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Figure 8-26. Installation details for pressure oriented instrument piping [11.

API 670, "Vibration, Axial Position, and Bearing Temperature Monitor ing System" includes temperature in its scope. For several years, radial and thrust bearings have been instrumented using either thermocouples or RTDs. Each user specifying the instrumentation had the bearings fitted in his own way. While this gave good data in some instances, it was not consistent. Furthermore, the data from one user could not be compared with the data from another. In fact, because of different influences by the various compressor vendors, one large user could not correlate his own experience. While the addition of bearing temperature monitoring to the API standard has numerous benefits, the more immediate one is the establishment of a standard method of installation. Figures 8-27 and 8-28 show the recommended installation position on the radial and thrust bearing respectively.

Figure 8-27. Typical radial bearing temperature sensor installation.
Figure 8-28. Typical thrust bearing temperature sensor installation.

The two recognized standard sensors are the ISA type J thermocouple (iron-constantan) and the 100 ohm at 0°C platinum 3-wire RTD. Additional attributes such as TFE insulation and stainless overbraid are specified. The sensors are installed in a drilled hole at die location shown, with the objective being to place the sensor approximately .030 inches to the rear of the base of the babbitt. Surprisingly, steel conducts at approximately the same coefficient as the babbitt, so there is no significant temperature drop at the metal interface. The sensor is potted in place, with some of the over-braid included, to provide strain relief. An alternate to potting is to use a spring and clip arrangement, which has the advantage of an easy sensor replacement. Figure 8-29 shows a radial bearing with a temperature sensor installed. Figure 8-30 depicts an instrumented thrust bearing.

Flow

Flow is another one of the basic compressor parameters. It can be deferred back to pressure, since mosl of the flow involving compressors is measured flow by a primary device such as an orifice and a differential pressure sensor as discussed in the section on pressure. For plant use.

Figure 8-29. Radial bearing with a temperature sensor installed. {Courtesy ofA-C Compressor Corporation)
Figure 8-30. Thrust bearing pad with a temperature sensor installed. (Courtesy of Turbocare, A Division ofDemag Delaval Turbomachinery Corp., Houston facility)

where relative flow is generally of more interest, the flow is usually recorded on a flow chart. The chart is calibrated in square root units. Unfortunately, unless all the constants can be located, the relative flow is not of much value. If a differential transducer is connected across a primary element with a known bore and pipe size, and if the element was calibrated, the calibration chart will provide the raw data that will permit the generation of meaningful flow information.

Renewable Energy 101

Renewable Energy 101

Renewable energy is energy that is generated from sunlight, rain, tides, geothermal heat and wind. These sources are naturally and constantly replenished, which is why they are deemed as renewable. The usage of renewable energy sources is very important when considering the sustainability of the existing energy usage of the world. While there is currently an abundance of non-renewable energy sources, such as nuclear fuels, these energy sources are depleting. In addition to being a non-renewable supply, the non-renewable energy sources release emissions into the air, which has an adverse effect on the environment.

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