JPH0220924B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a sampling lance for collecting a sample from molten metal.

The level of molten metal in the ladle must be known as accurately as possible for several reasons. One reason is that when withdrawing a specimen from the molten metal, it is necessary to know that the specimen removal device is positioned sufficiently deep in the molten metal to be sampled. .
Another reason is that when oxygen gas is blown into molten metal to refine it, in order to maximize its effect, the oxygen gas is blown at a certain height above the molten metal liquid level. This means that it must be done.

In the case of oxygen gas injection, the distance between the opening of the oxygen gas lance and the metal level, ie the level of the molten metal below the slag layer, must not vary by more than a few centimeters in practice. However, to date there is no method that can be used satisfactorily to determine the level of molten metal with acceptable accuracy, and for this reason a derivative variation of as much as 50 cm must be allowed. Ta. This means that the fluctuations caused in the composition of the molten metal had to be compensated for by appropriate means. This further unnecessarily prolonged the residence time in the chill mold, thus increasing costs.

Although the invention will be described below in the context of a sampling lance, it will be clear to those skilled in the art how the signals obtained from the sensor can also be used for several other purposes. I think there is. That is, the signal obtained by sampling can be used to determine how deep the oxygen lance must be withdrawn into the molten metal for oxygen gas injection. Note that a separate level indicator can be used for both sample removal and oxygen gas insufflation.

In the illustrative embodiment, one inductive sensor is used. Capacitive sensors may be advantageous in certain applications. Also, in some applications it may be appropriate to use two sensors arranged in series. For example, the more the signal is received from the slug layer, the more the slug layer
This is the case when there is a suspicion that there is a thick layer within the metal. In such cases, the difference in the signals from the two sensors clearly indicates where the molten metal level lies.

There are many problems associated with extracting specimens from molten metal, especially molten metal in a ladle. Among these issues are ensuring that the sampler reaches a sufficient depth in the molten metal so that a representative sample is obtained when the sampler is withdrawn; The sample remover remains in the molten metal for a period of time sufficient to fill the removal mold, but insufficient for the specimen to flow out without solidifying when the sample remover is withdrawn. There is a problem of how to ensure that it is maintained.

It should be noted that other devices, such as measuring devices for determining the activity and temperature of the oxygen in the molten metal, and also for determining the time during which such device is submerged, may be used towards or from the molten metal. Similar problems exist with respect to determining the level of liquid to be withdrawn.

On the surface of molten metal, the specimen extractor must always plunge into it without hindrance.
There is a suspended layer of slag and other contaminants. Below this layer, there follows a relatively thin, extremely hot melt zone, below which lies the portion of the melt that is usually desired for extracting the specimen.

It should be noted that disposable and multi-use specimen removal devices are known which, in some cases with slight modification, can be used in conjunction with the lance of the present invention. Therefore, the specimen retrieval device itself is not a subject of the present invention. Furthermore, other devices which may be used for drawing towards and into molten metal by means of the device according to the invention do not form part of the invention.

To insert the specimen retrieval device into the molten metal,
A lance is used, usually in the form of a straight or curved steel tube, to which a sampling device is attached at one end. The sampling device manually or by means of a winding device moves the molten metal to a location deemed sufficient to remove a representative sample of the molten metal by the person performing the extraction. It is unloaded. In this regard, the extraction mold is filled and the specimen is
It is important to maintain the sampler in the molten metal long enough for it to harden enough to remain therein. If the sampler is kept in the melt for too long, the specimen will heat up to such an extent that it will flow from the mold when the sampler is withdrawn.

Because it is practically impossible to determine the thickness of the slag layer and thus the level in the ladle at which the surface of the melt lies, it is often difficult to obtain representative specimens. Become. Therefore, attempts have been made to solve the above problem by using thermoelements that are related to the specimen. The idea was to provide a clear indication of the molten metal level in the hot zone below the slag layer. However, this attempt has been unsuccessful primarily because deposits have adhered to the thermo-element and caused inaccurate readings. In that sense, no method has been found to solve the problem with deposits.

The purpose of the present invention is to be able to be reused many times and to
It is an object of the present invention to provide a sample collection lance that is inexpensive to reuse, and furthermore, to provide a sample collection lance that can collect a sample at a desired depth in molten metal. It is in.

In order to achieve this objective, the sample collection lance of the present invention has the following configuration. That is,
A sampling lance inserted into molten metal in a ladle or the like, which has a specimen extractor at its lower end for collecting a specimen at a certain depth in the molten metal. in the sampling lance, in order to determine the depth of the sampling lance in the molten metal, a non-contact probe is placed inside the lance tube of the sampling lance at a predetermined distance above the sample extractor. installing a type of sensor connected to the sensor;
and providing a conductor extending through the lance tube, coupled in a manner known per se to the sensor and processing signals from the sensor input through the conductor. providing an external device, closing a lower part of the lance tube to prevent molten metal from flowing into the interior of the lance tube, providing a hole in a wall of the lance tube facing the sensor, and having heat resistance; and a sheath made of an electrically non-conducting material is provided around the lance tube, and the sheath completely covers the hole so that the sensor does not come into contact with the molten metal. This is a lance for collecting specimens.

According to the sampling lance of the present invention having such a configuration, the depth of the sample extractor in the molten metal can be accurately determined by the sensor, so that the molten metal at a desired depth can be used as a sample. Not only can the sample collection lance of the present invention be used to collect specimens, but it can also be reused many times by simply replacing the sheath, thereby reducing usage costs.

Next, with reference to the drawings showing embodiments of the present invention,
The present invention will now be explained in more detail.

In the illustrated embodiment, a non-contact inductive sensor 1 is positioned within a lance 20 made of steel tubing, and a sample extractor is mounted near the end of said lance. The sensor 1 is, for example, a screw 22
is mounted on the rod 21. In order to keep the sensor 1 in the desired position in the lance tube 20, the rod 21 is bent and its end is fixed to the lance tube 20, for example by a rivet 23. However, the above mounting is performed so that the outer surface of the lance 20 is smooth.

The sensor 1 is positioned directly opposite the bore 24 of the lance tube 20. This hole is for sensor 1
However, the lance tube 20 is sufficiently large so that it is not affected by the molten metal inside the lance tube 20.

The sensor 1 is radially adjustable so that it can occupy its position in the lance tube at different distances from the bore 24. In this way, the degree of sensing can be easily varied since the actuating projection is extended to different distances from the lance according to the adjustment. This adjustment is done with screw 2
2 can be applied.

The sensitivity of the sensor 1 can also be changed electrically. In some cases, when the slag on the molten metal contains enough metal to affect the sensor, it can also be a reason for reducing the sensitivity.

Leading out from the sensor are a number of conductors 25, which are suitably connected to the device as described below.

If a specimen extractor 26 is used, it is positioned over the end of the lance 20, together with a sensate sheath 27. The sheath 27 can preferably be made of paper material and consists of several layers glued together by a suitable bonding agent, such as sodium silicate or resin, the thickness of which is between 10 and 10 mm. It is set to 15mm. The above thicknesses may vary depending on the application; the above values are only suitable for those most commonly used.

The length of the sheath 27 is such that it covers the hole 24 with sufficient margin, and the specimen extractor 26 is in a constant relationship with the sensor 1 when mounted directly on the lance 20. The mold is positioned within the mold.

The material inside the sheath 27 is non-conductive so as not to affect the sensor 1. This material is also designed to prevent molten metal from adhering to it.
In addition to paper, it can also be made of ceramic fiber, for example. When paper is used as a material, boiling occurs mainly in the sheath material when it is lowered into the melt, and this boiling tends to have the effect of preventing deposits from adhering to the sheath. .

The sensor 1 is provided with an actuating projection that projects generally transversely from the lance 20. This means that when the sampler 26 is withdrawn into the melt, this sensor will give the desired signal under the action of the molten metal. It has been found that the sensor is rarely affected by the slag layer.

The functional aspects of the present invention will become clear from the operation of the electric device described below. However, it should be understood that a variety of designs are possible, and what is described above is merely illustrative of one suitable design.

Regardless of whether the specimen extractor is disposable, multi-use, or some other device is used, the fundamental novelty of the present invention is that it It will be clear to the person skilled in the art that the sensor can be used and that this is achieved by holding the sensor within the lance itself. think. The hole in the lance required to activate the sensor is sufficiently protected by the sheath, and the configuration of the sheath provides sufficient protection without negatively impacting the detection capability of the sensor. It's amazing that it exists. For this reason, it is entirely possible to separate the device and cover for the sensor without prejudice to the spirit of the invention itself.

The "preparation for sample removal" signal light is illuminated when the "shutter or gate contact" 3 is closed, and at the same time a 24V potential is applied to the amplification unit 2 for the non-contact inductive sensor 1.

The signal from the non-contact induction sensor 1 is assumed to be 24V when the sensor detects molten metal, and 0V when the sensor does not detect molten metal.

To connect the drive motor for withdrawing the specimen extractor, the activation button 4 is pressed and the relay 5 for self-holding the relay contacts is activated. The relay 5 is energized from the power supply phase 10 via a contact arm 72 which rests against the contact 75.

When the inductive sensor 1 is withdrawn and reaches the molten metal, a potential of 24 V is created on the connection 71, which causes the relay 7 to switch into a self-holding state. At the same time, the "specimen retrieval ready" signal light goes out. When the non-contact type sensor 1 detects molten metal, the relay 7 is energized and the relay contact 73 is switched from position 75 to position 74, thereby cutting off the current supplied to the coil of the relay 5. ,
The self-holding state of relay 5 stops. Switching contact arm 73 to position 74 applies voltage to timer 78, causing timer 78 to be triggered. After a certain period of time, the timer contacts 80 are closed, energizing the motor relay 6 and causing the drive motor to "climb" to lift the specimen extractor from the molten metal.
Switch to the position. A limit switch 11 is provided to limit the upward movement in this case. An emergency hoisting contact is provided which provides a bypass to the timer contact 80 in the event of a failure in the sample remover, so that the sample remover is activated before the timer contact 80 is actuated. Must be removed from the melt. Emergency evacuation relay 1
The arcuate contact 121 in 2 is
At the same time as cutting off the current to the "dropping" relay 5,
Relay 6 for salvage is energized.

When the sampler is being withdrawn from the melt, the potential on connection 71 is switched from 24V to 0V. When the gate contact 3 is opened, the self-holding of the relay 7 is broken, so that the "specimen retrieval preparation" signal light is turned on and the timer 8 is reset. This means that a new sample extraction order operation can be performed.

In the device of the invention described above, two sensors can be provided one after the other in the lance. An indication of the thickness of the slag layer can also be obtained by comparing both signals from the two sensors by submersion into the molten metal. In that case, the two sensors are adjusted so that a weak signal is accepted from the slug and a strong signal is accepted from the molten metal of the body.

Although the present invention has been described with respect to a sampling device in which the level of the molten metal is used to determine the depth to which the sampler is submerged into the molten metal, the signal for the level of the molten metal is , or the signal for the slag level may be used for other control purposes, e.g.
It is clear that it can also be used to determine the position of the molten metal above the oxygen gas lance.

[Brief explanation of drawings]

FIG. 1 is a partially sectional view of the end of a lance of the invention carrying a specimen retrieval device or other device, and FIG. It is a connection diagram of an electric circuit. 1: Sensor, 3: Shutter contact, 4: Start push button, 5: Relay, 6: Relay, 7: Relay, 8:
Timer, 11: Limit switch, 12: Emergency retraction contact, 121: Bow contact, 20: Lance tube, 2
1: Rod, 22: Screw, 23: Rivet, 24: Lance tube hole, 25: Conductor, 26: Specimen extractor, 2
7: Sheath, 71, 72, 73, 74, 75: Relay contacts, 78: Timer, 81, 82: Contacts.

Claims (1)

[Scope of Claims] 1. A sample collection lance inserted into molten metal in a ladle or the like, which has a sample at its lower end in order to collect a sample at a certain depth in the molten metal. In a sampling lance having an ejector 26, the depth of the sampling lance in the molten metal is determined by: A non-contact type sensor 1 is installed at a predetermined distance above, a conductor 25 is provided that is connected to the sensor 1 and extends through the lance tube 20, and a conductor 25 is provided to the sensor 1. An external device is provided which is connected in a manner known per se and which processes the signal from the sensor 1 inputted through the conductor 25, so that the molten metal passes through the lower part of the lance tube 20, A hole 24 is provided in the wall of the lance tube 20 facing the sensor 1, and a sheath 27 made of a heat-resistant and electrically non-conductive material is closed so as not to flow into the interior of the tube 20. , provided around the lance tube 20,
A sampling lance, characterized in that the sheath 27 completely covers the hole 24 so that the sensor 1 does not come into contact with the molten metal. 2. The specimen collecting lance according to claim 1, wherein the hole has a sufficient width so that the sensor is not affected by the metal constituting the lance tube. . 3. The specimen collection lance according to claim 1, wherein the sensor is a non-contact induction sensor. 4. The specimen collection lance according to claim 1, wherein the sheath 27 is made of paper material.