Description:HEAT EXCHANGER ASSEMBLY WITH IMPROVED HEADER DESIGN AND COIL TO HEADER CONNECTION

FIELD OF THE INVENTION

The present invention in general, relates to a heat exchanger assembly for a steam boiler which has a simple design with reduced number of coil bending and number of permanent joints to be done on site.

More particularly, the present invention relates to a heat exchanger assembly for a steam boiler which has an improved header design and coil to header connection.

TECHNICAL BACKGROUND OF THE INVENTION

It is known that a boiler, more popularly termed as steam boiler, comprises heating of fluid for steam generation and generated steam is transferred to various processes or heating applications. Steam boilers are more specifically applied in thermal power generations in such plants.

Heat exchanger assemblies are associated with steam boilers for generation of steam and transfer of heat to different components of a boiler assembly which need such heat, for example say superheaters, evaporator and also other process equipment as known in this art.

Usually heat exchanger assemblies have, header, water outlet, water inlet, flue gas inlets and outlets. Saturated water enters the assembly through the water inlet while flue gas through the flue gas inlet. The flue gas heats the coils in the assembly which in turn heats the water converting it to steam. Coils associated with tubes are connected to header/header outlet of the heat exchanger assembly for conveying steam/hot water whereby heat is transferred to components in the steam boiler needing such heat, say for instance superheaters.

Now, for connection between coils associated with tubes and the header of the heat exchanger assembly it is known that there should be several field joints for connection between every two row of coils and the header. Due to higher starts, number of stub bending is high resulting into extra tube length. This also causes difficulties in accessing all tubes for welding in the field. Further, number of weld joints for connection between header and coils being more, this needs more erection time.

Another significant problem associated with coil to header connection known as explained in the preceding paragraph, is that too many number of loose components have to be brought to the site and welding these on site is also very time consuming.

To solve the above technical problems, the present invention provides a heat exchanger assembly with a unique header design which is connected to the coils in association with the tubes by means of a single connection, for every two rows of coils. This design also includes an integral unit having a plurality of coils in association with tubes which is brought to the field and fitted to the header as a single unit. The connection is done by means of a connecting element, for every two rows of coils in association with tubes.

Hence, the present invention in a nutshell drastically reduces the number of connections to be made at site between the header and every two rows of coils associated with tubes. This ensures reducing the bend and lengths of the tubes and facilitates accessibility from all directions to the zone where connection has to be established at site.

Due to the number of connections with header to be done at site being drastically reduced, total erection time is also reduced to a substantial extent.
OBJECTIVES OF THE INVENTION

It is the prime objective of the present invention to provide a heat exchanger assembly for a steam boiler having a uniquely designed header and header to evaporator coil connection whereby requirement for the number of connections to be done between header and evaporator coil is substantially reduced thereby reducing the erection time.

It is yet another objective of the present invention to provide a heat exchanger assembly for a steam boiler which reduces the number of stub bending and consequently length of tubing.

It is a further objective of the present invention to provide a heat exchanger assembly for a steam boiler having a uniquely designed header and header to evaporator coil connection whereby easy access to the zone where connections have to be done at site is possible.

It is another objective of the present invention to provide a superheater assembly for a steam boiler which has a uniquely designed header and header to coil connection whereby requirement for the number of connections to be done between header and coils is substantially reduced thereby reducing the erection time.

How the foregoing objectives are achieved should be clear from the contents of the specification hereinafter.

All through the specification including the claims, the words “Evaporator/Evaporator header/header”, “boiler”, “evaporator coil/tube”, “connections”, “weld joints”, “superheaters”, “process equipment” are to be interpreted in the broadest sense of the respective terms and includes all similar items in the field known by other terms, as may be clear to persons skilled in the art. Restriction/limitation, if any, referred to in the specification, is solely by way of example and understanding the present invention.
SUMMARY OF THE INVENTION

Accordingly, the present invention provides a heat exchanger assembly for a steam boiler comprising at least a header with an outlet, having connected thereto several rows of coils with tubes associated therewith. The assembly also has a water inlet header and flue gas inlet and outlet for movement of water and flue gas respectively in and out of the assembly. When the flue gas is passed over the coils water inside the assembly is heated for facilitating formation of steam. The steam is fed to the header by virtue of such connectivity and from the header to different components at different locations in the boiler arrangement. According to the invention, every two rows of coils in the assembly associated with tubes are securely attached to one connecting element, said connecting element having a single connection with said header for supply of steam vapour.

Preferably, the connecting element is a small header to which every two rows of evaporator coils with associated tubes are securely connected to.

More preferably, there are a plurality of rows of coils with associated tubes and small headers, such that every two rows of coils with associated tubes are connected securely to the small header and such plurality of coils(1) with associated tubes so connected with small headers constitute an integrally fabricated unit brough on site.

Even more preferably, each such small header with coils and tubes so connected are welded to the header by means of a single and permanent welding at site.

Most preferably, the steam vapour is fed to a superheater for conversion of wet steam to dry steam for accumulating more thermal energy for application in a thermal plant.

The heat exchanger assembly can be for a water tube boiler or for a fire tube boiler.

The present invention also provides a superheater assembly for a steam boiler for generation of thermal energy comprising at least a header with an outlet, having connected thereto several rows of coils with tubes associated therewith. The assembly also has a water inlet header and flue gas inlet and outlet for movement of water and flue gas respectively in and out of the assembly. When the flue gas is passed over the coils water inside the assembly is heated for facilitating formation of steam. The steam is fed to the header by virtue of such connectivity and from the header to different components at different locations in the boiler arrangement. According to the invention, every two rows of coils in the assembly associated with tubes are securely attached to one connecting element, said connecting element having a single connection with said header for supply of steam vapour.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
Having described the main features of the invention above, a more detailed and non-limiting description of some exemplary embodiments will be given in the following with reference to the drawings.

Figure 1 is a side view of conventional header design of heat exchanger assembly of a steam boiler, comprising the header and the evaporator coils.

Figure 2 is a perspective view of the header design shown in figure 1.

Figure 3 is an enlarged front view of a conventional header design.

Figure 4 is a side perspective view of the view shown in figure 3.

Figure 5 is a view as seen from top of the header and evaporator coil connection accoring to the conventional design.

Figure 6 is an enlarged view of the conventional connection between the header and evaporator coil in association with tubes.

Figure 7 is a side view of the header and evaporator coil connection of heat exchanger assembly according to the present invention.

Figure 8 is the perspective view of the view shown in figure 7.

Figure 9 is a front perspective view of the header design of the heat exchanger assembly according to the present invention.

Figure 10 is a rear perspective view of the header design of the heat exchanger assembly according to the present invention.

Figure 11 is a rear view of of the header design of the heat exchanger assembly according to the present invention.

Figure 12 is enlarged view of the connections between the evaporator coils and tubes with the header according to the present invention.

DETAILED DESCRIPTION OF THE INVENTION

The following describes a preferred embodiment of the present invention which is for the sake of understanding the invention and non-limiting.

It should be understood that the figures show an evaporator header. evaporator coils in association with furnace tubes, small headers, weld joints. It should be understood that this is a preferred embodiment only and the invention is not restricted to this embodiment. It merely explains the working of the invention and its novelty and inventive step. Further, in practice there can be a plurality of such units and the present invention embodies such units including variations in the number of components shown and orientation thereof.

Furthermore, steam boiler is not shown in the figures, since it is known, and the present invention is applicable on all types of boilers and heating applications facilitated by such boilers including superheaters and other process equipment.

As stated hereinbefore, the invention is not restricted to the embodiment illustrated in the figures and the description thereof, all of which are for understanding the invention, precisely its uniqueness and inventive step.

Only weld joints are shown in the figures as permanent joints. It should be understood that other permanent joints are also embraced by the invention. This is also true for the description of the figures.

Furthermore, it should be understood that the present invention is applicable to both Fire-tube boiler and also to water tube boiler.

In all the figures, like reference numerals represent like features.

As stated hereinbefore, while discussing technical background of the invention, for connection between coils associated with tubes and the header of the heat exchanger assembly it is known that there should be several field joints for connection between every two row of coils associated with tubes and the header.

Due to higher starts, number of stub bending is high resulting into extra tube length. This also causes difficulties in accessing all tubes for welding in the field. Further, number of weld joints for connection between header and coils being more, this needs more erection time.

Another significant problem associated with coil to header connection known as explained in the preceding paragraph, is that too many number of loose components have to be brought to the site and welding these on site is also very time consuming.

Now to understand the invention, first the conventional design has to be understood to grasp the technical problems in such header design of heat exchanger assembly of a steam boiler.

Figure 1 is a side view of a conventional evaporator which acts as a heat exchanger assembly in a steam boiler. It comprises an evaporator header (2) to which is connected the evaporator coils (1), figure 2 being its perspective view.

Referring to figure 3 and figure 6 in particular, it can be seen that to establish connection with the evaporator header (2) and the evaporator coils (1) in association with the tubes (4), several welding joints have been implemented as shown in detail in figure 6. For a row of evaporator coils (1) in association with tubes (4) there has to be ten number of welds per coil. Five of such weld joints are outside the bend. All these are brought to the site as loose components and these ten welding joints have to be done on the site for every row of coils (1) and tubes (4).

Thus, for every two rows of coils there should be twenty weld joints all to be done on site. From figures 4 and 5, it should be clear that there has to be a plurality of such connections with the evaporator header (2). Hence due to too many number of loose components to be welded on site, erection time is naturally very high.

Further, from figures 4, 5 and 6 in particular it would be clear that number of stub bending is high resulting in requirement for increased length of tubes. From figures 4 and 5 it should be also clear that accessibility to the zone of on site welding is a big problem due to the increased length of the tubes.

Referring to figure 7 it is a side view of the header design according to the present invention, figure 8 being a perspective view thereof. These figures show two rows of evaporator coils (1) which are welded to a small header (5), say 5 inches in diameter, which is connected to the evaporator header (2). Figure 8 makes this arrangement even more clear.

To understand the header design and the connections according to the present invention in more detail, reference should be made particularly to figures 9, 10 and 12.

Referring to figures 9 and 10, the evaporator header design according to the present invention would be more clear. The evaporator has a evaporator header (2). Now for every two row (6) of evaporator coil (1) in association with tubes (4) there is a small header (5). Every two rows (6) of evaporator coils are permanently attached (7) to a small header (5) and every small header (5) is connected (8) on site to the header (2) by say welding. So as compared to figures 4, 5 and 6 where for every two rows of evaporator coil (1) twenty welded joints had to be established on site, figures 9 and 10 indicate, that according to the invention, for every two row of coil (1) in association with tubes (4) only one welding joint(8) has to be established on site, that being between each small header (5) and the evaporator header (2).

The above connections would be clear from the elaboration provided in figure 12. It shows two rows of evaporator coils (1) in connection with tubes (4) being permanently connected to a small header (5) and the small header (5) is permanently connected (8) to the evaporator header (2).

From figures 9, 10 and 11 it would be clear that in practice there would be a plurality of small headers (5) each connected (8) on site with the evaporator header (2).

Now, the invention ensures that several components are brought to the site as an integral unit for connection with the evaporator header (2). According to the invention, small headers (5) having two rows of evaporator coils (2) associated with tubes (4) being connected to each small header (5) constitutes an integrally fabricated unit which is brough to the site. Thus, the welding joint (8) to be done on site, is only between the small headers (5) and the evaporator header (2). This saves a lot of time and the erection time is drastically reduced.

Apart from the above, it should be also clear that the number bends in the tubes, are reduced and hence is reduced the length of the tubes. Figures 9, 10, 11 and 12 also make it clear that, the zone for on site connection is easily accessible by virtue of the header design and the header to coil connection according to the present invention.

Thus, the crux of the present invention constitutes a heat exchanger assembly for a steam boiler comprising at least a header with an outlet, having connected thereto several rows of coils with tubes associated therewith. The assembly also has a water inlet header and flue gas inlet and outlet for movement of water and flue gas respectively in and out of the assembly. When the flue gas is passed over the coils water inside the assembly is heated for facilitating formation of steam. The steam is fed to the header by virtue of such connectivity and from the header to different components at different locations in the boiler arrangement. According to the invention, every two rows of coils in the assembly associated with tubes are securely attached to one connecting element, said connecting element having a single connection with said header for supply of steam vapour.

It is also within the scope of the present invention to provide a superheater assembly for a steam boiler for generation of thermal energy comprising at least a header with an outlet, having connected thereto several rows of coils with tubes associated therewith. The assembly also has a water inlet header and flue gas inlet and outlet for movement of water and flue gas respectively in and out of the assembly. When the flue gas is passed over the coils water inside the assembly is heated for facilitating formation of steam. The steam is fed to the header by virtue of such connectivity and from the header to different components at different locations in the boiler arrangement. According to the invention, every two rows of coils in the assembly associated with tubes are securely attached to one connecting element, said connecting element being in a single connection with said header for supply of steam vapour.

It should be clear from the description hereinbefore and the various figures that all the objetives of the present invention have been met. This would be even more clear from the appended claims.

The present invention has been described with reference to a preferred embodiment and some drawings for the sake of understanding only and it should be clear to persons skilled in the art that the present invention includes all legitimate modifications within the ambit of what has been described hereinbefore and claimed in the appended claims. , Claims:We claim:

1. A heat exchanger assembly for a steam boiler comprising at least a header (2) with an outlet, having connected (8) thereto several rows of coils (1) with tubes (4) associated therewith, said assembly also having a water inlet header and flue gas inlet and outlet for movement of water and flue gas respectively in and out of the assembly, such that as flue gas is passed over the coils (1) water inside the assembly is heated for facilitating formation of steam, said steam being fed to the header (2) by virtue of such connectivity and from the header (2) to different components at different locations in the boiler arrangement, characterized in that, every two rows (6) of coils (1) in the assembly associated with tubes (4) are securely attached to one connecting element (5), said connecting element (5) having a single connection (8) with said header (2) for supply of steam vapour.

2. The heat exchanger assembly as claimed in claim 1 wherein the connecting element is a small header (5) to which every two rows of evaporator coils (1) with associated tubes (4) are securely connected (7) to.

3. The heat exchanger assembly as claimed in claim 2 wherein there are a plurality of rows of coils (6) with associated tubes (4) and small headers(5), such that every two rows of coils (1) with associated tubes (4) are connected(7) securely to the small header (5) and such plurality of coils(1) with associated tubes (4) so connected (7) with small headers (5) constitute an integral unit brough on site.

4. The heat exchanger assembly as claimed in claim 3 wherein each such small header (5) with coils(1) and tubes (4) so connected (7) are welded to the outlet header (2) by means of a single and permanent welding (8) at site.

5. The heat exhanger assembly as claimed in any preceding claim wherein the steam vapour is fed to a superheater for conversion of wet steam to dry steam for accumulating more thermal energy for application in a thermal plant.

6. The heat exchanger assembly as claimed in any preceding claim wherein it is for a water tube boiler.

7. The heat exchanger assembly as claimed in any preceding claim wherein it is for a fire tube boiler.

8. A superheater assembly for a steam boiler for generation of thermal energy comprising at least a header (2) with outlet, having connected (8) thereto several rows of coils (1) with tubes (4) associated therewith, said assembly also having a water inlet header and flue gas inlet and outlet for movement of water and flue gas respectively in and out of the assembly, such that as flue gas is passed over the coils (1) water inside the assembly is heated by the flue gas for facilitating formation of steam, said steam being fed to the header (2) by virtue of such connectivity (8) and from the header (2) to different components at different locations in the boiler arrangement, characterized in that, every two rows (6) of coils (1) in the assembly associated with tubes (4) are securely attached to one connecting element (5), said connecting element (5) having a single connection (8) with said header (2) for supply of steam vapour.

Dated this 10th day of June, 2022

(SOUMEN MUKHERJEE)
IN/PA - 214