A multi-layer co-extrusion die

Abstract

The present invention relates to a multi-layer co-extrusion die, comprising a first extrusion flow channel connected to a first main machine, a second extrusion flow channel connected to a second main machine, and a distributor; the distributor is located between the first extrusion flow channel and the diversion end plate, and a pair of transition flow channels are also arranged between the distributor and the plurality of diversion end plates, the transition flow channel comprising a first connecting pipe connected to the diversion end plate, and a second connecting pipe connected to the first connecting pipe through a flange; the end of one of the first connecting pipe and the second connecting pipe has a protruding portion, and the end of the other of the first connecting pipe and the second connecting pipe has a ball socket portion, the protruding portion matches the ball socket portion, and the ball surface of the protruding portion and the ball socket surface of the ball socket portion fall on the center line of the transition flow channel. Through the coordination of the ball head and the ball socket structure, a circular arc surface contact is formed between the pair of connecting pipes to prevent the problem of material leakage, thereby ensuring that the material thickness at each part of the tube blank is uniform, and better improving the quality of the plastic parts produced by the mold.

Description

Technical Field

[0001] The invention belongs to the technical field of pipe extrusion molding, and in particular relates to a multi-layer co-extrusion die for extruding multi-layer composite pipes. Background Art

[0002] Multilayer composite pipes are products designed for transmitting hot fluids. Traditional multilayer composite pipes are generally extruded through multilayer co-extrusion dies. After the molten material is extruded from the extruder, it is divided into three strands and enters the inner, middle and outer layers of the spiral respectively. Among them, the outer layer flow channel and the inner layer flow channel are usually the same material. After being divided by the distributor, they enter the diversion end plate and the spiral respectively through two flow channels. However, the finished three-layer composite pipe often has the undesirable phenomenon of pipe product wall deviation, which affects the quality of the product. Summary of the invention

[0003] In order to solve the above technical problems, the purpose of the present invention is to provide a multi-layer co-extrusion die capable of overcoming the wall deviation of tubular products.

[0004] In order to achieve the purpose of the above invention, the present invention adopts the following technical scheme: a multi-layer co-extrusion mold, including a first extrusion flow channel connected to a first main machine, a second extrusion flow channel connected to a second main machine, a distributor, a plurality of diversion end plates, a spiral, a mouth mold and a core mold, the distributor is located between the second extrusion flow channel and the diversion end plate, and a pair of transition flow channels are also arranged between the distributor and the plurality of diversion end plates, the transition flow channel includes a first connecting pipe connected to the diversion end plate, and a second connecting pipe connected to the first connecting pipe through a flange; the end of one of the first connecting pipe and the second connecting pipe has a spherical protrusion, and the end of the other of the first connecting pipe and the second connecting pipe has a socket, the spherical protrusion matches the socket, and the spherical surface of the spherical protrusion and the spherical socket surface of the socket fall on the center line of the transition flow channel.

[0005] In the above technical solution, preferably, the first connecting pipe is threadedly connected to the diversion end plate.

[0006] In the above technical solution, preferably, the other end of the second connecting tube opposite to the spherical protrusion or the socket is connected to the distributor through a third component, and a gasket is also provided between the distributor and the second connecting tube.

[0007] In the above technical solution, preferably, a pair of shallow grooves are provided on the distributor, and the gasket and the other end of the second connecting pipe are embedded in the shallow grooves.

[0008] In the above technical solution, preferably, the material of the gasket is copper.

[0009] In the above technical solution, preferably, the distributor has two discharge ports, and the distributor also has a pair of adjustment screws for adjusting the sizes of the two discharge ports respectively.

[0010] In the above technical solution, preferably, an adjusting screw sleeve is fixedly connected to the outer side of the distributor, the adjusting screw is threadedly connected to the adjusting screw sleeve, and the terminal end of the adjusting screw can move radially relative to the discharge port; the terminal end of the adjusting screw has a spherical outer surface.

[0011] In the above technical solution, preferably, the diversion end plate includes a first diversion end plate, a second diversion end plate and a third diversion end plate; the spiral body is provided with an outer flow channel, an intermediate flow channel and an inner flow channel, wherein the first diversion end plate and the third diversion end plate are respectively connected to the outer flow channel and the inner flow channel, and a pair of transition flow channels are respectively connected to the distributor and the first diversion end plate and the third diversion end plate.

[0012] Compared with the prior art, the present invention achieves the following beneficial effects: the present invention cooperates a pair of transition flow channels through a ball head and a ball socket structure to form an arc surface contact between a pair of connecting pipes, which can prevent material leakage, thereby ensuring that the material thickness at various locations of the tube blank is uniform, and better improving the quality of plastic parts produced by the mold. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Attached Figure 1 A cross-sectional view of an embodiment of the present application;

[0014] Attached Figure 2 For attachment Figure 1 The enlarged view of point A in the middle;

[0015] Attached Figure 3 For attachment Figure 1 Section along BB;

[0016] Attached Figure 4 The schematic diagram of the splitting of the transition flow channel;

[0017] Attached Figure 5 is a cross-sectional view of the first connecting pipe;

[0018] Attached Figure 6 is a front view of the second connecting pipe;

[0019] Attached Figure 7 The three-dimensional transition channel Figure 1 ;

[0020] Attached Figure 8 The three-dimensional transition channel Figure 2 ;

[0021] Wherein: 10, first extrusion flow channel; 1, second extrusion flow channel; 11, distributor; 101, distribution inlet; 110, shallow groove; 111, discharge port; 112, adjusting screw; 1120, spherical outer surface; 113, adjusting screw sleeve; 12, diversion end plate; 121, first diversion end plate; 122, second diversion end plate; 123, third diversion end plate; 13, spiral body; 131, outer flow channel; 132, middle flow channel; 133, inner flow channel; 14, mouth die; 15, core die; 2, transition flow channel; 201, spherical protrusion; 202, ball socket; 21, first connecting pipe; 22, second connecting pipe; 23, flange; 3, gasket. DETAILED DESCRIPTION

[0022] In order to explain the technical content, structural features, objectives and effects of the invention in detail, the following will be described in detail with reference to the embodiments and the accompanying drawings, wherein the positional relationships of "front" and "rear" in this specification are respectively the same as those in the accompanying drawings. Figure 1 The front and rear correspond to each other.

[0023] In view of the problem of wall deviation in the existing pipe products, the researchers conducted detailed inspections on the defective products and found that the thickness of the material in each layer of the pipe blank was uneven at the beginning of extrusion. When further exploring the cause, it was found that in the two transmission paths from the distributor to the diversion end plate, the material was transmitted through two flow channels in the past. The lengths of the two flow channels need to be kept precisely consistent, and the processing error is within 0.5mm, otherwise there will be gaps, which may lead to leakage, and then the amount of material reaching the spiral inside the mold is different, resulting in different thicknesses and flow rates of the material coming out of the spiral, resulting in the phenomenon of wall deviation of the pipe products.

[0024] This embodiment provides a multi-layer co-extrusion die, Figure 1 The mold is shown to include a first extrusion flow channel 10 connected to a first main machine, a second extrusion flow channel 1 connected to a second main machine, a distributor 11, a plurality of diverter end plates 12, a spiral body 13, a die 14, and a core die 15. The diverter end plate 12 includes a first diverter end plate 121, a second diverter end plate 122, and a third diverter end plate 123, and the spiral body 13 has an outer flow channel 131, an intermediate flow channel 132, and an inner flow channel 133; the first diverter end plate 121 and the third diverter end plate 123 are connected to the outer flow channel 131 and the inner flow channel 133, respectively.

[0025] Combination Figure 1 , Figure 2 , Figure 4 , Figure 7 and Figure 8 A pair of transition channels 2 are provided between the distributor 11 and the flow dividing end plate 12. The transition channel 2 includes a first connecting pipe 21 (see FIG. Figure 5 ) and a second connecting pipe 22 connected to the first connecting pipe 21 via a flange 23 (see Figure 6 The first connecting tube 21 has a socket portion 202 at the other end, and the second connecting tube 22 has a spherical protrusion 201 at one end connected to the socket portion 202. The socket portion 202 matches the spherical protrusion 201, and the spherical surface of the spherical protrusion 201 and the spherical socket surface of the socket portion 202 fall on the center line of the transition channel 2.

[0026] Combination Figure 1 and Figure 4 As shown, the other end of the second connecting tube 22 opposite to the spherical protrusion 201 is connected to the distributor 11 through a third component, and a gasket 3 is provided between the distributor 11 and the second connecting tube 22. The material of the gasket 3 is copper. A pair of shallow grooves 110 are provided at the end where the distributor 11 is connected to the second connecting tube 22, and the second connecting tube 22 and the gasket 3 are embedded in the shallow grooves 110.

[0027] Combination Figure 3 and 4 As shown, the distributor 11 has a distribution inlet 101 and two discharge ports 111, and the distributor 11 also has a pair of adjustment screws 112 respectively used to adjust the sizes of the two discharge ports 111. An adjustment screw sleeve 113 is fixedly connected to the outer side of the distributor 11, and the adjustment screw 112 is threadedly connected to the adjustment screw sleeve 113, and the end of the adjustment screw 112 can move radially relative to the discharge port 111, and the end of the adjustment screw 112 has a spherical outer surface 1120. The amount of melt flowing through the two discharge ports 111 is ensured to be the same by the up and down movement of the adjustment screw 112.

[0028] Combination Figure 1 and 3As shown, in this embodiment, the melt in the first extrusion flow channel 10 is extruded from the first extrusion flow channel 10, passes through the diversion end plate 12, and is connected to the intermediate flow channel 132 from the second diversion end plate 122; the melt in the second extrusion flow channel 1 comes to the distributor 11, enters the distributor 11 through the distribution inlet 101, and is then distributed to the two discharge ports 111, and the flow rate is adjusted by moving the adjusting screw 112 in the discharge port 111, and the melt divided into two comes from the two discharge ports 111 to the transition flow channels 2 corresponding to each other, and then passes through the second connecting pipe 22 to the first connecting pipe 21. The first connecting tube 21 on the front side is connected to the third diversion end plate 123, and the first connecting tube 21 on the rear side is connected to the first diversion end plate 121. The melt is connected to the outer flow channel 131 through the first diversion end plate 121, and the third diversion end plate 123 connects the melt to the inner flow channel 133. Then, together with the melt flowing into the middle flow channel 132 at the second diversion end plate 122, the three flow out from the spiral body 13, and then are extruded from the melt channel flow formed by the mouth die 14 and the core die 15, thereby forming a tubular product.

[0029] The melt in the second extrusion flow channel 1 is divided into two by the distributor 11 and then passes through the transition flow channel 2. The combination of the ball socket portion 202 of the first connecting tube 21 and the spherical protrusion 201 of the second connecting tube 22 prevents leakage at the joint when the first connecting tube 21 and the second connecting tube 22 are connected. The centers of the spherical protrusion 201 and the ball socket portion 202 are arranged on the same axis, thereby ensuring the consistency of the amount of material reaching the spiral body 13, so that the thickness of the product extruded from the mold is the same, avoiding the wall deviation phenomenon of the pipe product.

[0030] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments, and the above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, and the scope of protection of the present invention is defined by the attached claims, description and their equivalents.

Claims

1. A multi-layer co-extrusion die, comprising a first extrusion flow channel (10) connected to a first main machine, a second extrusion flow channel (1) connected to a second main machine, a distributor (11), a plurality of diversion end plates (12), a spiral (13), a die (14) and a core die (15), wherein the distributor (11) is located between the second extrusion flow channel (1) and the diversion end plate (12), and characterized in that: A pair of transition channels (2) are also provided between the distributor (11) and the plurality of flow dividing end plates (12), the transition channel (2) comprising a first connecting tube (21) connected to the flow dividing end plate (12), and a second connecting tube (22) connected to the first connecting tube (21) via a flange (23); the end of one of the first connecting tube (21) and the second connecting tube (22) comprises a spherical protrusion (201), the end of the other of the first connecting tube (21) and the second connecting tube (22) comprises a socket (202), the spherical protrusion (201) matches the socket (202), and the spherical surface of the spherical protrusion (201) and the spherical socket surface of the socket (202) fall on the center line of the transition channel (2).

2. A multi-layer co-extrusion die according to claim 1, characterized in that: The first connecting pipe (21) is threadedly connected to the flow dividing end plate (12).

3. A multi-layer co-extrusion die according to claim 1, characterized in that: The other end of the second connecting tube (22) opposite to the spherical protrusion (201) or the socket (202) is connected to the distributor (11) via a third component, and a gasket (3) is provided between the distributor (11) and the second connecting tube (22).

4. A multi-layer co-extrusion die according to claim 3, characterized in that: The distributor (11) is provided with a pair of shallow grooves (110), and the gasket (3) and the other end of the second connecting pipe (22) are embedded in the shallow grooves (110).

5. A multi-layer co-extrusion die according to claim 3, characterized in that: The material of the gasket (3) is copper.

6. A multi-layer co-extrusion die according to claim 2, characterized in that: The distributor (11) has two discharge ports (111), and the distributor (11) also has a pair of adjustment screws (112) for adjusting the sizes of the two discharge ports respectively.

7. The mold with spherical flow channel for plastic extrusion according to claim 6, characterized in that: An adjusting screw sleeve (113) is fixedly connected to the outer side of the distributor (11), the adjusting screw (112) is threadedly connected to the adjusting screw sleeve (113), and the end portion of the adjusting screw (112) is capable of moving radially relative to the discharge port (111); the end portion of the adjusting screw (112) has a spherical outer surface (1120).

8. The multi-layer co-extrusion die according to claim 1, characterized in that: The diversion end plate (12) comprises a first diversion end plate (121), a second diversion end plate (122) and a third diversion end plate (123); the spiral body (13) has an outer flow channel (131), an intermediate flow channel (132) and an inner flow channel (133), wherein the first diversion end plate (121) and the third diversion end plate (123) are respectively connected to the outer flow channel (131) and the inner flow channel (133), and a pair of transition flow channels (2) are respectively connected to the distributor (11) and the first diversion end plate (121) and the third diversion end plate (123).

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