Dual Tube Flowmeter With AHD

Function 

The Flow Head incorporates the following Functions

• Gas indexed pneumatic inlet ports
• N20 gas flow cut off in the event of oxygen failure
• Flow control needle valves
• N20/O2 flow ratio hypoxic mixture prevention proportioning system
• Color coded, marked specific labels for flow tubes and flow control valves
• Gas mixing chamber, mixed gas outlet

GENERAL OPERATION

The Flow Head integrates O2 and N20.

The 02 Air and N20 needle valves gas supply pressure is externally regulated to 400Kpai10Kpa as per standard.

The N20 channel incorporates a pressure cut-oft valve. The 02 supply pressure in the circuit controls the output pressure of the pressure cut-off valve. Under all conditions of operation, the N20 flow shall reach zero before the 02 flow. In this flow head the N20 pressure switch shall cut off the flow of N20 before the 02 pressure drops below 50:15Kpa.

PERFORMANCE STANDARDS

Standard flow conditions defined at 20°C, 101 .3Kpa, (760mmHg) Conforms to ISO 5358 requirements.

Flow Tubes

•  Flow Tubes are calibrated for discharge into an ambient atmosphere of 101 .3Kpa at an operating temperature of 20°C.
• Each flow tube shall be calibrated to accuracy of 110% of reading, or better.
• Flow tubes withstand 690Kpa internal pressure without breaking.

Flow Control Valves

• Anti-clockwise rotation shall cause an increase inflow.
• Flow control knob are color coded and touch coded. Smooth and precise rotation ensures accurate flow setting

PRESSURE CUT-OFF VALVE

• N20 regulated pressure shall drop with falling of 02 supply pressure and shall prograssively reduce flow of this gas while
• maintaining the proportion of 02 (22% min.) until O2 pressure falls to 50i15Kpa at which point the supply of N20 shall be cut off.
• The only means of restoring N20 flow after 02 supply failure (O2 pressure below 50i15Kpa) shall be the restoration of 02 pressure.

ASSEMBLY

Leakage from atmosphere shall not exceed 108ml/min. when a vacuum of 80cm H20 is applied to all internal.

MATERIALS

• All wetted material are compatible with all gases used and all anaesthetic agents.
• Equipment compiles with HoHS requirements.