Description
A quartz flange forms the interface between a quartz tube and the surrounding system, such as a furnace door, vacuum connection or another process tube. In a fused tube-to-flange assembly, the flange is flame-welded to the tube as a continuous quartz-to-quartz joint. The core purchasing specification is therefore the complete interface geometry — tube OD, flange OD/ID, neck length and mating face — rather than the flange as an isolated disc shape.
Ground joints, ball-and-socket joints, threaded ends and compression connections are alternative quartz connection formats. They are quoted from the same interface drawing but are not all fusion-welded flange types.
Dimensions
| Parameter | Specification |
|---|---|
| Flange OD / ID | Matched to the mating hardware and tube OD |
| Tube OD Interface | Matched to the Quartz Glass Tubes hub range, 2 – 500 mm OD |
| Neck Length | Specified to the required stand-off and assembly geometry |
| Mating Face | Ground or polished face for O-ring / gasket compression where required |
| Bolt-Free Interface | No bolt holes in the quartz flange itself unless specifically required; sealing is normally achieved by external compression hardware |
Flange & Connection Types
| Type | Detail |
|---|---|
| Single-End Flanged Tube | One flange fused to one end of the quartz tube; the opposite end remains open, closed or otherwise processed |
| Both-Ends Flanged Tube | Flange interfaces fused to both ends for a complete chamber or transfer-tube assembly |
| Conical Ground Joint | Mechanical, vacuum-tight mating connection between precision-ground quartz parts; not a welded flange interface |
| Ball-and-Socket Ground Joint | Spherical ground connection allowing minor angular adjustment before the final seal is made |
| Externally Threaded Tube | Machined/threaded mechanical connection used where a threaded interface is preferred to a flange |
| Compression Flange | O-ring based connection used with external compression hardware; KF-port-compatible geometries can be produced to match the connected system |
Welding
- Quartz-to-quartz attachment by hydrogen-oxygen flame fusion welding.
- Tube-to-flange geometry is aligned concentrically before fusion to control runout and seal-face position.
- Post-weld stress relief is performed by flame annealing or furnace annealing according to part size, precision and value.
- Large-diameter flanged tubes require tighter control of tube roundness, wall variation and flange alignment than small-diameter assemblies.
Furnace & Vacuum Interface Use
Furnace Tube Flange
The flange geometry is matched to the furnace door, O-ring, liner or chamber hardware. For diffusion and oxidation equipment, the furnace OEM interface drawing controls flange OD, opening, neck length, face geometry and tube position.
Vacuum System Flange
Quartz tube assemblies can be produced to mate with KF-type or equivalent external vacuum hardware. The quartz part provides the optical, thermal or chemical process path, while the final vacuum rating depends on the complete seal stack and connected hardware.
Material
Standard assemblies use clear fused quartz, typically Type I / GE214-equivalent material for general thermal and process service. Higher-purity semiconductor-grade quartz can be selected for plasma, etch or contamination-sensitive interfaces when the chamber specification requires tighter impurity control.
What to Specify
| Parameter | Quotation Input |
|---|---|
| Tube Interface | Tube OD, ID or wall thickness and required finished tube length |
| Flange Geometry | Flange OD, opening ID, thickness and neck length |
| Mating Face | Ground / polished; O-ring or gasket contact geometry |
| Configuration | Single-end flange, both-ends flange, ground joint, ball joint, threaded or compression connection |
| System Match | Furnace model, door geometry, vacuum port size or existing mating-part drawing |
| Alignment | Any concentricity, face runout or flange-to-tube orientation requirement |
FAQ
Is the flange a separate piece bolted to the tube, or part of the tube?
For a fused tube-to-flange assembly, the quartz flange is flame-welded to the tube so the finished component is one continuous quartz assembly. External clamps, O-rings or mating hardware may still be used to seal that assembly into the system.
Can you match a flange to my existing furnace door pattern?
Yes. Provide the furnace door, O-ring and tube-interface dimensions from the OEM drawing and the quartz flange geometry can be matched to that interface.
Do you offer both-ends-flanged tubes, or only single-end?
Both configurations are available. Each end can also use a different interface when the assembly requires, for example a fused flange on one side and a ground-joint or compression connection on the other.