Separation system for polymeric blast media

Claim 1

A system for recovering and cleaning for reuse a contaminated lightweight material employed as a gas-entrained abrasive for cleaning workpiece surfaces of contaminants such as dirt, corrosion, scale and the like, where the abrasive has a specific gravity less than the heavier contaminants and greater than the lightweight contaminants combined therewith as a result of the cleaning operation, comprising: a first vacuum system for re-entraining spent, contaminated abrasive into a transporting gas stream from a work site, said first vacuum system discharging the gas stream in a generally vertical direction; a closed-top separator tank including a bottom portion for collection and discharge of said abrasive and an upper portion, said upper portion including: a first closed-end cylinder including a target surface toward which said gas stream containing the contaminated abrasive is directed upon discharge from said first vacuum system, said first closed-end cylinder having a shape to cause a disbursal and general reversal in direction of travel of the abrasive and contaminants, said first closed-end cylinder including a substantially unrestricted bottom discharge opening through which the abrasive and contaminants fall downwardly at a substantially reduced speed of travel toward said bottom portion of said separator tank with the lightweight abrasive and contaminants therein remaining substantially suspended while the bulk of the abrasive and heavier contaminants travel to said bottom portion of said separator tank for removal; and a second closed-end cylinder of smaller diameter than said separator tank, said second cylinder having an opening open to said tank upper portion interior at its bottom at a position lateral of said first closed-end cylinder opening communicating with a substantially dead air space of said separator tank and having a sidewall tangential discharge for discharging said gas stream contaminated with lightweight contaminants from the upper portion of said separator tank interior, said second cylinder opening being out of direct path of the falling bulk of the abrasive and heavier contaminants to capture the suspended lightweight contaminants and lightweight abrasive particles; and a second vacuum system for evacuating said separator tank through said second cylinder tangential exit, wherein a gentle swirling motion is imparted to the lightweight abrasive particles and contaminants throughout said separator upper portion by operation of the second cylinder tangential discharge, such that said exiting gas sweeps the lightweight contaminants from the cascading heavier abrasives falling to the bottom of the tank, and said abrasives, cleaned of said lightweight contaminants are discharged from said tank bottom discharge.

Claim 2

A system for recovering and cleaning for reuse a contaminated lightweight material employed as a gas-entrained abrasive for cleaning workpiece surfaces of contaminants such as dirt, corrosion, scale and the like, where the abrasive has a specific gravity less than the heavier contaminants and greater than the lightweight contaminants combined therewith as a result of the cleaning operation, comprising: a first vacuum system for re-entraining spent, contaminated abrasive into a transporting gas stream from a work site, said first vacuum system discharging the gas stream in a generally vertical direction; a closed-top separator tank including a bottom portion for collection and discharge of said abrasive and an upper portion, said upper portion including: a first closed-end cylinder including a target surface toward which said gas stream containing the contaminated abrasive is directed upon discharge from said first vacuum system, said first closed-end cylinder having a shape to cause a disbursal and general reversal in direction of travel of the abrasive and contaminants, said first closed-end cylinder including a substantially unrestricted bottom discharge opening through which the abrasive and contaminants fall downwardly at a substantially reduced speed of travel toward said bottom portion of said separator tank with the lightweight abrasive and contaminants therein remaining substantially suspended while the bulk of the abrasive and heavier contaminants travel to said bottom portion of said separator tank for removal; and a second closed-end cylinder of smaller diameter than said separator tank, said second cylinder having an opening open to said tank upper portion interior at its bottom at a position lateral of said first closed-end cylinder opening communicating with a substantially dead air space of said separator tank and having a sidewall tangential discharge for discharging said gas stream contaminated with lightweight contaminants from the upper portion of said separator tank interior, said second cylinder opening being out of direct path of the falling bulk of the abrasive and heavier contaminants to capture the suspended lightweight contaminants and lightweight abrasive particles; and a second vacuum system for evacuating said separator tank through said second cylinder tangential exit, wherein a gentle swirling motion is imparted to the lightweight abrasive particles and contaminants throughout said separator upper portion by operation of the second cylinder tangential discharge, such that said exiting gas sweeps the lightweight contaminants from the cascading heavier abrasives falling to the bottom of the tank, and said abrasives, cleaned of said lightweight contaminants are discharged from said tank bottom discharge.