Heat Switches

Active and passive heat switches

Our heat switches support rapid cool-down and thermal isolation, with standard and bespoke designs. Active models are controlled by the user; passive models switch automatically as temperatures change.

Active Heat Switches

In an active heat switch a small external gas absorber pod is connected by a gas tube to the foot of the switch. Gas is released into the switch by electrically heating the pod under user control. The thermal conductance in ON and OFF states depend on material properties of the gas and the heat switch shell, and on the temperatures at the ‘hot’ and ‘cold’ ends.

An ideal heat switch would have high on-state conductance and very low off-state conductance. In practice it is very challenging to manufacture a gas-gap heat switch that meets both criteria. The space available to accommodate the heat switch is an additional constraint.

To find out whether we can provide a heat switch for your particular requirements, use our Heat Switch Questionnaire to let us know more about your intended application.

Heat Switch Questionnaire

View Gallery

Passive Heat Switches

A passive switch has an internal absorber and operates automatically; it turns ON and remains fully ON while the hot end temperature is greater than around 15-20K. In the ON state the thermal conductivity is large (around 100mW/K at 4K). When the hot end temperature drops below around 10K the switch will start to turn OFF though it will not be fully OFF until the hot end temperature is ~4K. When the switch is OFF it has a residual thermal conductance dictated by the material properties and dimensions of the shell.

To find out whether we can provide a heat switch for your particular requirements, use our Heat Switch Questionnaire to let us know more about your intended application.

Heat Switch Questionnaire

View Gallery

Quick Enquiry

Quick Enquiry