CN100410001C - A method for manufacturing high-strength self-sealing aluminum-plastic composite pipe joints - Google Patents

Abstract

The invention relates to a manufacturing method of an aluminum-plastic composite pipe joint capable of realizing high-strength connection and self-sealing effect. The method includes the processing technology of the main body of the pipe joint and the matching parts, and the specific steps are as follows: ① the pipe joint is made of stainless steel material, ② at least one outer pipe thread is processed on the main body, and the cone apex angle is set at the beginning of the outer pipe thread. For the cone-shaped sealing table between 3-7 degrees, the outer diameter of the port is larger than the inner diameter of the connected pipe, but not more than 1.5mm, and the height value is selected between the inner diameter and outer diameter of the composite pipe. ③At one end of the hex lock nut, set and process a locking platform composed of inner and outer conical surfaces. The inner surface and the outer surface of the sealing platform have the same cone vertex angle, and the initial value of the distance between the two conical surfaces Greater than the wall thickness of the composite pipe, but not greater than 0.6mm.

Description

A method for manufacturing high-strength self-sealing aluminum-plastic composite pipe joints

technical field

The invention relates to the manufacturing technology of connecting pipe fittings of aluminum-plastic composite pipes, in particular to a manufacturing method of pipe joints of aluminum-plastic composite pipes capable of realizing high-strength connection and self-sealing effect.

Background technique

More than ten years of application development process and domestic and foreign application practice have proved that aluminum-plastic composite pipes have obvious advantages in performance and price as small-diameter indoor pipes, and have remarkable characteristics of anti-rust and anti-corrosion. However, the defects of the existing composite pipe connecting pipe fittings have greatly hindered its popularization and application.

The first generation of ferrule-type copper pipe joints achieves the purpose of sealing by turning the nut and pressing the split ring. After 1997, the second generation of crimping copper joints began to appear. The steel sleeve was permanently deformed by using a special crimping tool, and the pipe and the joint core were crimped into a whole. The advantages are sealing, safety, and high installation efficiency. The disadvantage is that it cannot be disassembled, and the flow resistance is significantly increased at the pipe joint. The Ministry of Construction recommended the use of new types of pipes such as aluminum-plastic pipes after research, and they were quickly extended to the fields of liquid transportation pipeline systems such as hot and cold water, gas, compressed gas, solar energy, heating, medical treatment, pure water, and chemical engineering in industrial and civil engineering. However, the technical development of domestic aluminum-plastic composite pipe joints does not match the development of the aluminum-plastic pipe manufacturing industry. At present, the first-generation ferrule-type copper joints are still the mainstream in the market, and the second-generation steel sleeve clamp-type copper joints can also be seen. Inventors at home and abroad have had many attempts to improve the specific structure, but it is inevitable to use rubber sealing parts to solve the leakage problem. The foreign standards of O-ring rubber that play a key role in various pipe joints require that the "compression set rate" be less than 20%. Therefore, EPDM rubber sealing rings with better compression properties have been widely used abroad, but the installation cannot be guaranteed. The damage to such components during the process and the occurrence of aging failure under long-term application conditions. However, traditional NBR sealing rings are still widely used in China, and NBR sealing rings cannot guarantee a 50-year service life at all. The steel-sleeved crimp-type copper joint is currently an advanced joint used for aluminum-plastic composite pipes. It has high connection reliability, good resistance to cold and heat cycles, and can basically achieve zero leakage in the connection of aluminum-plastic pipes. Therefore, it has been widely used. Applied to hot and cold water supply, heating, gas fields. However, it still cannot accurately grasp the proper pre-tightening force during the connection operation, and it is impossible to avoid damage to the sealing parts during the connection process, which directly affects the quality and aging of the seal. Moreover, the mixed use of copper and aluminum is more prone to electrochemical reactions and rust, so it cannot be used in green pipelines with corrosion and high water quality requirements, such as gas, chemical, pharmaceutical and other pipeline systems, which have greater restrictions; the production cost is relatively high. high.

Contents of the invention

The purpose of this invention is to provide a new composite pipe joint design and processing technology, so that it can realize high-strength connection, excellent sealing performance and long-term stability under the premise of omitting rubber sealing elements; and can realize freedom , repeated loading and unloading and has the characteristics of small flow resistance.

The key design idea of the present invention is the creep allowance automatic adjustment technology under the cooperation and compression of the small-angle large-area conical surface produced by summarizing a large number of experimental data.

The method includes the processing technology for the pipe joint main body and supporting parts, and the specific steps are as follows:

①The main body of the pipe joint and the matching parts are made of stainless steel.

②Choose at least one channel opening to process the outer pipe thread on the main body of the two-way, three-way, or more than three-way hollow pipe joints, set and process a sealing platform with a cone-shaped outer surface at the beginning of the outer pipe thread, and control The cone vertex angle of the outer cone surface of the sealing table is between 3-7 degrees, the outer diameter of the port of the sealing table is larger than the inner diameter of the connected pipe, but not more than 1.5mm, and the height of the sealing table is selected between the inner diameter of the connected composite pipe and between outer diameters.

③ Select a hexagonal lock nut as a pair that matches the outer pipe thread on the main body, set and process a locking platform composed of inner and outer tapered surfaces at one end of the nut, so that the inner and outer tapered surfaces of the locking platform The surface and the outer surface of the sealing platform have the same cone angle. When assembled together, the distance between the two cone surfaces at the beginning of the screw-in outer pipe thread of the locking platform is greater than the wall thickness of the connected aluminum-plastic composite pipe. But not more than 0.6mm.

It is the key of the present invention to choose a small cone angle of 3-7 degrees and cooperate with two large cone surfaces formed by the appropriate height of the cone surface to exert pressure on the aluminum-plastic composite pipe wall. According to the above design, the inner surface of the locking table and the outer surface of the sealing table are pressed together to fully meet the basic requirements of compression resistance and sealing of aluminum-plastic pipe joints. The process of tightening the lock nut is the process of increasing the pressure on the composite pipe wall, and is also the process of rubbing forward along the outer wall of the composite pipe. The polyethylene plastic inside and outside the composite pipe wall will produce elastic deformation under the action of increasing force, and some materials will creep to the place with low pressure. If we open appropriate grooves on the cone surface of the sealing table to allow the material to flow in, on the one hand, the airtightness can be enhanced, and on the other hand, the axial anti-off ability can be strengthened, so that the connection strength and sealing performance can be greatly improved.

Experiments have proved that the value ranges of the above-mentioned cone top angle and sealing table height are scientific parameters obtained through simulation calculations, taking into account non-destructive deformation, processing procedures, sealing performance, and friction distribution. Positive effect of strength self-sealing.

The embodiments given below in conjunction with the accompanying drawings further illustrate how the object of the present invention is achieved.

Description of drawings

Fig. 1 is a structural schematic diagram of the main part of the pipe joint.

Fig. 2 is a schematic structural view of the main part of the pipe joint in another embodiment.

Fig. 3 is a structural schematic diagram of a lock nut of a matching pair of pipe joints.

Figure 4 is a schematic diagram of the structure of the application state of this design.

In the figure, 1 is the main part of the hollow pipe joint, 2 is the outer pipe thread, 3 is the sealing platform, 4 is the annular rolling sealing groove, 5 is the annular groove, 6 is the tapered thread groove, 7 is the hexagonal lock nut, and 8 is the lock The tight platform, 9 represents a section of cylindrical surface adjacent to the inner tapered surface of the locking platform, and 10 represents the plastic edge injected into the ring-shaped rolling sealing groove 4 through rolling and creeping. 11 represents the aluminum material in the aluminum-plastic composite pipe.

Detailed ways

As can be seen from the given embodiment of the accompanying drawings, the concrete steps of the present invention are as follows:

①The main body of the pipe joint and the matching parts are made of stainless steel.

② Process the outer pipe thread at least one channel opening on the main body 1 of the two-way, three-way, or more than three-way hollow pipe joint, and set and process a sealing platform 3 whose outer surface is in the shape of a cone at the beginning of the outer pipe thread 2 , control the cone apex angle of the outer cone surface of the sealing table 3 between 3-7 degrees, the outer diameter of the port of the sealing table 2 is greater than the inner diameter of the connected pipe, but not greater than 1.5mm, and the height of the sealing table 3 is selected at the connected Between the inner diameter and outer diameter of the composite pipe,

③ Select a hexagonal lock nut 7 as a pair matching the outer pipe thread 2 on the main body, set and process a locking platform 8 composed of inner and outer tapered surfaces at one end of the nut, so that the locking platform The inner surface of 8 has the same cone angle as the outer surface of sealing platform 3, and the distance between the two cone surfaces is greater than the wall of the connected aluminum-plastic composite pipe at the beginning of screwing-in outer pipe thread 2 of locking platform 8 Thick, but not greater than 0.6mm.

In order to further improve the connection strength and self-sealing performance, an annular groove 5 or a rectangular tapered thread groove 6 is further processed in the middle of the tapered surface of the sealing table 3 processed in the above step ② or near the root. The groove width 2 -4mm, depth 0.4-0.6mm.

In the above step ③, the height of the locking platform 8 is controlled between 2/3-3/4 of the height of the sealing platform 3, and a section of guide cylindrical surface 9 with a height of 2-8 mm is set at the port of the inner tapered surface of the locking platform 8. 1. An annular rolling sealing groove 4 is processed between the inner conical surface of the locking platform 8 and the inner pipe thread of the hexagonal lock nut 7, the width is 1.5-5mm, and the depth is 1-2.5mm.

The process of tightening the hex lock nut 7 is the process of increasing the pressure on the composite pipe wall, and it is also the process of rubbing the plastic forward along the outer wall of the composite pipe. The polyethylene plastic inside and outside the composite pipe wall is constantly increasing. Under the pushing and rubbing of pressure, part of the material will creep to the place with less pressure. Finally inject the annular groove 5 or the tapered thread groove 6 to form a ring-shaped or tapered thread-shaped rib that can play the role of sealing and tensile resistance. The excessive material flows into the annular calendering sealing groove 4 to form a plastic edge 10, which will be firmly pressed on the channel opening by the lock nut 7, which plays a key role in high-strength connection and self-sealing.

In order to achieve a better fit between the inner surface of the locking platform 8 and the outer surface of the sealing platform 3, at least one channel opening on the hollow pipe joint body 1 in the above step ② is processed with an outer pipe thread and a hexagon in step ③. The inner pipe threads of the locking nut 7 are matched accordingly, and the axial length of the pipe threads is between 16-22mm. It can adapt to the needs of aluminum-plastic composite pipes of different calibers.

The main body 1 of the hollow pipe joint adopts two-way, or three-way, or more than three-way structural forms, and all access ports and supporting parts are made according to the method described in claim 1. The special connecting pipe fittings, or the main body 1 of the hollow pipe joint adopts part of the common metal pipe joint port structure and supporting parts, so as to form a conversion connecting pipe fitting between the composite pipe and the ordinary metal pipe.

When carrying out the connection operation, the matching hexagonal lock nut 7 should be selected according to the internal and external diameter of the specific aluminum-plastic composite pipe to be set on the interface end, and then the port of the connected pipe should be expanded into a tapered horn shape according to the size of the corresponding sealing platform 3 . Insert the sealing platform 3, put the bell port against the root of the sealing platform 3, and tighten the hex lock nut 7. The degree of pre-tightening force is subject to the occurrence of rigid resistance, which is easy to grasp and will not have adverse consequences on the seal. During the locking process, the plastic edge 10 formed automatically by rolling the plastic and the corrugation on the inner wall of the composite pipe play an important role in improving the sealing performance, connection strength and connection life of the joint.

Claims (4)

1. the preparation method of a high strength self-sealing composite aluminium-plastic pipe union, this method comprises the processing technology to pipe joint body and supporting even part, it is characterized in that concrete step is as follows:

1. pipe joint body and supporting even part are chosen the stainless steel material processing and fabricating,

2. go up at least one place, passway in two logical or threeways or the hollow tube adapter body (1) more than the threeway and process external pipe thread (2), top setting and processing outer surface at external pipe thread (2) are the sealing platform (3) of cone shape, the cone-apex angle of the male cone (strobilus masculinus) of control sealing platform (3) is between the 3-7 degree, sealing platform (3) port outside diameter greater than but be no more than the internal diameter of 1.5mm institute tube connector, the sealing platform (3) height value be selected in connect between the internal diameter and external diameter of multiple tube

3. the supporting even part of selecting a hexagonal locking nut (7) conduct and main body upper exterior tube screw thread (2) to mate, in an end setting of this nut, process a locking platform (8) that combines by the inside and outside conical surface, make the inner surface of locking platform (8) have identical cone-apex angle with the outer surface of sealing platform (3), the distance between two conical surfaces the value of the section start of locking platform (8) precession external pipe thread (2) greater than but be no more than the wall thickness of the PAP that 0.6mm connects.

2. according to the preparation method of the said high strength self-sealing composite aluminium-plastic pipe union of claim 1, it is characterized in that the middle part of sealing platform (3) conical surface that is processed into during step 2. or near the taper thread groove (6) that further processes endless groove (5) or rectangle on the position of root, this well width 2-4mm, degree of depth 0.4-0.6mm.

3. according to the preparation method of the said high strength self-sealing composite aluminium-plastic pipe union of claim 1, it is characterized in that the height of locking platform (8) was controlled to be between the 2/3-3/4 of sealing platform (3) height during step 3., the port of the inner conical surface of locking platform (8) is provided with the high one section guide cylinder face (9) of 2-8mm, locking platform (8) inner conical surface processes annular calendering seal groove (4) between hexagonal locking nut (7) Internal Pipe Thread, width is 1.5-5mm, and the degree of depth is 1-2.5mm.

4. according to the preparation method of the said high strength self-sealing composite aluminium-plastic pipe union of claim 1, it is characterized in that hollow tube adapter body described in step 2. (1) goes up at least one place, passway and processes the 3. corresponding coupling of Internal Pipe Thread of middle hexagonal locking nut (7) of external pipe thread and step, the axial length of gas thread is between the 16-22mm.

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