Stirring shaft and heat exchange device equipped with the same

Abstract

To enable heating and agitation of an article to be processed by an agitation shaft of a temperature as high as possible while transfer of heat of a heat medium to a part such as a bearing part weak to heat is made difficult.SOLUTION: An agitation shaft 50 is provided with a columnar shaft 51, a center flow path 52 passing through the shaft center of the columnar shaft 51, an agitation blade 53 extending outside the outer periphery of the columnar shaft 51 in a radial direction, and an inner pipe 19 inserted into the center flow path 52, communicated at one end with the center flow path 52, and having heat medium supply / discharge paths 19a and 55a through which the heat medium is supplied or discharged from the other end at the shaft center. An inner pipe outer peripheral flow path 21 communicated with the center flow path 52 and a cylindrical vacuum part 22 covering the inner pipe outer peripheral flow path 21 and having a sealed vacuum space formed therein are provided between outside the inner pipe 19 and the outer periphery of the inner pipe 19.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a stirring shaft having a double-tube structure in which an inner tube is inserted into a central flow path and a heat exchanger equipped with the same.

Background Art

[0002] Conventionally, there is known a heat medium passing shaft of a type in a double-tube structure mixer stirring shaft having an inner tube and an outer tube constituting the shaft end of the stirring shaft, through which a heat medium is fed through the shaft inner tube and returned through an annular gap between the inner tube and the outer tube (for example, Patent Document 1).

[0003] In this type of double-tube structure, heat of the stirring shaft is also transmitted to bearings and gland packings that rotatably support the stirring shaft and are relatively weak against high temperatures, so there is a problem that the heating temperature of the stirring shaft is limited.

[0004] Therefore, in this heat medium passing shaft, a heat insulating sleeve filled with a heat insulating material is disposed in contact with the inner surface of the outer tube in the annular gap to make it difficult for the heat of the stirring shaft to be transmitted to the bearings and gland packings. It is also known to provide a metal case capable of exhausting gas instead of the heat insulating sleeve and evacuating the inside to a vacuum.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] However, as in Patent Document 1, filling the sleeve with a heat insulating material is troublesome, and there is a problem that the overall structure becomes complicated in order to make the sleeve have a structure capable of being evacuated to a vacuum state.

[0007] The present invention has been made in view of such a point, and its object is to heat and stir an object to be treated with a stirring shaft at as high a temperature as possible while making it difficult to transfer the heat of a heat medium to a heat-sensitive part such as a bearing part.

Means for Solving the Problems

[0008] In order to achieve the above object, in the first invention, a heat medium flow path for circulating a heat medium inside is formed, and a stirring shaft provided with stirring blades on the outer periphery is targeted. The above stirring shaft has a columnar shaft portion, a central flow path passing through the axis of the columnar shaft portion, stirring blades extending radially outward from the outer periphery of the columnar shaft portion, and an inner pipe inserted into the central flow path and having inside it heat medium supply / discharge paths (19a, 55a) one end of which communicates with the central flow path and from the other end of which the heat medium is supplied or discharged. Outside the inner pipe, there are provided an outer peripheral flow path of the inner pipe communicating with the central flow path between the outer periphery of the inner pipe and a cylindrical vacuum portion (22) in which a vacuum space sealed inside is formed in the region of the columnar shaft portion rotatably supported by a bearing portion and covering the outer periphery of the outer peripheral flow path of the inner pipe.

[0009] According to the above configuration, a high-temperature heat medium flows through the heat medium supply / discharge paths and the outer peripheral flow path of the inner pipe, but heat is less likely to be transferred to the columnar shaft portion on the outer periphery thereof by the vacuum portion in which a cylindrical sealed vacuum space is formed by welding or the like so as to cover the periphery thereof. Therefore, even when a heat medium at as high a temperature as possible is circulated inside the stirring shaft, damage to support portions such as bearing portions due to heat can be avoided.

[0010] In the second invention, in the first invention, The vacuum section (22) has a first pipe (19d) sealed and welded between the flange sections (19b, 19c) at both ends, and a second pipe (19e) with an outer diameter larger than that of the first pipe (19d).

[0011] The heat exchanger of the third invention the stirring shaft of the first or second invention, a rotary joint connected to the stirring shaft, supplying a heat medium to one of the central flow path and the heat medium supply / discharge path, and recovering the heat medium that has returned from the other of the central flow path and the heat medium supply / discharge path, a casing that rotatably supports the stirring shaft via a bearing section, and a heat medium circulation device that supplies and recovers the heat medium via the rotary joint.

[0012] According to the above configuration, even if a high-temperature heat medium is circulated from the rotary joint, heat is hardly transmitted to the bearing section or the like. Therefore, while preventing damage to the bearing section or the like due to heat, the object to be processed can be effectively heated and stirred while being stirred.

Advantages of the Invention

[0013] As described above, according to the present invention, it is possible to heat and stir the object to be processed with a stirring shaft at as high a temperature as possible while making it difficult for the heat of the heat medium to be transmitted to a heat-sensitive part such as a bearing section.

Brief Description of the Drawings

[0014]

Figure 1

Figure 2

Figure 3

Embodiments for Carrying Out the Invention

[0015] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0016] -Configuration of Kneader- Figure 2 shows a kneader 10 as a heat exchange device according to the present invention. This kneader 10 has, for example, an airtight box-shaped casing 1. A supply port 2 for the object to be processed (raw material) A is provided at the upper part of one end of this casing 1, and a discharge port 3 is provided at the lower part of the other end. It is a continuous kneader. Further, a jacket 4 is formed on the outer periphery of the casing 1, and a heat medium C can flow through the jacket 4 by a known heat medium circulation device 20.

[0017] In the casing 1, for example, a pair of stirring shafts 50 are rotatably supported by a motor (not shown). For example, one end side is pivotally supported by a gland packing 7, and the above motor is connected. The other end is pivotally supported by the gland packing 7 and a bearing portion 8, and a rotary joint 14 for supplying and recovering the heat medium C from the heat medium circulation device 20 is connected. On the rotary joint 14 side of the stirring shaft 50, for example, one reverse feed screw paddle 16 is externally fitted. A plurality of forward feed screw paddles 18 are externally fitted on the motor side of the stirring shaft 50. The shape of the forward feed screw paddle 18 is not particularly limited. The reverse feed screw paddle 16 may be one in which the forward feed screw paddle 18 is attached in the reverse direction.

[0018] As shown in Figure 2, the stirring shaft 50 has a heat medium flow path formed inside for the heat medium C from the heat medium circulation device 20 to flow through, and stirring blades 53 for stirring the object to be processed A are provided on the outer periphery. The heat medium flow path includes a central flow path 52, a blade side flow path 54, a heat medium supply and discharge path 55a, etc., which will be described later.

[0019] Specifically, the stirring shaft 50 includes a columnar shaft portion 51 and a central flow path 52 passing through the axis of the columnar shaft portion 51. At the central portion in the longitudinal direction of the columnar shaft portion 51, a plurality of stirring blades 53 are formed to project, which extend radially outward from the outer periphery of the columnar shaft portion 51 and are provided at intervals in the axial direction. In the stirring blade 53, a blade-side flow path 54 is formed, one end of which communicates with the central flow path 52 and the other end of which communicates with the central flow path 52 through the inside of the stirring blade 53. However, the shape of the stirring blade 53 is not particularly limited. For example, it may be configured as a continuous spiral shape, and the blade-side flow path 54 may not be formed.

[0020] A hollow shaft-shaped (tubular) partition member 55 is inserted into the central flow path 52. As shown in FIG. 1, the partition member 55 is connected to the inner pipe 19 of the rotary joint 14 by welding, for example, and is supported integrally with the stirring shaft 50 in rotation. The partition member 55 has a heat medium supply / discharge path 55a communicating with the heat medium supply / discharge path 19a extending to the center of the inner pipe 19 on its axis. The proximal end side of the inner pipe 19 is connected to the rotary joint 14 and the heat medium C is supplied, and the heat medium C is discharged from the other end of the open partition member 55. The partition member 55 is inserted into the central flow path 52 and serves to partition the central flow path 52 into an upstream side and a downstream side at positions corresponding to the stirring blades 53, and to communicate the upstream side with one end of the blade-side flow path 54 and the downstream side with the other end of the blade-side flow path 54.

[0021] The tip of the central flow path 52 does not extend up to the position of the motor-side gland packing 7. Therefore, the motor-side gland packing 7 is hardly affected by the heat of the heat medium C flowing inside the stirring shaft 50.

[0022] However, as shown enlarged in FIGS. 1 and 3, an inner pipe outer peripheral flow path 21 communicating with the central flow path 52 is formed between the outer periphery of the inner pipe 19 on the rotary joint 14 side, so the inside of the gland packing 7 on the rotary joint 14 side is easily affected by the heat medium C.

[0023] Therefore, in this embodiment, the outer periphery of the outer peripheral flow path 21 of the inner pipe is covered by a cylindrical vacuum portion 22 in which a vacuum space is formed inside. For example, this cylindrical vacuum portion 22 has an inner diameter substantially the same as the inner diameter of the central flow path 52, thereby forming a space communicating with the outer flow path formed between the partition member 55 and the central flow path 52 between the outer peripheral surface of the inner pipe 19. Its outer diameter is set to a size that can form an appropriate vacuum space inside. This vacuum space is sealed to be, for example, 10 -2 ~10 -4 Pa during the molding of the inner pipe 19. For example, it is advisable to weld a first pipe 19d having an inner diameter equal to that of the central flow path 52 and a second pipe 19e having an outer diameter larger than that of the first pipe 19d in a sealed manner between the flange portions 19b and 19c at both ends.

[0024] Furthermore, a gap is secured to form an inner air layer 23 continuous in the circumferential direction between the outer peripheral surface of the vacuum portion 22 and the inner peripheral surface of the cylindrical shaft portion 51. This gap is secured by setting the outer diameter of the second pipe 19e to be smaller than the inner diameter of the through hole (central flow path 52) formed in the cylindrical shaft portion 51.

[0025] Moreover, the cylindrical shaft portion 51 corresponding to the outer periphery of the vacuum portion 22 is covered by a cylindrical sleeve 24 that forms a gap continuous in the circumferential direction between the outer periphery of this cylindrical shaft portion 51. For example, by making the inner diameter at the middle in the longitudinal direction of the cylindrical sleeve 24 larger than the both ends in the longitudinal direction, a gap is secured between the outer periphery of the cylindrical shaft portion 51. An outer air layer 25 continuous in the circumferential direction is formed by this gap.

[0026] -Operation of the kneader- Next, the operation of the kneader 10 according to this embodiment will be described.

[0027] When raw material A is supplied into the casing 1 from the supply port 2, the raw material A is sent toward the discharge port 3 side by the feeding action of the forward feeding screw paddle 18, and is kneaded while being heated under the kneading action caused by the rotation of the stirring blade 53, and then is discharged from the discharge port 3 as a product (kneaded object to be processed) B. At this time, the supply amount of the raw material A is adjusted to adjust the heating degree.

[0028] During this period, a heat medium C is circulated in the jacket 4 from an inlet / outlet (not shown) in the casing 1 to heat the raw material A. For example, the inside of the casing 1 is heated to about 350°C. Further, as shown in FIG. 2, the heat medium C is also supplied to the heat medium supply / discharge passage 55a through the heat medium supply / discharge passage 19a of the inner pipe 19 from the rotary joint 14, and from the depth of the central flow path 52, through the outer periphery of the partition member 55, the blade side flow path 54, and the outer pipe outer periphery flow path 21 of the inner pipe 19, and then returns to the rotary joint 14 and is returned to the heat medium circulation device 20.

[0029] In this embodiment, in order to heat the stirring shaft 50 to about 350°C, which is the same as the inside of the casing 1, a high-temperature heat medium flows through the heat medium supply / discharge passage 19a and the outer pipe outer periphery flow path 21 of the inner pipe 19, but heat is less likely to be transmitted to the columnar shaft portion 51 on the outer periphery thereof due to the cylindrical vacuum portion 22 covering the periphery thereof. Moreover, since a gap for forming an inner air layer 23 is provided on the outer periphery of the vacuum portion 22, heat of the vacuum portion 22 is even less likely to be transmitted to the columnar shaft portion 51.

[0030] Further, due to the outer air layer 25 formed in the gap on the inner periphery of the cylindrical sleeve 24, heat from the columnar shaft portion 51 is less likely to be transmitted to the gland packing 7 and the bearing portion 8.

[0031] Therefore, even if a high-temperature heat medium C is circulated through the heat medium supply / discharge passage 19a and the outer pipe outer periphery flow path 21 of the inner pipe 19 in order to heat the stirring shaft 50 to about 350°C, which is the same as the inside of the casing 1, heat is less likely to be transmitted to the gland packing 7 and the bearing portion 8 that support the outer periphery thereof. For this reason, even if a heat medium at as high a temperature as possible is circulated throughout the inside of the stirring shaft 50, damage to the support portions such as the gland packing 7 and the bearing portion 8 due to heat can be avoided.

[0032] Thus, in this embodiment, a zone where heat is difficult to transfer to the outer periphery of the stirring shaft 50 can be intentionally set around the vacuum section 22. Since the inner pipe 19 is composed of a pipe, its length, outer diameter, material, etc. can be arbitrarily changed. Also, since the inner pipe 19 can be replaced even during consumption, the replacement can be performed easily and inexpensively. Furthermore, since the heat insulation performance evaluation of the stirring shaft 50 alone can be carried out, troubles after installation can be effectively prevented. Also, in the stirring shaft 50, a vacuum layer and an air layer can be secured, so that the heat insulation effect can be easily improved.

[0033] As described above, according to the stirring shaft 50 according to this embodiment, while making it difficult to transfer the heat of the heat medium to heat-sensitive parts such as the gland packing 7 and the bearing portion 8, the object to be processed can be heated and stirred by the stirring shaft 50 at as high a temperature as possible.

[0034] (Other Embodiments) The present invention may be configured as follows with respect to the above embodiment.

[0035] That is, in the above embodiment, in the kneader 10, two stirring shafts 50 are arranged in parallel, but only one stirring shaft 50 may be used.

[0036] In the above embodiment, the heat medium C supplied from the rotary joint 14 is supplied into the central flow path 52 through the heat medium supply / discharge path 19a and the heat medium supply / discharge path 55a inside the partition member 55. However, the heat medium C supplied into the central flow path 52 on the outer periphery of the inner pipe 19 and flowing toward the motor side through the blade side flow path 54 along the outer peripheries of the inner pipe 19 and the partition member 55 may be discharged to the rotary joint 14 side through the heat medium supply / discharge path 55a of the partition member 55 and the heat medium supply / discharge path 19a of the inner pipe 19.

[0037] Note that the above embodiments are essentially preferred examples and are not intended to limit the scope of the present invention, its applications, or uses.

Explanation of Reference Numerals

[0038] 1 Casing 2 Feed port 3 Discharge port 4 Jacket 7 Gland packing 8 Bearing part 10 Kneader (heat exchanger) 14 Rotary joint 16 Reverse feed screw paddle 18 Forward feed screw paddle 19 Inner pipe 19a Heat medium supply and discharge path 19b, 19c Flange part 19d First pipe 19e Second pipe 20 Heat medium circulation device 21 Outer peripheral flow path of inner pipe 22 Vacuum part 23 Inner air layer 24 Cylindrical sleeve 25 Outer air layer 50 Stirring shaft 51 Cylindrical shaft part 52 Central flow path 53 Stirring blade 54 Blade side flow path 55 Partition member 55a Heat medium supply and discharge path A Raw material B Product C Heat medium

Claims

1. A stirring shaft having a heat medium flow path for circulating a heat medium therein and provided with stirring blades on the outer periphery, comprising: a cylindrical shaft portion; a central flow path passing through the axis of the cylindrical shaft portion; stirring blades extending radially outward from the outer periphery of the cylindrical shaft portion; an inner pipe inserted into the central flow path and having therein a heat medium supply / discharge path (19a, 55a) through which one end communicates with the central flow path and the heat medium is supplied or discharged from the other end; outside the inner pipe, there is provided a cylindrical vacuum portion (22) having an outer peripheral flow path of the inner pipe communicating with the central flow path and a vacuum space sealed inside in a region of the cylindrical shaft portion covering the outer periphery of the outer peripheral flow path of the inner pipe and rotatably supported by a bearing portion; the vacuum portion (22) has a first pipe (19d) sealed and welded between flange portions (19b, 19c) at both ends and a second pipe (19e) having an outer diameter larger than that of the first pipe (19d). The stirring shaft is characterized by the above.

2. The stirring shaft according to Claim 1, a rotary joint connected to the stirring shaft for supplying a heat medium to one of the central flow path and the heat medium supply / discharge path and recovering the heat medium returned from the other of the central flow path and the heat medium supply / discharge path; a casing rotatably supporting the stirring shaft via the bearing portion; and a heat medium circulation device for supplying and recovering the heat medium via the rotary joint. The heat exchange device is characterized by the above.

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