Method of cleaning a pipe with a cylindrical pipe pig having pins in the central portion

Abstract

A pipe pig is reciprocated through a section of a pipe having deposits of scale. In the case of very hard deposits, each pass through the contaminated sections removes a thin layer each time. The location of the coated section can be located by first running the pig through the pipe. The hydraulic pressure is monitored using pen recorders. At each bend in the pipe, a sharp pressure increase will be recorded. The location of the bends can be determined from a drawing of the pipe installation. When the pig encounters scale, there will be a pressure increase that corresponds to the degree of resistance met by the pig resulting from the scale. Greater pressure means greater scale build up. By running the pig through the pipe, a profile of the scale may be created. The location of the scale can be correlated to the known location of the bends. The scale itself can be flushed out with the hydraulic propellant and analyzed. The pin height and hardness can then be selected for the particular scale encountered. The pig may be run backwards and forwards primarily through the contaminated section. After several passes, the pig can be removed from the pipe, the pins replaced or moved radially outward by placing washers between at least some of the pins and the pig body and the pig returned to the pipe.

Dependencies are inferred from the claim text.