Method for filtering and cleaning a filter bag

Claim 1

A method of cleaning an air filter unit having at least one filtering chamber, at least one cylindrical filter bag vertically suspended within said chamber in an upright position with the open end of the filter bag facing down, air inlet means extending into the bottom of the filtering chamber and associated with the open end of said vertically suspended filter bag for passing dust laden air upwardly thereinto, first filtered air exhaust valve means connected to the top of said filtering chamber, second air exhaust valve means connected at one end to the top of said filtering chamber and at the other end to blower means connected to the air inlet means, and at least one dust collection zone positioned at the bottom of the filtering zone below the open end of the filter bag and comprising the following steps: passing dust laden air upwardly into the open end g the filter bag from the air inlet means of the filter chamber, passing the air filtered by the filter bag through the open first filtered air exhaust valve means, while the second air exhaust valve means are closed, stopping the flow of dust laden air into the air inlet means of the filtering chamber, stopping the flow of filtered air from the filtering chamber by closing the first filtered air exhaust valve means, mechanically shaking the filter bag to remove the collected dust from the interior surface of the filter bag to permit same to fall by gravity to the collection zone, removing the collected dust from the collection zone of the filtering chamber, opening the second air exhaust valve means connected to the top of said filter chamber, operating the blower means to withdraw air from within the filtering chamber and air that has previously passed through the filter bag through the second air exhaust valve means, passing the collected air to said blower means, blowing and circulating such collected and withdrawn air in the closed system into the air inlet means associated with the bottom open end of the filter bag to pass such clean air therethrough and to further clean the inside surface of the filter bag, continuing the passage of the collected and withdrawn air in a closed system for a predetermined time and until the filter bag has been cleaned to the extent desired thereby preventing dust from being discharged into the atmosphere along with the cleaned and filtered air after the initial cleaning and removal of collected dust has been completed, closing the second air exhaust valve means, opening the first filtered air valve exhaust means, and thereafter resuming the passage of the dust laden air into the air inlet means of the filtering chamber for filtering therein.

Claim 2

A method of cleaning an air filter unit having at least one filtering chamber, at least one cylindrical filter bag vertically suspended within said chamber in an upright position with the open end of the filter bag facing down, air inlet means extending into the bottom of the filtering chamber and associated with the open end of said vertically suspended filter bag for passing dust laden air upwardly thereinto, first filtered air exhaust valve means connected to the top of said filtering chamber, second air exhaust valve means connected at one end to the top of said filtering chamber and at the other end to blower means connected to the air inlet means, and at least one dust collection zone positioned at the bottom of the filtering zone below the open end of the filter bag and comprising the following steps: passing dust laden air upwardly into the open end g the filter bag from the air inlet means of the filter chamber, passing the air filtered by the filter bag through the open first filtered air exhaust valve means, while the second air exhaust valve means are closed, stopping the flow of dust laden air into the air inlet means of the filtering chamber, stopping the flow of filtered air from the filtering chamber by closing the first filtered air exhaust valve means, mechanically shaking the filter bag to remove the collected dust from the interior surface of the filter bag to permit same to fall by gravity to the collection zone, removing the collected dust from the collection zone of the filtering chamber, opening the second air exhaust valve means connected to the top of said filter chamber, operating the blower means to withdraw air from within the filtering chamber and air that has previously passed through the filter bag through the second air exhaust valve means, passing the collected air to said blower means, blowing and circulating such collected and withdrawn air in the closed system into the air inlet means associated with the bottom open end of the filter bag to pass such clean air therethrough and to further clean the inside surface of the filter bag, continuing the passage of the collected and withdrawn air in a closed system for a predetermined time and until the filter bag has been cleaned to the extent desired thereby preventing dust from being discharged into the atmosphere along with the cleaned and filtered air after the initial cleaning and removal of collected dust has been completed, closing the second air exhaust valve means, opening the first filtered air valve exhaust means, and thereafter resuming the passage of the dust laden air into the air inlet means of the filtering chamber for filtering therein.