THERMAL CONTROL

STATIC OPERATION

•  In normal operation the controller uses a PID algorithm to adjust heating power and cooling pumping flow to maintain the current temperature


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RAMP OPERATION

•  To ramp to a user-defined target temperature TT at a specified ramp rate R from a current temperature TC, the controller calculates a target temperature profile

•  The controller then adjusts the heating power and cooling pumping flow to achieve the target temperature profile


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•  In a real system, the wiring, a sample on the heating block, and the surrounding atmosphere are thermal loads that dissipate power

•  Electrical and thermal inertia can result in short time delays in electrical and thermal responses and in achieving stability in the target temperature


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•  Faster ramp rates can result in greater overshooting of target temperatures because of thermal inertia

•  Overshoot and delay can never be eliminated fully in a real system, but can be minimized by using the slowest ramp rate possible for the process


SAMPLE COOLING

•  To achieve below ambient temperatures an active cooling system is necessary: a recirculating water chiller or a liquid nitrogen cooling system

•  Active cooling has the advantage over passive cooling to allow fast experiment cycling


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FRAME COOLING SYSTEMS

•  Frame cooling option with recirculating chiller allows thermal control of frame independent of sample thermal block

•  Keeps frame safe to touch and prevents frost buildup on windows


LIQUID NITROGEN COOLING SYSTEMS

•  Liquid nitrogen systems provide sample cooling to as low as -190°C depending on pump power and thermal block size

•  Systems consist of a pump, a Dewar, a lid with a stoppered port for refilling during operation, and connecting tubing

•  Three liquid nitrogen pump output options available, LN2-P2, LN2-P4, and LN2-P8, which suction liquid nitrogen through the equipment and are controlled by the mK2000

•  Three Dewar sizes, 2 L, 10 L, and 30 L, with easy refillable lid options to control liquid nitrogen supply to instruments

•  Integrates with mK2000 PID controller with ±0.1% resolution


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LIQUID NITROGEN SYSTEM MINIMUM TEMPERATURES

 

LN2-P2

LN2-P4

LN2-P8

STAGES

HCS302/302G/402/412W

-100°C

-190°C

-190°C

HCS321Gi

-60°C

-70°C

-80°C

HCS621G/421V

-160°C

-190°C

-190°C

HCS622G/422V

-100°C

-190°C

-190°C

FS1

NA

-60°C

-190°C

CLM77K/CLM77Ki

NA

-190°C

-190°C

CHUCKS & PLATES

100mm square or round

-40°C

-60°C

-120°C

150mm square or round

-20°C

-40°C

-100°C

200mm square or round

NA

-30°C

-80°C

300mm square or round

NA

-20°C

-60°C

HCC602

-120°C

-170°C

-190°C

 

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