Temperature Sensing; Temperature Control System; Overspeed System - Beckman Coulter Optima LE-80K Instruction Manual

Description

TEMPERATURE SENSING

TEMPERATURE CONTROL SYSTEM

OVERSPEED SYSTEM

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Trademark of E. I. Du Pont de Nemours & Company.
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Rotor temperature is monitored by a radiometer mounted in the
bottom of the rotor chamber (see Figure 1-2) when the chamber pres-
sure is below 100 microns. Above 100 microns (or if the radiometer
fails), chamber temperature is measured by a thermistor mounted in
the chamber.
The instrument uses a solid-state thermoelectric refrigeration and
heating system, which eliminates the need for a conventional refriger-
ation system and heater. Neither Freon
coolant required is forced air from the cooling fans.
After the power is turned on, the temperature control system is acti-
vated when the door is closed and the vacuum system is turned on.
The rotor temperature is controlled to ±1°C of the set value. If the
temperature system malfunctions, the TEMP diagnostic message will
appear and the rotor will decelerate to a stop.
The overspeed system is a safety feature designed to ensure that the
rotor does not exceed its maximum allowable speed. This system
includes photoelectric sensors in the rotor chamber next to the drive
spindle (see Figure 1-2) and an overspeed disk on the bottom of the
rotor. Individual rotor manuals provide information on the correct
overspeed disks to be used with each rotor.
The overspeed disk has alternating light and dark sectors. As the rotor
spins, the passage of reflecting and nonreflecting sectors over the pho-
toelectric device generates a series of pulses that are detected by elec-
tronic circuitry and processed by the software.
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