Thermal protection is a subject that most cable design professionals do not encounter very often. Knowing how to approach the problem and applying the correct material solutions can mean the difference between system success and failure.
In classic electrical interconnect wire harness’ fluid exposure and mechanical abrasion, problems tend to be systemwide and require that the entire cable assembly be protected. However, most thermal exposure problems tend to be localized and generally can be handled by a localized solution. Applying the system wide approach to thermal protection generally adds tremendous cost while providing minimal performance to the overall system.
It is critical for the cable designer to clearly define the thermal problem location, the amount of heat exposure and the heat exposure dwell time. These variables will define the type of thermal protection material required and its design and location. Most heat reflect materials operate by radiating 80-90% of the thermal shock back into the environment rather than trying to totally insulate the substrate materials from the thermal source. Also, it is a rare situation where the components to be protected are not separated from the heat source by some distance. Air gap separation is a tremendous thermal insulator in itself. This allows most “heat-reflect” material to be relatively thin, flexible and cost effective. True thermal insulator blankets tend to be quite thick, have minimal flex capabilities, are easily damaged and very expensive. Fortunately, most heat protection applications do not require the thermal blanket approach.
Consider the following application scenario which is quite typical. A 50’ long welding cable is exposed to 250°C thermal exposure and welding splatter. Designing the entire cable from materials capable of handling this environment is the wrong approach. In reality, it is most likely that only last six to ten feet of cable will be exposed to the weld splatter problem and only the last two or three feet near the welding head will see the extreme heat exposure. One must also consider if the welding head is in continuous operation (hours) or only for short periods (minutes) followed by short periods of non-operation. Also how much air space is between the cable and the actual heat source? All these factors need to be considered in developing a cost effective solution that meets the performance demands.
Zippertubing's HeatReflect® Materials are the solution.
Zippertubing offers a variety of light and medium weight Heat Reflect materials providing thermal performance from 149°C to 650°C. These materials can be configured for round and flat cable protection as well as converted into highly specific customer designs. Zippertubing can mix and match these materials with high temperature closure systems including Aramid and Nomex® Hook & Loop, Aramid mechanical zippers, Stainless Steel snap buttons, Aramid/Steel sewing threads as well as incorporate and protective internal and external flaps. In addition, Zippertubing offers its unique “Insuflect-650” product for specialized thermal blanket applications operating at temperatures up to 650°C. Zippertubing “Heat-Reflect” materials and designs are currently used over a broad selection of industries including Automotive/Trucking, Military/Commercial Aerospace, Missiles/Launch Tower Hardware and Spacecraft components. So, if you have thermal exposure problems contact a Zippertubing Application Engineer today and let us help you create a viable solution.