Pleated air filter with reverse pulsating air flow cleaning

Abstract

An air filter assembly has a pleated filter cartridge for filtering out dust from the air, this unit being fabricated of a suitable paper material. The cartridge is in the form of a receptacle having an open top, a closed bottom and closed sides which run entirely there around. Pleats are formed in the sides of the cartridge. The pleats are separated from each other by an adhesive bead which may be formed from a hot melt material. In the filtering cycle air is drawn out by a blower from the inside of the cartridge thereby drawing air from the outsides through the pleated sides which filter our dirt. The filtered air is fed from the cartridge to an area requiring clean air. Periodically, the filter is automatically cleaned by compressed pulsating air which is fed to the interior of the cartridge drives through the pleated sides, thereby blowing off dirt accumulated on the cartridge.

We claim:  
     
         1 . An air filter assembly comprising: 
 a filter cartridge in the form of a container having an open top and a side portion fabricated of an air filter material running around the entire side of said cartridge, said side portion having pleats formed therein, and beads separating said pleats from each other;    a blower for drawing air through said cartridge from the outer walls of said side portion, said side portion filtering said air, said blower further drawing said filtered air out of said cartridge; and    means for driving pulsating pressurized air into said cartridge and out through said side portion thereby driving dirt from the outer walls of said cartridge side portion.    
     
     
         2 . The air filter assembly of  claim 1  wherein said means for driving air into said cartridge and out through the side portion thereof comprises a source of compressed air and a valve connected to said compressed air source for releasing said compressed air into said cartridge.  
     
     
         3 . The air filter assembly of  claim 2  wherein said means for driving air into said cartridge and out through the side portion thereof additionally comprises a timer control for opening said closing said valve at a predetermined rate.  
     
     
         4 . The air filter assembly of  claim 3  wherein said means for driving said air into said cartridge and out through the side portion thereof comprises a sensor for sensing a predetermined drop in the pressure of the air entering the cartridge, said sensor operating said timer control in response to the sensing of said predetermined pressure drop.  
     
     
         5 . The air filter assembly of  claim 1  wherein said filter cartridge is cylindrical in shape.  
     
     
         6 . A method for automatically cleaning dust from the filter cartridge of an air filter wherein the filter element has an outer wall portion surrounding a hollow central portion comprising the steps of: 
 providing a source of compressed air; and    feeding said compressed air in a pulsating manner into the central portion of said filter cartridge;    the compressed air passing through the filter outer wall portion to drive dust therefrom.    
     
     
         7 . The method of  claim 6  wherein the pulsating feeding of said compressed air into the central portion of said filter is done in response to a programmed timer.  
     
     
         8 . An air filter assembly comprising: 
 a filter cartridge in he form of a container having an open top and a side portion fabricated of an air filter material running around the entire side of said cartridge, said side portions having pleats formed therein, and beads separating said pleats from each other;    a blower for drawing air through said cartridge from the outer walls of said side portion, said side portion filtering said air, said blower further drawing said filtered air out of said cartridge and feeding said air to a predetermined clean air area;    a reservoir;    compressed air stored in said reservoir;    a valve connected to the output of said reservoir;    a blow pipe having a nozzle connected to the output of said valve, said blow pipe feeding air into the interior of said filter cartridge, and    an automatic timer control for effecting pulsed feeding of said compressed air at a predetermined rate.    
     
     
         9 . The air filter of  claim 8  wherein said automatic timer is set to change the pulsing rate at which the compressed air is fed.  
     
     
         10 . The air filter of  claim 8  and further including pressure sensors for sensing the pressure differential between the inside and outside walls of said filter cartridge, the outputs of said pressure sensors being fed to said automatic timer, said automatic timer being programmed to initiate the pulsed feeding of said compressed air when said pressure differential reaches a predetermined value and to terminate said pulsed feeding when the pressure differential drops below a predetermined value.  
     
     
         11 . The air filter of  claim 9  and further including pressure sensors for sensing the pressure differential between the inside and outside walls of said filter cartridge, the outputs of said pressure sensors being fed to said automatic timer, said automatic timer being programmed to initiate the pulsed feeding of said compressed air when said pressure differential reaches a predetermined value and to terminate said pulsed feeding when said pressure differential falls below a predetermined value.