Optical Fibre Gas & Pressure Control | Alicat, Equilibar, Drastar UK

Optical Fibre Production — Gas & Pressure Control (UK)

From MCVD/OVD/VAD preform deposition and helium‑assisted fibre drawing to UV coating and ribbonising, optical fibre lines demand precise, fast and repeatable control of gases, pressure and liquids. Any drift in oxygen, chlorine, helium or dopant flows, or instability in chamber/back‑pressure, can introduce refractive‑index errors, micro‑bends, coating defects and yield loss.

Premier Control Technologies supplies and supports Alicat Scientific mass‑flow and pressure controllers, together with Equilibar back pressure regulators and Drastar high‑purity pressure regulators, across the UK.

Preform manufacturing (MCVD / OVD / VAD)

Typical challenges

Ultra stable low flow dosing of oxygen, chlorine and dopant gases for soot deposition and sintering
Fast step changes / pulsing during gas switching without overshoot or long settling
Purity and pressure stability from gas cabinets to tool inlets

Why Alicat here

Sub sccm to slpm accuracy & speed: Alicat's laminar differential pressure architecture with integrated P&T compensation gives fast response and broad turndown, ideal for MCVD recipe steps and dopant transitions.
Multi gas, multi range flexibility: Switch gases (O₂, Cl₂, He, Ar, specialty dopants) and ranges on instrument to accelerate R&D and changeovers. COMPOSER™ supports user gas mixes without factory recalibration.
Pressure control: Alicat PC/PCS units stabilise line or chamber pressure to decouple flow pressure interactions during burner ramp/soak.

Support components

Drastar UHP regulators (two stage/cylinder & line): electropolished 316L SS, metal diaphragms and VCR® options keep gas purity and low droop into MFCs. Ideal in gas cabinets and hook ups feeding MCVD.

Equilibar back pressure regulators (BPRs): frictionless multi orifice design maintains stable exhaust back pressure even at ultra low flows and with condensable by products—improving deposition uniformity.

Fibre drawing (draw tower, He cooling, primary/secondary coat)

Typical challenges

Helium consumption & stability: keeping He flow steady through transients to control cooling rate and micro bend risk
Draw tension pressure effects: fast, stable pressure response around the furnace and capstan zones
Resin coating quality sensitive to back pressure and viscosity changes

Why Alicat here

Low ΔP, vacuum friendly variants support accurate flow where upstream pressure is limited; fast control reduces overshoot during tension/speed changes.
Integrated data & totalisation (analog + Modbus/serial) provide high rate data for statistical process control and helium usage optimisation.
Direct pressure control with Alicat PCs keeps draft/line pressure stable through pump downs or valve movements, reducing draw instability

Support components

Equilibar BPRs on coating/exhaust loops damp pressure spikes and hold setpoint with mixed phase or changing viscosity, improving concentricity and cure uniformity. High temperature options up to ~450°C are available where needed.
Drastar line regulators upstream of MFCs stabilise inlet pressure to the tower’s He and N₂ lines, improving MFC accuracy and reducing settling time.

Ribbon forming (stack, matrix, UV cure)

Typical challenges

Consistent inerting and purge: for matrix application & UV cure
Pressure stability : in low flow manifolds feeding multiple fibres
Recipe agility for development lines

Why Alicat here

Fast, repeatable control at sub sccm flows keeps purge levels and O₂ ppm stable in enclosures.
Multi gas libraries and on device range changes accelerate trials (e.g., switching N₂/Ar or tweaking purge rates).
Compact systems / gas mixing: your gas mix skids built with Alicat MFCs simplify commissioning and provide plug and play recipe control for multi fibre ribbon lines.

Support components

Equilibar BPRs + electronic pilot (Alicat PC) provides high resolution back pressure control for matrix delivery or exhaust, with minimal hysteresis.
Drastar point of use regulators (single/two stage) ensure clean, stable supply at the ribbon station while protecting downstream instrumentation.

Why Alicat is a strong fit for optical fibre producers

Speed & stability at ultra low flow: Millisecond class control dynamics with pressure & temperature compensation maintain precise mass flow in sensitive deposition and purge steps.
Broad turndown & multi gas capability: One instrument covers R&D and production ranges, reducing spares and downtime; COMPOSER™ supports custom gas mixes.
Connectivity for process intelligence: Analog (0–5V, 4–20mA) and digital (Modbus/RS 232, etc.) plus onboard totalisers simplify DAQ/PLC integration and traceability.
Clean construction options: 316L SS and metal seal variants align with high purity requirements common on preform and draw tools.

Equilibar & Drastar for fibre

Equilibar BPRs — frictionless, multi orifice diaphragm regulators offering exceptional resolution from ultra low to high flows, compatible with mixed phases and condensable; ideal for MCVD exhaust, coating back pressure and pilot controlled precision loops (with an Alicat PC as the electronic pilot). High temperature variants available.
Drastar high purity regulators — electropolished 316L, tied metal diaphragms, UHP VCR®/face seal options and low droop for gas cabinets, cylinders and point of use regulation (O₂, He, Cl₂, dopants). They provide stable, clean supply pressure into Alicat MFCs, improving accuracy and shortening settling times.