JP5759674B2 - Stirring shaft for horizontal stirring system - Google Patents

Description

  The present invention relates to a stirring shaft for a horizontal type stirring system. More specifically, the present invention relates to a stirring shaft that can be installed horizontally in a horizontal stirring system and that prevents bending during rotation.

  Conventionally, a horizontal stirring system such as a horizontal methane fermentation system has used a hollow stirring shaft in order to reduce the mass of the stirring shaft. For example, the conventional horizontal methane fermentation system shown in FIG. 1 includes a fermenter 10 and a stirring shaft 11, and the stirring shaft 11 is installed in the fermenter 10 via a shaft seal 14. When the kind of the substrate put into the fermenter 10 is constant, the specific gravity difference between the substrate and the stirring shaft 11 can be specified. Therefore, since the weight 16 of the stirring shaft 11 can be specified by the diameter and thickness of the stirring shaft 11 in accordance with the required rotational torque, the diameter and thickness of the stirring shaft 11 can be adjusted in consideration of the buoyancy 17.

  However, if the substrate is not constant, for example, if fiber, plastic, rubber, leather, glass, vinyl, garbage bag, stone, ceramics, metal, etc. are contained in the fermenter 10, the substrate and the stirring shaft 11 It becomes difficult to specify the specific gravity difference.

  Thus, if the specific gravity difference between the substrate and the stirring shaft 11 is significantly different from that at the time of design, the balance between the buoyancy 17 and the own weight 16 of the stirring shaft 11 is lost, and the rotational deflection of the stirring shaft increases. As a result, the shaft seal 14 is worn out, an overload is applied to the driving machine 13, and the operation is hindered.

  Patent Document 1 describes a fermenter including a stirring shaft (shaft) that prevents such rotational deflection. The shaft described in Patent Document 1 prevents rotational deflection by a levitation force caused by gas or air filled in a hollow portion.

  However, gas or air in the hollow shaft gives buoyancy to the shaft and is used to detect and prevent damage to the shaft. However, if these gases and moisture coexist, the shaft may be corroded. There is.

  Patent Document 2 describes a long-type (horizontal-type) ice making machine having a rotating shaft. In this apparatus, in order to prevent bending of the rotating shaft to which the ice scraping member is attached, the rotating shaft is configured to receive buoyancy corresponding to its own weight from the liquid to be cooled.

Special table 2008-528260 Japanese Patent Laid-Open No. 9-296973

  An object of the present invention is to provide a stirring shaft that can be horizontally installed and prevents rotational deflection during operation, regardless of the specific gravity of the substrate stirred by the horizontal stirring system.

  The present invention provides a stirring shaft for a horizontal type stirring system, wherein the stirring shaft is a stirring shaft member formed of a hollow cylindrical body; at least one stirring member provided on an outer peripheral surface of the stirring shaft member; and the stirring Provided on at least one of the outer peripheral surface and the end surface of the shaft member, and comprising at least two nozzles that allow introduction of the liquid material into the stirring shaft member and discharge of the liquid material from the stirring shaft member .

  In one embodiment, the introduction of the inert gas into the stirring shaft member and the discharge of the inert gas from the stirring shaft member are further performed on at least one of the outer peripheral surface and the end surface of the stirring shaft member. At least two nozzles are provided that allow.

  In one embodiment, the inert gas is nitrogen.

  In one embodiment, the liquid is water.

  Moreover, this invention provides the horizontal installation type stirring system provided with the stirring shaft for said horizontal installation type stirring systems, and a stirring tank.

  In one embodiment, the horizontal agitation system is a methane fermentation system.

  Furthermore, the present invention provides a method for preventing the bending of a stirring shaft for a horizontal stirring system, wherein the method introduces a liquid material into the stirring shaft member constituting the stirring shaft, or It includes a step of discharging the liquid material from the inside and adjusting the weight of the stirring shaft.

  In one embodiment, in the step of adjusting the dead weight of the stirring shaft, an inert gas is further introduced into the stirring shaft member or discharged from the stirring shaft member.

  In one embodiment, the inert gas is nitrogen.

  In one embodiment, the liquid is water.

  ADVANTAGE OF THE INVENTION According to this invention, regardless of the specific gravity of the board | substrate stirred with a horizontal installation type stirring system, a horizontal installation is possible and the stirring shaft which can prevent the rotation bending at the time of a driving | operation can be provided.

It is a figure which shows the embodiment using the conventional stirring shaft as a stirring shaft of a methane fermentation system. It is a figure which shows one embodiment using the stirring shaft of this invention as a stirring shaft of a methane fermentation system.

(A) Stirring shaft for a horizontal stirring system FIG. 2 shows a stirring shaft of a methane fermentation system which is an embodiment of the stirring shaft of the present invention. The stirring shaft 21 of the present invention includes a stirring shaft member 22, a stirring member (not shown), and a nozzle 281.

  The stirring shaft member 22 is a member that forms the basis of the stirring shaft 21 of the present invention, and is formed of a hollow cylinder. The material of the stirring shaft member 22 is not particularly limited, but is preferably made of metal from the viewpoint of strength. In addition, the stirring shaft member 22 preferably has a cylindrical shape in order to perform a rotational motion.

  The length of the stirring shaft member 22 can be appropriately set depending on the size of the stirring tank to be installed. Preferably it may be 10 m or more. Moreover, the thickness (outer diameter) of the stirring shaft member 22 can also be set as appropriate depending on the size of the stirring tank to be installed. Preferably it may be 50 cm to 150 cm.

  At least one stirring member is provided on the outer peripheral surface of the stirring shaft member 22. The stirring member is generally a stirring blade, and the size, number, shape, and the like of the stirring blade can be appropriately set depending on the type of the substrate to be stirred, the size of the stirring tank, and the like.

  One end face of the both end faces of the stirring shaft member 22 is configured to be connected to a drive unit 23 that transmits a rotational force to the stirring shaft 21 of the present invention.

  A nozzle is provided on at least one of the outer peripheral surface and the other end surface of the stirring shaft member 22. FIG. 2 is an embodiment in which a nozzle is provided on both the outer peripheral surface and the end surface of the stirring shaft member 22. The nozzles 281A and 282A are provided on the outer peripheral surface of the stirring shaft member 22, and the nozzles 281B and 282B are provided on the end surface of the stirring shaft member 22. It is only necessary to provide at least two nozzles, that is, only the nozzles 281A and 281B for introducing and discharging the liquid 211, but it is preferable to further provide the nozzles 282A and 282B for introducing and discharging the inert gas 212. .

  The nozzles 281 </ b> A and 281 </ b> B are provided so that the liquid material 211 can be introduced into the stirring shaft member 22 (hollow portion) and the liquid material 211 can be discharged from the stirring shaft member 22.

  The liquid 211 is not particularly limited as long as it is liquid, and examples thereof include water, oils, and alcohols. The liquid 211 is preferably water because it is inexpensive and easily available and easy to handle.

  The nozzles 282A and 282B are provided for introducing and discharging the inert gas. The inert gas 212 is used to prevent the inside of the stirring shaft member 22 from being corroded by oxygen present inside the stirring shaft member 22 and oxygen dissolved in the liquid 211.

  Examples of the inert gas 212 include nitrogen, argon, carbon dioxide, and the like. The inert gas 212 is easily available, and nitrogen is preferable from the viewpoint of environmental considerations.

(B) Horizontal type stirring system The horizontal type stirring system of this invention is equipped with the stirring shaft and stirring tank of this invention. The capacity, length, depth, and the like of the stirring tank can be appropriately set in consideration of the length of the stirring shaft of the present invention. The stirring system of the present invention is preferably used as a methane fermentation system.

  FIG. 2 shows an embodiment in which the stirring system of the present invention is used as a methane fermentation system as described above. This methane fermentation system includes a fermenter 20 and the stirring shaft 21 of the present invention.

  The stirring shaft 21 has a substantially central portion in the depth direction of the fermentation tank 20 so that a stirring member (not shown) attached to the stirring shaft 21 does not contact the inner wall surface of the fermentation tank 20. It is installed so as to penetrate the fermenter 20 in the direction.

  The stirring shaft 21 is generally installed in the fermenter 20 via a shaft seal 24. A shaft seal 24 is used to prevent wear due to direct contact between the wall surface of the fermenter 20 and the stirring shaft 21 and to prevent leakage of the contents of the fermenter 20.

  The agitation shaft 21 is connected to the drive machine 23 to generate a rotational motion.

(C) Deflection prevention method of stirring shaft for horizontal type stirring system The method of preventing deflection of the stirring shaft for horizontal type stirring system of the present invention introduces a liquid material into the stirring shaft member constituting the stirring shaft, or A step of discharging the liquid material from the inside of the stirring shaft member and adjusting the weight of the stirring shaft is included. Hereinafter, a description will be given with reference to FIG.

  First, before operation (at the time of startup), water is added to the fermenter 20, and when the stirring shaft 21 starts to lift by the buoyancy 27, the liquid is transferred from the nozzle 281A to the stirring shaft 21 (stirring shaft member 22). The introduction of the product 211 (for example, water) is started. Water is supplied to the fermenter 20 until the water level in the fermenter 20 reaches the upper surface of the stirring shaft 21, and the liquid 211 is introduced into the stirring shaft 21 until the stirring shaft 21 becomes horizontal.

  Next, the substrate is added to the fermenter 20 and operation is started. When the substrate is introduced, the specific gravity in the fermenter 20 changes. Therefore, the level of the stirring shaft 21 is periodically measured, and the liquid substance 211 is introduced into the nozzle 281B or discharged from the nozzle 281B. Then, the weight of the stirring shaft 21 is adjusted to maintain the horizontal state.

  At the time of completion of fermentation or maintenance and inspection of the fermenter 20, the substrate 211 in the fermenter 20 may be discharged and the liquid 211 in the stirring shaft 21 may be discharged from the nozzle 281 </ b> B.

  On the other hand, since liquid 211 such as water is introduced into the stirring shaft 21, an inert gas 212 (for example, nitrogen, argon, etc.) is used to prevent corrosion (for example, oxidation prevention) inside the stirring shaft 21 (stirring shaft member 22). It is preferable to introduce carbon dioxide or the like into the stirring shaft 21.

  For example, an inert gas 212 such as nitrogen may be introduced from the nozzle 282A during startup or operation, and the inert gas 212 may be introduced or discharged from the nozzle 282B.

  Hereinafter, the present invention will be described with reference to examples, but the present invention is not limited to the following examples.

Example 1
Using the methane fermentation system shown in FIG. 2, the bending of the central part of the stirring shaft during operation was verified.

  The stirring shaft 21 of the present invention was installed in the fermenter 20 (total length 40 m, diameter 7 m) via a shaft seal 24. Water was added to the fermenter 20 and when the stirring shaft 21 began to float, water (liquid 211) was introduced into the stirring shaft 21 from the nozzle 281A. Water is introduced until the water level in the fermenter 20 reaches the upper surface of the stirring shaft 21, and water is introduced into the stirring shaft 21 until the stirring shaft 21 becomes horizontal at that level, and nitrogen (inert) is added from the nozzle 282A. Gas 212) was introduced.

  Next, a substrate for methane fermentation was added to the fermenter 20, and the operation of the methane fermentation system was started. During operation, the level of the stirring shaft 21 was measured periodically, and water was introduced or discharged from the nozzle 281B and nitrogen was introduced or discharged from the nozzle 282B in order to maintain the level.

  Although the operation exceeded 8000 hours per year for 6 years, the stirring shaft 21 hardly bent.

(Comparative Example 1)
The bending of the central part of the stirring shaft during operation was verified using a methane fermentation system (FIG. 1) having a conventional stirring shaft.

  A conventional stirring shaft 11 was installed in a fermenter 10 (total length 40 m, diameter 7 m) via a shaft seal 14. Water and a substrate for methane fermentation were added to the fermenter 10 to operate the methane fermentation system.

  When the water level of the substrate rose to the upper surface of the stirring shaft, the central portion of the stirring shaft 11 was bent at a maximum of about 90 mm.

  ADVANTAGE OF THE INVENTION According to this invention, regardless of the specific gravity of the board | substrate stirred with a horizontal installation type stirring system, a horizontal installation is possible and the stirring shaft which can prevent the rotation bending at the time of a driving | operation can be provided. Therefore, the present invention is useful in a system that requires stirring, such as a methane fermentation system.

10, 20 Fermenter 11, 21 Agitation shaft 12, 22 Agitation shaft member 13, 23 Drive unit 14, 24 Shaft seal 15, 25 Substrate 16, 26 Self-weight 17, 27 Buoyancy 211 Liquid substance 212 Inert gas 281A, 281B, 282A , 282B nozzle

Claims (6)

A stirring shaft for a horizontal type stirring system,
A stirring shaft member comprising a hollow cylinder;
At least one stirring member provided on the outer peripheral surface of the stirring shaft member; and water, oils, and alcohols provided on either the outer peripheral surface or the end surface of the stirring shaft member; At least two nozzles allowing introduction of at least one liquid selected from the group consisting of:
With
An agitation shaft, wherein at least one of the nozzles is provided on an end surface of the agitation shaft member, and the liquid material inside the agitation shaft member can be discharged from the nozzle on the end surface during operation.   Further, at least two of at least one of the outer peripheral surface and the end surface of the stirring shaft member can introduce an inert gas into the stirring shaft member and discharge the inert gas from the stirring shaft member. The stirring shaft according to claim 1, wherein two nozzles are provided.   The stirring shaft according to claim 2, wherein the inert gas is nitrogen.   The stirring shaft according to any one of claims 1 to 3, wherein the liquid material is water.   A horizontal stirring system comprising the stirring shaft for the horizontal stirring system according to any one of claims 1 to 4 and a stirring tank.   The horizontal stirring system according to claim 5, which is a methane fermentation system.

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