MAXseal

FIELD OF INVENTION

The present Invention relates to a new arrangement useful in any system for managing multiple axis expansion and ensuring seal to the pipes, and more particularly in drain pipes of boilers discharging solid particles like ash at high temperature and pressure.

BACKGROUND OF THE INVENTION:

Piping systems routinely expand and contract in response to changes in temperature, internal or external loadings and anchor movements. Especially pipelines experiencing expansion in multiple directions during the transfer of substances or solid particles at high temperature and pressure are handled using various existing systems like weld assembly, flange assembly, single mitre corner, camera corner, hinged metal, gimbals metal, pantographic metal, pressure balance metal and pen seal metal. Although they support to some extent, they are complex in manufacturing, material selection, increase the cost of production and in turn become a limitation to use.

These kinds of expansion occur even in boilers and sometimes cause damage to the pipelines. In thermal power generation units, the one main type of boilers used is fluidized bed boilers where solid fuel is utilized as the primary source. The used fuel expels with high temperature and it is disposed as ash. Disposal of the used fuel is a major problem in the existing scenario. Fluidized bed boiler has ash drain system in order to dispose the ash.

In some fluidized bed boiler, bottom ash drain pipes are used and they handle a large quantity of ash which contains heavier stones and foreign particles along with typical ash at high temperatures in the range of 900 - 1000 C and at pressures usually higher than atmospheric pressure. The ash drain pipes are generally attached to the combustor of a top supported boiler. During boiler operations, these pipes will experience expansions in axial and lateral directions, and sometimes angular and torsional movements. These types of multi-axis expansion growth lead to the leakage of ash if the drain pipe system is not properly designed.

A conventional fabric or metallic expansion joint might take care of these multi-directional expansion movements and at the same time provides sealing. Some conventional systems employed are rectangular or circular form of expansion joints and made of metal, rubber, steel, titanium or formable material to overcome leakages. But selection of a suitable material for the expansion joint for the said operating conditions is quite a challenge and provides the limitation to the existing system.

Alternately, there has been a simple telescopic arrangement (without a diskette) which overcome the expansion on boiler operation, but they do not assure sealing. Hence ash puffs out from the system during boiler operation and makes the environment unclean and unsafe. Also In some existing systems, springs can be added to the telescopic chutes to hold for sealing but they could be vulnerable in that dusty surrounding.

The system of the present invention overcomes the above disadvantages by managing multi-axis expansions and providing seal for the pipe especially for ash drain pipes in boilers and it allows a clean and safe environment.

The present invention is for use in any system having an application of draining high temperature solid particles, especially systems like a fluidized bed boiler with bottom ash drain system employed beneath the combustor.

SUMMARY OF THE INVENTION:

The present invention relates to a new system called MAXseal system useful in any system having an application of draining high temperature solid particles. This system is mainly applied to boilers such as fluidized bed boiler provided with bottom ash drain system beneath the combustor.

The purpose of this invention is to provide a seal for bottom ash drain pipe system and take care of the multiple axis expansion movements of the pipes during the discharge of solid particles like ash from boilers resulting in a simple and safe ash drain system.

The MAXseal system has a diskette with ceramic felts and a telescopic chute arrangement. The diskette has been held between the two welded attachments of the ash drain pipe. During ash drain, when the pipe expands in lateral direction, space clearance for expansion of the drain pipes is maintained by diskette with ceramic felts arrangements.

The ash drain pipe is inserted into another pipe to facilitate the telescopic movement. Upon boiler operation, this telescopic movement will take care of the downward expansion of the ash drain pipe.

The main features of the invention include (1) the use of ceramic felts with diskette arrangement (2) easy to install and remove with the help of both vertical and horizontal bolted connections (3) the use of ceramic felts avoid any direct metal to metal contact and the ceramic felts are easy to detach from diskette and replace if required (4) sealing of ceramic felt in the groove of the diskette (5) the use of diskette arrangement in a telescopic expansion provision system (6) the arrangement of the system is less complex and ensures safe and clean environment by providing required sealing from the finer, hot ash that puffs out of the draining system. The system avoids the expansion of joints and higher grade material.

The system also includes a provision of making the drain system completely water-cooled as a design improvement.

The further aspect of the invention is that the MAXseal system can be utilized in any system where multi-axis expansion of pipe is experienced.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 illustrates the front view of the MAXseal arrangement.

DETAILED DESCRIPTION OF THE INVENTION

The present invention is directed to a new arrangement termed MAXseal utilized in any system to overcome and manage the problems happening in the pipelines while discharging or transferring solid particles such as ash or molten slag or other refuse materials at high temperature and pressure. The pipelines used to expand in any direction during those circumstances and this system supports the pipes from being distorted or damaged. (

The present invention is directed more towards the use of the system for the efficient handling of bottom ash drain system employed beneath the combustor in boilers. I

The MAXseal system is developed considering the multiple axis expansion movements that the pipes experience during the ash drain process in the boiler operation.

Figure 1 illustrates the MAXseal arrangement showing diskette with ceramic felts and a telescopic chute arrangement.

The system has an inner ash flow pipe 1 at the top side of the arrangement and the ash flow pipe holds two welded attachments 2 of the ash drain pipe. The diskette 3 was held between two welded attachments 2 of the ash drain pipe. Diskette 3 is held between the two welded attachments 2 in such a way that these welded attachments could slide over the diskette 3 when the ash flow pipe expands in the lateral direction. The ceramic felts 5 are fixed in the respective grooves of the diskette 3. The free space available all around between the ash flow pipe 1 and the diskette 3 is filled with loose wool 6. This loose wool 6 avoids any metal to metal contact between the ash flow pipe 1 and the diskette 3, when the ash flow pipe expands laterally. The diskette 3 along with the welded attachments 2 provides the required sealing for the fine ash particles discharging under high pressure and high temperature from the ash flow pipe 1. The whole system with the diskette 3, welded attachments 2, ceramic felts 5 and the loose wool 6 are all inside a bolted chamber 4, which is removable both horizontally and vertically.

The whole arrangement can be engaged inside the bottom ash drain system employed beneath the combustor of any system especially a fluidized bed boiler.

During boiler operation, large amount of solid fuel is burnt to produce energy and the process will usually take place at high temperature and above atmospheric pressure. In a fluidized bed boiler, fluidized bed is conventionally located in the bottom of the boiler furnace and the heat generated by burning fuel is transferred to the water being heated by the boiler by different modes of heat transfer such as radiation, convection and conduction (not shown in figure). After combustion, the solid particles (ash) leave the furnace on their way to a discharge system through the ash flow pipe 1 of the bottom ash drain system.

The solid particles while discharging from the combustion chamber to the ash pipe flow 1 at high temperature and pressure cause multiple axis expansion such as vertical and lateral expansions of the bottom drain pipes. When the expansion of the pipe takes place in the lateral direction, sufficient provision for expansion is maintained by the diskette 3 for the pipe to move over it. As said, loose wool 6 ensures the space clearance, carefully designed and provided by holding the diskette 3 with the ceramic felts 5 within the welded attachments 2. The loose wool 6 is utilized when there is any expansion of the drain pipes in lateral direction.

Also, the clearance space is maintained by the diskette 3 during the expansion movement, apart from providing the necessary sealing for the high pressure, fine, hot ash from the pipes coming out under all circumstances when the boiler is in operation.

The advantage of this invention is that the ash flow pipe 1 gets in point of contact with the two welded attachments 2 at its opposite ends. Whereas in the existing system, expansion joints like single mitre corner, camera corner, pantographic metal get in contact with ash pipe throughout their total surface and therefore the total surface of the expansion joint experiences thermal conductivity along with the expansion of the pipe and reduces the life of the materials used in the expansion joints.

The invention further explains the insertion of ash drain pipe into another pipe to facilitate the telescopic movement. There is enough space provided between the drain pipes. Upon boiler operation, when the ash drain pipe expands downward, this telescopic movement will provide easy movement of the ash drain pipe within the system and the ash discharges from the system without any damage to the external pipe. The arrangement of the invention ensures a safe and simple ash drain system.

In the present invention, the diskette arrangement in a telescopic expansion provision system is a new, unique feature. These arrangements are kept inside a chamber 4 through bolted connections. Further, the advantage of the invention is the use of ceramic felts 5 with diskette arrangement. Ceramic felts 5 are provided to avoid any direct metal to metal contact. The ceramic felts 5 are fixed in the respective grooves of the diskette 3 in such a way that it is easy to detach and replace the felts if and when required. Ceramic felts £ sealed in the groove of the diskette are unique in this invention. One or two ceramic felts £ can be used in the diskette 3.

This MAXseal system involves a less complex design including selection of materials components and it is connected in a simple and safe way. Therefore, installation and removal of any components are very easy with the use of both vertical and horizontal bolted connections. The use of complex welding of dissimilar metals and any heat treatment procedures are not applicable for this system. The MAXseal system is easy to install and remove by way of the provision of bolted chambers both in horizontal and vertical directions The system avoids the expansion joints and higher grade material and so complexities are nil or avoided. The system also avoids the usage of refractory linings. The system takes care of the expansion and provides the required sealing during operation of the unit at various circumstances.

The drain system usually deals with solid particles at high temperature and pressure ant therefore the MAXseal system includes provision of making the drain arrangement completely water-cooled as a design improvement. The water cooling arrangement with separate inlet and outlet can be individually engaged around the inner ash flow pipe an( outer pipe to reduce the temperature of the solid particles flowing out.

The MAXseal system can be applied to any fluidized bed boilers such as Bubbling Fluid Bed (BFB) and Circulating Fluid Bed (CFB) boilers.

Moreover, this invention is not limited towards its use in fluidized bed boiler; it can also be used in any system or applications where the pipes undergo multi-axis expansion. For example, this system can be applied to power plants, cement plants, steel plants and so on.

WE CLAIM:

1. The new MAXseal system is developed for use in any system having an application of draining high temperature solid particles, the system comprising: (a) diskette with ceramic felts and (b) telescopic arrangement

2. The system according to claim 1, can be utilized to manage the multiple axis expansion movements experienced by the pipelines at high temperature and pressure in any systems

3. The system according to claim 1, can handle solid particles that can be typical ash or molten slag or other refuse materials to be discharged safely.

4. The system according to claim 2, can be utilized in any boiler type with bottom ash drain system employed beneath the combustor for the efficient removal of ash deposits.

5. The system according to claim 1, has the ceramic felts fixed in the groove of the diskette and these felts are easy to remove and replace on conditions.

6. The system of claim 5, diskette with ceramic felts provides space clearance filled with loose wool.

7. The loose wool as said in claim 5 takes care of the ash flow pipes when they get lateral expansion.

8. The system according to claim 1, wherein telescopic arrangement is established by the insertion of ash drain pipe into another pipe and they will take care of the downward expansion of the pipe during hot discharge of fine ash from the boiler.

9. The system according to claim 1, is less complex and can be applicable to any systems having an application of draining high temperature solid particles

10. The MAXseal system is developed for use in the boilers like fluidized bed boilers with bottom ash drain system for draining solid particles at high temperature and pressure, the system comprising: (a) diskette with ceramic felts and (b) telescopic arrangement

11. The system of claim 1, provides safe and clean environment by managing multi-axis expansions and providing seal for the ash drain pipe.

12. The system according to 9, has provision for making the drain system completely water- cooled.

13. The system according to claim 5, ceramic felt is sealed in the groove of the diskette.

14. The system according to claim 13, wherein one or two ceramic felts can be attached to the diskette.

15. The system according to claim 9, is easy to install and remove by way of the provision of bolted chambers both in horizontal and vertical directions.

16. The system according to claim 9, is simple without the usage of any refractory linings, higher material grade, complex welding etc.

17. This MAXseal system, according to claim 1, can be applied to any system that is installed vertically or horizontally or at an angle.