Title of Invention

CERAMIC FUEL INLET ELBOW GATE.

Abstract

This invention relates to an integrated shut-off device in a fuel-firing system of a boiler, comprising an elbow-shaped gate body (1) with ceramic lining, the body (1) is so configured to allow an approachable space for maintenance having provision of a ceramically-lined rotatable disc (2). The body (1) is connected through a connecting means (13) to a plurality of pipes of the system via a coupling means. A drive shaft (5) of the system accommodating a drive plate (10) via atleast one spring dowel (11), the drive shaft (5) is rotated by an actuator (8) and transferring the rotating motion of the shaft (5) to the disc (2) via the disc plate (2). The device is opened when the rotating motion of the drive shaft (5) including a delivery pressure of the air-fuel flow of the system exceeds a pre-set limit thereby allowing the disc (2) to take a position to provide a free- flow of the supplied air-fuel flow.

Full Text

FIELD OF THE INVENTION The invention gerally relates to a shut off device in a fuel firing system of boiler. More particularly, the invention relates to an integrated shut off device for isolating the fuel supply system of a boiler. BACKGROUND OF THE INVENTION Fuel is fired to the combustion unit (Boiler furnace) using air as the transporting medium. In a fuel firing system, pulverized fuel from the pulverizers are carried to the burners by air through a plurality of parallel lines of pipes. The air, which carries the fuel to the burner is called primary air" and supplied to the furnace along with the fuel. A secondary air" is supplied to the boiler through a compartmentalized secondary air duct. The supplied air is distributed and regulated by a number of secondary air dampers actuated by equivalent number of air cylinders. The fuel compartments are sandwiched one over the other with the air compartments disposed in between. The burner tips are tilted upward and -downward by means of atleast one tilt link. Hence, a pulverized fuel firing system, in particular, a corner fuel firing system consists of damper drives, tilt drives and monitoring means, in addition to the burner components. Hence the fuel firing system need continuous monitoring. Based on the monitoring results, firing of fuel to the boiler is to be intermittently cut oft during the operations. Hence, a periodical shut off of the fuel firing system requires isolation of the burners from the fuel supply lines of the system. According to the existing art, slide valve devices are employed to act as the shut off device. This device occupies a space which is almost twice that of the pipe diameter and twice the height of the drive. Thus, the slide valve device takes away the major portion of the maintenance space provided for the burners including the approach area leading to difficulty in operational monitoring and approachability during maintenance of the system. The size of the valve device also interferes with the damper drive means of the burner assembly. US patent No. 5020776 dated 04.06.1991 tilted "split seat gate valve"by Owens, et al. discloses a gate valve assembly, which has two aligned and connected body housing members which each has a gate slot above a through-passage which is disposed above a seat portion of the gate slot. In this new art, the gate is an integral part of a fuel inlet elbow and the turning movement of the drive shaft helps in closing and opening of the gate valve assembly. US patent No. 6,260,490 dated 17.09.2001 titled "Burner isolation valve for pulverized fuel systems" by wark, et al. discloses an isolation gate which includes a valve plate assembly and a sealing mechanism for the valve plate assembly. In this new art, the shaft bearings are sealed externally along with succeeding groove rings, which ensures tight sealing. The actuating mechanism operates a shaft with a disc for closing and opening of the port. OBJECTS OF THE INVENTION Accordingly, it is an object of the present invention to propose an integrated-shut off device which does not require additional space. Another object of the present invention is to propose an integrated shut off device which provides sufficient and easy approachability for maintenance of the inner components of the burner. A still another object of the present invention is to propose an integrated shut off device which provides easy access to the burner area. A further object of the present invention is to propose an integrated shut off device which can withstand the abrasive flow of coal gas mixture. A still further object of the present invention is to propose an integrated shut off device which requires less assembly time. An yet further object the present invention is to propose an integrated shut off device which requires application of optimum drive force. An yet another object of the present invention is to propose an integrated shut off device which is simple, easy to operate and less costly. SUMMARY OF THE INVENTION Accordingly, there is provided an integrated shut off device which basically comprises an elbow gate for fuel inlet configured as an integrated structure of the burner bend. The gate body is an elbow body with ceramic lining having provision for maintenance including space for accommodating a disc. A drive shaft is actuated by a drive lever, which is connected to an actuator shaft by means of a plurality of connectors and securing means. The turning motion is transferred to the disc by a disc plate, which is locked to the drive shaft by means of atleast one spring dowel. The shaft is supported at both ends on atleast two shaft bearings. The shaft bearings are sealed externally. The disc is pressed on a valve seat against the fuel air mixture flow by the drive shaft. The drive force associated with the disc is sufficiently high to provide a tight sealing. The body and the disc facing the fuel air flow is completely insulated with ceramic materials. The shaft bearings are sealed externally along with each succeeding groove rings for tight sealing. The device is provided with a maintenance door, which provides access to the inner component. The disc is actuated by means of an actuator or by a hand lever. The shaft is turned by means of an actuator lever connected to the actuator. The actuators are actuated by means of a solenoid valve having speed regulator. The gate body constitutes an welded steel structurd and completely ceramic lined to withstand the abrasive action of fuel flow. The seat of the valve device is made of wear resistant high grade steel. In the closed position, the valve is pressed onto the valve seat against the coal air mixture flow by the drive shaft. The drive force associated with the disc load is sufficiently high to provide a tight seal. When the gate is opened, the turning motion of the drive shaft and the additional support of the delivery pressure causes the disc to open to 60 degree, thus providing a free flow. BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS Further objects, features and advantages will be apparent from the following detailed description when taken in conjunction with the accompanying drawings. Pig. 1 shows an elevation view (partially sectioned for details) of the integrated shut-off device accotipg to the invention. Fig. 2 shows a side view of the integrated shut off device of Fig.l. DETAIL DESCRIPTION OF A PREFERRED EMBODIMENT OF THE INVENTION Referring to the Figs 1 and 2, the gate body (1) is an elbow body with ceramic lining having provision for maintenance and a space for accommodating the disc (2). A drive shaft (5) is actuated by a drive lever (4), which is connected to an actuator shaft of an actuator (8) by means of a plurality of connectors and securing means (9). The generated turning moment is transferred to the disc (2) by a disc plate (10), which is locked to the drive shaft (5) by means of atleast one spring dowel (11). The shaft (5) is supported at both ends by atleast two shaft bearings (12). The shaft bearings (12) are sealed externally along with the succeeding groove rings for tight sealing. A connecting means (13) is incorporated in the elbow gate, so that it can be connected to the pipes by means of a pipe coupling. The actuator (8) is supported from the top by means of several supporting components (14). The pneumatic actuator (8) is actuated by a solenoid value (15), which is incorporated with a flow restricto to control the speed of the disc (2) for smooth closing and opening WE CLAIM 1. An Integrated shut-off device In a fuel-fiying system of a boiler, comprising - an elbow-shaped gate body(1) with ceramic lining, the body (1) having provsion for maintsnance door and a space for accommodating a ceramicalty-lined rotated disc (2), the body (1) being connected through a cormecting means (13) to a plurality of pipes of the system via a coupling means/ and a drive shaft (5) of the system characterized in that the drive shaft is Integrated with a drive plste (10) via atloest one spring dowel (11), the drive shaft (5) is rotated by an actuator (8) and tfansfeming the rotating motion of the shaft (5) to the disc (2) via the dise plate (10) to press a valve seat (3) against the fuel air mixture flow, the device being opened when the prossrng rorce of the disc from rotating motion of the drive shaft (5) with the delrvery presselof theair- fuelflow of the system exceed a pre-set Iimit there by allowing the disc (2) to take a position to provide a free- flow of the supplied air-fuel flow. 2. The device as claimed in claim 1, wherein the drive shaft (5) is actuated by a drive lever (4) which is connected to the actuator by a pluraltty of securing means (9). 3. Tnedevice as claimed,clim1,wherein arleast two bearing (12) which are sealingly placed on a pluraltty of succeeding groove rings on the system. 4. The device as claimed in any of the preceding claims wherein, the actuator (8) is operated by a solenoid valve (15) 5. The device as claimed in claim 1, wherein the actuator (8) is supported from top by a several supporting components (14). 6. An integrated shut-off device in a fuel-firing system of a boiler as substantially described herein and illustrated with reference to the accompanying drawings. This invention relates to an integrated shut-off device in a fuel-firing system of a boiler, comprising an elbow-shaped gate body (1) with ceramic lining, the body (1) is so configured to allow an approachable space for maintenance having provision of a ceramically-lined rotatable disc (2). The body (1) is connected through a connecting means (13) to a plurality of pipes of the system via a coupling means. A drive shaft (5) of the system accommodating a drive plate (10) via atleast one spring dowel (11), the drive shaft (5) is rotated by an actuator (8) and transferring the rotating motion of the shaft (5) to the disc (2) via the disc plate (2). The device is opened when the rotating motion of the drive shaft (5) including a delivery pressure of the air-fuel flow of the system exceeds a pre-set limit thereby allowing the disc (2) to take a position to provide a free- flow of the supplied air-fuel flow.

Documents:

00873-kol-2005-abstract.pdf

00873-kol-2005-claims.pdf

00873-kol-2005-correspondence.pdf

00873-kol-2005-description (complete).pdf

00873-kol-2005-description (provisional).pdf

00873-kol-2005-drawings.pdf

00873-kol-2005-form 1.pdf

00873-kol-2005-form 18.pdf

00873-kol-2005-form 2.pdf

00873-kol-2005-form 3.pdf

00873-kol-2005-form 5.pdf

00873-kol-2005-gpa.pdf

00873-kol-2005-letter patent.pdf

00873-kol-2005-reply f.e.r.pdf