Corrosion-resistant joint structure

Abstract

The utility model belongs to the technical field of instrument joint structures, and discloses a corrosion-resistant joint structure. The device comprises a nut and a plug connector, the plug connector is plugged in the instrument, a first thread is formed on one side, far away from the instrument, of the plug connector, the nut is screwed in the first thread, and the potential of the nut and the potential of the material of the plug connector are similar or the same. The problem that in the prior art, a connector on a gas meter is frequently corroded, and large economic losses are caused to a meter factory is solved.

Description

TECHNICAL FIELD

[0001] The utility model relates to instrument joint structure technical field especially relates to a kind of corrosion-resistant joint structure. BACKGROUND

[0002] As the key equipment of measuring gas usage, gas meter has experienced the evolution from diaphragm gas meter to intelligent gas meter. With the popularization of urban gas pipeline network, the installation environment of gas meter is increasingly complex, and outdoor installation becomes the norm. In order to ensure the normal operation and service life of the gas meter, its corrosion resistance becomes more and more important.

[0003] At present, the common gas meter inlet and outlet joint on the market, its main part (connecting part with gas pipeline) usually adopts carbon steel galvanized material to ensure strength and durability, and reduce cost. However, in order to process conveniently and prevent rust, some manufacturers will use copper material or stainless steel material. However, when the gas meter is used in long-term complex environment, the carbon steel galvanized material directly contacts with copper material or stainless steel material, and under the action of electrolyte (such as rainwater, humid air), galvanic corrosion is easily formed. If corrosion problem occurs, it needs to be returned to the factory for repair and replacement of new meter, which will cause great economic loss to the gas meter factory. SUMMARY

[0004] The utility model aims at providing a kind of corrosion-resistant joint structure, solve the joint on the gas meter in prior art and often appear corrosion, cause great economic loss to the problem of meter factory.

[0005] In order to achieve this purpose, the utility model adopts the following technical scheme: the utility model provides a kind of corrosion-resistant joint structure, including nut and plug-in part, the plug-in part is plugged in instrument, the side of the plug-in part away from the instrument is formed with first screw thread, the nut is screwed in the first screw thread, the potential of the material of the nut and the plug-in part is similar or same.

[0006] As preferred, the material of the nut is carbon steel, and the material of the plug-in part is carbon steel.

[0007] As preferred, the surface of the nut is electroplated with a first coating layer, and the material of the first coating layer is zinc or zinc-aluminum-magnesium or ceramic or non-metallic material.

[0008] As preferred, the surface of the plug-in part is electroplated with a second coating layer, and the material of the second coating layer is zinc or zinc-aluminum-magnesium or ceramic or non-metallic material.

[0009] As preferably, the side of the plug-in part close to the instrument is formed with a plug-in end, the instrument is formed with a plug-in hole, the plug-in end is interference fit with the plug-in hole, the inner wall of the plug-in hole is electroplated with a third coating, and the third coating is zinc or zinc-aluminum-magnesium or ceramic or non-metal material.

[0010] As preferably, the side of the plug-in part close to the instrument is formed with a second thread, the instrument is formed with a threaded hole, the plug-in part is threaded with the instrument, the inner wall of the threaded hole is electroplated with a fourth coating, and the fourth coating is zinc or zinc-aluminum-magnesium or ceramic or non-metal material.

[0011] As preferably, the first gasket is made of nylon material.

[0012] As preferably, the second gasket is made of nylon material.

[0013] As preferably, the surface of the nut and the plug-in part is sprayed with epoxy resin.

[0014] Beneficial effects: by using the materials with similar potential or the same material for the nut and the plug-in part, the dissimilar metal contact is converted into the same metal system, the driving potential of electrochemical corrosion is fundamentally eliminated, the phenomenon of electrochemical corrosion can be reduced, the service life of the joint structure is prolonged, and the subsequent maintenance cost is reduced. BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1 is a sectional view of the corrosion-resistant joint structure.

[0016] In the figure: 1, nut; 2, plug-in part; 21, second thread. DETAILED DESCRIPTION

[0017] The utility model will be further described in detail below in combination with the drawings and examples. It can be understood that the specific examples described here are only used to explain the utility model, and not limited to the utility model. In addition, it should be noted that in order to facilitate the description, only the part related to the utility model is shown in the drawings, not all the structures.

[0018] In the description of the utility model, unless another definite provision and limitation, the term "connect", "connection", "fixed" should be broad sense understanding, for example, can be fixed connection, also can be detachable connection, or be integrated;Can be mechanical connection, also can be electrical connection;Can be directly connected, also can be indirectly connected through the intermediate medium, can be two elements inside the communication or two element's mutual action relation.For the ordinary skill in the art, the above-mentioned terms can be understood according to the specific meaning of the utility model.

[0019] In the utility model, unless another definite provision and limitation, the first feature is "on" or "under" the second feature can include the first and second features direct contact, also can include the first and second features are not direct contact but contact through the additional feature between them.Moreover, the first feature is "on", "above" and "on" the second feature includes the first feature is directly above and obliquely above the second feature, or just indicates that the first feature horizontal height is higher than the second feature.The first feature is "under", "below" and "under" the second feature includes the first feature is directly below and obliquely below the second feature, or just indicates that the first feature horizontal height is less than the second feature.

[0020] In the description of the embodiment, the terms "on", "under", "right", etc. Orientation or position relationship is based on the orientation or position relationship shown in the drawing, only for the convenience of description and simplification operation, and does not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, therefore cannot be understood as a limitation on the utility model.In addition, the terms "first", "second" are only used to distinguish in the description, and have no special meaning.

[0021] Under the prior art, after the most nut instrument on the plug-in piece is matched, galvanic corrosion is easily formed, which causes corrosion phenomenon at the joint.

[0022] In order to solve the above problems, as Figure 1 The utility model provides a kind of corrosion-resistant joint structure, including nut 1 and plug-in piece 2, plug-in piece 2 is inserted in instrument, first thread is formed on the side of plug-in piece away from instrument, nut 1 is screwed in first thread, the potential of the material of nut 1 and plug-in piece 2 is similar or same.

[0023] The utility model discloses a chemical test through different materials effectively solves the galvanic corrosion problem when copper and steel parts cooperate, and in the joint structure of copper steel connection under the prior art, there is 780mV potential difference between copper (standard electrode potential +0.34V) and steel (-0.44V), and strong galvanic current can be formed in the humid environment, leading to the annual corrosion rate of steel parts is as high as 0.1-0.3mm. The utility model adopts the nut 1 and the plug-in part 2 combination of the potential similar or same material, and the contact of dissimilar metal is converted into the same kind / kind metal system, and the driving potential of electrochemical corrosion is fundamentally eliminated. When the potential difference of both materials is less than or equal to 50mV, the galvanic corrosion rate can be reduced by more than 95%. In the salt spray environment of 5% NaCl concentration, after standing test for 500 hours, the overall structure rusting grade is less than or equal to Ri 1 (rust area is less than or equal to 0.05%), compared with the service life of the traditional copper steel connection structure is prolonged. At the same time, the direct plug-in cooperation of plug-in part 2 and instrument is supplemented by the thread locking structure, the installation precision is guaranteed, and double mechanical seals are formed, and the interface electrolyte permeability can be controlled at 0.01ul / cm 2 Further inhibit the corrosion medium invasion. The scheme not only solves the corrosion problem of copper and steel material compatibility in industrial instrument connection, but also reduces the production and later maintenance cost through simplifying the structure, and is especially suitable for the long-term reliable connection demand of harsh working conditions such as petroleum chemical industry, offshore platform and the like.

[0024] The material of nut 1 is carbon steel, and the material of plug-in part 2 is carbon steel. The utility model discloses that the nut 1 and plug-in part 2 are manufactured by using the same carbon steel material, realize that the potential difference of both is zero (DE=0mV), and the formation condition of galvanic corrosion primary cell is completely eliminated. In 5% NaCl salt spray environment, after 500 hours test. The carbon steel homogenous material system makes the tensile strength reach 450MPa or more synchronously, avoids the stress corrosion cracking risk caused by the difference of dissimilar metal thermal expansion, and simultaneously simplifies the processing technology and reduces the production cost. The design realizes the maintenance-free of whole life cycle through the consistency of material on the basis of maintaining excellent corrosion resistance, and is especially suitable for the harsh working conditions such as offshore platform, chemical pipeline and the like that need to bear high frequency vibration and temperature alternation.

[0025] The surface of nut 1 is galvanized with a first coating layer, and the material of the first coating layer is zinc or zinc-aluminum-magnesium or ceramic or non-metal material. The surface of plug-in part 2 is galvanized with a second coating layer, and the material of the second coating layer is zinc or zinc-aluminum-magnesium or ceramic or non-metal material.

[0026] The utility model discloses that the nut 1 and plug-in part 2 are manufactured by using the same carbon steel material, realize that the potential difference of both is zero (DE=0mV), and the formation condition of galvanic corrosion primary cell is completely eliminated. In 5% NaCl salt spray environment, after 500 hours test. The carbon steel homogenous material system makes the tensile strength reach 450MPa or more synchronously, avoids the stress corrosion cracking risk caused by the difference of dissimilar metal thermal expansion, and simultaneously simplifies the processing technology and reduces the production cost. The design realizes the maintenance-free of whole life cycle through the consistency of material on the basis of maintaining excellent corrosion resistance, and is especially suitable for the harsh working conditions such as offshore platform, chemical pipeline and the like that need to bear high frequency vibration and temperature alternation.

[0027] The plug-in end is formed on one side of the plug-in part 2 close to the instrument, and the plug-in hole is formed on the instrument, the plug-in end is in interference fit with the plug-in hole, the inner wall of the plug-in hole is electroplated with a third coating, and the third coating is made of zinc or zinc-aluminum-magnesium or ceramic or non-metal material.

[0028] The utility model discloses a tight mechanical connection is formed through the interference fit of plug-in end and plug-in hole, and the synergies of third coating are combined, and external corrosive medium is effectively isolated from invading. Zinc or zinc-aluminum-magnesium coating layer preferentially occurs sacrificial anode reaction, and the base metal is continuously protected, and ceramic or non-metal coating layer is blocked electrochemical corrosion path through physical isolation. The interference fit structure eliminates the assembly gap, avoids fretting wear caused by vibration, simultaneously ensures that the contact interface pressure is evenly distributed, prevents local electrolyte gathering. The introduction of third coating makes the inner wall of plug-in hole and plug-in end form the same potential or insulation barrier, completely eliminates the corrosion risk of dissimilar metal contact, and significantly improves the long-term sealing performance and structural stability of instrument interface in humid, salt fog and other harsh environments.

[0029] The second thread 21 is formed on one side of the plug-in part 2 close to the instrument, and the threaded hole is formed in the instrument, the plug-in part 2 is in threaded fit with the instrument, the inner wall of the threaded hole is electroplated with a fourth coating, and the fourth coating is made of zinc or zinc-aluminum-magnesium or ceramic or non-metal material.

[0030] The threaded structure ensures the detachable and repeatable assembly characteristics of the plug-in part 2 and the instrument, and the fourth coating on the inner wall forms a continuous protection interface. The zinc or zinc-aluminum-magnesium coating layer continuously neutralizes the corrosive medium through self-repairing characteristics, and the ceramic / non-metal coating layer provides a stable electrically insulating barrier to eliminate the potential difference of the threaded engagement surface. The structure can still maintain long-term corrosion prevention performance under frequent disassembly and assembly conditions.

[0031] The first gasket is made of nylon material. The second gasket is made of nylon material. The utility model further strengthens the corrosion resistance of the corrosion-resistant joint structure through the double electric insulation and sealing effect of the nylon gasket. The first gasket blocks the direct contact between the plug-in part 2 and the instrument, eliminating the risk of galvanic corrosion at the interface; the second gasket forms an elastic sealing layer at the threaded locking part, effectively isolating the intrusion of external moisture, salt fog and other corrosive media. The flexibility of the nylon material can compensate for the assembly tolerance and thermal expansion and contraction deformation, preventing sealing failure caused by stress concentration. The self-lubricating property reduces friction damage during repeated disassembly and assembly, ensuring the integrity of the connection interface during long-term use. The double gasket synergistic effect makes the joint structure remain stable and protective performance under complex conditions such as vibration and temperature difference alternation.

[0032] The surfaces of the nut 1 and the insert 2 are sprayed with epoxy resin. A continuous and dense chemical protection barrier is formed by the epoxy resin spraying, effectively isolating oxygen, moisture and corrosive media from contacting the metal substrate. The epoxy resin layer, with excellent chemical inertness, can resist the corrosion of corrosive media such as acid, alkali and salt, and at the same time eliminate the electrochemical corrosion path caused by surface potential difference. Its high adhesion characteristics ensure that the coating does not peel off under working conditions such as vibration and temperature difference deformation, and long-term maintenance of complete protection. A gradient protection system is formed with the internal metal plating layer, significantly improving the comprehensive protection performance in complex corrosive environments. The spraying process can also cover the structural details, making up for the protection defects of the parts that are difficult to reach by mechanical processing, and achieving all-round corrosion protection.

[0033] Obviously, the above embodiments of the present application are only examples for clearly illustrating the present application, and are not intended to limit the embodiments of the present application. For those skilled in the art, various obvious changes, readjustments and substitutions can be made without departing from the scope of the present application. Here, it is not necessary and impossible to enumerate all the embodiments. Any modification, equivalent substitution and improvement made within the spirit and principle of the present application shall be included in the protection scope of the claims of the present application.

Claims

1. A corrosion resistant joint structure, characterized by, The nut (1) and the plug-in part (2) are included, the plug-in part (2) is plugged in the instrument, the first thread is formed on the side of the plug-in part away from the instrument, the nut (1) is screwed in the first thread, the potential of the material of the nut (1) and the plug-in part (2) is similar or the same.

2. The corrosion-resistant joint structure according to claim 1, characterized by The material of the nut (1) is carbon steel, and the material of the plug-in part (2) is carbon steel.

3. The corrosion-resistant joint structure according to claim 1, characterized by The surface of the nut (1) is electroplated with a first coating, and the material of the first coating is zinc or zinc-aluminum-magnesium or ceramic or non-metal material.

4. The corrosion-resistant joint structure according to claim 1, characterized by The surface of the plug-in part (2) is electroplated with a second coating, and the material of the second coating is zinc or zinc-aluminum-magnesium or ceramic or non-metal material.

5. The corrosion-resistant joint structure according to claim 1, characterized by The side of the plug-in part (2) close to the instrument is formed with a plug-in end, the instrument is formed with a plug-in hole, the plug-in end is interference fit with the plug-in hole, the inner wall of the plug-in hole is electroplated with a third coating, and the third coating is zinc or zinc-aluminum-magnesium or ceramic or non-metal material.

6. The corrosion-resistant joint structure according to claim 1, characterized by The side of the plug-in part (2) close to the instrument is formed with a second thread (21), the instrument is formed with a threaded hole, the plug-in part (2) is screwed with the instrument, the inner wall of the threaded hole is electroplated with a fourth coating, and the material of the fourth coating is zinc or zinc-aluminum-magnesium or ceramic or non-metal material.

7. The corrosion-resistant joint structure according to claim 1, characterized by The first gasket is arranged between the plug-in part (2) and the instrument, and the first gasket is made of nylon material.

8. The corrosion-resistant joint structure of claim 1, wherein The second gasket is arranged between the nut (1) and the plug-in part (2), and the second gasket is made of nylon material.

9. The corrosion-resistant joint structure of claim 1, wherein The surfaces of the nut (1) and the plug-in part (2) are sprayed with epoxy resin.

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