| 摘要 |
<p>579,928. Electric control systems. LANDIS & GYR SOC. ANON. Aug. 11, 1943, No. 13003. Convention date, Aug. 13, 1942. [Class, 40 (i)] [Also in Groups XXXV and XXXVII] A physical magnitude such as temperature, fluid pressure, mechanical force, or moisture is automatically controlled in dependence on another magnitude by the aid of a Ferraris instrument responsive differentially to the two. magnitudes and co-operating with a periodically operating auxiliary member causing selective operation of contactors according to the sense of the differential response. The invention is described as applied to a system controlling the temperature of a building in accordance with the relation between the temperature outside and the temperature of a heating fluid. The disc 20 of the Ferraris instrument is driven by the voltage coil 1 and a coil 2 the current in which varies between positive and negative values according to the condition of balance of a Wheatstone bridge comprising resistance elements responsive to out-door temperature and to the temperature of the floor pipe of a heating boiler; this bridge may also include a resistance to modify the wiring for night conditions. The disc carries a pin 21 which is adapted, on displacement of the disc by unbalance, to engage a contact member 13 or 14 whereby its further movement is prevented. A roller 23 on an arm 22 carried by a slowly rotating shaft periodically engages the pin 21 whereby a circuit is closed at contact 13 or opened at contact 14 according to the position of pin 21. The circuit of a motor operating temperature regulating means, such as a boiler damper, includes the normally closed contacts 16 of a relay which is energized to stop the motor when contact is made at 13. The reiay circuit includes a maintaining contact 17 and the contact 14; when contact 14 is opened the relay is de-energized and the motor again operates. In a modification the coil 2 is in two opposed parts one of which is in series with a fixed resistance and the other in series with the temperature response resistances. The Specification as open to inspection under Sect. 91 describes also an arrangement, Fig. 4 (cancelled), in which pins 27 circumferentially arranged on a Ferraris disc 25 successively engage a leaf spring 26 carried by a weighted lever 28 and normally engaging an abutment 29 carried by the lever, so that in one direction of movement the spring is lifted from the abutment without moving the lever as each pin is driven past it but in the other direction the lever is actuated to lift the lever. The lever normally impinges upon a spring contact arm 32 to hold open a circuit which is closed when the lever is lifted. This subject matter does not appear in the Specification as accepted.</p> |
