Down through an open full port
The ball valve is open and the gland is loose. The probe is lowered through the full-port opening into the line — nothing is throttled, and the bore is wide enough for the probe body to pass.
Clean the window without stopping the line.
An optical probe in a resin line will foul. The question is not whether it needs cleaning, but whether cleaning it costs you production. A full-port ball valve and a retraction chamber mean it does not — the pipeline stays under pressure while the probe comes out.
Scroll
The insertion and retraction cycle
Eight positions of one assembly, drawn as it is drawn in the file: gland, retraction chamber, full-port ball valve, weld boss. Scroll moves the mechanism.
Fig. 1 · DWG SPX1-INS-01 · Rev. A
8 steps · illustrative, not to scale
Sealed at measuring depth
With the optical window at the right depth in the flow, the gland is tightened around the probe shaft. From here the assembly holds against process pressure.
16 barprocess pressure125 °Cprocess temperature
The window is in the product
Excitation light leaves the window into the flowing resin and the scattered light returns on the collection fibre. This is the state the assembly spends almost all of its life in.
5 smeasurement to value24/7continuous duty
Before anything moves
Measurement finished, the gland is released. The probe is still in the line and the valve is still open — nothing has been isolated yet.
Up into the chamber
The probe is withdrawn into the retraction chamber, which carries its own internal seals around the shaft. The tip now sits above the valve, clear of the bore.
The ball turns ninety degrees
With the probe clear, the valve closes and the process is isolated. Only now can the gland be opened safely — the sequence, not the operator's judgement, is what keeps that order.
The probe comes out, the line does not stop
The probe is withdrawn fully through the gland and the optical window is cleaned. In practice this lands in the between-batch purge, when the line is being blown clean anyway and no product is flowing — so the service costs no production time.
Back in, and round again
The probe returns to the retraction chamber with the gland loose, ready for the valve to reopen and the cycle to repeat. Nothing in the sequence requires the line to be depressurised or drained.
No depressurisationline stays liveNo drainingno product loss
Retraction cycle · step 01 / 08
What servicing costs, with and without the assembly
Every inline optical instrument in a fouling medium faces the same maintenance question. The mechanical design is what decides whether the answer involves production planning.
A fixed window turns maintenance into a shutdown
To reach an optical window that is welded into the line, the section has to be depressurised, drained, opened and recommissioned. The instrument stops being an asset and becomes an item on the shutdown plan.
The same job, inside an existing window of time
Isolate, withdraw, clean, re-insert. The line stays under pressure and the product stays in it. Because the operation is short, it fits in the gap that already exists between batches.
Which is why the measurement survives contact with reality
Analysers get abandoned not because they measure badly but because keeping them measuring becomes somebody's problem. The mechanical design of the probe assembly is what keeps that from happening.
The probe is automatically withdrawn from the circulation loop, rinsed with a stream of solvent, and returns to the measurement position. Gekko Photonics · Główny Mechanik
Servicing · step 01 / 03
Four parts, in the order they matter
Everything in the drawing exists to make one thing possible: taking the probe out of a live line and putting it back.
Full-port ball valve
The bore is as wide as the pipe, so the probe passes through it rather than around it. Rotated ninety degrees it isolates the process, which is the precondition for opening anything above it.
Weld boss
The permanent connection to the line. It is welded once, and everything above it is serviceable.
Retraction chamber
Carries internal seals around the probe shaft and holds the withdrawn probe clear of the valve bore.
Gland
Mounts and seals the probe at measuring depth. Its state — loose or sealed — is what the sequence is really about: it is never opened while the process side is live.
The probe itself
- Type
- immersion, Raman, 785 / 1064 nm
- Diameter · length
- 12 mm · up to 465 mm
- Wetted materials
- 316L · fused silica · resistant epoxy
- Housing
- 316L or POM-C / POM-C ESD (ATEX)
- Process pressure
- 16 bar
- Process temperature
- −40 … +125 °C
- Process pH
- 2–10 continuous · 1–14 short-term
- Protection · zone
- IP67 · ATEX / IECEx Zone 0
- Connections
- DN32/40/50 PN16 · ANSI 1¼–2" Cl 150 · NPT 1¼" · Tri-Clamp 1½" and 2"
0
Litres of product drained to clean the optical window. The retraction chamber and the full-port valve are the whole reason that number is zero — and the reason an inline analyser stays in service past its first fouling event.
And the laboratory side of the same platform
The retractable assembly is what keeps a measurement running. The bench instrument is what makes it exist in the first place.
X1 LAB / LAB+ — where the method is built
Benchtop measurement of vials, cuvettes or sealed containers, with a carousel of up to 25 samples and library matching against more than 28 000 reference spectra in LAB+.
- Acquisition
- 5–300 s per sample
- Sample prep
- little or none
- Enclosure
- IP20 · USB
The transfer to the line
Same optical geometry, same detector behaviour, same model format in Spectrally OS — so the calibration built during feasibility becomes the production system's first calibration rather than a discarded pilot.
- Feasibility
- 3–5 samples · 1–2 weeks
- Workshop to working system
- 3–5.5 months
- Model updates
- 12 months in the agreement
Two versions of this page
This one leads with the mechanical sequence — the drawing, the valve, the cycle. Version 1 leads with the installation as a whole: process connection, the fibre run out of the hazardous area, the hand-off to PLC and DCS, and the laboratory path as a scroll sequence of its own. Same facts, different entry point.