Data processing: measuring – calibrating – or testing – Measurement system in a specific environment – Mechanical measurement system
Reexamination Certificate
1998-05-15
2001-12-11
Hoff, Marc S. (Department: 2857)
Data processing: measuring, calibrating, or testing
Measurement system in a specific environment
Mechanical measurement system
C702S033000, C073S570000, C073S593000, C073S597000
Reexamination Certificate
active
06330515
ABSTRACT:
This application claims priority under 35 U.S.C. §§119 and/or 365 to No. 197 21 364.2 filed in Germany on May 22, 1997; the entire content of which is hereby incorporated by reference.
BACKGROUND OF THE INVENTION
1. Field of the invention
The invention relates to a method for initiating protective measures on rapidly running rotary machines upon the occurrence of impermissible vibrations, the vibrations or values derived therefrom essentially being measured as measured variables at the bearings of the rotors.
2. Discussion of Background
In known methods for protecting rapidly running rotary machines in which impermissible vibrations can occur which can destroy the installation, the result being the need to change the operating state as required or in a plannable fashion by means of monitoring signals, the vibration amplitudes or their maximum value are mostly measured in the region of the rotor bearings and compared with prescribed limits for alarm measures or emergency measures. If these limit values are exceeded, monitoring signals are generated as a function of these limit values which set the installation to a different rotational speed, for example, or shut it down completely. In this case, the measuring points can be arranged at a plurality of different sites in the installation, and the data can be processed at the same time. Thus, it is also possible to make use for evaluation of only two of three measured data.
Depending on the particular features and the frequently changing environmental conditions of the installation, however, the limit values fixed in advance can be inappropriate and set off false alarms. Such false alarms, in particular when they are associated with emergency shutdowns, cause a very substantial outlay on restarting and other additional costs, which should be avoided as far as possible. In particular, these limit values cannot be fixed uniquely for technical reasons alone, since, for example, they depend on the duration of a specific operating state, for example the start up state, the degree of warming, generally connected thereto, etc., and fluctuate strongly in many cases. Taking account also of measured data which change in such a way involves a high outlay on equipment and processing, and the aim is to make the monitoring as simple as possible. In particular, because the monitoring units can also fail or must be provided in a fashion which is fail-safe or redundant. Moreover, almost all disturbances which require a protective shutdown caused by vibrations occur suddenly. For this reason, a temporary increase in the limit values in the case of such transitional operating states poses a high risk to the installation. For example, if a blade breakage occurred on a turbo-machine precisely in such a phase, the machine might not shutdown, and further, secondary damage could be entailed.
SUMMARY OF THE INVENTION
Accordingly, one object of the invention is to provide a novel method in which it is possible reliably to distinguish between faulty states of the machine and alternating actions caused by operation, in particular by vibrations or the like in an attempt to avoid the above disadvantages.
This object is achieved according to the invention in that in as first, relatively long time interval a number of measured data of this measured variable are recorded and conditioned using an equalizing function, in that in a second, relatively short time interval, which is located inside the relatively long time interval, current measured data of the same measured variable are recorded and compared with the conditioned measured data of the relatively long time interval, and in that depending on the result of the comparison a monitoring signal corresponding to said result is triggered.
The particular advantage of the invention is to be seen in that the protective actions are automatically initiated when rapid changes occur in the vibration values. The measure permits changes to be detected within second or even fractions thereof. The protective actions themselves can be performed in stages, it being the case that depending on the level of the limit value reached, actions are triggered with increasing effectiveness, for example, firstly raising the alarm, thereafter process-specific action, power reduction and, finally, emergency shutdown. Although the invention does not aim to detect long-term trends, or to set absolute limit values for the vibration amplitudes, these measures can advantageously be combined with the invention. The abovementioned limit values can thus be set somewhat higher than previously, as a result of which unnecessary protective initiations can be avoided in certain circumstances.
Further features and advantages follow from the further claims and from the description of an exemplary embodiment.
REFERENCES:
patent: 4377284 (1983-03-01), Saito et al.
patent: 4408294 (1983-10-01), Imam
patent: 4453407 (1984-06-01), Sato et al.
patent: 4643023 (1987-02-01), Capps
patent: 5018342 (1991-05-01), McClure et al.
patent: 37 25 123 (1988-04-01), None
patent: 37 04 597 (1988-08-01), None
patent: 38 12 474 (1988-11-01), None
patent: 39 29 792 (1990-03-01), None
patent: 40 20 119 (1991-02-01), None
patent: 41 07 575 (1991-11-01), None
patent: 40 29 616 (1992-03-01), None
patent: 44 06 723 (1994-09-01), None
patent: 295 13 754 U (1995-12-01), None
patent: 195 48 279 (1997-04-01), None
patent: 196 25 947 (1997-09-01), None
patent: 0 355 255 (1990-02-01), None
patent: 0 536 451 A1 (1993-04-01), None
patent: 2 225 163 (1990-05-01), None
Alstom
Burns Doane Swecker & Mathis L.L.P
Hoff Marc S.
Vo Hien
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