JPS6233000Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a billet heater that includes a hollow cylindrical heating coil and heats a billet conveyed inside the coil by electromagnetic induction.

In this type of billet heater, a billet such as a forging material is continuously conveyed inside a heating coil and heated to a predetermined temperature. In the billet heater 1 shown in FIG. 1, the billet 5 is heated while being conveyed on the skid rail 4 in the heating coil 2 at an appropriate speed, and then transferred to the skid rail 4 through a heat insulating box 7 located close to the outlet of the heating coil 2. The upper part is allowed to fall naturally and sent out to the outside, and is supplied to, for example, a forging machine (not shown). In this case, it is necessary that the billets 5 leaving the heating coil be fed one by one to the forging machine. However, when the surface temperature of the billets that are continuously conveyed through the heating coil is different from about 1260° to 1300°C, the ends of the billets often become welded to each other, which prevents normal feeding to the forging machine. . Several means are known for preventing this welding of billets together or for separating billets from each other if welding occurs. For example, the specification of Japanese Utility Model Publication No. 52-46883 proposes a means of applying vibration to skid rails during heating of billets to prevent billets from welding together. However, this method has the following drawbacks. In other words, billets that are heated while being continuously conveyed on skid rails actually weld to each other in a portion of the heating coil near the outlet; This makes billet conveyance unstable, and if the heating coil is long, its strength is affected by vibration, and there is a risk of leakage of cooling water from the heating coil and skid rail. In addition, the vibration of the skid rail may cause cracking or peeling of the refractory lining provided on the inner surface to protect the insulation of the heating coil.

In addition, the specification of Utility Model Publication No. 53-10405 states that on the exit side of the billet of the heating coil, a presser roller is provided on the front side in the direction of billet movement, and an eccentric roller is provided on the rear side a predetermined distance from the presser roller for welding. Means have been proposed to separate the billets that have caused this. However, in this method, since the roller device is provided outside the heating coil, it takes time for the billet to be separated after leaving the heating coil, and there is a drawback that the temperature of the billet decreases during that time.

In view of the drawbacks of the above-mentioned known means, the present invention
A simple and economical means of reliably separating welded bits from each other without adversely affecting the heating coil itself or the refractory lining that protects its insulation, and without causing a drop in the temperature of the billet. The purpose of the present invention is to provide a billet heater equipped with the following.

According to the present invention, in the above-mentioned billet heater, when the billet sent to the outside from the heating coil advances in a heat-retaining box disposed immediately in front of the heating coil when viewed in the direction in which the billet travels, This is accomplished by providing a device that detects the front end of the billet at the same time, holds the front end of the billet perpendicular to the direction of movement of the billet, and separates the welded billet from the following billet.

Next, the present invention will be explained in detail based on the embodiments shown in the drawings.

In FIG. 2, the heating coil 2 impregnated with heat-resistant varnish is held by appropriate means in a coil box 6 made of a non-metallic material after being taped to a predetermined value with glass mica tape and glass tape. The inside of the heating coil 2 is covered with a lining 3 made of monolithic refractory material, and is protected from the heat of the billet 5 conveyed in the direction of the arrow on skid rails 4 arranged along the inside of the lining 3. A heat-retaining box 7 is provided immediately in front of the heating coil 2 when viewed in the direction in which the billet travels, and the billet 5 sent out from the heating coil 2 is heat-retained and uniformized within the heat-retaining box. At that time, the surface temperature inside the heating coil 2 near the outlet is 1260℃ or more.
As described above, since the billets 5 that have reached 1300°C are welded together and reach the heat insulating box 7, it is necessary to separate them individually and supply them to the outside. In FIG. 2, two rods made of heat-resistant material of different lengths are arranged so as to straddle the insulation box 7 immediately in front of the heating coil 2 when viewed in the direction of billet movement. Billet holding rods 9 and 10 are arranged, and holding arm 1
2 and a bearing 11 whose position is fixed, the billet is supported perpendicularly to the direction of movement of the billet. Furthermore, the billet push rod 9 is moved by a lifting device 8 which is fixed to a bearing 11 and whose movable part is connected to a holding arm 12.
and 10 can move up and down using the bearing 11 as a guide.

When the now welded billet 5 protrudes from the outlet of the heating coil 2 and advances inside the heat insulation box 7, a non-contact detection device, for example, a photoelectric switch 13 placed near the exit of the heat insulation box 7 detects the front end of the billet 5 from the side. is detected and a signal is sent to the billet push rod lifting device 8 via an electrical circuit (not shown) normally used in devices of this type. Upon receiving the signal, the billet push rod lifting device 8 drives its movable portion to lower the two billet push rods 9 and 10 of different lengths together with the holding arm 12. The two lowered billet holding rods 9 hold down the front end of the billet detected by the photoelectric switch 13 and separate the billet 5 from the following billets that are welded together. The separated billet 5 falls naturally along the skid rail and is carried outside.
At this time, the shorter billet holding rod 10 located at the rear as seen in the direction of billet movement holds down the rear end of the separated billet 5 or the front end of the following billet, and prevents the reaction generated when the billet 5 is separated. This suppresses the movement and prevents damage to the lining near the outlet of the heating coil 2 and the inner lining of the heat insulation box 7 caused by collision of billets.

In this case, each time the charging switch 13 detects the front end of the welded billet subsequently advancing into the warming box 7 after the previous billet has been separated, the lifting device 8 repeats its vertical movement, In each case, the welded billet is separated safely and reliably from the following billet, and since the separation of the billets is always carried out in the heating box 7, the heating coil 2
There is no drop in the temperature of the billet between leaving it and being separated.

As explained above, the present invention is a billet heater that is equipped with a hollow cylindrical heating coil and heats a billet conveyed inside the heating coil by electromagnetic induction, in which the billet sent out from the heating coil is heated in the direction of movement of the billet. The front end of the billet is detected as it moves through a heat insulating box located immediately in front of the heating coil, and the front end of the billet is held down perpendicular to the direction of movement of the billet and the billet is welded to the billet. By providing a device for separating billets from the succeeding billet, it is possible to easily and reliably separate billets that have been welded together without damaging or otherwise adversely affecting the heating coil, its protective lining, and the inner lining of the insulation box. .

[Brief explanation of the drawing]

Fig. 1 is a schematic longitudinal sectional view showing the vicinity of the billet outlet of a conventional billet heater equipped with a heat insulating box, and Fig. 2 is a schematic longitudinal sectional view showing the vicinity of the billet outlet of the billet heater of the present invention equipped with a heat insulating box and a billet separating device. Each represents a longitudinal cross-sectional view. 1... Billet heater, 2... Heating coil, 5
... Billet, 7... Warm box, 8... Lifting device, 9, 10... Billet holding rod, 13... Billet front end detection device.

Claims (1)

[Claims for Utility Model Registration] 1. A billet heater that is equipped with a hollow cylindrical heating coil and heats a billet conveyed inside the heating coil by electromagnetic induction, in which the billet sent out from the heating coil is heated to the outside of the billet. The front end of the billet is detected as it moves through a heat insulating box placed immediately in front of the heating coil when viewed in the direction of travel, and the front end of the billet is held down perpendicular to the billet travel direction and welded to each other. A billet heater comprising a device for separating a billet from a subsequent billet. 2. Utility Model Registration Scope of Claims 1. The billet heater according to claim 1, wherein the billet separating device is arranged in front and behind in the billet traveling direction, and is moved up and down perpendicularly to the billet traveling direction by an attached lifting device. Consisting of two rods of different lengths, when the longer rod located at the front as seen in the direction of movement of the billet holds down the billet and separates it from the following billet, the shorter rod located at the rear A billet heater characterized in that the rear end of the billet or the front end of a succeeding billet is suppressed in order to suppress the dynamic movement that occurs as a reaction to separation of the billet. 3 Scope of claims for utility model registration, paragraph 1 or 2
3. The billet heater according to item 1, further comprising a non-contact detection device for detecting the front end of the billet.