Metering apparatus and method
First Claim
1. A method for accurately metering a liquid in precise increments which comprises admitting liquid to fill a chamber having inlet, outlet and intermediate collapsible positions, collapsing the inlet and outlet positions thereby to trap a determined increment of liquid in the intermediate position between the collapsed inlet and outlet positions, unloading the outlet position and expanding the same while it is in communication with the atmosphere through a discharge nozzle having an orifice thereby to suck in air through said nozzle into said chamber whereby any liquid which may have accumulated in said nozzle or at the orifice thereof is sucked back toward said chamber, and thereafter successively collapsing the intermediate and outlet positions to discharge through said nozzle a precisely determined increment of the liquid.
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Accused Products
Abstract
An elastic tube, having an inlet end adapted to communicate with liquid to be metered incrementally and an outlet end connected to a discharge nozzle having an orifice, is arranged to be collapsed at inlet, outlet and intermediate positions (at least three positions) in a programmed cycle such that liquid is trapped in the intermediate position between collapsed inlet and outlet positions, thereby determining the size of the increment. Air is drawn in through the nozzle upon unloading the inlet position, thereby to suck in any liquid which may have accumulated at the nozzle and thus to prevent any inadvertent dropping off of liquid from the nozzle. The liquid is then discharged through the nozzle by collapsing the intermediate and outlet positions in succession, and liquid is drawn in through the inlet end upon unloading the inlet and intermediate positions, thereby starting the cycle over.
75 Citations
11 Claims
- 1. A method for accurately metering a liquid in precise increments which comprises admitting liquid to fill a chamber having inlet, outlet and intermediate collapsible positions, collapsing the inlet and outlet positions thereby to trap a determined increment of liquid in the intermediate position between the collapsed inlet and outlet positions, unloading the outlet position and expanding the same while it is in communication with the atmosphere through a discharge nozzle having an orifice thereby to suck in air through said nozzle into said chamber whereby any liquid which may have accumulated in said nozzle or at the orifice thereof is sucked back toward said chamber, and thereafter successively collapsing the intermediate and outlet positions to discharge through said nozzle a precisely determined increment of the liquid.
- 4. Apparatus for metering liquids which comprises a collapsible chamber having inlet, outlet and intermediate collapsing positions and its inlet end arranged to communicate with the liquid to be metered and its outlet end connected with a discharge nozzle having an orifice, and means for collapsing and unloading said chamber, which is programmed to trap a determined quantity of liquid in the intermediate unload position between the collapsed inlet and outlet positions, to unload and expand the outlet position to draw in air through the discharge nozzle, to sequentially collapse the intermediate and outlet positions to eject the liquid, to unload and expand the inlet and intermediate positions to draw in a new increment of liquid, and to collapse the inlet position thereby to trap an accurately determined quantity of liquid in said chamber.
Specification