Pressure and Temperature Probe for Studies of Biological Materials

In our previous paper 1] a high pressure technique for monitoring pressure up to 700 MPa and temperature from m 40 °C to +100 °C in several pressure vessels simultaneously was reported. This technique, applied in Unipress High Pressure Multivessel Apparatus for studies of biological materials, revealed some limitations. In this paper we propose a new solution which allows to overcome them. In this solution two different pressure media are used, separated from each other: one suitable for biological studies and the other proper for electric sensors. A new integrated pressure/temperature probe is presented in which manganin pressure gauge is confined in a metal bellows separating the two pressure transmitting media. The bellows can be easily assembled or disassembled, allowing promptly to refill pressure medium or to replace the pressure gauge. Temperature is measured by constantan/copper thermocouple. The probe is linked to data acquisition system. Taking into account temperature dependence of the manganin pressure gauge, simultaneous measurements of the resistance of pressure gauge and thermocouple voltage allow to compute pressure at any temperature. The new probe is integrated with the bottom closure of the pressure vessel which also incorporates capillary inlet. Such a design leaves free access from the top of the vessel, allowing easy mounting the studied samples as well as other additional probes.