| 摘要 |
<p>1,185,972. Photo-electric burner control. HONEYWELL Inc. March 12, 1968 [March 15, 1967], No. 12022/68. Heading G1A. [Also in Division F4] A burner control system includes Geiger tubes 21, 22 acting as flame sensing devices coupled into opposite sides a-b-c, a-d-c of a bridge circuit of which the other arms include the coils A, B of relay having contracts A1, B1 and responsive to the state of the Geiger tubes a third relay coil C being connected between points b, d to detect difference in state between the tubes 21, 22 by becoming energized when the bridge is unbalanced and thus indicating malfunction through a circuit 14 by closing contacts C2, C3 while the supply of electrical energy to the burner installation is discontinued by the opening of contacts C1, C3. The presence of flame with both tubes functioning normally causes the burner installation to be energized through terminals 11, 12. A modification Fig. 2 includes two silicon controlled rectifiers 23, 24 connected in parallel and two impedances in the form of resistors 25, 26 develop voltage signals supplied to the gates of the rectifiers to cause them to conduct or not according to the response of the tubes 21, 22. In a further modification Fig. 3 (not shown) a single silicon controlled rectifier is included in the supply circuit and has its gate coupled to point d of the bridge.</p> |
