Connecting and disconnecting actions are performed by turning an interlock mechanism like a nut. Quick disconnects are usually operated manually instead of automatically because a machine could not be programmed to respond to an unexpected change. Most, however, only require the use of one hand and operators do not need the assistance of tools, though some older models are still operated with a wrench. 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 fitting is released, activating the coupling, opening the valve, and allowing fluid to pass through in both directions. When the coupling is disconnected, a spring pulls the valve shut, stopping anything from coming or going. Some quick disconnect couplings are also safe-tied with wire. 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.
Some of the materials available for coupling fabrication include metals like stainless steel, brass, or aluminum, as well as a variety of plastics. While the majority of couplings are made from metal, those made from plastic are becoming more popular all the time because they cost less to make and exhibit excellent corrosion resistance. Equipped to handle high temperatures and pressures, couplings range in size from one eighth of an inch to ten inches in diameter.
Quick release couplings are made in a variety of different configurations, in order to accommodate their many applications. Quick 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, and dry disconnect 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 system. Next, single-poppet connectors, which work well with applications that allow for minor spillage, close off the supply of liquid using a single seal. Similarly, 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 are a specialized type of disconnect coupling, designed specifically to efficiently connect and disconnect fluid lines in hydraulic systems while maintaining fluid pressure and not introducing air.
Likewise, air quick couplers are specialized couplings designed to work with air, and in particular to facilitate connections between air compressors and pneumatic tools. 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.
Next, 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. Finally, 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. Other quick disconnect coupling types include stapler couplers and double rotating ball couplers.