Ambient Air Backflushed Filter Vacuum

Abstract

A vacuum cleaning machine has a cannister with an inlet port and at least two outlet ports. At least two filters are disposed inside of the cannister, one in pneumatic communication through each of the outlet ports. At least two valves are disposed outside of the cannister. Each valve is in pneumatic communication between a vacuum source and an outlet port so as to permit air to be drawn by the vacuum source from the inlet port simultaneously through the filters. A controller operates the valves to switch the filters from the vacuum source to ambient air so as to permit ambient air to be sequentially intermittently drawn through corresponding valves and filters into the cannister. Preferably, the controller includes a timing mechanism for setting the delay time of the sequential valve operation and a timing mechanism for setting the intermittent time of connection of each filter to ambient air.

What is claimed is: 
     
         1 . A vacuum cleaning machine comprising:
 a canister disposed in ambient air and having an inlet port accessing ambient air and at least two outlet ports;   at least two filters disposed inside of said canister, one in pneumatic communication through a corresponding one of each of said outlet ports;   a vacuum source disposed outside of said canister and in said ambient air;   at least two valves disposed outside of said canister and in said ambient air, each said valve having three ports, a first of said three ports being always open and second and third of said three ports being switchable so that, when one of second and third ports is opened, the other of said second and third ports is closed;   each said first valve port being connected to a corresponding one of said filters through its corresponding one of said canister outlet ports for pneumatic communication between its said corresponding valves and filters;   each said second valve port being connected for pneumatic communication between said valve and said vacuum source;   each said third valve port being in pneumatic communication between said valve and said ambient air; and   a mechanism switching each of said valves one at a time from a second valve port opened condition to a third valve port opened condition whereby each valve in said second port opened condition simultaneously permits said ambient air to be drawn by said vacuum source from its said inlet port through its corresponding one of each of said filters to collect dust particles in said canister on said filters and a valve in said third port opened condition permits said ambient air to be drawn by said vacuum source through its respective said third valve port to dislodge dust particles collected on said filter into said canister.   
     
     
         2 . A vacuum cleaning machine according to  claim 1 , said canister further comprising a plate having said at least two outlet ports therethrough, said plate closing an open end of said canister. 
     
     
         3 . A vacuum cleaning machine according to  claim 2  further comprising a cover seated on said canister over said plate with said valves in said ambient air inside said cover. 
     
     
         4 . A vacuum cleaning machine according to  claim 1  further comprising a duct connecting said first valve port to its said corresponding one of said at least two outlet ports. 
     
     
         5 . A vacuum cleaning machine according to  claim 1  further comprising a duct connecting said second valve port to said vacuum source. 
     
     
         6 . A vacuum cleaning machine according to  claim 1 , said vacuum source having a central housing, said central housing containing air at a lower pressure than a pressure of said ambient air. 
     
     
         7 . A vacuum cleaning machine according to  claim 6 , each said second valve port further comprising a duct connected to said central housing of said vacuum source. 
     
     
         8 . A vacuum cleaning machine according to  claim 1 , an outer wall of at least one of said at least two filters being exposed to a corresponding outer wall of another of said at least two filters. 
     
     
         9 . A vacuum cleaning machine according to  claim 1 , said canister being cylindrically shaped. 
     
     
         10 . A vacuum cleaning machine according to  claim 9 , each of said at least two filters having a filtering wall exposed to a corresponding filtering wall of each of the other of said at least two filters.