Patent GB-462987-A (GB)
Title: Method of and means for making bore-holes by electric melting
IPC: E21B7/15
Filed: 1935-09-25
Abstract: 462,987. Boring earth by heat. NAAMLOOZE VENNOOTSCHAP SMELTBORING. Sept. 25, 1935, No. 26568. Convention date, Aug. 2. [Class 68 (i)] [Also in Group XI] Boreholes are made by electric melting by placing a boring pot in the ground, passing current between the pot and the electrodes of a burner positioned in the pot in order to form a gas tight connection between the pot and the beginning of a glass-like lining formed from fusible material in the bore-hole, and then passing current between the electrodes of the burner to form the borehole. The burner has a depending portion with an orifice at its lower end through which the slag is forced into the burner by the pressure of gas supplied to the borehole and a pump is provided to circulate liquid through the burner, the slag passing out of the burner with the liquid. Means for separating the slag from the liquid are provided between the burner and the pump. The supply leads for the electrodes and the pipe through which the liquid circulates are passed through the cover of the boring pot in a gastight manner. The borehole may be started by supplying a mixture of fusible material, e.g. graphite and glass powder, preferably in the form of compressed balls. In the form shown in Fig. 1 the boring pot 1 has a cover 2 through which is passed in a gastight manner a pipe 26 which supports at its lower end a burner 29 having three electrodes 4 mounted in holders and a depending portion 36 with an orifice at its lower .end. The pipe 26 also carries, by means of an insulated plate 28, three pipes 11, 12, and 15 which carry the electric current, the pipes being interrupted at 27 by insulation from above which leads are carried down to the electrodes. Liquid is circulated through the burner 29 by a pump 9 which is connected through a valve 10, by means of which the pressure in the circuit may be varied, with the pipe 11, the liquid being withdrawn from the burner through the pipe 12. The slag melted by the current passing between the electrodes is forced into the burner by the pressure of gas, which as shown is exhaust gas from the motor 7, but may be ammonia, marsh gas, or compressed air, supplied to the borehole from the compressor 24, and is carried up the pipe 12 with the liquid and is separated therefrom in the vessel 18, any gas which separates from the liquid being returned from the vessel 18 to the compressor 24. To prevent clogging of the orifice through which the slag passes into the burner a pin is provided which is preferably hydraulically operated by liquid in the pipe 15 which is connected to the main supply through a three-way valve 17. The pipe 26 carrying the burner &c. can be raised or lowered by caterpillars 30 worked by a drum 31 in which the satellite wheels 32 of a differential box are rotatably mounted. By driving the bevel wheels 33 of the box by two electromotors or by one electromotor with a rotating stator the boring speed can be controlled and may be made dependent upon the electric resistance in the bore hole. A simple burner for use with one phase current is shown in Fig. 2, two concentric tubes 11, 12 being employed and means 34 being provided to give a rotating movement to the liquid as it enters the tube 12 to increase the ejector action. Fig. 3 shows a form of burner having three electrodes 4 in which the slag is first forced into and up a depending pipe by the gas and then carried into the pipe 12 by the circulating liquid. The liquid, in addition to raising the slag, also cools the electrode holders which are hollow and communicate with the burner.