Wet Abrasive Blasting System with Self-Venting Assembly

Abstract

The invention is directed toward wet-abrasive blasting systems used for cleaning, preparing surfaces, removing coatings, and other abrasive blasting applications. The wet abrasive basting system has a blast pot that includes a venting system. The venting system may be a self-venting system that allows gases to be vented during charging and prevents gases from accumulating in the blast pot during operation. In wet abrasive blasting systems a slurry is conveyed via a piping system, hoses, etc. to a mixer connected to a source of pressurized gas where slurry and compressed air/gas are combined and directed through the blast hose and blast nozzle.

1 .- 10 . (canceled) 
     
     
         11 . A method of operating wet abrasive blasting system, comprising:
 charging a blast pot of the wet abrasive blasting system with a liquid and solid abrasive to form a slurry, wherein the blast pot comprises:
 a cylindrical side wall, 
 an inwardly sloping top in the general shape of a basin 
 an upper most portion of an inner volume of the blast pot defined between the underside of the inwardly sloping top and an inside top of the cylindrical side wall of the blast pot, 
 an outlet connected to the cylindrical side wall at the upper most portion of an inner volume of the blast pot, and 
 a self-venting assembly, wherein the self-venting assembly is connected to the outlet in the cylindrical side wall; 
   sealing the blast pot during the final stage of charging the blast pot with liquid;   after sealing the blast pot, filling the blast pot with additional liquid and removing substantially all of the trapped air from within the blast pot through the self-venting assembly until the fluid level fills the tank and the self-venting, assembly is sealed; and   pressurizing the blast pot with a fluid pump.   
     
     
         12 . The method of  claim 11 , wherein the wet abrasive blasting system comprises:
 a mixer;   a blast hose in fluid communication with the mixer;   a slurry piping system connecting the bottom outlet of the blast pot to the mixer; and   a pressurized air piping system capable of connecting a source of pressurized air to the mixer.   
     
     
         13 . The method of  claim 11 , wherein the self-venting assembly, comprises:
 an automatic vent valve that operates based upon a sensor measuring air within the blast pot.   
     
     
         14 . The method of  claim 13 , wherein the automatic vent valve opens to release air from the blast pot that may become trapped in the upper most portion of the blast pot, without releasing a significant amount of fluid, through the automatic vent valve until the fluid level fills the blast pot and the automatic vent valve is automatically sealed to prevent escape of liquid. 
     
     
         15 . The method of  claim 13 , wherein a pipe connects the outlet in the cylindrical side wall and the automatic vent valve. 
     
     
         16 . The method of  claim 11 , wherein the self-venting assembly comprises one of a float type vent valve, a diaphragm-type vent valve or an electronic vent valve. 
     
     
         17 . The method of  claim 11 , wherein air accumulating in the blast pot after purging due to worn pump seals, a suction leak in the fluid pump's inlet hose or from a fluid source that includes trapped air bubbles is vented through the self-venting assembly. 
     
     
         18 . The method of  claim 11 , wherein the self-venting assembly, comprises:
 an automatic vent valve that operates based upon a sensor measuring air within the blast pot, wherein the automatic vent valve opens to release air from the blast pot that may become trapped in the upper most portion of the inner volume, without releasing a significant amount of fluid, through the automatic vent valve until the fluid level fills the tank and the automatic vent valve is automatically sealed to prevent escape of liquid, wherein the automatic vent valve is a float type vent valve comprising a chamber, a vent seal, a float and a seat, wherein if air enters the automatic vent valve, the float moves to a lower position to allow the air or other gases to escape the chamber.   
     
     
         19 . The method of  claim 11 , wherein sealing the blast pot comprises closing a spring-loaded bung. 
     
     
         20 . The method of  claim 19 , wherein charging the blast pot of the wet abrasive blasting system with the liquid and the solid abrasive comprises charging the blast pot through a sealable inlet hole in the inwardly sloping top. 
     
     
         21 . The method of  claim 20 , wherein during charging air may escape through the sealable inlet hole in top. 
     
     
         22 . The method of  claim 20 , wherein during charging air may escape through the sealable inlet hole in top until a water level reaches the seal. 
     
     
         23 . The method of  claim 13 , wherein the automatic vent valve prevents the accumulator effect.