GB406648A - - Google Patents

Abstract

406,648. Turbidometers. KIDDE & CO., Inc., W., 140, Cedar Street, New York, U.S.A. Aug. 25, 1932, No. 23774. Convention date, Nov. 11, 1931. [Class 97 (iii).] Relates to installations for detecting smoke or suspended matter in fluids of the kind comprising a plurality of conduits for leading fluid from individual areas, means for maintaining a continuous fluid flow through the conduits, a detecting device, and means for connecting the conduits successively to the detecting device ; and consists in the provision of visual observation means in the individual conduits. The conduits 10, Fig. 1, are connected to a chamber 12 from which a pipe 13 leads to a suction fan 14. A member 29 adapted to be rotated in the chamber 12 by an electric motor 16 is provided with a passage 30. As the member 29 rotates, it successively connects the conduits 10 with a pipe 31 leading to a smoke-detecting device. This comprises a light source 39 and a selenium cell 41, passage of smoke across the light beam causing the cell to be illuminated by reflection. The exhaust of the fan 14 is passed to the chamber 38 enclosing the light source, for cooling purposes. Each conduit 10 is provided with a window 58 and an upward extension 59 furnished with a reflector 60. The latter reflects light from a source 61 down the conduit, so that smoke can be observed through the window. In a modification, Fig. 6, means is provided for interrupting the drive of the member 29 when smoke is detected. The member 29 is driven from the motor 16 through a friction clutch 17, 18 normally held engaged by a spring 19. The clutch can be disengaged by linkage from the armature 26 of a relay 25 when the latter is energized upon the detection of smoke. When this occurs, the clutch member 18 is braked by a surface 28, arresting the member 29. The latter is provided with a skirt 35 which can be observed through a window to ascertain which conduit was connected to the detecting device when smoke was detected. Fig. 8 shows an arrangement of circuits for use with the installation shown in Fig. 6. The voltage fluctuations caused in the circuit of the selenium cell by the incidence of light upon the cell are imposed on the grid of a thermionic valve 46, the plate circuit 47 of which includes a relay winding 48. The relay comprises three circuit contacts 49-51. The contact 51 closes a circuit through the winding 48 and a battery 53, so that the relay continues to be energized although the plate current due to smoke detection is momentary. Contact 50 closes the circuit 55 of an alarm bell 56, and contact 49 closes the circuit 57 of the relav 25. The relay 48 can be deenergized by a manual switch 54, restoring the member 29 to activity. Specification 399,449 is referred to. The Specification as open to inspection under Sect. 91 comprises also an arrangement similar to that shown in Fig. 6, but without provision for visual inspection of the fluid streams. This subject-matter does not appear in the Specification as accepted.