[1]United States Patent - @Office 21792,181 2,792,181 CIRCLTITS FOR TBERMAL HE r ATING PLANTS Innocenzo Cialente, Turin, Italy Application August 14, 1950, SeriaI No. 179,161 Claims priority, application Italy August 16, 1949 10 3 Claims. (Cl. 237-63) This invention relates to thermal plants for heating, of 15 roo ms and premises and for technological elaborations, and its object is a novel type of circuit which use enables a considerable reduction of the weight of the needed material @to be effected, said reduction in turn involving a redu ction of the total cost of the plant while the installa- 20 tion of the same plant is simplified, @ notable saving of cost of labour bein- also achieved. It is @vell k-.iown to those skilled in the art that thermal plant s are divided into two main classes, i. e. water-plants and steam-plants. The plants of the first named type, 25 whic h are geiierally the most used, present several drawback s, s-Lich as the heavy weight of the material used (heat ing surfaces, pipings, etc.), difficulties for a central coqtrol of 'Cne plant in order to supply heat in the upp er floors of very hi,-h buildings, difficulties in con- 30 necti n.- remote plants with a single thermal source, and so on. The plants of the second type, which are confined ,to n,@i:ticiilar cases of use of producin.- steam, present likewise no light drawbacks, though their weight, by reas on of the circulating speed and of the snialler mass 35 of employed fluid, is noticeably inferior to that of the corr espondin,@ hot-water plants. Also, it is well known ',hat a central coiitrol of -the plant during different seasons is difficult to maintain and one must have recourse in such plants, to th.- einployment of several differeni 40 fittin gs, wh:lch structure and service require a rather careftil management. In order to profit at once from the advantages of the two types of plants, some layouts of circuits intermediate 45 betw een said extreme types have be-.n proposed, according to which a fluid, gen-,rally water, is employed which is heated and maintained at a temperalure greater than the boiling -temperature at normal pressure, i. e. for the wate r, to a temperature beyond of 100' C. (212' F.). 60 Said circuits have not been adopted, for several reasons, nam ely, the necessity for employing skilled persons, latent dang er in the servicing of said circuits, and the periodic insp ection and control by authorities in the building trade. It is an object of the present invention to eliminate 55 the drawbacks encountered with said transition network layo uts, by means of a novel type ol' circuit, in which an intermediary fluid is used, which is heated to a tempera ture greater than the boiling temperature at atmospher ic pressure; in said circuit the fluid can be circulated Go solel y by the difference o'L density between hot and cold fluid, or by a pump; the devices intended to utilise the heat energy are connected in a single circuit, the fluid trav eling in said devices gradlially gives iip heat and when it reaches the last one of the series it is brought to t;5 the pressure of the atmosphere or very close to it, without boiling. In the remainder of the circuit, as the thermal cycle proceeds, between the las-t heat exchanger and the boiler, the hydrostatic press,,ire, as well as the pressure due to the use of the circulating pump, the highest To tempera,tures of the cycle are reached with a consequent saving in heat. E@@tented May 14, 1957 The invention wiH better be understood by the foflowing description of some preferred forms of circuit, reference being had to accompanying drawings, in which: Fig. I is a schematic representation of said type of circuit, serving four heat ut ising evices; Fig. 2 represents a circuit similar to that of Fig. 1, but according to a different embodiment of -thd invention. Rej'.erring now to the drawings, and particularly to Fig. 1: Water heated in the heater I is fed up through riser 3 to a manifold 4 for supplying the hot water under pressure to the inlet pipes 5 and 6 of the -two heat exchangers (or radiators) 7 located at the same level, for instance, the first floor of a building. Above each heat exchanger 7 is located a second heat exchanger 7 at a level corresponding for instance to the second floor of the building. The upper and lower heat exchangers of each ver@tical pair are serially connected. In other words, the outlet of the lower heat exchanger is connected to the inlet of its corresponding upper heat exchanger. The outlets S' and 6' from the upper heat exchangers are connected tbrough a manifold 8 to a common discharge or stand pipe 9 which discharges a-t its upper end into an expans;on vessel 10. The expansion vessel is connected by a conduit 11 to the intake of pump 2 for recirculating the water. It -,vill be read,'Iy understood that the water at the discharge side of ptimp 2 and in the heater 1 will be a-t the highest pressure and that the pressure of the water will decrease from a maximum at the discharge side of the pump 2 to a minii-num in the expansion vessel. Since the heater I is at the region of maximum pressure, the tem,)erature of -the water at this high pressure region can be raised above 100' C. without the water boiling. As the water heated above 100' C. passes upwardly throu.-h the lowest convector or heat exchanger 7, its temperature is reduced and also, due to the elevation, the presslre is less. By the time the water has passed through the vertical s@-ries of heat exchangers or convectors 7, its temperature is reduced below 100' C. so that it will not boil even at atmospheric pressure. Other advantages are obtainable with the circuit layout according to the invention, such as the following: (1) The air blowing-off from the heating elements is in an eas y and natural manner effected, owing to -the water ascensional motion, obtainable when it traverses the said elements. Therefore, the small blow-off valves, attached to tle normal heating elements or the air tubings between the top of the vertical pipe lines and the level of the expansion vessels, are eliminated and, consequently, tl-ic possibility of circulation defects due to air bubbles are eliminated. (2) Any danger due to an excessively forced combustion for ola@-its of the "@thermoconvector" or "aerothermal" with air fluid control type is eliminated, as all the consequences would be redticed to a free overflowing from the expansion vessel, even if the heating elements are not feeding the heat (i. e. when -the air flux is reduced). (3) It is possible to connect in the same circuit several utilisers at same level, even if obstacles are interposed, by having the water pipe pass below the obstacle while the air is conducted to air blowing-off pipes. (4) The two T-shaped connecting pipes normally used for each heating element are eliminated, when "thermoconvectors" of the throttle valve type, which are able to be traversed by the whole water of the verticaltubing, even in case of reduced load, are used. A modified form of system is shown in Figure 2 of the drawing in wliieh two auxiliary heat exchangers 12
[2]zkrq ,placed. i series in the return line 11 between the expansion vessel 10 and the intake of the pump 2 to utilise the heat in the water flowiilg in the return lin,-. Although two embodiments of the ge,.icric circuit, according to the present invention have been disclo@,,-d in the foregoing specification, it is understood that other modifications may be us,ed without departing from the true spirit and meaning of the invention itself. What I
