Patent Publication Number: US-10767854-B2

Title: Flameless steam boiler

Description:
BACKGROUND OF THE INVENTION 
     Embodiments relate generally to steam boilers. 
     A steam boiler is a form of low water-content boiler. A conventional steam boiler includes a water tank for storing water, a water supply line supplying water to the water tank, a heater heating the stored water, a steam line supplying generated steam to an outside, and a thermal fuse preventing overheating of the heater. 
     In such a conventional steam boiler, the water in the boiler is usually directly heated by the flame generated by the combustion by the burner. In this way, the flue gas generated during the combustion may be quickly taken away as the exhaust gas. This can consume much heat. Since the flame combustion state is not controllable, combustion may not be complete in certain pockets of areas in the combustion zone. The incomplete combustion can cause harmful gases. In addition, heat generated by the combustion in the conventional steam boiler can have limited contact with the stored water. This can cause heat loss and inefficient energy use. 
     BRIEF SUMMARY OF THE INVENTION 
     In general, embodiments provide an improved steam boiler. The steam boiler comprises a housing, which includes an up chamber and a lower chamber. The upper chamber and lower chamber are arranged at two opposite ends of the housing and are substantially parallel to each other. The housing of the steam boiler further includes a group of tubes arranged between the upper chamber and lower chamber. The tubes can be filled with liquids, such as water. The housing of the steam boiler still includes a gas structure arranged on a side of the tube group. The gas structure includes a burner and a gas inlet connected to the burner. The burner is arranged facing the group of tubes. Combustion can be provided through the burner to generate heat so that heat exchange with the liquid in the tubes can be achieved. 
     In such a configuration of a steam boiler in accordance with the disclosure, the flame or the high-temperature flue gas generated during the combustion can be diffused efficiently towards the tubes of in the group. The air flow within the housing of the steam boiler can help the high-temperature flue gas come into full contact with the surface of the tubes to complete the heat exchange. After such heat exchange, flue gas becomes low-temperature and can flow out of the housing. In this configuration, there is no furnace inside the steam boiler, and the flue gas can flow in a single turn. This also help reduce fire hazard caused by furnace explosion often seen in the conventional boilers. 
     In some embodiments, the tubes in the steam boiler in accordance with the disclosure may be arranged between the lower and upper chambers to form a cylindrical shape. In some embodiments, the tubes may form one or more concentric rings at a sectional face of the tubes, for example at the end of the upper chamber where the tubes are connected to the upper chamber. In some embodiments, the tubes may be arranged uniformly such that each tube has the same sized spaces to its neighboring tubes. In some embodiments, the tubes may be arranged un-uniformly such that each tube may not have the same sized space to it neighboring tubes. In some embodiments, the tubes may form one or more tube groups within the housing of the steam boiler in accordance with the disclosure. Each group of the tubes may form a cylindrical shape or any other shape. 
     In some embodiments, the lower chamber comprises one or more liquid inlets to allow liquids to flow into tubes. In some embodiments, the upper chamber may comprise one or more steam outlets to allow steams generated from the heat exchange between the flue gas and the surfaces of the tubes to be further used. In some embodiments, the gas structure is configured such that curve combustion zone is formed around the burner to generate heat. In some embodiments, the upper chamber and/or the lower chambers have a dish-like shape. In those embodiments, the dish-like shape has a flat side and a bulged side; and the tubes are connected to the flat sides of the upper and lower chambers. 
     This summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to be used in isolation to determine the scope of the claimed subject matter. The subject matter should be understood by reference to appropriate portions of the entire specification of this patent, any or all drawings, and each claim. 
     The foregoing, together with other features and embodiments, will become more apparent upon referring to the following specification, claims, and accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a diagram showing a front view of an exemplary a steam boiler in accordance with the disclosure. 
         FIG. 2  is a diagram showing a side view of the steam boiler shown in  FIG. 1 . 
         FIG. 3  is a diagram showing an exploded view of the steam boiler shown in  FIG. 1 . 
         FIG. 4A  shows one exemplary arrangement of tubes in an steam boiler in accordance with the disclosure. 
         FIG. 4B  shows another exemplary arrangement of tubes in an steam boiler in accordance with the disclosure. 
         FIG. 5A  shows another exemplary arrangement of tubes in an steam boiler in accordance with the disclosure. 
         FIG. 5B  shows still another exemplary arrangement of tubes in an steam boiler in accordance with the disclosure. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     With reference now to the drawings, and in particular to figures herein, an improved steam boiler system embodying the principles and concepts of the present invention and generally designated by the reference numeral  100  will be described. 
     As best illustrated in the figures herein, the steam boiler in accordance with the disclosure generally comprises a housing  200 .  FIG. 1  is a diagram showing a front view of an exemplary a steam boiler  100  in accordance with the disclosure.  FIG. 2  is a diagram showing a side view of the steam boiler shown in  FIG. 1 . As shown  FIG. 1  and  FIG. 2 , the housing  200  can include an upper chamber  6  and a lower chamber  5 . As also shown in both figures, the upper chamber  5  and lower chamber  6  can be arranged at two opposite ends of the housing  200  and can be arranged substantially parallel to each other. However, this is not intended to be limiting. It is contemplated that in some embodiments, the upper chamber  6  and the lower chamber  5  may not be parallel to each other. 
     In some embodiments, as shown in  FIG. 1  and  FIG. 2 , at least one of the lower chamber  5  or the upper chamber  6  can have a dish-like shape. In the embodiment shown in FIG.  1  and  FIG. 2 , both the lower chamber  5  and the upper chamber  6  have the dish-like shape such that there is a flat side and a bulged side. As shown, the lower chamber  5  has a flat side  52  and a bulged side  53 ; and the upper chamber has a flat side  63  and a bulged side  64 . In this example, the flat sides  52  and  63  face each other, and are substantially parallel to each other. The dish-like shaped upper chamber and/or lower chamber in the steam boiler  100  can increase structural strength of the steam boiler  100  and can simplify manufacturing of the steam boiler  100  compared with traditional steam boiler. 
     In some embodiments, as shown in  FIG. 1  and  FIG. 2 , the lower chamber  5  can have one or more liquid inlets  51  for allowing liquids, such as water, into tubes  3 . In some embodiments, as shown in  FIG. 1  and  FIG. 2 , the upper chamber  6  can have one or more steam outlets  61  for allowing steam, generated from heat exchange within the steam boilers, to escape from the housing  200  and to be further used. However, it should be understood that the liquid inlets  51  and steam outlets  61  are not intended to limit steam boiler in accordance with the disclosure. It is contemplated that in some other embodiments, a steam boiler in accordance with the disclosure may not have the liquid inlets  51  and/or steam outlets  61  as shown in  FIG. 1 . As still shown in  FIG. 1  and  FIG. 2 , the upper chamber  6  can have a fixing component  62 , which can be used to stabilize and fix the housing  200  of the steam boiler  100 . 
     As still shown in  FIG. 1  and  FIG. 2 , the housing  200  of the steam boiler  100  includes a group of tubes  3  that are arranged between the upper chamber  5  and lower chamber  6 . As mentioned above, the tubes  3  can be filled with liquids, such as water, from the inlets  51 . As shown, the tubes  3 , in this example, form a cylindrical shape between the upper chamber  6  and lower chamber  5 . 
     Also show in  FIG. 1  and  FIG. 2  is that the steam boiler  100  can include a gas structure  1  arranged on a side of the cylindrical shaped tubes  3 .  FIG. 3  is a diagram showing an exploded view of the steam boiler shown in  FIG. 1 . As shown in  FIG. 3 , in some embodiments, the gas structure  1  can include a burner  2  and a gas inlet connected to the burner. The burner  2  can be arranged facing the tubes  3 . Combustion can be provided through the burner  2  to generate heat so that heat exchange with the liquid in the tubes  3  can be achieved. In operation, premixed gas can be introduced into the gas structure  1  from the gas inlet and then burns on the surface of the burner  2  to generate high-temperature flue gas. The generated high-temperature flue gas is then dispersed among the tubes  3  to heat the tubes  3 . Through heat exchange, the heat is absorbed by liquids, such as water, in tubes  3 . As a result of such heat exchange, the heated water flows upward in the tubes  3  to enter the upper chamber  6  and generate steam in the upper chamber  6  for further use. 
     In such a configuration shown in  FIG. 3 , flame is only generated on the surface of the burner  2 , and thus the flame is not in direct contact with the tubes  3 . In this way, the combustion of the flame is controlled and the combustion is more thorough. U.S. patent application Ser. No. 15/671,124, filed Aug. 7, 2017, entitled “IMPROVED COMBUSTION CHAMBER” describes a grate structure that can be incorporated into various embodiments to facilitate the “flameless” heat exchange described herein and is incorporated herein by reference. As shown, the combustion zone  300  generated by the burner where the combustion takes place has a curve shape, which can lead to more complete combustion and thereby reduce pockets of areas where combustion is not full often seen in the traditional steam boiler. This can help reduce NOx generation during combustion and increase combustion efficiency. Such a “flameless” configuration can also improve the service life of the steam boiler  100  since there is no direct burning of the surfaces of the tubes  3 . 
     After being generated by the combustion by the burner, the high-temperature flue gas is dispersed to make contact with the tubes  3 . In this configuration, the contact area with the tubes  3  is large and thus increases heat exchange efficiency compared with traditional steam boiler. Such heat exchange efficiency increase can be attributed to the densely arranged tube  3  having spaces with respect to each other so that the high-temperature flue gas can flow through the tubes  3  and make contact with the surfaces of the tubes  3  fully. After the heat exchange with the tubes  3 , the flue gas becomes low temperature and flows out of the flue gas outlet  4  as shown. In this configuration, the boiler is a non-hearth design and the flue gas is a single return flow, which reduces the potential safety hazard of the hearth deflagration. 
     In various implementations, for increasing contact area with the high-temperature flue gas and/or heat exchange efficiency, the tubes  3  may be arranged to form one or more concentric rings at a sectional face of the tubes  3 .  FIG. 4A  shows one exemplary arrangement of tubes  3  in concentric rings. As show, the tubes  3  shown in  FIGS. 1-3  can be arranged spaced from each other to form concentric rings at one or both end of the tubes (for example at the end where the tubes  3  are connected with the upper chamber  6  and/or lower chamber  5 ) in some embodiments. In those embodiments, the spaces between each tube  3  may or may not be the same. That is, the tubes  3  may be arranged uniformly to have the same or substantially the same space size to each other and to form concentric rings. However, it should be understood that this is not necessarily the only case. In some other examples, the tubes  3  may be arranged non-uniformly such that the individual tubes  3  can have variable space sizes with each other to form the concentric rings  402 . 
       FIG. 4B  shows another exemplary arrangement of tubes  3  in an steam boiler in accordance with the disclosure. In this example, the tubes  3  can be arranged into tube groups  404 . Each tube group  404  may have an arrangement of tubes  3  in the group more or less the same as or similar to that shown in  FIG. 4A . The tubes  3  in the tube groups  404  may or may not have the same spacing arrangement. For example, one or more groups of tubes  404  may be arranged uniformly in terms of spacing and some other group(s) of tubes  404  may be arranged non-uniformly. As shown, the burner  2  can be arranged at one side of the tube groups  404  and the gas outlets can be arranged at the other side of the tube groups  404 . 
       FIG. 5A  illustrates another exemplary arrangement of the tubes  3  in a steam boiler in accordance with the disclosure. In this example, as shown, the tubes  3  can be arranged as triangles  502  having a same center  504 .  FIG. 5B  shows another exemplary arrangement of tubes  3  can have multiple tube groups  506 , with each having an arrangement more or less the same as or similar to that shown in  FIG. 5A . 
     The specification and drawings are, accordingly, to be regarded in an illustrative rather than a restrictive sense. It will, however, be evident that additions, subtractions, deletions, and other modifications and changes may be made thereunto without departing from the broader spirit and scope. Illustrative methods and systems for providing features of the present disclosure are described above. Some or all of these systems and methods may, but need not, be implemented at least partially by architectures such as those shown in  FIGS. 1-12  above. 
     Although embodiments have been described in language specific to structural features and/or methodological acts, it is to be understood that the disclosure is not necessarily limited to the specific features or acts described. Rather, the specific features and acts are disclosed as illustrative forms of implementing the embodiments. Conditional language, such as, among others, “can,” “could,” “might,” or “may,” unless specifically stated otherwise, or otherwise understood within the context as used, is generally intended to convey that certain embodiments could include, while other embodiments do not include, certain features, elements, and/or steps. Thus, such conditional language is not generally intended to imply that features, elements, and/or steps are in any way required for one or more embodiments or that one or more embodiments necessarily include logic for deciding, with or without user input or prompting, whether these features, elements, and/or steps are included or are to be performed in any particular embodiment.