| abstract |
A magnetic transponder (30) is mounted around the valve fitting (16) on the ferrous body (12) of a compressed gas bottle (10) to enable remote identification of the bottle. A metal valve guard (40) encircles the valve filling (16), for the protection of the filling during transportation, which shields the bottle transponder from an external reader/exciter. In order to couple RF signals between the reader/exciter, which is outside of the valve guard and the transponder, which is inside of the valve guard, a coupler is provided having a first receive and transmit antenna outside of the valve guard and a second transmit receive and transmit antenna inside of a valve guard adjacent the transponder antenna. Electrical current carrying wires interconnect the two coupler antennae and extend through a wire receiving aperture formed in the valve guard. Alternative forms of coupler are shown in figures 4, 5. <IMAGE> |