| 摘要 |
A method of forming a pipeline pig in two or more steps is provided. Selected disks and/or cups, of selected size and hardness, are first formed. These disks and/or cups may include scraper disks, seal disks, flower petal disks, and/or cups in various sizes and hardnesses, in any desired permutation of these characteristics. The preformed pig components are then arranged with a plurality of mold pieces placed between the various disks and/or cups and then a second molding step is performed. The pig components which are formed in the first step preferably include a large central hole through which polyurethane will flow in the second molding step to form the mandrel. The pig components also preferably include a plurality of smaller holes radially spaced around the large central hole. The smaller holes serve to form a mechanically robust coupling between the pre-formed pig components and the polyurethane mandrel. Thus, the various pig components may be combined in any desired permutation of characteristics, so that a pig with desired working properties may be tailored to a specific task.
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