Custom Spiral, Helical & U-Shaped Quartz Tubes

Parameter	Typical Range	Notes
Tube OD / ID	4–30 mm	Smaller tube forms tighter bends
Minimum bend radius	~3–5× tube OD	Tighter radius increases wall deformation
Coil OD	20–300 mm	Confirm per configuration
Pitch	1.2–3× tube OD	—
Turns	2–20	Confirm per configuration
Leg length tolerance	±0.5 mm	Precision cut-to-length

Inquiry

Spiral, Helical & U-Shaped quartz glass product image 1

Quartz Glass flame-forms straight quartz tubing into U-bends, spirals, and helical coils for heating elements, fluid paths, and lab setups that need a formed shape rather than a straight run.

Tube OD, bend radius, coil OD, pitch, and turn count all move together — a smaller bend radius increases cross-section deformation and forming difficulty, which limits how tight a coil can be made at a given tube OD. Quartz Glass has confirmed U-bend, spiral/coil, and flame-forming capability; exact size limits for your configuration are confirmed against the drawing.

Bend Radius, Coil Diameter, Pitch and Leg Length

Bend radius is the number that drives everything else on a formed tube. Too tight a radius for the tube OD thins the outer wall of the bend and can collapse the bore slightly — both are checked during inspection. Coil OD, pitch, and turn count are then set relative to that minimum radius, not chosen independently.

How to Dimension a Quartz Coil or U-Bend

Send these together rather than one at a time: tube OD/ID, bend radius (or coil OD if that's the driving dimension), pitch, number of turns, and leg length at the straight ends. For a U-bend specifically, leg length and the angle between legs both need to be on the drawing — a bend radius alone doesn't fix the finished shape.

Flame Forming, Coil Forming and Joined Assemblies

Forming is done by localized flame heating and controlled bending or winding — the tube is heated only where it bends, not along its full length, to keep the straight sections true. After forming, the part gets a local anneal at the bend to relieve stress from the heating and shaping. If your design needs the formed section joined to a straight run or a flange, that weld is added after forming and annealing, not before.

Inspection covers bend radius, pitch, overall height, leg length, symmetry between turns, cross-section deformation at the bend, and cracks.

≥2×Reference Bend Radius / OD

30–150 mmReference Coil OD

0.5–15 mmGeneral Wall Envelope

1–20+Turns to Drawing

≥99.99%Natural SiO₂ · synthetic ≥99.999%

≤1100 °CContinuous Service Guideline

Specifications

Spiral, Helical & U-Shaped Tube Specifications

Parameter	Reference Capability / Requirement
Tube OD / ID	Selected with flow, heating duty and bend geometry
Minimum Bend Radius	Reference centerline radius ≥2 × tube OD; final limit is geometry-dependent
Coil Outside Diameter	Reference 30–150 mm
Pitch	Axial distance per turn, specified on the finished coil
Number of Turns	Drawing-specific
Leg Length	Straight inlet and outlet sections dimensioned from tangent points
Overall Height / Width	Controlled by coil OD, pitch, turns and end orientation
Wall Control	Reviewed at the outside and inside of the bend
Annealing	Stress relief after flame forming and welded joints

Standard Series

Reference U-Bend & Coil Geometry Series

Form	Reference Geometry	Controlled Dimensions	Typical Function
180° U-bend	R ≥2 × OD	Leg spacing / leg length	Fluid routing and compact heaters
90° bend	R ≥2 × OD	Tangent lengths / orientation	Equipment connections
Single-turn loop	Coil OD 30–150 mm	Loop plane / end angle	Radiant heating and optical paths
Helical coil	OD 30–150 mm	Pitch / turns / overall height	Heat exchange and fluid preheating
Flat spiral	By drawing	Inner / outer diameter	Planar heating and reaction paths
Multi-section assembly	Formed + welded	Port and flange datums	Custom reactors and process skids

Dimensional Tolerances

Formed-Geometry Inspection Requirements

Feature	Size / Condition	Reference Tolerance
Bend Radius	Centerline	Checked with finished-part gauge
Coil OD	30–150 mm reference	Drawing-specific after forming
Pitch	Per turn	Drawing-specific
Leg Length	From tangent point	±0.5 mm standard where geometry permits
End Orientation	Inlet / outlet	Angular datum specified on drawing
Wall Section	Inside / outside bend	Verified after forming
Overall Envelope	Width / height	Finished-part gauge or CMM inspection

Configurations

Bent, Coiled & Formed Tube Configurations

U-Shaped Tube180° bend with parallel or offset legs

Serpentine PathRepeated U-bends for compact flow or heating length

Helical CoilConstant coil OD and pitch around a center axis

Flat SpiralPlanar winding with controlled inner and outer diameters

Single LoopOne-turn circular path with oriented inlet and outlet

Conical HelixChanging coil diameter along the axis

Milky Quartz Heater CoilDiffusing specialty quartz for infrared heating

Welded Formed AssemblyCoils combined with ports, straight sections or flanges

Material Selection

Quartz Grades for Heating & Fluid Paths

Electric-Fused QuartzGrade-specific UV cut-offOH 5–150 ppm; heat treatment can adjust OH. General-purpose continuously drawn stock. Confirm UV boundary by grade datasheet.

Flame-Fused Quartz · JGS2220–2500 nmOH 120–260 ppm; UV-visible optical components.

Synthetic Fused Silica · JGS1185–2500 nmSiO₂ ≥99.999%; OH ≈1000 ppm. Selected for deep-UV transmission; strong OH absorption near 2730 nm.

Vacuum-Fused / Low-OH · JGS3Grade-specific UV–IR / 260–3500 nmVacuum-fused OH <3 ppm; JGS3-class OH ≤10 ppm. Use the lot certificate and transmission curve at the working thickness.

OH content varies by grade and batch; the lot certificate is authoritative. Compare material routes and typical transmission data.

Fabrication

Flame Bending, Coil Forming & Annealing

Mandrel / Gauge SetupFinished centerline geometry converted into forming controls
Flame BendingLocal heating controls radius while limiting wall collapse
Coil FormingCoil OD, pitch and turn count developed around the tool
End OrientationStraight legs and connection angles set after forming
Quartz WeldingPorts, flanges and straight extensions joined to the formed tube
Stress-Relief AnnealingApplied after forming and welding before final inspection

Applications

Formed Quartz Tube Applications

Infrared HeatingMilky or transparent coils around radiant heating elements

Fluid PreheatingHelical paths increase residence time in a compact envelope

Condensation SystemsQuartz coils for corrosive or high-purity vapor handling

Laboratory ReactorsU-bends and coils integrated with vessels and ports

Gas DistributionFormed paths route gases around thermal or optical assemblies

Optical & UV SystemsQuartz loops and shaped paths around lamps and samples

FAQ

Frequently Asked Questions

What is the minimum bend radius?

A reference starting point is a centerline radius of at least 2 × tube OD. The final limit depends on OD, wall, bend angle and material grade.

What dimensions define a quartz helix?

Specify tube OD/ID, coil OD, pitch, number of turns, overall height, leg lengths and inlet/outlet orientation.

Can milky quartz be formed into heater coils?

Yes. Opaque or milky quartz can be reviewed for infrared heater coils, subject to raw-tube size and forming geometry.

Can formed tubes include ports or flanges?

Yes. Formed sections can be welded to straight tubes, branches and quartz flanges, followed by stress-relief annealing.

Need a spiral, helix or U-shaped quartz tube?Send the centerline geometry, tube size, bend radius, coil OD, pitch, turns and end orientation.

Open the Tube Configurator

Engineering Data

Grade-Qualified Material Purity

Electric-fused / flame-fused quartz: SiO₂ ≥99.99%; synthetic JGS1-grade fused silica: ≥99.999%. Grade and lot certificate govern supplied material.

Engineering Data

Service Temperature

Transparent quartz: continuous use ≤1100 °C; short-term excursions ≤1200 °C. Opaque / milky quartz: continuous use ≤1000 °C. Load, atmosphere, support span and thermal cycling determine the application limit.