OVERVIEW

An accurate performance evaluation of a dynamic rotary compressor is of paramount interest to the builder because it defines the ability of a machine to perform a specific job and the related requirement for energy expenditure. Since the compression process is continuous rather than batch (as in reciprocating compressors), the physical dimensions of the compressor will not permit accurate performance evaluation. Instead, the characteristics of the machine must be determined by calculation from work done on the gas, as indicated by measurement of observable gas conditions. While a compressor builder might be quite satisfied with relative values for gauging development work, absolute determinations must be made for effective comparison of a machine with its peers. To facilitate such comparisons, a code of practice has been established by the ASME, Power Test Code 10 (PTC 10). It sets guidelines for conducting and reporting tests on a compressor under certain conditions. A compressor's thermodynamic performance on a specified gas of known properties may be determined during the compression process where, under specified conditions, no condensation or evaporation occurs and there is no injection of liquids.

The code defines conditions and provides methods by which a compressor may be tested on a suitable test gas, and the results can be converted into anticipated performance of the same compressor when pumping the specific gas at design conditions. Also, guidelines are provided for testing compressors with interstage sidestream inlets or outlets, internally cooled compressors, and uncooled tandem-driven compressors with externally piped intercoolers.

TEST PLANNING