User`s manual

22 Chapter 3: Theory of Operation
Calorimetry Sciences Corp.
CSC 5300 N-ITC III 23
User’s Manual
Chapter Four: Hardware Description
Description of Parts and Functions
The CSC Model 5300 N-ITC III consists of the measuring unit (calorimeter block and
two non-removable reaction vessels), the burette assembly, which includes the stirring
system, and a cleaning accessory. With the exception of the power on/off switch located
on the back of the calorimeter unit, all functions of the N-ITC III are controlled remotely
by the computer through the USB connection. For more information see Chapter Five:
Software Description.
Measuring Unit
The measuring unit includes the calorimeter block and two non-removable reaction ves-
sels (sample and reference cells). Access tubes extend downward from inside the burette
mounting cavity on the top of the calorimeter and serve as conduits for the lling syringe,
titrant delivery, and reference needle.
They also provide for titrant equilibra-
tion and as a thermal barrier to the en-
vironment outside the calorimeter.
The CSC Model 5300 N-ITC III uses
a differential power compensation
design for maximum sensitivity and
responsiveness. Semiconducting ther-
moelectric devices (TED) are used for
temperature control as well as to detect
temperature differences between the
sample and reference cells. A computer
controlled PID loop uses a control
heater on the sample cell to maintain
a zero temperature difference between
the sample and reference cells (see
∆T
Sample
Cell
Reference
Cell
Thermal
Shield
TED Controlled
Block
Control
Heater
Figure 4-1: The N-ITC III measuring unit.