JPH08122124A - Apparatus for measuring surface level of molten metal - Google Patents

Abstract

PURPOSE: To provide an apparatus for measuring the surface level of molten metal, which can automatically measure the surface level accurately without much time and labor. CONSTITUTION: In this apparatus, in which an electrode rod 15 is lowered, the contact of the electrode rod 15 with the surface of a molten metal 45 is detected by the change in electric resistance at the contact, the moving amount from a reference position to the surface level is measured with a measuring means 17, and the height of the surface 45 of the molten metal 45 is measured based on the output value of the measuring means 17, a zero-point sensor 16, which detects the electrode rod 15 including the metal that is attached to the lower end of the rod, is provided at the intermediate position of the lowering of the electrode rod 15, and the measurement of the measuring means 17 is started based on the output of the zero-point sensor 16.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a molten metal level measuring device for automatically measuring a molten metal level such as molten zinc or molten solder (referred to as liquid level height). .

[0002]

2. Description of the Related Art Hot-dip galvanizing is carried out by putting a material to be plated in hot-dip zinc in a plating pot for a predetermined time. However, the amount of hot-dip zinc decreases when repeated plating is performed. At the beginning and at the end of the plating operation, the amount of molten zinc is monitored by measuring its level. The molten metal surface level measurement according to the conventional example is shown in FIG.
As shown in Fig. 1, a hook collar 1 provided around the plating hook 100
01, slide arm 102, slide arm 10
2 Measuring stick 103 for reading the movement and its pedestal 10
4, a molten metal level measuring instrument 105 is placed, and after waiting for the molten metal to stand still, the oxide film 106 on the surface is scraped off, and the slide arm 102 is lowered and fixed at a position where its tip is brought into contact with the molten metal surface 107, The molten zinc surface 107 was read from the ruler rod 103.

[0003]

However, in the above-mentioned apparatus 105, the slide arm 102 has the molten metal surface 107.
Since the operator visually determines whether or not the user has touched, there is an individual difference (for example, about ± 7 mm) and accurate measurement (±
1 mm) is difficult and more time-consuming. Further, molten zinc may be attached to the lower end of the slide arm 102, which may cause an error, and further, ammonium chloride or the like, which is added to the molten zinc plating solution as a chemical agent, may be attached to the surface of the ruler rod 103. In this case, there is a problem that it becomes difficult to move the slide arm 102. Such a problem has been a common problem not only when measuring molten zinc but also when measuring the level of molten solder or the like. The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a molten metal level measuring device capable of accurately and automatically measuring the level of a molten metal.

[0004]

A method according to the above-mentioned object.
The molten metal level measuring device described above lowers the electrode rod, detects contact of the electrode rod with the molten metal level by a change in its electrical resistance, and moves from the reference position to the molten level. In a molten metal level measuring device for measuring the amount by a measuring means and measuring the molten metal height based on the output value of the measuring means, the electrode rod is placed at a descending intermediate position of the electrode rod. Is provided at the lower end of the sensor including a metal attached to the lower end thereof, and the measurement of the measuring means is started by the output of the zero sensor. And
The molten metal level measuring device according to claim 2 is the device according to claim 1, wherein resetting is performed when the first output value of the measuring means coincides with the input signal of the measurement start height position previously input. A circuit is provided and the resetting position is used as the reference position, the measuring means measures the height of the molten metal surface, and the measured value is displayed.

[0005]

In the molten metal level measuring device according to the first and second aspects, the zero point sensor for detecting the electrode rod together with the metal attached to the lower end thereof is provided, and the output value is used as the start signal of the measuring means. Even when the molten metal adheres to the lower part of the electrode rod and is solidified by being used a plurality of times and the electrode becomes substantially long, the substantial lower end of the electrode is always detected. On the other hand, when the molten metal level is detected, when the metal is attached to the lower end of the electrode rod, the change in electrical resistance is detected when the lower end of the attached metal contacts the molten metal level. It is possible to accurately measure the molten metal surface regardless of whether the metal adheres to the electrode rod. In particular, claim 2
In the molten metal level measuring device described above, since it is arranged to be reset when the first output value of the measuring means coincides with the input signal of the measurement start height position inputted in advance, it is arranged in the device. By inputting the height of the zero point sensor from the reference surface (for example, the bottom surface of the apparatus) as the measurement start height position, the output actually desired by the measurer can be displayed.

[0006]

Embodiments of the present invention will now be described with reference to the accompanying drawings to provide an understanding of the present invention. FIG. 1 is a schematic explanatory view of a molten metal level measuring apparatus according to an embodiment of the present invention, FIGS. 2 and 3 are the same electric circuit diagrams, and FIG. 4 is a graph showing the measurement results.

As shown in FIG. 1, a molten metal level measuring apparatus 10 according to an embodiment of the present invention is screwed to a male screw 12 driven by a motor 11 having a reduction gear at the upper portion thereof. Electrode rod 1 that moves up and down by female screw 13
5, a zero-point sensor 16 through which the electrode rod 15 is inserted, a rotary encoder 17 which is an example of a measuring means for measuring the rotation amount of the male screw 12, a controller 18 for these, and a display unit 1.
9 and a battery 20 which is a rechargeable power source, and an outer case 21 made of stainless steel. These will be described in detail below.

A lower portion of the male screw 12 is supported by a bearing (not shown), and a motor 11 with a speed reducer is connected to the upper portion thereof. A large gear 17a is provided in the upper middle of the male screw 12.
Is provided, and the large encoder 17a is provided with a rotary encoder 17
The small gear 17b attached to the input shaft of is meshed. A female screw 13 is screwed onto the male screw 12, and this female screw 1
A horizontal support member 22 is attached to the horizontal support member 2
An electrode rod 15 is attached to the tip of No.2. The electrode rod 15 is made of a stainless steel rod and is attached to the horizontal support member 22 via an insulating material. The horizontal support member 2
2 is provided with a guide groove 22a at an intermediate portion thereof, and the male screw 1
The horizontal support member 22 is prevented from turning by the rotation of 2. Therefore, when the motor 11 with a speed reducer is rotated, the male screw 12 is rotated to move the electrode rod 15 up and down, and the amount of movement thereof is electrically detected by the rotary encoder 17.

A zero point sensor 16 is provided in the lower part so as to be aligned with the axis of the electrode rod 15. The zero point sensor 16 is a penetration type proximity sensor, and a conductor such as a metal inside the zero point sensor 16 enters the zero point sensor 16. The impedance changes, and the start of passage of the electrode rod 15 is detected. An upper limit switch 23 is provided above the electrode rod 15,
It is designed to detect that the electrode rod 15 has come out of the zero point sensor 16 and is at the upper standby position.

The electric circuits of the control device 18, the display 19 and the battery 20 are shown in FIGS.
To R8 and a sequence circuit having transistors Tr1 to Tr4, a battery 20, a power switch 25
And a fuse 26 and an indicator lamp 27 to indicate an operating state.
33 and 33a are provided. The operation of the circuit will be described below. This molten metal level measuring device 10
With the start switch 34 pressed,
The relay R1 is excited, the motor 11 with a speed reducer rotates normally, and the electrode rod 15 at the upper limit position descends. Then, when the electrode rod 15 comes into contact with the molten metal surface, the transistor Tr2 is actuated, the relay R7 is actuated, and thereby the relay R2 is actuated to short-circuit the speed reducer-equipped motor 11, thereby applying a brake. .

In this state, the timer circuit (counting about 1 to 2 seconds) formed by the resistor 35, the capacitor 36, and the transistor Tr1 is activated, which activates the relays R3, R4, and the motor 11 with a reducer. Will be reversed and the electrode rod 15 will rise. Thereafter, the electrode rod 15 actuates the upper limit switch 23 to actuate the relay R6, thereby turning off the relay R1 and turning off the motor 11 with a reducer to stop the electrode rod 15 from rising. The small-capacity capacitor 37 provided on the base side of the transistor Tr2 prevents malfunction due to noise or the like.

While the electrode rod 15 is performing the above operation,
When the zero-point sensor 16 detects the tip of the electrode rod 15, the relay R5 is actuated and the preset input (A, B) terminals of the preset counter 39, which is an example of a measuring means, is momentarily closed by the capacitor 38, and the preset counter 39. Is reset once. Since the reset of the preset counter 39 is instantaneous, the preset counter 39 then starts counting the output of the rotary encoder 17 from 0 as the electrode rod 15 descends. As a result, even if metal adheres to the lower end of the electrode rod 15, the preset counter 39 starts counting with the lowest part of the adhered metal as a reference.

After the rotary encoder 17 starts measurement, when the pedestal height value H, which is a measurement start height position input by a digital switch (not shown), and the count signal of the preset counter 39 match, the preset counter 39 matches. Emits output 40, actuating relay R8. When the relay R8 is activated, the transistor T is turned on again.
r4 instantly operates and resets the preset counter 39. When the coincidence output 40 is output, the relay R8
Since it holds by itself, the reset signal is not issued even if there is a coincidence output again.

By the above operation, as shown in FIG.
The lower end of the pedestal 41 of the molten metal level measuring device 10,
That is, the preset counter 39 starts counting from the upper end position of the pot collar 42 of the plating pot. When the electrode rod 15 contacts the surface of the molten metal, the relays R7, R
2 operates, the prohibition input is given to the preset counter 39, the operation of the preset counter 39 is stopped, and the measured value is displayed on the display unit 19. As a result, the exact height of the required molten metal surface can be obtained. In addition,
If you want to cancel the measurement on the way, cancel button 4
When 3 is pressed, the motor 11 with a speed reducer reversely rotates, the measurement is stopped, and the electrode rod 15 returns to the upper limit position.

These components are housed in an outer case 21 having a handle 21a on the upper portion thereof, and a heat insulating material 44 is provided at a portion where the electrode rod 15 projects, so that the radiant heat from the molten metal 45 has an effect. Is reduced. 4
6 indicates a charging input terminal. The measurement result of the molten metal level measuring apparatus 10 is shown in FIG. 4, and it can be seen that the value substantially agrees with the value actually measured by the micrometer. Although the proximity sensor is used as the zero-point sensor in the above-described embodiment, an optical sensor can also be used.

[0016]

As is apparent from the above description, the molten metal level measuring apparatus according to the first and second aspects of the present invention considers the metal adhering to the lower portion of the electrode rod, and determines the lowering position of the electrode rod. Since the detection is performed, the position of the molten metal surface can be accurately measured even if the molten metal adheres to the lower end of the electrode rod after repeated use. Particularly, in the molten metal level measuring device according to the second aspect, since the measured height position is input and is output in consideration of this signal, the desired height to the molten metal level should be directly displayed. You can

[Brief description of drawings]

FIG. 1 is a schematic explanatory diagram of a molten metal level measuring apparatus according to an embodiment of the present invention.

FIG. 2 is the same electric circuit diagram.

FIG. 3 is the same electric circuit diagram.

FIG. 4 is a graph showing measurement results.

FIG. 5 is an explanatory diagram of a molten metal level measuring apparatus according to a conventional example.

[Explanation of symbols]

 10 Molten metal level measuring device 11 Motor with reduction gear 12 Male screw 13 Female screw 15 Electrode rod 16 Zero point sensor 17 Rotary encoder 17a Large gear 17b Small gear 18 Control device 19 Indicator 20 Battery 21 Exterior case 21a Handle 22 Horizontal support member 23 Upper limit switch 25 Power switch 26 Fuse 27 Indicator lamp 28 Indicator lamp 29 Indicator lamp 30 Indicator lamp 31 Indicator lamp 32 Indicator lamp 33 Indicator lamp 33a Indicator lamp 34 Start switch 35 Resistor 36 Capacitor 37 Capacitor 38 Capacitor 39 Preset counter 40 Match output 40 41 Pedestal 42 Kamaba 43 Cancel Button 44 Insulation Material 45 Molten Metal 46 Charge Input Terminal

Claims (2)

[Claims] 1. The electrode rod is lowered, and the contact of the electrode rod with the molten metal surface is detected by a change in its electrical resistance, and the movement amount from a reference position to the molten metal surface is measured by a measuring means. A molten metal level measuring device for measuring the molten metal height based on the output value of the measuring means, wherein the electrode rod is attached to its lower end at the descending intermediate position of the electrode rod. A molten metal level measuring device, characterized in that a zero point sensor for detecting is also provided, and the measurement of the measuring means is started by the output of the zero point sensor. 2. A reset circuit is provided, which resets when the first output value of the measuring means coincides with the input signal of the measurement start height position input in advance, and the measuring means uses the reset position as the reference position. The molten metal level measuring apparatus according to claim 1, wherein the molten metal height is measured and the measured value is displayed.