PVC-O pipe processing device

Abstract

The utility model discloses a PVC-O pipe processing device, and aims to provide a PVC-O pipe processing device which can reduce the influence of air in a processing place on a plastic pipe blank in the forming process, so that the temperature of the plastic pipe blank is constant and uniform, and the wall thickness of the expanded pipe blank is consistent. The mold comprises a mold, a mold cover, a piston, a sheath, a sealing cover and an ejector sleeve, a stepped hole is formed in the center of the piston, a plurality of protruding blocks are arranged on the inner circle wall of the sheath, and the sealing cover is a plate with a stepped hole in the center. Wherein the main function of the sheath is to stabilize the temperature of the pipe blank in the heating process of the plastic pipe blank in the drying oven and the process of leaving the drying oven and entering the mold after heating, so that the quality of a plastic pipe finished product is obviously improved.

Description

Technical Field

[0001] The utility model relates to the technical field of plastic pipe processing, in particular to a PVC-O pipe processing device. Background Art

[0002] By subjecting the PVC-U pipe produced by the extrusion method (PVC-U pipe is referred to as: pipe blank) to axial stretching and radial stretching, high-strength, high-toughness, high-impact resistance and fatigue-resistant PVC-O pipe can be obtained. It not only greatly saves raw material resources and reduces costs, but also has the advantages of light weight, easy handling and laying, etc. The superb performance enables it to be used in higher pressures and harsher environments.

[0003] The commonly used processing technology of PVC-O pipes at present is to put the extruded and cooled tube into an oven and heat it to the softening point temperature before moving it into the mold. After pressurizing the tube, it is gradually expanded from one end to the other end or the tube is expanded as a whole at the same time to obtain the finished product. The equipment and process are relatively simple, the elongation rate of the tube is high, it is easy to obtain excellent mechanical properties, the finished product specification range is wide, and the socket can be made at the same time.

[0004] Although the above processing technology has many advantages, the uniformity of the overall temperature of the tube is still an important factor that is difficult to control. The time interval between taking the tube out of the oven and moving it into the mold is easily affected by the air flow in the processing area, making it difficult to uniformly heat the tube, resulting in different expansion degrees and inconsistent thicknesses, which affects the mechanical properties of the finished product. Utility Model Content

[0005] The utility model aims to solve the above problems and provide a PVC-O pipe processing device to reduce the influence of air flow in the processing site on the plastic pipe blank during the expansion forming process, make its temperature uniform and stable, and thus make the wall thickness of the pipe blank after expansion forming more consistent.

[0006] In order to achieve the above-mentioned purpose, the utility model PVC-O pipe processing device comprises: a mold, a mold cover, a piston, a sheath, a sealing cover and a push tube, the center of the piston is provided with a stepped hole, the large hole diameter of the stepped hole is adapted to the outer diameter of the sheath, the small hole is adapted to the outer diameter of the tube blank, an annular groove is provided on the inner circular wall of the large hole, a sealing ring is installed in the groove, a plurality of protrusions are provided on the inner circular wall of the sheath, and the sealing cover is a plate with a stepped hole in the center.

[0007] The convex blocks on the inner circular wall of the sleeve have the same height and are hemispherical. A flange is provided at one end of the push tube. The cover is a disc, the large hole of the central stepped hole of which is adapted to the outer diameter of the sleeve, and the small hole is adapted to the outer diameter of the push tube. Annular grooves are provided on the inner circular walls of the large hole and the small hole, respectively, and sealing rings are installed in the grooves.

[0008] By adopting the device of the utility model, the processed tube blank can be heated evenly and the temperature is not easily disturbed by the air flow in the workplace, the temperature is kept relatively stable and even, and the wall thickness of the expanded tube blank is consistent. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] The terms "upper", "lower", "left", "right" and the like used in the present invention are only used to indicate relative positional relationships.

[0010] The processing device of the utility model is further described below in conjunction with the accompanying drawings and embodiments.

[0011] Figure 1 It is a longitudinal sectional view of the processing device of the utility model.

[0012] Figures 2 to 6 It is a schematic diagram of the five main steps of the processing device of the utility model during operation.

[0013] In the figure: 1. mold; 11. inner tube; 2. mold cover; 21. air inlet; 3. piston; 31. sealing ring; 4. tube blank; 5. sheath; 51. bump; 6. push tube; 61. exhaust port; 7. cover; 71. sealing ring; 72. sealing ring. DETAILED DESCRIPTION

[0014] The structure of the processing device of the utility model is as follows Figure 1 As shown, it is composed of a mold 1, a mold cover 2, a piston 3, a sealing ring 31, a sleeve 5, a push tube 6, a sealing cover 7, a sealing ring 71 and a sealing ring 72.

[0015] The outer shell of the mold 1 and the inner cylinder 11 thereon form a cavity, and the outer shell surface has a water inlet and a water outlet. The cooling water of the water supply system flows through the water inlet, the cavity, the water outlet and returns to the water supply system for continuous circulation to cool the mold 1.

[0016] The inner wall of the mold cover 2 is bowl-shaped and can be connected or separated from the mold 1 according to the processing requirements. A circular groove is provided at the center of the inner wall of the mold cover 2, and an air inlet 21 is provided at the center. On the left end surface of the mold cover 2, several grooves (not shown in the figure) extending from the center to the outer circumference are provided to facilitate the discharge of the peripheral gas when the right end of the tube blank 4 expands, so as to avoid resistance to the expansion of the tube blank 4.

[0017] The piston 3 is arranged in the inner cylinder 11 of the mold 1 and is in sliding contact with the inner cylinder 11. The right end face of the piston 3 is an inner conical surface, and the center is a stepped hole. The inner diameter of the large hole is adapted to the outer diameter of the sleeve 5. An annular groove is arranged on the inner circular wall of the hole to accommodate the sealing ring 31, and the inner diameter of the small hole is adapted to the outer diameter of the tube blank 4.

[0018] On the inner wall of the jacket 5, there are several hemispherical bumps 51 of equal height. The purpose of the bumps 51 is to reduce the contact area between the tube blank 4 and the jacket 5 and to leave a gap between the outer circle of the tube blank 4 and the inner circle of the jacket 5, so as to avoid the lower part of the tube blank 4 being too close to the jacket 5 and causing a temperature difference. The jacket 5, which can be separated from or in contact with the piston 4, mainly functions to carry the tube blank 4 in the oven for heating or to shield the influence of the ambient air on the temperature uniformity of the tube blank 4 during the time interval from the oven to the inner cylinder 11 and to supplement the heat lost by the tube blank 4.

[0019] The outer diameter of the flange of the push tube 6 is smaller than the outer diameter of the tube blank 4 and larger than the inner diameter of the tube blank, so as to smoothly push the tube blank 4.

[0020] The cover 7 may be disc-shaped, with the large hole of the central stepped hole adapted to the outer diameter of the sheath 5, and the small hole adapted to the outer diameter of the push tube 6. An annular groove is provided on the inner circular wall of the large hole to accommodate the sealing ring 72, and an annular groove is provided on the inner circular wall of the small hole to accommodate the sealing ring 71. The sealing rings of the two grooves serve to seal the left end of the sheath 5 when the tube blank 4 is pressurized to prevent leakage of the pressurized gas.

[0021] The operation process of the processing device of the utility model is as follows:

[0022] See Figure 2 , the axes of the push tube 5, the cover 7, the inner tube 11 and the mold cover 2 coincide. The left end of the mold cover 2 contacts and locks with the right end surface of the mold 1 (the position of the mold 1 is always fixed). The sheath 5 and the tube blank 4 inside, which are heated to the molecular orientation temperature in the oven, are located between the right end of the push tube 6 and the left end of the mold 1, and their axes coincide with the inner tube 11.

[0023] See Figure 3 The power device (not shown) drives the sealing cover 7 and the push tube 6 to move rightward, successively contacts and drives the sleeve 5 and the piston 3 to move rightward together, and stops when the piston 3 reaches a predetermined distance from the right end of the mold cylinder 11, locks the sealing cover 7 and the sleeve 5, and the push tube 6 continues to move rightward, contacts the tube blank 4 and pushes it to move rightward, and stops when the right end face of the tube blank 4 contacts the bottom of the circular groove of the mold cover 2.

[0024] See Figure 4 , the push tube 6 is moved to the left by the power device until the flange on it contacts the cover 7, stops and is locked, and the exhaust port 61 is closed. The cover 7, the push tube 6, the sealing ring 71, and the sealing ring 72 seal the left end of the sheath 5. The hot pressure gas introduced into the air inlet 21 fills the inner cavity of the tube blank 4 and the sheath 5. Since the inner cavity of the tube blank 4 is connected with the inner cavity of the sheath 5 and the air pressure is the same, the part of the tube blank 4 covered by the sheath 5 will not expand. In a part of the right end of the tube blank 4, since the outside of the tube blank 4 is atmospheric pressure and the inside is hot pressure gas, the tube blank 4 that has been softened after heating will expand radially to form bubbles.

[0025] See Figure 5 , unlock the cover 7, push tube 6, and sleeve 5, and the power device moves the cover 7, push tube 6, and sleeve 5 to the left, and the length range covering the tube blank 4 is gradually reduced. After the bubble gradually extends to the left to a predetermined shape, the air inlet 21 stops introducing hot pressure gas and instead introduces cold pressure gas. The inner wall of the expanded tube blank 4 is cooled by the cold pressure gas and the outer wall is cooled by the cooling water of the inner tube 11 to be shaped.

[0026] See Figure 6 The air inlet 21 is closed, the exhaust port 61 exhausts the cold pressure gas in the tube blank 4 after the shaping, and the power device moves each component (except the cover 7) to the following positions: Figure 2 The expanded, cooled and shaped tube blank 4 is removed from the mold 1 by the power device, and the cover 7 is returned to the position shown in FIG. Figure 2 The position shown in the figure is used for the next working cycle.

Claims

1. A PVC-O pipe processing device, comprising: A mold (1), a mold cover (2), a piston (3), a sleeve (5), a cover (7) and a push tube (6), characterized in that a stepped hole is arranged at the center of the piston (3), the large hole diameter of the stepped hole is adapted to the outer diameter of the sleeve (5), the small hole is adapted to the outer diameter of the tube blank (4), an annular groove is arranged on the inner circular wall of the large hole, a sealing ring (31) is arranged in the groove, a plurality of protrusions are arranged on the inner circular wall of the sleeve (5), and the cover (7) is a plate with a stepped hole at the center.

2. The processing device according to claim 1, characterized in that: The convex blocks on the inner circular wall of the sheath (5) have the same height and are hemispherical.

3. The processing device according to claim 1 is characterized in that One end of the push tube (6) is provided with a flange.

4. The processing device according to claim 1, characterized in that The sealing cover (7) is a circular disk, the large hole of the central stepped hole of which is adapted to the outer diameter of the sleeve (5), and the small hole is adapted to the outer diameter of the push tube (6). Annular grooves are respectively arranged on the inner circular walls of the large hole and the small hole, a sealing ring (71) is arranged in the small annular groove, and a sealing ring (72) is arranged in the large annular groove.

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