Angiographic injector with pump motor starting control

Claim 2

An angiographic injector comprising: a catheter adapted to be inserted into a patient''s vascular system; a pump for propelling radio-opaque material through said catheter; an electric motor for driving said pump; at least one semiconductor current control device; means for connecting said motor means to an electric power source through said current control device so that the energization of said motor means is controllably variable; means for generating a control signal having an amplitude which varies in accordance with a predetermined gradual time function having a preselectable time constant, starting at a controllable point in time, said generating means including means for adjusting said time constant; means for varying the conduction of said current control device as a function of said control signal to progressively energize said motor means and thereby prevent whipping of the catheter tip.

Claim 3

An angiographic injector comprising: a catheter adapted to be inserted into a patient''s vascular system; a pump for propelling radio-opaque material through said catheter; an electric motor for driving said pump; at least one triggerable semiconductor current switching device; means for connecting said motor to an a.c. power source through said current switching device so that the energization of said motor is variable as a function of the phase angle of triggering of said switching device relative to the phasing of the source power; a first capacitor; means for applying a preselectable d.c. charging current to said first capacitor when said motor is energized thereby to generate a control signal voltage which changes gradually over a plurality of cycles of said a.c. source, said charging current applying means including means for manualLy adjusting the value of said charging current; a timing capacitor; means for applying a first charging current component to said timing capacitor; means for applying a second charging current component to said timing capacitor when the timing capacitor voltage is below said control signal voltage; and a voltage breakdown device interconnected with said timing capacitor to generate a pulse for firing said triggerable semiconductor current switching device within each half cycle of the source a.c. when the voltage on said timing capacitor reaches a predetermined value, the phase angle of firing being progressively advanced relative to the phasing of the source power, whereby said motor is progressively energized and whipping of the catheter tip is prevented.

Claim 4

An angiographic injector comprising: a catheter adapted to be inserted into a patient''s vascular system; a pump for propelling radio-opaque material through said catheter; an electric motor for driving said pump; at least one triggerable semiconductor current switching device; means for connecting said motor to an a.c. power source through said current switching device so that the energization of said motor is variable as a function of the phase angle of triggering of said switching device relative to the phasing of the source power; a first capacitor; means for applying a preselectable d.c. charging current to said first capacitor when said motor is energized thereby to generate a control signal voltage which changes gradually over a plurality of cycles of said a.c. source, said charging current applying means including means for manualLy adjusting the value of said charging current; a timing capacitor; means for applying a first charging current component to said timing capacitor; means for applying a second charging current component to said timing capacitor when the timing capacitor voltage is below said control signal voltage; and a voltage breakdown device interconnected with said timing capacitor to generate a pulse for firing said triggerable semiconductor current switching device within each half cycle of the source a.c. when the voltage on said timing capacitor reaches a predetermined value, the phase angle of firing being progressively advanced relative to the phasing of the source power, whereby said motor is progressively energized and whipping of the catheter tip is prevented.