  We introduce here a coherent technique to inject, extract, and velocity
filter neutral atoms in a ring trap coupled via tunneling to two additional
waveguides. By adiabatically following the transverse spatial dark state, the
proposed technique allows for an efficient and robust velocity dependent atomic
population transfer between the ring and the input/output waveguides. We have
derived explicit conditions for the spatial adiabatic passage that depend on
the atomic velocity along the input waveguide as well as on the initial
population distribution among the transverse vibrational states. The validity
of our proposal has been checked by numerical integration of the corresponding
two dimensional Schr\"odinger equation with state-of-the-art parameter values
for $^{87}$Rb atoms and an optical dipole ring trap.
