JP2849528B2 - Hot dip galvanizing equipment for steel strip - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a continuous galvanizing equipment for steel strip.

[0002]

2. Description of the Related Art For example, Japanese Patent Application No. 3-127534 discloses a magnetic levitation device that changes the traveling direction while floating a steel strip in a non-contact manner by using the magnetic force of an electromagnet. It is intended to realize non-contact levitation using only force.

That is, as shown in FIG. 3, 11a to 11c are electromagnets, 12a to 12c are sensors for detecting the position of a steel strip,
3 is an auxiliary roll. The hot-plated steel strip 1 is turned in the non-contact direction and transported to the next step. On the other hand, an air cushion bearing (hereinafter, referred to as ACB) shown in FIG. 4 is used for turning the steel strip in a non-contact direction. That is, AC
B20 blows air out of the slit 21 and floats and transports the steel strip 1 by static pressure generated inside the rectangular slit path.

[0004]

In a magnetic levitation apparatus for a steel strip, when the steel sheet is thin, the power for generating a suction force for magnetically saturating the steel sheet and bringing the steel sheet into non-contact floating increases sharply. Therefore, in order to perform non-contact levitation using only electromagnetic force, it is necessary to take measures such as reducing the tension or increasing the bending radius of the steel strip. If the tension is lowered, it is necessary to take measures to suppress the walk of the steel strip, and if the bending radius of the steel strip is increased, the installation space of the equipment will be increased, etc. Requires a large control voltage, and if this is realized by a chopper power supply, an expensive large-capacity power supply is required. An object of the present invention is to provide a hot-dip galvanizing equipment for a steel strip which reduces power supply cost and equipment cost in non-contact levitation transfer of the steel strip.

[0005]

The gist of the present invention is as follows. (1) A plurality of electromagnets are arranged in a steel strip conveying passage of a hot-dip galvanizing line such that a suction surface for the steel strip is an arc, and a sensor and an electromagnet for measuring a distance between the suction surface of the electromagnet and the steel strip surface are provided. In hot-dip galvanizing equipment that provides a sensor that measures the flowing current, controls the excitation voltage of the electromagnet based on the position and current of the sensor, and turns the steel strip in a non-contact manner, a pulse power supply and a chopper power supply are allocated to each electromagnet. A hot-dip galvanizing equipment for steel strip, wherein a control system having a gap sensor and a current sensor is connected to each power supply. (2) The steel strip according to (1), wherein an air cushion bearing for generating a static pressure is disposed inside the slit path by blowing compressed air from a slit into a steel strip transport passage of the hot-dip galvanizing line. Hot dip galvanizing equipment.

[0006]

According to the present invention, a magnetic levitation device using an electromagnet and an ACB are arranged above a plating pot of a hot-dip galvanizing line to cause the steel strip to float at a certain position and change its traveling direction. No measures such as lowering and increasing the bending radius are required. In addition, since a pulse power supply and a chopper power supply are used together as a power supply for driving the electromagnet,
Equipment costs of a power supply for obtaining a control voltage for disturbance compensation can be reduced.

[0007] The present inventors have studied the required power when the ACB is used in combination with the magnetic levitation device and a 5 V limiter is imposed on the input voltage source by the following simulation. (1) magnetic levitation device electromagnet total 31 line height 10 m (2) Simulation parameters unit tension 1kg weight / mm ² thickness 2mm plate width 1m attraction 0.13 kg / cm ² (3) study results above specifications If the load supported by one electromagnet is calculated based on the above, it corresponds to supporting a load of 200 kg weight per electromagnet.

The total levitation force generated by one electromagnet and the ACB is set to be 200 kg, and when the levitation attraction generated by the electromagnet is changed, the steady power and the step-like disturbance required by the electromagnet are changed. The maximum power required to compensate for the above was obtained by simulation, and the relationship with the load supported by one electromagnet was obtained.

According to FIG. 2, when a levitation force of 200 kg weight is generated from an electromagnet without using an ACB, the steady power is 46 kW / piece and the maximum power is 10 ¹¹ kVA / piece per electromagnet. On the other hand, when the load generated from one electromagnet is 30 kg weight and the load generated from ACB is 170 kg weight, the steady power is 0.23 kW / piece, and the maximum power is 7.5 ×
10 ² kVA / piece.

Therefore, when converted into 31 electromagnets, A
When the CB is not used, a steady power of 1426 kW and a maximum power of 3.1 × 10 ¹² kVA are required. When the ACB and the magnetic levitation device are used together, a steady power of 7.13 kW and a maximum power of 2.3 × 10 ⁴ kVA are required. Required. When the ACB and the magnetic levitation device are used together, a constant power of 500 kW for driving the ACB is required. Even in consideration of this, the non-contact levitation can be performed with less power by using the ACB and the magnetic levitation device together. realizable.

Even when the ACB and the magnetic levitation device are used together, the maximum power required for disturbance compensation is 7.
It is 5 × 10 ² kVA / unit, and if this is realized by a normal chopper power supply, the power supply cost becomes high. By generating the necessary power temporarily with a pulse power supply for disturbance compensation,
Power costs can be reduced.

[0012]

An embodiment of the present invention will be described with reference to FIG. The steel strip 1 is plated in a plating pot 2, passed through a wiping device 4, and introduced into an alloying furnace and a cooler 3. Next, the steel strip 1 that has been alloyed passes through a steel strip transport passage in which the magnetic levitation device 11 and the ACB 6 are arranged. Magnetic levitation device 1
The first electromagnets 5a to 5n include a chopper power supply 7 and a pulse power supply 8
Are provided, and the power supplies 7 and 8 are electrically connected to a control system 10 provided with a current sensor 9 and a gap sensor 11.

That is, in the present invention, air is ejected from the ACB and acts as a levitation force on the steel strip. On the other hand, an attractive force is generated from the electromagnet, and a magnetic levitation force acts. The driving power of the electromagnet is determined from the gap value and the current value obtained from the gap sensor and the current sensor, and a chopper power source is normally used as a power source for driving the electromagnet. On the other hand, when large control power is temporarily required for disturbance compensation, a pulse power supply is also used. Therefore, in the present invention, the steel strip is carried by a hybrid structure of magnetic levitation and air levitation.

[0014]

According to the present invention, it is easy to compensate temporarily large control power for fluctuation of the tension of the steel strip during non-contact levitation transfer by using a pulse power supply together.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of the present invention.

FIG. 2 is a table showing a load supported by one electromagnet of the present invention and a maximum power / steady power.

FIG. 3 is an explanatory diagram of a magnetic levitation device.

FIG. 4A is an explanatory view of an air cushion bearing,
(B) is a development view of (a).

Continued on the front page (72) Inventor Keisuke Fujisaki 20-1 Shintomi, Futtsu Nippon Steel Corporation Technology Development Division (56) References JP-A-5-59511 (JP, A) JP-A-3-28356 ( JP, A) JP-A-2-277755 (JP, A) JP-A-63-12556 (JP, A) JP-A-2-62355 (JP, A) JP-A-52-84919 (JP, U) (58) ) Surveyed field (Int.Cl. ⁶ , DB name) C23C 2/00-2/40

Claims (2)

(57) [Claims] 1. A sensor for arranging a plurality of electromagnets in a steel strip conveying passage of a hot-dip galvanizing line such that a suction surface for the steel strip is formed in an arc, and measuring a distance between the suction surface of the electromagnet and the steel strip surface. A pulse power supply and a chopper power supply are provided for each electromagnet in a hot-dip galvanizing facility that provides a sensor that measures the current flowing through the electromagnet, controls the excitation voltage of the electromagnet based on the position and current of the sensor, and turns the steel strip in a non-contact manner. And a control system having a gap sensor and a current sensor connected to each power supply. 2. The steel according to claim 1, wherein an air cushion bearing for generating a static pressure is disposed inside the slit passage by blowing compressed air from a slit into a steel strip conveying passage of the hot-dip galvanizing line. Hot dip galvanizing equipment.