Spectacle Blinds, Spades & Spacers
Giriraj Impex is a manufacturer, stockist, supplier and exporter of spectacle blinds, paddle blanks (spades) and paddle spacers to ASME B16.48, for use between ASME B16.5 and B16.47 flanges in Class 150 to 2500, with raised face and ring type joint facings. We manufacture spectacle blinds from plate and forgings in carbon steel, stainless steel, alloy steel, duplex and super duplex steel and nickel alloys, with mill test certificates.
Spectacle blinds, spades and spacers provide positive isolation of pipelines and equipment for maintenance, testing and start-up, in refineries, petrochemical plants, power stations and oil and gas facilities.
Types of line blanks
- Spectacle blind (figure-8 blank) – a solid disc and a ring joined by a web. It stays permanently between two flanges and is rotated to open or close the line, so the position is always visible.
- Paddle blank (spade) – a solid disc with a handle, inserted between flanges to close the line.
- Paddle spacer – a ring with a handle, inserted when the spade is removed to keep the flange gap and bolting the same.
Spectacle blinds are used up to sizes where their weight is manageable; above that, spades and spacers are used in pairs.
Positive isolation
A closed valve can leak, so where people must work on equipment, or where products must not mix, a line blank gives positive isolation – a solid metal barrier rated for the full line pressure. Spectacle blinds are installed at pump suctions and discharges, vessel inlets and outlets, battery limits of process units, and tie-ins to future lines. The blind must be designed for the flange class and the gaskets on both sides; ASME B16.48 sets the thickness for each size and class so that the blank can hold the rated pressure.
Because spectacle blinds stay in the line, they make the isolation status visible at a glance and are not lost between uses. For large sizes and high classes, lifting lugs or handles are added, and davits or jack screws on the flanges help spread them for turning the blind.
Specifications
| Item | Details |
|---|---|
| Dimensional standard | ASME B16.48 (line blanks); customer drawings for special sizes |
| Sizes | ½" to 24" NB, and larger to B16.48 or drawing |
| Classes | 150, 300, 600, 900, 1500, 2500 |
| Facings | Raised face (RF) to suit flat gaskets; ring type joint (RTJ) |
| Material form | Plate (e.g. ASTM A516, A240) or forgings (e.g. ASTM A105, A182) |
| Documents | Mill test certificate (MTC); third-party inspection on request |
Materials
- Stainless steel flanges – ASTM A182 F304/304L, F316/316L, F321, F347.
- Carbon steel flanges – ASTM A105, A350 LF2, A516 plate for spectacle blinds.
- Alloy steel flanges – ASTM A182 F5, F9, F11, F22, F91.
- Duplex steel flanges – ASTM A182 F51, F60.
- Super duplex flanges – ASTM A182 F53, F55.
- Inconel flanges – ASTM B564, and other nickel alloys.
All flange materials are on the flanges page.
How we manufacture spectacle blinds
Spectacle blinds for raised-face service are usually cut from plate of a grade compatible with the line flanges, then machined on both faces and the outside diameter, with the web and handle shaped to drawing. RTJ blinds and high-class blinds are machined from forgings, with ring grooves on both faces. Each blind is marked with material, size, class, facing and heat number, and the closed and open positions are clearly identified. Flange dimensions are in the flange dimensions chart.
Ordering spectacle blinds
Please give the type (spectacle blind, spade or spacer), material, size, class, facing, quantity and any drawing, coating or inspection requirement.
Frequently Asked Questions
A spectacle blind is a solid disc and a ring joined by a web, installed between two flanges and rotated to open or close a line.
ASME B16.48 covers line blanks – spectacle blinds, paddle blanks and paddle spacers – for use with ASME B16.5 and B16.47 flanges.
A spade is a solid paddle blank that closes the line; a spacer is a ring that keeps the flange gap when the spade is removed.
A valve can leak; a spectacle blind gives positive isolation with a solid barrier rated for the line pressure.
Raised-face blinds are commonly cut from plate; RTJ and high-class blinds are usually machined from forgings.
Yes. Spectacle blinds can be supplied with ring type joint grooves on both faces for RTJ flanges.
Request a Quote for Spectacle Blinds, Spades & Spacers
Tell us the product, grade, size, standard, quantity and delivery location, and our sales team will reply with a quotation.
Inconel® is a trademark of Special Metals Corporation.