METHODS FOR MEASURING PRESSURE IN FREEZE DRYING SYSTEMS
An improved method for determining pressure in a lyophilisation system containing a lyophilisation chamber and a condenser chamber wherein a freeze drying operation is being performed is provided for. The improved method uses a temperature measuring device such as a thermocouple or a temperature resistance device to measure temperature and from this measurement the pressure of the components in the lyophilisation chamber can be calculated using a predetermined relationship between temperature and pressure.
1 . An improved method for determining pressure in a lyophilisation system wherein a freeze drying operation is being performed, the improvement comprising measuring temperature in the lyophilisation system and calculating pressure of the lyophilisation system therefrom using a predetermined relationship between temperature and pressure.
2 . The method as claimed in claim 1 wherein the lyophilisation system comprises a lyophilisation chamber and a condenser chamber.
3 . The method as claimed in claim 1 wherein the temperature is measured with a device selected from the group consisting of a thermocouple and a resistance temperature device.
4 . The method as claimed in claim 1 wherein the pressure is calculated from the temperature according to the formula:
5 . The method as claimed in claim 1 wherein water, nitrogen and air are present in the lyophilisation system.
6 . The method as claimed in claim 2 wherein the condenser chamber contains a condenser coil.
7 . The method as claimed in claim 2 wherein the condenser chamber is in fluid communication with a vacuum pump.
8 . An improved freeze drying method in a lyophilisation system, the improvement comprising measuring temperature in the lyophilisation system and calculating pressure of the lyophilisation system therefrom.
9 . The method as claimed in claim 8 wherein the lyophilisation system comprises a lyophilisation chamber and a condenser chamber.
10 . The method as claimed in claim 8 wherein the temperature is measured with a device selected from the group consisting of a thermocouple and a resistance temperature device.
11 . The method as claimed in claim 8 wherein the pressure is calculated from the temperature according to the formula:
12 . The method as claimed in claim 8 wherein water, nitrogen and air are present in the lyophilisation system.
13 . The method as claimed in claim 9 wherein the condenser chamber contains a condenser coil.
14 . The method as claimed in claim 9 wherein the condenser chamber is in fluid communication with a vacuum pump.