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:
Jan. 07, 2003
Filed:
Aug. 27, 2001
Saul Mirsky, West Des Moines, IA (US);
Compressor Controls Corporation, Des Moines, IA (US);
Abstract
Accurate and effective antisurge control for turbocompressor stages is augmented by measuring the flow rate of fluid entering or leaving the stage of compression. On the other hand, turbocompressors with sidestreams, such as ethylene, propylene, and propane refrigeration compressors, pose unique antisurge control challenges; in particular, measurements for the flow rate entering (or leaving) the compressors' middle stages are not available in most cases. Furthermore, the methods used to cope with this lack of flow measurements are prone to introducing errors and producing false transients, as well as being cumbersome and difficult to implement. For these reasons, this disclosure relates to a method for protecting turbocompressors with sidestreams from the damaging effects of surge. But more specifically, it describes a technique for estimating the reduced flow rate entering a compression stage not having a flow measurement device in its suction or discharge—that is, the flow rate entering a middle (intermediate) compressor stage can be inferred from known flow rates. The reduced flow rate is used to determine a location of the compression stage's operating point relative to its surge limit. The proposed method employs (1) the first law of thermodynamics to estimate the temperature of a flow entering one of the compressor stages, and (2) a relationship between the pressures and temperatures in suction and discharge used in conjunction with the first law of thermodynamics.