Methods and apparatuses for defrosting and clearing internal components of a blasting apparatus

Abstract

A particle blast apparatus comprises an interior cavity, a defrost port in fluid communication with the interior cavity, such that defrost gas is selectively introduced into the interior cavity through the defrost port; and an internal flow path extending from a source of blast media to a transport gas flow path, wherein at least a portion of the internal flow path extends through the interior cavity. A method of defrosting a particle blast apparatus that uses cryogenic materials comprises providing a particle blast apparatus comprising an interior cavity, an internal flow path extending from a source of blast media to a transport gas flow path through an interior cavity, and introducing defrost gas into the interior cavity.

What is claimed is: 
     
         1 . A particle blast apparatus comprising:
 a. an interior cavity;   b. a defrost port in fluid communication with the interior cavity, such that defrost gas is selectively introduced into the interior cavity through the defrost port; and   c. an internal flow path extending from a source of blast media to a transport gas flow path, wherein at least a portion of the internal flow path extends through the interior cavity.   
     
     
         2 . The particle blast apparatus of  claim 1  further comprising a defrost valve in fluid communication with the defrost port. 
     
     
         3 . The particle blast apparatus of  claim 1  further comprising a comminutor, wherein the comminutor is disposed within the interior cavity. 
     
     
         4 . The particle blast apparatus of  claim 3  further comprising a metering element, wherein the metering element is disposed upstream of the comminutor. 
     
     
         5 . The particle blast apparatus of  claim 4 , wherein the interior cavity is disposed within a housing, wherein the particle blast apparatus further comprises a first skirt engaged with a first side of the housing and a second skirt engaged with a second side of the housing, wherein the second side of the housing is opposite the first side of the housing. 
     
     
         6 . The particle blast apparatus of  claim 1 , wherein the interior cavity is disposed within a housing. 
     
     
         7 . The particle blast apparatus of  claim 5 , further comprising a first skirt engaged with a first side of the housing. 
     
     
         8 . The particle blast apparatus of  claim 6 , further comprising a second skirt engaged with a second side of the housing, wherein the second side of the housing is opposite the first side of the housing. 
     
     
         9 . The particle blast apparatus of  claim 1 , wherein the source of blast media is a source of cryogenic blast media. 
     
     
         10 . A method comprising:
 a. providing a particle blast apparatus, wherein the particle blast apparatus comprises
 i. an interior cavity, and 
 ii. an internal flow path extending from a source of blast media to a transport gas flow path, wherein at least a portion of the internal flow path extends through the interior cavity; and 
   b. introducing defrost gas into the interior cavity.   
     
     
         11 . The method of  claim 10 , wherein the particle blast apparatus further comprises a defrost valve and a defrost port, wherein the defrost port is in fluid communication with the defrost valve and the interior cavity, wherein the defrost gas introducing step further comprises activating the defrost valve. 
     
     
         12 . The method of  claim 10 , wherein the particle blast apparatus further comprises a metering element disposed upstream of the transport gas flow path, wherein the method further comprises causing the metering element to remain rotationally stationary. 
     
     
         13 . The method of  claim 10 , wherein the particle blast apparatus further comprises a comminutor disposed within the interior cavity, wherein the comminutor comprises a first roller and a second roller, wherein the method further comprises rotating at least one of the first roller and the second roller. 
     
     
         14 . The method of  claim 10 , wherein the particle blast apparatus further comprises a feeding rotor disposed upstream of the transport gas flow path, wherein the method further comprises causing the feeding rotor to remain rotationally stationary. 
     
     
         15 . The method of  claim 10 , wherein the particle blast apparatus further comprises a comminutor disposed within the interior cavity and a feeding rotor disposed between the comminutor and the transport gas flow path, wherein the comminutor comprises a first roller and a second roller, wherein the method further comprises rotating at least one of the first roller and the second roller while introducing defrost gas into the interior cavity and causing the feeding rotor to remain rotationally stationary while introducing defrost gas into the interior cavity. 
     
     
         16 . The method of  claim 10  further comprising stopping blast media from entering the interior cavity while introducing defrost gas into the interior cavity. 
     
     
         17 . The method of  claim 10  further comprising introducing a flow of transport gas along the transport gas flow path while introducing defrost gas into the interior cavity. 
     
     
         18 . The method of  claim 10 , wherein the particle blast apparatus further comprises:
 a. a comminutor disposed within the interior cavity, wherein the comminutor comprises a first roller and a second roller;   b. a metering element disposed upstream of the comminutor; and   c. a feeding rotor disposed intermediate the comminutor and the transport gas flow path,
 wherein the method further comprises causing the metering element to remain rotationally stationary while rotating at least one of the first roller and the second roller, causing the feeding rotor to remain rotationally stationary, introducing a flow of transport gas along the transport gas flow path, and introducing defrost gas into the interior cavity. 
   
     
     
         19 . A method comprising:
 a. providing a particle blast apparatus, wherein the particle blast apparatus comprises
 i. an interior cavity, 
 ii. a comminutor, wherein the comminutor is disposed within the interior cavity, wherein the comminutor comprises
 1. a first roller, 
 2. a second roller, and 
 3. a gap defined by an outer surface of the first roller and an outer surface of the second roller, wherein the gap has a size, 
 
  wherein the second roller is movable relative to the first roller between a first position at which the gap size is a first gap size and a second position at which the gap size is a second gap size, wherein the second gap size is greater than the first gap size; 
   b. introducing defrost gas into the interior cavity;   c. rotating at least one of the first roller and the second roller; and   d. adjusting the size of the gap.   
     
     
         20 . The method of  claim 19 , wherein introducing defrost gas into the interior cavity occurs while rotating at least one of the first roller and the second roller and adjusting the size of the gap. 
     
     
         21 . The method of  claim 20  further comprising stopping blast media from entering the interior cavity while introducing defrost gas into the interior cavity, rotating at least one of the first roller and the second roller, and adjusting the size of the gap. 
     
     
         22 . The method of  claim 21 , wherein the particle blast apparatus further comprises a feeding rotor disposed downstream of the comminutor, wherein the method further comprises rotating the feeding rotor while stopping blast media from entering the interior cavity, introducing defrost gas into the interior cavity, rotating at least one of the first roller and the second roller, and adjusting the size of the gap. 
     
     
         23 . The method of  claim 22  further comprising introducing a flow of transport gas into the particle blast apparatus while rotating the feeding rotor, stopping blast media from entering the interior cavity, introducing defrost gas into the interior cavity, rotating at least one of the first roller and the second roller, and adjusting the size of the gap.