Lab Plastic Tube Connectors

A tight slip fit between the connector barb and the tubing inner diameter prevents leaks under pressure. Measure the inner diameter of your tubing in millimetres before ordering. The most common laboratory tubing bore sizes are 4 mm, 6 mm, and 8 mm. Using a connector that is too small creates a restriction; too large allows slippage and leaks.

Straight connectors extend a run in a straight line. Y-connectors split one inlet into two outlets at an angle, ideal for equal flow division. T-connectors add a branch at 90 degrees to an existing run, suitable for manifolds. Choose based on the geometry of the system you are building.

Polypropylene connectors resist most dilute acids, alkalis, and aqueous solutions and can be autoclaved. Polyethylene is softer and more flexible but has similar chemical resistance. Avoid PP with concentrated aromatic solvents. For gas applications, check that the connector material is compatible with the gas being transported.

GL14 is a standard metric thread designation for laboratory bottle connections. Before ordering a GL14 hose fitting, confirm that the bottle cap is also GL14 threaded. GL14 caps have an inner thread diameter of 14 mm. Other common sizes are GL18, GL25, and GL45, which are not interchangeable with GL14 fittings.

Most PP tube connectors are sized by the inner diameter of the tubing they accept. Common sizes are 4 mm, 6 mm, and 8 mm inner diameter. The connector barb is slightly larger than the stated bore so that the tubing grips the barb tightly when pushed on. Always state the tubing inner diameter when ordering connectors.

A Y-connector splits one inlet into two outlets at a symmetrical angle, typically 60 degrees to the inlet axis. A T-connector adds a side branch at 90 degrees to a straight-through run. Y-connectors are used for equal flow division into two parallel lines. T-connectors are used to tap off a branch while maintaining the main flow straight through.

Yes, barbed plastic tube connectors can be used with gas lines provided the connector material is compatible with the gas and the tubing is a tight fit on the barb. For pressurised gas above approximately 0.5 bar, use a cable tie or hose clamp over the tubing at each barb to prevent blow-off. Never use damaged or cracked connectors on pressurised gas lines.

GL14 is a standardised metric thread used on small laboratory bottles and their matching caps. A GL14 hose fitting is a threaded insert that screws into a GL14 bottle cap and provides a barbed hose connection for attaching flexible tubing. They are used on wash bottles, reagent dispensing bottles, and small aspirator vessels. GL stands for Gewinde Luer, the German standard for laboratory thread sizes.

Push the tubing onto the barb as far as it will go, ensuring the barb is fully inside the tubing. For applications with moderate pressure, apply a small cable tie over the tubing at the barb. If the tubing slips despite this, the tubing bore may be too large for the barb. Check that you have the correct combination of tubing inner diameter and barb size, and replace with the correct size.