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:
Nov. 19, 1991
Filed:
Jul. 12, 1990
James K Hayes, Chattanooga, TN (US);
Combustion Engineering, Inc., Windsor, CT (US);
Abstract
Valve leakage is quantified by measuring a variable that is commensurate with a heat transfer characteristic of the pipe wall (30) and comparing the measurements to data stored in a database (84) which embodies a quantitive relationship between an index commensurate with the heat transfer characteristic variable and a range of valve leakage rates that could occur for the given valve. In a straight forward implementation of the invention, a thermal hydraulic analysis of the specific valve and associated piping are performed a priori to establish a database of pipe wall temperature downstream of the valve as a function of steam flow rate. The wall temperature is simply measured and compared with the database. In another embodiment, an air cooled sleeve (54) is installed around the pipe (48) downstream of the valve (50) and a controlled flow of air is passed through the annulus (62) between the pipe and the sleeve. The temperature rise of the flowing air is measured and is used to compute the flow rate of steam leaking through the valve. In yet another embodiment, the valve leakage is quantified by controlling heat input into a local section of a horizontal pipe (94) upstream of the valve. The measured relation between heater power and pipe wall temperature is used with a database to provide a quantitative relationship between power input or temperature and steam flow through the valve.