Cavallini:
a family of submarines

by Cristiano D'Adamo

Air Systems

The compressed air system was one of the most important systems on the submarine. It was used to blow the ballast tanks, fire torpedoes, and to start the main engines. Without a functional air system the submarine became inoperable. Docking facilities were usually provided with the necessary high-pressure air supply so that the submarine would not have to produce its own. Air tanks dented to accumulate condensed moisture (water), thus they were regularly drained for maintenance.  On the “Mameli” and “Settembrini” the primary air compressor was installed in the control room. It was build by San Giorgio and capable of pressurizing air up to 210 kg.cm2 (2987 psi) and producing 9 liters per minute (0.31 ft3 per minute). The compressor was powered by a 50 HP electric motor.  There were also two super compressors, also built by San Giorgio, capable of boosting air pressure from 70 to 225 kg.cm2 (995 to 3200 psi), and producing 9 liters per minute. They were driven by a 10 HP electric motor rotating at 670 r.p.m. This system received air from the two compressors built into the diesel engines and air was stored into three tanks with a total capacity of 4,580 liters (162 ft3).  The “Archimede” had the air supply increased to 8,000 liters (282 ft3) and pressure reduced to 200 kg.cm2. The “Brin” probably maintained the same configuration, while the “Liuzzi” were equipped with a total of 5 tanks for a total capacity of 10,000 liters (353 ft3). Air was used to exhaust the ballast tanks only under emergency conditions; usually these tanks were exhausted utilizing two rotor-compressors of the type Reavel-Cerpelli, capable of producing 30 m3 (1059 ft3) of air per minute at a pressure of about 1.6 to 1.8 atmospheres. Each compressor absorbed 60 HP and rotated at about 1,600 RPM. These compressors could only be used when the submarine had at least the cunning tower out of the water so that the hatch could be open to supply external air.  The “Archimede” were fitted with four pumps, two capable of 50 t at 150 meters, and two of 30 t also at 150 meters. There were also two low-pressure blowers (less than 2 atmospheres) capable of 30 m3. The blowers shared the same electric motors as the pumps. The boats were also equipped with emergency pumps driven by low-pressure air or manpower.

Air Filtering System