Flow-through sampling device

A flow-through apparatus for obtaining fluid samples from a slurry stream of phosphoric acid containing calcium sulfate solids flowing through a pipeline, said pipeline containing a pump for pressurizing the pipeline, said apparatus comprising:

• (a) an enclosed sample chamber containing inlet and outlet means for continuously admitting and withdrawing a fluid slurry to and from said sample chamber, said inlet means being in fluid communication with the high pressure side of said pipeline downstream of the pump, and said outlet means being in fluid communication with the low pressure side of said pipeline upstream of the pump, said sample chamber having an opening disposed in a side portion of the chamber for diverting a portion of the slurry flowing through the sample chamber,
• (b) means for regulating the flow of slurry to and from the sample chamber,
• (c) a filter housing sealingly engaged with the opening in the side portion of said sample chamber, said filter housing containing a filter which is in fluid communication with the slurry flowing through the sample chamber and being adapted to remove calcium sulfate solids from the slurry stream, and
• (d) means for withdrawing a filtrate sample from the filter and for backwashing the filter with water to remove solid deposits accumulating on said filter, the flow regulating means permitting the flow of fluid slurry through the apparatus during sample withdrawal and filter backwashing.