The two main types of compressors are dynamic and positive displacement. The positive displacement compressor is probably the one you’re most familiar with. It traps gas in a volume and then decreases that volume. The decrease in volume causes a rise in pressure. A dynamic compressor uses a rotating element (usually called an impeller) which…
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The goal of a precision alignment is to align the machine within tolerance when at operating condition. Many, but not all, machines are aligned without the need to compensate for offline to running (OL2R) movement most often associated with thermal growth. A previous blog post (see link below) discussed how to read an alignment report…
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Even though laser shaft alignment systems have been in use for over 3 decades some industries have alignment tolerances and cold alignment targets in dial indicator terms or language. Take for instance the gas compression and processing industry. Many OEM’s, packagers, end users, and service companies use laser alignment systems, however their cold alignment targets…
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A client was aligning a motor-compressor set and wanted to use the OEM specifications for thermal growth (OL2R) compensation. The manual gave the target values as rim and face dial indicator numbers for either the motor hub or compressor hub. In this case the motor hub specifications were used. He was using the Fixturlaser NXA…
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In shaft alignment, machines that run hot often have thermal growth targets. Thermal targeting simply means that the shafts may be misaligned while at room temperature, but as they heat up to operating temperature, they will “grow” into alignment. But where does the thermal growth target come from? Many times, the machine manufacturer will specify…
Read MoreThe object of precision shaft alignment is to position machines so that the rotational centers meet a specified tolerance at operating conditions. Machines can and will move due to temperature changes or process forces so this means that some machines need to be “misaligned” in their off line or cold condition so that they will…
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