A conduit system cleaning apparatus for providing controlled pressure-flow pulses which purge a catheter system with turbulent flow flushing. Accomplishment of such controlled pressure- flow pulses is provided by a variety of inventive devices including a special plunger rod (30) for a conventional syringe (20), other interactive parts for conventional syringes, an in-line catheter attachable device which automatically generates the controlled pressure-flow pulses and also single pulse, finger operated devices.