Patent EP-2113722-A2 (EP)
Inventor: LABRUNA UMBERTO
IPC: F24D19/10
Filed: 2009-04-22
Abstract: The field of application of the invention is the distribution of hot water for sanitary uses with an optimal temperature between 48 and 50 ° Celsius in all (previously existent and/or new) hydraulic systems after it's centralized, high temperature production by any known means of heating at temperatures of 70° Celsius and above in order to disinfect the incoming water supply from any traces of the Legionella Bacterium and the associated risk of human infection. 
     The essential characteristics of the invention consist in the technically common use of the process of continuous, high temperature thermal disinfection at temperatures of 70° Celsius and above applied to the incoming water supply in order to rid it of the risk of human infection associated with the presence of the Legionella bacterium with the addition of an innovative system which preserves the disinfection until human use takes place, even though a sensible drop in the distribution temperature occurs. This system constitutes the subject of the present invention. 
     The following text refers to the attached drawing entitled " Fig. 1/1 ": 
     The hot water for sanitary uses is produced in an accumulation boiler  Fig. 1/1(T)  which is set at temperatures of 70° Celsius and above in order to disinfect it from the Legionella bacterium. The hot water produced is fed to the system through  Fig. 1/1(G)  and, by transiting in the secondary circuit of a plate based heat exchanger  Fig. 1/1(SC)  which comprises an automatic temperature control  Fig. 1/1(VMA)  placed on it's primary stage that is fed by the cold water from the incoming water supply and is then cooled to the optimal distribution temperature of 48-50 °Celsius before being supplied to the main feed of the sanitary water network  Fig. 1/1(M)  in a condition of total and certain absence of live Legionella bacterium. 
     The invention is completed by; the automatic temperature regulation of the water recycle Fig. (VMR) which avoids overheating in case of lack of use, the pump system  Fig. 1/1(X) - Fig. 1/1(Y)  which avoids any risk of temperature layering in the boiler's reservoir, the security block on the sanitary waters  Fig. 1/1(TS) - Fig. 1/1(VS)  and the alarm equipped temperature monitoring system  Fig. 1/1(TA)  which signals if the temperature falls below 70° Celsius, the two inspection taps  Fig. 1/1(RU) : one for system discharge and the other for obtaining water samples for analysis and the included electrical control panel  Fig. 1/1(QE) . 
     The present technology, while utilizing continuous high temperature disinfection at temperatures of 70° Celsius and above, is then rendered useless by the method generally used to cool the waters before their actual use by physically mixing the hot, disinfected waters with the incoming cold water feed from the main water supply thus exposing the resulting waters to the risk of infection by live Legionella bacterium potentially present in the main cold water feed. 
     Such bacterium, through the heating provoked by the physical combination of hot and cold waters, awakes to a state of momentary quiescence that causes its development, proliferation and, successively, the colonization on its behalf of all waters comprised in the hot water distribution segment of the entire hydraulic system, thus rendering useless the previous disinfection which took place in the boiler's reservoir at temperatures of 70° Celsius and above and renovating the high risk of human infection due to the survival of live Legionella bacterium.