When it comes to industrial connectors, many industries have a need for connectors that are able to operate in a harsh environment. Traditionally, the military has been the source for connectors used on equipment operating at environmental extremes. In many fields, however, industrial equipment manufacturers are dealing with environments that exceed that of many mil-spec connectors. Industries that lead the field include: machine tool, oil and gas, mining, railway, entertainment, food, medical, and security (including commercial and homeland). In many cases, the military is adopting connectors built for the industrial segment for use in military hardware. 

Whether it is on a drilling platform operating in the middle of an ocean, in a factory where caustic chemicals are being utilized, or in another extreme environment; industrial manufacturers are building equipment that operates effectively and reliably in challenging situations. Selecting connector technology and materials that can meet tough requirements is key to successfully building equipment for these conditions.

Industrial equipment manufacturers are constantly faced with new challenges with respect to the selection of components to meet the environmental requirements of their products. While not all industrial products are destined for operation in an unprotected environment, standard commercial connectors are often inadequate for the demands of even “ordinary” use in the factory, which, in fact, can be a hostile environment. Depending upon products being produced, the presence of dust, fluids, and caustic chemicals are common in factories around the world. It can be challenging to make equipment that is capable of operating in this day-to-day setting.

Various parameters affect the selection of connectors for use in the factory. Issues of cleanliness around the production of food and pharmaceuticals often result in connectors that will be subjected to water and cleaning agents, as required for sanitary operation of the facility. Electrical interference, due to the operation of heavy machinery, must be taken into account. Factories that work with wood and agricultural products, such as grains that are ground for various products, generate dust. Other applications and the ensuing problems they generate are endless.

For facilities that are not in controlled environments, the situation can get even worse. The high level of automation and process control, being supplied to previously manual tasks, causes electronic equipment to be in places they have never been. High temperatures in steel and other metal producing mills subject connectors to heat extremes and result in a need for new materials and design features.

When products move outdoors, the situation often escalates. Off-shore oil rigs require all kinds of electrical and electronics to operate. The salt-water, rain, and oil are just a few of the parameters that must be considered when selecting connectors for use. These platforms are usually connected via underwater cables to land-based equipment. Signals must travel through salt-water, and the connectors used in this situation must be able to be permanently immersed in the sea.

Underwater connections are commonplace, as cables now cross the oceans for communication and control functions. In a white paper, Dave Jenkins of Ocean Design Inc., says, “Wet-mateable electrical and fiber-optic connector technology has evolved to a level where reliable underwater connections can be made at full ocean depths.” Using oil filled, pressure-balanced connectors, the mating and unmating can be done under water; saving time and money for the maintenance of underwater cables. Both fiber-optic and copper cables can be serviced when these connectors are employed.

Industrial Connector Manufacturers

Not surprisingly, many of the full military connector manufacturers are also in the industrial connector market. Amphenol, a military market leader, has a complete line of connectors built for industrial use. ITT is active in the mass transportation market. Glenair, Deutsch, Souriau, Harting, Samtec, Lemo, Smith Industries, and others all make products for the industrial market.

In addition to those that are known as military connector suppliers, many of the large commercial connector suppliers, such as Harting, Samtec, and Lemo, also have industrial connector lines. Tyco, the number one connector supplier, has a major offering in industrial connectors. Molex, the number two worldwide connector supplier, also has an industrial connector presence that has just been strengthened by their acquisition of Woodhead Industries.

Selection Factors

The connector chosen for a specific application is driven by the environment in which it will operate. The connector selection will consider both the materials of the product and the configuration of the internal pieces. The need for strength in the connector enclosure and the physical abuse it may experience during use must be considered, along with internal features like o-rings, threaded assembly, or other mechanical features.

Many times the connector must be able to operate in an environment that subjects it to water, whether during its operational time or just during the cleaning process. Dust and other particles also have a potential to affect operation. Helping the industrial designer are standards that identify the ability of a component to withstand the ingress of particles, dust, and fluids. Depending on the application, having this data can be useful in selecting parts that will meet the required environmental exposure. The tables below are a synopsis of the IP (Ingress Protection) specification and show the levels of protection and the definition.

Table 1 – Protection against Penetration by Foreign Objects

Table 2 – Protection Against Ingress of Water

When choosing a connector for a harsh environment application, an IP-rated product is often used. The IP or “Ingress Protection” specification has a two-digit component that identifies the degree of protection. The first digit is the protection from penetration by foreign objects, and the second is the protection from the ingress of water. The specification lists the designations and contains requirements that must be met to qualify for the assigned rating. The ratings are also used for larger components such as enclosures.

The above charts indicate that a connector meeting IP65 would be dust-tight and able to have water jets projected from any angle with no harmful effects. However, that same connector might fail if it were subjected to a high-pressure or steam-jet cleaner.

Such data are extremely important when connectors are chosen for applications where these conditions are present. In pharmaceutical or caustic chemical manufacturing environments, equipment is routinely cleaned with high-pressure water or steam to maintain the equipment or the sterility of the environment. Materials such as stainless and plastic are both candidates for use in a caustic environment. The desire is that there is no reaction from the connector coming in contact with the environment. But all stainless steel is not equal. It is necessary that the stainless contain at least 11% chromium to be resistive to the environment. Stainless does this by the formation of a chromium oxide barrier. The oxidation is part of a process known as passivation, which is the process of making a material passive, or non-reactive, to other materials.

In the case of pharmaceuticals, the presence of caustic chemicals and the need for high-pressure cleaning implies the use of passivated materials and the selection of components that prevent the ingress of water. Cannon’s IP69K-rated R14 connector would be an example of a stainless steel connector meeting the stringent pressurized water jet resistance.

Products for Harsh Environments

The products to meet almost any need in the industrial environment are readily available. From heavy, sealed connectors for use on large earth-moving equipment to sealed RJ-45 connectors for Ethernet controlled equipment, the scope of connectors available is impressive. Following are just a few of the offerings that give a glimpse of the available products.

Below is a series of connectors from Amphenol for RJ45, USB-A, USB-B, RJ11, IEEE1394, LC, and MTRJ cordsets in a rugged plug, which will protect it from shock, dust, and fluids. On the right is an optical connector.

The picture below shows a circular filter connector from Sabritec of Smith Industries

Conclusions

These are just a few of the available connectors for the harsh environment industrial market. The breadth of product is enormous. For just about any environmental situation, a product already exists. As new connector technologies emerge, the makers of harsh environment connectors will find a way to encapsulate it in a connector shell to ensure its survival under the most hostile conditions.

Rick Lewis, director of industrial and military markets, joined Bishop & Associates in 2003. Most recently, Lewis was the data (computer) segment manager for FCI, with a prior position at FCI as the telecom segment manager. Lewis comes from the military electronics design world where he began as a computer designer. He was a Fellow in digital design at Westinghouse and taught “Design with Microprocessors” and “Assembly Language Programming” at the School of Applied Sciences (an after work college level course for employees). While with Westinghouse (which was acquired by Northrop Grumman), Lewis held positions in marketing and program management and was active in customer presentations and customer interaction, in addition to engineering.

While at FCI, Lewis participated in many of the international committees that established the various standards for the connector industry. He was responsible for monitoring the industry and identifying trends and common needs. He participated in many cross-functional product teams to develop connectors that included several companies from Europe, the U.S., and Asia-Pacific. His understanding of the underlying technology and software of the electronics industry gives him a unique view of the industry.