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Specials

Dimensions Square Edge Flow Metering Orifice Plates for ASME B16.36 Raised Face Orifice Flanges

Square Edge Flow Metering Orifice Plate
NPS DIA
D3
L N P T
1/2 13 0.24 1.5 30 1.5
3/4 19 0.34 1.5 30 1.5
1 25 0.42 1.5 30 1.5
1.1/2 40 0.64 1.5 30 1.5
2 51 1 2 30 2
3 76 1.5 3 40 3
4 102 1.5 3 40 3
6 152 1.5 4 40 4
8 202 3.5 6 40 4
10 253 3.5 6 45 4
12 302 3.5 8 45 5
14 341 6 10 45 6
16 392 6 10 50 6
18 443 8 12 50 8
20 494 8 12 50 8
24 595 10 16 60 12
NPS ASME B16.36 Flange Class
300 600 900 1500 2500
S
1/2 120 120 130 130  
3/4 125 125 135 135  
1 125 125 135 135  
1.1/2 120 120 145 145  
2 115 115 125 125 130
3 120 120 125 135 140
4 125 125 130 140 150
6 120 130 135 145 170
8 125 135 145 155 170
10 130 145 145 165 185
12 135 140 145 165 195
14 140 145 145 175  
16 145 150 155 180  
18 145 155 160 195  
20 150 155 165 205  
24 160 165 190 220  
NPS ASME B16.36 Flange Class
300 600 900 1500 2500
DIA
D4
1/2 72.4 72.4 78.6 78.6  
3/4 72.4 72.4 78.6 78.6  
1 72.4 72.4 78.6 78.6  
1.1/2 94.3 94.3 97.5 97.5  
2 110.6 110.6 143.8 143.8 146.4
3 148.1 148.1 169.7 175 197.6
4 180 194.6 206.9 209.5 235.7
6 251.8 267.1 289.6 283.9 317.1
8 308.3 320.6 359.7 353 386.9
10 361.8 400 435.5 435 476.2
12 422.2 456.8 498.3 520.4 549.2
14 485 492.3 520.9 577.6  
16 539.5 564.7 574.3 640.7  
18 596.3 612.2 637.4 703.8  
20 653.1 682 696.8 754.9  
24 774 789 837 901  

Tolerances

D1 & D2 = ± 1%
D3 = ± 1 mm
D4 = 0/-0.4 mm
L = ± 0.1 mm
N = see note 6
P = ± 0.1 mm
S = ± 0.1 mm
T = see note 2

Notes:

  1. Marking
    The Upstream side of the orifice tab shall be stamped at the indicated locations with:
    - the word UPSTREAM
    - the Tag Number
    - the ASME flange class, followed by RF
    - the nominal pipe size (NPS)
    - the measured orifice D1 (in mm)
    - the material of the orifice plate
    - the type of orifice plate (Square, Restriction etc.)
    Letter height approx. 4 mm
  2. Welding of tab
    Tab may be integral with orifice plate up to and including 7 mm plate thickness.
    In other cases full penetration joint to be applied.
  3. Finish of plate
    The upstream and downstream faces of the orifice plate to a diameter equal to D3 shall have a surface roughness Ra ≤ 0.8 µm ASME B46.1.
    The remaining annular part (between D4 & D3) of upstream and downstream faces shall have a surface roughness Ra between 3.2 and 3.6 µm ASME B46.1. This finish shall be obtained by machining with a round nosed cutting tool having a 0.8 mm radius at a feed rate between 0.35 and 0.45 mm per revolution.
  4. Concentricity
    The centre of the orifice shall not differ from the centre of the plate by more than 0.1 mm for ≤ NPS 8 and 0.2 mm for > NPS 8.
  5. Finish of throat
    The throat and outlet cone shall have a surface roughness Ra ≤ 0.4 µm ASME B46.1.
    All edges shall be sharp and free from burrs, so that when viewed with the naked eye no light is reflected by the corners.
  6. Plate thickness
    The difference between any two measurements of plate thickness, for annular part D1-D3, shall not differ by more than 0.001 DN in mm.
    The plate shall not depart from flatness along any diameter by more than 0.01 D3.
    Tolerance for N shall be:
    N ≤ 6 mm +0.1/-0.25 mm
    N > 6 mm +0/-1.5 mm
    Thickness for annular part D3-D4, may be slightly less, max 0.05 mm, due to surface finishing difference between D1-D3 & D3-D4. (see note 3)

General Notes:

  • Dimensions are in millimeters unless otherwise indicated.
  • DIA D1 & DIA D2 - to be specified by purchaser.
  • Material to be specified by purchaser.

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