Dental anaesthetic appts. electronic safety control system - has monitor to disconnect patient connections when safety level is exceeded

摘要

The dental anaesthetic system as in the main patent has a monitoring arrangement (4) powered by d.c. at the output connections (2, 3) to operate at regular time intervals to check the voltages applied to the patient to ensure his comfort. A nominal value is established so that only at a value below this the equipment is operated. The system includes a switch (d) for the output connections (2, 3). There is also a differentiating circuit (5) with a set of resistance (R1 to R6) connected to a logic switch (6) and to timing units and a unilateral impedance, the latter operating to neutralise a residual voltage and a capacitative potential in the apparatus and controlling the second timing unit to operate a switch (d3) to close a short circuit loop across the apparatus (1) as well as operate the output switch (1). There is also another switch (d) to the input terminals (2, 3).