In-stack filter cell

Claim 1

A filter cell sampling device for collecting particulate matter directly within a stack or duct during an isokinetic flow of gas containing the particulate matter through the stack or duct, comprising: a generally tubular closed housing of two generally hemi-cylindrical separable halves for direct insertion into the stack or duct and having an elongated inlet chamber and an elongated outlet chamber, the inlet and outlet chambers both extending substantially the axial length of the cylindrical housing; inlet means for drawing the flow of gas into said housing, said inlet means including an inlet nozzle at the upstream end of and communicating with the inlet chamber of said housing in one end thereof; a preweighed filter means in sheet form in said housing extending substantially the length thereof and disposed downstream of the inlet chamber parallel to and lying between the elongated inlet and outlet chambers and parallel to the flow of gas entering said housing from said inlet at the end of the inlet chamber, said filter being disposed upstream from the outlet chamber and being formed of a heat and moisture resistant material, and means in said housing to support and to hold said filter in sheet form; sealing means between the halves of said housing for ensuring a leakless seal; and outlet means for directing the flow of gas out of said housing, said outlet means being disposed downstream of the outlet chamber in the end of the housing generally opposite the location of said inlet means to direct the flow of gas through the outlet chamber generally parallel to said filter means.