AMETEK Pacific Design Technologies designs passive thermostatic thermal control valves that automatically regulate coolant temperature in aerospace systems without any electrical power or external control circuitry. These valves ensure that liquid coolant maintains a defined set-point temperature, protecting sensitive equipment by keeping it within allowable temperature ranges.

A high-output thermal actuator inside each valve expands or contracts with fluid temperature, moving a sliding spool (or poppet) to open or close flow passages and precisely modulate coolant flow as needed. This self-contained regulation provides reliable and precise temperature control critical for spacecraft and aircraft thermal management.

PDT thermal control valves can be configured in either mixing or diverting arrangements, offering flexibility for aerospace thermal system designers.

In a mixing configuration, the valve blends fluid from a hot inlet and a cold inlet to achieve a desired outlet temperature. In a diverting setup, a single inlet flow is proportionally split between two outlets depending on fluid temperature.

This versatility allows engineers to tailor cooling loops for different scenarios, such as mixing warm and cool coolant streams to maintain stable thermal conditions, or bypassing a heat exchanger until the fluid reaches its target temperature.

The sealed paraffin wax actuator uses a wax-based phase-change material that expands when heated and is a popular choice for aviation applications and other moderate-duration platforms. Elastomer seals can be selected for compatibility with common aerospace coolants or oils.

This design covers nominal control temperatures from approximately 35 °F to 210 °F (2 °C to 98 °C) with a typical control band of ± 8 °F (± 5 °C) around the set-point, making it well suited for aircraft thermal management systems that must cope with both low ambient temperatures at altitude and high heat loads during operation.

For critical long-duration spacecraft and satellite applications, PDT provides an all-metal bellows actuator design with no organic seals. A sealed metallic bellows filled with a high-expansion fluid replaces the paraffin wax, and the all-welded construction delivers maximum reliability and zero leakage over long missions.