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Blind Flange/

ASTM A516 Gr. 65 Gr.70 ASME B16.48 Spectacle Blind Flange

1、What Is Spectacle Blind Or Figure 8 Blind? spectacle blind Flange ,also known as figure 8 Flange which is combination of the two that can be rotated to function as Single Bind or a Ring Spacer. This kind of flange is generally a piece of metal than is cut to fit between two pipe flanges and usually sandwiched between two gaskets a spectacle blind is often made from two metal discs that are attached to each other by a small section of steel. The Sharp is similar to a pair of glasses or spectacles - hence the name spectacle blind flange. One end of the blind will have an opening to allow flow through the pipe during operation and the other end…

  • Product Details

1、What Is Spectacle Blind Or Figure 8 Blind?

spectacle blind Flange ,also known as figure 8 Flange which is combination of the two that can be rotated to function as Single Bind or a Ring Spacer. This kind of flange is generally a piece of metal than is cut to fit between two pipe flanges and usually sandwiched between two gaskets a spectacle blind is often made from two metal discs that are attached to each other by a small section of steel. The Sharp is similar to a pair of glasses or spectacles – hence the name spectacle blind flange. One end of the blind will have an opening to allow flow through the pipe during operation and the other end is solid to block flow during maintenance. They are generally installed as a permanent device to separate process piping system.

The whole idea of a spectacle blind Flange is so that one can be absolutely sure that an item of equipment is properly and securely blanked off with no possibility of any flow or leakage through a valve during maintenance. The flow can be diverted to other items of equipment but not just by passed around the blank as this would compromise the safety function of the spectacle blind. The flow has to valve off and pressure relieved prior to loosening flange bolts and swinging the blind.

2、Spectacle Blind Flange Class & Types & Specification

Dimensions : ASME B16.48 

Material: ASTM A516N GR.70 

Size :1/2″ (15 NB) to 48″ (1200NB)

Class :150 LBS, 300 LBS, 600 LBS, 900 LBS, 1500 LBS, 2500 LBS, DIN Standard ND-6,10, 16, 25, 40 Etc.

DIN : DIN2527, DIN2566, DIN2573, DIN2576, DIN2641, DIN2642, DIN2655, DIN2656, DIN2627, DIN2628, DIN2629, DIN 2631, DIN2632, DIN2633, DIN2634, DIN2635, DIN2636,DIN2637, DIN2638, DIN2673

BS : BS4504 , BS4504, BS1560, BS10

Flange Face Type : Flate Face (FF), Raised Face (RF), Ring Type Joint (RTJ)

ASME SA 516 GR 70 SPADE PADDLE BLIND ASME B16.48

DIMENSIONS SPECTACLE BLINDS ASME B16.48

NPSOutside Ø
A
Inside Ø
B
Center Line
C
THK
t
Web Width
W
1/2451660338
3/4542170338
1642780338
1.1/47342906.438
1.1/283481006.438
2102611206.451
2.1/2107731406.451
3133891506.464
3.1/21591021759.764
41721141909.764
51941412159.776
621916824012.776
827621930012.776
1033727336015.7102
1240632443019.1102
1444835647519.1108
1651140646022.4108
1854645758025.4114
2060350863528.4121
2471461075031.8140

Dimensions of Spades and Ring Spacers ASME B16.48

Pressure Class 150
NPSOutside
Dia
A
Inside
Dia
B
Center
End
C
Thick
ness
t
Handle
Width
W
1/24516126332
3/45421131332
16427136332
1.1/473421456.432
1.1/283481456.432
2102611556.432
2.1/2107731706.432
3133891706.432
3.1/21591022029.738
41721142029.738
51941412259.738
621916822512.738
827621926712.738
1033727332215.744
1240632435719.144
1444835637819.144
1651140641022.444
1854645742725.451
2060350845528.451
2471461051231.851
Pressure Class 300
NPSOutside
Dia
A
Inside
Dia
B
Center
End
C
Thick
ness
t
Handle
Width
W
1/251161296.432
3/464211366.432
170271396.432
1.1/479421506.432
1.1/292481506.432
2108611589.732
2.1/2127731779.732
3146891779.732
3.1/216210220512.738
417811420512.738
521314124015.738
624816824015.738
830521928122.438
1035927333325.444
1241932436328.444
1448335639531.844
1653640642238.144
1859445745041.151
2065150848044.551
2477261054050.851
Pressure Class 600
NPSOutside
Dia
A
Inside
Dia
B
Center
End
C
Thick
ness
t
Handle
Width
W
1/251161296.432
3/464211366.432
170271396.432
1.1/479371509.732
1.1/292431509.732
2108551589.732
2.1/21276717712.732
31468317712.732
3.1/21599621115.738
419110821115.738
523813524819.138
626416224822.438
831821228828.438
1039726535235.144
1245431538141.144
1448934639844.544
1656239743550.844
1861044845953.851
2067949749363.551
2478759754773.251
Pressure Class 900
NPSOutside
Dia
A
Inside
Dia
B
Center
End
C
Thick
ness
t
Handle
Width
W
1/260161346.432
3/467211376.432
176271426.432
1.1/486371519.732
1.1/295431519.732
21405517412.732
2.1/21626718612.732
31658318615.732
420310821719.138
524413525922.438
628616225925.438
835621230735.138
1043226537041.144
1249531540147.844
1451834641253.844
1657239744060.544
1863544847166.551
2069649750173.251
2483559757188.951
Pressure Class 1500
NPSOutside
Dia
A
Inside
Dia
B
Center
End
C
Thick
ness
t
Handle
Width
W
1/261161356.432
3/467211379.732
176271429.732
1.1/486351519.732
1.1/2954115112.732
21405317412.732
2.1/21626319015.732
31727819019.132
420610221922.438
525112825628.438
627915425635.138
834920330341.138
1043225537050.844
1251830341260.544
1457533344266.544
1663838147276.244
1870242950485.951
2075247853095.351
24899575603111.351
Pressure Class 2500
NPSOutside
Dia
A
Inside
Dia
B
Center
End
C
Thick
ness
t
Handle
Width
W
1/267161379.732
3/473211409.732
183271459.732
1.1/41023516112.732
1.1/21144116115.732
21435317515.732
2.1/21656320119.132
31947820122.432
423210223228.438
527612827335.138
631415427341.138
838419832153.838
1047324839066.544
1254628942779.244
  • Dimensions are in millimeters unless otherwise indicated.
  • Spade Handles shall be solid with NO openings.

Further notes:

  • Ring Spacer Handles shall have a single through indicator hole located near the end of the handle. The hole diameter shall not be less than 12 mm.
  • Wt = Thickness of the handle should be 6 mm minimum, or equal to Thickness (t) if less than 6 mm.
  • Spades and Ring Spacers should be made from a plate or forging specification, approved for use by ASME B31.3, of essentially the same chemical composition as the mating flanges and piping involved.
  • Spades and Ring Spacers ASME B16.48 may be used for installation between ASME B16.5 flanges
  • Depending on a customer specification, some dimensions can be different from what on this page is defined.

3、Use Of Spectacle Blind, Spades And Spacers

Spectacle Blind, Spades and Spacers are used to provide flexibility during maintenance an operation. Therefore, it is essential to consider this during design of Piping system. Blanks are installed in horizontal line. In general, you can see the use of spectacle blind flange at following location;

  • At inlets and outlets of static equipment
  • At inlets and outlets of rotary equipment
  • At inlets and outlets of fired heater and common headers
  • In bypass line
  • At unit battery limit

4、Spec Blinds Are Available In The Following Face Type

  • Raised Face
  • Female Ring-Joint Blanks
  • Male Ring-Joint Blanks

5、Chemical Composition %

NiMoCrFeWCoMnC
Remainder15.0-17.014.5-16.54.0-7.03.0-4.52.5 max1.0 max.01 max
VPSSi    
.35 max.04 max.03 max.08 max    

6、Mechanical Properties

Product FormTensile (ksi).2% Yield (ksi)Elongation %
Bar110.052.662
Plate107.450.367
Sheet115.554.660
Tube & Pipe105.445.470

Our aim is to delight customers with top-notch service, competitive pricing, and high-quality ASTM A516 Gr. 65 Gr. 70 ASME B16.48 Spectacle Blind Flanges. Thanks to our professional teamwork, we’ve secured numerous long-term overseas clients. We eagerly await the opportunity to serve you as your trusted partner!

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