An Apparatus for Controlling Supply of Protective Gas to an Electrode of a High-Frequency Surgical Coagulating Instrument

Abstract

Abstract 1,165,148. Cutting electrodes. O. H. DRAGER [trading as DRAGERWERK, HEINR. & BERNH. DRAGER]. 23 Dec., 1966 [23 Dec., 1965]. No. 57803]66. Heading A5R. A control arrangement for the supply of gas to a high frequency cutting electrode 11 includes an electrical or pneumatic switch 6, 12 responsive to pressure in a gas supply duct to prevent energisation of the high frequency circuit unless the gas reaching the electrode is above a predetermined pressure. Gas, eJg. nitrogen, is .supplied to the electrode via a pressure .regulator 2, a large volume vessel 3, an electromagnetic valve 4, a connecting duct 14 .switches 6, 12 and 7, 13 and a duct 9 and a throttle 10 provided in the electrode, a detachable connection 8 connecting the ducts 14 and 9. Pneumatic devices 6, 7 hold the switch contacts 12, 13 closed unless the pressure in the connecting duct 14 is below' a predetermined minium or above a predetermined maximum, respectively. Actuation of a foot or manual switch 5, (15) opens the electromagnetic valve 4, for supplying gas to the electrode and connects the high frequency generator HF to the electric supply. The switch contacts 12 remain open until the pressure in the connecting duct 14 has reached the desired operating pressure, when it closes to energise the high frequency generator. If the gas supply fails or the electrode is disconnected at the connection 8, the switch contacts 12 are opened to disconnect the generator. If the throttle 10 or the gas outlet of the electrode becomes blocked, the switch contacts 13 are opened to disconnect the generator. The large volume vessel 3 supplies gas to quickly build up the required pressure in the duct 14 in the event that use of the electrode is interrupted for a short time and thus reduces the delay between the operation of the gas supply and the generator when the switch 5 is closed again. In an alternative arrangement (Figure 2), the switch contacts 12, 13 are arranged in a circuit including a time delay switch (BS) and relays which control the energisation of the generator circuit.

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