Locking and sealing device for blow molding of plastic pipeline

Abstract

The invention discloses a locking and sealing device for blow molding of a plastic pipeline. The device comprises a forming mold cylinder and an inflation mandrel penetrating through the forming mold cylinder; a convex ring is fixedly arranged on the inner circumference of the forming die cylinder, a plurality of radial stepped holes are formed in the forming die cylinder on the axial inner side of the convex ring, a special-shaped steel ball with steps is arranged in each step in a sliding mode, and a reset spring is arranged outside each special-shaped steel ball; a sealing nest is arranged on the inflation mandrel in a sliding mode, and an annular cutter is fixedly arranged on the axial inner side of the sealing nest; and a clamping push cylinder is sleeved outside the special-shaped steel ball, outside the outer end of the forming die cylinder and outside the sealing nesting sleeve, the clamping push cylinder is fixedly connected with a radial push plate, and the inner circumference of the clamping push cylinder is provided with an initial cylindrical surface, a contraction conical surface and a locking cylindrical surface which are connected in sequence. The device is good in locking effect and easy to demold, the sealing effect of thermoplastic plastic in a viscous flow state under high pressure is guaranteed, and the forming quality and efficiency can be improved.

Description

technical field [0001] The invention relates to a plastic pipe blow molding locking and sealing device, in particular to a PVC-O pipe blow molding locking and sealing device. Background technique [0002] PVC-O biaxially oriented polyvinyl chloride is the latest evolutionary form of PVC pipes. It will use the extrusion method to produce PVC-U pipes for axial stretching and radial stretching, so that the PVC long chains in the pipes The molecules are arranged biaxially and regularly. Through this special orientation processing technology, new PVC pipes with high strength, high toughness, high impact resistance and fatigue resistance can be obtained. [0003] At present, the new production method of PVC-O pipe has two-step processing method. The two-step processing method is to expand the extruded and cooled PVC-U pipe section (thick blank) to the required size by heating and blow molding in the mold. to achieve orientation. The two-step pipe production has its own unique pr...

AI Technical Summary

Problems solved by technology

The two-step pipe production has its own unique pressure forming method, which requires locking and sealing of the hot blank tube in the mold, and since the blank tube is in a thermoplastic state at this time, locking the blank tube can be easily done , but it is difficult to seal viscous thermoplastics. For example, the U.S. patent with the publication number US2011163489A1 discloses a locking device for the production of two-step PVC-O pipes from Molecor, Spain. This device includes the aforementioned The operation of locking the hot blank tube is mainly composed of locking both ends of the thermoplastic blank tube, in which the fixed end adopts the external locking method, and the moving end adopts the internal locking method; two kinds of locking The method is to use a specific track to cooperate with the steel ball, and the radial movement of the steel ball is achieved by axial movement to achieve locking; this patent can effectively solve the locking problem of the thermoplastic blank tube, but it does not mention the sealing of the blank tube; In addition, the steel ball locking method adopted in this patent does not take into account the problem that the steel ball is not reset after being embedded in the blank tube, which leads to the problem that the blank tube cannot be demolded smoothly; the patent with the domestic publication number CN208565938U discloses a pipe locking and sealing device , the patent relates to the field of pipeline locking and sealing, and its specific implementation is to force the rubber sealing sleeve to deform radially through the axial movement of the inner cone nest to form an interference and clearance fit with the pipeline to achieve locking and sealing and release As a result, the patent provides a locking and sealing method for hard pipes, which can work when the internal pressure of the pipe is low, and solve the problem of locking and sealing hard pipes, but it is fundamentally different from the locking and sealing of plasticized plastic pipes, so it cannot be applied in high pressure conditions

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