Field Testing & Diagnostics

A significant amount of EDI’s field testing is performed on reciprocating compressors and pumps, and rotating equipment such as centrifugal compressors and centrifugal pumps.  Solutions of problems ranging from piping vibration to impellar failures are some of the types of problems EDI specializes in.

Torsional vibration is oscillatory angular motion that causes twisting in shaft sections and couplings of machinery. These fluctuations are superimposed on the steady running speed.  High torsional vibration can be destructive and will not usually be detected by accelerometers and proximity probes commonly used to measure lateral vibration.

Piping vibration is caused by forces imposed on it by operation of equipment, most often induced by pressure pulsation.  Generally, the severity of vibration of piping and structures is evaluated using accelerometers, and where fatigue may be an issue, strain gages may be used.

Pulsation is the change in pressure with time.  Pulsation causes piping vibrations and structural vibration, which can result in support degradation and fatigue failures.  Dynamic pressure transducers are used to evaluate pulsation characteristics.

Compressor frames, skids, and foundations are subjected to dynamic forces induced by the compressor inertial shaking forces and pulsation induced forces which can cause excessive vibration.

VFD performance measurements are a critical part of commissioning today’s modern large scale variable speed motors and validation as to long term use acceptability.

EDI maintains a full range of instrumentation for use in diagnostic studies.

Vortex shedding is due to flow over an obstruction in the flow path.  At certain flow velocities, the fluid boundary layer at the trailing edge will separate, or cause vortices that are shed from either side of the obstruction.

Continuous monitoring is becoming more prevalent as operating companies strive to improve availability and reliability of key machinery assets. Another important factor driving the use of these systems is optimization of manpower needed to monitor these critical assets by using on-line systems.

EDI maintains a range of sizes of custom built rotating shakers, including a large shaker capable of producing thousands of pounds of dynamic force.

Most structural failures are due to fatigue (cyclic stress) rather than static loading. A combination of several analysis methods aid in defining the “root cause” of a structural failure. A combination of several analysis methods will aid in defining the “root cause” of a structural failure.

ODS testing is an extremely useful tool for determining the vibration “shape” of machines and structures. Vibration data is obtained at various points on the structures and the data are animated using the amplitude and phase relationships and the corresponding test points of a 3-D model.

EDI uses the IRIS M^TM technology to produce visualizations of machinery, piping, and foundation vibration.    The videos are often sufficient to identify problems and recommend solutions.  In more complex situations, the information from MAV can be combined with ODS or other diagnostics to develop a complete understanding of a vibration problem.

DI has established a test group to provide routine engine/compressor maintenance and performance analysis services. A predictive maintenance program can significantly improve reliability and reduce maintenance costs of reciprocating machinery.

EDI Performs environmental noise surveys for new or existing plant sites using ANSI S1.4-1983 Type 1 or IEC61672 Class 1 instrumentation. Noise contour maps can be produced to comply with OSHA permissible exposure limits.

A strain gage telemetry system can be used to evaluate actual transmitted and dynamic torque in a shaft.

A torsiograph is an instrument that roataes with the shaft and is used to measure angular velocity (deg/sec) or displacement (degrees).