ultrasound testing

by Thomas J. Murphy, Eng.

The use of ultrasound as a predictive tool has been with us for over 35 years.  Yet, despite its vintage, the use – and, indeed the understanding – of this technology is still not widespread.  This article continues an exploration of airborne ultrasound applications that we started in the June/July issue.  In this article, I will explain how, just by changing from an airborne sensor to a contact probe, we can use ultrasonic inspection in a myriad of mechanical applications.

by Thomas J Murphy, Eng

Measuring the condition of bearings rotating at speeds below 60rpm using vibration is fraught with difficulty. This article describes using a portable ultrasound system as an "intelligent sensor" in association with a normal vibration data collector to overcome this problem. It includes results of measurements taken on a group of rotary crushing machines where this combined approach reduced the measurement time from 21 minutes per measurement to less than a minute per reading.

by Steve Johnson
Computational Systems, Inc

Today's cost-sensitive maintenance environment dictates an effective, simple-to-use, high payback technology where materials cost and personnel training are concerned. Ultrasonic monitoring is such a technology. Most plant systems and equipment generate operational noise of some sort and during failure modes the noise characteristics can change dramatically. Detecting this change and fixing the problem before failure can result in higher quality production output, reduced downtime, reduced maintenance overtime, and greatly reduced costs.

by Stuart Courtney, Senior Applications Engineer, SKF Reliability Systems

Introduction

The purpose of this paper is to introduce condition monitoring and reliability engineers to the principles of using ultrasound for the assessment of machine condition. Ultrasound can be a complimentary technology to vibration, thermography and lubrication monitoring. It must be emphasized that it is rarely successful as a stand alone technology for effective machine condition assessment and subsequent required maintenance planning. This paper concentrates on the use of airborne ultrasound as a complementary technique particularly for machinery that may be inaccessible due to guards or hazardous locations.