TABLE OF CONTENTS The following data are for use in the approximation of horsepower needed for compression of gas.
The "N value" of gas is the ratio of the specific heat at constant pressure (C p) to the specific heat at constant volume C v.
If the composition of gas is known, the value of N for a gas mixture may be determined from the molal heat capacities of the components. If only the specific gravity of gas is known, an approximate N value may be obtained by using the chart in Figure 1.
Piston Displacement of a compressor cylinder is the volume swept by the piston with the proper deduction for the piston rod. The displacement is usually expressed in cubic ft per minute.
Clearance is the volume remaining in one end of a cylinder with the piston positioned at the end of the delivery stroke for this end. The clearance volume is expressed as a percentage of the volume swept by the piston in making its full delivery stroke for the end of the cylinder being considered.
Ratio of compression is the ratio of the absolute discharge pressure to the absolute inlet pressure.
Actual capacity is the quantity of gas compressed and delivered, expressed in cubic ft per minute, at the intake pressure and temperature.
Volumetric efficiency is the ratio of actual capacity, in cubic ft per minute, to the piston displacement, in cubic ft per minute, expressed in percent.
Adiabatic...
