Feeder Assembly For Particle Blast System

Abstract

A particle blast system includes a feeder assembly having a rotor with a plurality of pockets formed in the peripheral surface. The transport gas flowpath includes the pockets, such that substantially all transport gas flows through the pockets. The seal adjacent the peripheral surface is actuated by the transport gas pressure to urge its sealing surface against the rotor's peripheral surface. At start up, there is no substantial pressure between the seal and the rotor, reducing start up torque requirements.

1 - 30 . (canceled)  
     
     
         31 . A feeder configured to transport blast media from a source into a transport gas flow, said feeder assembly comprising: 
 a) a rotor having a circumferential surface, said rotor being rotatable about an axis of rotation;    b) a plurality of pockets disposed in said circumferential surface, each of said plurality of pockets being cyclically disposed between a first position and a second position when said rotor is rotated about said axis; and    c) a transport gas flowpath, said transport gas flowpath having an inlet and an outlet, said inlet being configured to be connected to a source of transport gas, said inlet being in fluid communication with said outlet through those of said plurality of pockets disposed between said first and second positions.    
     
     
         32 . The feeder of  claim 31 , wherein said inlet is in fluid communication with said outlet only through said those of said plurality of pockets disposed between said first and second positions.  
     
     
         33 . The feeder of  claim 31 , wherein said plurality of pockets are arranged such that said inlet is in continuous fluid communication with said outlet when said rotor is rotated.  
     
     
         34 . A method of delivering blast media to a discharge nozzle, comprising the steps of: 
 a) providing a rotor configured to introduce said blast media into a flow of pressurized transport gas, said rotor having a first rotor surface;    b) providing a seal, said seal having a first seal surface disposed adjacent said first rotor surface;    c) starting rotation of said rotor prior to exerting any substantial force by said first seal surface on said first rotor surface;    d) after rotation of said rotor has started, exerting force by said first seal surface on said first rotor surface, forming a seal therebetween sufficient to prevent any substantial leakage of said pressurized transport gas across said formed seal.    
     
     
         35 . The method of  claim 34 , wherein said step of exerting force comprises the step of applying fluid pressure to said seal.  
     
     
         36 . The method of  claim 35 , wherein said fluid pressure is applied by said flow of pressurized transport gas.  
     
     
         37 . The method of  claim 36 , wherein said fluid pressure applied by said flow of pressurized transport gas is applied by fluid disposed in a passageway, said passageway being in fluid communication with said flow of transport gas and with said seal.  
     
     
         38 . The method of  claim 37 , wherein said fluid disposed in said passageway is pressurized transport gas.  
     
     
         39 . The method of  claim 37 , wherein a significant portion of said pressurized transport gas does not flow through said passageway.  
     
     
         40 . The method of  claim 36  wherein said flow of pressurized transport gas is controlled by a valve, there being no substantial flow of pressurized transport gas when said valve is substantially closed, further comprising the step of opening said valve to initiate said flow of pressurized transport gas at approximately the same time that rotation of said rotor is started.  
     
     
         41 . The method of  claim 36  wherein said flow of pressurized transport gas is controlled by a valve, there being no substantial flow of pressurized transport gas when said valve is substantially closed, further comprising the step of opening said valve at a time relative to said starting rotation of said rotor such that said rotor has started rotating before any appreciable torque is produced on said rotor as a result of said flow of pressurized transport gas.  
     
     
         42 - 45 . (canceled)  
     
     
         46 . A feeder configured to transport blast media from a source into a flow of transport gas, said feeder assembly comprising: 
 a) a first opening and a second opening, said first and second opening being spaced apart from each other, each opening having a respective inner diameter;    b) a rotor having a circumferential surface, said rotor being rotatable about an axis of rotation;    c) a plurality of pockets disposed in said circumferential surface, each of said plurality of pockets being cyclically disposed at a first location at which blast media is delivered thereinto, and a second location at which at least a portion of said blast media is discharged therefrom; and    d) said rotor having a first portion of said circumferential surface, said first portion having a diameter configured to be received and supported by said inner diameter of said first opening, said rotor having a second portion of said circumferential surface, said second portion having a diameter configured to be received and support by said inner diameter of said second opening, said diameter of said first portion being no larger than said inner diameter of said second opening, said circumferential surface having a maximum diameter between said first portion and said second portion no greater than the inner diameter of said second opening of said second portion    whereby said rotor may be installed in said feeder by inserting said first portion first through said second opening to a position at which said first portion is received and supported by said first opening, said second portion being received and supported by said second opening at said position.    
     
     
         47 . The feeder of  claim 46 , wherein said first and second openings are defined by respective bearings.  
     
     
         48 - 49 . (canceled)  
     
     
         50 . A feeder configured to transport blast media from a source into a flow of transport gas, said feeder comprising: 
 a) a rotor having a circumferential surface, said rotor being rotatable about an axis of rotation;    b) a plurality of pockets disposed in said circumferential surface, each of said plurality of pockets being cyclically disposed between a charge position at which blast media is introduced into said pockets and a discharge position at which blast media is discharged from said pockets;    c) a transport gas flowpath, said transport gas flowpath having an inlet and an outlet, said inlet being configured to be connected to a source of transport gas, a portion of said transport gas flowpath being disposed adjacent said discharge position such that blast media discharged from said pockets is carried therefrom by the transport gas;    d) a seal having a first surface contacting at least a portion of said circumferential surface at said discharge position; and    e) said rotor having a diameter no greater than approximately four inches.    
     
     
         51 - 54 . (canceled)  
     
     
         55 . A method of delivering blast media to a discharge nozzle, comprising the steps of: 
 a) providing a rotor configured to introduce said blast media into a flow of pressurized transport gas at a discharge station, said rotor having a first rotor surface, said rotor having a diameter no greater than approximately four inches;    b) providing a flow of transport gas; and    c) sealing between said first rotor surface and said discharge station sufficient to prevent any substantial leakage of said pressurized transport gas.    
     
     
         56 . The method of  claim 55 , wherein said transport gas has a pressure of at least approximately 30 PSIG.  
     
     
         57 . The feeder of  claim 50 , wherein said seal is configured to seal against a pressure of the transport gas of at least approximately 30 PSIG.