Method and apparatus for regulating the internal pressure of a ventilated, closed space subjected to variations in external pressure

A method of regulating an internal pressure P.sub.i of a ventilated, closed volume subjected to variations in external pressure P.sub.e, said method comprising the steps of:

• supplying information to a regulating system using an internal pressure sensor when the pressure P.sub.i inside the volume drops below a reference pressure P.sub.ref,
• at least partially closing an air extraction circuit using the regulating system, so as to cause a corresponding extraction air flow rate q.sub.2 to drop, while an intake circuit remains open, so that a difference between an intake air flow rate oil and the extraction air flow rate q.sub.2 algebraically compensates for a leakage flow rate q.sub.f, and maintains the pressure P.sub.i at a constant level which is close to at least one of the reference pressure P.sub.ref and setpoint pressure P.sub.c ;
• partially closing the air intake circuit using the regulating system, while the extraction circuit remains open, when the pressure P.sub.i inside the volume rises above the reference pressure P.sub.ref ;
• and
• keeping the intake circuit and extraction circuit open when an instantaneous internal pressure P.sub.i is equal to the reference pressure P.sub.ref.