NW Glass Flanges

These flanges are available in sizes ranging from 10mm ID to 160mm and come with mating knuckle clamps and teflon centered oring. They are essentially the glass equivalent to stainless steel KF flanges, and can be used to interface with the metal KF series. We stock 10/16, 25, 40, 50 and 69 mm ID glass flanges and their corresponding clamp assemblies and teflon seal sets.
They are designed for high vacuum use,  with a leak rate of  <1x 10-9 mtorr / sec.

NW 50 flanges

These flat flanges have proven to be useful in the fabrication of electrochemical cells and microbial fuel cells; basically any cells requiring sealing a membrane, such as Nafion®, between sides. See a sketch here of how they connect, and hold membranes. 

There are two flavors of clamp; the white knuckled clamps are rated to 100°C, and the autoclavable black "high temp" knuckles, rated to 150°C.

NW Flanges and Componenets

NW Flange w S/S

NW flange detail

You can see many images of these flanges in context by searching
NW flanges in the gallery

Note - the thickness of your intended membrane effects the clamping distance between flanges; a membrane thicker than ~.020" (0.5 mm) will require some accommodations in order for the clamp to hold correctly. Please let us know if you intend to mount a membrane thicker than .020"

 They are useful for mounting windows as well. We also offer borosilicate plates to close off the flange and provide a clear window, as well as quartz plates to allow for UV transmission, most often for photoelectrochemical uses. The diameter of the plate is the same as the outside diameter of the associated flange.

Quartz windows

Flange dimensions below;
The OD is accurate, the rest approximate.

  Flange OD   Tube OD   Inside Diam  
  inches mm inches mm inches mm
NW10 1.18 30 0.63 16 0.47 12
NW16 1.18 30 0.79 20 0.63 16
NW25 1.58 40 1.18 32 1.02 26
NW40 2.17 55 1.75 45 1.57 40
NW50 2.95 75 2.21 56 2.05 52
NW63 3.43 87 2.91 75 2.76 70

The seal ring is the same for both NW10 and NW16 with a 16 mm inside diameter, so there will be a larger contact area on one side of the membrane when using the smaller NW10 to hold a membrane.

It is possible to overtighten the clamps. Please see a PDF of our notes about their use.


Below, these flanges provide flexibility and versatility in an elaborated vacuum manifold.

Diphosphine Synthesis Line Detail

Shown below is the largest version of this flange, an NW160. It has an ID of 150mm, just under 6", for easy access to the interior.NW160 glass flanges and clamp

Below is a large 2-part cyclone assembly utilizing NW flanges, both for access to the interior of the cyclone itself, through NW160 flanges, as well as for porting through the NW50 flanges.

big 2 part cyclonelarge cyclone