Guardian Pressure Valve, NPS Swivel Connection

The Betts’ GuardianTM NPS swivel vent is a spring loaded reclosing pressure relief device/valve for use as a cargo tank’s primary pressure relief system. The pressure relief valve is designed, tested and marked in accordance with 49CFR §178.345-10, 49CFR §178.347-4 and 49CFR §178.348-4.

  • Compact Optimized Flow Design
  • 316 Stainless Steel construction
  • Teflon seals and wear components
  • Safety Stop Screw to help prevent accidental un-threading of housing
  • Seal tabs on shroud for security measures.
  • Simple In-Place Maintenance
  • Available ECTFE (Halar®) coated.
  • Multiple sizes and mounting options
  • Multiple seal options
  • 3″ and 4″ NPS Swivel Connection

Parts List

Product Details

Part NumberSize and ConnectionWeight lbs. [kg]
RVP3S*-**3" NPS SWIVEL15.8 [7.1]
RVP4S*-**4" NPS SWIVEL16.1 [7.3]
- An Example of a part number would be RVP3AT-25. This would have PTFE seals and be used on a 25 MAWP tank.
- Part numbers with ECTFE (Halar®) coating as follows: RVPL3A*-**. "L" indicates ECTFE coated.
- Values shown are test values. Actual results may vary due to service conditions.
* Seal Material CodeMaterialTemp. Range
TPTFE-40°F to +400°F [-40°C to +204°C]
FFluorosilicone-50°F to +350°F [-45°C to +176°C]
KKalrez-20°F to +400°F [-28°C to +204°C]
VBFKM BLT-15°F to +400°F [-26°C to +204°C]
Valve Size** Code
Tank MAWP
Set PressureRated Air Flow Capacity
(out-breathing)
Water Flow Rate
3"25 psig. [1.72 bar]30 psig [2.06 bar]379,462 SCFH @ 40 psig [10,745 SCMH @ 2.75 bar]980 gpm @ 40 psig.
3"25 psig. [1.72 bar]30 psig [2.06 bar]409,558 SCFH @ 45 psig [11,597 SCMH @ 3.10 bar]1050 gpm @ 45 psig.
3"30 psig. [2.06 bar]36 psig [2.48 bar]409,558 SCFH @ 45 psig [11,597 SCMH @ 3.10 bar]1050 gpm @ 45 psig.
3"35 psig. [2.41 bar]42 psig [2.89 bar]457,740 SCFH @ 52.5 psig [12,961 SCMH @ 3.62 bar]1075 gpm @ 52.5 psig.
3"40 psig. [2.75 bar]48 psig [3.31 bar]514,539 SCFH @ 60 psig [14,570 SCMH @ 4.13 bar]1100 gpm @ 60 psig.
4"25 psig. [1.72 bar]30 psig [2.06 bar]389,482 SCFH @ 40 psig [11,028 SCMH @ 2.75 bar]1000 gpm @ 40 psig.
4"25 psig. [1.72 bar]30 psig [2.06 bar]432,563 SCFH @ 45 psig [12,248 SCMH @ 3.10 bar]1100 gpm @ 45 psig.
4"30 psig. [2.06 bar]36 psig [2.48 bar]432,563 SCFH @ 45 psig [12,248 SCMH @ 3.10 bar]1100 gpm @ 45 psig.
4"35 psig. [2.41 bar]42 psig [2.89 bar]496,955 SCFH @ 52.5 psig [14,072 SCMH @ 3.62 bar]1150 gpm @ 52.5 psig.
4"40 psig. [2.75 bar]48 psig [3.31 bar]564,486 SCFH @ 60 psig [15,984 SCMH @ 4.13 bar]1200 gpm @ 60 psig.
Replace ** in Part Number to Designate Cargo Tank MAWP in PSIG
Notes: 1) Values shown are test values. Actual results may vary due to service conditions.
2) Set pressure is defined as point at which continuous flow is seen, felt or heard around the seat area. (nomenclature per ASME Section XII Part TR-110 and TTMA TB-126.)

Seal Kits & Accessories

Seal Kit part number: SK-RVPT*

*Mounting gasket not included in seal kit

Spanner wrench part number: 75825EY

Dis-assembly wrench number : 75819ZC