GB877630A - Improvements in or relating to deep borers - Google Patents

Abstract

877,630. Boring earth &c. GRUBER, J. Nov. 19, 1959, No. 39208/59. Class 85. An electrically driven boring-means comprises a housing having an oil-filled space protecting a bearing from the scavenging fluid, the space being in communication with one side of a piston in a cylinder, the other side being subjected to the pressure of the scavenging fluid so that variations in the said pressure produces corresponding variations in the pressure of the oil protecting the bearing. The upper part of the apparatus, shown in Fig. 1, joins on the lower part shown in Fig. 2, the whole comprising a tube 1 screwed into a member 2 to which the motor casing 5 is screwed, a stator 12, an armature 22, cable 13, a rotary tube shaft 23, thrust bearings 26, and a boring- head 24, 25, having a space 35 for receiving the scavenging fluid and discharge nozzles 36. The member 2 has two cylinders 28, 31 for pistons 3,4, the spaces above the pistons being connected by pipes 29, 32 with a space 30 in communication with the space between lipped washers 9, 10, and with a space 33 in communication through the motor with spaces above pistons 15, so that variations in the pressure of scavenging fluid in the space below the pistons 3, 4 are correspondingly transferred to the oil in the spaces 28, 31, 30, 33, and, by a pressure transference by the pistons 15, to the oil in the thrust-bearing space, this latter pressure acting on the lipped washer 18 to prevent entry of well fluid at this point, When the boring tool is operating, the thrust bearings are relieved of duty, the boring pressure being applied by the pressure of the pumped scavenging fluid built up in the space 35 by the constructions of the nozzles 36. The space 8 is packed with grease. A member 6 may be easily removed, for replacement of washers 9, 10 and a pressuretransmitting packing 7, by unscrewing the head 2.