EP0890803A1 - Direct contact water heater with double chamber - Google Patents

Abstract

The water heater (10) has a seating (1) with a first water atomiser (12) in the seating to spray water onto a first heat exchanger array (13) held in the seating by a support (15). A heating gas duct (16) is in communication with an upper part of the a seating. A burner (17) is connected to an upper part of the seating to heat the water in a first reservoir in the seating. A second heat exchange array (21) is spaced from the first by a second support (22). A second sprayer (24) is above the second array. A second water reservoir (25) in the seating is below the first array. A passage (27) allows hot gases to pass from the second array to a position above the reservoir.

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 re-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.

We know direct contact water heaters that use two trim sections to heat water using two different heat sources, in particular the burner associated with the water heater, mounted at the base of the housing, as well as an external source of hot gases recovered from external devices. One such burner arrangement is, for example, described in US Patent 5,293,861. However, we have realizes that the efficiency of this type of direct contact water heater is decreasing drastically once the temperature of the intake water, that we usually releases through a spray nozzle at the top of the housing, exceeds 60 ° C. This therefore limits the use of water heaters to direct contact intended to give a source of very hot water so effective.

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 direct contact water heater with double tank sections hot water, the water in it being at different temperatures, characterized in that each of the sections is placed side by side to obtain a compact water heater housing.

Another aspect of the present invention is to provide a direct contact heater with double tank sections hot water stacked vertically on top of each other and ensuring efficient cooling with combustion gases which rise through the sections before exiting at the top of the housing.

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

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

Another aspect of the present invention is to provide a direct contact water heater with double tank sections hot water producing two hot water sources 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 comprising a housing comprising a first water spray nozzle disposed in the housing so as to spray the water to be heated towards descending on a first lining of heat exchange elements retained in a housing region by a support means. A exhaust pipe communicates with an upper part of the housing. A burner is connected to the lower part of the housing and is arranged to heat the water in a first water tank placed inside the housing. A second lining of heat exchange elements is kept apart above the first water tank by some other means of support. A second water spray nozzle is provided in the housing above the second packing for spraying water down on the second packing. An intermediate hot water tank is provided in the housing in a space located under the first lining. A way passage is provided for the passage of hot gases through the second packing so as to direct them towards a space situated above the intermediate tank. A pump means is associated respectively with the first and second water tanks so as to circulate the hot water from these to respective external exchange devices heat, connected respectively to a closed circuit, and using the burner unique.

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. The 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 as it rises 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 a 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).

According to the spirit of the present invention, it is intended to cover all obvious modifications of the preferred embodiment described above, to the provided that such modifications are provided for by the scope of appended claims.

Claims (15)

Direct contact water heater (10) comprising a housing (11) comprising a first nozzle (12) for spraying water disposed in said housing (11) for spraying water to be heated in the downward direction on a first lining (13) of heat exchange elements retained in a region of said housing (11) by a support means (15), a pipe (16) of exhaust gas in communication with an upper part of said housing (11), a burner (17) connected to a lower part of said housing and arranged to heat water in a first water tank (19) present inside said housing (11), a second lining (21) heat exchange elements kept spaced above said first water tank (19) by an additional support means (22), a second water spray nozzle (24) in said housing (11) above said second packing (21) for spraying water towards down on said second lining (21), a hot water tank intermediate (25) provided in said housing (11) in a region below said first lining (13), a passage means (27) allowing the passage of hot gases from said second lining (21) to a region located above said intermediate reservoir (25), and means for pumping (32, 32 ') associated respectively with one of said first (19) and second (25) water tanks to circulate hot water from these latter to respective external heat exchanger devices (31, 37), connected respectively in a closed circuit and using said burner (17). The water heater according to claim 1, wherein said means pump (32, 32 ') is a water pump connected between its own tank water (19, 25) and one end (30, 36) of a heat exchange circuit (31, 37), another end (34, 34 ') of said heat exchange circuit being connected to its own first (12) or second (24) water spray nozzle so that the water from said reservoirs (19, 25) is pumped through said heat exchange circuits (31, 37) where its temperature drops and is then sprayed onto its own lining (21,13) where it is warmed as it flows downward by gravity toward its own tank (19, 25). The water heater according to claim 2, wherein said water said first water tank (19) is at a temperature higher than said water from said second tank (25), said hot gases passing through said passage means (27) providing a source of hot gases for heating said heat exchange elements in said first lining (13) and the water flowing through it, said source of hot gases being cooled by said first lining (13) and the first spray of water before the latter leaves via said gas pipe (16) exhaust. Water heater according to claim 3, in which there are also provided an inlet (46) for hot recovery gases in a wall of said housing (11) in communication with a region (47) between said second water tank (25) and said first lining (13), allowing the entry of a secondary heat current in said housing recovered from one or several external heat devices (45). Water heater according to claim 3, in which there are also provided an inlet (46 ') of hot recovery gases in a wall of said housing in communication with a region (47 ') under the second lining (21) allowing the entry of a stream of hot secondary gases into said chamber recovered from one or more external devices (45). The water heater according to claim 1, wherein said housing (11) is elongated, vertical and tubular, said first nozzle of spraying water (12) being placed in the vicinity of an upper end said housing (11), said exhaust gas line (16) communicating with said upper end located above the first water spray nozzle (12), said first water tank (19) being formed in a lower part of said housing (11), the second lining (21) being spaced apart over a portion upper of said housing (11). The water heater according to claim 6, wherein said burner (17) is fixed to said housing (11) above said first water tank (19) and produces a flame (17 ') in a chamber (20) of the burner (17) constituted between said first water tank (19) and said second packing (21). The water heater according to claim 6, wherein said means passage (27) is a communicating passage extending through said second water tank (25) for the passage of hot gases rising from said second lining (21) and produced by said burner (17). The water heater according to claim 6, wherein said source hot gas exiting through said exhaust gas line (16) is a temperature below about 38 ° C, said external device (31) heat exchange associated with said first heating water tank (19) water by heat exchange with hot water from said first tank (19) from a temperature of around 71 ° C to a temperature of about 85 ° C, said external device (37) for exchanging heat with said second water tank (25) heating the water by exchange of heat with hot water from said second tank (25) from from a temperature of around 10 ° C and up to a temperature of around 60 ° C, said first water nozzle (12) ensuring water spraying at a temperature around 15.5 ° C. The water heater according to claim 1, wherein said housing (111) is built in two parts (A and B), the first (A) and the second (B) part being arranged side by side, said first nozzle (112) of spraying water being fixed in the vicinity of an upper part of said second part (B) and the second water tank (125) formed at the base of the second part (B), said first lining (113) being located in said second part (B) between said first spray nozzle (112) and said second tank (125), said second water spray nozzle (124) being fixed in the vicinity of an upper part of said first part (A) and said first water tank (119) formed at the base of the first part (A) under the second lining (121). The water heater according to claim 10, wherein said burner (117) is fixed to said first part (A) in the vicinity of said first water tank (119), a burner housing (120) in said first water tank (119) at least partially immersed therein, said tank burner (117) producing a flame (117 ') in said housing (120) at burner, said burner housing (120) having an exhaust port (54) extending above a high level of water present in said first tank (119) for removing hot gases from said housing (120) with burner. A heater according to claim 1, wherein said burner (117) is fixed to said housing (111) in the vicinity of said first tank of water (119), a burner housing (120) in said first water tank (119) at least partially immersed therein, said burner (117) producing a flame (117 ') in said burner housing (120), said burner housing (120) having an exhaust port (54) is extending above a high water level present in said first tank (119) for removing hot gases from said housing (120) at burner. The water heater according to claim 12, wherein said port exhaust (54) is constituted by one end of said housing (120) to burner opposite said burner (117) and comprises a vertical pipe (57) with lateral opening opposite an open region (58) between said first water tank (119) and said housing (120), and a structure gas cooling associated with said vertical pipe (57) and lateral opening. The water heater according to claim 13 wherein said gas cooling structure consists of a wall (59) upper of said pipe (57) and deflection plates (61, 62, 64) positioned to direct the hot gases upward toward said second lining (121) and to receive the water droplets (63) which circulate in order cooling said pipe and said deflection plates (61, 62, 64). The water heater according to claim 14, wherein said port exhaust (54) is disposed in the vicinity of an upper wall (59) of said vertical pipe (57), an arcuate deflection plate (62) disposed in front of said exhaust port (54) is provided for deflecting said gases hot discharged upwards in dispersed form.

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