Dilution system for particle analyzer

Claim 2

In apparatus of the type described the combination with means defining a sensing area, means for circulating a sample fluid through said sensing area, and means for filtering said fluid after it has passed through said sensing area of means defining a generally closed circulation flow path for said fluid from and back to said sensing area and comprising, in combination, means defining a flow passage downstream of said filter means for directing the fluid after it has passed through said filter means to said sensing area, means defining a sample inlet open to the ambient for introducing a sample volume of fluid into said closed circulation and into said sensing area, and means defining a restricted, variable exhaust from said closed circulation path whereby an adjustable volume of flowing fluid can be discharged into the ambient and corresponding fresh sample of fluid will be drawn from the ambient into the sensing area.

Claim 3

In apparatus of the type described, the combination with means defining a sensing area, means including an inlet open to the ambient and operative to draw a sample amount of fluid from the ambient and direct it into said sensing area, means for circulating a predetermined volume of fluid through said sensing area, and filter means for cleaning said flowing fluid after it has passed through said sensing area of means for diluting the sample drawn in through said inlet means and comprising, in combination, conduit means connecting the flow from said filter means to said inlet means so that fluid passed through said filter means can be redirected to said sensing area, and means defining an adjustable, restricted outlet from said conduit means whereby a measured volume of flowing fluid can be discharged into the ambient with the remainder of said flowing fluid being directed to said inlet means and a fresh sample of fluid corresponding to the discharged measured volume will be drawn through said inlet means into said reciRculated fluid for passage through said sensing area.

Claim 4

In apparatus of the type described, the combination with means defining a sensing area, means including an inlet open to the ambient and operative to draw a sample amount of fluid from the ambient and direct it into said sensing area, means for circulating a predetermined volume of fluid through said sensing area, and filter means for cleaning said flowing fluid after it has passed through said sensing area of means for diluting the sample drawn in through said inlet means and comprising, in combination, conduit means connecting the flow from said filter means to said inlet means so that fluid passed through said filter means can be redirected to said sensing area, and means defining an adjustable, restricted outlet from said conduit means whereby a measured volume of flowing fluid can be discharged into the ambient with the remainder of said flowing fluid being directed to said inlet means and a fresh sample of fluid corresponding to the discharged measured volume will be drawn through said inlet means into said reciRculated fluid for passage through said sensing area.

Claim 5

The combination of claim 2 wherein said means defining said adjustable, restricted outlet includes a conduit open to the ambient and a valve member in said conduit adjustable to regulate the amount of discharge flow through that conduit to the ambient.

Claim 6

The combination of claim 2 wherein said inlet means includes an inlet tubular member open to the ambient to be sampled and extending into said sensing area, and including a second tubular member concentric with said inlet tubular member and communicating with said conduit means so that the recirculated flowing fluid is directed to the annular space between said inlet tubular member and said second tubular member, said second tubular member also being directd into said sensing area and said fresh sample volume is injected directly into the center of said flowing fluid.

Claim 7

The combination of claim 3 wherein said conduit and said adjustable outlet to said ambient are positioned downstream of said filter means.

Claim 8

The combination of claim 5 wherein said conduit means and said adjustable outlet mechanism comprises an adapter connectable to said apparatus including said sensing area, said fluid circulating means, and said filter means.

Claim 9

The combination with a particle analyzer having an inlet open to the ambient, a sensing area into which said inlet opens to direct a sample volume, pump means for circulating fluid medium through said sensing area from said inlet and through an outlet to said ambient, and filter means downstream of said sensing area for cleaning said sample volume before passage through said outlet, of an adapter assembly comprising in combination, means communicating with said outlet to receive the flowing fluid after it leaves said filter medium, an injector assembly including said inlet means, conduit means connecting said means communicating with said outlet to said injector assembly for directing said flowing fluid back through said injector assembly to thereby define a generally closed recirculating system, and means associated with said conduit means and defining an adjustable outlet to said ambient whereby a measured portion of said circulating fluid medium can be discharged into said ambient and a corresponding amount of fresh sample fluid medium will be drawn into said sensing area and mixed with said recirculated clean fluid medium.

Claim 10

The combination with a particle analyzer having an inlet open to the ambient, a sensing area into which said inlet opens to direct a sample volume, pump means for circulating fluid medium through said sensing area from said inlet and through an outlet to said ambient, and filter means downstream of said sensing area for cleaning said sample volume before passage through said outlet, of an adapter assembly comprising in combination, means communicating with said outlet to receive the flowing fluid after it leaves said filter medium, an injector assembly including said inlet means, conduit means connecting said means communicating with said outlet to said injector assembly for directing said flowing fluid back through said injector assembly to thereby define a generally closed recirculating system, and means associated with said conduit means and defining an adjustable outlet to said ambient whereby a measured portion of said circulating fluid medium can be discharged into said ambient and a corresponding amount of fresh sample fluid medium will be drawn into said sensing area and mixed with said recirculated clean fluid medium.

Claim 11

The combination of claim 7 including a flow meter upstream of said adjustable valve to measure the amount of discharge into said ambient.

Claim 12

The combination of claim 7 wherein said injector assembly includes an inlet tubular member open to the ambient to be sampled and extending into said sensing area whereby a sample volume can be drawn into the apparatus and discharged into the sensing area, a second tubular member concentric with said inlet tubular member and communicating with said conduit means whereby the recirculated flowing fluid medium is directed to the annular space between said inlet tubular member and said second tubular member, said second tubular member also being directed into said sensing area so that said recirculated fluid medium is directed into said sensing area and said fresh sample volume is injected directly into the center of said flowing fluid medium.

Claim 13

The combination of claim 7 wherein said pump means circulates a predetermined volume of fluid medium.