Lined Sight Flow Indicators
Lined Sight Flow Indicators
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Full technical data and dimensions
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PTFE Lined Tubular Sight Flow Indicator
Lined tubular sight glass, NB 1/2" to 16"
Lined tubular sight flow indicator giving 360° visibility of the whole bore — NB 1/2" to 16", available in PTFE, PFA and FEP across the entire range.
| Product type | Lined tubular sight flow indicator |
|---|---|
| Body / steel grade | Flanges IS 2062 plate / ASTM A 105 |
| Lining material | PTFE / PFA / FEP |
| Liner standard | ASTM D 1457 / ASTM D 4894-19 (PTFE), ASTM D 3307 (PFA) |
| Lining options | Virgin or anti-static (conductive black) PTFE to ASTM D 4894 & D 4895, PFA to ASTM D 3307, FEP to ASTM D 2116 |
| Flange standard | ASME/ANSI B16.5 |
| Flange class | Class 150 standard; Class 300 on request |
| Size range | NB 1/2" to NB 16" |
Product overview
What it does, and where it fits.
A tubular sight flow indicator replaces a length of the line with a glass tube between two lined flanges. Instead of two viewing ports you see the entire circumference and the full length of the section, which makes it the right choice for spotting settling solids, stratification or a slow-moving interface that a window would miss.
This is one of the few items in the lined catalogue where PTFE, PFA and FEP are all marked applicable across every size from NB 1/2" to 16". Face-to-face is short and changes little with bore — 175 mm at NB 1/2" to 230 mm at NB 16" — so it drops easily into an existing run.
An azeotropic separation type is available on request for watching and separating two liquid phases by density.
Features
Built into every unit.
- 360° visibility over the full length of the glass section
- PTFE, PFA and FEP available across the whole NB 1/2" to 16" range
- Short face to face — 175 mm to 230 mm regardless of bore
- Flanges IS 2062 plate or ASTM A 105 to B16.5 Class 150
- Azeotropic separation type on request
Benefits
Why it earns its place in the line.
- Sees the whole bore, not two ports — catches settling, stratification and interfaces
- Short, near-constant face to face makes retrofit straightforward
- Outstanding corrosion resistance to aggressive organic and inorganic chemicals across a wide temperature range
- Non-stick, non-wetting bore — low surface energy keeps product moving and simplifies cleaning
- Chemically inert and pure; no additives, plasticisers, stabilisers or lubricants to contaminate the process fluid
- The lowest coefficient of friction of any solid, reducing pressure drop and deposit build-up
Applications & industries
Where it is specified.
Typical applications
- Full-bore visual monitoring on corrosive lines
- Watching for settling solids or phase stratification
- Azeotropic and density-based separation observation
- Confirming complete drainage of a line
Industries served
- Chemical processing
- Pharmaceutical
- Petrochemical
- Oil & gas
- Power generation
- Pulp & paper
- Mining & metallurgy
- Agrochemicals & dyes
Technical data
Specification for PTFE Lined Tubular Sight Flow Indicator.
Figures below are for this product only — every item in the range carries its own dimension table.
| Product type | Lined tubular sight flow indicator |
|---|---|
| Body / steel grade | Flanges IS 2062 plate / ASTM A 105 |
| Lining material | PTFE / PFA / FEP |
| Liner standard | ASTM D 1457 / ASTM D 4894-19 (PTFE), ASTM D 3307 (PFA) |
| Lining options | Virgin or anti-static (conductive black) PTFE to ASTM D 4894 & D 4895, PFA to ASTM D 3307, FEP to ASTM D 2116 |
| Flange standard | ASME/ANSI B16.5 |
| Flange class | Class 150 standard; Class 300 on request |
| Size range | NB 1/2" to NB 16" |
| Temperature range | Continuous service to 260 °C (PTFE melting point 327 °C, PFA 306 °C, FEP 260 °C) |
| Pressure rating | ASME/ANSI B16.5 Class 150 flanges as standard; Class 300 available on request |
| Manufacturing standard | ASTM F 1545 |
| Spark testing | Every lined component spark tested at 5000 × E volts (E = liner thickness in mm), to a maximum of 15 000 V |
| Hydro testing | Hydrostatic or pneumatic test according to the lining technique; hydrostatic test on components with vent holes |
| Inspection | Dimensional and visual examination of liner and steel parts — weld aspect, overall dimensions, collar size, liner thickness, surface flaws and paint thickness |
| External protection | Zinc epoxy primer, minimum 60 μm dry film, over steel sand-blasted to SA 2.5 |
| Certification | EN 10204 3.1 mill certificates and FDA certification for the fluoropolymer available on request |
| Face to face | 175 mm to 230 mm, tolerance ±2 mm |
| Size | Face to face L (±2) | PTFE | PFA | FEP |
|---|---|---|---|---|
| 0.5" | 175 | ✓ | ✓ | ✓ |
| 0.75" | 175 | ✓ | ✓ | ✓ |
| 1" | 180 | ✓ | ✓ | ✓ |
| 1.5" | 185 | ✓ | ✓ | ✓ |
| 2" | 190 | ✓ | ✓ | ✓ |
| 2.5" | 195 | ✓ | ✓ | ✓ |
| 3" | 200 | ✓ | ✓ | ✓ |
| 4" | 200 | ✓ | ✓ | ✓ |
| 6" | 210 | ✓ | ✓ | ✓ |
| 8" | 210 | ✓ | ✓ | ✓ |
| 10" | 220 | ✓ | ✓ | ✓ |
| 12" | 220 | ✓ | ✓ | ✓ |
| 14" | 230 | ✓ | ✓ | ✓ |
| 16" | 230 | ✓ | ✓ | ✓ |
All dimensions in mm. All three lining materials are marked applicable across the full size range.
Available on request
- Special length (face to face)
- Stainless steel body
- Azeotropic separation type sight flow indicator
FAQ
Questions we are asked about this item.
Tubular shows the whole bore over the length of the glass, which suits settling, stratification and interface watching. A double window lets you look through the flow against a light, which reads colour and clarity better.
Ask us — a polycarbonate or acrylic shield is standard on the tubular sight flow indicators in our glass range and can be discussed for the lined version.
Separating two liquids by density while watching the interface — used on azeotropic distillation and solvent recovery duties.
Related products
Commonly specified alongside PTFE Lined Tubular Sight Flow Indicator.
Tubular Sight Flow Indicators
Tubular Sight Flow Indicators
Lined Pipes & Spools
Enquiry
Tell us your line size — we'll confirm the spec.
Send the bore, the media, the temperature and pressure, and the flange standard you work to. Drawings and custom sizes welcome.
Not sure which spec fits your process?
Send your requirement — media, temperature, pressure, dimensions — and we'll recommend the right product or fabricate it.
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