8 of 40
Operating Manual:
SU
105
UE
SU105U-MAN10-C
|
02.06.19
2. Features of the SU105UE freezer
2.1 – Free-Piston Stirling Engine
The SU105UE Ultra-Low Temperature Freezer uses the state of the art Stirling
Ultracold Model M150A free-piston Stirling engine to provide high efficiency,
deep-temperature cooling. No HCFC or CFC refrigerants are used in the M150A and
SU105UE. The M150A Stirling cycle engine uses approximately 2 grams of helium
gas as a working fluid. 30-33 grams of R-170 are used in the thermosiphon which
removes energy from the freezer.
2.2 – Cabinet Design Features
The cabinet is VIP insulated with polyurethane foam support providing an internal
volume of cabinet approximately 105 liters. The environmentally friendly, SNAP-
compliant blowing agent is Ecomate®. A locking cam door latch ensures door
gasket compression when closed. Door sealing consists of three gaskets and is
factory replaceable. A door defrost minimizes water or ice deposition on the gasket
interface.
2.3 – Temperature Monitoring Features
Two resistance temperature detectors (RTDs) measure the internal cabinet
temperature of the SU105UE. One provides input to the free-piston Stirling engine
controller and the other provides input for the Graphical User Interface (GUI) display
and for reporting and logging. The display RTD may be user calibrated through the
GUI. The GUI provides a door open timeout alarm and monitors the temperature
reporting RTD for excursions beyond high and low limits that are set automatically
or manually. Alarms are reported through an audible alarm in the freezer enclosure
and through a contact closure that may be connected to an external alarm. The GUI
provides options to temporarily suppress alarms and set a delay time before the
alarm is reported via the contact closure. A one-time temperature alarm suppression
provided by the software allows for the initial cooling of the freezer after start-up.