Abstract: A gas sampling apparatus including a flexible, substantially gas-impervious, closed bag and a valve assembly mounted in a wall of the bag for providing control of gas flow between the interior and exterior of the bag. The valve assembly includes a valve body mounted in the bag wall for providing a first gas conduit to and from said interior of the bag, and a valve stem for providing a second gas conduit, the stem terminating at one end in a ball mounted on the valve body. The stem is movable about the ball between an opened position in which the gas conduits are in communication with one another and the bag may be filled or emptied through the coupled conduits, and a closed position in which the ball seals the first conduit. A valve cap is provided for capturing the stem at variable pressures between the valve body and the cap. The cap has a slot in one side in which the stem is movable tranversely to its long axis between its opened and closed positions.

Abstract: The calibrator device is used for calibrating the flow indicator (rotometer) of an air pollution sampling instrument known as a high volume air sampler which determines the concentration of the total suspended particulate in the ambient atmosphere. The calibrator is of cylindrical shape having an annular passage and centrally disposed knob at one end and a pair of aperture plates at the other end, one of which is fixed in position and the other one of which is rotatable by means of the knob. Each calibrator defines a flow characteristic represented by a graph of flow versus orifice pressure, and by setting the flow resistance at different sequential values by rotation of the knob a plot is established of true air flow in cubic feet per minute (cfm) versus observed flow meter reading.