System and method for implementing intrinsic safety in rotating machine

Abstract

The embodiments herein disclose a system and method for providing an intrinsic safety to rotating machinery from the failure of internal high speed rotating structures. According to one embodiment herein, a system assembly comprises a unique design of the rotating structure to provide a sufficient safety margin and redundancy in configuration. The system assembly comprises a blower fan assembled inside a blower casing and rotated inside the casing. The fan is manufactured by a single forging process instead of an investment casting. The fan comprises several blades mounted to a hub in a shroud to draw a required quantity of fluid. The fan is mounted to a shaft through the hub. When the blower fan is rotated at a high speed exceeding the design parameters, a ‘rub and stop’ mechanism is initiated to halt the fan.

What is claimed is: 
     
         1 . An intrinsic safety system for a rotating machine comprising:
 a rotating structure and wherein the rotating structure a is a blower fan, and wherein the blower fan is rotated under the influence of pressure from an incoming fluid, an wherein the blower fan comprises a plurality of blades configured to assist the blower fan in drawing a required quantity of the fluid, a hub configured to mount the blower fan on a shaft and a shroud configured to enclose the blades of the blower fan;   a blower casing configured for holding the blower fan;   a rub and stop mechanism configured to halt the rotating blower fan, wherein the rub and stops mechanism is initiated when the blower fan is rotated at a high speed exceeding a plurality of design parameters, and wherein the rub and stop mechanism causes a rubbing of the blower fan against a surrounding static structure, and wherein the static structure surrounding the blower fan is the blower casing.   
     
     
         2 . The system according to  claim 1 , wherein the plurality of blades imposes a centrifugal load on the hub and the shroud when rotated at high speeds. 
     
     
         3 . The system according to  claim 1 , wherein the blower fan is mounted on the shaft through the hub, and wherein the blower fan and the shaft are assembled with a help of a plurality of pins, a bushing and a lock nut. 
     
     
         4 . The system according to  claim 1 , wherein the bushing and the plurality of pins are configured to position the shaft properly with respect the blower fan, and wherein the lock nut is adopted to tighten the blower fan to the shaft. 
     
     
         5 . The system according to  claim 1 , wherein the blower fan further comprises a loading section and a loaded section, wherein the loaded section is the hub and the shroud and wherein the loading section comprises the plurality of blades. 
     
     
         6 . The system according to  claim 1 , wherein the loading section of the blower fan is supported by at least two loaded sections, wherein the blower fan is designed to provide a dual redundant retention structure. 
     
     
         7 . The system according to  claim 1 , wherein the hub and the shroud act as the retention structures when a crack is present in the blower fan, and wherein the retention structures provide a desired strength to bear the imposed loads to reduce a failure. 
     
     
         8 . The system according to  claim 1 , wherein the plurality of blades is designed to drive a large volume of fluid through the blower fan, and wherein the fluid enters the blower fan through the plurality of blades and exits through an exit duct. 
     
     
         9 . The system according to  claim 1 , wherein the blower casing is configured to guide the fluid flow to a peripheral device attached to the rotating machine, through the exit duct. 
     
     
         10 . The system according to  claim 1 , wherein the blower fan is brought to halt due to a friction caused by rubbing of the blower fan with the surrounding static structure. 
     
     
         11 . A method for providing an intrinsic safety to a rotating machine, comprising steps of:
 expanding a blower fan in a radial direction, when a blower fan is rotated at a high speed exceeding a plurality of design parameters;   rubbing the blower fan against a surrounding static structure, due to the radial expansion of the blower fan; and   stopping a rotation of the blower fan due to a frictional contact between the blower fan and the surrounding static structure.   
     
     
         12 . The method according to  claim 11 , wherein the blower fan is radially expanded to cause a rubbing against the surrounding static structures to bring the blower fan to a halt. 
     
     
         13 . The method according to  claim 11 , wherein the frictional contact reduces a speed of the rotating blower fan and brings the rotating fan to a halt thereby providing an intrinsic safety to the rotating machine.