PRT® - Military-Grade Heat Shrink
1 year ago
Heat shrinkable tubing has been used for years in both commercial and military applications to bundle and jacket electrical wiring.
The tubing’s unique ability to change dimensions when heated provides an excellent means of creating a high performance secondary jacket that provides additional chemical, electrical, mechanical and thermal protection in addition to circuit identification. However, classic heat shrink tubing has several installation-related limitations. The tubing requires the installer to fish the wiring through the tubing prior to heat recovery. The issue is of minor consequence at the wire board fabrication level where wire end access is easy. However, the “fishing through” process becomes time consuming and labor intensive when in-service wires or cables require repair. Typical wire harnesses have large electrical connectors and mounting clamp hardware that limit repair access. A wire bundle requiring repair between cable breakout branches presents an even bigger repair challenge. All these issues hamper installation of conventional shrink tubing as a repair medium.
Historically, repair problems have been addressed with the use of special high expansion ratio shrink tubing which is typically four to six times the diameter of the cable in its expanded state. The problem is that these high ratio tubing’s may not be readily available, have a limited size range, yield a very thick and stiff cable repair and ultimately may not be large enough to accommodate the end connector size. Even high expansion ratio tubing’s cannot solve repair problems that occur between cable branch breakouts and a cable that passes through a bulkhead.
Because of these limitations cable repair problems have typically followed more installation friendly methods. Solutions such as using adhesive backed or self-vulcanizing tape wraps, loose fitting side entry jackets, liquid sealants, bulky pre-molded splice kits, spiral cut tubing and combinations of the above. Although these methods minimize disassembly and labor time, they do so at the expense of cable reliability, longevity and performance.
Zippertubing’s PRT Tubing is the solution.
PRT was specifically developed to provide an easy and economical solution to these repair problems! PRT tubing is a side entry, wrap-a-round, heat shrinkable tubing that combines the same high performance characteristics of solid heat shrinkable tubing with the installation ease and time savings associated with an electrical tape wrap. It eliminates 99% of the electrical harness disassembly problems classically associated with a shrink tubing repair by eliminating the need to slide the tubing over the end of the wire. A PRT repaired cable provides performance and longevity comparable to standard shrink tubing.
The PRT product line offers repair of wire and cable sizes ranging from .070” to 1-7/8”. It is offered in several different configurations. Standard PRT is used for adding additional abrasion protection, PRT-ES includes a hot melt adhesive liner for creating environmentally sealed installations, PRT-S includes an EMI shield cloth layer for adding EMI hardening to wires and cables and PRT-1553 kits include EMI shielding cloth in tape form and the PRT-ES material to create an environmentally sealed Shielded Cable repair kit.
A typical PRT Tubing repair takes only a few minutes to complete and yields a repair that is as rugged as the original cable jacket. It offers system performance of -55 to 135C operating temperature, very good fluid resistant and a life span of many years. After extensive testing by the U.S. Navy, PRT is listed as a standard repair item and method in NAVAIR’s 01-1A-505 repair practice manual for aircraft electrical wiring system. This Navy repair procedures is accepted standard practice for all US and NATO airborne services. PRT is covered by several National Stock Numbers (NSN’s) for use by all U.S. military and governments services.