A sealing structure for the discharge end of a vacuum sizing box for MPP pipe production

Abstract

The utility model discloses a sealing structure for a discharge end of a vacuum sizing box for producing MPP pipes, comprising at least three flanges of the same structure whose outer diameters decrease sequentially and whose inner diameters decrease sequentially, namely a first flange, a second flange and a third flange; the first flange, the second flange and the third flange are sequentially overlapped and installed at the discharge end of the vacuum sizing box; a first sealing gasket is arranged between the first flange and the side wall of the discharge end of the vacuum sizing box; a second sealing gasket is arranged between the first flange and the second flange; a third sealing gasket is arranged between the second flange and the third flange; a central coaxial through hole is provided at the center of the first sealing gasket, the second sealing gasket and the third sealing gasket. By arranging multiple sealing gaskets, the present application can improve the sealing performance between the flange and the vacuum sizing box and between the flanges on the one hand, and can form multiple seals for the MPP pipes on the other hand; the aperture of each through hole and the ring width of each sealing ring are determined through repeated experiments and calculations, so as to extend the service life of the sealing gasket.

Description

Technical Field

[0001] The utility model relates to the technical field of sealing the discharge end of a vacuum sizing box for producing MPP pipes, in particular to a sealing structure for the discharge end of a vacuum sizing box for producing MPP pipes. Background Art

[0002] Vacuum sizing is an important step in the MPP pipe production process. The principle is that the molten raw materials are squeezed out from the extruder die head into the vacuum sizing box. A vacuum pump is installed outside the vacuum sizing box to evacuate the inside of the vacuum sizing box to prevent atmospheric pressure from exerting pressure on the MPP pipe billet and causing deformation.

[0003] In order to ensure a good vacuum environment in the vacuum sizing box, it is necessary to ensure the sealing effect of the feed end and the discharge end of the vacuum sizing box. The feed end of the vacuum sizing box is connected to the extruder without pressure relief, and the discharge end of the vacuum sizing box is in direct contact with the external environment, so a sealing device needs to be set on the discharge end. The sealing structure of the discharge end currently on the market is as follows: Figure 1 As shown, the first flange (10), the second flange (20) and the third flange (30) are overlapped in sequence and fixedly installed at the discharge end of the vacuum sizing box by bolts 50, wherein a sealing gasket (40) is arranged between the second flange (20) and the third flange (30). In this structure, the contact surface between the sealing gasket (40) and the MPP pipe is small and the sealing performance is poor. Utility Model Content

[0004] The utility model aims to provide a sealing structure for the discharge end of a vacuum sizing box used in the production of MPP pipes.

[0005] The innovation of the utility model lies in that: by setting multiple sealing gaskets, the present application improves the sealing between the flange and the vacuum sizing box, and between the flanges, and on the other hand can form multiple seals for the MPP pipe; through repeated experiments and calculations, the aperture of each perforation and the ring width of each sealing ring are determined, thereby extending the service life of the sealing gasket.

[0006] In order to achieve the above-mentioned utility model purpose, the technical solution of the utility model is:

[0007] A sealing structure for the discharge end of a vacuum sizing box for the production of MPP pipes, comprising at least three flanges of the same structure with successively decreasing outer diameters and inner diameters, namely, a first flange, a second flange, and a third flange; the first flange, the second flange, and the third flange are overlapped in sequence to form a bundle-shaped opening, and are installed at the discharge end of the vacuum sizing box; a first sealing gasket is arranged between the first flange and the side wall of the discharge end of the vacuum sizing box; a second sealing gasket is arranged between the first flange and the second flange; a third sealing gasket is arranged between the second flange and the third flange; coaxial through-holes are respectively provided in the centers of the first sealing gasket, the second sealing gasket, and the third through-hole; the MPP pipe passes through the first through-hole, the second through-hole, and the third through-hole in sequence. Perforation; the apertures of the first perforation, the second perforation and the third perforation are all smaller than the outer diameter of the MPP pipe; the area between the edge of the first perforation on the first sealing gasket and the inner edge of the first flange is the first sealing ring; the area between the edge of the second perforation on the second sealing gasket and the inner edge of the second flange is the second sealing ring; the area between the edge of the third perforation on the third sealing gasket and the inner edge of the third flange is the third sealing ring; the ring widths of the first sealing ring, the second sealing ring and the third sealing ring decrease in sequence, the ring width of the first sealing ring is 35%-40% of the outer diameter of the MPP pipe; the ring width of the second sealing ring is 30%-35% of the outer diameter of the MPP pipe; the ring width of the third sealing ring is 25%-30% of the outer diameter of the MPP pipe.

[0008] Furthermore, the apertures of the first perforation, the second perforation and the third perforation decrease in sequence to form a bundle-mouth shape; the aperture of the first perforation is 10-15 mm smaller than the outer diameter of the MPP pipe; the aperture of the second perforation is 15-25 mm smaller than the outer diameter of the MPP pipe; and the aperture of the third perforation is 25-30 mm smaller than the MPP pipe.

[0009] Furthermore, the thickness of the first sealing gasket, the second sealing gasket and the third sealing gasket is 5-7 mm.

[0010] The beneficial effects of the utility model are:

[0011] First: This application provides multiple sealing gaskets (first sealing gasket, second sealing gasket and third sealing gasket), which, on the one hand, has good sealing between the flanges; on the other hand, the apertures of the first perforation, second perforation and third perforation opened in the center of the first sealing gasket, the second sealing gasket and the third sealing gasket are all smaller than the outer diameter of the MPP pipe, forming multiple surrounds for the MPP pipe and having good sealing.

[0012] Second: The ring width of the first sealing ring is 35%-40% of the outer diameter of the MPP pipe, which can prevent the soft sealing gasket from deforming and being sucked into the vacuum sizing box during the production process.

[0013] Third: The apertures of the first, second and third perforations decrease in sequence, and the aperture of the first perforation is 10-15mm smaller than the outer diameter of the MPP pipe; the aperture of the second perforation is 15-25mm smaller than the outer diameter of the MPP pipe; the aperture of the third perforation is 25-30mm smaller than the MPP pipe; on the basis of ensuring sealing, the wear between the gasket and the MPP pipe can be reduced, the risk of gasket damage during long-term operation is reduced, and the service life of the gasket is extended. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a schematic diagram of the prior art structure.

[0015] Figure 2 This is a schematic structural diagram of the utility model.

[0016] Figure 3 It is a top view of the utility model (bolts are not drawn).

[0017] Figure 4 for Figure 2 Medium AA-directed graph.

[0018] In the figure: 10 is the first flange, 11 is the first sealing gasket, 12 is the first through-hole, 13 is the first sealing ring, 20 is the second flange, 21 is the second sealing gasket, 22 is the second through-hole, 23 is the second sealing ring, 30 is the third flange, 31 is the third sealing gasket, 32 is the third through-hole, 33 is the third sealing ring, 40 is the sealing gasket, and 50 is the bolt. DETAILED DESCRIPTION

[0019] The technical solutions in the embodiments of the present invention will be described clearly and completely below with reference to the accompanying drawings.

[0020] A sealing structure for the discharge end of a vacuum sizing box for MPP pipe production includes at least three flanges of identical structure with successively decreasing outer and inner diameters, namely a first flange 10, a second flange 20, and a third flange 30. The first flange 10, the second flange 20, and the third flange 30 are sequentially overlapped to form a bundled opening and are installed at the discharge end of the vacuum sizing box.

[0021] A first sealing gasket 11 is provided between the first flange 10 and the side wall of the discharge end of the vacuum sizing box; a second sealing gasket 21 is provided between the first flange 10 and the second flange 20; and a third sealing gasket 31 is provided between the second flange 20 and the third flange 30.

[0022] The first sealing gasket 11, the second sealing gasket 21, and the third sealing gasket 31 are provided with coaxial through-holes at their centers, namely the first through-hole 12, the second through-hole 22, and the third through-hole 32. The MPP pipe passes through the first through-hole 12, the second through-hole 22, and the third through-hole 32 in sequence. The diameters of the first through-hole 12, the second through-hole 22, and the third through-hole 32 are all smaller than the outer diameter of the MPP pipe.

[0023] The area between the edge of the first through-hole 12 on the first sealing gasket 11 and the inner edge of the first flange 10 is the first sealing ring 13; the area between the edge of the second through-hole 22 on the second sealing gasket 21 and the inner edge of the second flange 20 is the second sealing ring 23; the area between the edge of the third through-hole 32 on the third sealing gasket 31 and the inner edge of the third flange 30 is the third sealing ring 33; the ring widths of the first sealing ring 13, the second sealing ring 23 and the third sealing ring 33 decrease successively, the ring width of the first sealing ring 13 is 35%-40% of the outer diameter of the MPP pipe; the ring width of the second sealing ring 23 is 30%-35% of the outer diameter of the MPP pipe; the ring width of the third sealing ring 33 is 25%-30% of the outer diameter of the MPP pipe.

[0024] Furthermore, a first sealing gasket 11, a second sealing gasket 21 and a third sealing gasket 31 are provided to strengthen the sealing and shock resistance between the first flange 10 and the side wall of the discharge end of the vacuum sizing box, the first flange 10 and the second flange 20, and the second flange 20 and the third flange 30.

[0025] Furthermore, the apertures of the first through-hole 12 , the second through-hole 22 , and the third through-hole 32 are all smaller than the outer diameter of the MPP pipe. When the MPP pipe passes through the first through-hole 12 , the second through-hole 22 , and the third through-hole 32 in sequence, it is surrounded by multiple holes, forming multiple seals from the inside to the outside.

[0026] Furthermore, since the material of the sealing gasket is soft, in order to prevent the first sealing gasket 11 from being sucked into the vacuum sizing box, after repeated experiments and tests, it was determined that this defect can be overcome when the ring width of the first sealing ring 13 is 35%-40% of the outer diameter of the MPP pipe.

[0027] Furthermore, the apertures of the first perforation 12, the second perforation 22 and the third perforation 32 decrease successively to form a bundle-mouth shape; the aperture of the first perforation 12 is 10-15mm smaller than the outer diameter of the MPP pipe; the aperture of the second perforation 22 is 15-25mm smaller than the outer diameter of the MPP pipe; the aperture of the third perforation 32 is 25-30mm smaller than the MPP pipe; the apertures of the first perforation 12, the second perforation 22 and the third perforation 32 are obtained through repeated experiments and tests. On the basis of ensuring the sealing performance, the wear between the sealing gasket and the MPP pipe can be reduced, and the risk of damage to the sealing gasket during long-term operation is reduced.

[0028] Furthermore, the thickness of the first sealing gasket 11 , the second sealing gasket 21 and the third sealing gasket 31 is 5-7 mm.

[0029] The embodiments described are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

Claims

1. A sealing structure for the discharge end of a vacuum sizing box for MPP pipe production, characterized in that: It comprises at least three flanges of the same structure whose outer diameters decrease successively and whose inner diameters decrease successively, which are respectively a first flange (10), a second flange (20) and a third flange (30); the first flange (10), the second flange (20) and the third flange (30) are overlapped successively to form a bundle shape, and are installed at the discharge end of a vacuum sizing box; A first sealing gasket (11) is arranged between the first flange (10) and the side wall of the discharge end of the vacuum sizing box; a second sealing gasket (21) is arranged between the first flange (10) and the second flange (20); and a third sealing gasket (31) is arranged between the second flange (20) and the third flange (30); The first sealing gasket (11), the second sealing gasket (21) and the third sealing gasket (31) are provided with coaxial central holes, which are respectively the first through hole (12), the second through hole (22) and the third through hole (32); the MPP pipe passes through the first through hole (12), the second through hole (22) and the third through hole (32) in sequence; the diameters of the first through hole (12), the second through hole (22) and the third through hole (32) are all smaller than the outer diameter of the MPP pipe; The area between the edge of the first perforation (12) on the first sealing gasket (11) and the inner edge of the first flange (10) is the first sealing ring (13); the area between the edge of the second perforation (22) on the second sealing gasket (21) and the inner edge of the second flange (20) is the second sealing ring (23); the area between the edge of the third perforation (32) on the third sealing gasket (31) and the inner edge of the third flange (30) is the third sealing ring (33); the ring widths of the first sealing ring (13), the second sealing ring (23) and the third sealing ring (33) decrease in sequence, the ring width of the first sealing ring (13) being 35%-40% of the outer diameter of the MPP pipe; the ring width of the second sealing ring (23) being 30%-35% of the outer diameter of the MPP pipe; and the ring width of the third sealing ring (33) being 25%-30% of the outer diameter of the MPP pipe.

2. The sealing structure of the discharge end of a vacuum sizing box for MPP pipe production according to claim 1, characterized in that: The apertures of the first perforation (12), the second perforation (22) and the third perforation (32) decrease in sequence to form a bundle-shaped opening; the aperture of the first perforation (12) is 10-15 mm smaller than the outer diameter of the MPP pipe; the aperture of the second perforation (22) is 15-25 mm smaller than the outer diameter of the MPP pipe; and the aperture of the third perforation (32) is 25-30 mm smaller than the MPP pipe.

3. The sealing structure of the discharge end of a vacuum sizing box for MPP pipe production according to claim 1, characterized in that: The thickness of the first sealing gasket (11), the second sealing gasket (21) and the third sealing gasket (31) is 5-7 mm.

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