Patent GB-546655-A (GB)
Title: Method and apparatus for surveying wells
IPC: E21B47/022
Filed: 1941-01-31
Abstract: 546,655. Bore-hole clinometers. JACKSON, L. MELLERSH-. (Sperry-Sun Well Surveying Co.). Jan. 31, 1941, No. 1320. [Class 97 (ii)] A bore-hole clinometer comprising a casing and a pendulum within a casing is provided in the casing with a record member adapted to be marked by the passage of a current, the current flowing for a considerable period between the pendulum and the record member to mark the latter. As shown in Figs. 2 and 3 the outer casing 1 encloses an assembly comprising connected units 3 ... 7. The lowest unit 3 is provided with a chamber 10 and float 11 having a stem 12 the upper part of which is guided in a plug 15 screwed in a boss 16 and forming a chamber 20 with apertures 25. The chamber 10 is provided with apertures 8. The unit 4 is connected to the unit 3 and forms a chamber 27 containing a liquid such as kerosene up to the level of the apertures 28 and a compass 30 is suspended on a pivot 31 secured to the plug 15. The top of the unit 4 is closed by unit 5 and an insulating disc 35 in which is mounted a yoke 38 to which is pivoted by means of gimbals a pendulum 40. The pendulum is provided with a chamber 41 having a float 43 to which is secured a needle 44 as shown. Unit 5 contains one or more batteries 50 one pole of which is connected to the metallic assembly by a spring 51 while the other is connected to the pendulum by washer 52, spring 53 and pin 55 passing through an insulating plug 56, and yoke 38. Unit 6 secured to the top of unit 5 comprises a chamber 60 having two tubes 78, 79 of unequal length projecting thereinto and an outlet passage 62 communicating with a cross passage 70 the passage 62 being of such size as to determine the time flow of the liquid from chamber 60 the level of the liquid in the latter chamber being determined by the length of tube 79. A filter 63 and strainer 66 are provided. The unit 7 comprises an inverted chamber and is secured to unit 6 by a plug 75. In use the casing and assembly filled as shown are lowered to the desired depth meanwhile the liquid in chamber 60 passes through passages 62, 70 to the annular space between the casing and assembly and eventually enters the float chamber 10. The float 11 is thus raised causing a valve 22 to lift off its seat and permit liquid from the chamber 27 to flow into chamber 10. As the level of liquid descends the float 43 in the pendulum also descends until the needle 44 contacts the record card of the compass 30 to permit the current to mark it. Liquid meanwhile continues to flow from chamber 7, eventually entering chamber 27 through apertures 28 causing the float 43 of the pendulum to rise again and remove the needle 44 from contact with the card so disconnecting the current. The clinometer may then be raised. The record card may be a composite one of metal foil and cardboard placed on the compass needle disc in which case the electric current punctures the card. In another case the card may be a paper one moistened with an electrolytic so that a discoloration is caused at the point of contact. In a modification no battery is employed the moistened card serving as the electrolyte of a cell in which the needle 44 and compass needle disc of different metals form the poles.