JPS6017807B2 - Wire heating furnace - Google Patents

Description

[Detailed description of the invention] The present invention relates to a heating furnace for wire rods such as iron wire and steel wire.

To heat this seed wire, it is necessary to maintain the wire at a temperature of 800 to 1050° C. for 40 to 60 seconds.

Wire heating furnaces are used to heat wire rods to such high temperatures, and conventionally, they have generally been fueled with heavy oil or gas. By the way, this kind of heating furnace can be roughly divided into two types depending on the method of heating the wire: direct-fire method, which burns heavy oil or gas and directly heats the wire with the heat, and direct-fire method, which burns heavy oil or gas and uses the heat to directly heat the wire. It is classified as an indirect heating method in which the wire is heated by the radiant heat from the pipe, but the former method has good thermal efficiency but has the disadvantage that oxidation scale is generated and the wire becomes thin. Although the latter method does not have such drawbacks, it has the drawbacks of large heat loss, high fuel consumption, and high maintenance costs. That is, each of these methods has advantages and disadvantages, and the current situation is that no satisfactory heating furnace exists. Therefore, the main object of the present invention is to provide an extremely useful wire heating furnace that preserves the advantages of the direct heating method and the indirect heating method and eliminates the drawbacks.

In order to achieve this object, the present invention eliminates the heating furnace structure in which fuels such as heavy oil and gas are burned, and uses a longest metal tube as the furnace body of the heating furnace, and generates heat by passing an electric current through the tube. A configuration is adopted in which the wire is directly heated with heat. Safety is ensured by devising the type and magnitude of the current that passes through the long tube, and the position of the electrodes provided on the long tube for passing this current through the long tube. Next, one embodiment of the present invention will be described based on the drawings.

Figure 1 shows the iron wire from the stock part 1 wound into a roll.
The wire heating furnace 7 of the present invention is applied to equipment in which a wire 2 such as a steel wire is fed out through a pinch roller 3 and a guide die 4, and is supplied to a plating tank 6 while being guided by a rear guide roller 5. Here is an example. The heating furnace 7 includes a longest metal tube 8 provided in front of the plating tank 6 with the wire 2 inserted through it, and negative electrodes 9 and 9 provided at both ends 8a and 8b of the long tube 8. , a positive electrode 10 provided at a suitable position on the longest tube 8 between both negative electrodes 9, 9, and this positive electrode 10.
and a low voltage/high current DC power source 11 connected to both negative electrodes 9,9. The long tube 8 is, for example, a super heat-resistant steel tube with a length of 5 to 25, an inner diameter of 10 ribs, and an outer wall 16 side. In actual use, in order to heat a plurality of wire rods in parallel, a configuration is used in which a plurality of the long tubes 8 are inserted in parallel into the outer case 12 as shown in FIG. 2.
Then, the outer box 12 is filled with a heat insulating material 13 such as ceramic fiber to keep the long tubes 8 warm (
(See Figure 3). Further, a temperature sensing element 14 such as a thermistor is provided on the surface of each long tube 8 to detect the tube temperature. Each of the electrodes 9, 9 and 1 is made of a material that does not melt due to the heat generation temperature of the long tube 8, and is provided on the long tube with a tight fit so as not to cause poor contact due to the heat generation temperature. There is.

Note that the positive electrode 10 is provided at both negative electrodes 9, 9.
It is preferable that the long tube be approximately in the center in the longitudinal direction so that the same current flows toward the long tube 8 and the long tube 8 generates heat uniformly. The DC power supply 1
1 consists of a transformer 15 that converts an AC voltage of, for example, 220y to a low voltage such as IV or 3V, and a rectifier circuit 16 that rectifies the secondary output of the transformer 15, and the positive terminal 16a of the rectifier circuit is connected to the By connecting the positive electrode 10 and the negative terminal 16b to the member electrodes 9, 9, the low voltage and high current generated in the rectifier circuit 16, such as 1 volt and 10,000 amperes or 3 volts and 5,000 amperes of DC power. is configured to be supplied to the long tube 8.

Further, a thyristor 17 is inserted into the primary side of the transformer 15, and changes the conduction angle according to the temperature detected by the temperature sensing element 14 to adjust the combined power to the long pipe 8. The emitted heat temperature of the long tube 8 is controlled. According to this configuration, the longest tube 8 has an electric resistance and a DC power source 11
Generates Joule heat by high current supplied from
The tube temperature is increased to a temperature required to heat the wire 2.

Once the temperature reaches the required temperature, the temperature is maintained by the action of the temperature sensing element 14 and the thyristor 17. Therefore, the wire strip 2 is transferred within the long tube 8 over a required period of time (40 to 6 pieces of sand) and is directly heated in the long tube 8 to a predetermined temperature. In this case, the positive electrode 10 and the negative electrodes 9, 9
Since the potential difference between them is a low voltage of 1 volt or 3 volts, there is no risk of electric shock even if a worker accidentally touches the long tube 8, and since the voltage is direct current, the negative electrode 9,
9 are provided at both ends 8a and 8b of the long tube, so that current leakage and voltage induction to the wire 2 can be prevented by grounding the negative electrodes 9 and 9 to the Naoto earth, or by grounding the negative terminal 16b of the DC power supply 11. The plating action in the plating bath 6 is not affected.

That is, if we were to use an AC power source, an alternating current would flow through the finite long tube 8 to induce an electromotive force in the wire 2, and this induced electromotive force would adversely affect the plating process in the plating tank 6. However, by configuring as described above, these disadvantages will not occur.As explained above, this invention provides a long metal tube with a wire inserted through it, and Negative electrodes are provided at both ends of the long tube, and a positive electrode is provided on the long tube between both negative electrodes, and a DC power source is connected between these positive and negative electrodes to supply low voltage and high current DC power to the long tube. Because the structure is configured to generate heat in the long length tube by combining the two, and heat the wire inside it,
Gain the following benefits: ○) In principle, it is a direct fire method, but unlike the secondary method, gas or heavy oil is not used as a heating source, so there is no generation of oxidized scale and the thermal efficiency is high.

That is, the heating furnace of the present invention can be said to be a heating furnace that retains only the advantages of the conventional direct heating type heating furnace and indirect heating type heating furnace and eliminates all the disadvantages. {21 Since the long tube is heated with low-voltage DC power, there is no danger to the human body, and since negative electrodes are provided at both ends of the longest tube, there is no possibility of electrical leakage in the wire or induction of electromotive force. Therefore, interference with subsequent processes such as plating can be prevented.

'3} Compared to secondary methods that use heavy oil or gas as fuel, equipment and construction costs are lower, and less space is required.

There is also no need to worry about air pollution as there is no exhaust gas emitted.
Additional equipment for air purification is not required. [4- Because the heat conversion rate is good, even if electricity is used, the maintenance cost is lower than that of gas or heavy oil.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, in which FIG. 1 is an overall configuration diagram, FIG. 2 is a perspective view of a main part, and FIG. 3 is a longitudinal sectional view of a main part. 2... Wire rod, 7... Wire heating furnace, 8...
...Long tube, 8a, 8b...Both ends, 9...
...Negative electrode, 10...Positive electrode, 1 1...
・DC power supply. Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] 1. A long metal tube into which a wire is inserted, a negative electrode provided at both ends of the long tube, a positive electrode provided at an appropriate position on the long tube between both negative electrodes, and this positive electrode. and a low-voltage, high-current DC power source connected to both negative electrodes, and the long tube is configured to generate heat using the DC power supplied from the DC power source to heat the wire therein. A wire heating furnace characterized by: