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(11) | EP 0 524 128 A1 |
| (12) | EUROPEAN PATENT APPLICATION |
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| (54) | Steam generator, usable as a heater and a boiler |
| (57) Steam generator, usable as a heater and a boiler, composed of a boiler (10), a thermic
fluid (60) which has a boiling point between 5-50°C, an electrical heating source
(30), a diffuser of transformation heat of the thermic fluid, made up of a number
of tubes (20) bent in inverted "U" and some medium (40) propelling an air convection
current trough this number of tubes in its variant of realization to work as a boiler,
the number of tubes (20) in inverted "U" are enclosed into a tight deposit or frame
(70) through which a current of water is made circulate by conventional wais. |
[0001] This invention refers to a steam generator device, usable as an autonomous heater to warm rooms by forced convention or as a boiler for a heating system or hot water supply.
[0002] There exist numerous heating devices wich, in case of working by forced convention make use of either an electrical heating source (resistance) through which a current of air is made pass, or a dis- postion of tubes provided with (fan-coils) through which the water vapour generated in a separated and recatively distant boiler, circulates. Thus, a current of air is force through these tubes.
[0003] These well-known heaters using water vapor require complex and expensive installations, especilly because of the relatively high pressure they must work at and because of the necessity of recirculations circuits which enable the condensed water to return to the generating boiler.
[0004] Because of these reason, such heaters can hardly be autonomous, that is to say, they do not usually have the boiler and the heat diffuser to gether in the same unit, being the heat dragged along by convection current. They cannot work as proper boilers either, even throgh little modifications or additions were made to enable them to feed a conventional heating system or a hot water supply.
[0005] The steam generator of the invention has the advantage of being an autonomous heating unit, with a high thermic out-put, which can be transformed, by means of little modifications, into a feed boiler of a circuit of conventional heating radiators or a hot water supply.
[0006] To do so, the generator of the invention makes use of the well-known puysical principle of cession of transformation heat, for instance when a gas turns into a liquid. In the case of water, it is the transformation of steam into a liquid and it has a value of 540 cal/kg. valne which is given or given bach wuen the water vapour recovers its liquid state.
[0007] Therefore, water would be a thermic fluid usable in the steam generator of the invention. However, water has a boiling point of 100°C. in normal conditions of pressure, which implies a heating source that reaches at least such a temperature, which is relatively high for a heater of domestic use, for instance, and makes the building and functioning of the device more expensive.
[0008] The generator of the invention is based on the use of a thermic fluid which its liquid state at moderate temperatures, to which it will have a boiling point with- ing an interval of possible ambient temperatures (5-50°C), so that a cicle of transformation of estates with cession of vaporization heat of a fluid can be achieved with a heating source of modest possibilities.
[0009] An example of such a thermic fluid is the so called "freon-11" (CC13F) which presents a boiling point of 23,8°C. At 1 ATM, a freezing point of -111°c and vaporization heat of 43,5 cal/g. Beside, it has the advantage of not being inflammable, corrosive or toxic.
[0010] According to the invention, a steam generator usable as an autonomous heater has:
- A boiler.
- A thermic fluid which, in its liquid state, fills at least partially the boiler, and which has a boilin point between 5-50°C.
- An outer heating source for the boiler.
- A diffuser of transformation heat of the thermic fluid, composed of a number of tubes in inverted "U", whose ends are partially introduced into the upper part of the boiler.
- Some medium propelling an air convection current the number of tubes.
[0011] In a preferable way of realization, the heating source is an electrical resistance in contact with the outer wall of the boiler, whitch is usually cylindrical. Howenver, there will be no difficulties to install the heating source inside the boiler.
[0012] It will also be preferable for the tubes in inverted "U" forming the heat diffuser to be linked by a number of fan-coils.
[0013] In a variant of realization, the steam generator can work as a boilerfor other conventiona heater dev- iles or for hot water supplies. To do so, the number of tubes in inverted "U" are enclosed in a deposit of tight frame through which a current of water is made circulate by conventional way. In this way of realization, as well as being electrical the heating source can also be worked by gas, glp, fuel-oil, Etc.
[0014] The building and functioning of the steam generator of the invention will be easier to understand starting from the following description of schematic examples of practical realization,given with no limited char- racter at all and illustrated on the enclosed sheet in which:
Figure 1 shows schematic view of the front elevation with some parts pulled up, of a generator, allord- ing to the invention, in its application as heater.
Figure 2 shows the side elevation and vertical section of a view equivalent to the one mentionet above.
Figure 3 is a schematic view in perspective of a variant of realization of the generator of the invention.
Figure 4 is a schematic view which illustrates an example of realization of the generator of the invention functioning as a boiler
[0015] Reffering to the example of realization illustrated in figures 1 and 2 the machine of the invention consists of an autonomous heater of domestic use, for instance, composed of a cylindrical boiler (10) preferably made of copper where the ends of a number of tubes (20) bent in inverted "U" are inserted through its upper part preferably, the ends of the tubes (20) are kept inside the boiler (10) by soldered joints (11), while the fan-coils (21) go over the surface of the tubes (20) and join some groups of tubes to others . Such tubes and fan-coils (20,21), will be preferably made of aluminium.
[0016] Figure 3 shows a schematic variant of realization, in which the in inverted "U"(20) are arranged in pairs stamped on semi-ssets (22) made of steel, which are soldered by their edges, so that the surface of contact for the convection current is increased.
[0017] The heating source for the boiler (10) is an. Electrical resistance (30) of segments or cylindrical or partially cylindrical sections, those of the shielded kind available in market, in contact with the outer surface of the boiler (10). On the other hand, the elctrical resistance is convered by a carcass or insulating con- vering (31).
[0018] The electrical resistance may also be situated inside the boiler (10), and, in this case, it would remain submerged in the liquid (60).
[0020] The unit is arranged inside a holder or a box (50) provided with its corresponding grilles (51) for the forced convection current to get in and out.
[0021] The boiier (10) is partially filled with a thermic fluid (60), "freon-11" for instance, which when it is heated up by the resistance (30), begins to boil and comes up in the form of vapour through the tube (20), where it gets cold and return to liquid state to fall to the boiler (10) after its vaporization heat diminishes.
[0022] The cold of the atmosphere is sucked in by the fan (40) through the lower grille (51) and it is obliged to circulate through the tubes (20) and fan-coils (21), where it gets hot and comes out through the. hioher arille (51) to complete a convection circuit preferably, the air current is guide through the inner part of the box (50) by a baffle plate (52).
[0023] The control of the appliance is realized by pushing the buttons (70) which act on the feeding of the resistance (30), the fan speed (40), and they also respond to the regulation of the desired temperature by means of the thermostat (41) situated in the lower entrance (51) of the ambient air.
[0024] In an example of functioning, a 4 I. capacity boiler(10) may be filled in its three quarter partswith the liquid (60), preferably "freon-11" while the resistance (30) will supply a heating of 50-60°C. Which will be enough to cause the liquid to boil (60) by keeping a vaporization-condensation cicle at a pressure of 1-3 atm. In the boiler. The fan will have, for instance, a capacity of 200-250 m3/h. Thas is to say, the vallies of temperature and pressure are moderate enougu as to allowthe domestique ausage, of the steam generator of the invention as a heater, for instance.
[0025] In spite of the reduced values of the pressure in the boiler (10), this will be provided with its corresponding safety valve for overpressure and pressure regulator. Figure 4 shows the basic structure of a. generator, according to the invention, when it works as a boiler. According to its presentation , many of the characteristics describes before remain, such as the boiler (10), resistance (30), insulating loverin (31), tubes (20), fan-coils (21) and thermic liquid (60). The modifications consist in the fact that the unit of tubes (20) and fan-coils (21) is encolosed in a water tight insulated box or deposit (70), provided with pipe (71,72) for a liquid usually water to get in and out. This liquid is heated while circulating through the tubes and fan-coils (20,21). This heated liquid will be useful to be di- recty used or to warm up a series of conventional radiators. The deposit (70) will be connected to a conventional circuit of circulation or canalized distribution not represented.
1.- Steam generator, usable as an autonomous heater, characterized because it has:
- A boiler (10),
- A thermic fluid (60), +hat fills at least partially the boilet in its liquid state and that has a boiling point between 5-50°C.
- An outer heating source (30) for the boiler.
- A diffuser of the transformation heat of the thermic f!u!d, composed of a number of tubes (20) bent in inverted "U", whose ends are partially inserted in the upper part of the boiler (10).
- Mediums (40) impelling the convection air current through the tubes.
2.- Steam generator, according to vindication 1, characterized because the heating
source (30) is situated inside the boiler (10).
3.- Steam generator, according to the vindications above, characterized because the
heating source (30) is an electrical resistance.
4.- Steam generator, according to the vindications above, characterized because the
number of tubes (20) in inverted "U" are joined by fan-coils (21).
5.- A steam generator, usable as a boiler, characterized because it has:
- A boiler (10).
- A thermic fluid (60), which fills at least partially the boiler in its liquid state and whose boiling point is between 5-50°C.
- An outer heating source (30) for the boiler.
- A diffuser of transformation heat of the thermic fluid, composed of a number of tubes (20) bent in inverted "U", whose ends are partially inserted in the upper part of the boiler (10),
- Acarcass (70), which encloses tightly the diffuser (20), provided with entrance and exit for a circulating liquid which will be heated.
6.- Steam generator, according to vindication 5, characterized because the heating
source (30) is situated inside the boiler (10).
7.- Steam generator, according to vindication 5, characterized because the number
of tubes (20) in inverted "U" are joined by fan-coils (21).
8.- Steam generator, according to the vindications above, characterized because the
thermic fluid (60) put into the boiler (10) is "freon-11 ".