Dr. David Lyness@Gas_Craic
Different colours, different valves, different uses
O2 - White
CO2 - Grey
The PIN system is designed so that an oxygen YOKE cannot fit on to a CO2 cylinder by accident (and vice versa etc.)
A Shrader Valve allows only the connection of the correct type of demand-tube.
Gas is usually supplied under high pressure either
in cylinders or as a piped gas supply.
E & J cylinders are the most common in hospital
E = 680L of O2 or 1800L of Nitrous Oxide
Stored as liquid with vapour on the top.
Nitrous oxide, which is liquefied by the high pressure within the cylinder.
Here, the pressure remains relatively constant until all of the liquid is evaporated, after which the pressure drops rapidly as the remaining gas is removed (this is unlike O2) The contents of these cylinders can only be estimated by weighing.
Anaesthetic gas pipework terminates in outlets that are in the form of self-closing sockets.
The terminal unit consists of two sections:
1. Termination assembly
This part is permanently attached to the appropriate pipeline
2. Schrader Socket
Designed so that it cannot be accidentally connected to a different gas service.
The Schrader socket will accept a probe with a collar indexing system that is unique to each gas service.
To prevent connection to the wrong gas service, the probe has a protruding indexing collar.
This collar has a unique diameter that fits only the corresponding recess fitted to the socket assembly for that gas.
Flexible PipelinesThese connect the terminal outlet to the anaesthetic machine.
- Schrader probe (fits the terminal outlet)
Others are measured by a pressure gauge more accurately
Nitrous oxide would present as 'full' until it's nearly empty