Process for setting, controlling and monitoring the level in a refrigerant evaporator

A process for setting, controlling and monitoring a filling level of a refrigerant evaporator in a closed circuit of a refrigerating machine and evaporating a mass flow of refrigerant into a substantially dry gas in a suction line of said circuit downstream of said refrigerant evaporator, said process comprising the steps of:

• (a) inserting into said suction line a heatable measuring body so that said body contacts said gas and is impacted by refrigerant drops;
• (b) heating said body to a temperature differential above the temperature of the suction line gas and applying a measuring and evaluation circuit to record a measuring signal representing the energy supplied and establishing a basic signal comprised of a signal component representing electronic noise of said measuring and evaluating circuit and another signal representing passage of dry gas past said body;
• (c) measuring, with said measuring and evaluation circuit during said mass flow, energy needed to evaporate refrigerant drops hitting said body, thereby producing a measuring signal;
• (d) forming a difference between said measuring signal and said basic signal
• (e) comparing said difference with an adjustable reference value establishing a threshold above which the gas traversing said suction line is considered to contain excess liquid;
• and
• (f) setting, controlling and monitoring said filling level in response to determination as to the liquid content of said gas in said suction line.