Pneumatic pinch mechanism for a deformable tube
AssigneePrecision Dispensing Systems Limited
InventorRobert Donald Grapes
Life of this patent
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Abstract
A pinch mechanism, which can be used as part of a pump, includes a deformable tube (10) enclosed within a body (11) which has a first chamber (11a). The deformable tube (10) defines a flow passage. A second chamber (19) is coupled via passage (17) to the first chamber (11a). A piston (20) is located within the second chamber (19) and movable between first and second positions. Upon moving to the first position a pressure increase occurs in the first chamber (11a). Upon moving to the second position a negative pressure is created in the first chamber (11a). A vent means (25) is located at a point during movement of the piston (20) between the first and second positions which enables pressure equalisation within the second chamber (19) to occur.
Claims17
A pinch mechanism including a deformable tube enclosed within a body having a first chamber, the deformable tube defining a flow passage, a second chamber coupled to said first chamber, a piston located within the second chamber, the piston being movable between first and second positions such that upon moving to said first position a pressure increase occurs in said first chamber and upon moving to said second position a sub-atmospheric pressure is established in said first chamber, and vent means which includes a transfer port which at a point in the travel of the piston between the first and second positions couples parts of the second chamber which are separated by the piston to enable the second chamber to vent to a pressure higher than said sub-atmospheric pressure.
Dependencies are inferred from the claim text.