摘要:
Method for controlling the pressure and temperature of a fluid, in particular helium, in a series of cryogenic compressors, comprising the steps of: detecting an actual rotational speed for each compressor(V 1 , V 2 , V 3 , V 4 ), detecting an actual inlet pressure(p ist ), and also an actual inlet temperature (T ist ) at the entry of the furthest-upstream first compressor (V 1 ) of the series, providing a maximum speed (n i , max ) for each compressor (V 1 , V 2 , V 3 , V 4 ) of the series, and also a setpoint inlet pressure (p soll ) for the first compressor (V 1 ) of the series, determining a speed index (D i ) for each compressor (V 1 , V 2 , V 3 , V 4 ) from the maximum speed (n i , max ) and the actual speed (n i ) of each compressor (V 1 , V 2 , V 3 , V 4 ), determining a proportional value (prop) from the deviation of the actual inlet pressure from the setpoint inlet pressure (p ist , p soll ), determining a priority value (PW) from the smaller of the two values; proportional value (prop) and the smallest speed index (D i ) of all the compressors (V 1 , V 2 , V 3 , V 4 ) of the series, ascertaining a setpoint entry temperature (T soll ) for the first compressor (V 1 ) of the series and a setpoint speed (n 1 soll , n 2 soll , n 3 soll , n 4 soll ) for each compressor (V 1 , V 2 , V 3 , V 4 ) from the priority value, determining the actual inlet temperature (T ist ) of the first compressor (V 1 ), to the ascertained setpoint inlet temperature (T soll ), determining the actual speed (n i ) for each compressor (V 1 , V 2 , V 3 , V 4 ) to the ascertained setpoint speed (n 1 soll , n 2 soll , n 3 soll , n 4 soll ).