Our thermal actuators contain our exclusive Thermoloid® material, sealed in the actuator, which changes phase from a solid to a liquid as the temperature increases. As the phase change occurs, the volume of the Thermoloid® material changes significantly, with the liquid volume greater than the solid volume. Since the material is essentially incompressible and encased in a rigid housing, only the piston can move and extend as the volume of the material increases. This motion can be used to operate a wide variety of devices. When the Thermoloid® material cools the volume contracts and allows the piston to retract if a return force is acting on the piston. The piston will not normally retract unless a return force is present.
The phase change and resultant motion occurs over a narrow temperature range. This property allows precise control of a device at a specific temperature with no significant effect outside the chosen control range.
The precise motion of these thermal actuators can be used to operate a wide variety of devices, limited only by the imagination of the designer. Temperature actuated valves, switches, latches, clamps and control devices are typical applications.
The high heats of fusion and heat capacities of the Thermoloid® material make it an excellent candidate for heat sink applications.
No outside power source is required to produce motion. Temperature change alone can be used to operate a device; eg.: open or close a valve, move or release a latch, operate a switch. Because the Thermoloid® material operates in both the solid and liquid phase, each of which are essentially incompressible, load changes on the piston (within design limits) have little or no effect on operating temperature. This is in contrast to vapor-filled or liquid to vapor phase change devices, which are generally very sensitive to load changes (changing the load on these devices, eg., changing spring tension, is used to change the operating temperature range).
Since the operating temperature of solid-liquid phase change actuators is determined by the Thermoloid® material properties (ie, melting and solidification temperatures), the operating temperature is extremely stable, repeatable, and accurate. The properties of these thermostatic materials are so precise that they are used as primary reference standards by ASTM for instrument calibration. An analogy is the freezing temperature of water at 32°F when water changes from liquid to solid: stable, repeatable, and accurate enough for use as a temperature calibration standard (ie. ice point reference).
- Can be made from most machinable materials
- Long, powerful stroke
- Rugged and compact
- Reliable and reproducible
- Wide choice of temperature ranges
- Not effected by shock or vibration
- Can be used in pressure or vacuum, liquid or gas
- Custom mounting configurations available
- Typical temperature change for maximum stroke: 10F° to 20F°(5.5C° to 11.1C°)
- Start to stroke temperatures from about 15°F to 300°F (-9.4°C to 149°C) or higher