Transitiometry
Technical data


Scanning Transitiometers from BGR TECH

GENERAL TECHNICAL DATA

Pressure range:  0.1 - 400* MPa (extension to 700 MPa is possible)
Temperature range: 253** K - 673 K
Initial sample volume: 0.3 ml - 5.0 ml (depending on the pressure range)
Isothermal pressure scanning rate: 2 kPa s-1- 0.2 MPa s-1
Isobaric pressure compensation rate: 2 kPa s-1- 0.2 MPa s-1
Isobaric or isochoric temperature scanning rate:0.5 mK s-1-5 mK s-1
Resolution in isothermal volume scanning: 5*** nl
Resolution in isobaric volume change recording: 5*** μl
Precision of temperature control/programming: ≈ 10-4 K
Accuracy of pressure measurements: 0.15 % fsd
Thermal resolution: 10-6 W (higher is possible) 

* Pressure range (-es) can be selected
** built-in coolers for manual liquid and compressed air cooling are supplied without any cold source; incorporation of an external cold source with an automatic cooling control integrated with the main software can be further negotiated
***the volume of the pressure pump can be selected from 9 cm3 to 250 cm3 depending on the pressure range.


FUNCTIONS
Basic
Isothermal simultaneous pressure scanning measurements  of αp and κT or (after integration) of and   of either liquid or/and solid samples;
Isobaric simultaneous temperature scanning measurements of ∆H  and ∆V   for various transitions.

Optional (after proper calibrations)
Isothermal simultaneous volume scanning measurements of β and κT or (after integration) of and ∆V  of either solid or/and liquid samples;
Isochoric simultaneous temperature scanning measurements of ∆U  and ∆p  for various transitions.

PERFORMANCE
The transitiometers perform as virtual instruments (VI) created with LabView graphical programming language. The communication with particular elements of the instrument is done through a cable connector block and a PCI/MIO board with E Series architecture. During an experiment the operator can see on the screen the course and the actual state of four variables: temperature, pressure, volume change and the thermal power of the process under investigation as as well as the functioning of the digital control loops.

APPLICATIONS
Scanning transitiometers can be used in many fields of science and industry where the wide temperature and pressure ranges as well as the high measurement sensitivities of both mechanical and thermal properties are important for the investigations performed. The standard experimental vessels are adapted to situations where the investigated substance is immersed in the hydraulic fluid (mercury, water or any other liquid or a supercritical fluid). The vessels can be conveniently opened and closed with the help of a torque wrench and a special stand to hold them in place. Such a procedure facilitates filling of the vessels and ensures their long life and reproducible use even at very high pressure. Protective ampoules for the investigated substances made from a soft substance to transmit pressure can be negotiated and supplied as additional accessories. All the internal parts of the transitiometer being in contact with the media under investigation are from stainless steel. Other anti-corrosive materials such as  hastelloy C22 can be negotiated. The calorimetric unit has also an upper access (see the schematics) which permits to use special reaction vessels with stirring and/or dosing solvents or reactants. Such vessels perform up to 50 MPa (higher pressures can be negotiated) and can also accommodate analytical or structural detectors, such as spectro-probes. In such a case a special spectro-transitiometric software is supplied which permits to observe and record simultaneously also spectrometric information.