Method and apparatus for measuring particulate emissions in gas flow

Claim 1

A sampler for measuring particulate emissions in a gas flow, comprising an inlet nozzle adapted for insertion into a stack or like conduit through which a gas is flowing; pitot tube means attached to said nozzle and adapted for insertion into said stack with said nozzle for measuring the velocity of gas flowing through said stack; filter means disposed downstream of said nozzle for collecting particulate matter from said gas, said filtering means comprising an upstream housing section and a downstream housing section, said upstream and downstream housing sections being removably connected together at least at one edge thereof to facilitate rinsing of the sampler upstream of said downstream section, a screen support disposed between said upstream and said downstream sections, and a sheet of filter material supported on said screen support and removably disposed between said upstream and downstream sections; a substantially unobstructed cylindrical tube disposed between said inlet nozzle and said filter means for conducting all said gas directly from said inlet nozzle to said filter means, whereby the entire flow of gas passing through said inlet nozzle impinges on said sheet of filter material; suction pressure applying means disposed at the downstream end of said sampler for causing a flow of gas from said stack into said inlet nozzle and through said sampler; tubular means disposed between said filter means and said suction pressure applying means for conducting gas through said sampler responsive to suction pressure applied by said suction pressure applying means, said tubular means comprising a rigid tubular section attached to said filter means and a flexible tubular section disposed downstream of said rigid tubular section and attached to said suction pressure applying means, said flexible tubular section being of a length sufficient to permit separation of said suction pressure applying means from the rest of said sampler to lighten and facilitate use thereof; a flow-measuring orifice disposed in said rigid tubular section; a control panel mounted on said rigid tubular section; means mounted on said control panel and associated with said orifice for measuring the volume rate of gas passing through said sampler; means mounted on said control panel and associated with said pitot tube means for measuring the velocity of gas flowing through said stack; temperature measuring means mounted on said control panel and adapted to measure the temperature of the gas passing through said rigid tubular section; and control valve means disposed in said rigid tubular section downstream oF said orifice for adjusting the volume rate of gas passing through said sampler to make the same kinetically equivalent to said velocity of gas flowing through said stack.