The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jul. 13, 2004
Filed:
May. 24, 2001
Gary Don Ellis, Proctorville, OH (US);
Matthew T. Lusher, Ona, WV (US);
BASF Corporation, Southfield, MI (US);
Abstract
A composition and method for the removal of scale from a substrate are disclosed. The composition and method are more specifically utilized for the in situ removal of silicate-containing scale from interior surfaces of boilers and other heat exchange equipment. The silicate-containing scale is deposited in the boilers as silicate-sulfate complexes of calcium, magnesium, aluminum, and other metal atoms that are present in water. The composition, which is circulated throughout the boiler to contact the interior surfaces, such as the boiler tubes, includes a chelating agent having at least two carboxylic acid functional groups, preferably citric acid. The composition also includes an alkali metal hydroxide basic agent. The preferred alkali metal hydroxides are either potassium or sodium hydroxide. The basic agent establishes an overall basic pH of from 7 to 14 in the composition to enable precipitation of the metal atoms from the composition after interaction with the chelating agent.