Oil quenching system

Abstract

To provide an oil quenching system that suppresses the spread of flames when the heat-treated material is immersed in an oil tank during the process of moving the heat-treated material, which has been removed from a vertical furnace, into the oil tank for oil quenching. [Solution] The device includes a moving mechanism that engages with the lid of a vertical furnace suspended from the lower part of a rod-shaped steel material so as to extend vertically, lifts the material to be heat-treated from inside the vertical furnace, moves it to directly above the upper opening of the oil tank, and lowers it so as to immerse it in the oil tank, and includes a hood member that is positioned at the upper opening of the oil tank and has an annular portion that extends upward so as to extend the wall of the oil tank and has a cross-sectional shape that allows the lid to be fitted inside, and the lid is fitted into the annular portion of the hood member and lowered.

Description

Technical Field

[0001] The present invention relates to an oil quenching system for performing oil quenching by moving a heat-treated material taken out from a vertical furnace to an oil tank.

Background Art

[0002] For long and large bar-shaped metal materials (heat-treated materials) used for shafts of aircraft engines, etc., heat treatments such as quenching and tempering are performed using a vertical furnace.

[0003] For example, in Patent Document 1, a vertical furnace is disclosed in which a furnace body having a peripheral wall and a bottom wall and an opening at the upper end has a furnace lid disposed at the opening, and a bar (shaft)-shaped heat-treated material is accommodated in a suspended state inside the furnace body for heat treatment. Here, two heat-treated materials are suspended from the furnace lid and heated at a temperature of 900°C or higher for a predetermined time. After heating, the furnace lid is lifted by a ceiling crane in the factory, and the heat-treated material is taken out from the furnace body.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the case of heat-treated materials requiring oil quenching, they are lifted from a vertical furnace along with the furnace lid and immersed from the bottom end into an oil tank of sufficient depth for oil quenching. At this time, flames spread outwards, and the more heat-treated materials suspended from the furnace lid, the wider the flame spreads. Furthermore, in the case of heat-treated materials with a hollow, trumpet-shaped design, such as engine shaft parts, the flames spread not only outwards but also upwards through the hollow section. Therefore, there is a limit to the number of heat-treated materials that can be heat-treated and oil-quenched at one time. In addition, the wide spread of flames can cause problems such as interference with electrical equipment in the factory surrounding the oil tank and danger to workers.

[0006] The present invention has been made in view of the above circumstances, and its objective is to provide an oil quenching system that suppresses the spread of flames when the heat treatment material is immersed in an oil bath during the process of moving the heat treatment material removed from a vertical furnace to an oil bath for oil quenching. [Means for solving the problem]

[0007] The oil quenching system according to the present invention is an oil quenching system that performs oil quenching by moving a material to be heat treated from a vertical furnace to an oil tank, and includes a moving means that engages with the lid of the vertical furnace suspended below a rod-shaped steel material so as to extend vertically, and lifts the material to be heat treated from inside the vertical furnace, moves it to directly above the upper opening of the oil tank, and lowers it so as to immerse it in the oil tank, and includes a hood member that is positioned at the upper opening of the oil tank and is given an annular portion having a cross-sectional shape that extends upward so as to extend the wall portion of the oil tank upward and into which the lid can be fitted, and is characterized in that the lid is fitted into the annular portion of the hood member and lowered.

[0008] According to these features, the hood component and lid are positioned to block the path of flame spread, thereby suppressing the spread of flames when the heat-treated material is immersed.

[0009] In the invention described above, the upper end of the annular portion may be characterized by having an expanding portion that widens the opening cross-section upward. Alternatively, the lid may be characterized by lowering the annular portion of the hood member and contacting and placing it on the upper opening of the oil tank. With such features, it is possible to stably operate the lid to fit onto the annular portion of the hood member and place it on the upper opening of the oil tank while suppressing the spread of flames when the heat-treated material is immersed.

[0010] In the invention described above, the hood member may be characterized by having an opening connected to a wet scrubber and drawing in flames from the upper part of the oil tank. Alternatively, the hood member may be characterized by having a tubular passage along its annular outer circumference and being connected to the wet scrubber, with a plurality of openings penetrating the hood member that connect the tubular passage to the inside of the hood member. Furthermore, the tubular passages may be provided above and below the hood member and connected to the wet scrubber, respectively. Such features allow for safer and more effective suppression of flame spread.

[0011] In the invention described above, the steel material may be characterized by being hollow. Furthermore, the steel material may be characterized by being suspended in multiples from the lid. Such features allow for the suppression of flame spread, even in cases where flames tend to become larger. [Brief explanation of the drawing]

[0012] [Figure 1] This is a side view (partially a block diagram) of an oil quenching system in one embodiment of the present invention. [Figure 2] This is a side cross-sectional view of the main part of an oil quenching system. [Figure 3] This is a side view showing the process of immersing steel materials in an oil tank. [Figure 4] This is a side cross-sectional view showing the process of immersing steel materials in an oil tank. [Figure 5] This is a cross-sectional view showing an example of a steel material that has undergone heat treatment. [Figure 6] This is a side cross-sectional view of a key part of another example of an oil quenching system. [Modes for carrying out the invention]

[0013] The oil quenching system in this embodiment will be explained with reference to Figures 1 and 2.

[0014] As shown in Figure 1, the oil quenching system 1 is a system that uses a rod-shaped steel material M as the material to be heat-treated, and performs oil quenching after heating and holding. The oil quenching system 1 comprises a vertical furnace 2 for heating and holding the steel material M, a lid 10 of the vertical furnace 2 with the steel material M suspended below, an overhead crane 3 which is a means of moving the steel material M together with the lid 10 and engages with the upper engaging portion 11 of the lid 10, and an oil tank 4 in which the steel material M is immersed. With this, the oil quenching system 1 can remove the steel material M by pulling it up from inside the vertical furnace 2, move it directly above the upper opening 5 (see Figure 2) of the oil tank 4, and then lower the steel material M and immerse it in the quenching oil 6 (see Figure 2) in the oil tank 4 to perform oil quenching.

[0015] Referring also to Figure 2, the upper part of the oil tank 4 is provided with a hood member 20 that extends upward from the wall portion of the oil tank 4. The hood member 20 has an annular portion 21 having a cross-sectional shape that allows the lid 10 to be fitted inside. A plate-like body 26 is fixed to the inner circumferential surface of the annular portion 21, defining the space inside the hood member 20. In this embodiment, the lid 10 has an outer circumferential surface 12 that is circular when viewed from above, and the annular portion 21 and plate-like body 26 of the hood member 20 have an annular shape along the outer circumferential surface 12. The fitting between the outer circumferential surface 12 of the lid 10 and the plate-like body 26 has a gap that does not hinder the vertical movement of the lid 10.

[0016] The hood member 20 includes an expanding portion 22 that tapers upward from the upper end of the annular portion 21, thereby increasing its opening cross-section. The expanding portion 22 allows the lid 10, which is lowered from above, to be quickly guided into the interior of the annular portion 21.

[0017] The hood member 20 further includes an enlarged annular section 23, which has a larger cross-sectional shape than the annular section 21, extending from the lower end of the annular section 21 to the upper end of the oil tank 4. A plate-like body 26 extends from above along the inner circumference of the enlarged annular section 23 without any steps or inclines, forming a tubular passage 26a in the cavity between the annular section 21 and the enlarged annular section 23. In other words, the tubular passage 26a is provided along the annular outer circumference of the annular section 21. Near the lower end of the plate-like body 26, there are multiple openings 27a (see Figure 6) that communicate with the tubular passage 26a from the inner circumference. A through hole is provided in a part of the enlarged annular section 23 that communicates with an external pipe 24, and is connected to the wet scrubber 25 via the pipe 24. In other words, the space inside the plate-like body 26 communicates with the tubular passage 26a inside the enlarged annular portion 23 via the opening 27a, and is further connected to the wet scrubber 25 via the piping 24 from the tubular passage 26a. The wet scrubber 25 can suck up exhaust gas containing pollutants such as dust and bring it into contact with a cleaning liquid such as water to capture the pollutants in the cleaning liquid. Therefore, if the exhaust gas contains flames from oil that has gasified, misted, and ignited as pollutants, the wet scrubber 25 can extinguish the flames with the cleaning liquid while cooling and capturing the oil.

[0018] The lid 10 includes an upper engaging portion 11 having an annular engaging ring 11a engaged by a lifting tool 3a of the ceiling crane 3 at its upper part. Further, a center shaft 14 for suspending the steel material M is implanted in the lid 10 so as to project downward from the center of its lower surface 13. The lid 10 further includes a plurality of multi-wire suspension shafts 15 around the center shaft 14. At the lower ends of the center shaft 14 and the multi-wire suspension shafts 15, holes for inserting pins horizontally are provided, and a substantially cylindrical lifting jig 16 having pin holes called glasses can be engaged with pins. A hole for inserting a pin is also provided at the upper end of the steel material M, and the pin can be inserted through and engaged with the other pin hole of the lifting jig 16. That is, the center shaft 14 or the multi-wire suspension shafts 15 and the steel material M are engaged via the lifting jig 16 so as to be rotatable about pins at both ends of the lifting jig 16 like a universal joint. Thereby, the bar-shaped steel material M is suspended below the lid 10 so as to extend in the vertical direction.

[0019] Next, the operation of the oil quenching system 1 will be described with reference to FIGS. 3 and 4.

[0020] As shown in FIG. 3(a), the steel material M taken out from the vertical furnace 2 is moved directly above the upper opening 5 of the oil tank 4 while being suspended by the lid 10. Further, as shown in FIG. 3(b), the steel material M is lowered and immersed in the quenching oil 6 of the oil tank 4. Then, the cooling of the steel material M is started, and the oil temperature around the steel material M rises.

[0021] As shown in Fig. 4(a), when the steel material M is further lowered, the lid 10 is guided into the inside of the annular portion 21 by the expanding portion 22, fitted into the annular portion 21, and lowered. At this time, many parts of the steel material M are immersed in the quenching oil 6, and the oil temperature around the steel material M tends to rise. And in some cases, the quenching oil 6 is partially gasified and atomized to catch fire and generate flames. Here, as described above, the lid 10 is fitted into the annular portion 21, and the generated flames are stopped at the lower part of the lid 10 and inside the hood member 20. More specifically, the space surrounded by the lid 10, the plate-like body 26, the oil tank 4, and the quenching oil 6, as well as the inside of the tubular passage 26a, the pipe 24, and the wet scrubber 25, can confine the flames. That is, the lid 10 and the hood member 20 are arranged so as to block the path where the flames spread, and the spread of the flames during the immersion of the heat-treated material can be suppressed. Also, in the enlarged annular portion 23 below the annular portion 21, the flames are sucked from the pipe 24 to the wet scrubber 25 through the tubular passage 26a. Thereby, the flames can be sucked at the upper part of the oil tank 4 to further suppress the spread of the flames.

[0022] As shown in Fig. (b) of the same figure, when the steel material M is further lowered, the lid 10 is lowered while confining the flames between it and the hood member 20. At this time, most of the steel material M comes to be immersed in the quenching oil 6, and the temperature also drops so that almost no flames are generated. Eventually, the lid 10 abuts on and is placed on the upper opening 5 of the oil tank 4, and the cooling of the steel material M by the quenching oil 6 continues.

[0023] As described above, by providing the hood member 20, the spread of the flames from the oil tank 4 can be suppressed.

[0024] As shown in Figure 5, the steel material M to be heat-treated may be hollow. In the case of a hollow shape, when immersed in the quenching oil 6, the quenching oil 6 is heated and rises inside, making it easier to gasify and mist, and thus intensifying the flame. In particular, as shown in the same figure, if the steel material M is a material for an aircraft engine shaft, it is hollow and has a trumpet-shaped inclined section M1 at the bottom. In this case, the heating and rise of the quenching oil 6 is further promoted, making the flame even more intense. Even in such cases, the oil quenching system 1 can contain the flame inside the hood member 20, thereby suppressing the spread of the flame.

[0025] Furthermore, as described above, the lid 10 is equipped with multiple shafts 15 for suspending multiple steel materials (see Figure 2). This means that multiple steel materials M can be suspended from the lid 10 simultaneously and oil-quenched at the same time. When multiple materials are oil-quenched simultaneously in this manner, the temperature of the quenching oil 6 tends to rise, and the resulting flames become more intense. Even in such cases, the oil quenching system 1 can suppress the spread of flames.

[0026] As shown in Figure 6, for example, tubular passages can be provided above and below the hood member 20' and connected to the wet scrubber 25, respectively. In other words, flames can be individually drawn in from multiple locations at different heights. In this example, the hood member 20' is provided with a tubular passage 26a similar to the one described above, and also has an upper tubular passage 26b located above the tubular passage 26a. The upper tubular passage 26b is provided along the annular outer circumference of the annular portion 21 and communicates with multiple openings 27b provided around the inner surface of the plate-shaped portion 26. The upper tubular passage 26b is also connected to the wet scrubber 25 via an upper pipe 24b provided at a higher position than the pipe 24. On the other hand, the lower tubular passage 26a similarly communicates with the inner side of the plate-shaped portion 26 via multiple openings 27a provided around it, and is also connected to the wet scrubber 25 via the lower pipe 24. Furthermore, piping 24 and upper piping 24b merge before connecting to the wet scrubber 25, and butterfly valves 28a and 28b are provided upstream of the merging point, respectively. By operating the butterfly valves 28a and 28b, it is possible to select to open or close piping 24 and 24b, respectively. With this configuration, flames generated inside the hood member 20' can be individually drawn in through openings 27a and 27b, which are at different heights, and guided to the wet scrubber 25.

[0027] With such a hood member 20', flames that tend to spread at a high position can be drawn in through the upper tubular passage 26b from the upper opening 27b. For example, when oil quenching a hollow steel material M (see Figure 5), flames erupt from the upper opening of the steel material M and tend to spread outward at a high position close to the lid 10. In such cases, a hood member 20' that can draw in flames at a high position is particularly suitable. When the lid 10 is at a high position, it is preferable to draw in flames through both the piping 24 and the upper piping 24b to efficiently draw in the flames. In other words, the spread of flames can also be suppressed by an oil quenching system equipped with such a hood member 20'.

[0028] Although representative embodiments of the present invention and modifications thereof have been described above, the present invention is not necessarily limited thereto, and those skilled in the art will be able to find various alternative embodiments and modifications without departing from the spirit of the present invention or the scope of the attached claims. [Explanation of Symbols]

[0029] 1. Oil quenching system 2 Vertical furnace 3. Overhead crane (means of transport) 4 Oil tank 10 Lid 20 Hood components M Steel material (heat treated material)

Claims

1. An oil quenching system in which the heat-treated material removed from a vertical furnace is moved to an oil tank and oil quenched, The apparatus is equipped with a moving mechanism that engages with the lid of the vertical furnace, which is suspended from the lower part of a rod-shaped steel material so as to extend vertically, and lifts the material to be heat-treated from inside the vertical furnace, moves it to directly above the upper opening of the oil tank, and lowers it so that it is immersed in the oil tank. An oil quenching system characterized by including a hood member positioned at the upper opening of the oil tank, extending upward from the wall of the oil tank, and having an annular portion with a cross-sectional shape that allows the lid to be fitted inside, wherein the lid is fitted into the annular portion of the hood member and lowered.

2. The oil quenching system according to claim 1, characterized in that the upper end of the annular portion has an expanding portion that widens the opening cross-section upward.

3. The oil quenching system according to claim 2, characterized in that the lid is placed in contact with the upper opening of the oil tank by lowering the annular portion of the hood member.

4. The oil quenching system according to claim 1, characterized in that the hood member has an opening connected to a wet scrubber and sucks in flames from the top of the oil tank.

5. The oil quenching system according to claim 4, characterized in that the hood member has a tubular passage along its annular outer circumference and is connected to the wet scrubber, and a plurality of openings are provided through the hood member, connecting the tubular passage to the inside of the hood member.

6. The oil quenching system according to claim 5, characterized in that the tubular passages are provided above and below the hood member and are connected to the wet scrubber, respectively.

7. The oil quenching system according to one of claims 1 to 6, characterized in that the steel material has a hollow shape.

8. The oil quenching system according to claim 7, characterized in that a plurality of the steel materials are suspended from the lid.

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