Patent GB-360523-A (GB)
Title: Well surveying devices
IPC: E21B47/022
Filed: 1930-08-19
Abstract: 360,523. Borehole clinometers. JACKSON, L. MELLERSH-, 28, Southampton Buildings, London.-(Sperry-Sun Well Surveying Co. ; 1608, Walnut Street, Philadelphia, U.S.A.) Aug. 19, 1930, No. 24834. [Classes 97 (ii), 97 (iii), and 98 (i).] For effecting a survey of boreholes a casing adapted to enter the borehole and containing a camera for simultaneously photographing means for indicating deviations of the casing from the vertical position and gyroscopically controlled means for indicating a determined azimuth contains an electric power supply for operating both the gyroscope and camera. In the form shown, the recording instruments are enclosed in a casing 6, Fig. 1, supported by buffer springs in an outer casing comprising two separable parts 2, 4. A swivel 10 at the top of the part 2 is connected to the cable 12 by which the device is lowered into the borehole. To minimize shock the lower end of the part 4 is provided with a resilient nose 18. Fig. 2 shows the gyroscopic apparatus mounted in the lower part 22 of the casing 6. The vertical ring comprising the two halves 110, 117 insulated from each other at 118 is supported in the bearings 115, 115a by stems 109, 119. The stem 119 rests on a ball 120 and dips into a quantity of mercury 122. The stem 109 carries a cup 108 containing mercury 107 into which dips a spring wire connected to the terminal 106. A pointer 104 moving over the dial 103 is fixed to the cup 108. The electric current for driving the gyroscope passes to the axles @ the gyro casing via terminal 106, stem 109 and the half 110 of the vertical ring and via the terminal 121, stem 119 and half 117 of the vertical ring. Fig. 6 shows one of the bearings for the gyro casing. The thimble 127 threaded in the vertical ring contains the antifriction bearings 128 and a ball 129 at the end of the stub shaft 125 to take up end play. A shunt path for the current, comprising a light spring 130 connected at one end to the stub shaft 125 and at the other end to a ring 131 adjustably mounted in the vertical ring prevents possible sparking at the bearing. To take up end play in the gyro rotor bearing (not shown) a spring washer presses against the outer race of the ball bearings The upper part 28 of the casing 6 contains a level comprising a glass box 54 containing a mixture of ethylene glycol and water and having a spherical surface 56 provided with concentric circular marks. A bubble indicates the inclination with reference to the concentric circular marks. An expansion chamber 60 is provided. Several levels having various ranges may be used. Camera mechanism arranged between the gyroscope and level is driven by the motor 66. The film 72 which may be sensitized on one or both sides is intermittently drawn across the exposure aperture by geneva mechanism 68. Two lenses on opposite sides of the film project an image of the level 54 and an image of the pointer 104 respectively. The exposures are effected by a rotating contact wheel 86 which intermittently closes the circuits of lamps 90 and 64, illuminating respectively the indications of the gyroscopically stabilized member and the opal glass plate 62 above the spirit level. The indications of a chronometer are recorded with the pointer 104 thus enabling the depth at which the records were made to be calculated from a knowledge of the length of cable paid out at the time recorded. Fig. 14 shows a device for indicating the length of cable paid out at different times. The cable 12 engages a measuring pulley 170 which drives a counting device 172 and is also geared to a shaft 176. The latter carries a commutator 178 which closes the circuit of an electromagnet 188 with each revolution. The armature 190 carries a stylus which records the revolutions of the pulley 170 on a uniformly moving record strip 192. Alternatively the record strip may be driven by the pulley 170 and time indications stamped thereon at intervals, or a series of photographs of the counter 172 and a chronometer may be taken. In a modification, a pressure gauge comprising a pressure sensitive coiled tube carrying a pointer and communicating with the exterior through a flexible diaphragm may be included in the main casing, its indications being recorded with those of the level. The pressure gauge may be graduated directly in terms of depth.