METHOD OF PROTECTION OF NETWORK OF WATER SUPPLY SYSTEM OF INDUSTRIAL UNDER- TAKING AND POPULATED AREA AGAINST POLLUTION Russian patent published in 1997 - IPC

FIELD: undertakings of medical, microbiological, chemical and other industries consuming water of drinkable quality from town network and other sources for drinking and production purposes in which production cycle there are circulated harmful substances. SUBSTANCE: method is based on prevention of countercurrent flow of water from undertaking network with fall of pressure in town network. This is achieved by installation of check valves at inlet of town water supply system to undertaking and across each branching from it to technical needs inside buildings. Reliability of protection is increased by duplication of operation of check valves, by formation of buffer zones in pipe-lines with positive pressure, and other measures. Relays of pressure difference are cut in parallel to check valves upstream and downstream of them. With emergence of situation when pressure downstream of check valves exceeds pressure upstream of them relays generate pulses in the form closing of electric contacts which are converted to light and audio signals-commands by which shut-off fixtures installed after check valves are cut off manually or by automatic means and positive pressure, for instance, compressed air is supplied to zones between them. EFFECT: increased reliability of method. 2 dwg