Patent ID: 7749053

Claim:
A device for generating a negative pressure in a sealed chamber of a tablet press and/or a tablet isolator, comprising: a motor-driven fan connected to the sealed chamber through a first conduit to extract air from the sealed chamber; an inlet for the sealed chamber; a first valve ( 20 ) in the inlet having a control input which is connected to a control unit; a pressure sensor within the sealed chamber connected to the control unit; a second conduit connected to a pressure source through a second valve ( 38 a ) which has a control input connected to the control unit; a third valve ( 32 ) in the first conduit, the third valve having a control input connected to the second conduit; an ejector pump with an intake connected to the sealed chamber through a fourth valve ( 28 ), and the fourth valve having a control input connected to the second conduit, the elector pump having a driving inlet connected to the second conduit, the device working such that if the pressure sensor senses a negative pressure above a predetermined negative value the control unit closes the first valve and opens the second valve so that by pressure in the second conduit the third valve is closed and the fourth valve is opened and the ejector pump can evacuate the sealed chamber.