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Theory of Operation - CCU Series Manifolds

Theory of Operation

Tri-Tech Medical CCU Series gas manifold system consists of a control unit, and two medical gas cylinder sources.  The two gas sources alternate between “primary” and “secondary” to provide an uninterrupted supply of gas.  The system is designed to provide a reliable uninterrupted supply of gas to a facilities medical gas pipeline system with only small fluctuations in the gas pressure (achieved by parallel line regulators) being provided to the facility and to initiate the three NFPA 99 required master alarm signals; secondary in use, high line pressure and low line pressure. The system shall control two banks of medical gas cylinders such that one bank will be “In Use or primary” while the second bank is held in reserve as the “Ready or secondary” bank either by pressure differential or by a solenoid valve.  The bank that is pressurized first will be recognized by the circuit board logic as the “In Use or primary” bank when the pressure reported by that bank pressure transducer surpasses the minimum required pressure established in the logic.  (It does not matter which bank is pressurized first, but for this example we will assume the left bank has been pressurized first).  Simultaneously, a green “In Use” LED will be illuminated on the circuit board for that bank. The bank that is pressurized second will be recognized by the circuit board logic as the “Ready or secondary” bank when the pressure reported by that bank pressure transducer surpasses the minimum required pressure established in the logic.  Simultaneously, a yellow “Ready” LED will be illuminated on the circuit board for that bank.  Bank pressures will be monitored by the two high pressure transducers and the bank pressures are displayed (in either PSI, or Kpa or Bar) on the circuit board display. As the gas is used,  the “In Use or primary” bank depletes to a predetermined pressure in the logic at which time the secondary in use alarm dry contact will be opened – breaking the normally closed circuit to the master alarm.  Simultaneously, the green “In Use” LED will be extinguished and the red “Empty” LED will be illuminated for the left bank.  At this point the left bank will continue to deplete to a predetermined pressure (the set point of the right bank primary regulator) at which the “secondary” right bank will become the “In Use or primary” bank and begin providing gas to the facility. When the gas source is replenished on the “Empty” left bank, the circuit board will upgrade the status of this bank from “Empty” to “Ready”.  Simultaneously, a yellow “Ready” LED will be illuminated on the circuit board for the left bank.  Simultaneously, the right bank is placed “In Use or primary”, the left solenoid valve will be energized (closed).  It is important to note that the only time the solenoid valve is closed or energized in a CCU (or NPCU or TMCU) series cylinder x cylinder manifold is when the left bank is in a “Ready” or yellow condition.  When the “In Use or primary” right bank depletes to a predetermined pressure in the logic the secondary in use alarm dry contact will be opened – breaking the normally closed circuit to the master alarm.  Simultaneously, the green “In Use” LED will be extinguished and the red “Empty” LED will be illuminated for the primary bank.  Simultaneously the logic board will de-energize the solenoid valve causing it to open and the left bank will begin providing gas to the facility.

 

The low pressure transducer will continuously monitor the line or delivery pressure exiting the system.  Line pressure will be displayed (*in either PSI or Kpa or Bar).  If the delivery pressure drops below and/or rises above predetermined pressures in the logic, the respective line pressure low or line pressure high relay dry contact will be opened – breaking the normally closed circuit to the master alarm. It is important to note that in the event of electrical power loss, the solenoid valve automatically opens.  As the left primary regulator is set at a higher delivery pressure than the right primary regulator, the left bank will provide gas until it is depleted to a pressure equal to the right primary regulator, then the right bank will provide gas until it is completely exhausted along with the residual of the left bank also completely exhausting when the right bank pressure matches the residual of the left bank.


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