Ratio of super feed flow to total flow in refrigeration cycle

[Little Prince]

Hi everybody;
I am curious about the recommended ratio of super feed flow to total flow in the two stage refrigeration with economizer cycle?
Is there any ratio at all? does it depend on each compressor manufacturer or it depends on type of super feed in use (i.e. Open flash, shell and coil and etc.)?
I have heard somewhere it cannot be mote than 1/3 but I am not sure if it is true.


Thanks in advance.

[sterl]

It depends on each compressor and the relative volume of the full pressure ratio, suction gas to the side port, suction gas. For a screw compressor: the port needs to be considerably smaller than the lobe to lobe dimension in one direction and somewhat smaller than the lobe depth in the other....so the lobe pitch, lobe diameter, screw pitch and lobe ratio are all mixed into the available volume equation.