Showing papers on "Condition monitoring published in 1975"

Condition monitoring by sound analysis

Abstract: Noises from machinery can be environmentally undesirable and in need of suppression. Yet the sounds produced by a machine result from the dynamics of its components and by regularly monitoring these sounds such changes as occur can be used to diagnose the condition of the machine and the possible onset of faults and failure. A further extension of such sound monitoring is the possible use of acoustic emissions as a means of determining production efficiency and product quality.

Method and apparatus for extending the operating range of a condition monitoring system

Abstract: Apparatus and method for extending the operating range of a condition monitoring system that detects the occurrence of an abnormal condition on a first member moving relative to a second member; the system including a sensor circuit on the first member adapted to be responsive to the condition being monitored and a monitoring circuit on the second member adapted to being affected by the proximate presence of a close-circuited sensor circuit to provide detection signals to circuit means for indicating the condition of the moving member indicative of the open or close-circuited sensor circuit. The system is characterized by a monitoring circuit operating at the threshold of an oscillatory and nonoscillatory state and a close-circuited sensor circuit configuration that affects the monitoring circuit irrespective of its operational state.

Microprocessor Application on Board Ships

Abstract: Through participation in several research projects concerned with the application of computers on board ships, the R & D department in Det norske Veritas has played a major part in the development of 4 different types of microprocessor units suitable for installation on board ships. These are: Condition monitoring unit for diesel engines; condition monitoring unit for mechanical conditions in steam power plants; condition monitoring unit for thermodynamic conditions in steam power plants; and condition monitoring unit for dynamic loads in the ships' hull. All four units may generally be classified as minicomputer replacements. The applications are presented with a description of history, function, type of sensors, complexity of hardware/software, and experience obtained. Future aspects of microprocessor applications on board ships will also be discussed

Availability of a System Subject to Irregular Short Supervision

Abstract: The availability is analysed for a supervised system which has very short and arbitrarily distributed supervisory periods (supervision is a continuous monitoring to detect failures). The Markov model is continuous in time and alternates between two and three discrete states; it leads to an expression which can be used in an iterative calculation of availability. Optimisation of availability is used to illustrate the approach.

Diagnostics and Engine Condition Monitoring.

Abstract: : These proceedings consist of the 23 papers prepared for the PEP 43rd Specialists Meeting on Diagnostics and Engine Condition Monitoring held at Liege, Belgium, and the discussions which took place at the meeting site as a result of the advance exchange of these papers. On the two days of 4 and 5 April sessions were conducted on economics, statistics, and function of ECM; implementation of ECM; instrumentation; and computers, fault logic, and displays.

Optimal Control of Unreliable Dynamic Systems with Discrete Time Inspections

Abstract: The optimal control of unreliable dynamic systems where the mode (working or failed) is continuously inspected or monitored has received attention in the past. We consider the problem where instead of continuous inspection we have either no inspection or inspection at discrete time instants. The optimal feedback control is derived for the case where the system has no renewable capabilities. The case where a fixed number of renewals are allowed is briefly discussed.

Practical condition monitoring of rotating machinery by vibration analysis

Abstract: This paper deals with vibration analysis as a method for condition monitoring of rotating machinery. Vibration characteristics and methods for vibration analysis are briefly discussed. Based upon experience from project ships, some examples of typical machine damage and their corresponding vibration signatures are shown and commented. The paper concludes with a proposal for a vibration monitoring system and suitable instrumentation.

User experience with computerized machinery vibration analysis

Abstract: Real-time frequency analyzers (RTAs) are extending the gains made toward improved machinery reliabilty through application of advanced vibration technology to high-speed, high capacity turbomachinery trains found in modern refineries and chemical plants. This article discusses an automated system for data analysis and maintenance of historical records in a dedicated minicomputer system for a periodic condition monitoring program undertaken for more than 100 major turbomachinery trains. Details of the RTA minicomputer system are given along with recommendations for practical use in refineries. The minicomputer automatically controls the real-time analyzer for vibration spectrum input. It has the capability to read a spectrum, then automatically erase, reset and restart the RTA in a second operation immediately following receipt of the data. Other peripheral devices include a digital to analog (D/A) converter for operating X-Y plotters or producing a CRT type display on a standard laboratory oscilloscope.

A Feasibility Study for Monitoring Systems of Fatigue Damage to Helicopter Components

Abstract: : The report describes efforts to monitor and record the in-flight operations of UH-1H and CH-47C helicopters for the subsequent assessment of the fatigue damage to their structures, four types of monitoring were investigated: (1) flight condition monitoring, (2) component-load monitoring, (3) mission-type monitoring, and (4) direct monitoring. After the recording systems and corresponding data processing systems were identified for each monitoring type, each type was tested for its technical acceptability and cost-effectiveness. Study results indicated that the flight condition monitoring is best for the UH- 1H and also for the CH-47C provided that the monitoring of gross weight for the latter model becomes technically acceptable.