Patent GB-678410-A (GB)
Title: Fuel indicating system
IPC: G01F15/075
Filed: 1950-05-31
Abstract: 678,410. Electric indicating systems. BENDIX AVIATION CORPORATION. May 31., 1950. [June 29, 1949] No. 13635/50. Class 40 (i). The fluid used or remaining in a reservoir feeding several engines is indicated by means of meters responsive to the rate-of-flow of fluid from the reservoir to the respective engines, the meters actuating Selsyn transmitters connected sequentially to a receiver adapted to actuate a totalizer according to the average fluid consumption. As shown, for totalizing the fuel consumption of eight engines and subtracting this amount from the amount originally in the tanks to give a continuous indication of the remaining fuel, a rate of flow meter 12 in the fuel supply pipe 14 to each engine, drives, through an associated Selsyn transmission system 10, 28 a corresponding remote pointer 32 to indicate the rate of fuel consumption of the respective engine. The eight Selsyn transmitters T1 ... T8 for the respective engines, only one of which T1 is shown in detail, are also connected in turn by a sequence switch 40, 42, 44, 46 driven at constant speed by a motor 48, to a differential Selsyn 35, in the even positions of the switch. Thus, as shown, in position 2 of the switch, the stator 34 of the differential Selsyn 35 is connected in parallel with the stator 26 of transmitter T1. The rotor 50 being held stationary for the time being, an error voltage is induced in the rotor 56 of Selsyn receiver 54 corresponding to the fuel consumption rate of engine No. 1. This error signal is amplified at 60 and in known manner actuates a motor 66 in the follow-up direction to advance the rotor 56 to the null position. At the same time, the counter 75 which is initially set to indicate the total fuel contents of the supply tank, is set backwards by the motor 66 an amount corresponding to the fuel flow to engine No. 1 for the period taken by the sequence switch to make one revolution, i.e. about 16 seconds. In the next position of the sequence switch (odd contact No. 3) two phases of the stator 34 of the differential Selsyn 35 are connected to line to produce a stationary reference field therein and the error voltage induced in the stationary receiver rotor 56 is used to drive the motor 72 to advance the rotor 50, by an amount corresponding to that of the setting of rotor 56, so that in the next position of the sequence switch the rotor 56 will be advanced a further amount corresponding to the fuel consumption of engine No. 2 over the 16 second period and this amount subtracted from the "remainder" counter 75. In this way the "remainder" counter is set back successively in the even positions of sequence switch corresponding to the fuel consumption of the respective engines and in the odd positions the differential Selsyn rotor 50 is advanced corresponding to the preceding advance of rotor 56 so that the latter will add the "fluid flows" of the various transmitters. Alternatively, the rotor 56 could be reset to a zero position instead of setting the rotor 50 but in this case a unidirectional drive to the counter 75 would be required. Each motor 66, 72 drives a rate generator 82, 76 which is connected in known manner to the amplifier input when the associated motor is operative, to prevent hunting of the respective motors,