GB1380019A - Water treatment system - Google Patents

Abstract

1380019 Cooling towers PARKER ENGINEERED CHEMICALS Inc 17 May 1973 23509/73 Heading F4K [Also in Division G3] In a system for treating water which is recirculated by means of a pump 12 through the heat exchanger of a refrigeration unit 14 in an air conditioning system and then through a cooling tower 11, a water level detecting device 42 is provided to control the addition of fresh make up water to the sump 15 of the tower to keep the level in the sump at a predetermined value. The detecting device 42 comprises a plurality of electrodes 50 suspended at different levels in a container 45; the electrodes include a pair of primary low and high level electrodes 50a and 50b connected to electric control circuitry 65 and a pair of secondary low and high level electrodes 50c and 50d connected to control circuitry 66. During normal operation the primary circuit 65 including electrodes 50a and 50b serves to control the addition of make-up water via conduit 39 and solenoid valve 41. In the event of the primary circuitry 65 malfunctioning and failing to call for make-up water, the secondary circuit 66 including electrodes 50c and 50d functions to take over control of the water level in the sump 15. A chemical feed control system (104, Fig. 2B, not shown) functions to automatically or manually operate diaphragm pumps 31a, 31b and 31c each time make-up water is added to the sump. The pumps serve to inject slugs of chemical compounds, e.g. scale and corrosion inhibitors and an algaecide, into a dilution chamber 29 located in a by-pass conduit 26, the recirculated water on leaving the chamber 29 being passed back to the inlet side of pump 12. A drain valve 28 is provided to remove a portion of recirculation water from the system on some or all the occasions that make-up water is added to the sump 15.