Abstract A liquid is filtered by first delivering it to a first enclosed chamber having a first filter bed, and passing the liquid downwardly through the bed. The liquid is then delivered to a backwash storage chamber above the first bed, and then to a second enclosed chamber containing a second bed. The liquid is passed downwardly through the second bed, and is then delivered to service. The apparatus includes means defining a first filter chamber containing a first filter bed, means defining a second filter chamber containing a second filter bed, and means defining a backwash storage chamber above the filter chambers. Suitable pipe means are provided for delivering liquid in series through the first filter bed, the backwash storage chamber, and the second filter bed. Pipe means are also provided for backwashing the first and second filter beds with water from the backwash storage chamber. The preferred embodiment also provides means for gas-scouring the filter beds.
The method as defined in claim 1 further including the step of scouring said first bed by passing a stream of gas under pressure upwardly through said first filter bed prior to said backwashing.
Claim 2
Dependent Claim
35 words
The method as defined in claim 2 further including the step of scouring said second filter bed by passing a stream of gas under pressure upwardly through said second filter bed prior to said backwashing.
Claim 3
Dependent Claim
178 words
Improved filtration apparatus comprising: means defining a first filter chamber having an upper inlet side and a lower outlet side with a first filter bed therebetween; means defining a second filter chamber having an upper inlet side and a lower outlet side with a second filter bed therebetween; means defining a backwash storage chamber above said first and second filter chambers, said backwash storage chamber supplying backwash liquid under sufficient pressure to force said liquid upwardly through either of said filter beds; first pipe means for delivering liquid to said upper inlet side of said first filter chamber; second pipe means providing communication between said lower outlet side of said first filter chamber and said backwash storage chamber; third pipe means for delivering liquid from said backwash chamber to said upper inlet side of said second filter chamber; fourth pipe means for delivering liquid from said lower outlet side of said second filter chamber to service; and fifth pipe means for delivering liquid from said backwash storage chamber to said lower outlet side of said second filter chamber.
Claim 4
Dependent Claim
41 words
The filtration apparatus as defined in claim 4 wherein said fourth pipe means is an inverted U-shaped siphon, the top of said siphon being positioned above the level of said second filter bed, said siphon having air vent means communicating therewith.
Claim 5
Dependent Claim
16 words
The filtration apparatus as defined in claim 4 wherein said second filter bed comprises activated carbon.
Claim 6
Dependent Claim
18 words
The filtration apparatus as defined in claim 4 wherein said second filter bed comprises an ion exchange resin.
Claim 7
Dependent Claim
27 words
The filtration apparatus as defined in claim 4 further including means for delivering a gas under pressure to said lower outlet side of said first filter bed.
Claim 8
Dependent Claim
27 words
The filtration apparatus as defined in claim 8 further including means for delivering a gas under pressure to said lower outlet side of said second filter bed.