Anaesthetic gas pipework terminates in outlets that are in the form of self-closing sockets.
The terminal unit consists of two sections:
This part is permanently attached to the appropriate pipeline
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.
These connect the terminal outlet to the anaesthetic machine. There are three components:
Schrader probe (fits the terminal outlet)
NIST connection (fits the anaesthetic machine)
Non-interchangeable Screw-Threaded Connection (NIST)
These ensure that the gas services attach correctly to the anaesthetic machine. Thus each hose is fitted with a unique connector. The probes are gas specific and non-interchangeable. The nut has the same diameter and thread for all the gas services.