Lined Fittings

PTFE Lined Spectacle Blind

Name: PTFE Lined Spectacle Blind
Brand: Lata Scientific
SKU: ptfe-lined-spectacle-blind
Availability: InStock

Lined figure-8 blind, NB 1" to 18", 16–40 mm

Lined figure-8 spectacle blind — swing it one way to isolate, the other to open, with positive visual proof of line status. NB 1" to 18" in PTFE, PFA and FEP.

Request a quotation Full technical data and dimensions Request the datasheet

At a glance
Product type	Lined spectacle blind (figure-8)
Body / steel grade	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), ASTM D 2116 (FEP)
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" to NB 18"

Product overview

What it does, and where it fits.

A spectacle blind is a figure-of-eight plate with one solid disc and one open ring, bolted between two flanges. Slackening the joint and swinging the plate either isolates the line absolutely or opens it — and because the plate projects beyond the flange, anyone can see from the ground which state the line is in. That visual certainty is why spectacle blinds are specified for positive isolation before entry and maintenance work.

The lined version keeps a fluoropolymer face on the process side in both positions, so the isolation point does not become the corrosion point. It is offered NB 1" to 18" in thicknesses from 16 mm to 40 mm, with PTFE, PFA and FEP all marked applicable across the range.

Features

Built into every unit.

Figure-8 plate — positive isolation with visual confirmation of line status
PTFE, PFA or FEP facing across every size NB 1" to 18"
Thickness 16 mm at NB 1" to 40 mm at NB 18"
IS 2062 plate or ASTM A 105 to B16.5 Class 150
Class 300 drilling and stainless steel bodies on request

Benefits

Why it earns its place in the line.

Positive, provable isolation for permit-to-work and vessel entry
Line status readable at a glance from outside the pipework
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

Positive isolation before vessel entry and maintenance
Battery-limit isolation between plant sections
Seasonal or campaign isolation of a lined branch
Hydrotest boundaries during construction

Industries served

Chemical processing
Pharmaceutical
Petrochemical
Oil & gas
Power generation
Pulp & paper
Mining & metallurgy
Agrochemicals & dyes

Technical data

Specification for PTFE Lined Spectacle Blind.

Figures below are for this product only — every item in the range carries its own dimension table.

PTFE Lined Spectacle Blind — technical specification
Product type	Lined spectacle blind (figure-8)
Body / steel grade	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), ASTM D 2116 (FEP)
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" to NB 18"
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
Vent holes	3 mm diameter vent holes — one per fitting; spools under 500 mm get a single central hole, spools over 500 mm get two holes about 150 mm from each end
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
Thickness	16 mm to 40 mm, size dependent

PTFE Lined Spectacle Blind — thickness and lining availability

Size	Face to face L (±2)	PTFE	PFA	FEP
1"	16	✓	✓	✓
1.5"	18	✓	✓	✓
2"	20	✓	✓	✓
3"	24	✓	✓	✓
4"	24	✓	✓	✓
6"	26	✓	✓	✓
8"	28	✓	✓	✓
10"	30	✓	✓	✓
12"	32	✓	✓	✓
14"	35	✓	✓	✓
16"	36	✓	✓	✓
18"	40	✓	✓	✓

All dimensions in mm. This item starts at NB 1" and runs to NB 18", unlike most of the range.

Available on request

ANSI B16.5 Class 300
Stainless steel body
Higher diameters on request

FAQ

Questions we are asked about this item.

Yes. The plate sits between two flanges and adds its full thickness — 16 mm to 40 mm depending on bore — to the installed length. Allow for it with a lined spacer or distance piece when setting out.

A valve can pass. A spectacle blind gives absolute isolation and, unlike a slip plate, shows its state from outside the line, which is what a permit-to-work usually requires.