As fiber optics has increased in industry, so have the number of “deployable” systems applied to mining, oil and gas exploration and process industries.
As opposed to fixed installations, deployable systems are quickly installed, retracted and then relocated in the field. Some are found deep underground in some of the most inhospitable environments on earth. For this reason, industrial-grade fiber optics are typically commercialized versions of field-tested, proven military-grade products.
As such, components may have to withstand dust and debris, chemical exposure, temperature extremes, UV radiation, electrical power transients, interference, fire, moisture, humidity, water, crush, tension, flexing, impact and vibration.
Rick Hobbs, director of business development at Optical Cable Corp. (OCC), says when deploying a fiber-optic system, look at in its entirety. Unlike fixed applications, a deployable system should be a plug-and-play complete solution. OCC makes fiber-optic cable, connectors and assembly solutions for harsh and rugged environments.
According to Hobbs, primary elements include hardened cable jacketing; “genderless” connectors for quick deployment without regard for male or female ends; hybrid systems that include copper along with fiber to deliver data communications and power; and reel systems that speed deployment and retraction while protecting the fiber while not in use, or during transit.
OCC recommends using its tight-bound, tight-buffered distribution-style cabling, good for its small diameter and lightweight construction.
Distribution-style cable has a tight-bound outer jacket, which is pressure extruded directly over the cable’s core. Combining a helically stranded core and a pressure-extruded outer jacket provides an overall cable construction that offers better crush and impact protection and increased tensile strength. This also reduces outer jacket buckling during deployment.
Escalating degrees of cable protection are available as needed to meet the specific needs of an application.
Various jacket materials are available, including PVC or polyurethanes, tailored to meet the mechanical and environmental application needs. Options within each jacket material include coefficient of friction, cold temperature flexibility and temperature range, among others. Water-tolerant options are available that take advantage of tight-buffered cable qualities and super absorbent polymer aramid yarn.
Fiberglass or metal-braided jackets provide abrasion resistance and rodent protection. Custom rodent resistant cables are available that include metal or dielectric armor or additives to the outer jacket. “Exposed cable is often an intriguing temptation for animals, which can, and often do, chew on it,” says Hobbs.
Hybrid cables, connectors
For applications that can benefit from fiber optics and copper, hybrid connector-cables offer both within the same cabling sheath.
A distinct advantage of hybrid cable connectors is that they can bundled for the high performance of fiber with the copper power or control signals in one cable. This reduces the number of cables deployed. It also offers distinct savings in labor and cable structure costs for the customer.
“Genderless” connectors have both male and female elements, and perhaps are more appropriately described as “dual-gender.” They deploy quickly, allowing cable to be unreeled without regard for male or female ends.
OCC has further simplified the genderless design with user-friendly mating interfaces capable of “blind-mate” or applications requiring thousands of mating cycles. In addition, the connectors resist harsh mechanical and environmental conditions, including high vibration, mechanical and thermal shock and fluid immersion.
Another genderless-connector benefit is that multiple identical cable assemblies can be daisy-chained or sequenced together to extend deployable system’s distance while maintaining polarity. Polarity can be an issue when connecting an odd number of traditional male to female gender connectors. In such cases, an additional connector is required to correct polarity. However, such connectors are known for high loss. Genderless connectors are uniquely advantaged over traditional interconnection systems.
Distances of several kilometers are possible, limited only by system link budget (dBm). “This type of genderless connector provides extreme flexibility in the case of redeployment, where the length of the cable assemblies required for the next application are not fixed, or even known,” says Hobbs.
Key characteristics of a reel system in deployable fiber optic applications are that it is lightweight and stackable for storage and transit, says Hobbs.
OCC provides lightweight alternatives to traditional metal reels. Constructed of durable, yet lightweight, impact absorbing polymers, these modular advanced reel systems meet the demanding needs of harsh-environment fiber optic installations. Reels can be used with simple deployable axle or a flange supported deployment and acquisition system. These include A-Frames, cable acquisition cradles, transit case systems, tripods, bumper mounts, backpacks, backpacks with fiber optic slip rings and cartridge systems.
The cartridge system, which comes with casters, works well in many deployable applications. “Using a cartridge system, a single person can handle multiple spools at once and can quickly deploy fiber and rewind on the reel without assistance,” says Hobbs.
To simplify shipping and transit, cartridge systems, transit cases and reels have interlocking stacking features. Reel systems also provide a measure of protection of fiber optic cabling for unspooled cabling, or when the cabling is retracted.
“When you put fiber optic assemblies in a controlled environment storage system like a reel, the potential for damage to the cable or the connectors is minimized,” says Hobbs. “This reduces the need to refurbish components regularly, because it the system better protected during its deployment.”
Although deployable fiber optic systems are largely “wired,” hybrid cabling (the combination of fiber optic and copper/electrical within the same cable sheath) allows wireless access points installation anywhere, even underground. This is ideal when access points are constantly changing.
Unlike traditional wireless networking devices that require 110-Volt AC power for each device, with a hybrid system, power can be supplied in the same cable carrying voice and data. As a result, any 802.11-certified devices can communicate through the network, including personal devices such as PDAs, laptops, VOIP devices and cell phones.
Even deep within mines personnel can communicate with each other and even make calls outside the system. In addition, sensor-based data such as temperature, humidity, airflow and gas can also be collected and delivered wirelessly for use by the entire network.
According to Hobbs, many industrial companies are converting to fiber optics as component costs continue to drop, making fiber a better solution than copper in many applications.
“When system engineers realize the bandwidth opportunities, they usually expand their capabilities and identify creative new ways to enhance the solutions for their applications,” Hobbs concludes.
For more information about deployable fiber optic system for harsh environments, contact Optical Cable Corporation (OCC) at 5290 Concourse Drive, Roanoke, Va., 24019; Phone: (800) 622-7711, Canada (800) 443-5262; Fax: 540-265-0724; Email: firstname.lastname@example.org; Visit the website www.occfiber.com.