Determining Connection Type
Fittings, luers and couplings are the most common tubing connectors. While each is appropriate for certain types of applications, they are not necessarily interchangeable; it’s important to specify the connector that satisfies your specific application requirements.
Fittings are offered in many different types, sizes and material options. They’re a popular choice for applications that don’t require the disconnection of equipment or parts at any point during production or use. It’s important to note that fittings—and instant fittings—do not have shutoff valves, so flow does not stop when the tubing is disconnected. Another consideration is the speed and ease of the connection. If it is important that the equipment be assembled quickly, and if the fluid lines will not need to be disconnected again, then a fitting or an instant fitting offers a viable, low-cost connector solution.
There are two types of luer connectors—slips and locks. A luer slip connector consists of a tapered “male” fitting that slips into a similarly tapered “female” fitting. They are typically held together by a simple pressure and twist fit. The luer lock connector has a threaded collar added to the “male” fitting and a threaded flange on the “female” fitting that screw together. If the application doesn’t need a valve to prevent spills and the connector needs to be disconnected only occasionally, a luer is often a good choice.
Designed for repeated connection and disconnection cycles, standard couplings—with or without valves—allow tubing to be reliably connected and disconnected without the use of tools. If the equipment needs to be assembled quickly, or includes fluid lines that will need to be disconnected for servicing or repair, then a coupling offers the most advantages.
In many cases, the integral shutoff valves available in couplings are a primary driver in the decision to specify a coupling over a simple fitting or luer. Quick disconnect couplings with integrated non-spill shutoff valves save time by eliminating spill cleanup and provide the added security of virtually drip-free connection and disconnection.