GB502971A - Improvements in means for detecting the presence of suspended matter in fluids - Google Patents

Abstract

502,971. Photo-electric apparatus for detecting suspended matter in fluids. BRITISH ELECTRICON (LONDON), Ltd., ROBINSON, W. A., and CHAMBERS, W. A. Sept. 28, 1937, No. 26257. [Class 40 (iii)] Relates to photo-electric apparatus of the kind in which a photo-electric cell normally in the dark becomes illuminated when a fluid passing through a lighted chamber contains particles of suspended matter, the illumination of the cell being due to reflection or refraction by the suspended particles, for example as described in Specification 272,914, [Class 40 (v)]. According to the invention, the fluid conveying installation together with the light source and the light-sensitive device form a stationary system, and an optical travelling unit is provided to scan a number of fluid streams in succession, a distributing switch device being moved at the same time to connect the corresponding signal circuit to the amplifier controlled by the photo-cell. As shown in Figs. 2 and 4, a number of chambers 3 are disposed around a rotary scanning device 15 and are supplied with fluids by a number of pipes 2. The fluids are discharged through outlets 9 to an upper space 7 and then through outlets 10 to a hood 11 connected to an exhauster (not shown); or the fluids may be led from the chambers 3 directly to the hood 11. The chambers are illuminated by electric lamps 13 directly below bottom openings in the chambers 3. The rotary scanning device 15 contains a reflector 18 and is carried by an insulating disc 19 provided underneath with a contact piece 25 adapted to bridge pairs of contacts 28, 29 in succession as a window 16 in the scanning device comes opposite a window 8 in a chamber 3. In this position of the scanning device, if the fluid in the chamber 3 is clear, no light is received by the scanning device ; but if the fluid contains suspended matter, light therefrom passes into the scanning device and is reflected through a window 17 on to a photo-cell 31 in an opaque casing 30. This cell is connected to an amplifier 45, Fig. 5, which operates a relay 44 to close a contact 43 when light strikes the cell. This completes the circuit of the drop indicator 39 corresponding to the contacts 28, 29 bridged over by the contact piece 25, thereby indicating the particular chamber 3 in which there is matter in suspension. At the same time, a relay 42 closes the circuit of a main power alarm. As shown in Fig. 5, the circuits of the signals 39 are fed from one source A, and the amplifier 45, the lamps 13, and the motors 23, 24 for driving the scanning device are fed from mains 34. Two driving motors 23, 24 are provided, so that one can act as a stand-by. In a modification, Fig. 6, two cells 31, 51 are used in conjunction with two reflectors 18, 18<1> and two windows in the scanning device. These cells may be used at the same time' to check each other; or one may be switched out to act as a stand-by.