What fittings are suitable for miniature flat-bottom ports?
Small flat-bottom port fittings
Flat-bottom ports are popular designs for connection of semi-rigid tubing within fluidic systems at limited pressure. Although the dominating thread size is 1/4-28, several smaller flat-bottom port designs are also available. This includes regular 10-32 flat-bottom, 6-32 flat-bottom, and 6-40 flat-bottom designs, as well as special port arrangements using the same threading. These miniature flat-bottom port designs are often employed in microfluidic Life Science instrumentation that process low liquid volumes and when the physical space for connections is restricted. As summarized in the text and table below, Biotech Fluidics are supplying a range of fitting models manufactured for these mini flat-bottom ports.
Recommended fittings for 10-32 flat-bottom ports
The Super Flangeless™ fitting system provides the most powerful and comprehensive range to connect tubing with an outer diameter (OD) of 1/16” into flat-bottom ports with 10-32, 6-32, and 6-40 threading. The Super Flangeless™ design is recognised for providing leak-free connections even through vibrations and allowing tightening of the nut without twisting the tubing fittings, while still exposing the transported liquid only to contact with the biocompatible material PEEK. In addition, the Super Flangeless™ system is compatible with NanoTight™ FEP tubing sleeves of 1/16” OD, thereby enabling connection of capillaries with OD from 70 µm to 1 mm.
For 10-32 flat-bottom ports, the Super Flangeless™ M-250 PEEK ferrule, combined with the knurled head nut M-653, provides reliable connections up to 1,000–5,000 psi (69–345 bar) depending on tubing type and diameter. For those already familiar with these Super Flangeless™ fittings it should be noted that the legacy hex nut models M-652 and M-655 now are obsolete and have been replaced by M-653.
Alternative fittings for 10-32 flat-bottom ports
An alternative approach for 10-32 flat-bottom ports is to use the LT-111 Flangeless™ LiteTouch® nut together with the P-240 Flangeless™ ETFE ferrule for 1/16″ OD Tubing. This combination delivers affordable and biocompatible sealing up to 2,000 psi (138 bar).
Another option to connect 1/16” OD tubing to 10-32 flat-bottom ports is to use the P-844 VacuTight™ fittings. These are adapted for vacuum applications down to 25 in-Hg (84 kPa), and positive pressure systems up to 400–800 psi (27–55 bar) depending on tubing type and its wall thickness. The design of the included P-840 VacuTight™ ETFE ferrules provide reduced tubing deformation and therefore minimum flow disturbance.
Fittings for 6-32 and 6-40 flat-bottom ports
Super Flangeless™ fitting designs are also available for 6-32 and 6-40 threaded flat-bottom ports. The M-650 PEEK ferrule together with the M-644-03 nut is designed for connecting 1/16” OD tubing 6-40 flat-bottom ports. By instead combining the M-650 PEEK ferrule with the M-660 nut, 1/16” OD tubing can be securely connected to 6-32 flat-bottom ports. These Super Flangeless™ fittings will withstand pressures up to 750–3,750 psi (52–259 bar) depending on tubing characteristics.
The MINSTAC ports with 6-40 threads that are featured on products by The Lee Company has a special type of flat bottom design. Biotech Fluidics supply the TinyTight™ ferrules M-647 and M-657 for fluidic systems incorporating such components. Combined with the M-644-03 PEEK nut, these ferrules provide easy-to-use options for connecting 1/16” OD tubing to MINSTAC 6-40 port designs. The TinyTight™ fittings can withstand pressures up to 600–2,500 psi (41–172 bar) depending on tubing characteristics, and the two ferrule options provide different thru holes (0.020” for M-647 and 0.030” for M-657).
All the Super Flangeless™ and TinyTight™ fittings can be combined with 1/16” OD NanoTight™ FEP tubing sleeves, thereby extending the range of diameters that can be connected also to capillaries with OD from 70 µm to 1 mm.
More information
Follow the links below to the product pages for Super Flangeless™, Flangeless™, VacuTight™, and TinyTight™ fitting systems to learn more about each design. Or contact Biotech Fluidics to discuss your application requirements and for further advise about connecting 1/16” OD tubing to small flat-bottom ports.
Overview table
| Tubing OD | Flat-bottom port | Fitting system | Ferrules | Nuts |
|---|---|---|---|---|
| 1/16” +capillaries* | 10-32 | Super Flangeless™ | M-250 | M-653 |
| 1/16” | 10-32 | Flangeless™ | P-240 | LT-111 |
| 1/16” | 10-32 | VacuTight™ | P-844 | P-840 |
| 1/16” +capillaries* | 6-32 | Super Flangeless™ | M-650 | M-660 |
| 1/16” +capillaries* | 6-40 | Super Flangeless™ | M-650 | M-644-03 |
| 1/16” +capillaries* | MINSTAC 6-40 | TinyTight™ | M-647, M-657 | M-644-03 |
| *Capillary dimensions 70 µm–1 mm can be connected by using NanoTight™ FEP tubing sleeves with OD 1/16”. MINSTAC is a registered trademark of The Lee Company. | ||||
More information
Follow the links below to the product pages for Super Flangeless™, Flangeless™, VacuTight™, and TinyTight™ fitting systems to learn more about each design. Or contact Biotech Fluidics to discuss your application requirements and for further advise about connecting 1/16” OD tubing to small flat-bottom ports.
