Pressure regulator

A method for regulating pressure of a fluid, the method comprising:

• providing a pressure regulator comprising:
• an inlet passage connectable to an inlet conduit of a fluid at an inlet pressure;
• an outlet passage;
• a supply valve placed in a valve seat between the inlet passage and the outlet passage and provided with adjustment means to regulate an outlet pressure of the fluid in the outlet passage so that the outlet pressure is proportional to the inlet pressure;
• an outlet pressure sensor to detect the outlet pressure;
• a loading electromechanical valve comprising an inlet in fluid communication with the inlet passage and an outlet in fluid communication with the supply valve;
• an unloading electromagnetic valve comprising an inlet in fluid communication with the supply valve and an outlet;
• a regulator control circuit operative connected to the loading electromagnetic valve and to the unloading electromagnetic valve and configured to pilot the loading electromagnetic valve and the unloading electromagnetic valve to cancel an error signal given by a difference between an inlet signal corresponding to a desired outlet pressure and a feedback signal provided by the outlet pressure sensor;
• the pressure regulator further comprising an engaging current analysis circuit configured to:
• detect and store reference characteristics of a waveform of an engaging current of a solenoid of the loading electromagnetic valve in a stable inlet pressure condition;
• monitor, during operation of the pressure regulator, the waveform of said engaging current to detect any variation of its reference characteristics with respect to the corresponding reference characteristics;
• and
• in the event of variation, provide a pilot modulation signal to at least one of the loading electromagnetic valve or the unloading electromagnetic valve and/or a pressure variation signal to the regulator control circuit;
• detecting and storing the reference characteristics of the waveform of the engaging current of the solenoid of the loading electromagnetic valve in the stable inlet pressure condition;
• monitoring during operation of the pressure regulator, the waveform of the engaging current to detect any variations of its characteristics with respect to the corresponding reference characteristics;
• and
• in the event of variation, providing the pilot modulation signal to at least one of the loading electromagnetic valve or unloading electromagnetic valve and/or the pressure variation signal to the regulator control circuit.