Abrasive blast system

Abstract

A vapor abrasive blast system includes a compressor for generating compressed air, a water pump for pumping a water stream to a pressure vessel to pressurize the pressure vessel. A control valve is disposed upstream of the pressure vessel and is configured to control the flow of water from the water pump to the pressure vessel to thereby control the flow of blast slurry downstream out of the pressure vessel.

1 . An abrasive blast system comprising:
 a water pump configured to pump a flow of water from a water source to a pressure pot through a water line;   an air supply line extending from an air source;   a media line extending from the pressure pot to the air supply line;   a blast line extending downstream from a junction of the media line and the air supply line to a nozzle;   a control valve configured to shift between an open state and a closed state to control the flow of water to the pressure pot and thereby control the flow of blast slurry from the pressure pot to the media line; and   a blast control switch controllable between an activated state and a deactivated state and configured to actuate the control valve between the open state and the closed state.   
     
     
         2 . The abrasive blast system of  claim 1 , wherein the media line is connected to the pressure pot at a first location and the media line is connected to the junction at a second location, and wherein the second location is disposed at higher elevation than a maximum water level in the pressure pot. 
     
     
         3 . The abrasive blast system of  claim 1 , wherein the control valve is disposed on a portion of the water line between the water pump and the pressure pot. 
     
     
         4 . The abrasive blast system of  claim 1 , wherein the control valve is configured to control activation of the water pump to thereby control the flow of water to the pressure pot. 
     
     
         5 . The abrasive blast system of  claim 4 , further comprising:
 a system line extending from the air supply line to the water pump, the system line configured to provide compressed air from the air supply line to the water pump to power the water pump;   wherein the control valve is a valve disposed on the system line between the air supply line and the water pump, the control valve configured to control the flow of compressed air to the pump.   
     
     
         6 . The abrasive blast system of  claim 4 , wherein the control valve is configured to mechanically interact with the water pump to prevent the water pump from pumping the flow of water when the control valve is in the closed state. 
     
     
         7 . The abrasive blast system of  claim 1 , further comprising:
 a blast air controller configured to control a blast air flow through the air supply line;   wherein the blast control switch is configured to actuate the blast air controller between an open controller state and a closed controller state.   
     
     
         8 . The abrasive blast system of  claim 7 , further comprising:
 a system valve disposed on a system line branching from the air supply line;   a blast control line extending from the system valve to the blast air controller;   a pressurizing control line extending from the system valve to the control valve;   wherein the system valve is configured to direct the system air flow to the blast control line based on the blast control switch being in the activated state and to direct the system air flow to the pressurizing control line based on the blast control switch being in the deactivated state.   
     
     
         9 . The abrasive blast system of  claim 8 , further comprising:
 a first pneumatic control line extending from the air supply line to the blast control switch;   a second pneumatic control line extending from the blast control switch to the system valve;   wherein the blast control switch fluidly connects the first pneumatic control line to the second pneumatic control line when in the activated state such that compressed air from the air supply line can flow to and actuate the system valve.   
     
     
         10 . The abrasive blast system of  claim 8 , wherein the blast air controller is normally-closed such that the system air flow actuates the blast air controller to the open controller state, and the control valve is normally-open such that the system air flow actuates the control valve to the closed state. 
     
     
         11 . The abrasive blast system of  claim 1 , further comprising:
 control logic configured to implement a delay between the control valve shifting between the open state and the closed state and the blast air controller shifting between the open controller state and the closed controller state;   wherein the control logic causes the blast air controller to shift to the open controller state before the control valve shifts to the open state; and   wherein the control logic causes the blast air controller to shift to the closed controller state after the control valve shifts to the closed state.   
     
     
         12 . The abrasive blast system of  claim 1 , wherein there is no valve disposed downstream of the pressure pot to control the flow of blast slurry through any one of the media line, the blast line, and the nozzle during blasting. 
     
     
         13 . A method comprising:
 generating a compressed air flow and directing the compressed air flow to an air supply line extending to a junction with a media line, the media line extending from a pressure pot and being configured to convey a blast slurry flow to the junction from the pressure pot;   pumping, with a water pump, a pressurizing water flow to the pressure pot through a water line extending between the water pump and the pressure pot; and   controlling, with a blast control switch, actuation of a control valve between an open state and a closed state to thereby control the pressurizing water flow to the pressure pot and the blast slurry flow through the media line.   
     
     
         14 . The method of  claim 13 , wherein:
 the control valve is disposed on the water line; and   the control valve allows the pressurizing water flow to flow to and pressurize the pressure pot when in the open state, and the control valve prevents the pressurizing water flow from flowing to and pressurizing the pressure pot when in the closed state.   
     
     
         15 . The method of  claim 13 , wherein:
 the control valve is disposed on a pump air supply line supplying pump air to the water pump to power the water pump; and   the control valve allows the pump air to flow to and power the water pot when in the open state, and the control valve prevents the pump air from flowing to and powering the water pump when in the closed state.   
     
     
         16 . The method of  claim 13 , wherein:
 the control valve mechanically interacts with the water pump to control pumping by the water pump; and   the control valve restrains reciprocation of a pump component of the water pump when in the closed state to prevent the water pump from pumping water to the pressure pot, and allows reciprocation of the pump component when in the open state to allow the water pump to pump the water to the pressure pot.   
     
     
         17 . The method of  claim 13 , further comprising:
 controlling, with the blast control switch, actuation of a blast air controller disposed on the air supply line between an open controller state, where the blast air controller allows the compressed air to flow to the junction through the air supply line, and a closed controller state, where the blast air controller prevents the compressed air from flowing to the junction through the air supply line;   wherein the blast air controller is configured to be in the open controller state when the control valve is in the open state, and the blast air controller is configured to be in the closed controller state when the control valve is in the closed state.   
     
     
         18 . The method of  claim 17 , further comprising:
 delaying shifting of the control valve to the open state until after the blast air controller shifts to the open controller state; and   delaying shifting of the blast air controller to the closed controller state until after the control valve shifts to the closed state.   
     
     
         19 . A control system for a vapor abrasive blast system having a pressure pot that stores a supply of blast slurry, a compressor for providing a flow of compressed air through an air supply line to a blast line, and a water pump for pumping water to the pressure pot to thereby pressurize the pressure pot and drive the blast slurry downstream out of the pressure pot through a media line to the blast line where the blast slurry can be entrained in the compressed air and carried out of a nozzle, the control system comprising:
 a control valve configured to shift between an open state and a closed state to control the water flow to the pressure pot from the water pump, wherein the control valve is configured to prevent the water from flowing to and pressurizing the pressure pot when in the closed state and to allow the water to flow to and pressurize the pressure pot when in the open state;   a blast air controller disposed on the air supply line upstream of the blast line, the blast air controller configured to shift between an open controller state and a closed controller state to control the compressed air flow to the blast line, wherein the blast air controller is configured to prevent the compressed air from flowing to the blast line when in the closed controller state and to allow the compressed air to flow to the blast line when in the open controller state; and   a blast control switch configured to control the control valve between the open state and the closed state, and further configured to control the blast air controller between the open controller state and the closed controller state;   wherein the flow of blast slurry out of the pressure pot is activated and deactivated by the water flow to the pressure pot.   
     
     
         20 . The control system of  claim 19 , wherein there is no valve disposed downstream of the pressure pot to control the flow of blast slurry through any one of the media line, the blast line, and the nozzle during blasting