Fluids with which quick disconnects commonly work include air, chemicals, fuel, gas, hydraulic fluids, oil, solid transfer, steam, and water. Quick disconnects are simple products, but they are important to all applications that could potentially require an easy and fast solution to fluid spillage or mingling.
Efficient flow applications and products that quick disconnect couplings serve include agricultural sprayers, automotive systems, chemical and food processes, shut-off valves, ball valves, construction, firefighting hoses, and gas transfer.
Safety applications in which quick disconnect couplings are key include those in the aerospace, fuel, and first response industries. For instance, because aircraft fuel is extremely combustible, aircraft fuel tank hoses are all equipped with dry disconnect couplings; they reduce spillage that could lead to fires or fume inhalation. Quick disconnect couplings are important to emergency service applications including emergency decontamination, emergency oxygen supply, and firefighting.
The first quick disconnect coupling products were commissioned by various governments for the military during World War II. They wanted couplings that they could apply and remove more easily than pneumatic couplings. Those pneumatic couplings that they used before not only had to be applied and removed with tools, but they were also stubborn and slowed down service people and their use of vehicles and equipment.
After the war, manufacturers realized the general usefulness of quick disconnect couplings and expanded their use. Today, manufacturers use quick disconnect couplings for a diverse set of applications, from connecting garden hoses to connecting oxygen lines.
Manufacturers select coupling fabrication materials based on the types of liquids they will be helping transport and the application details in general. Some of the materials available for coupling fabrication include metals like carbon steel, stainless steel, copper, brass, nickel-plated brass, bronze, and aluminum. For higher flow applications, manufacturers often select stainless steel. Manufacturers also offer quick disconnect couplers made from a variety of plastics. While manufacturers make the majority of couplings from metal, they are starting to make more and more from plastic. Plastic couplings are becoming more popular because they cost less to make and exhibit excellent corrosion resistance.
Considerations and Customization
When designing or assigning quick disconnect couplings, manufacturers think about a number of things, including application temperature range, application pressure (psi) range, application fluid flow type, flow line diameter, and frequency of use. In addition to offering quick release couplings equipped with the ability to handle a wide range of high temperatures and high flow psi, manufacturers also offer couplings equipped to assist fluid transfer lines of a wide variety of sizes. Typically, they offer couplings ranging in size from one eighth of an inch to ten inches in diameter. Also, to make them more effective, manufacturers sometimes safe-tie quick connect disconnect couplings with wire.
How They Work
Quick disconnects are usually operated manually instead of automatically because many machines cannot not be programmed to respond to an unexpected change. Most, however, only require the use of one hand. Plus, operators do not need the assistance of tools, though some older models are still operated with a wrench.
To perform connecting and disconnecting actions, operators turn an interlock mechanism, such as a nut. Generally speaking, to connect a quick disconnect coupling, an operator pulls back a female fitting end and pushes it onto the male end of a hose or tool with at least one valve. Then, to complete the connection, the fittings releases, thus activating the coupling, opening the valve, and allowing fluid to pass through in both directions. When an operator disconnects the coupling, a spring pulls the valve shut, stopping anything from coming or going.
The fact that the system shuts down almost immediately after the coupling is disconnected is an important feature of quick disconnect couplings. Without such expediency, a system leak could rapidly become a large problem.
Quick release couplings are made in a variety of different configurations, in order to accommodate their many applications.
Quick release coupling types include plain connectors, sleeve and poppet couplings, single-poppet connectors, double-poppet connectors, sliding ball couplers, hydraulic quick disconnects, air quick couplers, breakaway couplers, dry disconnect couplings, ball couplers, and camlock couplings.
Plain connectors, as their name implies, are the simplest and least expensive type of quick coupling. They connect the female and male with the assistance of a ball-bearing sleeve lock.
Sleeve and poppet couplings allow zero fluid loss and do not permit air to enter into a poppet valve system.
Single-poppet connectors, which work well with applications that allow for minor spillage, close off the supply of liquid using a single seal.
Double-poppet couplings use two seals to isolate liquid on both sides, trapping only a negligible amount of fluid between the valves and eliminates the step of collecting or draining the lines of spilled product before disconnecting the coupling.
Sliding seal couplers are used to ensure minimal spillage in hazardous chemical applications. To keep space for potential bacteria and dirt small, they place seals flush to the exposed ends of the male and female halves.
Hydraulic quick disconnects, or hydraulic quick couplings, are a specialized type of disconnect coupling. They are designed to efficiently connect and disconnect fluid lines in hydraulic systems while maintaining fluid pressure and not introducing air.
Air quick couplers are specialized couplings designed to work with air, and in particular to facilitate connections between air compressors and pneumatic tools. In the right setting, they may be called quick air compression fittings. Air quick couplings are of good quality, but because air spillage generally poses a smaller threat, if any, the seals they use are not as tight or as quick as those used by others.
Breakaway couplers are customarily utilized during the transfer of hazardous materials; because they remain open during normal operation but close quickly when faced with excessive force, they minimize product loss and safety hazards.
Dry disconnect couplings are equipped with a device that is a variation on the mechanical internal lock, which prevents accidental openings and releases. In order to release the coupler from the pipe or hose, the valves must be closed and sealed off by identical discs in the male and female halves. They provide drip-free connections where hazardous materials are handled or in sanitary environments.
Ball couplers are couplers that hold flow lines together using balls. When an operator pushes a button, the balls, which are distributed on either or both the female and male bodies, draw in and connect the two halves. Once the balls are in place, the operator can release the button and the two halves will lock in the connected position.
Camlock couplings, also known as cam and groove hose couplings, are couplings used most often with chemical and petroleum flow lines. They feature a female coupler and a male adaptor. The coupler and the adaptor connect via the coupler cam arms and the adaptor grooves. Together, they create a strong gasket seal.
Quick disconnect couplers offer their users a variety of benefits. First and foremost, they make coupling connection and disconnection easy. They eliminate the clumsiness inherent with threaded hook couplings, which can cause issues such as hose kinks. The speed with which users can couple or uncouple a hose can be very important in settings like emergency services.
Another advantage of quick disconnect couplings is that they are also more secure than other couplings. This is especially true of those designed specifically to stop leakage between both connected and disconnected lines. An added benefit of secure couplings is decreased environmental impact and a lower risk of injury to workers by leaked chemicals.
Examples of quick disconnect fitting accessories include protective dust caps, protective dust plugs, housings, and breakaway clamps.
To make sure your couplings work well and serve you for a long time, you must first make sure they do not become contaminated when you’re not using them. The best way to do this is by covering them with plugs and caps during disuse.
Next, during use, you need to make sure that you never use a coupling to connect lines that pump higher levels of pressure than that for which the coupling is designed. If you do run fluid lines that exceed high pressure recommendations, the couplings could fail. At best, this would be an inconvenience, and at the worst, this would cause extreme injury, death, or damage to environment. Likewise, never run fluids through coupled lines that a coupling is not designed to handle. For example, if your coupling is made from a material that cannot handle chemicals without corrosion, do not use it to connect lines that transport such chemicals.
Finally, we also recommend that, in addition to exercising common sense, any coupling operators familiarize themselves with the safety guide your supplier provides.
Almost universal is the requirement that quick disconnect couplings meet the appropriate ISO (International Standards Organization) standards. ISO puts out standard series related to a number of different quick disconnect coupling types, such as hydraulic couplings, cylindrical couplings, etc. Examples of common ISO series include ISO 7241 series A, ISO 7241 series B, both which deal with hydraulic quick disconnect couplers. ISO series are interchangeable with a number of series offered by prominent companies. Examples include Snap-Tite 72 series, Hansen HK series, Safeway S10 series, Parker 74 series, and Parker 60 series. ISO also offers guidelines related to dimensional requirements.
In addition to ISO, you need to make sure that your quick disconnect fittings meet the standards required per your location, industry and application. To find out what those might be, reach out to your industry leaders.
Things to Consider
The best way to get a set of quick disconnect fittings that work for you is by connecting with a coupling supplier with your best interests in mind. Find a supplier like this by checking out those we have listed on this page; every manufacturer we have listed has a record of excellence. Of course, just because a manufacturer is great for someone else does not mean that they are great for you. To discern between them, we recommend you start by putting together a specifications list that details not only your application requirements, but your project allowances, such as budget and delivery deadline. Once you’ve put your list together, you can browse ours. Based on your specifications, pick out three or four quick disconnect coupling manufacturers in which you’re most interested. Then, contact each of them to discuss your project with a customer service representative. Take notes and/or request they email you a summary of the conversation with a quote. Finally, compare and contrast your conversations and pick the manufacturer you believe will best serve you. Happy hunting!