Method of cleaning pipes and tubes by pigging using water hammer shock waves

Claim 1

A method of cleaning tubes by pigging which comprises: (1) applying a highly pressurized liquid to one face of a suitably dimensioned, relatively incompressible, solid pig located adjacent one end of said tube locus so as to provide a pressure build-up at said pig which is sufficiently rapid to produce one or more water hammer shock waves which pass down the length of said tube, said pig being dimensioned to conform with the average lumen defined by the thickness of deposits on the tube; and (2) maintaining pressure on said pig for a sufficient time to propel said pig at high velocity through said tube locus to be cleaned, whereby at least portions of said deposits are loosened within said tube by said one or more shock waves and are expelled from said tube by said propelled pig, and (3) if necessary, successively repeating steps (1) and (2) as successive layers of deposits are removed, with pigs of successively larger diameter.

Claim 2

A method of cleaning tubes by pigging which comprises: (1) applying a highly pressurized liquid to one face of a suitably dimensioned, relatively incompressible, solid pig located adjacent one end of said tube locus so as to provide a pressure build-up at said pig which is sufficiently rapid to produce one or more water hammer shock waves which pass down the length of said tube, said pig being dimensioned to conform with the average lumen defined by the thickness of deposits on the tube; and (2) maintaining pressure on said pig for a sufficient time to propel said pig at high velocity through said tube locus to be cleaned, whereby at least portions of said deposits are loosened within said tube by said one or more shock waves and are expelled from said tube by said propelled pig, and (3) if necessary, successively repeating steps (1) and (2) as successive layers of deposits are removed, with pigs of successively larger diameter.

Claim 5

An apparatus for cleaning tubes comprising a high pressure pump; means for creating water hammer shock waves comprising quick-operating valve means connected to said pump and to one or more pressure outlets; one or more launchers, said pressure outlets leading to said one or more launchers and each of said one or more launchers comprising a high pressure connecting means and a launcher tip, said launcher tip engaging the end of a tube to be cleaned and being of such internal diameter that pressure drop within said launcher tip is prevented or minimized whereby liquid may be brought into contact with a pig located in said tube to be cleaned but minor leakage is permitted between said launcher tip and said tube end, and a magazine for pigs associated with each said one or more launchers whereby such pigs may be fed sequentially to each said launcher.

Claim 6

An apparatus for cleaning tubes comprising a high pressure pump; means for creating water hammer shock waves comprising quick-operating valve means connected to said pump and to one or more pressure outlets; one or more launchers, said pressure outlets leading to said one or more launchers and each of said one or more launchers comprising a high pressure connecting means and a launcher tip, said launcher tip engaging the end of a tube to be cleaned and being of such internal diameter that pressure drop within said launcher tip is prevented or minimized whereby liquid may be brought into contact with a pig located in said tube to be cleaned but minor leakage is permitted between said launcher tip and said tube end, and a magazine for pigs associated with each said one or more launchers whereby such pigs may be fed sequentially to each said launcher.