Deployable fiber-optic systems for harsh industrial environments come battle-tested

By RICK HOBBS, Director of Business Development,Optical Cable Corporation (OCC) -- As the utilization of fiber optics has increased within the industrial sector, so have the number of “deployable” systems used in applications from oil and gas exploration, drilling and distribution to mining. As opposed to fixed installations, deployable systems are designed to be quickly installed, retracted, and then relocated in the field and even deep underground in some of the most inhospitable environments on earth.

Given the environments in which they reside, industrial-grade fiber-optic systems are typically commercialized versions of field-tested, proven military-grade products. As such, the component parts of the system are designed to withstand everything from dust and debris to chemical exposure, temperature extremes, UV, radiation, electrical power transients, interference, fire, moisture, humidity, water, crush, tension, flexing, impact, and vibration.

When designing a deployable fiber-optic system, it needs to be looked at in its entirety. Unlike fixed applications, a deployable system is designed from beginning to end (plug and play) and delivered to the customer as a complete solution. OCC designs and manufactures fiber-optic cable, connectors and assembly solutions for harsh and rugged environments. The primary elements of a deployable system 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.
-- Reel systems that speed deployment and retraction while protecting the fiber while not in use, or during transit.

Hardened cabling options are many

For purposes of deployment, experts typically recommend tight-bound, tight-buffered distribution style cabling, which is ideal because of its small diameter and lightweight construction. Distribution-style cables have a tight-bound outer jacket, which is pressure extruded directly over the cable’s core. This combination of 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, which are specifically tailored to meet the mechanical and environmental needs of the application. Options within each jacket material include coefficient of friction, cold temperature flexibility and temperature range, to name a few.

Water tolerant options are available that take advantage of the qualities of tight buffered cable and super absorbent polymer aramid yarn. Fiberglass or metal braided jackets not only provide excellent abrasion resistance, but also deliver increased rodent protection. In deployable applications, exposed cable is often an intriguing temptation for animals, which can, and often do, chew on it. Custom rodent resistant cables are available that include metal or dielectric armor or additives to the outer jacket.

Focus on: Hybrid Cables and Connectors and Genderless 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-connector solutions is that the customer can bundle both the high performance of fiber with the copper power or control signals in one cable. This reduces the number of cables that must be designed, purchased and deployed into a system. 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 are designed for quick deployment, allowing the user to unreel fiber cable without regard for male or female ends. In addition, the connector system is designed to resist extreme harsh mechanical and environmental conditions including high vibration, mechanical and thermal shock, and fluid immersion.

Another benefit of genderless connectors is that multiple identical cable assemblies can be daisy-chained (sequenced) together to extend the distance of a deployable system 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 and add additional components for the customer. Therefore, 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 re-deployment, where the length of the cable assemblies required for the next application are not fixed, or even known.

Reel systems minimize fiber damage

The key characteristics of a reel system in deployable fiber-optic applications are that it is lightweight and stackable for storage and transit. To meet these requirements, companies are providing lightweight alternatives to traditional metal reels. Constructed of durable, yet lightweight, impact absorbing polymers, these modular advanced reel systems are designed specifically for 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 types of systems 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, is an ideal choice 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. To simplify shipping and transit, cartridge systems, transit cases and reels are designed with interlocking stacking features. Reel systems also provide a measure of protection of fiber-optic cabling for unspooled cabling, or when the cabling is retracted.

In harsh environments, when you can put your fiber-optic assemblies in a controlled environment storage system like a reel, any potential damage to the cable or the connectors is minimized. This reduces the need to refurbish components regularly, because it the system better protected during its deployment.

Wireless access/data communications

Although deployable fiber-optic systems are largely “wired,” hybrid cabling (the combination of fiber-optic and copper/electrical within the same cable sheath) also allows for installation of industrial wireless access points 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 that also carries voice and data. As a result, any 802.11-certified devices are able to communicate through the network, including personal devices such as PDAs, laptops, VOIP devices and cell phones. This provides personnel even deep within mines with the means to 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.

Conclusion: Increasing conversion to fiber optics

There are many industrial companies that are converting to fiber optics as the costs for components continue to drop, making fiber a better solution than copper in most applications. Even die-hard copper devotees are moving to fiber and when they do, they rarely look back. When system engineers realize the bandwidth opportunities, they usually expand their capabilities, and identify creative new ways to enhance the solutions for their applications.

Rick Hobbs serves as Director of Business Development - Military, Specialty & Harsh Environment and General Manager of AIS Products for Optical Cable Corporation (CC). Rick has more than 19 years of experience in networking and system solutions including business development, product management, technical sales and operations management. Rick operates out of OCC’s Plano, Texas facility.

For more information about deployable fiber optic system for harsh environments, contact Optical Cable Corporation (OCC) at 5290 Concourse Drive, Roanoke, Virginia, 24019; Phone: (800) 622-7711, Canada (800) 443-5262; FAX: 540-265-0724; Email: [email protected]; Visit the web site www.occfiber.com.