Fire and Ice

 

For many of us the idea of fire and ice might conjure up memories of the first book in Game of Thrones. Throughout that tortured story, “winter is coming,” but the forces of dragon fire threaten to keep it at bay, mostly.

Still, the idea of using “fire” to combat ice, isn’t very new. And its actually a short trip from fire breathing dragons flying around, to the idea of using thermal switches to control hot engine bleed air to de-ice a plane wing, right? Practically the same thing!

The bleed air application for CPI Thermal Switches.

While CPI has recently been engaged in bleed air applications for de-icing various commercial and military aircraft, the bleed air type application is even more general than that. In any application requiring reliable high-temperature sensing that redirects or provides airflow, CPI thermals are often selected.  Here’s just a few bleed-air applications that use our thermals.

1. On some naval ships CPI thermals are used to enable heating for electronics when it threatens to get too cold. These applications can involve bleeding hot air into a compartment or simply activating self contained heating elements.  In one application, Our AC006-501 will trigger when ambient temperature in the electronics bay drops below 70F, switching almost 10 Amps of resistive current directly for heating. 
2. ECS Bleed Air – In commercial aircraft, the ECS (environmental control system) uses our switch to bleed air in case the primary temperature sensors fail. Our X series thermal switches are located after the bleed air valve. If all should fail, the temperature can exceed the 500F rating of the aluminum heat-exchanger further downstream. In this application our switch prevents a shutdown of the cabin HVAC system.
3. Work Truck Bleed Air Solution – Sometimes the temperature of the payload in a work truck has to be carefully controlled. One way to do this is to bleed hot air from the engine into a closed compartment that keeps the payload in a certain temperature range.  For instance in DPW Salt trucks, freezing will prevent proper dispensing of road salt/sand so hot engine air is used to heat it. If the engine goes into regen mode however, it can exceed 650 degrees and the flow of air is too hot and must be redirected. In this case, a thermal switch must close and activate a flapper that closes in the exhaust pipe, directing exhaust from the engine out the top of the stack.
4. Aircraft Wing De-Icing – Our most common aerospace designs have been qualified per RTCA DO-160C and MIL-STD-810 and feature either our AD surface mount thermals (up to 300 F) or more commonly our M1 thermal switch (750F). Our switches are one of the few in the world that can be mounted directly on the cowel of the engine. We are often used here as well because our standard switch can withstand 20G of force. 

Key to the use of CPI switches in these applications is their high temperature capability and flexible mounting configurations. 

Snapstat Thermal Switches (0-300F) Surface mount options, low profile, can be mounted on engine block or other surfaces easily. Extremely resistent to shock and vibration, long life.

Plugstat Thermal Switches (0-650F) Tight tolerances and a small differential set these bimetallic thermals apart. They are slow make-break devices and come with a hermetically sealed option.

Rod & Tube Thermal Switches (0 – 1750F) – For your highest temperature thermal switch requirements, used over galley stoves, in fuel cells and APU’s for thermal runaway detection among other applications.

For more information about how CPI Thermal Switches solve problems of fire and ice, call our team today!