Shovel fixing device of vacuum dryer and vacuum dryer

Abstract

A shovel fixing device for a vacuum dryer and a vacuum dryer are disclosed. A shovel fixing device for a vacuum dryer according to one embodiment comprises a shaft and a shovel connected to the shaft, and comprises a shovel fixing bolt connecting the shaft and the shovel, a first fastening loosening prevention part that is in close contact with the shovel fixing bolt and prevents the shovel fixing bolt from being loosened, a second fastening loosening prevention part that is in close contact with the first fastening loosening prevention part and prevents the shovel fixing bolt from being loosened, and a fixing part that is fitted into the entrance of a fastening groove into which the shovel fixing bolt is inserted and supports the second fastening loosening prevention part. By preventing the shovel from being loosened within the vacuum dryer, internal damage to the vacuum dryer and damage to surrounding equipment can be prevented.

Description

Technology Field

[0001] The present invention relates to a shovel fixing device for a vacuum dryer and a vacuum dryer, and more specifically, to a shovel fixing device for a vacuum dryer and a vacuum dryer that prevents the shovel from loosening within the vacuum dryer, thereby preventing internal damage to the vacuum dryer itself and damage to surrounding equipment. Background Technology

[0002] Unlike primary batteries, which cannot be recharged, secondary batteries refer to batteries that can be charged and discharged.

[0003] A secondary battery can be composed of a cathode material, an anode material, an electrolyte, and a separator. Among these, the cathode material is an important component that determines the performance of the secondary battery, such as capacity and output.

[0004] The manufacturing method of the cathode material can be briefly explained as follows. When powder raw materials such as lithium (Li), nickel (Ni), cobalt (Co), manganese (Mn), and aluminum (Al) are prepared, a drying process is performed to remove moisture contained in the powder raw materials. Subsequently, the materials are fed into a kiln and a calcination process is carried out to prevent quality degradation of the cathode material and improve its characteristics.

[0005] A vacuum dryer includes a shaft that rotates inside a drying chamber equipped with a heating means, and a shovel that is radially connected to the shaft and rotates together with the shaft. The shovel, which rotates by the shaft, can agitate the powdered raw material.

[0006] However, prolonged use of the vacuum dryer may cause the shovel (or shovel fixing bolt) connected to the shaft inside the vacuum dryer to loosen. As a result, serious internal damage to the vacuum dryer itself may occur, and furthermore, damage to surrounding equipment (e.g., Ploughshare Mixer, etc.) may occur.

[0007] As a related prior art, there is Korean Published Patent Application No. 10-2020-0107727 (published September 16, 2020), which discloses technology regarding a powder raw material drying device for manufacturing a cathode material for a secondary battery. Prior art literature

[0008] Republic of Korea Published Patent Application No. 10-2020-0107727 The problem to be solved

[0009] The objective of the present invention is to provide a vacuum dryer shovel fixing device and a vacuum dryer that can prevent the shovel from loosening within the vacuum dryer, thereby preventing internal damage to the vacuum dryer itself and damage to surrounding equipment.

[0010] Another objective of the present invention is to provide a shovel fixing device for a vacuum dryer and a vacuum dryer that can prevent the shovel fixing bolt from loosening and detaching by screw-assembling the shovel fixing bolt between a shaft connecting body and a shovel connecting body and then attaching a plurality of anti-loosening members to the head portion of the shovel fixing bolt.

[0011] The objects of the present invention are not limited to those mentioned above, and other unmentioned objects and advantages of the present invention may be understood from the following description and will be more clearly understood by the embodiments of the present invention. Furthermore, it will be readily apparent that the objects and advantages of the present invention can be realized by the means and combinations thereof set forth in the claims. means of solving the problem

[0012] According to one aspect of the present invention, a shovel fixing device for a vacuum dryer can be provided that prevents the shovel from being loosened within the vacuum dryer, thereby preventing internal damage to the vacuum dryer itself and damage to surrounding equipment.

[0013] A shovel fixing device for a vacuum dryer according to one embodiment comprises: a shaft that rotates axially within a drying chamber; and a shovel that is connected to the shaft in a radial direction and stirs powder raw materials contained in the drying chamber, wherein the shovel fixing device for a vacuum dryer comprises: a shovel fixing bolt that connects the shaft and the shovel; a first fastening loosening prevention part that is in close contact with the shovel fixing bolt and prevents the fastening of the shovel fixing bolt from loosening; a second fastening loosening prevention part that is in close contact with the first fastening loosening prevention part and prevents the fastening of the shovel fixing bolt from loosening; and a fixing part that is fitted and coupled at the entrance of a fastening groove into which the shovel fixing bolt is inserted at a set distance from the shovel fixing bolt and supports the second fastening loosening prevention part.

[0014] According to one embodiment, the shaft includes a shaft connecting body extending radially from the outer diameter of the shaft, and the shovel includes a shovel body for stirring powder raw materials; and a shovel connecting body having one end connected to the shovel body and the other end connected to the shaft connecting body.

[0015] According to a preferred embodiment, the shovel fixing device may include three shovel fixing bolts that are spaced apart from each other and fastened in series along the longitudinal direction of the shovel connecting body, three first fastening anti-loosening parts that support each of the three shovel fixing bolts, three second fastening anti-loosening parts, and three fixing parts.

[0016] According to one embodiment, the shovel fixing bolt comprises: a head portion that is received at the entrance of the fastening groove and has one surface in close contact with the first fastening anti-loosening portion; a body portion that extends by a set length from the other surface of the head portion and is inserted through the shovel connecting body; and a screw portion that is connected to the end of the body portion and is screw-fastened to the shaft connecting body.

[0017] According to one embodiment, the first fastening anti-loosening part may be a plate made of an elastic material that has one surface in close contact with the head portion of the shovel fixing bolt and supports the shovel fixing bolt, and the second fastening anti-loosening part may be a plate made of a rigid material that has one surface in close contact with the other surface of the first fastening anti-loosening part and has its position constrained by the fixing part supporting the other surface.

[0018] According to one embodiment, the first fastening anti-loosening part and the second fastening anti-loosening part are each circular plates, and each circular plate may have a diameter corresponding to the head portion of the shovel fixing bolt.

[0019] According to one embodiment, the second fastening prevention part may have a thickness greater than the thickness of the first fastening prevention part.

[0020] According to one embodiment, the second fastening prevention part may have a thickness twice that of the first fastening prevention part.

[0021] According to one embodiment, the first fastening anti-loosening portion may be made of a rubber material having high heat resistance. Here, the rubber material having high heat resistance refers to a heat-resistant rubber material that withstands temperatures of 200°C or higher. For example, it may be made of a material such as fluororubber (Fluoropolymer Elastomer). Here, fluororubber refers to synthetic rubber produced by the polymerization or copolymerization of monomers containing, on average, one or more fluorine atoms among the unit monomers. Fluororubber has excellent heat resistance and chemical resistance, so it can be used as a material for parts of various machinery and equipment.

[0022] According to one embodiment, the fixing part may be a snap ring that is detachably fitted into a circular fitting groove provided at the entrance of a fastening groove into which the shovel fixing bolt is inserted.

[0023] According to a preferred embodiment, the outer diameter of the snap ring may be larger than the diameter of the second fastening anti-loosening part, and the inner diameter of the snap ring may be smaller than the diameter of the second fastening anti-loosening part. Accordingly, when the snap ring is fitted into the fitting groove, the second fastening anti-loosening part, the first fastening anti-loosening part, and the head of the shovel fixing bolt are all constrained in their respective positions by the snap ring, thereby preventing fastening loosening or displacement.

[0024] According to another aspect of the present invention, a vacuum dryer including a shovel fixing device can be provided to prevent the shovel from loosening within the vacuum dryer, thereby preventing internal damage to the vacuum dryer itself and damage to surrounding equipment.

[0025] A vacuum dryer according to one embodiment comprises: a shaft that rotates axially within a drying chamber; a shovel that is connected to the shaft in a radial direction and agitates powder raw materials contained in the drying chamber; and a shovel fixing device that fixes the shovel to the shaft, wherein the shovel fixing device comprises: a shovel fixing bolt that connects the shaft and the shovel; a first fastening loosening prevention part that is in close contact with the shovel fixing bolt and prevents the fastening of the shovel fixing bolt from loosening; a second fastening loosening prevention part that is in close contact with the first fastening loosening prevention part and prevents the fastening of the shovel fixing bolt from loosening; and a fixing part that is fitted into the entrance of a fastening groove into which the shovel fixing bolt is inserted at a set distance from the shovel fixing bolt and supports the second fastening loosening prevention part.

[0026] Specific details of other embodiments are included in the specific details and drawings for carrying out the invention. Effects of the invention

[0027] According to various embodiments of the present invention, one or more of the following effects are present.

[0028] First, it is possible to prevent the shovel fixing bolt connecting the shaft and the shovel inside the vacuum dryer from loosening or detaching. Accordingly, internal damage to the vacuum dryer itself caused by the loosening or detachment of the shovel fixing bolt can be prevented, and damage to surrounding equipment (e.g., Ploughshare Mixer, etc.) can be prevented.

[0029] Second, multiple shovel fixing bolts can be screw-assembled radially between the shaft connecting body and the shovel connecting body inside the vacuum dryer, and then plate members of different materials can be attached to the heads of the shovel fixing bolts to secure them. In addition, by fitting a snap ring into the screw groove opening of the shovel connecting body, the reliability of the structure can be improved to prevent the shovel fixing bolts from loosening or detaching.

[0030] Third, by preventing the loosening or detachment of the shovel fixing bolts connecting the shaft and the shovel inside the vacuum dryer, repair costs can be reduced and production efficiency can be increased. In addition, the maintenance personnel required for equipment fixing measures can be reduced, and the occurrence of magnetic foreign matter can be prevented in advance.

[0031] In addition to the effects described above, the specific effects of the present invention are described together with the specific details for implementing the invention below. Brief explanation of the drawing

[0032] FIG. 1 is a conceptual diagram briefly illustrating the shaft and shovel structure of a vacuum dryer according to one embodiment. FIG. 2 is a conceptual diagram briefly illustrating a shovel fixing device for fixing a shovel to the shaft of a vacuum dryer according to one embodiment. Figure 3 is an enlarged view of the shovel fixing device of a vacuum dryer by enlarging the "3" area of ​​Figure 2. FIG. 4 is a cross-sectional view showing a structure in which a shaft and a shovel are fixed using a shovel fixing device of a vacuum dryer according to one embodiment. FIG. 5 is an exploded perspective view showing the structure before the shaft and the shovel are fixed using a shovel fixing device of a vacuum dryer according to one embodiment. FIG. 6 is a cutaway perspective view showing a structure in which a shaft and a shovel are fixed using a shovel fixing device of a vacuum dryer according to one embodiment. Specific details for implementing the invention

[0033] The advantages and features of the present invention and the methods for achieving them will become clear by referring to the embodiments described below in detail together with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below but may be implemented in various different forms. These embodiments are provided merely to ensure that the disclosure of the present invention is complete and to fully inform those skilled in the art of the scope of the invention, and the present invention is defined only by the scope of the claims. Throughout the specification, the same reference numerals refer to the same components.

[0034] Although terms such as "first," "second," etc., are used to describe various components, it goes without saying that these components are not limited by these terms. These terms are used merely to distinguish one component from another, and unless specifically stated otherwise, the first component may also be the second component.

[0035] Throughout the specification, unless specifically stated otherwise, each component may be singular or plural.

[0036] In the following, the statement that any configuration is placed on the "upper (or lower)" of a component or on the "upper (or lower)" of a component may mean not only that any configuration is placed in contact with the upper (or lower) surface of said component, but also that another configuration may be interposed between said component and any configuration placed on (or below) said component.

[0037] In addition, where it is stated that one component is "connected," "combined," or "connected" to another component, it should be understood that while the components may be directly connected or connected to each other, another component may be "interposed" between each component, or each component may be "connected," "combined," or "connected" through another component.

[0038] Singular expressions used in this specification include plural expressions unless the context clearly indicates otherwise. In this application, terms such as "composed of" or "comprising" should not be interpreted as necessarily including all of the various components or steps described in the specification, and should be interpreted as meaning that some of the components or steps may be omitted or additional components or steps may be included.

[0039] Throughout the specification, "A and / or B" means A, B, or A and B unless specifically stated otherwise, and "C to D" means C or more and D or less unless specifically stated otherwise.

[0040] Hereinafter, a vacuum dryer (1) and a shovel fixing device (100) of a vacuum dryer according to various embodiments will be described in detail with reference to the attached drawings.

[0041] In the drawings, FIG. 1 is a conceptual diagram briefly illustrating the shaft and shovel structure of a vacuum dryer according to one embodiment, and FIG. 2 is a conceptual diagram briefly illustrating a shovel fixing device for fixing a shovel to the shaft of a vacuum dryer according to one embodiment. FIG. 3 is a drawing showing an enlarged view of the shovel fixing device of a vacuum dryer by enlarging the area labeled "3" in FIG. 2. FIG. 4 is a cross-sectional view showing a structure in which the shaft and the shovel are fixed using the shovel fixing device of a vacuum dryer according to one embodiment, FIG. 5 is an exploded perspective view showing the structure before the shaft and the shovel are fixed using the shovel fixing device of a vacuum dryer according to one embodiment, and FIG. 6 is a cutaway perspective view showing a structure in which the shaft and the shovel are fixed using the shovel fixing device of a vacuum dryer according to one embodiment.

[0042] Referring to FIGS. 1 and 2, the connection structure of the shaft (10) and the shovel (20) of a vacuum dryer (1) according to one embodiment is briefly shown.

[0043] A vacuum dryer (1) according to one embodiment includes a shaft (10) that is axially arranged and rotates inside a drying chamber (not shown). A shovel (20) may be connected to the radial direction of the shaft (10).

[0044] The shovel (20) rotates by the shaft (10) and is a device for mixing powder raw materials contained inside a drying chamber (not shown).

[0045] The shovel (20) is connected radially through the outer diameter of the shaft (10) and can be securely fastened to the shaft (10) using a separate shovel fixing device (100) (see FIG. 2).

[0046] If the shovel (20) fixed to the shaft (10) inside the vacuum dryer (1) is released, the interior of the vacuum dryer (1) may be damaged, or there may be a risk of damaging surrounding equipment (e.g., Ploughshare Mixer, etc.).

[0047] According to one embodiment, the shaft (10) may include a shaft connecting body (11) that extends radially from the outer diameter of the shaft (10).

[0048] According to one embodiment, the shovel (20) may include a shovel body (22) that rotates inside a drying chamber and agitates powder raw materials, and a shovel connecting body (21) whose one end is connected to the shovel body (22) and whose other end is fastened and fixed to a shaft connecting body (11) (see FIG. 2).

[0049] According to one embodiment, the shovel fixing device (100) of a vacuum dryer can be fixed by connecting the shaft connecting body (11) and the shovel connecting body (21).

[0050] Hereinafter, with reference to FIGS. 3 to 6, a shovel fixing device (100) of a vacuum dryer (1) according to various embodiments will be described in detail.

[0051] A shovel fixing device (100) of a vacuum dryer (1) according to one embodiment may include a shovel fixing bolt (110), a first fastening anti-loosening part (120), a second fastening anti-loosening part (130), and a fixing part (140).

[0052] According to one embodiment, the shovel fixing bolt (110) refers to a bolt that fastens the shaft (10) and the shovel (20). More specifically, the shovel fixing bolt (110) can fasten and fix the shaft connecting body (11) and the shovel connecting body (21) (see FIG. 4 and FIG. 6).

[0053] According to one embodiment, the first fastening anti-loosening part (120) is in close contact with the shovel fixing bolt (110) and can prevent the fastening of the shovel fixing bolt (110) that fastens the shaft connecting body (11) and the shovel connecting body (21) from loosening. More specifically, the first fastening anti-loosening part (120) can be in contact with the head part (111) of the shovel fixing bolt (110) and elastically support the shovel fixing bolt (110) so that it does not loosen (see FIG. 4 and FIG. 6).

[0054] According to one embodiment, the second fastening anti-loosening part (130) is in close contact with the first fastening anti-loosening part (120) and can support the first fastening anti-loosening part (120), which elastically supports the shovel fixing bolt (110), even more strongly from the outside. Accordingly, the fastening anti-loosening effect of the shovel fixing bolt (110) can be improved (see FIG. 4 and FIG. 6).

[0055] According to one embodiment, the fixing part (140) can be fitted in a ring shape into the entrance (28) of the fastening groove into which the shovel fixing bolt (110) is inserted, at a set distance from the fastening direction with respect to the shovel fixing bolt (110). Accordingly, the fixing part (140) prevents the second fastening loosening prevention part (130) and the first fastening loosening prevention part (120) from coming loose, and consequently prevents the shovel fixing bolt (110) from coming loose and coming loose (see FIG. 4 and FIG. 6).

[0056] According to a preferred embodiment, the shovel fixing device (100) can fasten three shovel fixing bolts (110) in series at three locations between the shovel connecting body (21) and the shaft connecting body (11). In this way, by having a structure in which three shovel fixing bolts (110) are fastened in series, the shovel connecting body (21) and the shaft connecting body (11) can maintain a state of being firmly connected and fixed with a strong fastening force (see FIG. 3).

[0057] More specifically, as illustrated in FIG. 4, the shovel fixing device (100) may include three shovel fixing bolts (110) that are connected in series at spaced apart from each other at a set interval in the shovel connecting body (21). Additionally, it may include three first fastening anti-loosening parts (120) that support each of the three shovel fixing bolts (110), three second fastening anti-loosening parts (130), and three fixing parts (140). However, it is not necessarily limited to three numbers and may be applied by changing the number to two, four, or more.

[0058] According to one embodiment, the shovel fixing bolt (110) may include a head portion (111) that is received in the entrance (28) of the fastening groove and has one side (i.e., the outer side) in close contact with the first fastening anti-loosening portion (120). Additionally, the shovel fixing bolt (110) may further include a body portion (112) that extends by a set length from the other side (i.e., the inner side) of the head portion (111) and is inserted through the shovel connecting body (21). Additionally, the shovel fixing bolt (110) may include a screw portion (113) that is connected to the end of the body portion (112) and is screw-fastened to the shaft connecting body (11) (see FIGS. 4 to 6).

[0059] According to one embodiment, the first fastening anti-loosening part (120) may be a circular plate made of an elastic material (see FIG. 3, FIG. 5, FIG. 6). One side of the first fastening anti-loosening part (120), provided as a circular plate made of an elastic material, may be in close contact with the head part (111) of the shovel fixing bolt (110).

[0060] According to one embodiment, the second fastening prevention part (130) may be a circular plate made of an elastic material (see FIG. 3, FIG. 5, FIG. 6). The second fastening prevention part (130) may have one side (i.e., the inner side) in close contact with the other side (i.e., the outer side) of the first fastening prevention part (120), and at the same time, the fixing part (140) may support the other side (i.e., the outer side) to constrain the position.

[0061] According to one embodiment, the first fastening prevention part (120) and the second fastening prevention part (130) may each have a circular plate shape with different thicknesses and the same diameter (see FIG. 5).

[0062] Each circular plate provided as the first fastening anti-loosening part (120) and the second fastening anti-loosening part (130) may have a diameter corresponding to the head part (111) of the shovel fixing bolt (110).

[0063] Preferably, the diameter of the circular plate provided as the first fastening anti-loosening part (120) and the second fastening anti-loosening part (130) is equal to or larger than the diameter of the head part (111) of the shovel fixing bolt (110). Accordingly, the contact surface between the first fastening anti-loosening part (120), the second fastening anti-loosening part (130), and the head part (111) of the shovel fixing bolt (110) is increased, thereby providing a stable contact support structure.

[0064] According to one embodiment, the second fastening prevention part (130) may have a thickness greater than the thickness of the first fastening prevention part (120) (see FIG. 4 and FIG. 5).

[0065] According to a preferred embodiment, the thickness of the second fastening prevention part (130) is preferably twice the thickness of the first fastening prevention part (120). For example, if the thickness of the circular plate of elastic material forming the first fastening prevention part (120) is 1t, the thickness of the circular plate of rigid material forming the second fastening prevention part (130) may be 2t.

[0066] The first fastening anti-loosening part (120) can be in close contact with the head part (111) of the shovel fixing bolt (110) and can serve to support it using elasticity. Additionally, the second fastening anti-loosening part (130) is placed over the first fastening anti-loosening part (120) so that it can prevent the fastening and detachment of the shovel fixing bolt (110) by utilizing thick rigidity.

[0067] According to one embodiment, the first fastening anti-loosening part (120) may be made of a rubber material having high heat resistance. Here, the rubber material having high heat resistance refers to a heat-resistant rubber material that withstands temperatures of 200°C or higher. For example, it may be made of a material such as fluororubber (Fluoropolymer Elastomer).

[0068] Here, the term "fluororubber material" may refer to a material commonly used by product names such as VITON. Fluororubber refers to synthetic rubber produced by the polymerization or copolymerization of monomers containing, on average, one or more fluorine atoms among the unit monomers. Fluororubber has excellent heat resistance and chemical resistance, so it can be used as a material for parts of various machinery and equipment.

[0069] According to one embodiment, the fixing part (140) may be a snap ring that can be detachably coupled to a circular fitting groove (29) provided in the entrance (29) of the fastening groove into which the shovel fixing bolt (110) is inserted.

[0070] According to a preferred embodiment, the outer diameter of the snap ring, i.e., the fixing part (140), may be larger than the diameter (i.e., outer diameter) of the second fastening anti-loosening part (130), and the inner diameter of the fixing part (140) may be formed to be smaller than the diameter (i.e., outer diameter) of the second fastening anti-loosening part (130) (see FIG. 4).

[0071] Accordingly, when the snap ring, i.e., the fixing part (140), is mounted in the fitting groove (29), the second fastening anti-loosening part (130) may be caught on the fixing part (140) and not detach to the outside. As a result, the second fastening anti-loosening part (130), the first fastening anti-loosening part (120), and the head part (111) of the shovel fixing bolt (110) are all bound in position by the snap ring, i.e., the fixing part (140), mounted in the fitting groove (29), and fastening loosening or detachment can be prevented.

[0072] As described above, according to various embodiments of the present invention, loosening and detachment of the shovel fixing bolt connecting the shaft and the shovel within the vacuum dryer can be prevented. Accordingly, there is an advantageous technical effect of preventing internal damage to the vacuum dryer itself due to loosening and detachment of the shovel fixing bolt, and preventing damage to surrounding equipment (e.g., Ploughshare Mixer, etc.).

[0073] Specifically, multiple shovel fixing bolts can be screw-assembled radially between a shaft connecting body and a shovel connecting body inside a vacuum dryer, and then plate members of different materials can be attached to the heads of the shovel fixing bolts to secure them. In addition, by fitting a snap ring into the screw groove opening of the shovel connecting body, the reliability of the structure can be improved to prevent the shovel fixing bolts from loosening or detaching.

[0074] Furthermore, according to various embodiments of the present invention, by preventing the loosening and detachment of the shovel fixing bolt connecting the shaft and the shovel within the vacuum dryer, repair costs can be reduced and production efficiency can be increased. In addition, there are advantages such as reducing the maintenance personnel required for equipment fixing measures and preventing the occurrence of magnetic foreign matter in advance.

[0075] Although the present invention has been described above with reference to the illustrated drawings, the present invention is not limited by the embodiments and drawings disclosed in this specification, and it is obvious that various modifications can be made by a person skilled in the art within the scope of the technical concept of the present invention. Furthermore, even if the effects of the configuration according to the present invention were not explicitly described while describing the embodiments of the present invention above, it is natural to acknowledge that the effects predictable by said configuration should also be recognized. Explanation of the symbols

[0076] 1: Vacuum dryer 10: Shaft 11: Shaft connecting body 20: Shovel 21: Shovel connecting body 22: Shovel Body 28: Entrance of the fastening groove 29: Insertion groove 100: Shovel fixing device 110: Shovel fixing bolt 111: Head section 112: Body 113: Screw part 120: First fastening anti-loosening part (or circular plate made of elastic material) 130: Second fastening anti-loosening part (or circular plate made of rigid material) 140: Fixing part (or snap ring)

Claims

Claim 1 A shovel fixing device for a vacuum dryer comprising: a shaft arranged axially and rotating inside a drying chamber; and a shovel connected to the shaft so as to be connected radially to the shaft and stirring powder raw material contained in the drying chamber; a shovel fixing bolt connecting the shaft and the shovel; a first fastening loosening prevention part in close contact with the shovel fixing bolt and preventing the fastening of the shovel fixing bolt from loosening; and a second fastening loosening prevention part in close contact with the first fastening loosening prevention part and preventing the fastening of the shovel fixing bolt from loosening. A shovel fixing device for a vacuum dryer, comprising: a fixing part that is fitted into the entrance of a fastening groove into which the shovel fixing bolt is inserted and supports the second fastening anti-loosening part; wherein the first fastening anti-loosening part is a plate of an elastic material that has one surface in close contact with the head portion of the shovel fixing bolt and supports the shovel fixing bolt, and the second fastening anti-loosening part is a plate of a rigid material that has one surface in close contact with the other surface of the first fastening anti-loosening part and whose position is constrained by the fixing part supporting the other surface. Claim 2 A shovel fixing device for a vacuum dryer according to claim 1, wherein the shaft comprises a shaft connecting body extending radially from the outer diameter of the shaft; and the shovel comprises a shovel body for stirring powder raw materials; and a shovel connecting body having one end connected to the shovel body and the other end connected to the shaft connecting body. Claim 3 In paragraph 2, the shovel fixing bolt comprises: a head portion that is in close contact with the first fastening anti-loosening portion; a body portion that extends from the head portion and is inserted through the shovel connecting body; and a screw portion that is connected to the end of the body portion and is screw-fastened to the shaft connecting body; a shovel fixing device for a vacuum dryer. Claim 4 delete Claim 5 A shovel fixing device for a vacuum dryer, wherein, in claim 1, each of the first fastening anti-loosening part and the second fastening anti-loosening part is a circular plate, and the circular plate has a diameter equal to or greater than the diameter of the head part of the shovel fixing bolt. Claim 6 In claim 1, the second fastening anti-loosening part has a thickness greater than that of the first fastening anti-loosening part, a shovel fixing device for a vacuum dryer. Claim 7 In claim 1, the first fastening anti-loosening part is made of a rubber material having high heat resistance, a shovel fixing device for a vacuum dryer. Claim 8 A shovel fixing device for a vacuum dryer, wherein the fixing part is a snap ring detachably fitted into a fitting groove provided at the entrance of a fastening groove into which the shovel fixing bolt is inserted. Claim 9 A shaft arranged axially and rotating inside a drying chamber; a shovel connected to the shaft so as to be connected radially to the shaft and stirring powder raw materials contained in the drying chamber; and a shovel fixing device for fixing the shovel to the shaft; wherein the shovel fixing device comprises: a shovel fixing bolt connecting the shaft and the shovel; a first fastening loosening prevention part in close contact with the shovel fixing bolt and preventing the fastening of the shovel fixing bolt from loosening; and a second fastening loosening prevention part in close contact with the first fastening loosening prevention part and preventing the fastening of the shovel fixing bolt from loosening. A vacuum dryer comprising: a fixing part that is fitted into the entrance of a fastening groove into which the shovel fixing bolt is inserted and supports the second fastening anti-loosening part; wherein the first fastening anti-loosening part is a plate of an elastic material that has one surface in close contact with the head portion of the shovel fixing bolt and supports the shovel fixing bolt, and the second fastening anti-loosening part is a plate of a rigid material that has one surface in close contact with the other surface of the first fastening anti-loosening part and the fixing part supports the other surface to constrain the position.

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