Shock Response for Equipment Response to Impulsive Loads
Shock Response for Equipment Response to Impulsive Loads Shock response is important for understanding equipment’s response to impulsive loads. An impulsive load can be anything from a mechanical impulse to a water hammer, travelling across road bumps or drops, shock pulses, and explosions. Equipment response includes a variety of systems, e.g. electric cabinets, satellites, motors, generators, coolers, piping, cardboard boxes containing goods, and sensor response. Shock response results can be confusing, as they show response versus resonance frequency. We need to elaborate a bit on the...
read moreSlugging Pulsating Pressure Source Characteristic & Measurement
Multiphase Slugging Pulsating Pressure Source Characteristic & Measurement Slugging in multiphase flows can be caused by a variety of factors (see here and here ), including from pigging operations, operational conditions, where low flow velocity cause mixtures to separate (terrain-induced slugging), or low points where liquids at sufficiently high flow flood the low point cross section and cause periodic slugging (also known as riser slugging), as seen in Figure 1. Periodic slugging can be detrimental to piping fatigue, as it causes large pressure pulsations in the system....
read moreFailure Investigation: The CSI of Machines
Failure Investigation: The CSI of Machines We have all seen TV shows with crime scene investigations, where intelligent persons catch the “insignificant” details that solve the mystery. In a failure investigation, the method is pretty much the same. No detail is too small to be considered. A failure is a trauma for an organisation, even if there are no personal injuries. The stress of failure on the organisation is high and it affects every single employee. Of course, the best way to handle a failure is to not have one, but this is, of course, an impossibility. When the inevitable failure...
read moreBoiler pressure pulsation measurement
A boiler (pressure) pulsation measurement can be made directly by using piezoelectric pressure transducers that are installed into the boiler wall, as seen in Figure 1. Boiler pulsation can also be picked up indirectly using accelerometers placed on the boiler wall, though this setup is limited when compared with the use of pressure transducers, as seen in Figure 2. Comparing the boiler pulsation measurements to known boiler data such as power, gas flow velocity, and so on allows for the assessment of root cause problems such a Vortex Induced Vibration (VIV) on heat exchanger pipes, acoustic...
read moreDesigned Damping
Damping design Many people confuse damping with amplitude reduction. To clarify and define, damping is a process in which vibration energy is converted into heat. This conversion process is nearly perfectly irreversible. In other words, we rid ourselves of vibration energy that is converted into heat. The vibration made when a pipe steel structure is impacted by a hammer blow, as sensed by a triaxial accelerometer, can be heard here: The vibration of the same steel structure with damping added can be heard here: The difference in damping between the two cases is...
read moreComputed Order Tracking with Damaged Tacho Pulse
Rotating machinery can be analysed with rotation angle as the reference. This kind of reference is referred to as a tacho or key phasor, reference. A tacho signal can be analog or digital. The end result is usually Single Pulse, a Square Wave or a train of Square Waves. Most signal analysis systems rely on the tacho pulse being in pristine condition. However, the tacho pulse may become damaged when there is sufficient vibration to shake the tacho sensor and/or the rotating system vibration is sufficient for the tacho probe to malfunction. The tacho pulse may then be damaged, and the square...
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