초록 ▼

Pump heads comprising at least two gear-pump chambers are disclosed. Each chamber comprises a housing which defines a corresponding pump cavity. Each cavity contains a driving gear and at least one driven gear and has a separate inlet and outlet. The pump cavities are hydraulically interconnected by

Pump heads comprising at least two gear-pump chambers are disclosed. Each chamber comprises a housing which defines a corresponding pump cavity. Each cavity contains a driving gear and at least one driven gear and has a separate inlet and outlet. The pump cavities are hydraulically interconnected by a fluid conduit allowing passage whenever the pump chambers are pumping a fluid so as to generate a higher pressure in one cavity relative to the other cavity, of the fluid from the higher-pressure cavity to the lower-pressure cavity sufficient to maintain hydraulic prime of both cavities. The invention is particularly useful for ink jet printing applications.

대표청구항 ▼

A hydraulic circuit for supplying liquid ink to a continuous printing head for application to an object and for collecting and recycling ink that has passed through the printing head but not applied to the object, the circuit comprising: (a) a printing head adapted to apply liquid ink to an object;

A hydraulic circuit for supplying liquid ink to a continuous printing head for application to an object and for collecting and recycling ink that has passed through the printing head but not applied to the object, the circuit comprising: (a) a printing head adapted to apply liquid ink to an object; (b) a reservoir for containing a supply of liquid ink for use by the printing head; (c) a gutter for collecting ink that has passed through the printing head but is not intended to be applied to the object; (d) A multiple-chamber pump head comprising a first gear-pump chamber and a second gear-pump chamber, the first gear-pump chamber comprising a first housing defining a first pump cavity; a first driving gear situated within the first pump cavity and rotatable about a first axis that is fixed relative to the first housing; a first driven gear situated within the first pump cavity and rotatable about a second axis so as to mesh with the first driving gear and contrarotate about the second axis relative to the first driving gear whenever the first driving gear is rotating about the first axis; a first inlet allowing fluid to enter the first pump cavity so as to be propelled by the rotating first driving and driven gears through the first pump cavity; and a first outlet allowing fluid, propelled through the first pump cavity by the rotating meshed first driving and driven gears, to exit the first pump cavity; the second gear-pump chamber comprising a second housing defining a second pump cavity; a second driving gear situated within the second pump cavity and axially connected to the first driving gear so as to be rotatable about the first axis synchronously with the first driving gear; a second driven gear situated within the second pump cavity and rotatable about a third axis fixed relative to the second housing so as to mesh with the second driving gear and contrarotate relative to the second driving gear whenever the second driving gear is rotating about the first axis; a second inlet allowing fluid to enter the second pump cavity so as to be propelled by the meshed second driving and driven gears through the second pump cavity; and a second outlet allowing fluid, propelled through the second pump cavity by the rotating second driving and driven gears, to exit the second pump cavity; and the first and second pump cavities being interconnected by a fluid conduit coaxial with the first axis, the conduit allowing, whenever the first and second gear-pump chambers are pumping fluid so as to generate a higher pressure in the first pump cavity relative to the second pump cavity, fluid to pass from the first pump cavity to the second pump cavity so as to maintain hydraulic prime of both the first and second pump cavities; (e) a hydraulic circuit for conducting ink from the reservoir to the second inlet, from the second outlet to the printing head, from the gutter to the first inlet, and from the first outlet to the reservoir; and (f) a prime mover operably coupled to the pump head so as to cause rotation of the first driving gear about the first axis.