with an integral 10-gallon surge tank and pressure regulating equipment built 

 into the flow control console. The compressor plugs into a 110-VAC outlet in 

 the biology laboratory. 



This compressor must be able to supply enough air to the minitat to replenish 

 the metabolic oxygen consumed. Oxygen consumption was projected at an average 

 rate of 1.3 (surface) liters per minute; therefore, the surge compressor should 

 supply an average of 14.6 liters per minute of air (0.52 cfm) to support the 

 two divers in the minitat. The surge compressor supplies over four times the 

 necessary flow rate. 



The low pressure purge air subsystem provides a medium flow rate of low pres- 

 sure air to purge the minitat if the breathing gas becomes contaminated. The 

 low pressure purge air subsystem can change the gas in the minitat in 3.3 

 hours. (Using high pressure air from the on-board compressed air supply it 

 is possible to purge the gas in the minitat in a few minutes) . The low pres- 

 sure purge air subsystem also acts as a backup for the surge air system. It 

 consists of the low pressure 165 psi, 20 scfm side of a HYDAP motor-driven 

 compressor and the necessary plumbing to deliver low pressure purge air to the 

 flow control console. The air hose connecting the compressor to the flow con- 

 trol console is also routed through the protective conduit on the deck. 



The nitrogen make-up gas subsystem provides high pressure nitrogen to make up 

 the minitat breathing gas after emplacing or purging the minitat. The nitrogen 

 is used to dilute the air in the minitat to achieve the desired concentration 

 of oxygen. It consists of a bank of sixteen, 240 SCF cylinders with appro- 

 priate plumbing to deliver high pressure nitrogen to the flow control console. 



The flow control console controls the flow of gas from the other four breath- 

 ing gas supply subsystems to provide the desired pressure, flow rate, and com- 

 position of breathing gas to the minitat. It consists of valves, pressure 

 gauges, and flow rate meters on a panel in the Minitat Control Center (MCC) . 

 Figure 10 shows the arrangement of the flow control console. 



The electrical distribution system supplies power from the ships main power dis- 

 tribution panel in the engine room to the minitat, the HYDAP compressor, and 

 the PTC winch motor. Three phase, three wire, 60 cycle power is generated at 

 230 volts giving about 220 volts at the minitat. Circuit breakers provide 

 100 amps for the minitat and 100 amps for the HYDAP compressor. The minitat 

 draws a maximum of 75 amps and the compressor an average of 27 amps. The PTC 

 winch motor draws about 6 amps. The UNDAUNTED has two 150 KW three phase 

 generators. The ship normally requires 80 KW of electrical power, therefore, 

 with one generator operating, 70 KW is available to support the minitat. 



The communications system on the UNDAUNTED consists of the minitat communi- 

 cations gear in the Minitat Control Center (MCC) , the psychological observers 

 station and the ships communications equipment. In the MCC are the control 

 intercom station, a sound powered telephone, an amplifier and speaker for the 

 open microphone, a television monitor, and a dual channel strip chart recorder 

 for the O2 and COo sensors. Figure 11 shows the minitat communications equip- 

 ment in the M]C. A television monitor and an open microphone speaker are mount- 

 ed in the chemestry laboratory for the psychological observer. The ships 

 communication equipment consists of an RCA transmitter covering 4 to 32 MHz, 

 a Collins receiver, an RCA receiver, an APELCO radio-telephone, and an RCA 

 500 KHz auto-alarm transmitter. 



III-IO 



