1. Field of the Invention
The present invention concerns protective devices for pipes that have threading.
2. Background of the Invention
Pipes, particularly pipes for oil fields, are often exposed to various climatic conditions when transported and stored. As a result pipes tend to corrode, primarily on their inside. Usually pipes with threading are provided with protective caps to protect the threads. Also, in order to prevent foreign bodies and rain water from reaching the interior of the pipes, closed or sealed protective caps and protective plugs are often used. But these caps and plugs result in the formation of condensed water due to variations in temperature. This water enhances the formation of rust.
Chemical agents that absorb moisture from their surroundings are well known in the prior art. Such agents are generally known as dessicants or drying agents. It is also known that in order to protect pipes from rust, dessicants may be packed in bags and inserted just inside the ends of pipes. These known protective devices do not suffice to protect pipes from the formation of rust, however. The moisture in pipes, particularly those of considerable length, is only absorbed by the dessicant that is in the immediate vicinity of the moisture. Thus, the inner pipe surfaces may rust despite the dessicant at the ends of the pipe. Thus with prior protective devices it is necessary to inspect the pipes from time to time by removing the protective caps and protective plugs. This visual inspection is quite cumbersome, time-consuming, and expensive.