Anti-corrosion fastener and submersible pump

Abstract

The application discloses an anti-corrosion fastener and a submersible pump, and belongs to the technical field of the submersible pump. The fastener comprises a screw rod assembly and a nut assembly. The screw rod assembly comprises a screw rod and a protective layer. The screw rod is provided with a threaded part and a coating part. The protective layer is wrapped on the coating part. The nut assembly comprises a nut which is threadedly connected with the threaded part and a protective sleeve which contains the nut. The threaded part is contained in the protective sleeve after being connected with the nut. The fastener has high overall structural strength and good anti-corrosion performance, thereby reducing the overall cost of the submersible pump. The sealing gasket with the protruding part can keep sealing in the axial and radial directions, prevent the screw rod and the nut from being corroded, and has a long service life. The nut is provided with a stress ring, thereby effectively improving the strength of the nut assembly and indirectly improving the assembly efficiency.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of submersible pumps, and particularly relates to a corrosion-resistant fastener and a submersible pump. BACKGROUND

[0002] Fasteners are a kind of mechanical parts widely used for fastening connection, and usually include bolts, studs, screws, nuts and the like. Corrosion-resistant fasteners are more commonly used in industrial environments. For example, in submersible pumps for conveying corrosive liquids, bolts and nuts are usually used as fasteners.

[0003] A submersible pump is a vertical pump with an impeller and a pump body immersed in the material to be conveyed and connected to a motor shaft. Submersible pumps are made according to the different lengths needed to extend into the container. The parts of a submersible pump that come into contact with the material are generally selected according to the requirements of the material, with metal and non-metal materials. The cantilever submersible pump made of ultra-high molecular weight polyethylene and polypropylene as the main material has excellent wear resistance and corrosion resistance. Bolts and nuts are usually used as fasteners to connect the pump shell that is immersed in corrosive media for a long time. The bolts and nuts used as fasteners usually have several materials, 1 is corrosion-resistant plastic material, 2 is ordinary steel material, and 3 is stainless steel material. These fasteners have some problems, 1, the bolt and nut made of corrosion-resistant plastic material as a fastener have insufficient structural strength; 2, the bolt and nut made of ordinary steel material are not corrosion-resistant; 3, the bolt and nut made of stainless steel material have enhanced corrosion resistance, but in order to adapt to various corrosive liquids, corrosion-resistant stainless steel fasteners are needed, resulting in high cost, and the stainless steel material will be gradually corroded and damaged after long-term use, which requires regular replacement, further increasing the use and maintenance cost of customers. SUMMARY

[0004] Technical problem: In view of the above problems in the prior art, the technical problem to be solved by the present application is to provide a corrosion-resistant fastener and a submersible pump that can be used in corrosive places and reduce the use cost.

[0005] Technical solution: In order to solve the above technical problems, the technical solution adopted by the present application is as follows:

[0006] A corrosion-resistant fastener for fastening connection of a fastened part, comprising a screw rod assembly and a nut assembly, the screw rod assembly comprising a screw rod and a protective layer, the screw rod being provided with a threaded portion and a cladding portion, and the protective layer being wrapped on the cladding portion, the nut assembly comprising a nut threadedly connected with the threaded portion and a protective sleeve accommodating the nut, and the threaded portion being accommodated in the protective sleeve after being connected with the nut.

[0007] Preferably, a sealing gasket is further sleeved on the screw rod assembly, and the nut assembly is moved towards the fastened part to press the sealing gasket against the fastened part.

[0008] Preferably, the sealing gasket is provided with a protruding part, the protective sleeve is provided with a corresponding recess part corresponding to the protruding part, and the nut assembly compresses the protruding part on the protective layer after compressing the sealing gasket.

[0009] Preferably, the protruding part is in the shape of a circular truncated cone, and the side surface of the protruding part is a stress surface.

[0010] Preferably, the nut is provided with a stress ring, and the nut compresses the protective sleeve and the sealing gasket on the fastener through the stress ring.

[0011] Preferably, the thickness of the protective layer is greater than or equal to 0.1 mm.

[0012] Preferably, the protective layer is a corrosion-resistant sleeve made of plastic, and the corrosion-resistant sleeve is fixed on the coating part by injection molding, the protective sleeve is made of plastic and is fixed on the nut by injection molding.

[0013] Preferably, the screw rod is a double-end stud, the threaded part is arranged at both ends of the screw rod, and the number of the nut assemblies is two.

[0014] Preferably, the screw rod is a bolt, the threaded part is arranged at one end of the screw rod, and the coating part includes a head part and a rod body part.

[0015] The application also provides a submersible pump, which comprises a motor, a main shaft, an impeller and an impeller shell, and further comprises a fastener for connecting and fastening the impeller shell, and the fastener is any of the above-described anti-corrosion fasteners.

[0016] Advantages: compared with the prior art, the present application has the following advantages: 1, by setting the plastic coated screw and nut, cooperate as fastener, screw and nut are made of ordinary steel, protective layer and protective sleeve are made of corrosion-resistant plastic, injection molding process wraps screw and nut, fastener overall structural strength is high, good corrosion resistance, instead of existing stainless steel bolt and nut, reduce more than 70% cost, reduce the overall cost of submersible pump; 2, the protective layer and protective sleeve are made of polyethylene plastic material injection molding, good corrosion resistance, low cost, connected with screw nut, suitable for long-term use in corrosive medium, long service life, improve the overall service life of submersible pump; 3, the sealing gasket with protruding part is set, which can keep sealing in axial and radial directions, not only can block the corrosive medium from entering the fastener inside through the gap, but also can block the corrosive medium from entering the fastener inside through the gap between the screw and the protective sleeve, prevent the screw and nut from being corroded, long service life; 4, the nut is provided with a stress ring, the sealing gasket is pressed through the stress ring, the sealing effect is improved, at the same time, the stress ring bears the reaction force of the fastened part, blocks the nut from moving downward too much, prevents the protective layer from being damaged, also blocks the screw from damaging the protective sleeve upward, effectively improves the strength of the nut assembly, indirectly improves the assembly efficiency. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 is a part of the cross-sectional structure of the embodiment 1 of the present application;

[0018] Figure 2 is a screw structure diagram of the embodiment 1 of the present application;

[0019] Figure 3 is a first embodiment structure diagram of the nut assembly of the embodiment 1 of the present application;

[0020] Figure 4 is a sealing gasket structure diagram of the embodiment 1 of the present application;

[0021] Figure 5 is a second embodiment structure diagram of the nut assembly of the embodiment 1 of the present application;

[0022] Figure 6 is a cross-sectional structure diagram of the embodiment 1 of the present application in use state;

[0023] Figure 7 is a cross-sectional structure diagram of the embodiment 2 of the present application;

[0024] Figure 8 is a screw structure diagram of the embodiment 2 of the present application;

[0025] Figure 9 is a whole structure diagram of the submersible pump of the present application. DETAILED DESCRIPTION

[0026] The present application will be further illustrated in conjunction with specific examples, which are implemented on the premise of the technical solutions of the present application, and it should be understood that these examples are only used to illustrate the present application and not to limit the scope of the present application.

[0027] Example 1

[0028] As shown in Figure 1 , Figure 2 , Figure 3 and Figure 4 , an anti-corrosion fastener for fastening a fastened object comprises a screw rod assembly 1, a nut assembly 2 and a sealing gasket 3, the screw rod assembly 1 and the nut assembly 2 are threadedly connected to cooperatively fasten the fastened object.

[0029] As shown in Figure 1 and Figure 2 , the screw rod assembly 1 comprises a screw rod 11 and a protective layer 12, the screw rod 11 is in the shape of a cylindrical rod, made of metal material such as 45# steel, with threaded portions 111 at both ends and a cladding portion 112 in the middle section, and the protective layer 12 is a corrosion-resistant sleeve made of plastic material such as polyethylene or polypropylene, which is fixed on the cladding portion 112 by injection molding, i.e. the screw rod 11 is placed in a mold, and the plastic material such as polyethylene is melted and then attached to the cladding portion 112 after processes of pressurization, injection, cooling and separation, the surface of the cladding portion 112 is roughened to increase adhesion, the thickness of the protective layer 12 is 1mm (the thickness can be set according to needs), and the diameter of the cladding portion 112 is 2mm smaller than that of the threaded portions 111, so that the overall diameter of the cladding portion 112 with the corrosion-resistant sleeve is equal to that of the threaded portions 111, and thus the screw rod 11 is in the shape of a cylindrical rod with the same diameter from top to bottom.

[0030] As shown in Figure 1 and Figure 3 , the nut assembly 2 comprises a nut 21 threadedly connected with the threaded portions 111 and a protective sleeve 22 accommodating the nut 21, the protective sleeve 22 has a cavity formed therein, the threaded portions 111 enter the cavity of the protective sleeve 22 after being connected with the nut 21, the nut 21 is made of the same metal material as the screw rod 11, and the protective sleeve 22 is made of plastic material such as polyethylene or polypropylene, which is connected with the nut 21 by injection molding, i.e. the nut 21 is placed in a mold, and the plastic material such as polyethylene is melted and then attached to the nut 21 after processes of pressurization, injection, cooling and separation, the protective sleeve 22 is hexagonal in shape, which is the same as the conventional nut, facilitating rotation, and the nut 21 has a recess in the middle section, which facilitates more stable connection with the protective sleeve 22 after injection molding.

[0031] As Figure 1 and Figure 4 shown, the sealing gasket 3 is sleeved on the screw rod 11, and the sealing gasket 3 is made of corrosion-resistant rubber material. When the nut assembly 2 is tightened, the nut assembly 2 moves towards the fastened part, so as to press the sealing gasket 3 against the fastened part, thereby completing the radial sealing of the screw rod 11, preventing external liquid and other media from entering the nut assembly 2 from the gap between the protective sleeve 22 and the fastened part, and causing corrosion to the screw rod 11 and the nut 21. The sealing gasket 3 is annular as a whole, and a protruding portion 31 is arranged in the middle. The protruding portion 31 is in the shape of a circular truncated cone, and the edge of the cavity of the protective sleeve 22 is chamfered, thereby forming a recess 221 corresponding to the protruding portion 31. After the nut assembly 2 presses the sealing gasket 3, the side surface of the protruding portion 31 in the shape of a circular truncated cone serves as a stress surface, and the chamfering of the protective sleeve 22 presses the protruding portion 31 against the protective layer 12, thereby achieving axial sealing of the screw rod 11, preventing the corrosive liquid medium in the fastened part from entering the nut assembly 2 from the gap between the screw rod 11 and the fastened part and between the screw rod 11 and the protective sleeve 22, and protecting the screw rod 11 and the nut 21 made of metal.

[0032] As Figure 5 shown, the nut assembly 2 is different from the first embodiment in that a stress ring 211 is arranged on the nut 21, and the stress ring 211 is connected to the nut 21 by welding. The nut 21 presses the protective sleeve 22 and the sealing gasket 3 against the fastened part through the stress ring 211. During the tightening of the nut assembly 2, the nut assembly 2 continuously applies pressure to the fastened part. The nut assembly 2 of the first embodiment does not bear the reaction force and is far away from the fastened part, and the protective sleeve 22 directly bears the reaction force. As the nut assembly 2 is continuously tightened, the nut 21 continuously moves downwards and easily moves beyond the thread portion 111 towards the protective layer 12 on the cover layer portion 112 after being tightened excessively, the internal thread of the nut 21 can damage the protective layer 12, and the screw rod 11 can break through the protective sleeve 22 upwards, thereby damaging the entire corrosion-resistant fastener. Therefore, manual slow tightening is generally adopted during assembly. The nut assembly 2 with the stress ring 211 can bear the reaction force of the fastened part through the sealing gasket 3 and the protective sleeve 22, so that the nut 21 made of metal bears the reaction force. Under the blockage of the stress ring 211, the nut 21 cannot continue to move downwards, the protective layer 12 cannot be damaged, the screw rod 11 cannot move upwards, and the protective sleeve 22 cannot be broken. The arrangement of the stress ring 211 can ensure that the nut assembly 2 will not be damaged even if it bears a large tightening force, and the nut assembly 2 can be directly tightened by using a pneumatic wrench or the like, thereby effectively improving the assembly efficiency.

[0033] As Figure 6As shown, the screw 11 in this embodiment 1 is a double-ended stud with threaded portions 111 at both ends. In use, after the screw assembly 1 passes through the fastener, a sealing gasket 3 is put on each end, and then the two nut assemblies 2 are tightened to complete the fastening connection between multiple fasteners.

[0034] like Figure 9 As shown, a submersible pump includes a motor 6, a main shaft 7, an impeller 8, and an impeller housing 9. The impeller 8 rotates under the drive of the motor 6 to transport the medium. The impeller housing 9 is divided into multiple parts and is arranged around the impeller 8. The multiple parts of the impeller housing 9 are fastened together by anti-corrosion fasteners. Neither the external corrosiveness nor the corrosive medium transported internally can corrode the screw nut. The overall anti-corrosion effect is good, the impeller housing 9 has a stable connection and good sealing effect, and the submersible pump has a long service life.

[0035] Example 2

[0036] like Figure 7 and Figure 8 As shown, the difference from Embodiment 1 is that the screw 11 is a bolt, the threaded part 111 is provided at one end of the screw 11, the covering part 112 includes a head 1121 and a rod part 1122, and the protective layer 12 is wrapped around the head 1121 and the rod part 1122; the nut 21 and the force-bearing ring 211 of the nut assembly 2 are integrally formed, and the nut 21 no longer has a groove. The outer ring of the force-bearing ring 211 is directly equal to the diameter of the sealing gasket 3. The force-bearing ring 211 has a larger ring width, thereby obtaining a larger force-bearing area and increasing the overall strength and sealing effect of the nut assembly 2. In this embodiment, the anti-corrosion fastener is used by passing through multiple through holes on the fastener from one end of the threaded part 111 (a conventional corrosion-resistant rubber gasket can also be fitted on the rod body at one end of the head 1121 of the screw 11 to stabilize the head 1121 and the fastener), and then a sealing gasket 3 is fitted on one end of the threaded part 111. The nut assembly 2 is then threadedly connected to the threaded part 111 and tightened to complete the fastening connection between multiple fasteners.

[0037] The fasteners of this invention use ordinary steel such as 45# steel for the screw and nut. Compared with the stainless steel bolts and nuts used in the past, the strength is improved and the cost is significantly reduced (the price of stainless steel is more than 3 times that of 45# steel per ton, and the cost of a single bolt and nut can be reduced by 70%). Fasteners are widely used in industrial devices such as cantilever submersible pumps that need to operate in corrosive media. Replacing all of them with the fasteners of this invention can reduce the overall cost, improve competitiveness and profits.

[0038] The above are merely preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. An anticorrosive fastener for fastening a fastened member, characterized by, The anti-corrosion fastener comprises a screw rod assembly (1), a nut assembly (2) and a sealing gasket (3) sleeved on the screw rod assembly (1), the screw rod assembly (1) comprises a screw rod (11) and a protective layer (12), the screw rod (11) is provided with a threaded part (111) and a cladding part (112), the protective layer (12) is wrapped on the cladding part (112), the nut assembly (2) comprises a nut (21) threadedly connected with the threaded part (111) and a protective sleeve (22) containing the nut (21), the threaded part (111) is contained in the protective sleeve (22) after being connected with the nut (21), the nut assembly (2) is moved towards a fastened part to press the sealing gasket (3) against the fastened part, so that the radial sealing of the screw rod (11) is completed, the sealing gasket (3) is provided with a protruding part (31), the protective sleeve (22) is provided with a recessed part (221) corresponding to the protruding part (31), the protruding part (31) is pressed against the protective layer (12) after the nut assembly (2) presses the sealing gasket (3), the protective layer (12) is a corrosion-resistant sleeve made of plastic, the corrosion-resistant sleeve is fixed on the cladding part (112) by injection molding, the protective sleeve (22) is made of plastic and is fixed on the nut (21) by injection molding, the nut (21) is provided with a force ring (211), the protective sleeve (22) and the sealing gasket (3) are pressed against the fastened part by the nut (21) through the force ring (211), the reaction force of the fastened part acts on the force ring (211) through the sealing gasket (3) and the protective sleeve (22), so that the nut (21) bears the reaction force.

2. The corrosion resistant fastener of claim 1, wherein, The protruding part (31) is in the shape of a circular truncated cone, and the side surface of the protruding part (31) in the shape of a circular truncated cone is a force surface.

3. The corrosion-resistant fastener of claim 1, wherein, The thickness of the protective layer (12) is greater than or equal to 0.1 mm.

4. The corrosion resistant fastener of claim 1, wherein, The screw rod (11) is a double-end stud, the threaded part (111) is arranged at two ends of the screw rod (11), and the number of the nut assemblies (2) is two.

5. The corrosion-resistant fastener of claim 1, wherein, The screw rod (11) is a bolt, the threaded part (111) is arranged at one end of the screw rod (11), and the cladding part (112) comprises a head part (1121) and a rod body part (1122).

6. A submersible pump comprising an electric motor (6), a main shaft (7), an impeller (8) and an impeller housing (9), characterized in that The anti-corrosion fastener further comprises a fastened part for connecting and fastening the impeller shell (9), and the fastened part is the anti-corrosion fastener according to any one of claims 1-5.

Images