Quick Release Couplings

View A Video on Quick Release Couplings - A Quick Introduction

Quick release couplings can also be called quick connect couplings, quick disconnect couplings, quick disconnect couplers, quick couplings, quick connectors, quick disconnects, breakaway couplings and many other names. Air quick couplers are used to make connections between air compressors and pneumatic tools. In hydraulic systems, hydraulic quick disconnects are used to quickly connect and disconnect fluid lines without losing fluid pressure or introducing air. Quick disconnect fittings are often designed to be operated with one hand without the aid of tools, though some models still require the use of a wrench. Quick release fittings are used in many industries where the efficient flow of fluids with quick and easy disconnection is necessary, such as in gas transfer, firefighting hoses, agricultural sprayers, automotive systems, chemical and food processes and in the construction industry. Quick couplings also help ensure safety. For example, aircraft fuel tanks are filled by hoses equipped with dry disconnect couplings because the fuel is extremely combustible and couplings reduce spillage. This prevents accidental fires and inhalation of fumes by the operator.

Quick couplings are operated by connecting the female end onto the male end of a hose or tool. At least one of the ends has a valve, and when the valve opens, the quick coupling is connected, allowing fluid to flow through in either direction. When it is disconnected, a spring closes the valve, preventing fluid loss and the entrance of air. This happens quickly, shutting the system down almost immediately. The quick disconnect coupling can be connected or removed by turning an interlock mechanism, such as a nut. A quick disconnect is always operated by hand rather than by machine because something unexpected could happen to which a machine could not respond. Some installations require the quick disconnect coupling to be safe-tied with wire. The majority of quick release couplings are composed of metal materials, such as brass, aluminum or stainless steel. However, plastic couplings have increased in popularity due to their corrosion-resistant properties and lower cost. Common working fluids include air, hydraulic fluids, steam, water, oil, fuel, chemicals, gas or solid transfer. Sizes range from 1/8 inches to ten inches in diameter, and they can usually handle high pressures and temperatures.

There are variations of couplings that are advantageous to use in certain situations. Air quick couplers are used when working with air. Because "spilling" air is not typically dangerous, the seals used in these couplings are not as quick and tight as they are in other systems. Breakaway couplers minimize product loss and safety hazards by remaining open during normal use and closing rapidly under excessive force. They are typically used during the transfer of hazardous materials. Hydraulic systems utilize hydraulic quick disconnects because of their enhanced durability and strength, which minimizes the loss of fluid and pressure. A quick connector is a device that joins two or more parts together in order to prevent leaking or a drop in pressure. In a coupling, the male tip can be referred to as the connector. Quick connectors or quick disconnects can also refer to couplings or fittings. A quick release fitting or quick disconnect fitting is a general term given to a part that simply connects two pipes or hoses together without valves or seals. One main difference is that couplings can rotate while connected, but fittings cannot. Dry disconnect couplings are used in sanitary conditions or where hazardous materials are handled. They provide a drip-free connection and have a variation of a mechanical internal lock to prevent accidental releases and openings. Before the coupler can be separated from the hose or pipe, the valves are closed and sealed off by identical discs in the male and female halves.

Quick release couplings are available with a variety of connection designs. The simplest and least expensive are plain connectors, which join the male and female with a ball-bearing sleeve lock. Single-poppet connectors have one seal to close off the supply of liquid and are frequently used for applications when a minor spillage is acceptable. Double-poppet couplings, however, have two seals that close off both sides. This traps only a small volume of fluid between the valves. Though more mechanically complicated than other options, the double-poppet eliminates the need to collect spilled product or drain the lines before disconnecting the coupling. A sleeve and poppet coupling experiences zero fluid loss and does not allow air to enter the system. Other quick release coupling types include double rotating ball, sliding seal and stapler couplers. Sliding seal couplers have seals flush to the exposed ends of the male and female halves, which allows little space for dirt and bacteria. They are used for hazardous chemicals for minimum spillage. When chosen carefully and applied correctly, quick release couplings can be invaluable assets to their users.

Quick Release Coupling Types

• Air conditioner couplings are used in refrigeration and cooling system applications. Air conditioner couplings are designed to withstand vibrations without disconnecting and to minimize any refrigerant leakage once disconnected.
• Air Quick Couplers are used in air compression systems to connect hoses quickly without leaking air or losing pressure.
• Ball connectors have a number of balls on one or both of the male/female bodies that are drawn in when a button is pressed. Once the balls are drawn in, the two halves are connected and the button is released, projecting the balls and locking them in place. 
• Breakaway couplings are designed to permit a steady flow of material until excessive force is exerted on the coupling; it then pulls apart to avoid damage to the system and can be reassembled quickly by one person without tools or spare parts. 
• Connect-under-pressure couplings use a valve to relieve backpressure. This design makes it simpler to insert the hose into a receiver when hydraulic lines must be connected or disconnected.
  
• Double shut-off quick-release couplings have shut-off valves in both the male and female halves.
  
• Dry disconnect couplings are used at liquid transfer points to prevent excess spillage and to decrease the hazards typically found when handling/processing corrosive, toxic, caustic or other harmful products.
  
• Drybreak couplings are sliding, sleeve-style, quick disconnect couplings for hydraulic systems. Drybreak couplings are capable of connecting with little air inclusion and can be disconnected with minimal or no spillage.
  
• High flow couplings are used in application in which larger volume flow is required. High flow couplings can be made of polypropylene (PP), polysulfone, brass and stainless steel, among other materials.
  
• Hydraulic quick disconnects are any type of quick disconnect that is used in a liquid system. Hydraulic couplings commonly contain shut off valves to prevent spillage and reduce air inclusion when connecting/disconnecting.
  
• Non spill couplings are resistant to a wide range of media. Standard nonspill couplings come with non-spill shut-off valves, color-coding that delineates a variety of media lines, olefinic overmolding, which makes the connection more durable and improves the grip for users and seals and springs formed from materials that are determined by the amount of chemical resistance required.
  
• Non-valved quick-action couplings do not have shut off valves in either the male or female halves.
  
• Pneumatic couplings, also called "single shut off (SSO) couplings," are generally used to connect tools, equipment and hoses that utilize compressed air. Pneumatic couplings may also be used in applications in which other gases and low pressure liquids are in use.
  
• Poppet couplings are a type of valve used in hydraulic quick disconnects that disables fluid flow when the two mating halves are separated. The poppet-style quick disconnect coupling is one of the most popular hydraulic couplings.
  
• Push-and-pull quick disconnect couplings typically have a sleeve on the female half that is pulled back and into which a male tip is inserted, locking it into place when the sleeve is released. To disconnect, the sleeve is once again pulled back, and the male half is withdrawn.
  
• Quick action couplings are often used to separate or join hydraulic lines. The quick action coupling eliminates the need for tools or special devices.
  
• Quick connect couplings are composed of two mating halves used to join two pipes together. Within a quick connect coupling, there is a male plug and a female coupling. In order to connect the two, the male plug is inserted into the opening in the female half. Quick connect couplings are designed to prevent leakage from the line and often are fitted with shut-off valves for this purpose.
• Quick connectors are devices that are used to join two or more pipes, hoses or tubes together in order to prevent leaking or a drop in pressure.
• Quick couplings are used to join two pipes or hoses or a combination of the two together. They are composed of two mating halves: a male plug and a female coupling. In order to connect the two, the male plug is inserted into the opening in the female half.
• Quick disconnect couplers are mechanical devices that allow immediate connection and separation of air and fluid lines. They are designed to prevent spillage and are equipped with seals and valves for this purpose.
• Quick disconnect couplings are used to join together two hoses, pipes, or a combination of the two. They are designed to make connections without allowing leakage or a loss in pressure. They are used in the transport of many different materials, including water, gas, air, hydraulic fluid, and various chemicals.
• Quick disconnect fittings are non-mechanical parts that connect pipes and hoses together without valves or seals.
• Quick disconnects are used to connect pipes and hoses quickly without leaking or losing pressure. They are simple mechanical devices that can usually be connected with only one hand.
• Quick-release couplings form watertight connections between corrugated hoses, pumps, filters, etc. that can be easily disconnected and reconnected without the use of tools. Quick release couplings are simple to align and can withstand a wide range of water pressures.
  
• Single shut off quick-action couplings have a shut off valve in either the female or male half only.
  
• Threaded couplings are best suited for high pressure and high flow applications. To form a connection, the male half of a threaded coupling is screwed into the female acceptor, both of which are threaded, and turned clockwise; the male half is turned counterclockwise to disconnect the coupling.

Quick Release Coupling Terms

Air Inclusion - Ambient air that is forced into a system during the connection of quick disconnect coupling mates.

Brinelling - Grooves or dimples that are worn into the shoulder of a male half. These deformations are engendered by the locking balls of a female body.

Breakaway Clamp - A device that clamps to hold the sleeve of the quick disconnect coupling, which permits movement of the body. The movement is either forward within a single or double-acting sleeve upon disconnection, or backward within a double-acting sleeve upon connection.

Connector - Any device that is used to join two or more parts together. In quick disconnect couplings, the male tip is often referred to as the connector.

Connect-Under-Pressure Rating - The designation given to a coupling that refers to its ability to be connected with applied pressure from one or both sides of the hosing.

Coupler - A part used to connect multiple pieces together. Female acceptors are referred to as couplers in quick disconnect couplings.

Double-Acting Sleeve - A sleeve that allows for pull-to-disconnect and push-to-connect.

Dust Cap - A removable device that protects the male tip from everything but contamination when it is disconnected from the female body.

Dust Plug - A removable device that protects the female body from everything but contamination when it is disconnected from the male nipple.

Female Body - The accepting half of the coupling. The female body consists of an opening that contains locking balls to keep the male end in place.

Flow Checking - Also called "ball checking," "lock-up" or "check-off," it is the closure of the male tip half valve during high flow conditions, such as the rapid lowering of a heavy loader.

Inside Diameter (ID) - The distance measured from an inner surface of a quick disconnect coupling to the innermost point directly opposite the original mark. Equal inside diameters between connectors and hosing ensure equivalent flow rates throughout the system.

Interchange - The variations in locking design between internal coupler mechanisms and external nose configurations.

Locking Balls - A series of small, circular-shaped objects that project and retract from a female body. Locking balls allow for the insertion and withdrawal of the male nipple.

Male Tip - The nipple-shaped coupling half. The male tip is inserted into a female body and kept in place by locking balls.

National Taper Pipe Thread (NPT) - A standardized groove design for threaded parts for the United States.

Pivot Joint - A connector assembly that is able to turn in multiple directions.

Poppet Valve - A machined, self-aligning valve that typically offers higher flow than ball valves. Elastomers are incorporated into poppet valves to provide a positive seal upon disconnect and to prevent low pressure leakage.

Pounds Per Square Inch (psi) - A unit of measure of pressure. The maximum rated PSI for quick disconnect couplings must meet or surpass that of the other system components to ensure reliable performance.

Spillage - Fluid or air loss in a system due to the disconnection of a coupling device.