Title of Invention

"A HORIZONTAL COILS SUPPORT FOR HEAT RECOVERY SURFACES OF BOILERS."

Abstract

A horizontal coils support for heat recovery surfaces of boilers comprising of double passage bent tubes vertically or horizontally for flow of steam/water inside and flue gas outside for heating characterized in that the horizontal tubes (1) are supported by vertical hanger tubes (2) provided by a vertical plate (5) with notches (6) at regular interval to reduce thermal stress and attached to vertical hanger tube (2) by welding (7) and at the other end of the said vertical plate (5) is attached spacer clip (4) and U-Clips (3) by welding with the horizontal tube (1) clamped rigidly between the said spacer clip (4) and U-Clip (3) and thus forming the support.

Full Text

The invention relates to a horizontal coils support for heat recovery surfaces of boilers. Heat Recovery surfaces like economizers, superheaters and reheaters are used in utility boilers to increase the cycle efficiency of the Power of Plant. These are fabricated mainly out of bent tubes arranged vertically or horizontally. The flue gas flows outside the hollow cylindrical tubes and steam/water flows inside the tubes. The flue gas heats the steam/waterinside the tubes. These horizontal coils are supported by steam-cooled vertical hanger tubes. These supports are fabricated from Steel Plates and firmly welded to tubes of the horizontal coils to the vertical hanger tubes. There are disadvantages associated with the existing support arrangement. One of the main disadvantages associated are that while the tubes are steam cooled the supports do not have cooling arrangements. 2. Another disadvantage of the existing support is that due to high heat exposive it is fabricated from high alloy heat resistance steel which is expensive. Therefore, the main object of the present invention is to provide a simple, effective and economical support for the horizontal coil tubes to the vertical hanger tubes. An object of the present invention to propose a construction of the support system with a vertical Plate welded to horizontal at one end and the other end with spacer clip and U-Clip to the vertical tube. Another object of the Present invention is to propose a construction of a support system welded and attached to the tubes in a such manner so that the entire construction is adequatedly cooled along with the tubes. Yet another object of the present invention is to propose construction of the vertical plate from low alloy steel as the plate is cooled by the steam in the vertical tube. Thus, cost is reduced considerably. According to the present invention there is provided a horizontal coils support for heat recovery surfaces of boilers comprising of double passage bent tubes vertically or horizontally for flow of steam/water inside and flue gas outside for heating characterized in that the horizontal tubes are supported by vertical hanger tubes provided by a vertical plate with notches at regular interval to reduce thermal stress and attached to vertical hanger tube by welding and at the other end of the said vertical plate is attached spacer clip and U-Clips by welding with the horizontal tube clamped rigidly between the said spacer clip and U-Clip and thus forming the support. The nature of the invention, its objective and further advantages residing in the same will be apparent from the following description made with reference to non-limiting exemplary embodiments of the invention represented in the accompanying drawings. Fig. 1. A view in elevation of the support assembly Fig. 2. A side view of the support assembly. Fig. 3. A view in plan of the support assembly In accordance with the present invention, the horizontal tubes (1) are supported by steam-cooled vertical tubes at more than 2 locations. The load is transferred from the horizontal tube (1) to the vertical tube (2) and in turn transferred to the ceiling structure. The support is made up of U-clips (3), bent spacer clips (4) and notched vertical plates (5). The U-Clips (3) and bent spacer clips (4) are made-up of stainless steel, to withstand high flue gas temperature. The vertical plate is attached to the steam-cooled vertical hanger tube by welding. As the vertical plate (5) is cooled by the steam in the vertical tube, the same is at a relatively low temperature. Hence, low alloy steel is used for this. The vertical plate is notched (6) at regular intervals to reduce thermal stresses. The intervals of the notches are usually at same intervals of the spacer (4) and U-Clips (3) and the horizontal tube (1). The load is transferred from the horizontal tube to the vertical plate through the 'U'-Clips (3). The U-Clip (3), is attached to the vertical plate by welding. The thickness of the U-Clip and vertical plate are suitably selected to withstand the load transferred. The vertical hanger tube is designed is such a way that the stresses due to internal pressure and weight are within allowable limits. The construction is symmetrical, rugged and easy to fabricate. The combination of vertical plate (5) spacer clip (4) and the U-Clip is unique to form a support for the horizontal tube. Spacer chip (4) is U-Shaped and outside of the two I-arm is close fitted inside the U-Clip and the base of the U-Shape spacer clip (4) is circular shape close fitted to the horizontal tube (1). The U-Clip (3) is also adapted for a close fit with the horizontal tube (1). Thus the combination of two clips (3 & 4) rigidly holds the horizontal tube (1). Both the clips (3 & 4) are provided with notches at ends to fit into the vertical plate (5) and welded for rigidity. The invention described herein above is in relation to a non-limiting embodiment and as defined by accompanying claims. WE CLAIM: 1. A horizontal coils support for heat recovery surfaces of boilers comprising of double passage bent tubes vertically or horizontally for flow of steam/water inside and flue gas outside for heating characterized in that the horizontal tubes (1) are supported by vertical hanger tubes (2) provided by a vertical plate (5) with notches (6) at regular interval to reduce thermal stress and attached to vertical hanger tube (2) by welding (7) and at the other end of the said vertical plate (5) is attached spacer clip (4) and U-Clips (3) by welding with the horizontal tube (1) clamped rigidly between the said spacer clip (4) and U-Clip (3) and thus forming the support. 2. Horizontal coil support as claimed in claim 1, wherein the interval of notches (6) of the vertical plate (5) is at the same intervals of spaces (4) and the U-Chips (3) and the horizontal tube (1). 3. Horizontal coil support as claimed in claims 1 & 2 wherein the spacer clip (4) has outside dimension to close fit inside of the U-Clips (3). 4. Horizontal coil support as claimed in claim 1 to 3 wherein the spacer clip (4) and U-Clip (3) are bent to a circular shape to fit hold rigidly the horizontal tube. 5. Horizontal coil support as claimed in claims 1 to 4 wherein construction of the support with two clips (3 & 4) and vertical plate (5) are welded together to the horizontal tubes (1) and vertical tubes (2) to provide a rigid support. 6. Horizontal coil support as claimed in Claims 1 to 5 wherein the two clips (3 & 4) are made of stainless steel and the vertical plate (5) made from low alloy steel. 7. A horizontal coil support for heat recovery surfaces of boilers as herein above described and illustrated.

Documents:

535-del-1997-abstract.pdf

535-del-1997-claims.pdf

535-del-1997-correspondence-others.pdf

535-del-1997-correspondence-po.pdf

535-del-1997-description (complete).pdf

535-del-1997-drawings.pdf

535-del-1997-form-1.pdf

535-del-1997-form-19.pdf

535-del-1997-form-2.pdf

535-del-1997-form-3.pdf

535-del-1997-gpa.pdf

abstract.jpg