JPH0548076Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to a tunnel-type heating furnace that heats a tube while feeding it in the axial direction of the tube.

This idea can be used to preheat pipes immediately before painting them.

[Prior Art] When painting a pipe, the pipe is sometimes preheated immediately before applying the paint. For example, when applying epoxy resin powder coating to the outer circumferential surface of a pipe, the pipe is preheated to 230°C immediately before painting. A tunnel-type heating furnace is used to preheat the tube. A tunnel-type heating furnace includes a furnace body through which a tube passes, a lid that has a through hole that fits into the outer peripheral surface of the tube and closes an opening at the entrance and exit of the furnace body, and a tube conveying device that conveys the tube in the tube axis direction. ing. Heating gas is used as the heating means. Since a tunnel-type heating furnace heats tubes of multiple diameters, the opening diameter of the furnace body entrance and exit is set to match the diameter of the tube with the largest diameter to be heated. A plurality of lids are prepared, and the diameters of the through holes in the lids are different from each other so as to correspond to tubes having different outer diameters. Additionally, the lid is made of ceramic fiber covered with an iron plate, making it able to withstand temperatures of 1,000 degrees Celsius. The tube conveying device rotates the tube around the tube axis and feeds the tube in the tube axis direction.

[Problems to be solved by the invention] In the tunnel-type heating furnace described above, the lid is replaced depending on the outer diameter of the tube to be heated. The weight of the lid is e.g.
At 150 kg, it is too large to be carried by human power. Therefore, conventionally, when the outer diameter of the tube was changed, the lid was removed from the furnace body using a crane and reattached to the furnace body. For this reason, it took a long time to replace the lid, and the replacement work was dangerous because it involved handling heavy objects.

Therefore, this invention aims to provide a tunnel-type heating furnace whose lid can be quickly and safely replaced without using transportation equipment such as a crane.

[Means for Solving the Problems] The tunnel-type heating furnace of the first invention is provided with a lid support device at each entrance and exit of the furnace body. Each lid support device extends in a direction perpendicular to the tube feeding direction;
It has a plurality of lid support members arranged in parallel. Each lid support member supports the lid movably along its longitudinal direction.

In the tunnel type heating furnace of the second invention, a lid support device is provided at each entrance and exit of the furnace body. Each lid support device extends in a direction perpendicular to the tube feeding direction;
It has a plurality of lid support members arranged in parallel. Also,
Each lid consists of a pair of divided bodies each having a semicircular notch corresponding to the outside diameter of the tube. Each lid support member supports the divided body movably along its longitudinal direction.

In the first and second inventions, the heating furnace may consist of a plurality of furnace bodies arranged along the tube feeding direction. In this case, the tube conveying devices may be provided between adjacent furnace bodies.

The number of lids prepared at each entrance and exit of the furnace body is
Depending on the diameter of the pipe to be heated, the number is, for example, 2 to 6.

A rail, a guide plate, etc. are used as the lid support member. The lid is supported by hanging from a rail, guide plate, etc., or by placing it on these members. To facilitate movement of the lid, it is desirable to suspend or rest the lid via rollers.

In order to move the lid or the lid divisions forward and backward with respect to the furnace body, a manual operation, an air cylinder, a hydraulic cylinder, or a combination of a motor and a pinion rack mechanism or a screw mechanism are used.

The order of arrangement of the lids along the tube feeding direction is to arrange the lids with larger through-hole diameters from the one closest to the furnace body. In addition, when multiple lids are overlapped along the tube feeding direction to close the opening of the furnace body entrance and exit, from the point of view of suppressing the leakage of heated gas from the gap of the through hole that is larger than the outside diameter of the tube,
It is desirable that the interval between adjacent lids in the tube feeding direction be as small as possible.

[Function] Select a lid with a through hole that fits on the outer circumferential surface of the tube, and closes the opening of the entrance and exit of the furnace body. When replacing the lid, the lid is moved along the lid support member and brought to the entrance/exit of the furnace body. Since the lid is supported by the lid support member, there is no need to move the lid up and down, and the force required to move the lid is small. In addition, when heating a small-diameter tube, this small-diameter tube lid and a lid having a through hole larger than this tube diameter may be overlapped to close the opening of the furnace body entrance and exit. In this case, leakage of heated gas can be prevented.

In addition, if the lid consists of a pair of divided bodies, move the divided bodies from both sides of the tube along the lid support member, and fit the semicircular notches on both sides of the tube. Sandwich the divided body.

[Example] FIG. 1 shows an example of a tunnel-type heating furnace of the first invention. The tunnel type heating furnace of this example has four diameters of 400 mm, 800 mm, 1200 mm and 1500 mm.
Heating types of tubes.

As shown in the drawing, the tunnel type heating furnace includes four furnace bodies 10 arranged along the feeding direction of the tube 1. Since the tubes 1 between adjacent furnace bodies 10 are exposed to the atmosphere and cooled, the interval between the furnace bodies 10 is made as narrow as possible. Each furnace body 10 has a through hole 11 through which the heating tube 1 passes. The through hole 11 of the furnace body 10 has a diameter corresponding to the maximum diameter tube 1. A heating gas supply pipe 13 and an exhaust pipe 14 are connected to each furnace body 10.

A lid support device 17 is provided adjacent to the entrance and exit of each furnace body 10, respectively. As shown in FIG. 2, the lid support device 17 includes a support frame 18, and three rails 2 are provided at the top of the support frame 18.
0 is attached so as to extend parallel to the direction perpendicular to the tube feeding direction.

As shown in FIG. 3, lids 23, 25, and 27 are suspended from each rail 20 of the lid support device 17 via rollers 30. As shown in FIG. Therefore, the furnace body 1
Three lids 23, 25, and 27 will be placed at each entrance and exit of 0. Each lid 23, 25, 27 has through holes 24, 26, 28 of different diameters corresponding to the tubes 1 having different outer diameters, and the lid with a larger through hole is arranged closer to the furnace body 10. ing. In this embodiment, the through holes 2 of the lids 23, 25, 27 are
The diameter of 4, 26, 28 is 850mm, 1250mm and
It is 1550mm. In addition, adjacent lids 23, 25, 2
The gap between 7 is 25mm. Through holes 24, 26,
The center of 28 coincides with the center of the tube 1 to be transported. Therefore, the lid that corresponds to the smaller diameter tube 1,
The through hole is in a low position.

At the entrance and exit of each furnace body 10, a pair of transport rolls 33 are arranged on both sides of the transport line. The transport roll 33 is rotationally driven by a motor 34. The conveyance rolls 33 are movable in a direction perpendicular to the furnace center line 15, and the interval between the conveyance rolls 33 is adjusted according to the outer diameter of the tube 1 to be conveyed. Further, since the transport roll axis is slightly inclined with respect to the furnace center line 15, the tube 1 is fed in the tube axis direction while rotating around the tube axis.

Note that an epoxy resin powder coating coating device (not shown) is disposed on the outlet side of the tunnel-type heating furnace.

Here, a method for heating the tube 1 using the tunnel heating furnace configured as described above will be described.

First, the through holes 24, 26, which fit into the outer peripheral surface of the pipe,
Select the lids 23, 25, and 27 with 28 to close the opening of the entrance and exit of the furnace body. The lids 23, 25, 27 are moved along the rail 20 by hand. Figure 1 shows the case of heating a tube 1 with the smallest diameter (400 mm).
Three lids 23, 25, and 27 close the opening of the furnace body entrance and exit. Further, FIG. 2 shows a case where a pipe 1 of medium diameter (1200 mm) is heated, and the entrance and exit of the furnace body 10 is closed with one lid 23. other two lids 2
5 and 27 are held by a lid support device 17 at positions away from the furnace centerline 15.

Further, the interval between the conveyor rolls 3 is adjusted according to the pipe diameter. That is, the spacing between the rolls is widened for a tube 1 with a large outer diameter, and narrowed for a tube 1 with a small outer diameter.

When the lids 23, 25, and 27 are attached and the roll spacing is adjusted, the transport rolls 33 are driven to transport the tube 1 in the tube axis direction. Further, heating gas of 1000° C. is supplied into the furnace body from the heating gas supply pipe 13, and the tube 1 passing through the furnace body is heated to 230° C. by the heating gas. Incidentally, the tube 1 coming out of the tunnel heating furnace is immediately sprayed with an epoxy resin powder coating. The sprayed paint is fused to the tube surface by the heat of the tube 1, forming a paint film.

4 to 6 show an embodiment of the second invention. In these drawings, members similar to those in the first embodiment are given the same reference numerals, and explanations of these members will be omitted.

The lid 4 is attached to the three rails 20 of the lid support device 17.
1, 45, and 49 are suspended via rollers 30, respectively. The lids 41, 45, 49 each have a pair of divided bodies 4 divided into two in the radial direction.
It consists of 3, 47, 51. Lid 41, 44,
49 is divided into two in the radial direction, so the lid 4
The through holes 42, 46, 50 of No. 1, 45, 49 are also divided into two, and semicircular notches 44, 48, 52 are formed in each of the divided bodies 43, 47, 51. Further, air cylinders 54 are fixed to the pillars 21 on both sides of the lid support device 17, respectively.
The tip of the rod 55 of No. 4 is attached to each divided body 43, 47, 5.
It is connected to the side of 1. By driving the air cylinder 54, each divided body 43, 47, 51
moves along the rail 20.

FIG. 4 shows a case in which a tube with the smallest diameter is heated, and the divided bodies 43 and 47 of the lids 41 and 45 are retracted to a separate position on the side of the furnace body. In addition, Fig. 6 shows the case of heating a medium-diameter tube, and two lids 4 are used.
The divided bodies 43 and 51 of No. 1 and 49 are retracted to the side.

[Effects of the invention] According to this invention, the lid is moved along the lid support member and brought to the entrance and exit of the furnace body. Since the lid is supported by the lid support member, there is no need to move the lid up and down, and the force required to move the lid is small. Therefore, the lid can be replaced quickly and safely. For example, it used to take 80 minutes to replace a lid, but with this invention, the lid can be replaced in 20 minutes.

[Brief explanation of the drawing]

FIG. 1 shows an embodiment of the first idea.
FIG. 2 is a perspective view of a lid holding member provided in the heating furnace shown in FIG. 1, FIG. 3 is an enlarged sectional view of a portion of the lid holding member, and FIG. 5 shows a front view of the lid and lid holding member, FIG. 5 is a side view of the lid and lid holding member shown in FIG. 4, and FIG. 6 shows an embodiment of the second invention. It is a front view which shows the state of a lid in the case of heating. 1...Pipe, 10...Furnace body, 11...Through hole, 1
7...Lid support device, 20...Rail, 23,2
5, 27, 41, 45, 49... Lid, 24, 2
6, 28, 42, 46, 50...through hole, 30...
... Roller, 33 ... Conveyance roll, 43, 47,
51...Divided body, 44, 48, 52...Semicircular notch, 54...Air cylinder.

Claims (1)

[Scope of Claim for Utility Model Registration] 1. A furnace body through which a tube passes, a lid having a through hole that fits into the outer peripheral surface of the tube and closing the opening of the entrance and exit of the furnace body;
In a heating furnace equipped with a tube conveying device for transporting tubes in the tube axial direction, and a plurality of replaceable lids having through holes of different diameters corresponding to tubes with different outer diameters, Each of the lid support devices is provided with a lid support device, and each lid support device extends in a direction perpendicular to the tube feeding direction and has a plurality of lid support members arranged in parallel. A tunnel type heating furnace characterized in that the lid is movably supported. 2. A furnace body through which the tube passes, and a lid that has a through hole that fits into the outer peripheral surface of the tube and closes the opening of the entrance and exit of the furnace body;
In a heating furnace equipped with a tube conveying device for transporting tubes in the tube axial direction, and a plurality of replaceable lids having through holes of different diameters corresponding to tubes with different outer diameters, Each lid support device is provided with a lid support device, and each lid support device has a plurality of lid support members that extend in a direction perpendicular to the tube feeding direction and are arranged in parallel, and each of the lids has a semicircular shape corresponding to the outside diameter of the tube. What is claimed is: 1. A tunnel-type heating furnace comprising a pair of divided bodies each having a shaped notch, each lid support member movably supporting said divided body along its longitudinal direction.