CAIRE COMPANION 1000 Technical Manual

Contents

CAIRE COMPANION 1000 Technical Manual Manual pdf 36 page image

Companion 1000/T Liquid Oxygen System Technical Manual2-8 Theory of Operation B-701964-00 Rev. C2.3.3 StandbyWith the vent valve and flow control valve closed and liquid oxygen in the Companion1000/T Portable (Figure 2-12), the pressure in the inner container soon stabilizes at theprimary relief valve set point, approximately 22 psig (152 kPa). The liquid oxygenmaintains saturation at this pressure due to the normal evaporation rate (NER) of thesystem.The NER is a function of the rate at which ambient heat "leaks" into and warms theliquid oxygen in the inner container. Once the liquid oxygen is at saturationtemperature, continued heat infiltration readily vaporizes some of the liquid oxygen intogas. This gas builds pressure in the headspace above the liquid until the relief valveopens. Once open, the relief valve vents excess vaporized gas to maintain the systempressure at a constant 22 psig (152 kPa). The vented gas represents the system's NERloss.Figure 2-12: Standby2.3.4 Oxygen FlowThe primary relief valve on the Companion 1000/T establishes both the maximumsystem pressure and the operating pressure. Internal system pressure increases until thecracking pressure of the primary relief valve is reached at 22 psig (152 kPa). Theprimary relief valve vents gas to maintain the system pressure at the primary relief valveset point (Figure 2-13). The rate at which gas vents through the primary relief valve isdetermined by the NER of the system.With the flow control valve set to the desired flow, pressure drops to atmosphere acrossthe flow control valve. System pressure forces liquid up the liquid withdrawal tube intothe warming coils, where it vaporizes and warms to near ambient temperatures.Gaseous oxygen enters the flow control valve at approximately 22 psig (152 kPa).If the Companion 1000/T is accidentally tipped over, the primary relief valve circuitdelays liquid oxygen leakage from the primary relief valve for approximately 60seconds. The relief valve tube length, along with the relief valve silencer, enables liquidentering the tube to vaporize into gas before reaching the relief valve.VacuumGas MoleculesLiquid OxygenGaseous Oxygen Molecular SieveFemaleQuick ConnectLiquidWithdrawalTubeFillTubePressure22 PSI(152 kPa)PrimaryReliefValve22 PSI(152 kPa)SecondaryRelief Valve30 PSI(207 kPa)ManifoldVent TubeWarmingCoilsFlowControlValveCompanion T Companion 1000