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US 7,461,465 B2Granted
Pressure control in centrifugal evaporators
AssigneeGenevac Limited
InventorRoger Lee-Smith
Life of this patent
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AssigneeGenevac Limited
InventorRoger Lee-Smith
Estimating the term…
A method of controlling the pressure within a chamber (12) of a drying apparatus (10) from which air and vapour is removed by a pump (30), which is operated continuously during the drying process. If both of a vent valve (18) and a pressure control valve (32) is opened, air at atmospheric pressure is drawn by the pump (30) directly from the pressure control valve (32), and via the chamber (12) and a non-return valve (26) from the vent valve (18). When the pressure in the chamber (12) is to be reduced both vent and pressure control valves (18, 32) are closed to allow the pump (30) to remove air, gas and vapor from the chamber (12) via the non-return valve (26). After a required chamber pressure has been reached, the pressure control valve (32) is opened while the vent valve (18) remains closed.
A method of operating a vacuum drying chamber having a vent valve, a non-return valve leading to a vacuum pump and a pressure control valve which communicates with the inlet to the pump, comprising the steps of:
A method of controlling the pressure within a chamber of a drying apparatus from which air and vapour is removed by a pump which is operated continuously during the drying process, wherein the chamber has a vent valve and a non-return valve is provided between it and the pump, and the pump has a pressure control value which communicates with an inlet thereof, comprising the steps of:
Vacuum drying apparatus comprising a drying chamber, control means for controlling the pressure within the chamber, a pump arranged to remove air, gas and vapour from the chamber, a vent valve which when open admits air to the chamber from outside the apparatus, a pressure control valve which when open admits air directly to the pump inlet from outside the apparatus, and a non-return valve between the chamber and the pump inlet, wherein the control means is arranged to close both vent and pressure control valves when the pressure in the chamber is to be reduced by the removal of air, gas and vapour from the chamber by the pump through the non-return valve, and to at least partly open the pressure control valve while keeping the vent valve closed when a given partial vacuum pressure is achieved in the chamber, whereby a high rate of air flow from the pressure control valve is maintainable the pump by continuous operation thereof during the drying process to clear the interior of the pump of solvent, while the chamber pressure remains substantially constant.
Dependencies are inferred from the claim text.