GB1498241A - Well-drilling turbodrill - Google Patents

Abstract

1498241 Boring earth VSES NI INST BUROV TEKH 17 July 1975 30002/75 Heading E1F [Also in Division Fl] The invention relates to a hydraulic welldrilling turbine in which two thrust bearings are provided for supporting the shaft, the shaft being provided with flexible means between the two thrust bearings whereby the upper thrust bearing is relieved of hydraulic load and so the possibility of contact between the rotor and stator parts of the turbine is reduced. In Fig. 1 the assembly comprises a stator casing comprising parts 4, 5, 6, 7, 8, 9, 10 secured together by screw engagement, the part 4 being connected to the lower end of the drill string (not shown), the part 10 carrying a thrust bearing 2, and the part 8 carrying an additional thrust bearing 17. A shaft assembly comprising parts 1, 12, 13, 14 secured together is rotatably mounted within the stator casing being supported on the bearings 2 and 17. The stator casing part 5 carries stator blade rings 16 which co-operate with rotor blade rings 15 carried by the shaft part 11, drilling fluid being supplied to the turbine through the drill string. The part 13 of the shaft assembly is formed as a resilient member in the form of a helical spring 18 whereby thrust of the drill bit is absorbed by the spring and the thrust bearing 2 but is not transmitted to the thrust bearing 17 whereby the life of the turbine is prolonged. In place of a helical spring, a resilient bellows member (19) is utilised in Fig. 2 (not shown), and a stack of Belleville washers in Fig. 4 (not shown). In Fig. 3 the shaft part 12' is connected to the shaft part 14 by means of a coupling device 21, 22 which allows transmission of torque also axial movement of the two parts; a compression spring 20 is disposed between the two shaft parts.