Patent GB-499400-A (GB)
Title: Means for measuring the quantity of liquid contained in a tank
IPC: G01F23/16
Filed: 1937-06-18
Abstract: 499,400. Measuring cubical contents. ODIER, A. I. June 18, 1937, No. 17019. Convention date, June 19, 1936. [Class 106 (i)] The quantity of liquid in a tank is determined by measuring the volume of free space remaining in the tank. The invention comprises means for introducing into the tank a fluid under pressure from an exterior source until the pressure within the tank is increased up to a predetermined constant value, means for causing the pressure within the tank on reaching said predetermined value to interrupt further introduction of fluid, and means for measuring the quantity of fluid under pressure introduced into the tank which quantity is inversely proportional to the degree of filling of the tank. As shown diagrammatically in Fig. 1, a tank 1 is connected to an air pump 2 actuated by an electric motor 3 put into operation by a source of current 4 through closure of a switch 5. A pressure gauge 6 connected with the tank is adapted to open the circuit when the initial pressure in the tank has increased by a predetermined amount. The amount of air admitted is shown by the pointer 7 of an indicator driven by the pump. A mechanical arrangement is shown in Fig. 2, with the tank 11 connected to a cylinder 12 in which works a piston having a rod 17 formed with a rack to drive an indicating pointer 19. The piston is arrested, on a predetermined pressure being reached, by a finger 14 on a lever 13 operated by an aneroid chamber 15. A practical embodiment for a tank of an aeroplane is shown in Figs. 4, 6, 7 and 8 ; a cylinder 26 is provided with a piston 27 carried by a splined axle 30 secured to a supporting member 31. The member 31 is rigidly connected to rods 32 secured to a control member 33 and knob 34. The rods are formed with racks that mesh with pinions 35 on a shaft 36 acted upon by a spiral spring 37 and formed with a worm gear to drive a shaft 38. On the shaft 38 is mounted an arm 40 that co-operates with a pin 44 on a dial 42 secured to a pivot shaft 41 and controlled by a spiral spring 43. On pivots 47 is mounted a plate 46 carrying an aneroid chamber 45 that is in constant communication with a tube connecting the tank to be measured with a fitting 48 on the cylinder. Deformation of the chamber 45 is transmitted by a finger 49 and sector 50 to a pinion that carries a pawl 51 adapted to co-operate with teeth on a ring 52 secured to the dial 42. A second aneroid box 54 in the cylinder is fixed to a plate 55 so that variation of pressure displaces a rod 56 to adjust the point of contact of a ball 57 with the plate 46. In a modification an auxiliary tank of fixed volume may be provided in which air under pressure is admitted up to a predetermined pressure. This tank is connected to a pressure gauge and to a pressure reducer or expander connected with the tank and adjusted to cut off the air flow immediately a given fixed overpressure is attained in the main tank. Where very small volumes are concerned a pump as shown in Fig. 11, may be provided. This pump comprises a casing 61 with two bores 62, 63 in which can rotate cylinders connected by gear teeth 64 and formed with three openings for the reception of articulated pistons 65 connected in pairs. The bottom of each cylinder is grooved for communication with the inlet and outlet fittings. If cylinder 63 acts as a motor, cylinder 62 acts as a receiver to drive a shaft connection 68. Reference has been directed by the Comptroller to Specification 478,502.