| 摘要 |
<p>869,524. Automatic temperature-control systems. ROBERTSHAW-FULTON CONTROLS CO. Feb. 10, 1958 [April 29, 1957], No. 4320/58. Class 38 (4). The temperature of a heated space 12.is kept constant by the use of an annular chamber 15 containing electrically conductive material melting at the desired temperature, and the conductivity of which varies with the liquid: solid ratio of the slurry. A coil 54 would on a toroidal former is immersed in the material so that the latter forms in effect a single-turn secondary winding, the varying impedance of which is effectively reflected into the primary winds to affect the balance of a bridge circuit formed by resistors 48 and 50 and inductances 52 and 54. The bridge is arranged so that unbalance at a 1 : 1 liquid : solid ratio acting through a power amplifier 36 provides enough energy for a heater 42 to maintain the desired temperature ; a variable resistance 62 reflecting an impedance into the primary of transformer 58 provides adjustment for the bridge balance.</p> |
