| 摘要 |
<p>438,195. Servomotor control systems. REAVELL & CO., Ltd., and HUMBY, A. J. D., Ranelagh Works, Ipswich. April 13, 1934, No. 11193. [Class 135] Apparatus for regulating physical values such as temperature, humidity, density, water level, &c., where only very limited power is available for operating the regulator comprises means for producing operation of an all electric transmission gear of the kind employed in Specification 265,012, [Class 40 (i)], with which is combined a relay adapted to operate means for producing a modification of the prevailing conditions. For controlling the temperature of a stream of fluid in a duct 1 a valve 4 is controlled to vary the admission of a cooling fluid. A thermocouple 3 produces a very small current in an electric coil 7 which moves a contact pointer 6 to make contact with either contact 15 or 16 of another pointer member 8 which closes either the forward or reverse circuit of a motor 13. The operation of the motor 13 alters a resistance 17 in an electric circuit 18 and therefore the current flowing in the said circuit, which current passes through a follow-up coil 9 attached to the contact pointer 8 which brings this pointer into a corresponding position to that of the pointer 6, i.e. a position where the pointer 6 is midway between the contacts 15, 16 of the pointer 8, so that the motor circuit is broken and the motor stops. Thus the position of the contact pointers 6, 8 and the current flowing in the circuit 18 are functions of the temperature in the duct 1. The current in the circuit 18 is utilized to operate a core 20 of a solenoid 19 which operates a relay in the form of a pivoted jet pipe 21 supplied with fluid under pressure to operate a servomotor 5 connected to the valve 4.</p> |
