12... Contact, 1...・Temperature indicator with setting device, 15.16... Setting device, 18.19... Comparator, 20... Switch for hot water level detection, 21... Switch for disconnection detection Patent applicant Ube Industries, Ltd. Company Figure 1 Figure 2 Figure 3 Figure 4

Claims (2)

[Claims] (1) A temperature sensing element is provided in conjunction with the ladle, the signal from this temperature sensing element is taken into a thermometer with a setting device, and the hot water level is detected when the temperature sensed by the temperature sensing element exceeds a predetermined set temperature. A method for detecting hot water level and wire breakage in an automatic water heater, characterized by detecting wire breakage and hot water level in an automatic water heater. (2) A temperature sensing element is fixed to the ladle support arm connected to the ladle, and a thermometer with a setting device is installed to capture the temperature signal when this temperature sensing element comes into contact with molten metal. The meter is equipped with a comparator that compares a preset setting value with the temperature signal from the temperature sensing element, and a detection means is installed to detect the hot water level and disconnection of the wiring to the temperature sensing element based on the comparison results. A hot water level and disconnection detection device for an automatic water heater, which is characterized by: