level detector of the mud water interface in waste water treatment

摘要

The detector head is immersed by suspending it from a service tube which extends clear of the tank. The head is in the form of a ring on a horizontal axis and with an open centre through which liq. can pass. The annular body of the ring houses diametrically opposed emitter and receiver for luminous waves outside the visible spectrum, partic. infra-red waves and esp. those of wavelength between 0.90 and 15 microns. Clean water is continually flushed across the effective faces of the emitter and receiver. The ring is pref. made of a synthesic plastic and passages are formed in the ring body for connection to the emitter and receiver from the service tube, as well as clean water passages to carry water from the service tube. Used for monitoring the sludge level in a waste water sedimentation tank, partic. a secondary sedimentation tank, where the sludge is of low density. Waste water treatment is regulated w.r.t. to sludge level. Algae and vegetable growth is destroyed, by infra-red radiation, so the probe does not become fouled up.