Compressed Air Quick Disconnect Guide
An ultrasonic instrument used to detect flaws in a compressed air system can help companies discover leaks that are not audible to the human ear. Leaks can not only cost significant wasted dollars but also lessen the effectiveness of the compressed air system. Many sub-audible level leaks can be attributed to worn couplers and plugs. By following the suggested coupler and sleeve selection practices when repairing leaks, a facility can save up to $600 in energy costs per year by repairing just 10 poor connections.
Quick Disconnect Coupler Types
The history of an easy-to-operate quick coupler design begins in the 1940s when militaries were seeking to replace a pneumatic coupler design that required tools and was difficult to remove and reconnect. These first quick couplings came to be known as the Industrial Interchange design. Today, four major design types, ranked by their popularity, are available: Industrial (Milton), Automotive (Tru-Flate or Parker), ARO, and Lincoln.
Universal or combo couplers are designed to make plug and coupling connections interchangeable. Identification of a universal coupler is usually indistinguishable, therefore their use is not foolproof and the interface will encounter a leak, which is not always audible.
Generally, there is no advantage of one style of quick disconnect over another; however, there are a number of guidelines to follow to select the correct fitting for the application. When considering a quick-disconnect coupling, ensure that it carries a sufficient flow capacity and can tolerate the compressed air inlet pressure. In addition to the system requirement, follow these guidelines in selecting your compressed air couplings:
- Use wear-resistant material or coating couplers and plugs, such as coated steel, hard-anodized aluminum or nickel-plated brass.
- Coupling connections should be made using a 4-ball design at a minimum. Two-pin designs have a tendency to rock from side to side causing air leakage.
- The best way to ensure a good fitting quick-disconnect is to check that the coupler and plug types in your facility are uniform or differentiated, as different types do not interconnect.
Both standard and universal couplings can incorporate a sleeve that is either a snap-ring or a positive-stop coupler. In the snap-ring style, the coupler sleeve is simply held by a snap-ring, while a positive-stop sleeve has an immovable end surface to protect against movement of the sleeve.
For sleeves, a positive-stop sleeve coupler is preferred over snap-ring styles. While cost may be an advantage of snap-ring couplers, they hold a key disadvantage compared to a true sleeve style. Snap-ring couplers are easy to inadvertently pull back and release the male plug. Not only could the plug spontaneously release and cause compressed air loss, but the snap ring can also dislodge causing a compressed air and hose whipping work hazard.
Because of the numerous couplers present in a typical industrial setting and the frequency at which they can become comprised, it is vitally important to have periodic facility compressed air leak detection audits to reduce energy use and it is also beneficial to be conscientious of the materials utilized in repair or installation.