| 摘要 |
1,235,236. Photo-electric monitoring. HONEYWELL Inc. March 28, 1969 [March 28, 1968], No. 16316/69. Heading G1A. [Also in Divisions F3-4 In an apparatus responsive to a condition which may alternatively be the presence or absence of radiation, a sensor which is rendered responsive to incident radiation from a first or second direction according to its mode of energization and energized alternately in the two modes, is used, and radiation or an absence of radiation simulating the condition being monitored is applied from the direction other than that being monitored in order to provide a check on its operation. The sensor may be a two or three electrode ionization type device and polar diagrams of such devices are described. The arrangement may be used to monitor a flame and control the fuel supply to a burner, in which case the simulated condition (absence of radiation) may be achieved by a structural barrier or blackening the side of the sensor, or it may be used for example to detect the presence of particulate matter in the atmosphere which reflects light on to the sensor. In the arrangement Fig. 4 ultraviolet light from a lamp 30 is applied to the sensor 10 from one direction via a mirror 38 and around the lower edge of a barrier 32 and when the sensor is energized in the other mode light reflected through window 45 by particulate matter in conduit 43 is incident in the other direction. A fuel control circuit for a three electrode sensor in which contacts of relays on the two parts of the sensor are in series in the fuel valve control line is described. |
