Contiguous event discrimination in electrostatic engine diagnostics

• US 4,595,987 A
• Filed: 12/28/1982
• Issued: 06/17/1986
• Est. Priority Date: 12/28/1982
• Status: Expired due to Term

• Current Assignee: United Technologies Corporation (Raytheon Technologies Corporation d/b/a RTX)
• Original Assignee: United Technologies Corporation (Raytheon Technologies Corporation d/b/a RTX)
• Inventors: Rosenbush, David M., Zwicke, Philip E., Couch, Robert P.
• Primary Examiner(s): Chin, Gary
• Application Number:
  US06/454,118
• Time in Patent Office: 1,267 Days
• Field of Search: 364/431.01, 364/431.02, 364/179, 364/424, 364/551, 364/552, 364/506-508, 324/379, 324/464, 73/116, 73/117.3, 340/627, 340/683
• US Class Current: 701/100
• CPC Class Codes: G07C 3/00 Registering or indicating the condition or the working of machines or other apparatus, other than vehicles

Abstract

The waveforms (FIGS. 57-80) of signals produced by electrostatic probes (1, 2, 3, FIG. 1) are established in records (FIGS. 5 and 6) about 80 milliseconds long; if successive records are sensed contiguously (into N, without any break in-between) the first record of a string is provided with a flag indicative thereof (FIG. 8a) and the second and last records in the contiguous string are stored in special buffers (FIGS. 8b and 8c). All of the other records in-between are thrown away. The string of contiguous records are treated specially: the three records have their characteristics combined in identifying acceleration/deceleration (FIG. 80) and peeled off abraidable seals (FIGS. 62 , FIG. 45c); only the first record is utilized to identify the start of an afterburner chop (FIGS. 77 and 54a) and only the last record is utilized to identify the end of a chop (FIGS. 78, 79 and 54a).

Claims

1. Electrostatic diagnostic apparatus for distinctly correlating different events occurring in an operating gas turbine engine, comprising:

electrostatic signal means, including a probe to be disposed in the gas stream of an engine, for providing, when said probe is disposed in the gas stream of an operating engine, a probe signal having a waveshape defined by amplitude variations thereof across a time interval of a given duration in response to electrostatic charge flowing in the gas stream in the vicinity of said probe;

an analog to digital converter connected for response to said electrostatic signal means; and

signal processing means connected to said analog to digital converter

(a) for causing said analog to digital converter to sample the probe signal provided by said electrostatic signal means in a manner to provide a record of digital signals indicative of the amplitude variations thereof defining the waveshape thereof,

(b) for storing, in response to the amplitude of one of said digital signals being in excess of a threshold magnltude, a record comprising a contiguous sequence of said digital signals sufficient to define the waveshape of said probe signal, repetitively, to provide a classification group consisting of a given number of said records,

(c) for providing a contiguous signal based on a plurality of records in said group each containing one of said digital signals which are contiguous to one of said digital signals contained in another one of said records,

(d) for classifying said records in accordance with characteristics of the waveshapes thereof individually in the case of records not identified as contiguous by said contiguous signal, and

(e) for classifying said plurality of records identified as contiguous by said contiguous signal as an individual record in accordance with characteristics of the waveshapes thereof.

2. Electrostatic diagnostic apparatus for distinctly correlating different events occuring in an operating gas turbine engine, comprising:

electrostatic signal means, including a probe to be disposed in the gas stream of an engine, for providing, when said probe is disposed in the gas stream of an operating engine, a probe signal having a waveshape defined by amplitude variations thereof across a time interval of a given duration in response to electrostatic charge flowing in the gas stream in the vicinity of said probe;

an analog to digital converter connected for response to said electrostatic signal means; and

signal processing means connected to said analog to digital converter

(a) for causing said analog to digital converter to sample the probe signal provided by said electrostatic signal means in a manner to provide a record of digital signals indicative of the amplitude variations therein defining the waveshape thereof,

(b) for storing in a history buffer a contiguous sequence of said digital signals, said sequence containing at least a first number of said signals,

(c) for storing in a record buffer, in response to the amplitude of one of said digital signals being in excess of a threshold magnitude, a record comprising

(1) said first number of said digital signals stored in said history buffer imediately preceding the one of said digital signals which is in excess of said threshold magnitude and

(2) a contiguous sequence of said digital signals sufficient to define the waveshape of said probe signal,

(d) for counting the number of said digital signals which occur between successive ones of said digital signals which are in excess of said threshold magnitude,

(e) for providing a contiguous signal in the event that the number of said digital signals occurring between successive digital signals in excess of said threshold magnitude is equal to or less than said first number,

(f) for classifying, in accordance with characteristics of the waveshapes thereof, said records singly in the event that said records are not identified as contiguous by said contiguous signal, and

(g) for classifying a plurality of said records as a single record in the event that said contiguous signal identifies said records as being contiguous.