[New diagrams for quick calculation of refrigerating machines (author's transl)]

The present edition is a re-elaboration and an extension of a previous one and takes into account the data meanwhile brought up to date--concerning the characteristics of saturated vapours--as well as the opportuneness of an easier consultation. In fact, by introducing logarithmic scales and by an appropriate choice of the logarithmic modulus, it has been possible to summarize the characteristics of each fluid in one diagram only, whereas, in the first edition, the extension of the metric scales of the abcissas imposed to divide each diagram in two parts. Besides, more units have been introduced, namely: m3/kcal, m3/kj and ft3/Btu for volumes; oF and oC degrees for temperatures. These new diagrams have heen developed for the following refrigerant fluids: R 11, R 12, R 13, R 13 B1, R 22, R 114, R 502, NH3 and CH3Cl. Known the temperature before the throttling device, the evaporating temperature and the one of the eventual superheating, they enable to promptly calculate the volume of the refrigerant in the gaseous phase, both as dry saturated vapour and superheated vapour; besides, they allow the quick calculation of the speed of the fluid inside thepiping system, the performance of the compressor under different working conditions and with different refrigerants, and so on. A number of practical examples illustrate even more clearly what stated about quickness and possibilities of calculation.