Making connections in harsh places
The essential features connectors must have to survive the most extreme environments
By Christian Taylor, Engineering – Team Leader. Bulgin
While most of us live and work in relatively protected and safe indoor environments, much of the world’s most critical electronic systems and equipment operate in harsh conditions. Whether it’s water, dust, extreme weather, explosive atmospheres or pressure, a range of harsh environments can create challenging conditions for these systems and their connectors to operate in.
One of the most common points of damage in any electrical system is where cables get plugged in - the connector. Connectors are at the junction of system and cable, needing to have the flexibility to mate and disconnect easily yet securely, all while keeping the elements out. As the guardians of the entry points to both system and cabling, their integrity in harsh environments is critical.
Since they’re at the entry point to the system, connectors face the same hazards as any electronic system, including water, dust/dirt, extreme temperatures, potentially explosive “ATEX” environments, pressure/weight, and salinity.
What Defines a Harsh Environment?
Wet or dirty environments with water, high humidity/water vapour, dust or dirt can wreak havoc on electrical equipment, causing short circuits or malfunctioning equipment. If salinity is a factor, such as in a seaside environment, corrosion can also be a serious issue.
Electrical systems are also often sensitive to temperature extremes, which can cause components to fail or malfunction. For data connections, Electro-Magnetic Interference (EMI) can be an issue as it can disrupt wired communication.
Physical force is another hazard which can come in the form of mechanical shock and vibration or pressure. To withstand shock and vibration, a robust mating method needs to be in place. Connectors in undersea, aerospace or pressurized environments also need additional ruggedization.
For connectors used in explosive environments, an additional requirement is that they do not have any way to set off a spark, either mechanically or electrically, and cause a hazardous explosion.
The range of rugged applications is extremely varied and crosses many industry lines. Ruggedized systems and connectors are used in industrial, marine, oil and gas, transportation and infrastructure, telecom, and more.
In industrial environments, automation, machinery and measurement come together to create today’s hyper-efficient manufacturing systems. Industrial environments are often exposed to a variety of harsh elements including water, vibration, chemicals and temperature extremes. The move to greater automation and “Lights-out” manufacturing means environmental challenges will only increase as equipment now increasingly has the freedom to operate in inhospitable conditions.
Industrial equipment such as food slicers, saws, sandblasters, food processors, coating machines can generate significant shock and vibration, as well as create dust or airborne contaminants. Sealed, rugged metal or plastic housing connectors with IP66, IP67, IP68 and IP69K ratings can withstand these harsh conditions and keep power, signal and data connections secure.
Because of the noisy EMI conditions in industrial environments and the dependence on sensors and communication, EMI is also a concern for data connections. In these cases electrically shielded connectors are ideal.
Marine applications include surface and undersea environments. Surface marine applications such as boating equipment, ship deck systems, or marina facilities face threats from corrosion due to high salinity, as well water ingress, making robust, sealed components essential.
IP rated components should be chosen depending on the level of water and dust protection needed, with IP66 and IP67 sufficient for many surface applications while IP68 or IP69K will be necessary when connectors may be submerged. For undersea applications such as diving electronics, depth loggers or undersea remotely operated vehicles, IP69K or other pressure-resistant designs are important.
Oil & Gas
The Oil & Gas industry faces many of the same environmental hazards of industrial and marine environments, but also must deal with explosive atmospheres which require the use of ATEX / IEC Ex rated equipment. For offshore platforms, both marine hazards and explosive atmospheres exist. In addition, the oil and gas industry makes extensive use of underwater ROVs for drilling and construction support as well as exploration.
These underwater remotely operated vehicles are essentially remote-controlled robots. They require power, data, and often fiber optic lines, have to operate in rough undersea conditions, and are often asked to go to depths beyond what’s possible by a human diver. Bulgin’s ROV tether connector is designed to keep these robotic helpers working reliably in uncertain waters. Made of 316 Marine-grade Stainless steel, it is a Pressure Balanced Oil Filled (PBOF) cabling solution that uses oil as a compensating fluid for water pressure, allowing ROVs to go to depths of 7000m.
From transportation and infrastructure to automotive and agriculture, a wide variety of applications operate in the outdoors. These use cases require connectors that can weather extreme temperature changes, water and dust ingress, physical duress, and more.
IP rating – IP ratings define the level of protection from dust and water ingress of the component. The first digit indicates the level of dust protection and goes from 0 to 6, while the second digit indicates liquid ingress protection. For harsh environments, sealed connectors should always be dust-tight, with water ingress protection depending on the application.
IP66 - protection against powerful water jets, and IP67 - immersion up to 1m, is suitable for many above water applications where systems may be rained on, or otherwise repeatedly exposed to water. Connectors which may be continuously submerged should be at least IP68 (immersion to 1m or more) or greater, and for undersea applications, IP69K (close-range high pressure and high-temperature spray downs) provides protection even under pressure.
Besides undersea and immersion applications, IP68 and IP69K also have medical and food processing use cases as these ratings allow the equipment to be regularly washed and sanitized without harm to electrical components.
With many connectors being exposed to environments with shock and vibration present, a robust coupling mechanism is a must. There are many different types of connector couplings, including ring, twist locking, threaded, bayonet, push-pull and quick disconnect couplings, all with different attributes for various types of applications. Some, like the bayonet connector, provide better security against shock and vibration, while others like push-pull and quick disconnect provide greater ease of use when connectors may need to be disconnected often.
Housing and insulation
The material the connector is made of helps it resist the challenges of its environment. For applications with temperature extremes as well as plenty of moisture and dust, a corrosion resistant metal housing may be appropriate. If lightweight and flexibility are key, temperature-resistant plastic composites will be more attractive.
The connector’s shape, mating mechanism and pin positioning also play a part in its ruggedness. Circular connectors have the benefit of easy engagement/disengagement, as well as the capacity to fit a wide variety of contacts. Circular connectors also are easy to seal and less likely to wear out. An intelligent “scoop proof” design can be used to avoid pin damage while trying to mate the connector.
Making the Right Connections
Our world is becoming increasingly connected. From outdoor cellular base stations to connected factories, to IoT sensors on oil and gas platforms, electronics are being placed in every environment imaginable. The electronic systems have to be guarded against all the forces of nature.
As the point of entry to the system, connectors have to be robustly designed to seal off and protect against all environmental challenges present - from shock and vibration to dust and water, or EMI. Thankfully today’s connectors from companies like Bulgin provide strong ruggedization for just about every application on the market. Through choosing the right IP rating, locking mechanism, housing material, and connector design, almost every rugged use case today can be made to work reliably with the right connector.
Bulgin manufactures a range of industry-leading rugged connectors, fuse holders, battery holders, switches and indicators designed for use in the most challenging of environments. Headquartered in Cambridge, UK, Bulgin also has offices in all key global regions and an extensive sales and distribution network spanning 65 countries. Its manufacturing facilities are based in the UK and Tunisia.
Visit http://www.bulgin.com/ for more information.