Patent GB-571613-A (GB)
Title: Improvements in and relating to apparatus for determining variation in the force of gravitation applicable also for ascertaining latitude and for controlling or measuring temperature or pressure
IPC: G01V7/00
Filed: 1943-10-04
Abstract: 571,613. Determining force of gravity. MOORE, S. BRAMLEY-. Oct. 4, 1943, No. 16264. [Classes 97 (ii) and 97 (iii)] [Also in Group XIX] An apparatus in which variation in the force of gravity is indicated comprises a float completely or partially immersed in a liquid or liquids, supported partly hydrostatically and partly magnetically in balance so that any variation in the force of gravity will upset the balance and cause the float to move, the direction of movement indicating whether the variation is plus or minus. Fig. 5 shows a typical apparatus whereby any alteration in the force of gravity and hence any alteration in the latitude of a ship's course can be detected. An air-tight container C with glands G<1>, G<2> to prevent leakage of air from the air-space A<2> and volume control rods V<1>, V<2> operated by hand wheels L<1>, L<2> has incorporated in the lower part of its side walls an annular permanent magnet N and contains mineral oil F<2>. The float is completely submerged in the mineral oil F<2> and comprises an annular chamber containing ethyl benzoate and a central chamber containing mineral oil F<1> which is in communication with the oil F<2> by the magnetised tube T<1>, the chambers having a common air-space A<1> above the liquids they contain and an annular permanent magnet M which forms the side wall. The force of magnetic repulsion between the magnets M, N reinforces the buoyancy of the float. When gravitational latitude alters the float will sink when the ship's course veers to the north and closing of the circuit comprising the electromagnets T<3>, T' and trembler E<2> will light an indicating lamp and the float will rise when the course veers to the south and closing a similar circuit T<1>, T<2>, E<1> will light a lamp of a different colour, the energized electromagnets T<2> or T<4> in conjunction with its corresponding permanent magnet T' or T<3> also tending to repel the float back to its original central or balanced position, the volume control rods V<1>, V<2> being adjusted to show the new latitude. Fig. 6 shows a modification in which any variations in temperature at any particular latitude are automatically controlled and comprises a magnet Q, Q<1> floating in the oil F<2> and having an air-space A<3> above it. Variation of temperature alters the position of the floating magnet Q, Q<1> and therefore its magnetic repulsion to the magnet Q<2> on the main float. Variation of pressure such as atmospheric pressure at all latitudes is compensated by a double chamber A<4>, A<5> having oil F<3>, F<4> in communication and in the chamber A<4> is floated a magnet H so that differences of pressure between the container C and the atmosphere vary the oil levels in the two chambers and consequently the position of the magnet H which in conjunction with magnets H', H<2> and tremblers D<1>, D<2> completes an electric circuit to vary the temperature of a bath surrounding the container C and consequently the pressure within the container. The apparatus shown in Fig. 5 may be used to measure pressure inasmuch as after the float is balanced the new pressure from say a vessel is admitted to the air-space A<2> and the float is rebalanced by means of the volume rods which now will register pressures. The same apparatus may be used to measure changes of temperature. In this case the apparatus has only one liquid, viz. ethyl benzoate, variations of temperature of which vary the buoyancy of the float and destroy its balance. The balance is restored by the volume rods which now will register temperatures.