| 摘要 |
<p>1,078,531. Fluid regulation; pure fluid amplifiers. BOWLES ENGINEERING CORPORATION. July 6, 1964 [July 5, 1963], No. 27723/64. Heading G3H. A fluid control system for controlling the flow of air to actuate an air turbine 1 to maintain a constant speed comprises a fluid analogue amplifier 11 having a main jet 15 and control orifices 12, 13 supplied from a fluid source. The control signal at orifice 13 is controlled by a tuning fork 21, the fluid supply being connected to an annular outlet 19 whereby a negative pressure is developed across a leg of the fork during a portion of the cycle so that the supply both drives and damps the vibration of the fork. The signal at orifice 12 is controlled by a toothed wheel 4, driven at engine speed, which controls a supply of fluid from a source 7 whereby flow from the outlet 8 is restricted or not by the application or absence of the source 7 to the outlet 8. The frequency of the pulses at 12, 13 produce a predetermined difference at the required engine speed and the outputs at 22, 23 are at half the frequency difference. These signals pass to a full-wave rectifier 24 having an output 28 which is the higher pressure of the inputs 26 and 27. The signal 28 passes through a capacitor 30 and low pass filter 29 which comprises two tapered passages 31, 32 connected by passages 33 which are sufficiently narrow to serve as fluid inertances as well as resistances. The filter is tuned to a frequency, somewhat above the desired frequency difference and damps out high frequency signals. The frequency modulated signal appearing at the outlet 34 is fed to a frequency discriminator 36 by branch lines 39, 41. The pressure signal 39 acts on the flow from a supply 42 through a line 43 to a capacitor 44 which form a resonant circuit, the output at 51 being dependent on the pressure at 39 which deflects the flow. The output 51 leads to a control orifice 52 of an amplifier 53 in opposition to an orifice 54 supplied from the source. The outputs 57, 58 lead to a rectifier 61 which has the higher pressure as an outlet and this is connected through a capacitor 63 to a control nozzle 64 of an amplifier 68 whose other control nozzle 66 is connected to the second output 38 of the discriminator. The outputs 69, 71 provide a feedback through capacitors 73, 77 and also lead twin unit 84 which comprises output channels (86), (87) Fig. 3 (not shown) on either side of a dump (102) and control channels (82), (83) connected to the outputs 69, 71. The unit 84 is designed so that its output is equal to the square of the input and the outputs (86), (87) are relatively small compared with the channel (102). The curve shown represents the distribution of the stream and the exponential part of the curve are used for the outputs (86), (87). The outputs are connected to opposite sides of a piston 92 which adjusts the valve 2 controlling the air supply to the turbine.</p> |
