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. 03, 2001
Filed:
Sep. 03, 1999
Mitsubishi Heavy Industries, Ltd., Tokyo, JP;
Abstract
Stress occurring in a moving blade in a gas turbine stopping process is decreased. Time t,is load decrease start or fuel throttling start, time t,is no load operation start, time t,is fuel shut-off and time t,is a time of largest stress. A 4/4 load maintained until t,decreases gradually to a 0/4 load at t,, which is then maintained until t,and then decreases further. The rotational speed is the rated speed until t,, at which point it is controlled to be decreased gradually to about 60% of the rated rotational speed at t,. The metal differential temperature between a moving blade point A and a platform point B is constant until t,and is then decreased slightly between t,and t,and between t,and t,. Differential temperature &Dgr;t, largest after t,, occurs at t,. Stress occurring in the moving blade, while decreasing between t,and t,, becomes largest at t,by the effect of centrifugal force and thermal stress, but as the rotational speed is decreased to about 60% of the rated rotational speed at t,and the metal temperature is also decreased as compared with the prior art, the influence of the centrifugal force and the differential temperature is decreased, whereby stress occurring in the moving blade is mitigated.