EP0890803B1 - Direct contact water heater with double chamber - Google Patents

Description

The present invention relates to a direct contact water heater and more particularly a double section water heater comprising two hot springs; a first source of water at high temperature and a second source of hot water at a lower temperature. We heat the water present in the tank with a single or multiple burner or a single source of heat (e.g. flue gases) and it is recirculates in a closed loop with or without a device for exchanging external heat associated with the latter. This gives an increase efficiency, which is a function of the temperature of the water recirculated to injection devices which again inject the cooled hot water into the two sections of the water heater to heat and cool the hot gases ascending produced by the burner and / or entering the unit.

• un logement,
• un premier circuit fermé de refroidissement comprenant un premier ajutage de pulvérisation d'eau, ledit ajutage étant disposé dans ledit logement pour pulvériser de l'eau à chauffer en direction descendante sur un premier garnissage d'éléments d'échange de chaleur retenu dans une région dudit logement par un moyen de support,
• une conduite de gaz d'échappement en communication avec une partie supérieure dudit logement,
• un premier réservoir d'eau présent à l'intérieur dudit logement,
• un brûleur relié à une partie inférieure dudit logement et agencé pour chauffer de l'eau dans le premier réservoir d'eau,
• un second garnissage d'éléments d'échange de chaleur maintenu espacé au-dessus dudit premier réservoir d'eau par un moyen additionnel de support.

We know direct contact water heaters comprising:

• housing,
• a first closed cooling circuit comprising a first nozzle for spraying water, said nozzle being disposed in said housing for spraying water to be heated in a downward direction on a first lining of heat exchange elements retained in a region said housing by a support means,
• an exhaust gas line in communication with an upper part of said housing,
• a first water tank present inside said housing,
• a burner connected to a lower part of said housing and arranged to heat water in the first water tank,
• a second lining of heat exchange elements kept spaced above said first water tank by additional support means.

US-A-5,293,861 describes such a burner arrangement, further comprising a second heat source, different from the burner associated with the water heater and mounted at the base of the housing, and constituted by a external source of hot gases recovered from external devices. However, we realized that the efficiency of the contact water heater direct of this type dropped drastically once the temperature of intake water, which is usually released through a nozzle spraying at the top of the housing, exceeds 60 ° C. This therefore limits the use of direct contact water heaters intended to provide a source very hot water effectively.

One aspect of the invention is to provide a contact water heater direct with double sections of hot water tank, water in said tanks being heated by a single burner or burners multiple and / or external heat sources (including hot gases from other devices).

Another aspect of the present invention is to provide a water heater direct contact with double sections of water tank hot, the water in it being at different temperatures, characterized by what each of the sections is placed side by side to obtain accommodation compact water heater.

Another aspect of the present invention is to provide a water heater direct contact with double sections of hot water tank stacked vertically on top of each other for cooling efficient at flue gases rising through the sections before exit at the top of the accommodation.

Another aspect of the present invention is to provide a water heater direct contact with double sections of hot water tank and using a submerged burner housing, which is used as a source of unique heat to heat the water that infiltrates through the linings associated with each section of the water heater.

Another aspect of the present invention is to provide a water heater in direct contact with double sections of hot water tank, comprising a second source of hot gases from an external system, connected to the first or second section of the water heater.

Another aspect of the present invention is to provide a water heater direct contact with double sections of water tank hot water producing two sources of hot water at temperatures different, characterized in that the efficiency of the water heater increases clearly depending on the temperature of the intake water supplied to sections connected in a closed loop or an open loop provided with external heat exchange devices.

According to the aspects mentioned above, in its broad sense, the present invention provides a direct contact water heater having the characteristics according to claim 1.

la figure 1 est un schéma simplifié illustrant un chauffe-eau à contact direct avec des sections doubles de chauffage d'eau et des réservoirs d'eau doubles chacun comportant des circuits en boucle fermée de recirculation associés respectivement avec un échangeur de chaleur, chaque section de chauffe-eau étant placée l'une sur l'autre dans un logement vertical allongé de forme cylindrique ;

les figures 2A et 2B sont des schémas illustrant une source externe de chaleur reliée aux première et seconde sections du chauffe-eau à double section ; la figure 3 est une autre vue schématique montrant les gaz chauds provenant d'une source externe reliée à la première section du chauffe-eau à double section ;

la figure 4 est un schéma illustrant une autre version de la chambre du chauffe-eau dans laquelle les sections sont situées côte à côte pour obtenir un chauffe-eau à hauteur réduite ;

la figure 5 est un schéma illustrant une chambre de combustion immergée, associée avec le réservoir d'eau de la première section du chauffe-eau à double section ;

la figure 6 est une vue simplifiée, comme la figure 5, illustrant une extrémité de la chambre de combustion ; et

la figure 7 est un graphique illustrant le rendement du chauffe-eau à double section de la présente invention en comparaison avec un chauffe-eau à contact direct avec réservoir d'eau chaude unique.

A preferred embodiment of the present invention will now be described with reference to the accompanying drawings in which:

FIG. 1 is a simplified diagram illustrating a water heater in direct contact with double water heating sections and double water tanks each comprising closed loop recirculation circuits associated respectively with a heat exchanger, each section a water heater being placed one on top of the other in an elongated vertical housing of cylindrical shape;

Figures 2A and 2B are diagrams illustrating an external heat source connected to the first and second sections of the double section water heater; Figure 3 is another schematic view showing the hot gases from an external source connected to the first section of the double section water heater;

Figure 4 is a diagram illustrating another version of the water heater chamber in which the sections are located side by side to obtain a reduced height water heater;

FIG. 5 is a diagram illustrating a submerged combustion chamber, associated with the water tank of the first section of the double section water heater;

Figure 6 is a simplified view, like Figure 5, illustrating one end of the combustion chamber; and

FIG. 7 is a graph illustrating the efficiency of the double section water heater of the present invention in comparison with a direct contact water heater with a single hot water tank.

Referring to the drawings, and more particularly to FIG. 1, we generally see at 10 the double section direct contact water heater of the present invention. The water heater 10 includes a housing 11 comprising a first water spray nozzle 12 placed above a first lining 13 of heat exchange elements, not illustrated but obvious to those skilled in the art, maintained in an upper section or second B, identified by the reference number 14, of the housing Le lining 13 is retained in this section at a location predetermined by a support means 15, in particular an appropriate grid fixed all around of the inner surface of the circular wall 11 'of the housing.

An exhaust gas line 16 is located at the end of the upper part B of the housing to allow hot gases to escape cooled produced by a burner 17 located at the lower part A illustrated by the reference number 18, and constituting the high temperature portion of the water heater 10. As illustrated in the drawings, the burner 17 is connected to the wall 11 'of the housing 11 and is arranged to heat the water in a first water tank 19 of the lower part A of the housing 11. The burner 17 produces a flame 17 'in a region 20 of the lower part 18, above of the first tank 19. The burner 17, as illustrated, is a burner with natural gas capable of heating the water seeping into the lower part of the first tank 19, at temperatures sufficient for use in heating systems of large buildings, especially hotels, hospitals, etc. A second lining 21 of heat exchange elements is placed above the first water tank 19 and is further maintained in this place by a support means 22. The lower part 18, or at least the part containing the burner 17, can be constructed with a double wall such as illustrated in 23 to constitute a water cooling jacket around the burner compartment 10. A water spray nozzle 24 is also fixed above the second lining 21 to spray the water towards the low on the second lining 21 so as to heat the water by contact with the heat exchange elements and with the ascending hot gases produced by the flame 17 '.

A second water tank 25 is associated with the upper part B and consists of an intermediate wall 26 fixed so circumferential on the internal surface of the wall 11 '. It has a central pipe 27 and a cap 28 which is arranged spaced above of line 27 so as to allow hot gases to rise from the part A which rise through the second water tank 25 of part B to heat the water which circulates through the lining 13 and which is sprayed by the spray nozzle 12. The cap 28 prevents water flowing by gravity through the upper packing 13, to enter the part hot lower part of the burner. The gases which rise from the hot part A, illustrated by the arrows 29, are in the form of hot vapor which condenses by rising through the lining 13 and through the cooler water (less hot) sprayed from the upper nozzle 12. In addition, this hot steam condenses and flows from below to the second tank 25. Consequently, the water present in the lower tank 19 is at a temperature much higher than that of the water in the upper tank 25 because the single source of heat is arranged in the lower part A of the housing and cools down as it rises through the lower lining 21 and the upper lining 13, same as through the water sprayed through the spray nozzles. Typically, the water sprayed in the hot part particularly by the spray nozzle 24 may be at a temperature of around 60 ° C, while the water entering the upper part through the nozzle 12 can be at a temperature of around 6 ° C. The gases that exit through the line 16 are cooled to a temperature below about 38 ° C (37.7 ° C in particular), thus ensuring very efficient operation.

As described above, the water present in the hot part 18 and in the first tank 19 can be used for applications industrial and, as illustrated, this hot water recirculates in a circuit closed 30 through a heat exchange device 31 by means of a pump 32 connected to the closed circuit 30. At an outlet 34 of the exchange device heat 31, the water is cooled by heat exchange with the fluid which enters the heat exchange device 31 through an inlet 33. This cooled hot water comes out of outlet 34 directly connected to the nozzle of water spray 24 where it is sprayed and heated to a temperature upper as it flows through the packing, the hot gases ascending and the flame 17 '. As shown, the water entering the heat exchange device 31 can be at a temperature of about 74 ° C and heats up in the heat exchange device 31 thanks to the water from the hot water tank 19 for leaving said heat exchange device, at an outlet 35, at a temperature of about 85 ° C.

In the colder upper part 14 of the housing 11, the water from the tank 25 also recirculates by means of a pump 32 'in a closed circuit 36 through a heat exchange device 37, and returns to the nozzle of spraying 12 through line 34 '. This water is at a temperature lower and can be used as a heat source to heat water domesticated. Typically, domestic water can be kept in a tank (not shown). Hot water from the tank enters the exchanger heat 37 at an inlet 38 at a temperature of about 10 ° C and will come out at an outlet 39 at a temperature of about 60 ° C. The hot water of the circuit closed 36 which leaves the heat exchange device 37 is sent to the spray nozzle 12 and is typically found at a temperature about 15.5 ° C. This cooled water is sufficient to cool the gases hot which rise through the lining 13, this allowing the water heater 10 double section to obtain an efficiency of about 95% using a single burner or multiple burners 17.

The fresh water supplied by the city illustrated in 25 'can also be supplied to the spray nozzle 12 by closing a 25 "valve and opening a valve 26 '. Hot water can then be sent to the pipe outlet 36 'by opening a 36 "valve, and be used for applications industrial or commercial.

As illustrated in Figures 2a, 2b and 3, the contact water heater 10 direct and to two sections of the present invention can also be connected to a secondary heat source 45. In the present case of FIGS. 2a and 2b, it this is a kettle located in a remote location, so as to recover hot gases from the kettle which are normally at temperatures about 315.5 ° C, and reinsert them into double water heaters section.

As illustrated in FIG. 2a, an outlet 46 for recovering gas hot is provided in the wall 11 'of the housing 11 and communicates with a space 47 located above the water tank 25 and under the first lining 13. Typically, the hot gases rising through this space 47 and produced by burner 17 are at a temperature of about 77 ° C and saturated in water vapor. Therefore, the secondary source of hot gases will cause so that the temperature of the water flowing through the packing 13 will rise and cause the temperature of the water in tank 25 to rise upper part B.

As illustrated in Figure 2b, an outlet 46 'for recovering gases hot is provided in the wall 11 'of the housing 11 and communicates with a space 47 'located above the water tank 19 and under the lining 21.

Figure 3 is another version of the external system recovery of hot gases according to which the gas inlet 46 is illustrated here as being connected to the wall 11 'of the housing 11 but communicates with a space 20 above the first water tank 19 of the lower part A.

Referring now to Figure 4, we illustrate another construction of the housing 111 of the water heater 10 in direct contact with the present invention. As illustrated, the two parts 114 and 118 are arranged side by side so that the height of the housing 111 is reduced by considerably. This may be desirable depending on the location in which accommodation must be provided. As illustrated, the lower part of the first part 114 constitutes the water tank 125 placed under a lining 113. The spray nozzle 112 is placed above the packing 113 and under an exhaust pipe 116. A passage communicating 48 is provided between region 49 located above reservoir 125 and the end upper 50 of the second part 118 in the vicinity of the nozzle of water spray 124. The water tank 119 in part 118 is located at the base of part 118 and under lining 121. In order to save space available, a burner housing 120 is introduced into the tank 119 and we immerse it at least partially in the latter. As illustrated in Figures 5 and 6, the burner 117 produces a flame 117 'inside the housing 120 for heating the water surrounding housing 120.

As illustrated, the burner housing 120 is provided with an outlet exhaust 54 located above the high water level present at the interior of the tank 119, allowing the discharge of hot gases to from the burner chamber 120, as illustrated by the arrows 55.

As best seen in Figures 5 and 6, the output exhaust 54 is formed at one end of a vertical section 57 of duct of the housing 120, the exhaust orifice 54 being in the form a side opening located opposite the open region 58 above the water present in the tank 119. Because the gases discharged through the orifice exhaust 54 are very hot, it is necessary to cool the section vertical pipe 57 and deflecting the rising gases towards the droplets of water which escape by gravity from the lining 121. Consequently, one thus obtains a gas cooling structure.

The gas cooling structure is provided by the wall upper 59 of the vertical pipe defining an open basin 60 at its upper part and extending in 60 'around the walls to accumulate the water droplets 63 which flow downwards from the lining 121 to cool the top wall 59. In addition, deflection plates 61 and 62 are placed so as to direct the escaping hot gases, as this is represented by the arrow 55, upwards towards the second lining, to cool these hot gases by heat exchange with the water droplets 63 which come from the lining 121.

As illustrated, the deflection plate 62 is arched and more narrower than the exhaust port 54 to deflect the gases upward and next to. Another deflection plate 64 is provided on each side of the base of the plate 62 to ensure another deflection of the hot gases towards the up and to the sides. These deflection plates 62 and 64 are fixed to the housing 120 of the burner, as illustrated in FIG. 6. The deflection plate 62 is fixed along the upper edge of the outlet orifice 54 to send the hot gases against the deflection plate 62 in order to disperse the gases, as shown by arrow 55.

We built the double direct contact water heater 10 of the present invention and evaluated its thermal efficiency as is represented in the following table which gives measurements obtained from parts A and B of the water heater. Typically, part A is the part producing high temperature water and using a gas burner to give the energy necessary for the production of water at high temperature. The part B is used to recover the energy present in the gases which rise from part A and this produces hot water which is sufficient for constitute a source of hot water capable of heating the tap water supplied by the municipality in proportion to the energy available in the gases warm, and keep them inside the tank 25 of part B. The energy available in part B is a function of the gas temperature of conduct.

Table 1 which follows gives the results obtained from a test carried out on a prototype water heater constructed according to the present invention. Thermal Efficiency - Double direct contact water heater Part A Water temperature at the nozzle (° C) 63.3 70.0 78.8 79.8 Burner gas temperature (° C) 67.2 72.8 80.9 81.6 Spilled water (nozzle) (gpm) 260 260 253 256 Power (kW) 850 850 850 850 Efficiency (%) 75 63 47 43 Part B Water temperature at the nozzle (° C) 1.2 1.2 1.1 1.3 Burner gas temperature (° C) 11.2 14.8 24 35.2 Spilled water (nozzle) 25.5 29.5 32.5 29.5 Efficiency (%) 99 96 100 93 Total efficiency (%) 99 99 99 96 Note: the air factor is 1.3.

Referring now to Figure 7, we give a comparison results obtained with the double section water heater in this invention compared to the theoretical curves obtained for a water heater with direct contact of the prior art having a single water tank. Figure 7 shows the efficiency curve 70 of the double section water heater of the present invention compared with that of a direct contact water heater with single hot water tank 71. On this curve we have also shown the efficiency curve 72 of the hot part A of the double burner and we can note that the effectiveness of this part A considered independently falls quickly once the temperature of the inlet water, i.e. the water to the spray nozzle 24, is above 60 ° C. However, the combination with part B allows the water heater to increase its efficiency above 90% with the parameters illustrated in table 1.

It will also be noted that the water heater 10, when it is in "summer", does not require high temperature water from the lower part A to heat buildings. As a result, the water in tank 19 can recirculate directly to the spray nozzle 24, through the circuit 30 'diversion, to produce saturated hot gases which will rise to through part B to give heat to the hot spring domesticated. The same effect could be achieved by simply closing the fluid circulation on the secondary side of the heat exchanger 31 (entry 33 and exit 35).

Claims (15)

1. Direct-contact water heater (10) comprising:

   a casing (11),

   a first closed cooling circuit (36) comprising a first water spraying nozzle (12), said nozzle (12) being arranged in said casing (11) so as to spray water that is to be heated in a direction falling onto a first lining (13) of heat exchange elements held in an area of said casing (11) by a support means (15),

   an exhaust gas pipe (16) which communicates with an upper portion of said casing (11),

   a first water tank (19) inside said casing (11),

   a burner (17) connected to a lower portion of said casing and arranged so as to heat water in the first water tank (19),

   a second lining (21) of heat exchange elements, positioned spaced above said first water tank (19) by an additional support means (22),

   a second closed cooling circuit (30) comprising a second water spraying nozzle (24), said nozzle (24) being arranged in said casing (11) above said second lining (21) so as to spray water in a direction falling onto said second lining (21),

   a second hot water tank (25) provided in said casing (11), in an area situated below said first lining (13),

   a means of passage (27) which allows the hot gases to pass from said second lining (21) to an area situated above said second tank (25),

   a first and a second pumping means (32', 32), associated respectively with the second (25) and the first (19) water tanks, for circulating the hot water from these water tanks respectively through the first cooling circuit (36) and second cooling circuit (30) to respectively a first (37) and a second (31) external heat exchange device, each cooling circuit (36, 30) and each external heat exchange device (37, 31) being independent of one another.
2. Water heater as claimed in claim 1, wherein said first and second pumping means (32, 32') are water pumps connected between their own water tank (19, 25) and one end of the first and second external heat exchange devices (31, 37) respectively, another end (34) of the external heat exchange devices (31, 37) being connected to their own first (12) or second (24) water spraying nozzle so as to pump the water from said tanks (19, 25) through said external heat exchange devices (31, 37), where the temperature drops and the water is then sprayed over their own lining (21, 13), where it is reheated whilst circulating downwards by gravity to their own tank (19, 25).
3. Water heater as claimed in claim 2, wherein the water in said first water tank (19) is at a higher temperature than the water in said second tank (25), the hot gases passing through said means of passage (27) providing a source of hot gases for heating said heat exchange elements in said first lining (13) and the water circulating through the latter, said source of hot gases being cooled by said first lining (13) and the first water spray before the latter exits via said exhaust gas pipe (16).
4. Water heater as claimed in claim 3, wherein there is also provided an inlet (46) for recovered hot gases (46) in a wall of said casing (11) communicating with an area (47) between said second water tank (25) and said first lining (13), making it possible for a secondary heat flow to enter said casing after the recovery thereof from one or more external heat sources (45).
5. Water heater as claimed in claim 3, wherein there is also provided an inlet (46') for recovered hot gases in a wall of said casing communicating with an area (47') below the second lining (21), making it possible for a stream of hot secondary gases to enter said chamber after recovery thereof from one or more external devices (45).
6. Water heater as claimed in claim 1, wherein said casing (11) is elongate, vertical and tubular, said first water spraying nozzle (12) being positioned in proximity to an upper end of said casing (11), said exhaust gas pipe (16) communicating with said upper end situated above the first water spraying nozzle (12), said first water tank (19) being constituted in a lower portion of said casing (11), the second lining (21) being supported at a distance above an upper portion of said casing (11).
7. Water heater as claimed in claim 6, wherein said burner (17) is fixed to said casing (11) above said first water tank (19) and produces a flame (17') in a chamber (20) of the burner (17) which is constituted between said first water tank (19) and said second lining (21).
8. Water heater as claimed in claim 6, wherein said means of passage (27) is a communicating passage which extends through said second water tank (25) for the passage of hot gases rising from said second lining (21) and produced by said burner (17).
9. Water heater as claimed in claim 6, wherein said source of hot gases leaving via said exhaust gas pipe (16) is at a temperature lower than approximately 38°C, said external heat exchange device (31) associated with said first water tank (19) heating the water by heat exchange with the hot water coming from said first tank (19), from a temperature of approximately 71°C to a temperature of approximately 85°C, said external heat exchange device (37) with said second water tank (25) heating the water by heat exchange with the hot water coming from said second tank (25), from a temperature of approximately 10°C and up to a temperature of approximately 60°C, said first water nozzle (12) providing water atomisation at a temperature of approximately 15.5°C.
10. Water heater as claimed in claim 1, wherein said casing (111) is constructed in two parts (A and B), the first part (A) and the second part (B) being arranged side by side, said first water spraying nozzle (112) being fixed in proximity to an upper portion of said second part (B) and the second water tank (125) constituted at the base of the second part (B), said first lining (113) being situated in said second part (B) between said first water spraying nozzle (112) and said second tank (125), said second water spraying nozzle (124) being fixed in proximity to an upper portion of said first part (A) and said first water tank (119) constituted at the base of the first part (A) below the second lining (121).
11. Water heater as claimed in claim 10, wherein said burner (117) is fixed to said first part (A) in proximity to said first water tank (119), a burner casing (120) in said first water tank (119) at least partially immersed in the latter, said burner (117) producing a flame (117') in said burner casing (120), said burner casing (120) having an exhaust port (54) which extends above a high water level present in said first tank (119) in order to discharge the hot gases from said burner casing (120).
12. Water heater as claimed in claim 1, wherein said burner (117) is fixed to said casing (111) in proximity to said first water tank (119), a burner casing (120) in said first water tank (119) at least partially immersed in the latter, said burner (117) producing a flame (117') in said burner casing (120), said burner casing (120) having an exhaust port (54) which extends above a high water level present in said first tank (119) in order to discharge the hot gases from said burner casing (120).
13. Water heater as claimed in claim 12, wherein said exhaust port (54) is constituted by one end of said burner casing (120) facing said burner (117) and has a vertical pipe (57) with side opening opposite an open area (58) between said first water tank (119) and said casing (120), and a gas cooling structure associated with said vertical pipe (57) and the side opening.
14. Water heater as claimed in claim 13, wherein said gas cooling structure is constituted by an upper wall (59) of said pipe (57) and diverter plates (61, 62, 64) positioned so as to direct the hot gases upwards in the direction of said second lining (121) and so as to receive the circulating water droplets (63) in order to cool said pipe and said diverter plates (61, 62, 64).
15. Water heater as claimed in claim 14, wherein said exhaust port (54) is arranged in proximity to an upper wall (59) of said vertical pipe (57), and an arc-shaped diverter plate (62) arranged in front of said exhaust port (54) is provided to divert said upwardly discharged hot gases in a dispersed form.

Images