CPI’s X1 thermal switch is being increasingly used by both American and European avionics manufacturers and integrators as their thermal switch of choice for spot detection of overtemperature conditions in systems throughout the aircraft. Recent integrations include FAA approval as a Fenwal replacement on Gulfstream jets, use in the De Havilland “Twin Otter” aircraft, and use by specialty aircraft manufacturer Diamond Aircraft in Europe to name a few of the most recent.
But actually, CPI’s thermal switches have been flying around the world in commercial aircraft for decades. The recent uptick in design-ins may have something to do with manufacturers realizing that in addition to superior thermal performance, vibration resistance, and electro-mechanical endurance, our switches are just a whole lot less expensive than Fenwal, and other solutions commonly used.
Thermal Switch Uses in Modern Aircraft
All modern aircraft employ a number of thermal sensing elements for aircraft systems. So called Spot Fire Detection Systems refer to systems where overheat conditions are monitored at a specific point in a compartment or LRU bay. In order to receive FAA approval, these systems must demonstrate superior detection performance and have the proven ruggedness to survive in the harsh thermal and vibrational environment of modern aircraft.
Typical zones on aircraft that employ spot fire detection include:
- Auxiliary power unit (APU)
- Engine compartments
- Cargo and baggage compartments
- Lavatories on transport aircraft
- Electronic bays
- Wheel wells
Several detectors, or sensing devices, are available to solve these detection challenges, encompassing a number of different technologies. Many modern aircraft have some type of thermal switch system or thermocouple system. A thermal switch system has one or more indicator lights or audible alarms that trip when a thermal limit is reached.
They are sometimes connected in parallel with each other but in series with the indicator lights. If the temperature rises above a set value in any one section of the circuit, the thermal switch closes, completing the light circuit to indicate a fire or overheat condition. No set number of thermal switches is required; the exact number is usually determined by the aircraft manufacturer. On some installations, all the thermal detectors are connected to one light; on others, there may be one thermal switch for each indicator light.
CPI Rod & Tube Series Thermal Switches for Avionics Applications
Recently CPI thermal switches like our X1 have seen increasing use as replacements for other thermals owing to their extreme mechanical endurance, setpoint precision, and much lower unit cost making them extremely good choices in spares and retrofit applications. In a recent retrofit application undertaken for a Gulfstream, the CPI X1 thermal switch was qualified to replace the equivalent Fenwal Switch for almost half the cost. The CPI X1 Thermal Switch has 100% equivalent functionality and accuracy with arguably superior electromechanical endurance.
CPI’s X1 Series thermal can maintain a setpoint anywhere from 0 to 850F, with a +/- 5F tolerance standard. Tighter tolerances are available. CPI thermal switches are made entirely in the USA at our manufacturing facility in East Hanover New Jersey.
| FEATURES | TECHNICAL SPECS | APPROVALS/CERTIFICATIONS |
| · Factory Adjustable Set Point | Temperature Range 0F -850F (-17C to 454C) |
FAA, IPV-67, MIL-S-24236 |
| · Highly Vibration Resistant | Response time max 5s | |
| · Stainless-steel and inconel construction | Different Probe lengths from 2.25” to 5.00” | |
| · Rapid Response Time and high tolerance versions available | Available in close-on-fall, open-on-fall, close-on-rise, open-on-rise configurations |
Consider CPI Thermal Switches for your Next Spares Order
It makes good economic sense to consider CPI thermal switches for your next retrofit program, or as a design-in when your current thermals are too scarce or too expensive, or both! CPI’s USA made thermal switches are readily available through distribution, or directly from the factory for special configurations.
For more information, Contact your CPI Solutions team today.
Original content posted on https://www.cpi-nj.com/blog/aircraft-fire-detection-spot-fire-detection-systems/
According to sources with combat experience, the RPG is most typically a “100-yard weapon”. Adversaries know that to be effective, the RPG needs to be fired at close range. The RPG-7’s maximum flight velocity is around 300 meters per second, so assuming roughly 100 yards to target, it could take as little as 300 milliseconds from launch to impact. Given that any (aimed) active defensive system must detect the inbound threat, classify it, process a response, and aim and launch the countermeasure before the threat makes contact; a realistic system design goal would require the aiming mechanism to be capable of addressing a threat from any direction in 100 milliseconds or less. There is presently no traditional “gun and gimbal” turret system that can aim this rapidly.
For RPG defense, a continuously-rotating countermeasure aiming and launching system provides a much faster response than a traditional “gun and gimbal” turret system. Many active RPG countermeasures are self-propelled munitions. They do not require robust gun barrels for launch. They may be launched from short tubes that are little more than storage capsules. Self-propelled munitions also do not produce significant recoil. We propose a design of a fast aiming-and-launch system in the form of a rotating drum. This drum-shaped countermeasure launch container houses multiple munitions, each in a short launch tube, in an outwardly-facing circular array. The circular array lies on a plane perpendicular to the drum’s axis. Given that the launch tube is only about as long as the munition itself, this circular array could be realized in a drum-shaped launcher whose overall diameter is slightly larger than twice the length of an individual countermeasure round. Rotating the drum about its axis creates a situation in which any point, or multiple points, on a planar azimuth of rotation are continuously brought into the line of fire of the munitions in the array. Any point within a full 360 degrees can be targeted in the time that it takes to rotate the nearest-available munition (array element) to that point. In one example, 8 countermeasure munitions are arranged in the outward-facing 360 degree circular array with munitions spaced equally every 45 degrees. In this example the drum must rotate (at most) 45 degrees in order to bring the nearest munition to any point around a 360-degree azimuth. Depending upon the rotational speed of the drum, the time required to bring munitions to bear could be on the order of milliseconds. The preceding description provides a rotational turret capable of firing 8 countermeasures. However a drum-shaped launcher suggests the possibility of superposing (stacking) multiple arrays of countermeasures. So a single drum-type launcher is capable of firing 16 or more defensive munitions prior to reloading and would not potentially require a second instantiation of the turret for multiple threat detection.
Further calculations on a drum that rotates about as fast as a ceiling fan (300 RPM), show that a countermeasure could be delivered to any point on the azimuth in 25 milliseconds or less. This is roughly the amount of time that it takes an RPG to cover about 7 meters.
side of the vehicle. Meant to be operated by men with gloved hands, the switches selected allow operators in the rear to signal the driver in the cab when ready to move, or allow the operators to manually advance the compression throttle as a safety feature prior to moving the vehicle.
Control products makes a complete line of waterproof pendant switches which are specifically designed for the needs of high reliability, high endurance, and complete watertight operation. Couple these with our versatile mounting brackets and what you have is a pendant switch with up to 15A capability that will be ready to work when you need it, no matter what it is exposed to in the interim.
closure pendant, also completely sealed in Neoprene and immune to moisture and vibration. Common uses include as a welding torch switch or for motor “jogging” applications.
In this application our K1005-504 is mounted near the wheel well where it can be subject to a fair amount of heat and vibration between uses. Our Neoprene seal extends the temperature range from -65F to 185F and completely seals the switch away from dust, moisture and vibration as well.
In this application the same K1005-504 is used as a control on the Up-Front-Display Unit inside the vehicle.
machine exposed to extremes of water, dirt, dust and other airborne particulates. A Robustly sealed and washdown proof switch is of extreme importance to these folks.
refining and selling for over 70 years. They are implemented in a style commonly referred to as “pendant switches” owing to their size and form factor. What CPI does is to pair one of our sealed, waterproof pendant switch designs, with an actuator mounting bracket which can allow the switch to be used in an almost infinite number of applications. Some customer even use the switch without any bracket for a manual operator driven application such as a toggle switch on a motorboat winch.
on industrial sand blasters, and in one case as a customization to a Mountain bike used for enduro-racing (See our post on 
Control Products, INC 