Composite pipe connecting structure, injection mold and implementation method

Abstract

The present application relates to the technical field of composite pipe, in particular to a composite pipe connecting structure, an injection mold and an implementation method, the composite pipe connecting structure comprises a composite pipe, the composite pipe is provided with a spiral reinforcing rib protruding outward, the composite pipe is internally provided with a steel pipe layer, the two ends of the composite pipe are cross sections, the cross sections are injection molded with flange connection type pipe fittings, the flange connection type pipe fittings wrap the outside, the inside and the end of the cross section; the minimum outer diameter of the tubular part of the flange connection type pipe fitting is greater than the maximum diameter of the highest point of the spiral reinforcing rib of the composite pipe, and the tubular length is greater than the pitch of the spiral reinforcing rib; the composite pipe connecting structure avoids the problem that the composite pipe inner wall and the flange connection type pipe fitting may crack at the fusion position, and the steel pipe in the composite pipe will not be exposed; the injection mold uses a core, avoids the overflow problem, and facilitates the taking out of the product after the flange connection type pipe fitting is injection molded.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of composite pipe, in particular to a composite pipe connecting structure, an injection mold and an implementation method. BACKGROUND

[0002] A patent with the authorized announcement number CN114017548B discloses a kind of composite pipe for conveying gas with no halogen, low smoke and low toxicity and its processing method and application, the intermediate structure layer of the composite pipe is steel pipe layer, the inside and outside of steel pipe layer are flame-retardant layer, antistatic layer, two ends are injected with flange connection type pipe fitting and are sleeved with flange, pipe wall has outwardly convex spiral reinforcing rib groove.Processing method is along the longitudinal direction of steel strip reinforcing rib groove is pressed, spiral is curled, welding is carried out along spiral lap joint, while steel pipe is heated, extruded flame-retardant layer, antistatic layer material is covered together by co-extrusion die head, is rolled to the inside and outside wall of steel pipe, after cooling, according to the demand cutting length gets semi-finished product, sleeve flange, using direct injection method in the both ends of semi-finished product injection flange connection type pipe fitting, obtains no halogen, low smoke and low toxicity composite pipe.

[0003] In prior art, flange connection type pipe fitting of injection composite pipe, the core in injection mold is integrated structure, flange connection type pipe fitting covers the outside and end of composite pipe, does not cover the inside of composite pipe, this kind of connecting structure can crack in the position of composite pipe inner wall and flange connection type pipe fitting fusion, make the steel pipe in the inside of composite pipe expose and be corroded;And because the cross section of composite pipe is not same annular, injection raw material inevitably overflows in convex spiral reinforcing rib groove position;And because the thermal expansion coefficient of steel core and non-metallic material is 10 times different, demoulding is difficult after injection. SUMMARY

[0004] The main purpose of the present application is to provide a kind of composite pipe connecting structure, injection mold and implementation method, to solve the problems of possible cracking, overflow and demoulding difficulty in prior art.

[0005] In order to achieve the above-mentioned purpose, the present application provides a kind of composite pipe connecting structure, including composite pipe, the spiral reinforcing rib of composite pipe is outwardly protruding, the steel pipe layer is arranged in the inside of composite pipe, the both ends of composite pipe are cross section, flange connection type pipe fitting is injection molded in cross section, and flange connection type pipe fitting wraps the outside, inside and end of cross section.

[0006] Further, the minimum outer diameter of the tubular part of the flange connection type pipe fitting is greater than the maximum diameter of the highest point of the spiral reinforcing rib of the composite pipe, and the tubular length is greater than the pitch of the spiral reinforcing rib.

[0007] Further, the outside of the flange connection type pipe fitting is flange-shaped, and the inside of the flange connection type pipe fitting is a reinforcing ring, which is located at the end of the inner surface of the composite pipe.

[0008] Further, the reinforcing ring is provided with a certain slope at the composite position between the reinforcing ring and the inner wall of the composite pipe at the other end of the pipe fitting head of the flange connection type.

[0009] The application further provides an injection mold for processing the composite pipe connecting structure, which comprises a core and a cavity, the core comprises a front ring, an expansion ring, a rear ring and a fixed mold plate arranged in sequence from left to right, the rear ring is fixedly connected with the fixed mold plate, the expansion ring is movably connected between the front ring and the rear ring, the expansion ring is spliced by a plurality of splicing blocks, and the splicing blocks are connected with hydraulic cylinders for moving the splicing blocks; when the hydraulic cylinders are in an extended state, the outer diameter of the expansion ring is greater than the outer diameter of the rear ring and slightly greater than the inner diameter of the composite pipe; when the hydraulic cylinders are in a contracted state, the outer diameter of the expansion ring is less than the outer diameter of the rear ring.

[0010] Further, the splicing blocks comprise large splicing blocks with large outer ends and small inner ends and small splicing blocks with small outer ends and large inner ends.

[0011] Further, the cavity comprises an upper cavity and a lower cavity which can be spliced with each other.

[0012] The application further provides an implementation method of the composite pipe connecting structure, characterized by using the injection mold to perform injection molding, and comprising the following steps:

[0013] S1, the hydraulic cylinders drive the small splicing blocks and the large splicing blocks to be contracted in sequence, the composite pipe to be injection molded is sleeved on the core, and a certain spacing is left between the cross section and the fixed mold plate;

[0014] S2, the upper cavity moves downward and the lower cavity moves upward to wrap the end portion of the composite pipe, and then the mold is closed;

[0015] S3, the hydraulic cylinders drive the large splicing blocks and the small splicing blocks to be extended in sequence, the expansion ring is tightly attached to the inner wall of the composite pipe, and the molten non-metallic material is injected through the gate of the injection mold;

[0016] S4, after pressure maintaining and cooling, the hydraulic cylinders drive the small splicing blocks and the large splicing blocks to be contracted in sequence, the core retreats, the upper cavity moves upward and the lower cavity moves downward to open the mold;

[0017] S5, the product after the flange connection type pipe fitting is taken out, and the connecting structure of one end of the composite pipe is formed;

[0018] S6, the iron flange is sleeved on the composite pipe, and the connecting structure of the other end of the composite pipe is formed according to the steps S1 to S5.

[0019] The composite pipe connecting structure avoids the problem that the composite pipe inner wall and the flange connection type pipe fitting may crack at the fusion position, and the steel pipe inside the composite pipe will not be exposed.

[0020] The injection mold core of this invention avoids the problem of overflow during injection by setting a telescopic ring and a rear ring. The composite tube has outwardly protruding spiral reinforcing rib grooves, which means that the cross-section at any position is not the same ring shape. The injection raw material inevitably overflows inside the protruding spiral reinforcing rib grooves. By designing that the outer diameter of the rear ring is smaller than the inner diameter of the composite tube and the outer diameter of the telescopic ring is larger than the inner diameter of the composite tube when the hydraulic cylinder is extended, the overflow problem is avoided.

[0021] This invention, by setting a telescopic ring, allows the hydraulic cylinder to retract after injection molding, causing the telescopic ring to detach from the inner wall of the composite pipe, making it convenient to remove the product after injection molding of flange-connected pipe fittings. Attached Figure Description

[0022] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0023] Figure 1 This is a schematic diagram of the structure of Example 1 of the composite pipe connection structure;

[0024] Figure 2 This is a schematic diagram of the structure of Example 2 of the composite pipe connection structure;

[0025] Figure 3 This is a schematic diagram of a composite pipe connection structure in the prior art;

[0026] Figure 4 This is a schematic diagram of the core structure when the telescopic ring extends in Example 1 of the injection mold;

[0027] Figure 5 for Figure 4 A cross-sectional diagram of AA in the middle section;

[0028] Figure 6 for Figure 4 A cross-sectional diagram of BB;

[0029] Figure 7 This is a schematic diagram of the cavity structure in Example 1 of the injection mold;

[0030] In the diagram: 1. Composite pipe; 2. Spiral reinforcing rib; 3. Cross section; 4. Flange connection pipe fittings; 5. Front ring; 6. Expansion ring; 7. Rear ring; 8. Fixed template; 9. Hydraulic cylinder; 10. Large splicing block; 11. Small splicing block; 12. Upper cavity; 13. Lower cavity. Detailed Implementation

[0031] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0032] like Figure 3 As shown, the existing composite pipe connection structure has a flange-type fitting 4 covering the outside and end of the composite pipe 1, but not the inside. This can cause cracks at the fusion joint between the inner wall of the end of the composite pipe 1 and the flange-type fitting, resulting in the steel pipe inside the composite pipe 1 being exposed and corroded. Furthermore, since the cross-section of the composite pipe is not uniformly annular, the injection molding material inevitably overflows at the raised spiral reinforcing ribs. Moreover, due to the 10-fold difference in the coefficient of thermal expansion between the steel core and the non-metallic material, demolding after injection molding is difficult.

[0033] Example 1 of composite pipe connection structure

[0034] like Figure 1 As shown, a composite pipe connection structure includes a composite pipe 1 with outwardly protruding spiral reinforcing ribs 2. The composite pipe 1 has an internal steel pipe layer. The length of the composite pipe 1 is determined according to requirements. Both ends of the composite pipe 1 are cross-sections 3, and these cross-sections 3 are injection-molded with non-metallic flange-type fittings 4 for connecting flanges. The flange-type fittings 4 enclose the outside, inside, and ends of the cross-sections 3. The outside of the flange-type fittings 4 is flange-shaped, and the inside of the flange-type fittings 4 has a reinforcing ring 401 with a wall thickness of 1-5 mm and a width of 20-50 mm. The minimum outer diameter of the tubular portion of the flange-type fittings 4 is greater than the maximum diameter of the highest point of the spiral reinforcing ribs of the composite pipe, ensuring that the reinforcing ribs are completely enclosed by the flange-type fittings 4. The tubular length is greater than the pitch of the spiral reinforcing ribs 2, and the head is injection-molded with a waterline groove.

[0035] The non-metallic raw materials used in the composite pipe connection structure are selected according to different uses. For composite pipes used in coal mines, they must have flame-retardant and anti-static properties, while for non-coal mines and tunnels, they must have flame-retardant properties.

[0036] In this embodiment, the composite pipe connection structure, the flange connection type pipe fitting 4 not only wraps the outside and end of the composite pipe 1, but also wraps the inside of the composite pipe 1, so that no cracks will appear at the fusion position between the inner wall of the end of the composite pipe 1 and the flange connection type pipe fitting.

[0037] Example 2 of composite pipe connection structure

[0038] like Figure 2 As shown, the difference between Embodiment 2 and Embodiment 1 is that the reinforcing ring 401 has a certain slope at the other end of the flange connection pipe fitting 4 and the composite part of the inner wall of the composite pipe 1; the slope is more conducive to the stable transportation of gas and also more conducive to processing and forming.

[0039] Injection mold Example 1

[0040] like Figures 4-7As shown, an injection mold for processing a composite pipe connection structure (Example 1) includes a core and a cavity. The core includes a front ring 5, a telescopic ring 6, a rear ring 7, and a fixed template 8 arranged sequentially from left to right. The rear ring 7 is fixedly connected to the fixed template 8. The telescopic ring 6 is movably connected between the front ring 5 and the rear ring 7. The telescopic ring 6 is composed of multiple splicing blocks, including four large splicing blocks 10 with larger outer ends and smaller inner ends, and four small splicing blocks 11 with smaller outer ends and larger inner ends. The splicing blocks are connected to a hydraulic cylinder 9 that drives the splicing blocks to move. When the hydraulic cylinder 9 is in the extended state, the outer diameter of the telescopic ring 6 is larger than the outer diameter of the rear ring 7 and 0.1-2 mm larger than the inner diameter of the composite pipe 1 to be injection molded. When the hydraulic cylinder is in the retracted state, the outer diameter of the telescopic ring 6 is smaller than the outer diameter of the rear ring 7.

[0041] The cavity includes an upper cavity 12 and a lower cavity 13 that can be spliced ​​together.

[0042] The injection mold of this embodiment can be used to injection mold the composite pipe connection structure in the above embodiment; and the injection-molded composite pipe is easy to remove.

[0043] Injection Molding Method Example

[0044] A method for implementing a composite pipe connection structure, using injection molding as described in Example 1, includes the following steps:

[0045] S1. Hydraulic cylinder 9 drives small splicing block 11 and large splicing block 10 to retract in sequence, so that the composite tube 1 to be injected is inserted into the core. A certain gap is left between the cross section 3 of the composite tube 1 and the fixed template 8.

[0046] S2. The upper cavity 12 moves downward and the lower cavity 13 moves upward, wrapping the end of the composite tube 1, and then the mold is closed.

[0047] S3, hydraulic cylinder 9 drives large splicing block 10 and small splicing block 11 to extend in sequence, telescopic ring 6 is pressed against the inner wall of composite pipe 1, and plasticized non-metallic material melt is injected through injection mold gate;

[0048] S4. After pressure holding and cooling, the hydraulic cylinder 9 drives the small splicing block 11 and the large splicing block 10 to shrink in sequence, the core moves backward, the upper cavity 12 moves upward and the lower cavity 13 moves downward to open the mold.

[0049] S5. After removing the product with the pre-molded flange connection type pipe fitting 4, the connection structure of one end of the composite pipe 1 is completed.

[0050] S6. Insert the iron flange into the composite pipe 1, and complete the forming of the connection structure at the other end of the composite pipe 1 according to steps S1 to S5.

[0051] Using the injection molding method in this embodiment, the composite pipe connection structure after injection molding is easy to remove, and no cracks will appear at the welding position between the end of the composite pipe 1 and the flange connection type pipe fitting 4.

[0052] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. An injection mold for processing composite pipe connection structures, characterized in that, The system includes a core and a cavity. The core includes a front ring (5), a telescopic ring (6), a rear ring (7), and a fixed template (8) arranged from left to right. The rear ring (7) is fixedly connected to the fixed template (8). The telescopic ring (6) is movably connected between the front ring (5) and the rear ring (7). The telescopic ring (6) is composed of multiple splicing blocks. The splicing blocks are connected to a hydraulic cylinder (9) that drives the splicing blocks to move. When the hydraulic cylinder (9) is in the extended state, the outer diameter of the telescopic ring (6) is larger than the outer diameter of the rear ring (7) and slightly larger than the inner diameter of the composite pipe (1). When the hydraulic cylinder is in the retracted state, the outer diameter of the telescopic ring (6) is smaller than the outer diameter of the rear ring (7). The composite pipe connection structure includes a composite pipe (1), the composite pipe (1) is provided with outwardly protruding spiral reinforcing ribs (2), the composite pipe (1) is provided with a steel pipe layer inside, the two ends of the composite pipe (1) are cross sections (3), the cross sections (3) are injection molded with flange connection pipe fittings (4), the flange connection pipe fittings (4) wrap around the outside, inside and end of the cross sections (3); The flange connection type pipe fitting (4) has a flange shape on the outside and a reinforcing ring (401) inside. The reinforcing ring is located at the end of the inner surface of the composite pipe (1).

2. The injection mold for processing composite pipe connection structures as described in claim 1, characterized in that, The minimum outer diameter of the tubular part of the flange connection type pipe fitting (4) is greater than the maximum diameter of the highest point of the spiral reinforcing rib of the composite pipe, and the tubular length is greater than the pitch of the spiral reinforcing rib (2).

3. The injection mold for processing composite pipe connection structures as described in claim 1, characterized in that, The reinforcing ring (401) has a certain slope at the other end of the flange connection pipe fitting (4) and the composite part of the inner wall of the composite pipe (1).

4. The injection mold for processing composite pipe connection structures as described in claim 1, characterized in that, The splicing blocks include a large splicing block (10) with a large outer end and a small inner end, and a small splicing block (11) with a small outer end and a large inner end.

5. The injection mold for processing composite pipe connection structures as described in claim 4, characterized in that, The cavity includes an upper cavity (12) and a lower cavity (13) that can be spliced ​​together.

6. A method for implementing a composite pipe connection structure, characterized in that, Injection molding using the injection mold for processing composite pipe connection structures as described in claim 5 includes the following steps: S1. The hydraulic cylinder (9) drives the small splicing block (11) and the large splicing block (10) to shrink in sequence, so that the composite pipe (1) to be injected is inserted into the core, and a certain gap is left between the cross section (3) and the fixed template (8). S2, the upper cavity (12) moves downward and the lower cavity (13) moves upward, wrapping the end of the composite tube (1) and then closing the mold; S3, the hydraulic cylinder (9) drives the large splicing block (10) and the small splicing block (11) to extend in sequence, the telescopic ring (6) is pressed against the inner wall of the composite pipe (1), and the plasticized non-metallic material melt is injected through the injection mold gate; S4. After pressure holding and cooling, the hydraulic cylinder (9) drives the small splicing block (11) and the large splicing block (10) to shrink in sequence, the core moves backward, and the upper cavity (12) moves upward and the lower cavity (13) downward to open the mold. S5. After removing the pre-molded flange connection pipe fitting (4), the connection structure of one end of the composite pipe (1) is formed. S6. Insert the iron flange into the composite pipe (1) and complete the forming of the connection structure at the other end of the composite pipe (1) according to steps S1 to S5.

Images