Freeze drying methods employing vapor flow monitoring and/or vacuum pressure control - Patent Articles

United States Patent 6,226,887
Tenedini , et al. May 8, 2001
Freeze drying methods employing vapor flow monitoring and/or vacuum pressure control
Abstract
Freeze drying apparatus and associated lyophilization procedures are provided employing vapor flow detection and/or vacuum control for monitoring and control of the lyophilization process. The vapor flow detector, such as a windmill sensor, is disposed to monitor vapor flow from product undergoing lyophilization. In a batch process, vapor flow is collectively monitored with the vapor flow detector between the process chamber and condenser chamber, while in a manifold configuration separate vapor flow detectors are employed at each flask attachment port. A windmill sensor provides visual feedback to an operator and/or electronic feedback to a system controller. A vacuum control system is also provided for use with or independent of vapor flow detection. This vacuum control disconnects the vacuum source from the process chamber when pressure within the process chamber falls below a first predefined set point. The vacuum source is then reconnected if process chamber pressure rises above a second predefined set point.
Inventors: Tenedini; Kenneth J. (New Paltz, NY); Bart, Jr.; Siegfried G. (New Paltz, NY)
Assignee: S.P. Industries, Inc., The Virtis division (Gardiner, NY)
Appl. No.: 465650
Filed: December 16, 1999
Current U.S. Class: 34/287; 34/292; 34/293; 34/403; 34/407
Intern'l Class: F26B 005/06; 570; 571; 92; 286
Field of Search: 34/284,287,292,402,403,406,437,439,192,237,293,297,407,558,559,565,566,567