Sampling valve including sample ejection means

In a sample metering device capable of delivering a predetermined amount of particulate matter to a location and comprising slide valve means including a movable element arranged for limited slidable movement, means within said movable element defining a reservoir, means defining a flow path communicating to and from said reservoir for loading same from a source of particulate matter, said movable element being translatable for trapping a volume of said particulate matter within said reservoir, thermal expansion means carried by said movable element and communicating directly to said reservoir, fine aperture means formed in said movable element and communicating with said reservoir, passage means leading to said location, said thermal expansion means capable of being energized to expand for ejecting said predetermined amount from said reservoir the inprovement comprising blocking means interposed between said fine aperture means and said passage means for isolating said reservoir and fine aperture means from said passage means and said location at least during the loading of said reservoir and carrying a passageway, said blocking means arranged to permit communication between said fine aperture means and said passage means only during energization of said expansion means.

In a particle study device wherein particulate matter in a fluid suspension is passed through a sensing zone, sample metering means including a reservoir, means defining a flow path for leading a sample particulate matter to and from said reservoir, an ejection port communicating to said reservoir, thermal expansion means within said sample metering means positioned in direct communication with said reservoir and operative in response to a control signal to expand and thereby to eject a predetermined amount of particulate matter from said reservoir to and through said ejection port, means for receiving said ejected amount and leading same to the sensing zone;

• the improvement comprising means for selectively isolating the reservoir from the receiving means and sensing zone except during ejection of the predetermined amount.

In a particle study device wherein a particulate matter in liquid suspension is passed through a sensing zone, sample metering valve means including a stationary element and a slidably movable element sealingly engaged therewith for limited relative movement therewith, a reservoir defined within said movement element and means defining a flow path through said elements and communicating with said reservoir for leading said particulate matter from a source to said reservoir in one condition of said elements whereby a predetermined amount of said particulate matter is trapped within said reservoir, selectively operable thermal expansion means carried by said movable element and communicating directly with the trapped content of said reservoir, an ejection port formed in said movable member and communicating to the reservoir, means coupling said sample metering valve means with a sensing zone and including a receiving chamber having an entrance for receiving said predetermined amount and for introducing diluent from a source thereof to said chamber defining a flow sheath leading said predetermined amount to and through the sensing zone;

• the improvement comprising slidable means selectively for sealing off the ejection port from the entrance during said trapping of said sample and thereafter establishing communication between the ejection port and the entrance.