open during the fill stroke to enable fluid to be drawn from the liquid source through the intake line 16 into the syringe 10 the valve 18 being closed during the pump stroke to prevent fluid from exiting the syringe through the inlet port the valve 19 controls the outlet port 10e and is open during the pump stroke to enable fluid delivery from the syringe 10 to the patient through the output line 17 the valve 19 being closed during the fill stroke the valve control system 20 is also driven through the gearing 14 by the same drive motor 13 as is used to operate the syringe 10 the valve control system 20 also provides information to the electrical control system 15 controlling the motor 13 indicating that the syringe 10 is either in the fill stroke or the pump stroke and this information in turn enables the electrical control system to establish the proper direction of rotation of the motor the electrical control system 15 may be of conventional design for electrically energizing the motor 13 and controlling its direction of rotation or the control system may be of the form described in copending application ser no 554 092 entitled fluid flow control system inventor heinz w georgi filed feb 28 1965 and assigned to the same assignee as the present application a copy of the specification and.