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:
Oct. 03, 2000
Filed:
Dec. 10, 1997
Zenon Environmental Inc., Burlington, CA;
Abstract
An adaptive control method for producing high purity water, the method having the ability to produce high purity water on a continuous basis having a resistivity in the range of 0.8 to 4 megohm-cm. The method comprises the steps of providing a feedwater to be purified and providing a first reverse osmosis unit having a first high pressure side and a first low pressure side and having a first permeate produced at the first low pressure side. The pH of the feedwater to be introduced to the high pressure of the first reverse osmosis unit is monitored before introducing the feedwater to the high pressure side of the first reverse osmosis unit. Also, the feedwater is maintained in a temperature range of 45.degree. to 80.degree. F. A second reverse osmosis unit is provided having a second high pressure side and a second low pressure side for producing high purity product water. The first permeate from the first reverse osmosis unit is passed to the high pressure side of the second reverse osmosis unit and the resistance of the product water produced at the second low pressure side of the second reverse osmosis unit is measured to provide a resistance measurement. The resistance measurement is relayed to a programmable logic controller where it is compared to previous resistance measurements to provide a comparison. In response to the comparison, the pH of the feed water is either maintained or is changed upwardly or downwardly to produce high purity water having the desired resistivity.