JPS6016494B2 - Tube heat treatment furnace - Google Patents

Description

[Detailed description of the invention] The present invention relates to a heat treatment furnace for pipe bodies such as cast iron pipes.

As a heat treatment for cast iron pipes, there is a method in which a desired ferrite structure is obtained by raising the pipe body to a certain temperature and then cooling it at a predetermined cooling rate. For this heat treatment, conventionally, continuous furnaces have been frequently used to heat and slowly cool the tube while transporting it, but this requires a considerably long distance and a large space to slowly cool the tube. Also, because the space was large, heat loss was also large. On the other hand, batch type furnaces have also been used, but they have been inefficient. SUMMARY OF THE INVENTION An object of the present invention is to provide a heat treatment furnace that solves the above problems, allows efficient processing in a small space, and prevents tubes from becoming oval due to high temperatures during heat treatment. In order to achieve the above object, the present invention provides a furnace chamber capable of accommodating a plurality of tubes in parallel at appropriate intervals, and rotates the tubes in a direction perpendicular to the axis of the tubes to transport the tubes. A chain conveyor in which a pipe body is supported by a sandalwood surface is installed, and engaging parts that engage the pipe body are attached at appropriate intervals, and the conveyor rotates intermittently from the inlet to the outlet. A rotary chain is arranged in parallel with the chain conveyor. With such a system, heating and slow cooling can be carried out while transferring the tube body intermittently, so the furnace body is small and inexpensive, and the installation space is small, and it is equipped with a chain conveyor and multiple engaging parts. In combination with a rotary chain, the tube can be transported and rotated at the stop position with a simple configuration, and it is possible to prevent the tube from becoming oval during heat treatment.

Hereinafter, one embodiment of the present invention will be described based on the drawings.

Reference numeral 1 denotes a furnace body, which constitutes a furnace chamber A that can accommodate a plurality of tubes P (five in the figure) in parallel at appropriate intervals. An inlet 2 and an output 3 are formed at the end of the pond.

A loading chamber 4 for the tube body P is provided adjacent to the furnace chamber entrance 2;
The red-hot tube P that has just been pulled out of the rotary mold of the centrifugal casting machine is brought into the furnace chamber A while suppressing its temperature drop.
It is designed so that it can wait until it is brought inside. A lift door 6 is provided between the furnace chamber entrance 2 and the loading chamber 4, and a furnace chamber exit 3 is provided.
An elevating door 6 is provided. Furthermore, an intermediate lifting door 7 is provided at an intermediate position in the parallel direction of the tubes in the furnace chamber A, and the intermediate lifting door 7 allows the furnace chamber A to be divided into a heating chamber AI on the furnace chamber entrance side and a scraping chamber A2 on the furnace chamber exit side. It is divided into. A burner 8a is located on the upper wall of the furnace body 1 in the heating chamber AI section above the tube body P arrangement position.
, 8b are arranged, and the top of the tube P is directly heated with high temperature gas to raise the temperature of the tube to a predetermined temperature. Further, a cooling pipe 9 is disposed at the upper part of the heating chamber AI side of the slow cooling chamber A2, so that the pipe body P can be efficiently slow cooled within a predetermined cooling rate range. A damper 1 is connected to the cooling pipe from a blower 10 installed on the furnace body 1.
1. Cooling air is sent through the distribution header 12, and heated air that has passed through the cooling pipe 9 is sent through the collecting header 13 and the air pipe 14 to the burners 8a and 8b as combustion air. A chain conveyor 15 is disposed in the lower part of the furnace chamber A. The chain conveyor 15 rotates to transport the tube P from the furnace chamber inlet 2 to the furnace chamber outlet 3 and to rotate the tube P. 16
1 is an endless chain of the chain conveyor 15 whose outer circumferential surface serves as a direct conveyance surface for the tube bodies P, and a plurality of endless chains are arranged in parallel at appropriate intervals in the tube axis direction.

17 is a driving sprocket disposed on the furnace chamber outlet 3 side;
8 is a driven sprocket arranged on the furnace chamber entrance 2 side.

Reference numeral 20 denotes a rotary chain disposed in parallel with the chain conveyor 15, and the rotary chain 20' has a protrusion 21 that engages with the pipe P from the front side in the transport direction. Installed at intervals.

This rotary chain 2 is wound between a driving sprocket 22 disposed near the furnace chamber entrance 2 and a driven sprocket 23 disposed near the furnace chamber outlet 3. It is configured to rotate intermittently in the pipe body P transfer direction by a mounting pitch of 21. Reference numeral 24 denotes a tube delivery device disposed at the lower part of the loading chamber 4, which is equipped with a head movement frame 25, in which the tube P pulled out from the rotary frame is brought onto the rotation frame 25, It is configured so that the tube body P can be delivered into the furnace chamber A by moving the frame.

26 is a rolling wheel disposed so as to be connected to the furnace chamber outlet 3.

Although FIG. 1 shows a rotary chain with two protrusions 21, the main point is to stop the transfer of the tube P that engages with the tube P from the front in the direction of conveyance, and to rotate the chain conveyor 15. It is also possible to use an engaging portion that rotates the tubular body P on its own axis as the tubular body P rotates. Therefore, as shown in FIG.

Next, to explain the operation, in order to heat-treat the tube body P, the chain conveyor 15 is constantly driven in the direction of the arrow, and the protrusion 2
Alternatively, the rotary chain 20 is stopped with the engaging part consisting of the roller 27 positioned at a predetermined position, and the elevating door 5 is raised to send out the pipe P that has been carried into the loading chamber 4. It is carried into the furnace chamber entrance 2 by the device 24. The elevator door 5 closes immediately after loading. The pipe body P carried in is transferred by the chain conveyor 15 and is engaged with the protrusion 21 or roller 27 located at the first stop position to stop the transfer. In this state, the pipe body P is moved by the rotation of the chain 16. Along with it, it rotates like an arrow. At this first stop position, the tube P is connected to the upper burner 8a.
The top is directly heated to a predetermined temperature. Although the temperature of the tubular body P rises due to this heating and it becomes easily deformed, since the tubular body P is rotated as described above, the tubular body P is prevented from becoming oval. After a certain period of time has passed, the spreading chain 20 moves to the protrusion 21.
Or the roller 27 is rotated by one pitch, and the protrusion 2
1 or roller 27 stops at the second stop position. Tube P
is transferred by the chain conveyor 15, engages with the protrusion or roller 27 at this second stop position, and is heated by the burner 8b while rotating in the same manner as described above, and is maintained at a predetermined temperature for a predetermined time. Thereafter, by raising the intermediate lift door and rotating the rotary chain 20 by one pitch again, the pipe body P leaves the heating chamber AI and reaches the winding room A2, and slowly rotates at the third stop position. It is cooled down. Thereafter, the tubular body P is slowly cooled while rotating in the same manner at the fourth and fifth stopping positions, and is then carried out to the transfer body 26 from the furnace chamber outlet 3 where the heat treatment has been completed. In addition, in the above description, only one tube P was explained one by one in order to simplify the explanation, but it goes without saying that in reality, a plurality of tubes are continuously heat-treated at the same time. In the above embodiment, the chain conveyor 15 rotates from the furnace chamber inlet 2 toward the outlet 3, and the protrusion 21 or roller 27 of the rotary chain 20 engages with the tube P from the side in the transfer direction. However, the chain conveyor 15 is rotated from the furnace chamber entrance 3 toward the entrance 2, and the rotating chain 20
It is also possible to engage the protrusion 21 or roller 27 with the tube P from the rear side in the transfer direction so that the tube P can be transferred by two rotating chains.

In this case, the length of the spreading chain 20 needs to be the same as or longer than the chain conveyor 15. Also,
In the above embodiment, the furnace chamber A is divided into a heating chamber AI and an annealing chamber A2, and each has two and three stopping positions, but depending on the composition of the tube body, casting conditions, etc. There is no need to divide the area into two, and the number of stopping positions can be changed arbitrarily.

Note that by partitioning the furnace chamber A by providing the intermediate elevator door 7 or a curtain, the necessary temperature gradient can be obtained even if the furnace chamber A is shortened. According to the tube heat treatment furnace of the present invention, as is clear from the above description, since heating and slow cooling can be performed while transferring the tube intermittently, the furnace body is small and inexpensive, and the installation space is small. In addition, by combining a chain conveyor and a rotating chain with multiple engaging parts, the tube can be transferred and rotated at the stop position with a simple configuration, preventing the tube from becoming oval during heat treatment. can.

BRIEF DESCRIPTION OF THE DRAWINGS The drawings show an embodiment of the present invention, with FIG. 1 being a longitudinal sectional front view of the entire device, and FIG. 2 being a front view showing a modification of the engaging portion of the rotating chain. 1...Furnace body, 2...Furnace chamber inlet, 3...Furnace chamber outlet,
4... Loading room, 5, 6... Elevating door, 7... Intermediate elevating door, 8a, 8b... Burner, 9... Cooling pipe,
15...Chain conveyor, 16...Endless chain, 2
0...Rotating chain, 21...Protrusion 4 engaging part), 27
...roller (engaging part), A...furnace chamber, AI...heating chamber, A
2...Annealing chamber, P...Pipe body. Figure 1 Figure 2

Claims (1)

[Claims] 1. A furnace chamber capable of accommodating a plurality of tube bodies in parallel at appropriate intervals is provided, and the tube bodies are mounted and supported on the conveying surface of the furnace chamber, which rotates in a direction perpendicular to the axis of the tube bodies. A chain conveyor is disposed, and a rotary chain for intermittent transfer is arranged in parallel to the chain conveyor, and engaging parts that engage with the pipe body are attached at appropriate intervals, and the intermittent transfer rotation chain rotates intermittently from the inlet to the outlet. A tube heat treatment furnace characterized by: