851A High-Capacity Relief Valve, Aluminum, 3/4″ MNPT x 2″ MNPT

Item # 851A-3/4 Brand: Cyrus Shank

$708.45

Side Outlet: 2″ MNTP.

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This high-capacity relief valve was designed for use in large pressure vessels.

The ASME certified slope of 6.17 yields, for example, a capacity of 136.4 lbs. per minute of air @ 250psi set pressure.

All Cyrus Shank relief valves are manufactured in accordance with ASME Boiler and Pressure Vessel Code Section VIII Division I and stamped with The ASME Certification Mark with UV Designator.

All Cyrus Shank relief valve capacities are certified by The National Board of Boiler and Pressure Vessel Inspectors and stamped with The NB Certification Mark.

Features:

  • National Board Certification #: 51051
  • Set Pressure Range: 150-400 PSI in 25 PSIG increments
  • Light-weight anodized aluminum casting

850/851 Series Capacity Chart

Slope = 6.17 SCFM/PSIA
Standard Conditions [60 
˚F, 1 Atm]

Set Pressure (PSIG) Air SCFM Air lb/min Air lb/hr NH3 lb/min NH3 lb/hr R-22 lb/min R-22 lb/hr R-290 lb/min R-290 lb/hr R-404A lb/min R-404A lb/hr
150 1108.7 84.6 5078.2 64.9 3893.5 146.2 8773.7 104.4 6265.5 155.4 9321.1
175 1278.4 97.6 5855.4 74.8 4489.3 168.6 10116.3 120.4 7224.4 179.1 10747.5
200 1448.1 110.5 6632.5 84.8 5085.1 191.0 11459.0 136.4 8183.2 202.9 12174.0
225 1617.8 123.5 7409.7 94.7 5681.0 213.4 12801.7 152.4 9142.0 226.7 13600.4
250 1787.4 136.4 8186.8 104.6 6276.8 235.7 14144.3 168.3 10100.9 250.4 15026.9
275 1957.1 149.4 8963.9 114.5 6872.6 258.1 15487.0 184.3 11059.7 274.2 16453.3
300 2126.8 162.4 9741.1 124.5 7468.5 280.5 16829.6 200.3 12018.5 298.0 17879.7
325 2296.5 175.3 10518.2 134.4 8064.3 302.9 18172.3 216.3 12977.4 321.8 19306.2
350 2466.1 188.3 11295.3 144.3 8660.1 325.2 19515.0 232.3 13936.2 345.5 20732.6
375 2635.8 201.2 12072.5 154.3 9256.0 347.6 20857.6 248.3 14895.0 369.3 22159.0
400 2805.5 214.2 12849.6 164.2 9851.8 370.0 22200.3 264.2 15853.9 393.1 23585.5

Additional information

Brand Cyrus Shank
Weight 7.2 lbs
Set pressure

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NB Certificate

Max Working Pressure

Temperature range

Material

Size

Item Type

Side Outlet

Item #Description
851A-150-3/4Set pressure: 150
851A-175-3/4Set pressure: 175
851A-200-3/4Set pressure: 200
851A-225-3/4Set pressure: 225
851A-250-3/4Set pressure: 250
851A-275-3/4Set pressure: 275
851A-300-3/4Set pressure: 300
851A-325-3/4Set pressure: 325
851A-350-3/4Set pressure: 350
851A-375-3/4Set pressure: 375
851A-400-3/4Set pressure: 400